Building Openings Construction Manual: Windows, Vents, Exterior Doors 9783955532994, 9783955532987

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JAN CREMERS (ED.)

Building Openings Construction

Edition ∂

MANUAL WINDOWS VENTS EXTERIOR DOORS

JAN CREMERS (ED.)

Building Openings Construction

MANUAL WINDOWS VENTS EXTERIOR DOORS

Authors Prof. Dr.-Ing. Jan Cremers (Editor) Hochschule für Technik Stuttgart, University of Applied Sciences Research and illustration assistants: Melanie Monecke, Nansi Palla, Lukas Hüfner Prof. Dipl.-Ing. Markus Binder Hochschule für Technik Stuttgart, University of Applied Sciences CAPE climate architecture physics energy Dr.-Ing. Peter Bonfig Dipl.-Ing. Joost Hartwig ina Planungsgesellschaft mbH, Darmstadt

Hermann Klos Holzmanufaktur Rottweil Prof. Ulrich Sieberath, Dipl.-Ing. (FH) Wolfgang Jehl, Dipl.-Ing. (FH) Ingo Leuschner, ift Rosenheim, Institute for Windows and Facades, Doors and Gates, Glass and Building Material, Rosenheim Prof. Dr.-Ing. Elke Sohn Hochschule für Technik Stuttgart, University of Applied Sciences Prof. Dr.-Ing. Thomas Stark University of Applied Sciences Konstanz ee concept GmbH, Darmstadt

Editorial services Editing, copy-editing: Steffi Lenzen (Project Manager), Eva Schönbrunner Editorial assistants: Samay Claro, Marion Dondelinger, Carola Jacob-Ritz, Sophie Karst, Andrea Kohl-Kastner, Jana Rackwitz Drawings: Ralph Donhauser, Marion Griese, Simon Kramer, Gina Pawlowski, Kwami Tendar Translation into English: Christina McKenna and Michael Keith for keiki communication, Berlin Copy Editor (English edition): Matthew Griffion for keiki communication, Berlin Proofreading (English edition): Stefan Widdess, Berlin Production & layout: Simone Soesters Reproduction: ludwig:media, Zell am See Printing and binding: Grafisches Centrum Cuno GmbH & Co. KG, Calbe Publisher: Institut für internationale Architektur-Dokumentation GmbH & Co. KG, Munich www.detail-online.com © 2016 English translation of the 1st German edition

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ISBN: 978-3-95553-298-7 (Print) ISBN: 978-3-95553-299-4 (E-Book) ISBN: 978-3-95553-300-7 (Bundle) Bibliographic information published by the German National Library. The German National Library lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at http://dnb.d-nb.de. This work is subject to copyright. All rights reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, recitation, reuse of illustrations and tables, broadcasting, reproduction on microfilm or in other ways and storage in data processing systems. Reproduction of any part of this work in individual cases, too, is only permitted within the limits of the provisions of the valid edition of the copyright law. A charge will be levied. Infringements will be subject to the penalty clauses of the copyright law. This textbook uses terms applicable at the time of writing and is based on the current state of art, to the best of the author’s and editor’s knowledge and belief. All drawings in this book were made specifically by the publisher. No legal claims can be derived from the contents of this book. This book is also available in a German language edition (ISBN 978-3-95553-229-1)

Contents

Imprint

Part A

4

Introduction

1 Openings in buildings Jan Cremers 2 The historic development of the window – from its origins through to the early modern era Hermann Klos 3 Designing facade openings Jan Cremers 4 Windows and doors in art and culture Elke Sohn 5 Solution principles for adjustable openings Peter Bonfig

Part B 1

2 3 4

1 2 3 4

32 36

50 86 120

148

170 190 198 208

Built examples in detail

Project examples 1 to 30

Part E

24

Fundamentals II

Passive solar energy use Jan Cremers, Markus Binder Active solar energy use Thomas Stark Technical building components in and around windows Markus Binder Life-cycle assessments for windows and exterior doors Joost Hartwig

Part D

12

Fundamentals I

Requirements and protective functions – building physics fundamentals Jan Cremers with ift Rosenheim Materials, components, types of construction Jan Cremers Building connection and structural context Jan Cremers with ift Rosenheim Working with historic windows in existing buildings and architectural monuments Hermann Klos

Part C

8

220

Appendix

Authors Acknowledgments; Ordinances, guidelines and standards Literature Image credits Index

278 279 281 283 286

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Part A

1

Openings in buildings

2

The historic development of the window – from its origins through to the early modern era 12 Construction’s earliest origins 12 A brief, yet unsustainable flourishing 13 The Middle Ages and early modern era 13 Before glass there was wood 14 Paintings as sources 16 Materials 17 The “gold of the Middle Ages” 18 Glass production – the “arcane knowledge” of a powerful few 18 Breaking out of darkness 20 Local discoveries 20

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Designing facade openings 24 The relationship between a building’s openings and its envelope 24 The proportion of opening to space 25 Designing openings and the surrounding envelope 27 Opening as symbol, opening and ornament 29 Openings, transparency and reflection 30

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Windows and doors in art and culture Windows and doors – loci of special design and significance Doors as transitional space The window as picture frame – the effects of media The window as boundary A new culture of transition

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Fig. A

Introduction

Solution principles for adjustable openings The functions of adjustable openings Integrating openings in the building envelope Permeability and its modification Kinematics: principles and solutions Structures for planar structural elements in the building envelope

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32 32 32 33 34 35

36 36 39 41 42 44

Palazzo in Venice (I)

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Openings in buildings Jan Cremers

A 1.1

A building envelope is a boundary between inside and out; it has protective and regulatory functions and allows for the exchange of energy (solar radiation, heat), light and air. This occurs mainly through openings as they regulate other interface functions such as access. Building openings, windows and doors, let people inside see out and people outside see in, thereby becoming “backdrops” for human coexistence where inside and outside intersect. In this sense, they are of great social significance. They both separate and connect the private and the public. Building openings define the transition from introverted to exposed, from warm to cold, from artificial to natural, from dark to light, from enclosed to open space. Having a direct connection with the outdoors is important to a building’s users. Numerous studies have shown that users’ satisfaction with buildings is closely connected with the possibility of opening a window for fresh air [1]. Since most people now spend the best part of their day inside – in Central Europe about 80 – 90 % of it – building openings are becoming increasingly significant. People need to be able to establish a link with the outside, with our original living space, with nature, even though for a growing number of people the outdoors is now an urban space, a largely artificial environment. [2] Combining various functions can greatly increase the useful capacity of building openings and allow them to meet several requirements at the same time: controlling the penetration of light and exchange of air, functioning as emergency escape routes, providing access for emergency responders in emergencies and ensuring a controlled release of heat, smoke and gases in case of fire. Most openings offer more than just two states (“open” or “closed”) but allow for differentiated control of permeability. “Open” implies a complete opening (i.e. permeability), overcoming the physical boundary between inside and out. In contrast to fixed panes, through which light and energy can permeate, the function of ventilation is added here.

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It is precisely these multifunctional structural elements and components in and around building openings that are addressed in this book. It is not about openings that let light in but cannot be opened (i.e. all types of closed glass facades). Only elements in the building envelope that can be opened (“opened up”) are relevant for the purposes of this book. This also includes opaque elements that can be used to ventilate areas of the building. Traditional windows in all their local and historic variants, as well as opaque folding elements, doors and louvre windows, are all adjustable openings. All buildings, old and new, have such openings, so these structural components have a comparatively high market volume. In 2013, 13.1 million new window units for conventional windows (for new and existing buildings) were manufactured in Germany. The total number of windows in Germany is approximately 595 million units, representing a total window area of around 1 billion square metres. [3] Building openings are often supplemented by additional moveable components installed in front of, behind or within the opening (e.g. shutters, curtains, blinds, louvres, curtains etc.). These can be unchanging, such as wooden shutters, or changeable (e.g. adjustable sun protection blinds), and at several successive levels. A vast number of historic and contemporary forms and combinable complementary elements are now available. [4] Few other structural components reveal the enormous transformation process in building technology as clearly as building openings do. An old, single-paned, wood-framed window of the type made for centuries in a range of different local forms has little in common with today’s industrially manufactured products in terms of the resulting product, manufacturing process, function and range of features. These developments are a consequence of growing worldwide standardisation and unification, which are often perceived locally as a disadvantage and loss of quality. Seen from a design point of view, today’s

Openings in buildings

A 1.1

Folding windows at the Embassy Court apartment house, Brighton (GB) 1935, Welles Coates A 1.2 Stone sliding shutter as a closable opening, house in Stein, Kraichgau (D) 1524 A 1.3 Window with vertically and horizontally folding shutters, house in Geimen near Blatten, Valais (CH) A 1.4 Curving glass wall with no visible frame and a marble-clad sliding door into the garden, Villa in Ede (NL) 2007, Powerhouse Company A 1.2

standard windows rarely have aesthetic and functional qualities like those of historic windows. While openings were traditionally kept fairly small mainly for structural and energy conservation reasons, very large openings are now possible, e.g. multistorey windows or facade-high doors. No other part of a building reveals the constantly growing demands on the building envelope and resulting conflicts like its openings do, because the different requirements do sometimes conflict with each other. How can a building be made more airtight while also ensuring a minimum hygienic exchange of air? How can effective

sun protection, as well as a sufficient supply of daylight and passive solar energy use, be provided for? Some reasons for this rising complexity lie at the global level, in the growing scarcity of energy and material resources and constantly increasing volumes of waste, while others are of local origin, such as the cumulative regulation of building products and processes due to the Europeanisation of standards and approvals processes. At the same time, the disciplines involved in planning and construction are becoming more specialised, contractual regulation is becoming more important and various building certification

A 1.3

systems may have to be taken into account, so the planning and construction process is not getting any easier. This book regards openings as an essential architectural design element in the overall design and construction process and gives planners the specialist information they need to manage today’s complex requirements in planning for new and existing buildings. Changing usage, which can be expected in any new building, means that building openings often have to be redesigned, reduced, extended, closed up or created completely anew.

A 1.4

9

Openings in buildings

A 1.5

A 1.6

Ideally, openings should enhance the capacity and potential of the building envelope while reducing its material and technological complexity and expense. Planned correctly, they can offer substantial potential for reducing the need for air conditioning (ventilation, cooling and heating) and the amount of artificial light required as well as improve fire protection and access areas (e.g. by eliminating the need for emergency staircases). The control options and adjustability of openings vary widely, ranging from conventional (manual) opening mechanisms to centrally controlled, fully automated motorised systems. This linking of building openings and automation controls, with expanded options for user interaction, operation via mobile apps, for example, and the increasingly integrated functionality of building openings through to the development of windows as “mechatronic” structural elements will be the major future trends. From the architect’s point of view, methodically designed systems with a range of different materials and features would be desirable. Before going into concrete current technical and construction issues, the first part of this book addresses overarching aspects of the topic, beginning with historic descriptions of the earliest building openings and concluding with the early modern era (see “The historic development of the window – from its origins through to the early modern era” (p. 12ff.) continuing with “Designing facade openings” (p. 24ff.), and the significance of “Windows and doors in art and culture” (p. 32ff.). This section concludes with a discussion of various “Solution principles for adjustable openings” largely independent of specific material and construction considerations (p. 36ff). Subsequent chapters focus on concrete planning and implementation in practice. The fundamentals of planning and planning contexts are first described in Part B, while Part C (p. 168ff.) goes into further detail and covers cross-cutting issues such as active and passive solar energy use and life-cycle considerations. Since an architect’s freedom to work is ultimately based on knowledge and skill, descrip-

tions of potential solutions are largely dispensed with in the formulation of basic protective functions and structural-physical aspects. Rather, this section should be considered more as a detailed and annotated checklist for the various essential requirements. The following sections cover potential materials, components and types of construction for the building opening itself (p. 86ff.), while the question of how a building opening can be set into a building is dealt with in the chapter on “Building connection and structural context” (p. 120ff.). The final chapter of “Working with historic windows in existing buildings and architectural monuments” (p. 148ff.) not only builds on the preceding chapters – in which there was no differentiation between work on new and existing buildings – but also uses a chronological perspective to create a natural transition to the historical considerations (see “The historic development of the window – from its origins through to the early modern era”, p. 12ff.).

A 1.7

A subsequent chapter dealing with the very topical issue of “Passive solar energy use” (p. 170ff.) is dealt with in the context of the building’s energy balance and natural lighting (thermal insulation in summer and winter), while the following chapter describes the diverse possibilities for active solar energy use in the area of building openings (p. 190ff.). Complementing this chapter, the section on “Technical building components in and around windows” (p. 198ff.) provides an overview of the numerous technical options now available for windows such as distributed ventilation units and heat recovery. The concluding chapter (p. 208ff.) deals with issues essential to a comprehensive consideration of “building openings” by focusing on the life cycles of windows and exterior doors. As in previous DETAIL construction handbooks, a selection of “Built examples in detail” follows (p. 218ff.). These are chosen based on the criterion of successful implementation

A 1.8

10

Openings in buildings

of “building openings” in practice. Aiming to present the largest possible spectrum of various materials (for building openings and opening elements), types of movement, building usages and international locations, this section features many new buildings as well as examples of successful work on existing structures (renovating openings by replacing them as well as by retrofitting and reinforcing old structures). New windows are not invariably better than old ones, not just for ecological (saving energy and resources) and conservation reasons, but also for design reasons. A wide range of effective means is now available for retrofitting existing windows in almost all areas (see “Working with historic windows in existing buildings and architectural monuments”, p. 148ff.). It would be presumptuous to claim that the projects chosen give readers a complete picture of the topic. Instead, the examples presented are designed to outline the wide range of building opening design options available and, despite the comprehensive requirements now made on them, to inspire planners to develop individual solutions.

A 1.9

A 1.10

The process of design and construction is never completely straightforward but iterative, so constraining conditions such as design, function, technical requirements, feasibility and economy must be repeatedly reviewed. For good architecture, this means that objectively and subjectively unquantifiable criteria must be constantly considered and balanced. This book, with its wealth of specialist information aims to help planners do just that.

Umwelt-Survey (KUS) – Aufenthaltszeiten und -orte der Kinder in Deutschland. 1. Jahrestagung der Gesellschaft für Hygiene, Umweltmedizin und Präventivmedizin. 22 – 24 November 2007, Bielefeld. Abstract für die Jahrestagung der GHUP. In: Umweltmed Forsch Prax 12 (5) 2007, p. 266 [3] see Verband Fenster+Fassade and Bundesverband Flachglas e. V.: “Mehr Energie sparen mit neuen Fenstern”. Updated on 03/2014 via “Im neuen Licht: Energetische Modernisierung von alten Fenstern” study, Frankfurt am Main / Troisdorf, 03/2014. This study on the German windows market continues a series of investigations that the VFF has published regularly since 2002. It contains the VFF’s updated statistical basic data and resulting calculations on the potential energy savings resulting from the use of new windows in German housing (new and existing buildings). The German market volume for the years 1971– 2013 was 11.6 (minimum in 2005) to 25.5 (maximum in 1995) million new window units produced every year. For the purposes of these statistics, one window unit equals a window with an average area of 1.30 ≈ 1.30 m (1.69 m2). The rate at which windows are replaced annually is currently approximately 2.2 %. [4] A summary on this topic can be found in Herzog, Thomas; Krippner, Roland; Lang, Werner: Facade Construction Manual, Basel 2004, p. 259 – 263.

Notes: [1] A comparative compilation of relevant studies can be found in “Thermische Behaglichkeit. Unterschiede zwischen frei und mechanisch belüfteten Bürogebäuden aus Nutzersicht”. Hellwig, Runa Tabea, dissertation, TU Munich 2005 [2] Various studies have shown that in Germany, adults aged from 25 to 69 spend an average of about 20 hours inside daily, 14 hours of it in their own homes, so Germans move about outside for only 4 hours a day on average. Central Europeans spend about 80 – 90 % of their day inside, at home, at work and in transport. Source: Jahresbericht UBA 07/2003 and Schulz C., Seiwert M., Becker K. inter alia: Kinder-

The book offers a broad overview of technical, technological and structural contexts but also seeks to encourage readers to rethink the usual and the familiar.

A 1.5

Detail of the northern facade with distributed ventilation appliances, housing development, Hamburg (D) 2013, architekturagentur A 1.6 Inner courtyard facade with wooden shutters, “The Waterhouse” hotel, Shanghai (CHN) 2010, Neri & Hu Design and Research Office A 1.7 Sunshades and screens, Forschungsanstalt Geisenheim, FH Wiesbaden (D) 2009, Staab Architekten A 1.8 Openings in bay windows, nursing home extension, Bruneck / South Tyrol (I) 2010, Pedevilla Architekten A 1.9 Veranda with a bamboo facade, translucent polycarbonate roof and textile panels handwoven from palm leaves as sunscreens, vocational school, Rudrapur (BD) 2005, Anna Heringer A 1.10 Loggia, holiday house, Vitznau (CH) 2011, Lischer Partner Architekten Planer A 1.11 Sliding paper-covered panels used as room partitions (Shōji), Katsura Imperial Villa, Kyoto (J) A 1.11

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The historic development of the window – from its origins through to the early modern era Hermann Klos

A 2.1

“After forty days Noah opened a window in the ark he had made and sent out a raven.” This passage from the Bible (first Book of Moses (8, 6 –7)) has led literature professor Rolf Selbmann to claim that “It was God who ordered the first window” [1]. Contemporary representations show the window in Noah’s ark as a wooden shutter fixed to the roof by hinges (Fig. A 2.2). The Holy Spirit instructed Noah, “A window shalt thou make to the ark and in a cubit shalt thou finish it above” [2]. Nowadays there are no houses without windows. Only structures such as cellars, shelters or commercial spaces lack them. Author Erich Kästner imagined houses without windows when writing about a town hall with no windows in his “Land der Schildbürger”, the German equivalent of the home of the English “Wise Men of Gotham”. The people bring light into the building in buckets or bags or uncover the roof [3]. Such stories and tales, as well as many scientifically researched findings, have clearly contributed to the cultural and developmental history of the window.

A 2.1

A 2.2 A 2.3

A 2.4

Stratigraphic findings from prehistoric times, including the Stone, Bronze and Iron Ages, show that in Europe people lived from hunting and gathering and sought protection and shelter in caves, holes in the ground, pits, under overhanging rock ledges or in tents [4]. Archaeologists have also researched similar habitations in Africa and dated them from the period of Homo erectus, more than 1.5 million years ago. Walls of heaped stones 3 metres thick formed the basis of these simple huts made of sticks. Round huts made of large heaps of bones and stones with fireplaces in front of them, unearthed during excavations in the Thuringian Basin near Bilzingsleben, are the oldest such dwellings (around 300,000 years old) found in Central Europe [5]. Farming and animal husbandry evolved only at the end of the last glacial period, some 12,000 years ago, when people began to build solid housing. For centuries, huts and houses did not have windows. The window in its familiar modern form appeared in housing construction in Central Europe about 800 years ago and is a recent building element in terms of construction history. Archaeologists discovered Great Britain’s oldest house in 2008. The well-documented roundhouse is estimated to have been built around 11,000 years ago when Great Britain was still part of the European continent and connected to Europe by a land bridge. Researchers had previously assumed that the first settlers arriving in Great Britain after the end of the last ice age had been nomads and that they had left little evidence of their wanderings. The round hut discovered in northern England was built of timber piles and probably had a thatched roof. Experts assume that other huts once stood around it. Finds such as parts of a rudder, arrowheads and deer skulls indicate the settlers’ way of life. They seem to have kept domestic animals, hunted wild animals and fished in a nearby lake (Fig. A 2.1) [6]. Researchers assume that in the 6th century B.C. there was no need for fixed housing on

Stone Age settlement, around 9,000 B.C., illustration from Manchester University (after a painting by Alan Sorrell) Noah’s Ark, modern representation from around 1970 Reconstruction of a Carolingian village at Münsterbauhof in Zurich (CH) from the second half of the 9th century Casement window from the Terme Suburbane in Herculaneum (I), 1st century A.D. A 2.2

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Construction’s earliest origins

The historic development of the window – from its origins through to the early modern era

what is now the European continent. Nomadic hunter-gatherers did not need permanent abodes. The first people to settle in this region were, so to speak, migrants. DNA analyses have shown that they came from south-east Europe. Settled life was hard. Settlers had to work twice as hard as the hunter-gatherers to survive, but they had a roof of their own making over their heads that provided shelter and protection from wild animals, hostile neighbours and unpleasant weather. Rudimentary as they were, the building of fixed fireplaces and sleeping places created qualities of life that still form part of today’s basic human requirements. Over the centuries, the construction, materials and building techniques used in these dwellings changed very little. The oldest farming settlements on the European continent date from the 6th century B.C. The houses and huts of the first prehistoric housing dating from 6,000 B.C., the Bronze Age lakeside settlements and the so-called pile dwellings and Germanic-Alemannic houses built in the first millennium of the Christian era were invariably wooden structures built at ground level, or pile dwellings or pit houses dug into the earth. Their steeply pitched ridged roofs, some of them reaching to the ground, rested on massive ridge poles, and their initially split, later axe-cut poles were anchored in the ground. They were built using materials that were locally available. Their walls were made of wattle and daub, and they were roofed with straw or reed thatch or shingles. Even without windows, such houses were not impervious to light and air. Their cracks and joints let plenty of daylight in. There were no window openings because the houses were little used during the day. One common aspect of these types of dwellings is that, as well as a door, they had a hole that let light in and smoke out, which was to remain a feature of houses until the development of the masonry chimney in the late Middle Ages [7]. Any other opening was neither necessary nor desirable (Fig. A 2.3).

A brief, yet unsustainable flourishing An exception to Central Europe’s windowless early history was the period of Roman occupation. The Imperium Romanum brought with it many technical innovations in construction, such as masonry, tiled roofs, hypocaust heating and even glazed windows, in the areas it occupied. Cast panes with an edge length of up to 70 cm have been found in excavations in Pompeii. These were poured into a casting frame strewn with sand, which produced a window glass that was only even on one side and thus of limited transparency. The Romans also developed clear, blown window glass. Glazed windows were installed especially in public baths to ensure a consistent indoor

climate and sufficient light. A large piece of window glass is on display in the Roman baths at Zülpich, and countless fragments were found during the excavation of the Zülpich baths in 1978 /1979, with seven shards retrieved from undisturbed layers. They are cloudy, greenish, bluish or clear, with a slightly rough underside and smooth upper side. The rough underside and their varying thickness are a result of the technique used to produce them. Glass for windowpanes was poured into flat forms and drawn with tongs to the edges. The relatively small Roman panes of glass, which were fixed in bronze, lead, wooden or stone frames, were usually assembled to glaze large windows [8]. To reduce and prevent the formation of condensate, the Romans developed double-glazed windows and casement windows at a very early stage, especially for public baths (Fig. A 2.4). Such a casement window was found in the late 1980s in the Suburban Baths in Herculaneum. The window had been destroyed and buried by the eruption of Vesuvius in 79 A.D. Archaeological research has shown that the Romans used various techniques for setting and framing window glass as well as for manufacturing fixed panes and moveable window sashes. Researchers assume that the first glass was brought from Egypt to Rome and from there to the Germanic provinces [9]. The accelerated technical development of hypocaust heating and glass windows coincided with the Roman Empire’s expansion into Gaul and Germania. One of the motives for this acceleration may have been to make the unusually cold and damp climate there more pleasant for civilians and soldiers. Their barracks had, if not hypocaust heating, at least a stove and a glass window in every room. Even the watchtowers along the Limes, the Roman frontier, were equipped with glazed windows.

A 2.3

Sources show that every legion had its master window glazier. Archaeologists have identified more than 1,000 Roman glass windows across the territory of the modern state of BadenWürttemberg and have found a similar concentration in other regions such as Rhine-Hesse [10]. As the Alemanni advanced and the Roman Empire declined in the mid-3rd century, Roman construction techniques and their high building standards fell into oblivion. The Dark Ages had begun, and it would be a 1,000 years before the Renaissance once again brought about comparable building standards.

The Middle Ages and early modern era Sources on construction in the Middle Ages and the early modern era are fairly few. The oldest written documentation, the legal records of the Alemannic tribes, the “Pactus legis Alamannorum” for the 7th century, and the 8th-century “Lex Alamannorum” contain precise descriptions of the period’s settlement strucA 2.4

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The historic development of the window – from its origins through to the early modern era

0

2

4

0

50

A 2.5

tures, construction and housing culture. The construction of houses and the materials used is described in great detail. There are mentions of doors but not of other openings such as windows [11]. The oldest evidence of diamondpane glazing has been found at Wiremouth Abbey near Durham in Ulster in Northern Ireland, which was probably made in the 9th century A.D. [12]. Diamond-shaped panes have also been found in a pit hut near St. Ulrich and Afra in Augsburg and dated to the 8th or 9th century [13]. The oldest 4th-century castle ruins and the oldest still inhabited castle at Meersburg have not yielded any findings on the closing of window openings in this period, and very few such openings have been found. Archaeological literature relies mainly on reconstruction drawings. Remains of windows and doors have been discovered in various archaeological excavations in the primary debris of destroyed or abandoned castle complexes. Traces of windows, in the form of lead rods and shards of glass, were found during excavations of the lowland castle of Husterknupp near Grevenbroich in the northern Rhineland, which was destroyed around 1200. In the 9th century, a new castle was built on the ruins of a Frankish aristocratic estate in Bad Urach on the Runde Berg mountain, which was settled in prehistoric times. The comfortable new castle was equipped with tiled ovens and glass windows. The shards of glass found there make up a

A 2.6

diamond-shaped windowpane with an edge length of 8 to 10 cm (Fig. A 2.5). These are small pieces of mainly bluish-light green glass, which were worked along the edges with a rebate iron, a small hook-shaped instrument used to break pieces off glass panels or glass containers. Further finds testify to 12th century castles and fortresses whose inhabitants could afford glazed windows, at least in some areas. How rare these findings are, for example, is shown in surveys by Lorenz Frank, who evaluated the window openings in around fifty 12th and 13thcentury manor houses, castles and palaces, without investigating the ways in which the windows closed [14]. Researchers assume that even in palaces, wooden shutters were mainly used to close windows. Iron window shutter fittings have been found in other excavations. The physical sources of such glass and metal objects can be identified, but these materials cannot currently be dated. What is certain is that from the 13th century on, the upper stories of castles and palaces had large windows, some of them glazed, often facing south and equipped with a bench to sit on. This is recorded in archives and by findings of panes of bullseye glass [15]. Windows and other furnishings, such as stoves, furniture or tapestries, are explicitly listed in inventories of estates. At the basement level, there were slit openings secured with gratings. Pictures

dating from before 1300 show that mainly prestigious buildings had large openings, but there are no further details on how they closed. Historians assume that glass, a dense, transparent but expensive material, was reserved for the nobility.

Before glass there was wood Very comprehensive investigations into the oldest in-situ and completely preserved wooden house in Europe, which was built in 1176 in Nideröst in the Swiss canton of Schwyz, has yielded no findings on windows (Fig. A 2.7). Just two hatches on the building’s western wall dating from the time when it was built have been identified, one of which could be closed with a shutter, the other with a wooden board. No other window openings from the time of the building’s construction were identified, because they were probably in the area of the more recent, enlarged window. Only one piece of a windowpane was found in archaeological layers [16]. These findings have been confirmed and supplemented by other investigations carried out by Ulrike Gollnick into late 13th and early 14th-century houses in the canton of Schwyz [17]. She has also documented five original hatch-type window openings about 80 cm wide and 20 cm high at Haus Herrengasse 15 in Steinen. They formed a row of windows and were closed with a

A 2.5

Reconstruction of a 9th /10th century windowpane from the Runde Berg near Bad Urach (D) A 2.6 Views and sections of a window from around 1500, St. Peter’s Church, Fritzlar (D) A 2.7 Haus Nideröst, Schwyz (CH) A 2.8 Sketch of a hatch window with sliding shutter A 2.9 Hatch window, Gütschweg 11, Schwyz (CH) A 2.10 Openings for lighting, Bohlenstube 2nd floor, Hafenmarkt 8, Esslingen (D) late 13th century A 2.11 Hatch openings from 1331, wooden board with sliding dovetails and trunnions, a convenient solution for this period, as they are made without expensive iron fittings, Hafenmarkt 8 and 10, Esslingen (D) A 2.12 Openings for lighting in a Gothic house, Bohlenstube 2nd floor, original window from the time of the house’s construction with window rebate (bricked up), Leutkirch (D) 1377 A 2.7

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The historic development of the window – from its origins through to the early modern era

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Vertical cross section

A 2.8

A 2.9

A 2.10

sliding wooden shutter (Fig. A 2.8). Figure A 2.9 shows such a hatch-type opening typical of Swiss houses in the 12th and 13th centuries. Researchers also discovered an opening in the exterior kitchen wall for the release of smoke, the only exemplar of its kind known to exist [18]. Few objects have been found and few sources are available on houses and huts in the High Middle Ages due to a lack of images and texts. Existing images and archive records deal mainly with sacred and biblical topics. Sources and findings show that superb decorative windows were incorporated into church construction as early as the 11th century, for example, in St. Denis Cathedral. In contrast, there is little detailed information available on windows in secular buildings. Only the beginning of the Renaissance brought more daylight into the houses of peasant populations. Researchers believe that in the early 13th century in Basel and Strasbourg even the better types of houses, i.e. stone houses, had only a few small windows that let in very little light. Such windows were simply openings for light and air, purely expedient apertures in the masonry. Only from the 13th century did they become an essential architectural element in the house’s overall design. In late 12th-century Zurich, just a few window openings in townhouses are documented. The oldest opening is a compact round-arched window dated to 1170 in the western wall of the core building of

the historic listed “Zum Roten Mann” house in the district of In Gassen 1 in Zurich. Swiss archaeologists assume that the few modest window openings in early stone buildings were closed by means of interior shutters, because archaeological investigations show that holes for the dowels for hinge pivots of folding and pivoting shutters were attached subsequently to the Romanesque and early Gothic windows. Only after the 14th century did the buildings’ original openings have a rebate stop for attaching wooden shutters or transparent windows [19]. To provide protection from weather and let in light, animal skins and bladders, sheets of parchment, thinned horn, glazed linen, alabaster or similarly translucent materials were stretched on moveable wooden frames and set into window openings. In 1378, even the windows of prominent buildings, such as the Bern city hall, were closed in this way. Finds in the Zurich area indicate that windows in some secular buildings had flat glass panes from the 13th century [20]. Finds in southern Germany have shown that window openings in manorial townhouses back then were usually about A4 to A3 in size in today’s measurements, although this only applies to sitting rooms (Fig. A 2.10). As with the details of windows in Zurich described above, interior rebates suggest that windows in southern Germany may also have been closed with a wooden flap or glazing (Fig. A 2.12).

Further developments in building technology resulted from a wave of cities being founded across the Holy Roman Empire after the 11th century [21], which involved comprehensive construction measures. The new cities had planned streets, water supplies and drains. Multistorey stone houses with cellars, prestigious upper-storey rooms and large windows have been preserved from this period. Only after the 15th century did they usually have glazed windows. Even in the city hall in Zurich, the last linen windows were replaced by glass windows only around 1500. Interior, wooden shutters attached at the sides of the window reveals, some of them divided into several partitions with only small openings to let in light in their boards, were used to close windows. Alternatively, there were also exterior shutters and variations on them, such as vertically sliding or folding shutters or horizontally sliding shutters. Despite the many assumptions and interpretations made, current research has yielded no solid evidence on the frequency of glazed windows in secular buildings in the Late Middle Ages. The few archeologically classified finds confirm that glass, the “Gold of the Middle Ages”, tended not to end up in building rubble, but was often reused.

A 2.11

Glass windowpanes developed out of wooden shutters or boards covering window openings.

A 2.12

15

The historic development of the window – from its origins through to the early modern era

Wooden shutters or hatches with frames and panels could easily be made using the techniques used to make furniture (Fig. A 2.11, p. 15). Whether and to what extent other transparent materials were used is not clear due to the lack of adequate sources and findings. A wooden shutter, which closed openings at night when it was cold or in the absence of the inhabitants, provided solid closure. The moveable shutter with wooden pins or iron fittings was an improvement on this, an innovation that was followed by small openings in the shutter’s boards, which could be closed with glass or another transparent material (Fig. A 2.6, p. 14). Combining wood and glass was an expensive convenience and did not offer much protection from intruders. Satisfactory closure was ensured only by a combination of glazed windows and shutters. This arrangement, which became standard around 1500, has changed little to this day, although further developed and refined as described below and in the chapter on “Working with historic windows in existing buildings and architectural monuments” (p. 148ff.) in detail.

out of the art of the southern Netherlands, naturalistic realism now predominated. Painters depicted landscape and architectural details, spatial perspectives, lighting effects, colours and interiors, often in photographic precision down to the last detail. The window has always been a popular subject in painting. Windows and paintings have many parallels: both show a framed field of vision. Since the discovery of central perspective in the Renaissance, the picture as a window to another world has been a popular metaphor. The possibility of using the image of a window to represent the transition from the interior to the outside world has fascinated painters. A picture is like a window and every window frames a picture. A window marks the boundary between private living space and public space, a spectacle and genre in painting over centuries. Few motifs offer artists so much space to experiment as the window. Finally, a window is also a picture within a picture, directs the gaze and inspires us to think about the nature of painting (see also “Windows and doors in art and culture”, p. 32ff.) [22].

Paintings as sources

Before the late 14th century, window openings in secular buildings were usually represented without glazed windows. As a painting of the city of Constance from this period shows, windows in houses were usually open or closed with translucent materials, while the windows of the church in the painting are glazed with diamond-shaped panes. In a depiction of a weaver at his loom from the house book of the Mendelsche Zwölfbrüderstiftung charitable foundation from around 1425, only one of the windows has the diamond-pane glazing typical of the period. All the other openings were closed with wooden shutters at night and

Late medieval to early modern panel paintings are a treasure trove for window researchers. 14th century painters dealt almost exclusively with religious subjects. They depended on ecclesiastical and aristocratic patrons, so they focused on Christian subjects and Biblical figures. Portrayal was an honour reserved mainly for rulers. The common man and his needs were not depicted. Only a few exceptions, mainly of Italian provenance, show purely secular subjects. From the early 15th century, however, a new style became established. Arising

in cold weather. One glazed window provided enough permanent lighting. Early works such as the depiction of Siena by Ambrogio Lorenzetti, painted between 1337 and 1339, show complex urban development with high technical standards. Lorenzetti’s fresco shows the prosperity and propriety of the citizenry as the fruits of good government. It depicts an established, regularly laid-out cityscape: the city as an economic, cultural and mercantile centre. The houses are wellmaintained, with tiled roofs and adequate openings for light and air (Fig. A 2.13). Many houses have chimneys and flues, but there are no glazed windows. Interior wooden shutters with panels closing some openings are identifiable however. Stephan Lochner’s miniature of “St Jerome in his study” from around 1435 shows articulated windows with fixed diamond-shaped panes of glass in the protected upper areas (Fig. A 2.14). The leadlighting is secured with tap wrenches to keep it stable, as leadlight windows still usually are today. Tap wrenches prevent these windows from bulging due to wind pressure and the sagging of the leadlighting. Lower openings could also be closed with glazed canvas or animal skin. Wooden shutters opening inward were standard in this period. The central panel of Robert Campin’s Mérode Altarpiece (1425 –1430) shows an Annunciation scene with a high degree of realism (Figs. A 2.15 and A 2.16). Campin’s representation is no longer limited to the essential traditional attributes; instead he has transferred the biblical scene into a richly furnished interior. The central and right-hand panels depict realistic details of possible windows typical of early 15th-century homes of the nobility. The four-sashed, crossbar windows have

A 2.13

A 2.14 A 2.15

A 2.16 A 2.17

A 2.13

16

A 2.14

Ambrogio Lorenzetti, detail from the fresco “The Effects of Good Government in the City”, Siena (I), Palazzo Pubblico Stephan Lochner, “St Jerome in his Study”, 1435, Raleigh (USA), North Carolina Museum of Art Robert Campin, Mérode Altarpiece, middle panel, 1425 –1430, New York (USA), Metropolitan Museum of Art Robert Campin, Mérode Altarpiece, right-hand panel, detail Derick Baegert, “St Luke Painting the Virgin”, from around 1485, Münster (D), LWL-Museum für Kunst und Kultur

The historic development of the window – from its origins through to the early modern era

fixed, diamond-shaped panes and a coat of arms inset in the upper, protected part. Large lower openings can be secured by day with a wooden lattice to keep intruders and animals out. At night, during cold weather and in the absence of the inhabitants, the windows were closed with segmented folding wooden shutters. Valuable glazing, at this time almost exclusively made in the form of small diamond-shaped panes, was only used for the protected upper areas of the crossbar windows. The Annunciation scene shows multifunctional folding wooden shutters in the lower areas of the window that can be folded along various heights and widths and adapted to various situations. The triptych’s right-hand panel depicts Joseph making mousetraps (Fig. A 2.16). Here too, the painter shows a great love of realistic detail shared by few others of his period. Joseph’s workshop does not need glazed windows: Cleverly hung wooden shutters are used to close the window. A pivoting shutter is attached to the right-hand opening. The middle openings can be closed at the top with folding shutters hung from above, while the lower parts are closed with sliding shutters extending under the windowsill, one of which is pulled up. The painter has depicted almost all the types of closings for window openings customary in this period. The Rolin Madonna, painted around 1435 by Jan van Eyck, and “St. Luke painting the Virgin” (1485) by Derick Baegert (Fig. A 2.17), which both depict segmented glazing in adjoining rooms, show that glazing not only served as protection against the weather, but was also used to highlight colour and darken the room. This era produced many similar paintings showing interiors that represent the highest technical building standards of the period. A “Virgin and Child” from the Book of Hours of Folpard van Amerongen, which was made around 1450 –1460, shows an interior with an extensive and lavish arrangement of windows (Fig. A 2.19, p. 18). Here too, the top sections of the window glazing features diamondshaped panes stabilised with tap wrenches to resist wind pressure and deformation. The lower areas have a moveable wooden lattice for ventilating the room. These windows can also be closed with folding wooden shutters segmented vertically and horizontally: slatted, framed and filled shutters. It is only a small technical step from here to glazed windows. If you exchange the wooden lattice for glazing, you have a simple form of pivoting sash window. The same can be imagined with the panelled wooden shutters. Replacing the cassette panels with glazing would produce what was for this period a quite adequate window closure. Just a few decades later, this solution can be seen in the 1485 painting by Derick Baegert mentioned above (Fig. A 2.17). What is interesting here is that the room features high-quality,

elaborately made and designed window closures as well as large openings in the wall right next to them that lead directly outside and are roofed over only with a porch. Lucas Cranach the Elder offers us a precise depiction of the period’s windows in his 1532 painting of “The ill-matched couple” (Fig. A 2.20, p. 18). At this time, the dominance of medieval piety in painting was declining and secular subjects were increasingly portrayed, as here in the genre painting of the disparate couple, a popular subject in the 16th century. The window shown in the background is depicted in great detail, with bullseye panes of “forest glass”, set in rebates and secured with a strip to tap wrenches, decorative forged metal fittings and open sash locks that hold the flush-closing sashes. This small selection of paintings charts the development of the window from the 14th to the early 16th centuries to the north and south of the Alps. A sufficient range of findings and documentation is available for the period after the early 16th century. Pieter Janssens Elinga’s painting of a “Reading woman” brings us into a living room in around 1670 (Fig. A 5.7, p. 38). Sun shines through the upper window into the room. The reading woman, who has placed a chair by the window to gain more light, is protected from the gaze of the curious by the closed shutters covering the lower half of the window. The windows have the diamond-shaped panes typical of the period in northern Germany and the Netherlands. Bands of diamond panes at the top owe less, however, to decorative ornamentation than to the potential for making use of smaller pieces of valuable glass. The early windows that 14th and 15th-century paintings attest to have, however, not been preserved as originals, because they no longer fitted in with changing ideas of domestic comfort. They were replaced, perhaps destroyed or rendered unusable by use and wear and tear. Findings of original early 16th-century objects confirm the details about windows shown in paintings. Such original finds also prove that from the late 17th century, painted windows often no longer represent actually existing contemporary windows. Windows had become a purely artistic motif [23], so they can no longer be precisely assigned to a specific period.

A 2.15

A 2.16

Materials The oldest wooden windows preserved in secular buildings in southern Germany date from the early 16th century. They are all made of oak and varnished with oil. Their fittings consist of finely contoured corner angles, support brackets and forged and coiled sash fasteners and knobs (Fig. A 2.18). Before 1700, the sashes were flush in the frame rebate and flush with the frame inside and out. These A 2.17

17

The historic development of the window – from its origins through to the early modern era

ical of that period for all the German-speaking lands as well as neighbouring countries such as France and Poland. Windows of this era were largely similar in materials and construction, although their glazing varied. There were also few regional differences, such as variations in window size or segmentation and the addition of sliding or pivoting ventilation sashes. Windows documented in drawings from this period are dealt with in the section on “Local discoveries” (p. 20f.).

The “gold of the Middle Ages”

A 2.18

windows were rendered draughtproof by planing the sashes at the back and press fitting them into the frame rebate. Depending on the weather and time of year, the wood’s swelling and shrinking would have made opening and closing the sashes problematic. For the next 200 years until the beginning of the Baroque period, this type of window remained the technical building standard, until demands for better sealing and functionality led to the development of windows with reveal frames. From the 18th century, windows were, apart from a few exceptions such as at the Orangerie of Schloss Schwetzingen, made with a rebate. The only difference between these and the few flush windows made after 1700 is the honeycomb-shaped panes used instead of the formerly customary round bullseye or crown glass panes of the windows of 200 years before. Although the construction features described were concentrated in southern Germany, they are regarded as typ-

A 2.19

18

The history of glazed windows is also the history of glass. Glass, the “gold of the Middle Ages”, shaped the development of the window well into the 20th century. The most expensive of all the materials used to make windows, with its unique natural properties of airtightness, transparency, translucency and fragility, glass is a building material but also a metaphor for clarity, purity and transience. Until well into the modern era, glass production was “arcane” knowledge reserved for the powerful few. In the second half of the 19th century, the size of windows in Parisian houses was still used as basis for levying taxes. As mentioned above, the oldest panes of flat glass known to us are Roman. The glass used in the Roman province of Germania was a cast glass installed in buildings with special uses, such as baths. These cast windowpanes were of moderate quality, not transparent, only translucent. Pieces of them have been found along the Rhine and Mosel rivers. In the centuries after the decline of the Roman Empire, glass was used exclusively in sacred

A 2.20

buildings, with sources referring mainly to French and English cathedrals. Of all the Gothic cathedrals, Chartres has the largest stock of preserved original windows, with around 6,700 m2 of glass windows made between 1215 and 1240. Glass was comprehensively used in the construction of ecclesiastical buildings only from the 13th century and in large cathedrals (Fig. A 2.21). Definitive findings from Germany include the older “Bible windows” in Cologne Cathedral (1250/1260). Such Bible windows were always the highest-placed windows and have been preserved only in a few churches, such as those in Cologne, Strasbourg and Esslingen. The important and comprehensive stock of 400 panes of late 13th and early 14th century window glass in the three Esslingen churches and their glass painting brings the order of the medieval world to life and testifies to the glass painters’ high levels of technical and artistic skill [24].

Glass production – the “arcane knowledge” of a powerful few There are various methods of manufacturing glass, but all demand high levels of artisanal skill, experience and knowledge. Benedictine monk Theophilus Presbyter gives an early description of glass manufacture in his early 12th-century collection of texts, the “Schedula diversarum artium” [25]. It describes processes known since the 7th century B.C. that Roman glassmakers had also practised. Glass-blower’s pipes were always used in this production because that was the only way of producing transparent panes at the time.

A 2.21

The historic development of the window – from its origins through to the early modern era

In the cylinder blowing process, the glassmaker repeatedly takes a viscous glass mass out of the smelter with the pipe and blows it first into a sphere, then into a cylinder. Because of the size of the glass balloon, this process is carried out in the so-called “swing pit”. The balloon is constantly turned in a form, which gives it its characteristic surface structure. This type of surface structuring gives the cylinder support and form during blowing. Before further processing, the two ends /caps are cut off and the cylinder is separated with a hot iron and unrolled in a roller kiln at about 750 °C, bent over wood, stretched and “ironed” smooth with a wooden tool to create flat panels of glass (Fig. A 2.24). Until the end of the 19th century, almost all panes of glass were made using this technique, including the 84,000 m2 of glass for the Crystal Palace at the Great Exhibition in London, which was built in 1851. This elaborate and laborious process was subsequently simplified by a method that used compressed air, which meant that cylinders up to 12 metres long could be drawn up out of the smelter. This was a precursor of the drawnglass technique, which emerged around 1870 and draws the glass mass directly in a flat band straight up out of the smelter. In 1904, the Belgian engineer Emile Fourcault registered this process as a patent for manufacturing glass by machine [26]. The second main production technique in use since the Middle Ages requires even greater artisanal skill to produce panes of crown glass. A roller kiln is not required and a sufficiently experienced glassmaker can make panes up to 120 cm in diameter using a centrifugal process. Fig. A 2.25 shows the production of a pane of crown glass. The first glassmaker takes up the glass, blows it into a sphere

and rolls it into a cylinder. A helper takes the pipe, forms the glass into a pear shape and hands it on to the blower. The blower heats the glass, blows it more and flattens it into a disk. A helper then breaks it off the pipe and attaches it to a solid punty. The resulting hole is enlarged to form a bulge. After reheating, the glassmaker spins the glass, still soft from the kiln, to form a disk before depositing it on a sand bed. Finally, the punty is removed in an annealing kiln, leaving a characteristic thickening in the middle of the pane that is usually remelted. Crown glass panes could never be worked in one piece. Depending on the glass’s quality, they could be divided into diamonds and squares. The “crown” at the centre of a pane of crown glass was for a long time erroneously referred to as a “bullseye”. Because it was just a thick lump of glass, it was usually remelted [27]. Diamond-shaped, square and bullseye panes of glass were framed by lead rods and combined to make a pane until well into the 17th century. Only in the late 17th century were wooden window bars increasingly used. Bullseye panes are made in a very similar way, but spun until the panes reach the desired size. A small amount of the molten glass is taken out of the kiln on a crown glass pipe and shaped into a bubble. The glass-blower then attaches the viscous mass to a punty and constantly rotates it to form a disk 8 to 12 cm in diameter. In the 13th century, a method for making disks with a diameter of up to 28 cm was developed that left no marks from tools on the disk and produced a uniformly thick pane. The glassblower blows a shape like an Erlenmeyer flask.

A 2.22

Cutting off the floor of the “flask” produces a “plate” from which the required glass format can be cut [28]. In his “Geschichte des Deutschen Glashandwerks” (History of German Glazing), Franz Lerner reports that German glaziers were mentioned for the first time in the 9th century. Ludwig der Fromme and Karl der Kahle remunerated these artisans for undefined services. In this period, a glazier was someone who understood the art of glass production as well as the processing and painting of glass [29]. The earliest glassworks in Central Europe were founded in the 11th century and it is assumed that they worked exclusively for monasteries and churches. The first German guilds are documented in 1156 in Cologne. The first, probably cast-glass panes were diamond-shaped with an edge length of 6 to 8 cm and were joined together with lead rods to form a windowpane. The fast developing increased demand for panes was met by both

Flush 1

Rear-planed

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16th century window fittings Virgin and Child from the Book of Hours of Folpard van Amerongen, 1450–1460, Malibu (USA), Jean Paul Getty Museum Lucas Cranach the Elder, “The Ill-Matched Couple”, 1532, Stockholm (S), Swedish National Museum “Emperor window” in Strasbourg Cathedral (F) 13th century Konrad Kyeser, Frauenbadehaus (Women’s bathhouse), miniature, late 14th century, Zülpich (D), Museum der Badekultur Flush window with rear-planed rebate Steps in cylinder glass blowing Steps in producing a pane of crown glass

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8 4 6 9 A 2.24

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The historic development of the window – from its origins through to the early modern era

a

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bullseye and crown glass panes with distinctly concentric, irregular structures that were not very even or transparent. These panes, more translucent than transparent, were often coloured a greenish yellow by impurities in the raw glass mass. In southern Germany in particular, bullseye and crown glass panes were replaced by honeycomb-shaped panes after the late 17th century and from the mid-18th century by square panes or other innovations. In the 14th and 15th centuries, glazed windows were almost exclusively diamond-paned, although there were variations, as Konrad Kyeser’s late 14th century miniature of a women’s bathhouse shows (Fig. A 2.22, p. 19). The bathhouse’s open windows enable people to see both in and out. In the adjoining room, perhaps a room for warming up and relaxing in, the windows are, unusually, glazed with panes of crown glass, the production of which has been documented in the early 15th century. In the 16th century, bullseye and crown glass panes predominated, although a few square panes were also installed. From the early 18th century, honeycomb-shaped panes predominated for a few decades, until they were replaced from around 1750 by increasingly large square panes segmented by leaden or wooden bars.

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Breaking out of darkness

Local discoveries

Around 1500, the “Dark Ages” began to decline and a new spirit of optimism took hold. Initially and to a great extent, this resulted in the opening of exterior walls of certain rooms with prominent functions in grand, prestigious buildings with circumferential rows of windows. Dwellings became light and bright. Within a few decades, windows developed and, apart from some functional aspects, they are largely unchanged today. Materials used included durable oak wood, segmented glazing and decorative iron opening and closing fittings; often, small panes or pivoting sashes were added for ventilation. From 1500, glazed windows became standard in city buildings, although just a few decades earlier they had been the exception. Glazing became the rule, especially in public buildings. Only buildings used temporarily, such as the Tanzhaus in Augsburg, had large window openings but no glazed windows. As a depiction of the Tanzhaus from 1500 shows, the wooden shutters attached to the sides of the windows are open to provide light and ventilation despite the cool weather.

Enough early 16th-century windows have been found to allow definite statements on windows to be made, and the author alone has documented around 50 buildings with windows from the period before 1700. Often, these are individual windows that were not included in earlier building works for various reasons and so not replaced. Findings from the first half of the 16th century are fragmentary but significant and confirm the information from archival sources. In the castles at Heubach and Köngen, windows from the early 16th century when the castles were built have been retained, although without their original glazing. A window dating from 1506 has been identified in the Überlingen Gasthaus Krone (Fig. A 2.26). With its size and segmentation, materials and construction, and fitting and glazing details, it is almost identical with the window depicted by Lucas Cranach the Elder in 1532 (Fig. A 2.20, p. 18). This is also the case with the windows in the Hilchenhaus in Lorch, where, during the most recent renovations in 2013, three windows dating from the house’s construction in 1546, unfortunately without their original glazing, were restored. Late 16th-century windows, some with original glazing, have been retained in the former Chorherrenstift (Convent of Canons) in Herrenberg

The historic development of the window – from its origins through to the early modern era

a

A 2.26

Reconstruction of windows from the Gasthaus Krone, Überlingen (D) 1506 a Interior view b Horizontal view c Vertical view A 2.27 Window in the former Convent of Canons (Chorherrenstift), now the Evangelisches Dekanat, Schlossberg 1 in Herrenberg (D) 1577 The row of windows, sophisticated for its period, extends across the entire exterior wall. There are pivoting shutters, an additional ventilation sash and shutters attached to the exterior. Additional windows were installed in the early 20th century. a Exterior view b Interior view c Horizontal view d Vertical view e Photo of the windows, which have been preserved in situ

(Fig. A 2.27), in Weikersheim Palace, in the old Spital (infirmary building) in Schwäbisch Gmünd and in the Stadtarchiv (city archives building) in Überlingen. In Herrenberg, a row of four windows in the Renaissance room from 1577 has been documented. These windows, apart from a few repairs, represent a particularly authentic and complete document that is still in its original place. Around 50 % of the bullseye panes typical of the period are still preserved in their original condition. These are double windows typical of the period that were improved by the installation of horizontally sliding ventilation flaps in the lower sashes. This group of windows also features the only sliding shutters in Baden-Württemberg. The window bays’ protected position in the northern facade directly under the eaves facing away from the city and the additional exterior windows installed in the early 20th century contributed significantly to maintaining the old windows in good condition.

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Further significant finds have been made in the Frauenberg Monastery in Bodman on Lake Constance and in Nördlingen (Fig. A 2.28, p. 22). The largest contiguous discovery of 17th-century windows has been made at Salem Abbey on Lake Constance, which was rebuilt in 1697 and has 80 high-quality windows dating from that period (Fig. A 2.29, p. 23). e

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The historic development of the window – from its origins through to the early modern era

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This chapter seeks to trace the development of the window and its glazing until the end of the 17th century, based on the few available sources and the author’s own documentation and observation of buildings over many years. Only over the last two decades has it become clear how rarely windows more than 300 years old can still be found. The author wants to open readers’ eyes to the small range of original building elements and their high value as witnesses to history and heritage. In contrast, significantly more windows from the period after 1700 have been preserved, and comprehensive publications on them are available. The full range of materials used, ranging from wood and metal through to plastic, various types such as casement and composite windows, and windows with various functions ranging from those with sliding and turning and pivoting sash windows will be described in more detail in the chapter on “Working with historic windows” (p. 148 ff.). Notes [1] Selbmann, Rolf: Eine Kulturgeschichte des Fensters: von der Antike bis zur Moderne. Berlin 2010, p. 40 [2] 1 Moses, 6, 16 [3] Kästner, Erich: Die Schildbürger. Zurich 1954 [4] Ficker, Friedbert: Gerhard Bersu und die vorgeschichtliche Hausforschung. Zum 40. Todestag des Wissenschaftlers. In: Sitzungsberichte der Leibniz-

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Sozietät, Vol. 76. Berlin 2005, p. 167 [5] Probst, Ernst: Rekorde der Urzeit. Munich, 1992 [6] www.spiegel.de/wissenschaft/mensch/steinzeitbau-archaeologen-entdecken-aeltestes-haus-grossbritanniens-a-711349.html [7] Ossenberg, Horst: Das Bürgerhaus in Baden. Tübingen 1986, p. 23 [8] Dodt, Michael: Die Thermen von Zülpich und die römischen Badeanlagen der Provinz Germania inferior. Bonn 2003, p. 81f. [9] Komp, Jennifer: Archäologische und archäometrische Untersuchungen zur Glasherstellung im Rheingebiet. Berichte aus der Geschichtswissenschaft. Herzogenrath 2009 [10] Archäologie in Rheinhessen und Umgebung e. V. (pub.): Berichte zur Archäologie in Rhein-Hessen und Umgebung. Mainz 2009, p. 28, 31, 37 [11] Eckhardt, Karl August (ed.): Die Gesetze des Merowingerreiches 481–714. In: Germanenrechte, Vol. 1/1. Weimar/Böhlau, 1935, p. 156 –174 [12] Schneider, Jürg Erwin; Kohler, Thomas Michael: Mittelalterliche Fensterformen an Zürcher Bürgerhäusern. In the “Zeitschrift für schweizerische Archäologie und Kunstgeschichte”, 40, 1983, p. 157–180. [13] ibid. [14] Frank, Lorenz: Zur Frage des Auftretens großer Fensteröffnungen an romanischen Profangebäuden. In “Fenster und Türen in historischen Wehr- und Wohnbauten”. Stuttgart 1995, p. 32 – 40 [15] Handzel, Josef: “Von erst in der grossen Stuben” – Adlige Sach- und Wohnkultur im ausgehenden Mittelalter und der frühen Neuzeit im Gebiet des heutigen Österreich. Vienna 2011 [16] Descudres, Georges et al.: Das Haus “Nideröst” in Schwyz, Archäologische Untersuchung 1998 – 2001. In “Mitteilungen des historischen Vereins des Kan-

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tons Schwyz”, Vol. 94. Schwyz 2002, p. 209 – 277 [17] Gollnick, Ulrike: Das spätmittelalterliche Haus Herrengasse 15 in Steinen SZ: eine baugeschichtliche Untersuchung. In “Mitteilungen des Historischen Vereins des Kantons Schwyz”, Vol. 101, 2009, p. 17– 47 [18] as for Note 12 [19] ibid. [20] ibid. [21] Steuer, Heiko: Freiburg im überregionalen Vergleich: Das Bild der Städte um 1100. In: Freiburg 1091–1120. Neue Forschungen zu den Anfängen der Stadt. Reihe: Archäologie und Geschichte, Vol. 7. Ostfildern 1995, p. 79ff. [22] Corsepius, Katharina et al.: Der Blick durch das Fenster – Fernblick oder Innenraum. In “Sonderdruck aus Opus Tessellatum – Modi und Grenzgänge der Kunstwissenschaft, Festschrift für Peter Cornelius Claussen”. Olm 2004, p. 17– 31 [23] Sonntag, Stephanie: Ein Schau-Spiel der Malerei, Das Fensterbild in der holländischen Malerei des 17. und 18. Jahrhunderts. Munich / Berlin 2006, p. 45 [24] Becksmann, Rüdiger: Von der Ordnung der Welt: mittelalterliche Glasmalereien aus Esslinger Kirchen. Esslingen 1997 [25] Brepohl, Erhard: Theophilus Presbyter und das mittelalterliche Kunsthandwerk. Cologne / Weimar / Vienna 1999 [26] Glashütte Lamberts (Pub.): Die Kunst Glas zu machen. Waldsassen (company brochure) [27] Benz-Zauner, Margareta; Schaeffer, Helmut A.: Glastechnik Flachglas. Munich, 2007 [28] Trumpf, Rainer: Glas im Bauwesen. In “Fenster im Baudenkmal”. Berlin 2002, p. 59ff. [29] Lerner, Franz: Geschichte des Deutschen Glaserhandwerks. Ein Überblick. Schorndorf 1950

The historic development of the window – from its origins through to the early modern era

Parts of this chapter on “The historic development of the window – from its origins through to the early modern era” have already been published in “Huckfeldt, Tobias; Wenk, Hans-Joachim (eds.): Holzfenster – Konstruktion, Schäden, Sanierung, Wartung. Cologne 2009, p. 13 –32”. Hermann Klos and the publisher would like to cordially thank the Rudolf Müller Verlag for their kind permission to reproduce this work here and for the good cooperative relationship.

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Reconstruction of a window, measurements as accurate as possible, taking deformations into account, Mötzelsches Haus, Hindenburgstrasse 20 (now Polizeigasse 20) in Nördlingen (D) 1630 a Exterior view b Interior view c Horizontal view d Vertical view and fittings Windows in Salem Cistercian Abbey (D) a Interior view and sections of a window from the period of the Abbey’s reconstruction in 1697. Inventory: a window typical of its period, in oak wood, flush construction, tin-plated decorative fittings and partly preserved glazing with honeycomb-shaped panes from the time of its construction as well as later square panes b Crossbars made of lead rods with a finial, window detail with later square panes, probably 18th century c Window from the period of the Abbey’s reconstruction in 1697 with the distinctive features of the windows of this time: flush-closing oak sashes, small-paned leadlights and elaborate, hot-dipped tin-plated fittings b

c

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Designing facade openings Jan Cremers

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Openings in buildings meet a comprehensive range of functional requirements. Apart from their objective necessity, their order and characteristics contribute significantly to a building’s design impact, regardless of the designer’s intentions. They are an important criterion in classifying a building in its construction history and socio-cultural context and enable us to draw conclusions about its importance. This lends openings an aesthetic and cultural as well as a metaphoric dimension, and in specific chronological and local contexts, they can become a central issue in architecture.

The relationship between a building’s openings and its envelope This book focuses on openings in a building’s envelope, which allow for an “opening” of the building, as described in the introductory chapter (p. 8ff.), and establish a link between inside and outside space. These openings include windows, exterior doors and many other elements, such as shutters or ventilation openings, with and without closure or permeable structures for ventilation, views inside and out, and lighting. A building envelope’s open or openable areas are usually limited to a series of slits or holes or a penetrable area (Fig. A 3.3). In extreme cases a building’s entire envelope can form a rigid, permeable structure (Fig. A 3.4) or be completely opened (Fig. B 3.56, p. 139). Mutable openings in building envelopes have great significance and exist in almost every building. If they are closed, you often cannot tell or can only tell with difficulty whether an opening element can be opened at all. This chapter will deal with the design of facade openings in various states of opening and with translucent but unmoving elements such as window glazing and openings that are visible only when they are open (Fig. A 3.1). Openings structure and order a facade. The history of construction shows that the order, proportions and characteristics of individual openings and the treatment of other facade

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elements are often subject to an ordering principle and an overarching design intention. They follow a traditional facade order whose significance is usually coded (Fig. A 3.7, p. 26), so the opening becomes a design motif and part of a building’s style (e.g. Gothic lancet windows). In many cases, the functional aspects of a building’s usage and construction and legibility of its tectonic structure were regarded as of secondary importance (and this is partly still the case). Proportion systems for entire facades, to which the arrangement and layout of openings are subjected, are issues that have persisted in architecture through various epochs. Giuseppe Terragni, for example, an adherent of Italian Rationalism, strictly rejected Historicism, yet his architecture made use of the order and rhythm of explicitly Roman models [1]. Terragni sought satisfactory design solutions by carefully adapting the proportions of individual elements to each other and to the overall surface (Fig. A 3.8, p. 26). His buildings’ uses are not communicated to the outside world, and their importance is not formally enhanced by additional elements such as pediments or cornices. Even where there is no or no identifiable overarching system of proportion, the form of opening elements is always related to the facade’s closed surface. Openings can be treated as individual elements or subordinated to a building’s overall appearance by means of rhythm, sequence and repetition. Their design impact

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Glazing flush with the exterior; individual openings visible only when windows are open, university library in Utrecht (NL) 2004, Wiel Arets Achitects Solid wall with freely placed openings, ZollvereinKubus, Essen (D) 2006, Sanaa Permeable structure with integrated windows, Juna Mahal Palace, Dungarpur (IND) 14th century Permeable surface structure, Kolumba Kunstmuseum des Erzbistums, Cologne (D) 2007, Peter Zumthor Envelope surfaces retreat behind window surfaces, 16th and 17th-century guild houses on the Grote Markt in Antwerp (B) Decorative facade, independent of the building behind it, 13th century town hall in Stralsund (D)

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then lies in the sequence of the rhythmic interaction of opening elements, and there is less emphasis on individual elements. Examples of buildings whose facade has been “completed” by painted or modelled images, in other words by “fakes”, demonstrate this especially clearly. Conversely, a building’s overall appearance may be shaped by a single or several different opening elements that are not directly connected by common features or subordinate to the surface. This kind of approach, however, does not exclude an overarching design motif for a facade, with a complex frame of reference of metaphors and allusions. This is shown by the example of the Vanna Venturi House by architect Robert Venturi, who has dealt intensively with this issue both in his work and as one of the major theoreticians of postmodernism (Fig. A 3.10, p. 27). There are two possible extremes in the relationship of a wall surface to an opening: On the one hand, an opening can merge into the surface and be completely subordinate to it, be “camouflaged”, barely visible and seen only when it is open or not at all. On the other hand, the closed surface can retreat behind single or repeated opening elements in the overall design until it almost completely disappears (Fig. A 3.5). Openings in a facade generally reveal details about a building’s inner structure, access and usage. They communicate a building’s

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storey structure and relative ceiling heights on its exterior and help us gauge its height. The division of a building into storeys and the corresponding height of windows can also serve as a basis for a design order. Opening elements can be specifically arranged to conceal connections with usage or spatial structure and manipulate perception. Mezzanines can have this effect because their subordinate small openings may lead them to be perceived from the outside as part of a main storey. In the past, this concealment was often used not just for design reasons, such as proportion or the (assumed) prestige of high spaces, but to avoid imposts associated with additional storeys proper. The arrangement of openings often makes the position of staircases in a building and thus the vertical access legible. Access can also be effectively marked by overlying or adjoining openings. Other fundamental design aspects result from the construction implementation and material used. Openings are an element of a building’s tectonic structure and can contribute to its legibility or deliberately obscure it, as Fig. A 3.2 shows. Here, openings are cut seemingly arbitrarily in a homogeneous solid wall to create a punctuated facade. Only structural requirements limit the possibilities in terms of the position, size and arrangement of openings. Some architects, such as Louis Kahn, have used structural elements and

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tectonics to create an architecture that almost celebrates the openings in a brick wall with carefully detailed lintels and discharging arches (Fig. A 3.14, p. 27). Similar clarity is found in historic half-timbered buildings, whose exterior walls are divided into linear load-bearing and bracing elements and intervening areas. The uncovered framework of a half-timbered building leaves no doubt about where openings can be created and how big they can be.

The proportion of opening to space Openings are closely connected with the space on both sides of a building envelope. Complementing the envelope’s two-dimensional flatness, they denote a third dimension, depth, and seem to extend the space [2]. This relationship is expressed in various ways. An opening element itself can be spatially expansive. A simple example of this is the traditional casement window. Complex spatial configurations, such as those in Antonio Gaudí’s Casa Batlló (Fig. A 3.13, p. 27) or Louis Kahn’s Phillips Exeter Academy library (Fig. A 3.18, p. 28), are also possible. Another alternative are openings that expand beyond the envelope either inwards or outwards, as a bay, exterior vestibule, roofed staircase, front portico or projecting window (Fig. A 3.12, p. 27). An opening element’s position in the

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Designing facade openings

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reveal, in the middle, flush with the exterior or the interior, projecting inwards or outwards or protruding, can obscure or emphasise a wall’s spatial dimension. This becomes particularly clear with so-called poché [3] or voluminous walls [4] (Figs. A 3.11, A 3.16 and A 3.17, p. 28). Deeply inset windows, seen in the light of the sun, increase a facade’s plasticity due to the clear shadows they throw. In contrast, windows flush with an exterior reduce the wall’s spatial dimension, so the facade looks flat by day. At night, when artificial light clearly articulates the reveal and openings, this effect is reversed. The mutability and moveability of opening elements, especially their type of movement and direction of opening, also deter-

mine their relationship to the space. Pivoting windows that open outwards, for example, make a building “reach out” into exterior space in a gesture that is perceived as inviting. This effect is much more marked when elements are seen obliquely and is enhanced by dark shadows on the facade surface in sunlight (Fig. A 3.1, p. 24). Similar design outcomes can be achieved by exterior additions to building openings such as elements for screening the sun, deflecting light, offering shade, screens and temporary insulation etc. Openings are also a means of separating structural elements or individual volumes within a building or between buildings. Areas

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Designing facade openings

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that can be separated or connected increase a floor plan’s flexibility. In Shigeru Ban’s “wallless house” an interior sliding wall can temporarily become an openable exterior envelope (Fig. A 3.19, p. 29). Arranging opening elements in several successive, spatially separate layers creates complex intermediate zones that flexibly combine the qualities of interior and exterior space (Fig. A 3.15, p. 28). Placing several openings in succession makes the space of a staggered or sequential structure legible from a single standpoint. The treatment of openings can also reveal the fundamental relationship between a building and its facade. Decorative or false facades like that of the Stralsund town hall may be

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designed largely independent of the structures behind them (Fig. A 3.6, p. 25). Robert Venturi describes buildings with facades that are largely or entirely detached from the cubature of the structure behind them for representational purposes and seem merely added on, as “decorated sheds” [5].

Designing openings and the surrounding envelope

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In designing building openings, the opening element itself and surrounding surface must be taken into account. As well as the basic issues of the “hole in the envelope” and “closure of the

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Renaissance facade of the Palazzo Rucellai in Florence (I) 1458, Leon Battista Alberti. Bays divided by flat pilasters in the three classical orders (Doric, Ionic and Corinthian) Analysis of the proportions of the south-western facade of the Casa del Fascio, Como (I) 1936, Giuseppe Terragni Dissolution of spatial boundaries, recessed windows, Villa Tugendhat, Brno (CZ) 1930, Ludwig Mies van der Rohe Different opening elements follow an overarching design principle: Vanna Venturi House, Chestnut Hill, PA (USA) 1964, Robert Venturi Openings in a voluminous exterior wall (poché wall), Einstein Tower, Potsdam (D) 1922, Erich Mendelsohn Opening elements project out of the surface and become physical-spatial objects, Neuer Zollhof, Düsseldorf (D) 2002, Richard Gehry Complex spatial arrangement of opening elements with organic forms, Casa Batlló, Barcelona (E) 1877, Antoni Gaudí Openings reveal a building’s tectonics, Indian Institute of Management Ahmedabad (IND) 1974, Louis Kahn

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opening”, other design elements such as edging, reveal, window sill, architrave, lintel, discharging arch and protection from weather are important in creating a plastic design effect on a building envelope. Such elements have often developed out of historic local structures, so they may have a purely decorative character (Fig. A 3.20). Edgings, for example, (borders made of wood, stone or plaster, offset by structure or colour) a simple form of jambs, developed out of the architrave. They can project out of a wall’s surface, be deeply embedded in it or be marked only by a different colour. Dispensing completely with edgings gives an opening the look of a frameless hole in a dominant surface. An opening’s format and proportions are mainly determined by the possibilities that the building’s load-bearing structure allows for. They also shape the perspective of views. A tall, upright window (“porte-fenêtre”) offers very different views from those provided by a horizontal panorama format. Extensive horizontal formats have only become possible with the advent of steel and steel-reinforced concrete structures. Le Corbusier’s Villa Savoye shows these typical horizontal “fenêtre en longueur”. The smooth exterior walls of the soaring upper storeys project out over the support level,

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making building-wide openings possible. Its window elements have dark frames and, together with the glazing, merge into the facade (Fig. A 3.21). An opening’s segmentation defines the relationship between planar (e.g. glazing) and linear (e.g. frame and crossbar) elements, as does the combination of various fixed, mutable and moveable elements in the surface (e.g. opaque ventilation flaps next to fixed glazing). Small panes of glass were once a strict technical and later an economic necessity for a long time (see also “The historic development of the window – from its origins through to the early modern era”, p. 12ff.), but now huge contiguous, undivided glass surfaces can be installed. This opens up new design possibilities but often turns out to be problematic for construction in a historic context. Internal structuring in depth (layers and shells) may involve a combination of different elements (e.g. interior curtains, window sashes, opaque sashes, sun screens, glare screens) as well as the position of the opening element in the building envelope. Material, colour, form and the proportion of linear and planar elements but also reveals and other parts of openings (e.g. windowsills) decisively shape a building’s overall

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appearance. Delicately profiled frames and crossbars, seen close up, increase a facade’s plasticity and decorative effect due to the sophisticated play of light and shadow that they create. Many manufacturers produce various types of profiles, ranging from rightangled, memberless, sharp-edged profiles through to historic-looking ones with rounded corners. The current trend is for slender frames, undivided large areas of glass and flush components. Universal design solutions for different types of openings are also being developed, such as large sliding doors, inset and roof windows and skylights, as well as standard windows. The detailed design of linear elements and their positioning, such as the arranging of frame corners (e.g. frames with rounded inner corners), and transitions between surfaces, for example, from frame to glass, are important issues in this context. Appropriately designed and coordinated fittings complement a structure’s appearance, and not only in historic buildings. Other components positioned in front of or behind opening elements (horizontal sliding elements, folding shutters etc.) often play a major, sometimes even dominant role in a facade’s overall design effect. Using translucent, reflecting and permeable structures and

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materials in opening elements, especially in combination, can give rise to diverse and complex design options. An element’s appearance will vary greatly depending on the weather and light situation [6]. Designs can also be modified by using various combinable surface treatments, especially in glazing. Its transmittance and reflectivity can be adjusted across large areas through the use of coloured glass or glass with coloured reflections, coatings and (partially) mirrored and printed surfaces (see “Coatings”, p. 89ff.). The quality of the glass itself is also significant in this context. Some historic buildings still have old glazing, whose irregularities (e.g. surfaces not planar, air bubbles, impurities in the glass and areas of reduced transparency) have a special effect, particularly on the glass’s reflectivity (Fig. A 3.26, p. 31).

Opening as symbol, opening and ornament Openings in a building envelope are also symbolic and can be used as allegories or overarching signifiers, thereby gaining a new meaning, e.g. in a religious or mythological context (Fig. A 3.25, p. 31). The image of a face is frequently referred to in the context of facades, with windows as eyes (Fig. A 3.22,

p. 30). This metaphor works just as well the other way around, with openings like pupils gazing out from inside a building (see “Windows and doors in art and culture”, p. 32ff.). Communicating via a facade is a central topic in the history of construction. Building envelopes have always been part of cultural tradition and still tell stories, large and small, today, especially through images, sculptures,

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Openings at various depths in the envelope, National Assembly Building (Jatiya Sangsad Bhaban), Dhaka (BD) 1982, Louis Kahn A 3.16 House with voluminous walls, floor plan detail, Cologne (D) 1996, Oswald Mathias Ungers A 3.17 Interior with a view of voluminous walls, Cologne (D) 1996, Oswald Mathias Ungers, floor plan detail A 3.18 Workplace by a window, Phillips Exeter Academy Library, Exeter, NH (USA) 1972, Louis Kahn A 3.19 Interior sliding wall as openable exterior envelope, Wall-Less House, Nagano (J) 1997, Shigeru Ban A 3.20 Architectural language of an opening, in this example a Renaissance window A 3.21 Dark-framed windows form a contiguous row of windows (Fr. “fenêtre en longeur”), Villa Savoye, Poissy (F) 1931, Le Corbusier

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symbols and text. Technical devices are now increasingly being used for this purpose. The targeted use of artificial lighting, projections and display technologies, as well as interactive control using smartphones, makes it possible to create modern media facades whose changing appearance carries a flow of varying information. Facade openings play a special role in window animations. By controlling interior lighting or LEDs installed in window frames, individual opening elements in a grid facade can be made to look like the changing pixels in a digital image.

tecture. Openings are an essential means of spatial organisation and offer opportunities to create complex ambiguity. Depending on a structure’s spatial concept, glass may be used as an occlusive material in a partition primarily for its planar quality or for its transparent property. While an opening that dissolves or offers an option for dissolving the spatial boundary between inside and outside space literally entails transparency or translucency (Fig. A 3.9, p. 26), the simultaneous perception of inside and outside creates transparency in a figurative sense.

Where there is a focus on a facade’s decorative effect, openings themselves and even the surfaces around them can become ornamental. For the entrance to Olivetti’s showrooms in Venice (Fig. A 3.27), Carlo Scarpa highlighted the opening as part of the facade surface and interior by strikingly clamping individual architectural elements between consistent ornamental elements [7].

According to Bernhard Hoesli, transparency exists “wherever in space there are places to which two or more frames of reference can be assigned – although this assignment remains indeterminate and the choice of possible assigning remains free” [10]. Matthias Loebermann adds to this largely static definition of transparency the aspects of movement and mutability that openings in buildings offer. Movement can also refer to the observer as well as to the change in perspective resulting from a change of position. This topic is a significant feature of historic architecture in Japan and has also decisively influenced western architecture [11].

Openings, transparency and reflection Opening elements can offer transparency, in a purely physical as well as in a material and figurative sense. The Swiss architect Bernhard Hoesli has spoken of the “essential and apparent transparency”, of the “being and appearance of transparency” that largely determine “whether a building is or whether it signifies” [8]. The issue of transparency in architecture has been a subject of theoretical controversy in architecture since the modern era and the 1960s in particular [9]. Discussion has focused on the legibility of architecture through facade openings and on the interaction of floor plans and elevations, i.e. the offset in depth at individual levels – as with a theatre stage – which can be perceived simultaneously from a single standpoint. In this sense, openings allow for diverse spatial relationships by means of superimposition, overlapping, interlocking and especially mutability. Only through openings can the third dimension of space be exploited in its full significance for the purposes of archi-

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In considering the material and construction of openings, the notion of transparency is of interest, especially in the context of a building’s structural characteristics. Transparency can range from complete transmission (opening with no closure – open) through degrees of partial transmission and up to opaque solutions that regulate views in and out and the lighting conditions inside the building. Openings are an essential tool for directing incident daylight. Correctly positioned, they allow the morning sun to shine directly on the altar of a church on the name day of its patron saint. Over the course of a day and depending on weather conditions, they let changing incidental light into an interior (varying intensity, direction, colour of light, proportion of direct / diffuse) and give us a feeling for the passing of time that is completely absent in interiors with no links to the outside.

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Light reflection and transmission are essential effects of all opening closures, including glass. Depending on their angle and standpoint, they can determine what an observer can see. The photometric properties of opening elements (transmission and especially reflection) have special effects on elements’ appearances. Glazed openings look different depending on lighting conditions, the height of the sun, the angle of observation and the environment. On bright days when they are open, they look dark from the outside. When they are closed, reflection gives them a nontransparent appearance (Figs. A 3.23 and A 3.24). Only non-reflecting glass or lots of light behind glazing, e.g. from artificial light, or looking into an illuminated space through glazing, results in physical transparency. At night, the converse is the case: The glazed openings of an illuminated interior look completely transparent from the outside, while closed surfaces between openings look flat and black, regardless of their colour and surface design. Building openings, with their various open and closed states and varying appearance over the course of days and seasons, are of outstanding significance for facades and contribute substantially to the richness of the built environment’s design.

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A 3.25 Notes: [1] Ciucci, Giorgio (ed.): Giuseppe Terragni. Opera completa (Documenti di architettura). Milan, 1997, p. 221 [2] A team of authors from Tokyo Institute of Technology has dedicated itself to this very complex issue in a richly illustrated book – Tsukamoto, Yoshiharu et al.: WindowScape – Window Behaviourology. Singapore, 2012 [3] “Thick, often irregularly formed wall masses that make the space look packed and buffered as if by a padded pocket (French “poché”). […] The mass built as the Poché can also contain space through porosity or as a voluminous wall”. From Janson, Alban, Tigges, Florian, Grundbegriffe der Architektur. Basel 2013, p. 236f. [4] “A voluminous wall has compartments, niches or small secondary spaces between the inner and outer wall surface that not only appear as porosity, but also make the wall into space. It not only borders a space, but its hollow, layering or folding expands the space with its own cavity, softens the space’s boundaries or graduates it in depth.” From Janson, Alban, as for Note 3, p. 248f. [5] Venturi, Robert; Scott Brown, Denise; Izenour, Steven: Lernen von Las Vegas, zur Ikonographie und Architektursymbolik der Geschäftsstadt (Learning from Las Vegas). Bauwelt Fundamente 53, Braunschweig 1979, p. 104ff. [6] Permeable surfaces and structures can also be created by superimposition with various layers of density and interference. Matthias Loebermann coined the term “operative transparency” to describe this. See Loebermann, Matthias, Operative Transparenz. In ARCH+ 144/145, 12/1998, p. 103ff. [7] Los, Sergio: Carlo Scarpa, Essay. Cologne 1993, p. 11ff. [8] For a more precise definition of ideas of transparency in architecture and modern painting, see also Rowe, Colin; Slutzky, Robert: Transparenz, with commentary (1968) and addendum (1982) from Bernhard Hoesli in the 3rd expanded edition Basel / Boston / Berlin 1989, p. 47 (Original edition 1964). This essay can be seen as a reaction to remarks made by Sigfried Giedion on the Bauhaus in Dessau in “Raum, Zeit, Architektur – die Entstehung einer neuen Tradition” (1941), which was a very early contribution to the debate on architectural notions of “transparency”. [9] Colin Rowe and Robert Slutzky explain this by comparing Gropius’ Dessau Bauhaus and Le Corbusier’s Villa Stein (as Note 8, p. 23ff.). “The reality of the deep space is constantly contrasted with allusions to a shallow space (the real and denoted layers of space).” (ibid., p. 29) Bernhard Hoesli in a general comment added, “Symmetry as an ordering principle is exclusive, subordinative and absolute; transparency as an ordering principle allows for more relativity and

opens up a series of potential orders” (ibid., p. 62). The Rowe/Slutzky approach was subsequently critically appraised in ARCH+ 144/145, 12/1998, an issue on the topic entitled “Kommende Transparenz”, in which various authors sought to find a contemporary definition of the term and expand it, and referred to the 1964 essay. Please see also contributions by Nikolaus Kuhnert, Angelika Schnell, Matthias Loebermann and Detlef Mertins. [10] see Note 8, comment by Bernhard Hoesli, p. 49 [11] Loebermann, Matthias: “Transparenz heute”. In ARCH+ 144/145, 12/1998, p. 100ff.

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House with a “face” from the 1958 film “Mon oncle”, Jacques Tati Light and weather conditions greatly influence the optical effect of a building opening. An alienating effect caused by reflection as a design issue, artistic facade design “TransReflex”, west-wing of art museum Kloster Unser Lieben Frauen Magdeburg (D) 2012, Realities:united Symbolic form, opening in a chapel Distorted reflections created by small-scale window glazing Opening and ornamental design, Olivetti Showroom, Venice (I) 1958, Carlo Scarpa

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Windows and doors in art and culture Elke Sohn

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Windows and doors – loci of special design and significance “Windows (from the Latin ‘fenestra’) are openings in walls for lighting and ventilating interiors” [1], explains a German picture dictionary of architecture. Doors are openings that enable people to pass through walls. These definitions may seem dry at first glance, yet they are also revealing. Windows and doors serve our bodies and senses as links between interior and exterior space. The window has long been a popular theme in painting, and not just because it offers visual contact and frames our gaze; it has also become a synonym for a picture. The idea of a picture as a window frame has served art theorists and artists such as Leon Battista Alberti and Albrecht Dürer as a basis and inspiration in the use of details, divisions and perspective (Fig. A 4.1). Doors and windows mark a transition between inside and out. They form links but also barriers. They can be read as central metaphors for elementary issues surrounding transition, within life stories and between life and death and heaven and earth. Windows and doors are not marginal figures in the history of art and culture, nor should they be in designs. An understanding of the wide-ranging cultural significance of windows and doors is essential to their proper planning and design. If you look into the linguistic background of both words in the Brothers Grimm’s German Dictionary, you soon find that the word “window” shares roots with words cognate with the eye and seeing. “Window” is paraphrased with terms to do with the eye, such as the Gothic “augadaurô” [2]. Similar etymology can be found in many languages, whether in the Slavic minimal pair “oko” (eye) and “okno” (window), the English “window” (wind eye) or in the German word “Ochsenauge” (bullseye), a term for a small round window. Traditional German idioms are also full of such comparisons. While you can look out of a high window (look proud), the body itself has also been likened to a house (Na, du altes Haus). In the same way, notions of the door and the mouth belong together. The Baroque poet Friedrich von Logau describes

32

the mouth as the “thür ins haus” or door to the house [3]. The mouth and the spoken word can also stand for a person. The image of the door or portal is often used to represent a house or city [4]. To “go from door to door” is the same as going from house to house. Gates and portals are displayed on coins, seals and coats of arms as the symbols of cities, such as the Holsten Gate, L’Arc de Triomphe in Paris or Brandenburg Gate in Berlin. A portal or gate can be read as a thematic opening to a city or building and a door as an entry to and public face of a house and household.

Doors as transitional space Doors are connected with notions of access and transition and, as mentioned above, with the house and household. They have become emblematic of the self-determined housing of people on Earth and of the possibility of deciding between enclosure and movement outdoors [5]. A door protects the home and property and itself traditionally requires godly protection, which is solicited by nailed-on or buried offerings and special artistic treatment of the door leaf, frame, threshold, support posts and lintel. One trace of such protective “magic” can still be found in the Catholic custom of inscribing the letters C + M + B above the door on the Twelfth Day of Christmas to denote the blessing “Christus mansionem benedicat” (Christ bless this house). Many historic legends surround the space around the door and threshold, such as Luther nailing his theses to the door of All Saints’ Church Wittenberg, and doors feature in countless idioms and stories involving decisions and crucial junctures. Somebody who “kicks down

A 4.1

A 4.2 A 4.3 A 4.4

Albrecht Dürer, Der Zeichner des liegenden Weibes (Artist drawing a reclining woman), woodcut 1538 Robie House, Chicago (USA) 1908 –1910, Frank Lloyd Wright Marcel Duchamp, Fresh Widow, 1920, New York, Museum of Modern Art Sabine Hornig, No. 1 Pfaff, 2003

Windows and doors in art and culture

an open door” can count on complete agreement to a proposal. Unwelcome guests are “shown the door” or even better, “kept from the door”. You enter and leave a house by crossing the threshold. Doors and thresholds in films and literature also have symbolic power. Crucial events in the life of the protagonist Michel in Robert Bresson’s 1959 film “Pickpocket” are connected with doors. Michel decides at the beginning of the film to make his living as a pickpocket. One day he goes to visit his mother after a long absence. His mother’s neighbour, Jeanne, has a key to the old woman’s apartment and opens it for Michel. He is unable, however, to cross the threshold into his mother’s apartment and departs, leaving her some of the (stolen) money. Later, Jeanne places a message on his threshold telling him that his mother is dying. Michel visits his mother and takes his leave of her, which results in him forming a bond with Jeanne and starting out on a new phase in his life. The wanderer in Georg Trakl’s 1915 poem “Winter Evening” has been unable to return home because “Grief has turned the threshold to stone”, but now the interior of the house welcomes him “in pure light glowing”. A winter evening When snow falls against the window, And long the evening bell sounds, For many is the table set And the house well prepared. From their wandering, many Come along dark paths to this gate. In an act of grace, the tree flowers gold Out of the earth’s cool sap Wanderer, enter quietly, Grief has turned the threshold to stone. But see, in pure light glowing, On the table bread and wine.

A 4.3

A 4.2

The window as picture frame – the effects of media Just as it would be short-sighted to regard a picture as a mere image of something, a window is not only an opening that simply offers a view of something. A picture and a window both frame our gaze in a specific way and shape it. Alberti’s grid of threads and Dürer’s frames formed part of a specific system of perspective and turned the gaze back on the observer. In our modern understanding of art, pictures no longer simply represent people or landscapes. Modern painting has freed itself from the mere representation of “reality” and asserted its own means of colour, forms and materials. In his 1920 installation “Fresh Widow”, Marcel Duchamp consistently prevents us from looking through a French window [7]. Instead, he closes the pane with black and focuses on the object (Fig. A 4.3). The closed window does not mean that there is nothing to see, Duchamp tells us, instead we see shiny black leather. His instruction is that we should regularly polish it, in other words, treat it like a window. It has obviously remained one, albeit without

the putative undistorted view – what counts here is the specific seeing in interaction with the window. In a similar way, the empty display windows in Sabine Hornig’s photographs reveal nothing at first glance (Fig. A 4.4). If you look more closely though, you see the space behind the observer reflected in the glass. The display window becomes a projection screen and a layer in a composition of space and image. Even the window glass in an architectural design can, in reality, never be simply transparent. Modern architecture has been characterised not by clear glass and punctuated facades but by the constructed view from inside to outside. In his 1908 Robie House, Frank Lloyd Wright used leadlight windows with stylised ears of wheat (Fig. A 4.2). The windows provide the house’s inhabitants with a view of (putative) nature through an image of nature created by people. Wright used this organic ornament to symbolise the omnipresent laws of nature. René Magritte also repeatedly sought to reveal the illusion of the objective view of landscape and the media effect of the window (Fig. A 4.5, p. 34). The

A 4.4

33

Windows and doors in art and culture

A 4.5

architect’s firm of Diller & Scofidio also did this in their “Slow House” project, in which a screen was placed in front of a panorama window that makes it possible to view a filmed landscape in any desired state, so with sun instead of rain or day instead of night (Fig. A 4.6). The window does not frame a natural image. Instead, the window and the screen, reality and illusion, are interchangeable. The display both replaces our gaze and reconstitutes it. A window can also focus from the outside in, like a camera. Scant details and an absence of the whole inspire our curiosity and imagination. In Hitchcock’s “Rear Window”, observation of the neighbours through the windows opposite begins to replace the protagonist’s own life (Fig. A 4.7). What seems rather tragic here can be seen as a general metaphor for the picture (and the window). In the snapshot and framed moment, the larger story merges into a still life. The elevation of the mundane into the special or even to cult status is a clear element in Edward Hopper’s paintings of brightly lit interiors in otherwise empty, often dark streets and drab land-

A 4.6

scapes (Fig. A 4.8). Their subjects are banal but the illuminated windows bring to his pictures the “grace” and “glow” described in Trakl’s poem. Various rituals in our culture attest to a window’s ability to elevate things into an aura of the sublime as if on a stage. Blessings, judgements and programmatic speeches often have been and are framed by palace or balcony windows. Whereas those thrust out of the light and away from the window fall into obscurity.

The window as boundary The window’s transcendent power has its origins in the early history of housing. What was once just a hole in the roof to let smoke out also guaranteed free flight for the soul of a person who had just died. An extra hatch, a “Seelapalgga” (Seelenbalken – soul’s hatch) was built in traditional Grisons farmhouses for this purpose [8]. A window represented a boundary and the transition from the earthly to the heavenly. The often coloured windows in ecclesiastic buildings symbolise the Divine

A 4.7

[9]. Churches’ traditionally eastern orientation means that the morning sun shining through their windows can epitomise the resurrection of Jesus Christ, who says in the Gospel of St. John, “I am the light of the world. Whoever follows me will not work in darkness, but will have the light of life.” (John 8: 12) In synagogues and in Catholic churches, the concept of “eternal light” reminds believers of God’s constant presence. In our culture, a window can become a projection screen for hope, longing and release in many ways. In the novel “Und im Fenster der Himmel” by Johanna Reiss (1975), Annie, a Jewish girl who has to hide from the Nazis for several years in a room with her sister, is repeatedly drawn to the window, her only visual contact to life outside. The curtain in Adolf Menzel’s “Balkonzimmer” (balcony room) of 1845, gently moved by a breeze, catches the brilliant sunlight and promises a bright summer’s day (Fig. A 4.11). A window represents not only a boundary between the earthly and heavenly, but also the boundary between probity and impropriety, a border zone and weak point between

A 4.5

René Magritte, La Clef des champs (The key of the fields), 1936, Madrid, Museo ThyssenBornemisza A 4.6 Diller + Scofidio, Slow House, 1991 A 4.7 Film still from Alfred Hitchcock’s Rear Window, 1954 A 4.8 Edward Hopper, Nighthawks, 1942, Art Institute of Chicago A 4.9 Gion A. Caminada, Stiva da Morts, Vrin, 2002 A 4.10 Edvard Munch, The Kiss, 1895, Musée Jenisch Vevey A 4.11 Adolf Menzel, Das Balkonzimmer (The balcony room), 1845, Nationalgalerie, Staatliches Museum zu Berlin A 4.8

34

Windows and doors in art and culture

A 4.9

the public and the private. Between the rough life of the street and the domestic morality of the window space, you can find the topoi of the negligent, the forbidden and the seductive. The German Dictionary contains terms of abuse for housewives who neglect their work such as “Fensterhenne” and “Fensterbeiszerin” [10]. Whereas in German, a maiden can be wooed and courted through a window, the French see this more as “faire la fenêtre” – closer to prostitution [11]. Whoever leans too far out the window risks life and limb, while throwing something out of the window is synonymous with extreme wastefulness. In Edvard Munch’s 1895 “The Kiss”, lovers kiss naked in front of a window (Fig. A 4.10).

A new culture of transition As rich and diverse as the stories surrounding windows and doors in art and culture are, it is not surprising that their neglect is lamented in a critical reflection on functionalistic modernity [12]. Reducing them to mere punctuations in the facade and dispensing with the framing and media character of the panorama window risks vitiating the diverse expression of the culture of windows and doors. Since the modern era, doors and windows have run the risk of degenerating to purely functional elements, their design mainly measured in terms of their effectiveness or seen as mere proportional or grid elements in a facade. “The visible form of a window or door […] is in itself not architecture. The very act of looking out through a window or crossing a threshold represents an entirely authentic encounter with architecture. So architecture is action; residing, occupying, penetrating, entering, leaving and making use of things for a range of very different purposes.” [13] Thus the Finnish architect and theoretician Juhani Pallasmaa urged us in 2004 to consider windows (and doors) as important spaces for life and movement and design them carefully. Yet invocations of a newer culture of transition have already been built. Gion A. Caminada,

architect of the “Stiva da morts” (mortuary) in the Grison village of Vrin (2002), dispensed with windows whose sole purpose is for looking out (Fig. 4.9). His mortuary’s few windows, with their obliquely angled sashes, reach into the room and out of it. Their frames’ varying thicknesses and different pane lengths make the perspective seem unfamiliar and limit our view from them. This window design fits in with the space’s introverted atmosphere, lending gatherings of people and their farewells greater dignity. Notes [1] Koepf, Hans; Binding, Günther: Bildwörterbuch der Architektur. Stuttgart 2005 [2] Grimm, Jacob und Wilhelm: Deutsches Wörterbuch. 32 Vols., Leipzig 1854 –1961, Vol. 3, lemma: Fenster. http://woerterbuchnetz.de [3] ibid., Vol. 21, lemma: Thür [4] Pehnt, Wolfgang: Drinnen und Draußen. Splitter und Späne zur Geschichte der Tür. In: Aicher, Otl; Becker, Jürgen; Pehnt, Wolfgang: Zugänge – Ausgänge. Cologne 1990, pp. 7–12 [5] Simmel, Georg: Brücke und Tor. In: Der Tag Nr. 683, Morgenblatt of 15.09.1909 [6] Müller, Klaus (ed.): Lexikon der Redensarten. Niedernhausen 2001 [7] Kunstsammlung Nordrhein-Westfalen (pub.): Fresh Widow. Fensterbilder seit Matisse und Duchamp. Düsseldorf 2012 [8] Simonett, Christoph: Die Bauernhäuser des Kantons Graubünden. Wirtschaftsbauten. Verzierungen, Brauchtum, Siedlungen. Basel 1968 [9] Selbmann, Rolf. Eine Kulturgeschichte des Fensters. Berlin 2010 [10] as Note 2, Vol. 3, lemma: Fensterhenne, Fensterbeiszerin [11] This expression is used, for example, in the erotic tale “Le Signe” by Guy de Maupassant (1886). [12] Reichlin, Bruno: Stories of Windows. In: Bernasconi, Francesca; Franciolli, Marco; Iovane, Giovanni (eds.): A Window on the World. From Dürer to Mondrian and Beyond. Milan 2012, pp. 278 – 291 [13] Pallasmaa, Juhani: Touching the World. In: Frank, Hartmut; Sohn, Elke (eds.): Auf der Suche nach einer Theorie der Architektur. Hamburg 2005, p. 8

A 4.10

A 4.11

35

Solution principles for adjustable openings Peter Bonfig

Building envelopes form a boundary between exterior and interior space and have a protective function and permeable surfaces that allow for the exchange of light, thermal radiation and air, for views in and out, for lighting and ventilation of the interior and for the transit of energy (Fig. B 1.3, p. 51). Various strategies and solutions, which are constantly expanding due to new perspectives, discoveries and technologies, are available for adapting the envelope’s permeability to changing outside conditions and/or user’s wishes. An adaptive building envelope uses self-regulating processes to dynamically change its permeability [1]. It no longer relies on moveable parts that have to be operated, such as window sashes or blinds. The word “adaptive” in its broader sense can be used to cover all strategies that respond intelligently to changing conditions, even if they are not self-regulating. This book focuses on structural components through which the protective envelope opens or can be opened. This section deals with strategies for influencing the permeability of these openings, beyond traditional notions of windows and doors, and systematically describes their functions, geometric aspects, solution principles and diverse manifestations and interpretations. All these openings have one thing in common: They are part of the thermally insulating building envelope, and their primary purpose is to offer partial to extensive opening to dispense with the separation between inside and out for certain periods.

The functions of adjustable openings Building openings fulfil many functions that make partly contradictory demands (Fig. 5.3) and whose hierarchy can vary greatly. Open-

ings’ characteristics can differ and change in response to the demands of low-energy, passive and plus-energy houses. Primary functions

Based on the perspective adopted herein, some of the primary functions of adjustable openings in building envelopes are: • Ingress and egress • Direct contact with the outdoors • Extensive “opening” • The bringing in and out of objects • Ventilation of the interior Enabling people to enter a building and leave it again through moveable structural components is a fundamental requirement of a building envelope. This interface between public and private can also reflect overarching and spiritual aspects that can be expressed by an element’s orientation, size, materials chosen, symbolic elements etc. We use most entrances and exits regularly, but sometimes openings, not just doors, serve very specific purposes, such as enabling escape from a building in case of fire (secondary necessary emergency escape) or access to a maintenance platform. As mentioned in the chapter on “Openings in buildings” (p. 8ff.), building users sometimes feel a need to directly experience the outdoors and outside air through the protective envelope, regardless of its functional practicality. One specific example in this context are large openings that break up the building envelope and blend inside and outside into a single space with no barriers in pleasant weather when the protective functions are not required. Interiors can become loggias, roof areas or airy

A 5.1

36

Solution principles for adjustable openings

terraces (Fig. A 5.2). This creates a spatial continuum between the interior and exterior and offers new possibilities for usage and experiences. In temperate climates with very different seasons, use of such openings is usually restricted to the summer months. Another elementary functional requirement is enabling the bringing in of objects of all kinds. In this case, the frequency of such deliveries (e.g. of a grand piano or a large piece of technical building equipment) will largely determine the type of opening. If a building is designed to provide natural (free) ventilation through its envelope, air must be supplied through appropriate adjustable openings (see “Natural ventilation”, p. 200f.). The goal here is good interior air quality, which is determined by the composition of the air intake (outside air) and the proportion of gases and compounds resulting from usage and the space itself [2]. In the context of hygienic comfort [3], an exchange of air is important for the following reasons: • Supply of oxygen • Discharge of stale air containing a high proportion of carbon dioxide • Discharge of organic odorants • Discharge of vapours from construction materials (e.g. formaldehyde) • Discharge of combustion gases (from heating, cooking, manufacturing processes etc.) • Discharge of moisture • Discharge of other compounds resulting from production processes As well as various gases, solids (e.g. particles) are also brought inside with outside air, and it is becoming increasingly important to limit or check their passage. These particles may include soot particles and dust from industry and transport as well as organic particles or microorganisms such as pollen, fungal spores etc. The undesired ingress of various small animals and insects through openings into buildings must also be prevented or at least restricted. Natural ventilation requires the movement of air, although air does not necessarily have to be moved mechanically (Fig. A 5.4). This movement of air (streams of gas molecules) requires a difference in pressure between inside and outside air as a result of wind and / or thermal updraughts [4]. Ventilation is usually classified into two main types: • Intermittent ventilation (brief periods of ventilation through large openings), and • Constant ventilation (continuous ventilation through relatively small openings). An exchange of air for hygienic reasons is essential if differences in temperature between inside and outside air are connected with an exchange of energy, which can also be a goal of natural ventilation, using air to specifically supply or release heat. Given air’s low heat capacity, the use of energy

exchange for the free cooling of spaces is limited. Continuous ventilation is problematic in buildings exposed to a large range of exterior and interior temperatures for the following reasons: • Continuous discharge of (mainly valuable) heat from the interior • Excessive continuous supply of heat • Draughts due to large differences in temperature Natural intermittent ventilation at night requires active mechanical systems with controls and servomotors. Alternatively, decentralised mechanical ventilators integrated into the building envelope combined with heat exchangers or heat recovery can be used with continuous ventilation. The position and form of adjustable openings in the building envelope are important in assuring an efficient exchange of air. It can be useful to provide different openings for incoming and outgoing air. As well as prevailing wind directions, aerodynamic aspects and phenomena in the building’s environs and openings must be taken into account.

A 5.2 Primary functions

Different cases Regular use

Ingress /egress Special cases, temporary With access to exterior surfaces Extensive opening Without access to exterior surfaces Regular use

Bringing objects in and out

Special cases, temporary

For economic reasons it may be advisable to combine as many as possible of the primary functions mentioned in a single system.

Natural ventilation With mechanical support

Ventilation Additional functions

An opening element can (but does not have to) fulfil other functions, such as, • Natural lighting (use of daylight) and regulation of it • Possibility for visual contact between inside and out • Passive and active energy generation, conversion or storage Combining daylight and ventilation functions in single openings in a way traditionally achieved with windows is not essential and is becoming increasingly irrelevant with the advent of other more effective and energy-efficient building concepts (Fig. A 5.1).

Mechanical, with heat recovery Additional functions For mainly diffuse sunlight Use of daylight For mainly direct sunlight Daytime measures Visual contact Nighttime measures Generation / conversion / storage of energy

Passive systems Active systems A 5.3

A 5.1

SOKA-Bau, Wiesbaden (D) 2004, Herzog+Partner, innovative facade concept with the following features: • Conceptually significant proportion of building technology in the facade (decentralised) • Glare-free lighting provided with the help of light-deflecting elements that also provide shade • Wooden elements for opening the envelope and regulating individual natural ventilation • Consistent separation of the functions of opening / ventilation (wooden element) and lighting / visual contact (window glazing) A 5.2 Large opening in a sloping roof with glazed sliding elements. When the elements are open, the space gains the quality of an outdoor area. A 5.3 Classification of the functions of building openings. The required regulation or control is central or decentralised. A 5.4 Different cases illustrating strategies for the natural ventilation of buildings

h 5× h

2– 3× h

Wind

Thermal layers

Thermal layers

Thermal layers (+ wind) A 5.4

37

Solution principles for adjustable openings

Cool

Warm

Continuous ventilation

Brief, intense ventilation

a

–

S N

SE/SW E/W

‡

¥

¥

‡

‡

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‡

¥

‡

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–

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¥

¥

¥

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‡

‡

‡

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‡

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–

S N

SE/SW E/W

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¥

‡

‡

‡

‡

‡

¥

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–

S N

SE/SW E/W

¥

‡

‡

‡

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‡

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‡

‡

a

Flat

S

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S

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Outdoor temperature

Protection against break-ins

No sunlight

Screen against views

IV

Views

Mainly direct

Light deflection

III

Anti-glare screen

Mainly diffuse, intense

Sunscreen

II

Solar energy yields

Diffuse, weak

Requirement

Angle of incidence

I

Facade’s exposure

Different case

Sunlight environment

Exterior conditions

¥ Not necessarily required or advisable

‡ Optional

‡ Required

A 5.5

Opening elements should meet the entire range of requirements of the building envelope, with its protective functions, such as thermal insulation, sun screening, sound insulation and protection from both damp and fire, at a reasonable or equivalent standard, even when closed. This applies to planar components and especially to interfaces and joints. Openable elements in the envelope represent – usually in their closed state – a disruption or weak point. The higher the demands on the envelope are, the more costly and complex it is to form the opening so that this kind of conflict does not result in major disadvantages.

The time factor of usage Whether or not certain protective functions (e.g. from driving rain) are still ensured when elements are opened (as a control function), depends on the duration of aperture and options for controlling the opening. Brief opening (e.g. for access or brief ventilation) is less problematic than opening for a long time. Elements that can be opened for cleaning purposes or to let smoke out do not usually require protective functions when they are open. Openings for continuous ventilation in contrast, especially those for cooling at night, require extra protection from the weather (driving rain or wind), break-ins and insects, and, in a noisy environment, additional sound insulation.

Zone

Radiation

Ventilation (thermal)

Lower zone (parapet)

Lighting (through light deflection / diffusion)

Ventilation opening

Lighting Screen against views Screen against sun and glare Views out from inside

Neutral zone

Screen against sun and views (Views out from inside)

Ventilation opening

Middle zone (visual field)

Upper zone (borrowed light)

Optional solar yields

Demands on an opening element

A 5.6

38

Openings used for ingress and egress also require protection from rain and wind. The usual solutions are additional structures such as porches and canopies. Measures to prevent unauthorised entry into a building may also determine the formation of openings. Temporary thermal insulation Compared with closed, highly insulated wall surfaces, translucent opening elements usually represent thermal weak points, even with current technology. Temporary elements (e.g. shutters, roller blinds) can be used at night when exterior temperatures are low to reduce transmission heat loss. The structural elements themselves and the cushions of air they enclose together create this effect. If the element is transparent or translucent, it can also be used during the day. Cleaning and maintenance Transparent glazing in particular requires regular cleaning on both sides. Wooden structural elements require maintenance and the renewal of protective coatings. This means that structural components have to open inwards where cleaning and maintenance is not possible from the outside or where it would be too complex and costly. Meeting this requirement can also offer an opportunity to combine openings with ventilation functions. Performance profiles

All the demands on a building envelope and its openings can be summarised in a performance profile. Since the demands vary greatly with fluctuating daily and seasonal external conditions and are sometimes contradictory, a clear, preferably graphic representation of specific cases can help in the planning process (Fig. A 5.5). Various strategies can be used to implement a performance profile and are outlined below. As well as protective, supply and control functions, further demands arise out of the building’s technical context, such as the structural protection of wood and adaptability to changes in the volume of structural elements resulting

A 5.7

Solution principles for adjustable openings

from differences in temperature, moisture absorption or release and exterior forces (dilatation) or installation aspects.

Integrating openings in the building envelope A planner’s decisions on where, to what extent and in what form openings in the building envelope are reasonable and necessary will depend primarily on access and the building’s ventilation concept. The issue of whether ventilation functions (hygienic comfort) should be combined with those of lighting and views (visual comfort) must be determined because a range of other requirements can result from such combinations. To understand the many possible solutions available it can be advisable to consider the envelope separately (Fig. A 5.8): in and perpendicular to the surface area (Fig. A 5.9). Planning in the envelope (surface area)

Specific planar structural components in the envelope have various functions. Architect Mike Davis’ idea of the “polyvalent wall” envisaged a wall made up of highly specialised layers in the smallest possible space fulfilling all the necessary functions (lighting, ventilation, energy generation etc.) [5]. Usually however, more or less specialised structural components (e.g. ventilation elements, sunscreens etc.) have specific roles in an envelope’s performance profile. It can be worth combining functions to increase efficiency. Adjustable openings with moveable parts are indispensable for natural or mechanical ventilation through a building envelope. The distribution and arrangement of planar structural components and their joints plays a crucial role in planning and detailing, with operability another essential aspect. Planning perpendicular to the envelope (surface area)

Planning elements perpendicular to a building’s envelope involves dealing with the envelope’s structure and individual structural components and determines which specific

functions and related active principles are implemented by means of certain structures such as layers or shells [6]. Not all the structures must be in the envelope; they can also be separated from each other by stationary or rear-ventilated layers of air. Individual elements or the entire structure must be moveable to allow for ventilation. Vertical zoning in multistorey buildings

In multistorey buildings, floor-to-ceiling facade openings can be divided into three different vertical zones per storey in terms of their essential functional aspects (Fig. A 5.6) [7]. The incidence of radiation energy is the same in all zones and directly proportional to the opening surface or glazed area, but the impact of surfaces on a space’s natural lighting increases the further they are from the ground. The parapet area is of secondary importance for incident daylight, while the upper zone is crucial for providing light into the depths of spaces [8]. The light from this zone is usually referred to as “borrowed light”. Efficient shading to prevent rooms from overheating should move up from below, which is not generally the case with typical sunscreen systems. For people sitting and standing, the middle area (also referred to as the field of vision) is of crucial importance for visual contact with the outside. It is also important for lighting and of great relevance as concerns glare. In an environment with multistorey buildings, parapet and borrowed light zones should be taken into account in the context of views and screens. Higher storey users often want glazed parapets to provide visual support in the form of a structural element or printing on panes of glass. Floor-to-ceiling glazing conveys spaciousness in our perception of a space and usually has an advantageous effect on the facade’s impact and design. Temporary thermal insulation (e.g. roller blinds) that reduces heat loss through transmission and radiant heat loss in the cool hours of the night has an equally positive effect in all three areas.

Draught

a

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b

b

c

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A 5.8

A 5.9

Exhaust air

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Pressure

Fresh air

Thermal layer

Effective free / natural ventilation Space depth = max. 3x space height A 5.10

In keeping with temperature layering, openings for incoming or exhaust air should be near the floor or ceiling so as to make use of thermal forces for efficient natural ventilation (if interior air temperature > outside temperature) (Fig. A 5.10). The most important aspects of all three zones can be summarised as follows: 1. Lower zone (parapets): • Of secondary importance for incident daylight • Solar power yields as required • Shade to deflect high levels of solar radiation (before all other zones) • Openings for fresh air 2. Middle zone (field of vision): • Visual contact with the outside • Natural lighting • Individually adjustable anti-glare screens • Shade to deflect high levels of solar radiation 3. Upper zone (borrowed light): • The most important zone for lighting spaces with daylight; ideally light deflection or diffusion into the depths of the space to avoid very steep falls in levels of incident daylight

A 5.5

Table showing a qualitative record of typical exterior conditions as different cases and resulting demands (performance profile) on permeable envelopes in Central Europe. Demands for protection from the sun and glare often conflict with demands for the use of daylight, views and natural ventilation. Continuous ventilation requires that openings be effectively protected against undesired influences from outside. A 5.6 Schematic representation of zoning and classification of functions and their influence on permeability to radiation and air in buildings A 5.7 Pieter Janssens Elinga, Woman reading, 1670, Munich, Alte Pinakothek. The reader wants to protect herself from the gaze of those outside or not be distracted by views. She uses the window’s most effective upper zone to let daylight light the room. A shutter closes the middle zone. A 5.8 Issues in the envelope • Type of surface (even, curved etc.) • Allocation of performance profiles • Fixed or moveable or openable • Opaque, translucent or transparent a A single structure fulfils all functions b Various planar structural components take on different functions c As for “b”, but with moveable structural components A 5.9 Issues with elements perpendicular to the envelope • Implementation of the performance profile • Selection and interaction of structures • Position and order of structures • Modifiability of structures • Moveability of structures a Structures determine the envelope’s permeability and modifiability b As for “a”, but with structures that are not parallel to the envelope c As for “a”, but with some moveable structures or as a structural element that moves as whole A 5.10 Sketch for natural ventilation based on thermal pressure differences (exterior temperature 80

2)

2)

50

1)

No requirements are specified for exterior structural components of rooms in which noise penetrating from outside contributes only slightly to noise levels inside the room due to the activities carried out in the rooms. 2) Here requirements must be identified based on local conditions. a

S(W+F) /SG

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2.0

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2

S(W+F): Total surface area of an exterior structural component of a room [m ] SG: Floor space of a room [m2] b

Sound reduction index for walls /windows [dB] with the following ratios of window surfaces [%]

R'w, res [dB] acc. to Fig. B 1.43 a 10

20

30

40

50

60

30

20/25

30/25

35/25

35/25

50/25

30/30

35

35/30 40/25

35/30

35/32 40/30

40/30

40/32 50/30

45/32

40

40/32 45/30

40/35

45/35

45/35

40/37 60/35

40/37

45

45/37 50/35

45/40 50/37

50/40

50/40

50/42 60/40

60/42

50

55/40

55/42

55/45

55/45

60/45

–

These figures apply to residential buildings with a usual ceiling height of 2.5 m and depth of 4.5 m or more, taking the resulting sound reduction index requirements R'w, res of the exterior structural component in accordance with Fig. B 1.43 b and a correction of -2 dB based on Fig. B 1.43 b into account. c B 1.43

66

on or in existing buildings for the purposes of [...] modifying external components within the meaning of section 9 paragraph 1 line 1 […] must confirm in writing to the client immediately upon conclusion of the work that the construction or system parts modified or installed by him meet the requirements of this regulation (contractor declaration).” Failure to issue, improper issue or failure to issue such a confirmation for an existing building in good time is an offence under section 27 (3) and can result in the imposition of a fine.

Sound insulation Sound is an important external parameter in buildings (soundproofing against exterior noise) and essential for interiors (soundproofing in buildings, the acoustics of rooms) since sound can come from both sides of the building envelope. The issue is on the one hand noise immission: noise from outside, from road traffic and other sources, the specific emission spectrum of which must be taken into account in planning. On the other hand, sound emission must also be considered: i.e. sound moving from one space into another and in some cases also to the outside (e.g. from commercial or industrial uses that make noise). Rooms must have specific acoustic properties, taking issues such as noise levels, the intelligibility of speech or other characteristics, such as use of a room for music, into account. Sound insulation involves measures to reduce the undesirable transmission of sound from a source to users, where the source of the sound and the user are in separate spaces. If both are in the same space, the main focus should be put on surface sound absorption. A distinction is made between airborne and structure-borne sound insulation. Sound waves spread out from their source into a space almost spherically through the medium of air (airborne sound). When mechanical influences excite a solid material (e.g. steps on a floor), sound waves spread in the material of structural elements (structure-borne sound), exciting the layer of air on the other side and adjoining areas when they come into direct contact with them. From there they are transported further as airborne sound. Sound waves can travel a very long way through structures. If a building’s solid elements are directly structurally coupled, i.e. rigidly connected, as an installation wall may be with a ceiling or adjoining walls, sound can be transmitted for long distances through the elements and connections. This phenomenon is referred to as structure-borne sound transmission, or when it involves adjoining structural elements, as flanking or vertical sound transmission. Structure-borne sound insulation makes stringent demands on planners and requires careful construction because sound can be transmitted almost unrestrictedly, through very small

Sound insulation class

Estimated sound reduction index R'w of functioning window integrated into the building, measured in accordance with

Required estimated sound reduction index Rw of an integrated functioning window [dB] tested in accordance with DIN 52 210 Part 2

1

25 to 29

≥ 27

2

30 to 34

≥ 32

3

35 to 39

≥ 37

4

40 to 44

≥ 42

5

45 to 49

≥ 47

6

≥ 50

≥ 52

Estimated sound reduction index RW [dB]

Requirements and protective functions – building physics fundamentals

60

Air gap dL [mm] 80 60 40

50

Double pane

24 12

40 Comparison: single pane 30

20 5 B 1.44

points of contact (‘sound bridges’) [12]. The solution is acoustic decoupling, i.e. creating “soft” connections between all relevant structural components (e.g. floor coverings and slabs or sanitary installations and walls), so that oscillations are not directly transmitted through them. One strategy for reducing direct and flanking airborne sound transmission is to increase the mass of the structural components participating in the transmission, i.e. make structural components as heavy and inert as possible. Structural components made of a material that is as dense as possible and sufficiently thick are not very susceptible to excitation by airborne sound waves. Another effective measure against airborne sound transmission is the most effectual possible sealing of all joints, gaps and cracks. A double-layered structure without rigid connections and with an insulated space between the layers can also reduce airborne sound transmission (mass-spring-mass principle) [13]. Double-layered systems have, however, a specific resonant frequency which impairs sound insulation, so this resonant frequency should be as deep as possible. Such systems are especially effective if the two layers have a different mass and differing coincidental cut-off frequencies. Opening elements are almost always sound insulation weak points because they use various materials and have construction joints and usually a lower mass per unit area than surrounding exterior wall components, which results in less sound insulation. Sound insulation requirements apply generally to the entire exterior structure on completion. As well as windows, this includes structures such as roller shutter casings, vents and exterior walls with structural joints. The required sound insulation is identified as the sound reduction index (R'w, res) resulting for all individual structural components in total. DIN 4109 on “Sound insulation in buildings” and the VDI guideline 2719 on “Sound insulation of windows and their auxiliary equipment” are the relevant standards for the sound insulation of building envelopes. The VDI

guideline defines six sound insulation classes with specifications ranging from 25 dB for single-pane windows to up to over 50 dB for casement windows with separate frames and special sealing and glazing (Fig. B 1.44) [14]. Planning the sound insulation of exterior structural components (and openings in them) proceeds room by room, with the required sound insulation determined and then designed for the entire exterior component. The (exterior) sound level to be reduced, depending on planned usage, and admissible interior sound levels must be taken into account. Once the necessary total sound insulation has been calculated, the requirements for individual components (such as windows) are determined based on the relative proportions of their surface areas. DIN 4109 prescribes a method that is shown as an example here. The standard divides minimum airborne sound insulation requirements for exterior wall structures into seven noise levels with applicable exterior noise levels (Fig. B 1.43). The required resulting sound reduction index (R'w, res) of an exterior component (exterior wall, windows and other structures) must be demonstrated. The resistance of a wall, ceiling, or window to the passage of airborne sound is measured by means of the sound reduction index R and sound level difference D (difference between the two areas, inside and out) for a defined frequency range and is specified in decibels [dB]. The weighted sound reduction index is assessed based on a frequency range of 100 to 3,150 Hz (50 – 5,000 Hz with requirements on the acoustics in the room, reverberation time and damping, for example). ‘Weighted’ here means that the sound reduction index figures are compared with a set reference curve (DIN EN ISO 717-1) which shows the typical process in a solid structural component. The emissions spectrum can be modified depending on expected external conditions. Indices C and Ctr are used to describe the type of outside noise and serve as correction values to approximate a match between the individual sound insulation values measured [15] and the subjectively perceived noise reduction:

6

8

40 20 10 15 30 Total thickness of the glass dGI [mm] B 1.45

C pink noise (A-weighted) Ctr standardised urban traffic noise (A-weighted) Sealing and sound insulation of joints

As the resulting sound reduction index depends on sufficient sealing and sound insulation of joints, DIN 4109 and VDI guideline 2719 contain general requirements for these. • “Joints between window frames and exterior walls must have state-of-the-art sealing.” (connecting construction joints) [16] • The sound insulation of windows is “significantly influenced by the impermeability of joints [...]. It decreases with greater joint widths and lengths” [17], so these should be kept to a minimum. DIN EN 12 354-3 offers a complementary method for planning individual structural components, including connecting construction joints. Once the resulting required sound reduction index of a building envelope (R'w, res) is known, the sound insulation for individual structural components and connecting construction joints can be planned. The sound insulation required for each structural component can be calculated based on frequency or individual specifications. The ability of filling materials and/or sealing systems to insulate joints against sound can be verified (in accordance with DIN EN ISO 10 140-1) by laboratory testing (Fig. B 1.46).

B 1.43

B 1.44 B 1.45

Tables pursuant to DIN 4109 a Airborne sound insulation requirements on structural elements b Correction value for the resulting sound reduction index required in accordance with Fig. B 1.43 a depending on the proportion of S(W+F) to SG c Sound reduction index (R'w, res) required for combinations of exterior walls and windows Sound insulation classes of windows in accordance with VDI guideline 2719 Estimated sound reduction index RW of double panes as a function of glass thickness and distance between the panes using air as filling

67

Requirements and protective functions – building physics fundamentals

Resulting sound reduction index Rw,res [dB]

Joint noise insulation Rs,w

1 dB rule

35 dB

45 dB

50 dB

50 45 40 35

Application to a large window medium-sized window small window

30

25 20 25

30

35

Type of joint

40

45 50 Noise insulation Rw of the window [dB] B 1.46

Joint noise insulation RST, w [dB] for joint widths of 10 mm 20 mm 30 mm

Empty joint

15

10

5

35..45

30..40

25..35

PU installation foam

≥ 50

≥ 47

≥ 45

Compressed sealing tape, compression level ≤ 50 %, one-sided

≥ 30

–

–

Compressed sealing tape, compression level ≤ 20 %, one-sided

≥ 40

–

–

Compressed sealing tape, compression level ≤ 20 %, double-sided

≥ 50

–

–

Multi-functional tape (compressed sealing tape over the entire frame depth), compression level ≤ 35 %

≥ 40

≥ 35

–

Joint sealed on both sides with joint filler cord and elastic sealant

≥ 55

≥ 54

≥ 53

One-sided connection joint foil ≥ 1 mm

≥ 40

≥ 35

≥ 30

Double-sided connection joint foil ≥ 1 mm

≥ 50

≥ 45

≥ 40

Stuffed with mineral fibre (depending on stuffing quantity)

B 1.47

Monolithic wall

Solid wall with composite thermal insulation system

Double wall with rear ventilation and core insulation

Exterior insulation with a light facade

Double wall, core insulated (prefabricated component)

Use of casing frame or rubble fill B 1.48

68

Structural component connections It is advisable to combine various joint materials to optimise the sound insulation of joints as this will improve their sound insulation. The figures shown in Fig. B 1.47 refer to the exterior wall and installation configurations outlined in green in Fig. B 1.48. The joint configurations outlined in red impair sound insulation, so the figures provided for these installation situations do not necessarily apply. The sound reduction index is much lower when there is an effective sound insulating connection between inside and out through the insulation layer. This must be particularly taken into account where a high level of sound reduction is required. If necessary, stable, insulated casing structures (outlined in orange) can impede secondary sound paths in such cases (depending on materials and structures used). Joints Joints must be planned and built so as to retain a structural component’s sound reduction index Rw. The sound pressure on edges is 4 times as high and in corners 16 times as high as the sound pressure in the middle of an element, so sound insulation here will depend heavily on the quality of joints. Small holes or hairline cracks in joint areas can significantly impair overall insulation by more than 10 dB (Fig. B 1.49). An airtight joint is a fundamental prerequisite for effective thermal insulation, protection from damp and sound insulation, so these joint seals must be circumferential, softly yielding, elastic in the long term, age-resistant and easy to exchange. Such construction that fulfils high noise insulation requirements results, however, in a rebate that is so airtight that a minimum air exchange rate is no longer ensured when the windows are closed (see “Minimum air exchange”, p. 61f.). In such cases, it is possible to install a “sound absorbing ventilation window” which mechanically draws in outside air (with a ventilator) through a sound absorbing channel under, next to or above the window. If the channel is under a window, incoming air can also be directly heated by installing a heating element under the window (see “Active solar energy use”, p. 190ff.). The following measures can positively minimise the negative effects of noise permeating joints: • Sealing materials, strips and tapes can also improve the acoustic insulation properties of joints. • Installing sealing on both sides (inside and out) greatly increases the acoustic insulation properties of joints compared with sealing on one side only (only on the inside, outside only structural protection). Sealing foils have a lower mass, so their effect cannot be equated with that of the sealing systems listed above. • Joint insulation that uses PU foam, spray cork or mineral fibres in sealing systems,

such as sealant joints or precompressed sealing tape, contributes to thermal and sound insulation measures. Filler materials should fill the joint as fully as possible. • Staggering joints (e.g. in openings in walls) to deflect sound waves. As well as the number and formation of joints, the following factors are important elements in noise insulation for windows: • Type of window (single-pane, composite or casement window) • Frame material • Pane structure (single, multiple) the distance between the panes influences the spring effect (mass-spring-mass principle; Fig. B 1.45, p. 67) • Glass thickness (mass, asymmetrical structure) • Glass type (float or laminated glass coated with casting resin or special PVB foils, see “Glass as a filling material”, p. 86f.) • Gas filling in the space between the panes (potential improvement of approx. 1 dB) • Type of fittings, number of latches (to improve imperviousness to wind loads) • Type of structure and connections (Fig. B 1.48) Sound reduction in joints The sound reduction index RST, w of construction joints influences the overall sound reduction index of an external structural component R'w, res, so the sound reduction index of joints should always be as high as possible. Effective planning requires detailed knowledge of the whole joint and its individual elements (Fig. B 1.47). Depending on the requirement on the weighted sound reduction index Rw, R of a window, the joint sound reduction index RST, w must be designed so as not to reduce overall sound insulation. A window’s unfavourable proportion of area to the length of the joint results in a calculated higher required sound reduction index for joints. The following serves as a guide in determining the resulting required sound reduction: RST, w ≥ Rw, R + 10 dB If this proportion is used, the joint will not normally decrease the sound reduction index Rw, R of a window (with the sound reduction index for the joint RST, w) by any more than 1 dB. Soundproof windows

Soundproof windows generally make use of several optimisation measures in combination (Fig. B 1.50) but usually have special insulating glazing with an asymmetric structure of panes of different thicknesses and different natural resonant frequencies inside and out (see “Sound-insulating glazing”, p. 93). For sound insulation purposes it

does not matter which pane is outside, but for reasons to do with load-bearing (especially wind load, see “Horizontal wind loads”, p. 76), the thicker pane is usually installed outside. Double glazing has sound insulation values comparable to those of triple glazing (Rw up to 50 dB), although the latter is thicker and heavier. Studies carried out at ift Rosenheim and HFT Stuttgart have shown that the middle pane has practically no influence on sound insulation values [18]. Summary remarks

The fundamental principle of statutory building regulations and DIN 4109 is that the required sound insulation values shown above apply to completed, installed structural components, including joints. The following factors determine the sound insulation in and around openings: type of window and opening, type of glass and space between the panes, structure and quantity of sealing, frame construction and material, joints in structural components (material, construction etc.), pane size and format, and any other elements integrated into openings such as rolling shutters and their casings etc. (Fig. B 1.51). It is essential that joints (sealing) be impervious. Insulating materials can enhance the sound insulation of joints because some, such as mineral wool, have thermal insulating as well as sound-absorbing properties. The unfavourable proportion of a structural component’s surface area compared with the area of joints means that a much higher sound reduction index must be calculated for joints (≥ 10 dB) than the sound insulation required for an individual structural component so as to prevent the component’s sound insulation from deteriorating once the component is installed. High sound insulation requirements require careful construction of joints because the smallest leak can impair sound insulation by up to 10 dB. Sound insulation issues should be considered from the outset of early design planning by • Identifying all requirements (standards, building regulations and other generally accepted technical rules and standards) and taking economic aspects into consideration. A general stipulation in a tender, such as “sound and thermal insulation in compliance with DIN”, is not enough. • Designing an appropriate floor plan (position of sources of noise in relation to spaces requiring protection) • Positioning and constructing openings, and • Planning separating and flanking structural elements (vertical sound transfer has a major influence on achievable sound insulation).

Sound reduction index R [dB]

Requirements and protective functions – building physics fundamentals

60

50

40

30

20

10 125

250

500

1,000 2,000 Frequency f [Hz] Rw, p

Window installed acc. to test standard Empty joint, window – wall Circumferential hair joint (foam – wall) Lewis hole in foam Joint, window – wall fully packed with foam, foam adheres to fusion faces Weighting curve

45 dB 12 dB 32 dB 33 dB

43 dB B 1.49

B 1.46

B 1.47

B 1.48

B 1.49

B 1.50

Calculated influence of joint noise insulation for a structural connecting joint on the resulting sound reduction index of an installed window. Example of measurements: If the joint noise insulation is RS, w = 35 dB (red curve), the sound reduction index of a window is reduced by Rw = 35 dB (purple in the example) and by around 6 dB for average window sizes (red arrow). If joint noise insulation is RS, w = 45 dB (blue curve), the reduction for the same window will be 1 dB (blue arrow). Joint noise insulation for structural connecting joints of windows, joint depth 50 –100 mm (these figures will also be included in DIN 4109 in future) Positive (outlined in green) and negative (outlined in red) influence of exterior wall and installation situation on sound insulation, normal window structures and casing structures (outlined in orange) Tested sound reduction index Rw, P of a window depending on different joint formations and flaws between the window and wall Cross section of an aluminium sound-insulating window

Good-quality workmanship and construction supervision can also make a major contribution to effective sound insulation. B 1.50

69

Requirements and protective functions – building physics fundamentals

Rw

Window type

Rebate sealing

Dimensions / requirements

25 dB

Single window

–

dtot ≥ 6 mm space between the panes ≥ 8 mm RW, g ≥ 27 dB

25 dB

Composite window

–

dtot ≥ 6 mm space between the panes, discretionary

30 dB

Single window

1

dtot ≥ 6 mm space between the panes ≥ 12 mm RW, g ≥ 30 dB

30 dB

Composite window

1

dtot ≥ 6 mm space between the panes ≥ 12 mm RW, g ≥ 30 dB

30 dB

Casement window

–

–

35 dB

Single window

1

dtot ≥ 10 mm space between the panes ≥ 16 mm RW, g ≥ 35 dB

35 dB

Composite window

1

dtot ≥ 8 mm or ≥ 6 + 4 /12 /4 space between the panes ≥ 40 mm

35 dB

Casement window

1

–

40 dB

Single window

2

RW, g ≥ 42 dB

40 dB

Composite window

2

dtot ≥ 14 mm or ≥ 8 + 6 /12 /4 space between the panes ≥ 50 mm

40 dB

Casement window

2

dtot ≥ 8 mm or ≥ 6 + 4 /12 /4 space between the panes ≥ 100 mm

45 dB

Casement window

2

dtot ≥ 12 mm or ≥ 8 + 6 /12 /4 space between the panes ≥ 100 mm

B 1.51

Fire protection Building openings are of central importance in fire protection. They “break up” the fabric of exterior and separating walls (between fire zones), creating, in this sense, special or weak points in fire protection. Depending on their structure, they can even become a source of danger from falling parts in the event of fire. At the same time, they can also serve to extract heat and exhaust gas and function as air intake points for smoke and heat extractors and as possible escape routes and emergency exits. Fire protection is designed to prevent or impede fires and the spread of smoke and

70

flames while maintaining a structure’s loadbearing capacity for a specific period so that people and animals can be rescued, the fire effectively fought and the property saved. This is why most countries have many statutory and technical regulations and guidelines at various levels. In Germany, the federal state building regulations (planning control laws) define the main safety objectives, while guidelines issued by TÜV, DIN, VDI and VDE etc. deal with the choice of building materials and their behaviour in fire in the context of different types of structures and protective measures. Appendix 1 of the Construction Products

Regulation (EU Regulation No. 305/2011), in force across Europe since July 2013, also deals with fire protection as a fundamental requirement for buildings (see “Construction Products Regulation”, p. 83f.). Fire behaviour and building materials classes

The possibility of fire is relevant in all construction, although fire itself is usually less dangerous than its consequences (including unforeseen behaviour of people affected). Most fatalities in fires are caused not by burns but by smoke. Building materials have a range of various behaviours in fire, i.e., when they ignite, how well they burn, what thermal load they release, the extent to which they produce smoke and what their smoke is composed of. Building products are tested for performance, ageing capacity, sustainability, and safety as well as behaviour in case of fire. The European DIN EN 13 501-1 standard (in Germany the “old” DIN 4102 applies also) defines the flammability of building materials and prescribes consistent testing methods in classes A – F. German building law classifies products as not flammable, flame-resistant, normally flammable and easily flammable, depending on the proportion of flammable material in them. The Building Rules List (Bauregelliste) correlates these with the “old” DIN classes A1, A2, B1 to B3 and European regulation classes A to F. The classifications used in the European regulation also include subclasses for smoke emission (s1 – s3) and flaming droplets (d0 – d2). Details on these are provided on CE labels or in the declaration of performance for a structural component, e.g. C-s1 – d2 (Fig. B 1.52). Section 17 Paragraph 2 of the Model Building Regulation (Musterbauordnung – MBO) states that easily flammable materials (building material class B3 or F) can be used if they are no longer easily flammable in their installed condition (e.g. as a composite material). Fire tests are used to verify the classification of a building material or building product in a building materials class [19]. Although basic materials are important to a component’s behaviour in fire, the subsequent semi-finished or construction product, with all its layers and treatments, is much more crucial. A structural component’s form and structure are also important and can greatly impact its behaviour in fire by producing a stack effect in hollow spaces, for example. Planners should not rely on general statements on the fire protection classification of a specific building material but should seek out more detailed information and ensure that the products they plan to use are verified for use in each case. Federal state building regulations (Landesbauordnungen – LBO) require all construction materials, including materials used for building joints and connections, to be normally flammable at most, a requirement which can be met by using building materials in at least class E or B2.

Requirements and protective functions – building physics fundamentals

Fire resistance classes

DIN EN 13 501-2 classifies structural components (elements and structures) in fire resistance classes according to their behaviour in fire (Fig. B 1.53). It groups building openings into the following situations: • Load-bearing structural elements with or without a room-enclosing function (with or without glazing), e.g. exterior walls, roofs, loggias, access balconies etc. • Non-load-bearing structural elements (with or without glazing), e.g. curtain facades and other non-load-bearing exterior walls, fireresistant doors and closures and all closing mechanisms, smoke protection doors, joints in structural components etc. • Products and systems for protecting structural components, e.g. fire protection coatings, cladding and screens. Germany’s individual state building regulations (Landesbauordnungen) prescribe fire protection requirements for building materials, including materials used for closures and for individual structural components (fire-retardant, highly fire-retardant, fire-resistant) depending on a building’s class. The fire resistance classes of individual structural components as defined in DIN 13 501-2 are incorporated into the building approvals terms of the state building regulations. DIN EN 13 501-2 classifies the fire resistance behaviour of structural components according to the following performance criteria: loadbearing resistance (R), enclosure (E) and thermal insulation (I). These may also be complemented by additional requirements such as permeability to radiation (W), mechanical stability (M), self-closing (C) and smokeproofing (S). The criteria are represented by their corresponding capital letters. Fire resistance classes measure the duration of a component’s resistance to fire in minutes, i.e. the minimum length of time a structural element must meet the performance requirements indicated by its capital letter, e.g. 30, 60, 90, 120 or 180 minutes (classification period). The European system uses more precise units of 15, 20, 30, 45, 60, 90, 120, 180 and 240 minutes (Fig. B 1.55) [20]. Doors and portals in DIN 4102 classes T 30 and T 60 are classified by the European system as EI260-C5-Sa (doors) or EI230-C2-S200 (portals). DIN 4102 RS also classifies self-closing smoke protection doors as C5-S200 [21].

Building regulation designation

Not flammable

Low flammability

A1

‡

A2

s 1, d 0

‡

B, C

s 1, d 0

‡

B, C

s 3, d 0

B, C

s 1, d 2

‡

Normal flammability Easily flammable

B, C

s 3, d 2

D

s 3, d 0

D

s 3, d 2

E

d2

F

DIN 4102-1 class A1 A2

B 11)

B 21) B3

Details on high smoke emissions and burning droplets/drips in the certification for use and labelling B 1.52

Fire resistance class in DIN 41021)

Building regulation designation

Fire resistance duration in an ISO standard fire

F 30 – B

Fire-retardant

≥ 30 min

F 30 – A

Fire-retardant, made of non-combustible materials

≥ 30 min

F 60 – AB 2)

Highly fire-retardant

≥ 60 min

F 60 – A

Highly fire-retardant, made of non-combustible materials

≥ 60 min

F 90 – AB

Fire-resistant

≥ 90 min

F 90 – A

Fire-resistant, made of non-combustible materials

≥ 90 min

(F120)

(Highly fire-resistant)

(≥ 120 min)

(F180)

(Very highly fire-resistant)

(≥ 180 min)

Firewall

–

Fire resistance class acc. to DIN EN 13 501-2 for structural elements With No spatial enclosure spatial enclosure Loadbearing

Not loadbearing

Loadbearing

REI 30

EI 30

R 30

REI 60

EI 60

R 60

REI 90

EI 90

R 90

REI – M 90

EI – M 90

1)

acc. to DIN 4102-2 for walls, columns, ceilings, beams and stairs 2) AB: main parts made of non-combustible materials

Derivation of the representative letter

Criterion

R (Resistance)

Load-bearing capacity

E (Integrity)

Spatial enclosure

B 1.53

Application

I (Insulation)

Thermal insulation (in case of fire)

W (Radiation)

Limit the permeation of radiation

M (Mechanical)

Mechanical impact on walls

S (Smoke)

Restrict permeation of smoke (impermeability, leak rate)

Smoke protection doors (as additional requirement also for fire protection barriers), ventilation systems incl. flaps

C ... (Closing)

Closing properties (possibly with number of load cycles)

Smoke protection doors, fire protection barriers (incl. closures for conveyor systems)

P

Maintenance of energy supply and /or signal transmission

Electrical cable systems generally

I1, I2

Various thermal insulation criteria

Fire protection barriers (incl. closures for conveyor systems)

f (full)

Load imposed by a “full” standard time temperature curve (fully developed fire)

Double floors

... 200, 300, ... (°C)

Temperature load specifications

Smoke protection doors

i∫o i o i o (in – out)

Direction of classified fire resistance duration

Non-load-bearing exterior walls, installation shafts/channels, ventilation systems /flaps

a∫b a b a b (above – below)

Direction of classified fire resistance duration

Suspended ceilings

ve, ho (vertical, horizontal)

Classified for vertical / horizontal installation

Ventilation pipes / flaps

∫

Typical sound reduction index depending on glazing and type of window structure (dtot = total glass thickness; Rw, g = laboratory test values for a standard format pane 1.23 ≈ 1.48 m) B 1.52 Classifications of building materials per DIN EN 13 501-1 and DIN 4102-1 B 1.53 Fire resistance classes of structural components in DIN EN 13 501-2 and their classification in building regulation designations (classification in DIN 4102) B 1.54 Fire resistance classification as defined in DIN EN 13 501-1 and DIN EN 13 501-3

‡

‡

‡

1)

European class acc. to DIN EN 13 501-1

‡

‡

∫

B 1.51

Additional requirements No smoke No flammable drips /droplets

To describe fire resistance

Additional specifications for classifying the fire behaviour of construction materials acc. to DIN EN 13 501-1 s (smoke)

Smoke emission

Smoke emission restriction requirements

d (droplets)

Burning droplets /drips

Requirements involving burning droplets /drips

... fl

Fire behaviour classes for floor coverings B 1.54

71

Requirements and protective functions – building physics fundamentals

The suitability of building materials or structural components for providing preventive fire protection in buildings is usually verified by a national technical approval (“allgemeine bauaufsichtliche Zulassung” – abZ), via a national general test certificate (“allgemeines bauaufsichtliches Prüfzeugnis” – abP) from a recognised testing authority, by specific approvals in individual cases or via CE labelling (in accordance with product standards, with or without certification, or compliance with a Technical Building Rule). Unlike the German state building regulations (Landesbauordnungen), testing and classification standards such as DIN EN 13 501 do not specify building regulation requirements (fire-retardant, highly fire-retardant, fireresistant). The suitability of building materials or structural components listed in DIN 4102-2 and DIN 4102-4 does not have to be separately verified. At the European level, the CWFT (“Classified without Further Testing”) list classifies the behaviour of building materials in case of fire. Structural components whose suitability cannot be assessed by DIN EN 13 501-1 and 2 (or in Germany in DIN 4102-4) must be individually verified by a national technical approval issued by the German Institute for Structural Engineering (Institut für Bautechnik – DIBt) in Berlin (Fig. B 3.58, p. 140).

Separating wall E

EW

EI

20

E-20

EW-20

EI-20

30

E-30

EW-30

EI-30

60

E-60

EW-60

EI-60

90

E-90

EI-90

120

E-120

EI-120

Fire resistance duration in minutes 15

EI-15

45

EI-45

180

EI-180

240

EI-240

E

EW

EI1

EI2

15

E-15

EI1-15

EI2-15

20

E-20

EW-20

EI1-20

EI2-20

30

E-30

EW-30

EI1-30

EI2-30

45

E-45

EI1-45

EI2-45

60

E-60

EW-60

EI1-60

EI2-60

90

E-90

EI1-90

EI2-90

120

E-120

EI1-120

EI2-120

180

E-180

EI1-180

EI2-180

240

E-240

EI1-240

EI2-240 B 1.55

72

DIN EN 13 501-2 defines fire-resistant glazing as a glazing system consisting of one or more transparent or translucent panes of glass installed in a suitable manner (e.g. with frames, sealing and fasteners) that can meet the fire resistance duration criteria required where it is installed. Fire-resistant glazing – including F and G glazing as defined in DIN 4102-13 (classes E or EI in DIN EN 13 501-2) as a solution for building openings with particular fire safety requirements – can thus only be installed as special glazing in specific, approved and type-tested frame systems. In Germany, they always require a national technical approval or European technical assessment under ETAG 003 (Guideline for European technical approval for internal partition kits for use as non-load-bearing walls). Since fire-resistant glazing is regarded as part of the wall or ceiling in which it is installed, it is not a separate, fire-resistant structural component, but is classified with structural components in the installation location (class EI, EW or E in DIN EN 13 501-2). Fire-resistant glazed partition systems (F and G glazing) usually resist flames and hot gases for a defined period. F glazing is heat insulating, but G glazing barely restricts the permeation of radiated heat and presents a risk of spontaneous ignition on the side furthest from the fire (see “Fire-resistant glazing”, p. 116ff.). F glazing is suitable for building openings with special fire protection requirements, e.g. preventing fire spreading to the facade, when buildings are diagonally adjoining (5-metre corner region) and for pedestrian walkways or glazed exterior areas of escape and emergency routes. As well as fire-resistant glazing, other options can be considered for fire protection closures of building openings such as special doors (rolling, lifting, fold-and-lift, sectional and sliding doors with the appropriate approval) and curtains [22]. In practice, however, fire safety requirements often mean that such glazing is dispensed with for reasons of cost. Proof of suitability and official approval

Fire protection barriers Fire resistance duration in minutes

Fire-resistant glazing

In Germany, a national general test certificate (abP) from an authorised testing centre or national technical approval from the DIBt is regarded as proof of suitability for structural components not listed in a standard as fireresistant structural components. This means that building supervisory authorities are no longer obliged to test the suitability of the component for the intended purpose. Installation of such approved fire protection elements is then regulated by a certificate of serviceability (approval, national general test certificate (abP), national technical approval (abZ) etc.), which also includes structural connections in the type, construction and position of fastening elements and joining materials.

Specific approvals can be applied for in individual cases if no products approved by building supervisory authorities (e.g. fire protection glazing) are available for fulfilling a specific requirement or if construction will diverge from approved methods. A specific individual case approval then replaces a building authority approval as an exception. The client must apply for specific approvals in individual cases through the relevant building supervisory authorities from the highest building regulatory authority of the federal state in which the project is being built. Whether a material or product can be used in a certain area in a building, e.g. closure of a large skylight, depends on its fire protection classification and on other, partly crucial factors and properties such as: • Melting point and ignition temperatures • Whether the material or product drips as it burns, because hot drips can be very problematic • Whether the material retracts in fire, creating openings to the outside for heat, smoke and gases (similar to an automatic heat and smoke vent), • Whether a material shrinks in fire, opening up undesirable openings for smoke and flame in the frame that allow fire to spread • Which (toxic) combustion products are produced • Whether a material is installed in the open or is concealed (no visual inspection possible) • The extent to which and at which temperatures structural function is lost and what the results of this will be. Structural conditions, e.g. areas into which toxic smoke and gases produced by fire can permeate, which temperatures in an occupied interior are required for fire to reach an area (distance from fire load) and how the situation for rescuing people is assessed (fire scenario), must also be taken into account in choosing materials and products. Other aspects of a building that can be used to enhance fire protection include restricting user numbers (by regulating visitor flows), increasing and improving escape options or adapting the building’s technology (with controlled incoming and outgoing air, fire alarms and sprinkler systems). These aspects, which can involve considerable additional cost, are not dealt with in a national technical approval. Decisions regarding material selection and the type of construction should therefore be made as early as possible and by an interdisciplinary team including building approval authorities and fire safety specialists.

B 1.55

Glazing for “E-Integrity” fire protection class, classes as defined in EN 13 501-2, tested in accordance with EN 1364-1

Requirements and protective functions – building physics fundamentals

Electromagnetic damping Electromagnetic damping provides protection against undesired but ubiquitous electromagnetic waves, so-called electrosmog. Practically all electrical devices and equipment used in private and in industry emit this kind of radiation (source of interference). Protective measures against radiation emissions can be taken either directly at the source or by screening entire spaces and buildings. Conversely, the screening or damping of disruptive electromagnetic radiation from outside is sometimes required, e.g. protection against undesired mobile phone radiation. Electromagnetic damping is particularly essential in and around airports, especially radar reflection damping (damping of primary and secondary radar signals that reflect off building facades). Electromagnetic waves can be technically damped in various ways, ranging fromscreening individual structural elements up to whole rooms. Windows effectively contribute to screening in the latter case. Screening rooms reduces disturbance from radiation (electrical and magnetic fields and electromagnetic waves) to a specific level. The frequency range goes from kHz into the GHz range, with the damping value depending on individual usage. Uncoated glass is very permeable to electromagnetic waves in the right frequency range, i.e. it is not very absorbent or reflective. Damping can be improved by applying low-e coatings, which increase reflection. The lower the coating’s electric resistance, the more it damps radiation. A prescribed shielding attenuation value can be achieved in individual cases by installing the glass in a special way, although all the panes of glass and window frames must have flawless equipotential bonding (Faraday cage). The radar reflection damping required near airports usually ranges from 10 to 20 dB, which reduces reflected signals by 90 – 99 %. Among the important factors for damping are the size of the building, the facade’s angle and the distance from and position relevant to the radar unit (angle dependence). These requirements can be met for transparent structural components by special glass installations that produce a phase-shifted overlapping of incident and reflected radar waves and reduce reflection. Planners and manufacturers should work together to identify a suitable glass installation in each case depending on the radar damping, thermal insulation and sun and noise protection etc. required.

vertical live loads • Horizontal loads: horizontal live loads, wind suction and pressure • Changes in length and deformations due to fluctuations in temperature and air pressure • Loads from the building: settling, ground motion • (Improper) usage • Mechanical onslaughts (e.g. burglary) • Loads arising from other usage aspects • Installation location • The opening’s position in the building envelope

(p ∙ V)/T = constant Thickness of glass panes

Glazing is designed to divert surface loads into a suitable substructure, so its load-bearing capacity must be ensured through the thickness of the panes, taking the bending stress of the type of glass into account. The most adverse load conditions from dead weight, live loads (especially horizontal loads such as contact and impact loads), plus wind and snow loads (in keeping with DIN 1055-4) are always used in measuring load-bearing capacity. DIN 1055-4 prescribes that deflection calculated after loading must be under 1/200 over the length of the pane. Deflection along the longest edge of a pane is generally limited to a maximum of 15 mm to ensure that the glass edge seal function is not impaired. Determining the thickness of glass required is complex and is now usually done by computer and, since 2011, in accordance with DIN 18 008-2. The following parameters are among those included in the calculation: • Type of glass • Size of panes • Installation site (height, wind zone, building’s dimensions, terrain category, snow load zone) Planning glazing in accordance with DIN 18 008-2 usually results in thicker glass than that prescribed in now obsolescent diagram values such as glazing industry guidelines or the old standard, although these can still be used to make general estimates [23]. In planning insulating glazing, it is usually assumed that the exterior pane has to absorb the entire wind load (pressure and suction) and exterior live loads. It is also assumed that there is no compound effect through the space between the panes, so inner panes can be thinner and designed to deal with half the wind load, as long as they do not have to bear any further loads from the inside. In addition to the dimensions panes need to have to bear specific loads, further factors such as installation, construction, usage and climate loads may mean that thicker panes are required.

Mechanical requirements Particular loads on insulating glazing

Mechanical requirements on building openings result from a range of loads and demands and are defined in various laws, standards and technical regulations: • Vertical loads: the structure’s own weight,

loads) in this area. When the temperature rises, the pressure of the gas in the space between panes also increases and pushes the panes and spacers outwards. If outside air pressure rises due to weather, the relative pressure in the space between panes changes, drawing the panes and spacers inwards. Depending on the bending stiffness of individual panes, deformation can occur or pressure be put on the glass and edge seal. This gas equation explains the physical phenomenon.

Insulating windows always contain the same amount of gas in the space between panes, so as well as wind loads, there are other mechanical loads on panes due to changes in temperature and air pressure (climate

p V T

Pressure [Pa or N/m2] Volume [m3] Temperature [K]

If one of these parameters changes, it must be compensated for elsewhere. The larger the enclosed volume, the greater the effect. Fig. B 1.56 also shows that in a worst-case scenario these two effects can interact, increasing deformation, which must be taken into account in planning panes. These factors may require a specification of installation height when insulating glass units are ordered because their height determines their filling’s pressure (as a neutral position). These physical conditions, referred to as “climate loads”, have been known for a long time but growing use of triple glazing with increasingly large spaces between panes is progressively exacerbating the problem. Structures quickly reach their limits when wind and climate loads interact (Fig. B 1.57). Very short (= rigid) edge lengths or unfavourable edge length proportions can increase the risk of panes breaking and shorten a unit’s service life. These kinds of pane deformations show on the outside as distortions, especially in reflection. The use of coated and /or coloured panes in sun-protective insulating glass can cause panes to heat up in summer due to absorption and amplify the effect described, so the space between the panes of sun-protective insulating glass should be no more than 12 mm. Partly shaded situations make particular demands on the resistance of individual panes to changes in temperature. Depending on the size and format of the panes, type of glass and installation situation, it may be advisable to use prestressed glass (toughened safety glass) or partly prestressed tempered glass in some cases. Maximum size of frames and sashes

Various mechanical requirements restrict the maximum size of glazing and window elements as a whole, especially individual sashes, although there is no generally applicable minimum or maximum size. These will depend on the following aspects: • Frame profile material, frame structure and dimensions (manufacturer-specific) • Type of opening

73

Requirements and protective functions – building physics fundamentals

• Choice of fittings for closing and moving sashes • Situation on the building site (accessibility, availability of lifting equipment etc.) • Planned use of the building (Older people may not be able to move very large sashes, while robust elements with small sash formats may be expedient for schools.)

not subject to bending loads because forces emanating from the sash are completely transferred through the structural component joint into the building. Consequently, the sash frame does not have to be dimensioned to resist bending. The installation situation on the building site can be as important to a unit’s size and design as the type of installation and the element to be built into the opening. Additional measures may be required here (e.g. temporary reinforcement for transport by crane). Subsequent use must also be taken into account. It has been shown that large tilting/pivoting sash elements in school buildings often cannot

How sashes move is crucial: A broad tilting sash can cope much better with mechanical loads on the sash and structural component connection than a broad pivoting sash with very high moment at attachment points. If it is correctly installed, the sash frame itself is

meet the demands that their intensive use makes on them if appropriate reinforcement measures have not been taken into account in planning. Horizontal wind loads

Wind loads (wind pressure and suction) are mechanical loads. Wind pressure can impose very large loads on window elements similar to those that live loads impose on a slab. Wind loads also increase the risk of leaks developing, letting in rainwater (see “Humidity protection, sealing, driving rain resistance” p. 59ff.). The DIN EN 14 351-1 product standard for windows and exterior doors

fa

1.5 80 ≈ 80 70 ≈ 100 50 ≈ 100 40 ≈ 40

ab

le

Asymmetrical glazing assembly

Temperature in the space between the panes

ov

1.0

er

lap

pi

ng

1 kPA

Change in air pressure -10 mbar 1 kPA 80 metres elevation 1 kPA

Climate 16.0 kN/m2

2.0

ur

Temperature change +3 K

Load on spacers

vo

Positive pressure

Wind pressure Double and multi-pane insulating glass

Short edge [m]

Un

Exterior air pressure

Negative pressure

Positive pressure

Negative pressure

Wind 0.5 kN/m2 2.5

Overlapping scenarios

possible not possible not possible not possible

0.5

0 0

0.5

1.0

1.5

2.0

3.0 3.5 4.0 Long edge [m] B 1.57

2.5

B 1.56

Property / value / unit Resistance to wind loads Test pressure P1 [Pa]

Classification / figure npd

1 (400)

2 (800)

3 (1,200)

4 (1,600)

5 (2,000)

Exxxx (> 2,000)

Depending on installation site and building height Resistance to wind loads Frame deflection

A (≤ 1/150)

B (≤ 1/200)

C (≤ 1/300)

Not relevant

Typical design specifications for safety criteria

Typical design specifications for serviceability

npd

Impact resistance Fall height [mm]

npd

Load-bearing capacity of safety devices

npd 1

Operating strength 2

npd

Mechanical strength

npd

200

300

450

French doors, glazing where there is a risk of impact in public and commercial applications

French doors, glazing with a risk of impact in private use

700

Threshold value For additional catch stays, locking devices, opening limiters etc. intermittent 350 N load for 60 seconds 1

2

For all uses without special requirements 1

For all uses requiring easy operation

2

3

Not recommended

Long term function, number of cycles

950

Applications usually overlap with technical rules on the use of safety barrier glazing (in Germany, TRAV) (Please note: impact resistance process cannot be transferred to safety barrier requirements)

npd

Private usage

4 Public or commercial areas

5,000

10,000

20,000

Not recommended

Private usage

Public or commercial areas

npd: no performance determined. Figures in brackets are for the purposes of information Only if no safety features, such as catch stays, are included 2 Only for windows opened and closed by hand 1

B 1.58

74

Requirements and protective functions – building physics fundamentals

contains a series of performance features, classes and technical specifications for an element but gives no answers to the question of which requirements are right for a particular construction project. DIN 18 055 gives planners important pointers on these issues. Fig. B 1.58 shows the consequences of wind loads as classified in DIN EN 14 351-1 (mechanical and structural behaviour) and comments on the applications of the classifications. In terms of mechanical behaviour, the resistance of opening limiters and the reveal to impact should also be reviewed (DIN EN 13 126-8). Wind load resistance requirements (testing pressure P1 [Pa] and deflection) will depend on the building’s height, position of windows in the building and the building’s site and positioning. Fig. B 1.59 shows the different steps involved in assessing these loads.

Influence of installation site: 4 wind load zones in Germany, plus special wind loads assumed for very exposed ridge areas etc., see DIN EN 1991-1 + National Appendix (vb, o = basic speed; qb, 0 = basic velocity pressures)

4

4

4

3

3 2 1 2

Horizontal loading capacity, safety barriers

Building openings carry the risk of people falling out of them, not only when they are open, but when they are closed, which parapets and railings in front of or in the opening can protect against (Figs. B 1.60 and B 1.61) [24]. For laminated safety glass parapet elements there are special metal or glass edge protection products that are as thick as the glass and do not disrupt the ‘edgeless’ look. The suitability of glass edge protection products is tested in accordance with DIN 18 008-4. DIN EN 1991-1 (Eurocode 1, formerly DIN 1055-3) requires the following horizontal live load-bearing capacity for rails up to 1.20 m high to be taken into account for floor to ceiling window elements that divide rooms without separate railings (e.g. in public infrastructure), depending on whether the building is open to the public or not: • 0.5 kN/m not generally open to the public • 1.0 kN/m open to the public • 2.0 kN/m (special uses) A higher assumed load resulting from an interaction of forces, such as the structure’s own weight, wind and horizontal live load, is not required; individual peak loads are regarded as decisive in planning and design. In Germany, the federal state building regulations prescribe railing heights that range

Possible deformation of panes of insulating glass due to wind, pressure and temperature variations B 1.57 Application limits of exemplary insulating triple glazing (4/20/4/20/4 mm). The effective climate loads are too great for the glazing of the formats in the red area. B 1.58 Wind loads: mechanical and structural behaviour and classification in accordance with DIN EN 13 126-8, with comments B 1.59 Steps taken in identifying loads on window elements

Influence of installation site: edges of a building exposed to high wind suction loads. While the windward side is exposed to wind pressure, which is critical in designing windows to resist driving rain, windows exposed to wind suction pressure must be designed to accommodate frame deflection.

Wind zone

vb,o [m /s]

qb,o [kN /m2]

WZ 1

22.5

0.32

WZ 2

25.0

0.39

WZ 3

27.5

0.47

WZ 4

30.0

0.56

Building edges: increased wind suction

Building edges: increased wind suction

Wind pressure

Wi

nd

l l/5

Influence of building height: For simplicity’s sake, the building's height is taken into account, not the installation height of windows. There are three height ranges. Windows in buildings higher than 25 m must be designed in accordance with a more complex process specified in DIN EN 1991-1-1-4/NA.

Design standard: whether windows are designed for safety or to ensure serviceability: • Designed to meet safety criteria: required for all components; the window safely survives extreme wind events but may be irreversibly damaged. • Designed to ensure serviceability: Window safely survives extreme wind events and can still be used.

Middle region: wind suction

18– 25 m 10–18 m 0–10 m

l / 300

l / 200

Values for window at risk (10 –18 m, corner) with l/300 + estimated higher wind suction value for corners Examples of designs:

Wind load resistance as defined in EN 12 210

Resistance to driving rain as defined in EN 12 208

Permeability to air as defined in EN 12 207

Window for a house in Würzburg (Wind load zone 1), 6 m high, designed to meet safety criteria

B2 (middle of the building)

4A

2

Window for a house in Hannover (wind load zone 2), 12 m high, designed to ensure serviceability

B4 (edge of the building)

5A

2 ∫ 3 to be selected, because the EnEV is the authoritative standard here

B 1.56

B 1.59

75

Requirements and protective functions – building physics fundamentals

from 90 up to 110 cm depending on the height of possible falls. If railings (e.g. for windows at floor level) or lower railings are absent, additional measures to prevent falls are required. The fixtures of railings or parapets attached to window profiles must have a specific load transfer, i.e. requirements are made on the window profile, the attachment of the railing to the window profile and the attachment of the window profile to the structure. Vertical glazing

DIN 18 008-2 divides glass surfaces into horizontal glazing (formerly overhead glazing) with a gradient of > 10° from the vertical and vertical glazing with a gradient of ≤ 10° from the vertical. [25] Vertical insulating glazing mounted on all sides can be used for installation heights up to 20 metres above ground in normal production and installation conditions without further verification if it fulfils the following prerequisites: • Glass product: plate glass (float glass), annealed glass or single-pane tempered safety glass • Surface area ≤ 1.6 m2 • Thickness of panes ≥ 4 mm • Difference in pane thickness ≤ 4 mm • Space between panes ≤ 16 mm • Wind load w ≤ 0.8 kN/m2

Horizontal glazing

Burglary prevention

DIN 18 008 -2 describes all glazing with a gradient greater than 10° from the vertical as horizontal glazing (formerly called overhead or sloped glazing), regardless of whether it is fixed or can be opened (e.g. roof windows). Fig. B 1.62 describes various possible configurations for such glazing. Divergence from the specifications is only permissible if large glass shards are prevented from falling onto traffic areas and underlying spaces by a net under the window (mesh size ≤ 40 mm, sufficiently loadbearing and durable). Horizontal glazing is subject to deflection limitations as shown in Fig. B 1.63. To prevent standing water on the glass surface, controlled water runoff must be ensured through appropriate sealing. It is generally advisable to make the bottom pane of horizontal glazing out of laminated insulating safety glass at least 8 mm thick. The panes must be mounted free of any tension, and the glass inset should be at least 15 mm. There should be no contact between panes of glass and metals or other panes, not even in the event of extreme temperatures, which requires a minimum spacing of 5 mm. Typical pressure loads, such as wind and snow and (wind) suction loads, must be taken into account. Panes of laminated safety float glass spanning more than 1.20 m must be mounted on all sides.

Analyses carried out by the Bavarian criminal investigation office (Landeskriminalamt) of domestic burglaries through windows show the following distribution of break-in methods [26]: • Window, tilted 2.3 % • Glass broken /climbed through 3.4 % • Cellar light shaft 3.4 % • “Window drill” 4.5 % • Window, open 5.7 % • Glass broken /unlatched 13.6 % • Prying open 66 %

TRAV Category A > 300 mm

1,500 mm

500 mm

250 mm

Parapet height (PH)

Requirement on an element with glazing in the relevant technical rules for glazing category (TRAV – Technische Regeln für die Verwendung von absturzsichernden Verglasungen) Pendulum impact area (for experimental verification) Rail load Fastenings with requirements as specified in the Technical Building Regulations (ETB-Richtlinie – Einheitliche Technische Baubestimmungen) Fastenings without the requirements specified in the Technical Building Regulations (ETB-Richtlinie)

Difference in height (= fall height – FH) TRAV Category C2 > 500 mm

TRAV Category C3 > 500 mm

250 mm

Technical measures can reduce the risk of burglary, regardless of user behaviour. Burglar-resistant structural components in and around openings can impede forced break-ins, even when they are closed, bolted and locked. Distinctions are made between them depending on the attack scenario (e.g. burglar’s method, tools and experience) and period for which a structural component is expected to resist such onslaughts. Burglarresistant windows and doors are manufactured in accordance with binding production specifications, receive a test certificate and must be labelled accordingly. The DIN EN 1627–1630 group of standards classifies different danger zones and specifies technical requirements. After expert consultation with a planner, the client should determine the burglar resistance classes (RC1– RC6) for individual risk situations (e.g. site in the building, transparency of opening elements) in accordance with the scenarios defined in the standard. Fig. B 1.64 (p. 78) can be used as an aid in making this decision. The systems and products used are subject to certain minimum requirements specified in the resistance class. Resistance classes RC2 and RC3 differ in terms of the type and use of specific tools used to break in and permissible period until the structural component gives way (average risk). RC2 and RC3 are recommended for use in dwellings and commercial and public buildings. Class RC2 is divided into two different resistance classes. The addition of “N” to resistance classes RC1 N and RC2 N stands for “national requirement” and means that normal glass without break-in-resistant

250 mm

Rail load > 500 mm

Requirements on structural elements designed to prevent falls and their fastenings to buildings B 1.61 Building regulation requirements on railings, banisters and parapets in various German states (Bundesländer) a LBO S.38 Safety rails (Rhineland-Palatinate) b Ministry of Urban Development and Environment for Building Regulations and Construction Hamburg 3/2013 c MBO 10-2008, Art. 38 Para. 4, Arbeitsstättenrichtlinie (German workplace regulations) 12/1–3 d LBO Schleswig-Holstein B 1.62 Glass options for horizontal glazing B 1.63 Deflection limits of glazing

500 mm 250 mm

PH

500 mm 250 mm

B 1.60

FH B 1.60

76

Requirements and protective functions – building physics fundamentals

90–100 cm

90–110 cm (depending on fall height)

100 cm

60 cm

80 –100 cm

90–100 cm (depending on fall height)

≥ 60 cm

90 –100 cm (depending on fall height)

≤ 60 cm

15–25 cm

≤ 20 cm

a

b

c

d

properties can be used here. There is also a standardised class 2 for normal glass that offers basic protection against prising and levering tools. Special measures to protect against burglary can involve structural components (Fig. B 1.65, p. 79), fasteners and connections between structural components, e.g.: • Optimising screw spacing and screw depths, e.g. screws spaced a maximum of 125 mm apart • Securing screws against unauthorised loosening • Installing additional stainless steel bottom rails to reinforce attachments and profiles • Using tested glass and panels (e.g. break-inresistant and impact-resistant glass) and modifying clamping depths. Their heavier weight may make stronger fittings necessary. • Installing blocks at the sides to prevent panels being moved • Reinforcing frame profiles, glass rails and fittings • Installing lockable window handles (secure handles), connecting rod bolting and protection against levering • Extra safety latches and locks • Protection against drilling in the area where the window moves • Pressure-resistant back lining of the connection to the wall • Securing cellar light shafts

Special safety glazing

glazing in classes A and B. One positive side effect of safety glass (e.g. class P4 A) is that installing it in interiors reduces the risk of injury inside, especially for children, and increases protection against burglary from outside. The goal of bullet-resistant glazing is defined in DIN EN 1063, DIN 52 290 and DIN EN 1522 (class C or C glass) as preventing the penetration of gunshots. Blast resistant glazing as defined in DIN EN 13 541 (class D or D glass) must be able to resist a pressure wave of varying intensity caused by an explosion for longer than normal glass. Glazing, mounting and attachments must be somewhat elastic to meet this requirement. A distinction is also made between glass that does and glass that does not shatter. Shatter-proof glass is used where people may be directly behind glass when it breaks. These types of glazing are generally used in unusual structures in special projects and usually involve specialists in consultation with

B 1.61

The protection that normal glazing offers is not enough for some applications (e.g. buildings housing institutions at particular risk). Special safety glazing is made of different configurations of laminated safety glass (see “Laminated safety glass”, p. 88f.), the structure of which and the requirements on it are defined depending on the protection required. After passing various tests, it is labelled as: Class A: impact-resistant (DIN EN 356) Class B: break-in-resistant (DIN EN 356) Class C: bullet-resistant (DIN EN 1063) Class D: blast-resistant (DIN EN 13 541) DIN EN 356 defines glazing that prevents projectiles from penetrating as impact-resistant (class A or A glass). Break-in-resistant glazing as defined in DIN EN 356 (class B or B glass) must resist a defined number of blows with an axe. Fig. B 1.64, p. 78 shows an overview of

Authorised application

Single-pane toughened safety glass2

Laminated safety glass made with float glass

Single glazing Insulating glazing, upper pane

1

3

Laminated safety glass made with toughened glass 2

‡

‡

‡

Insulating glazing, lower pane 2

Exterior window gratings, especially in lower storeys, offer additional protection but may conflict with aesthetic requirements, so they require special consideration. Burglary-resistant structural components are usually designed for installation in solid walls. DIN 1053-1 specifies typical requirements for brickwork of a nominal thickness of at least 115 mm, bricks with a compressive strength of at least 12 and mortar in group II. DIN 1045 requires steel-reinforced concrete for such purposes to have a nominal thickness of at least 120 mm and be in at least B15 strength class. A specific glass quality is stipulated for each resistance class.

Float glass 1

‡

‡

‡

‡

High-quality, distortion-free glass Also enamelled toughened glass Wired glass and glass with spot-welded wire mesh in panes up to 70 ≈ 250 cm can be used. The span between supports in the main load-bearing direction must be at least 70 cm. B 1.62

Horizontal glazing

Vertical glazing

Four sides

1/100 of the pane span in the main load-bearing direction

No requirement 1

Two or three sides

Single glazing: 1/100 of the pane span in the main load-bearing direction

1/100 of the free edge 2

Panes in an insulating glazing unit: 1/200 of the free edge

1/100 of the free edge 1

2

‡

‡

Mounting

1

Wired glass 3

Deflection limit specifications of insulating glass unit manufacturers must be observed. This limit does not have to be complied with if it can be demonstrated that a pane inset of at least 5 mm is maintained under loading. B 1.63

77

Requirements and protective functions – building physics fundamentals

Resistance class in DIN EN 1627

Resistance class in DIN V EN V 1627:1999

Perpetrator behaviour

RC1 N 1

WK 1

Structural components in resistance class RC1 N offer low levels of protection against the use of levering tools.

–

Opportunistic perpetrator tries to break open a closed and bolted structural element using simple tools such as a screwdriver, pliers and wedges.

–

RC2 N 1

RC2

RC3

–

WK 2

WK 3

Tool contact time as defined in DIN V EN V 1627 [min]

Perpetrator tries to break open a closed and bolted structural element with a second screwdriver, crowbar and simple drilling tools.

Description of pane configuration as defined in DIN EN 356

Typical glass assembly and approximate total thickness [mm]

No requirement defined 2

Recommendations for use (from DIN EN 1627) Residential building

‡

Commer- Commercial /public cial /public building building (high risk) ‡

‡

(low risk /elements that are hard to reach only)

No requirement defined 2

‡

‡

¥

(average risk) 24–27

3

5

P4 A (impactresistant)

‡

P5 A (impactresistant)

‡

‡

¥

(average risk) ‡

¥

(high risk) 27–32

RC4

WK 4

Experienced perpetrators also use cutting and striking tools such as axes, crowbars, hammers, chisels and cordless drills.

10

Experienced perpetrators also use powerful electric tools such as drills, jigsaws, hacksaws and angle grinders.

15

P6 B (break-inresistant)

‡

(low risk) 32–37

RC5

WK 5

P7 B (break-inresistant)

‡

(average risk) 38–46

RC6

WK 6

Experienced perpetrators also use powerful electric tools such as drills, jigsaws, hacksaws and angle grinders.

20

P8 B (break-inresistant))

‡

(high risk) 47–50

‡ yes 1

2

‡ somewhat

¥ no

An “N” added to resistance classes RC1 N and RC2 N stands for “National requirement”. In Germany, glass in Class RC2 N that does not have break-in-resistant properties can be used to provide basic protection against levering tools. This is a cost-efficient way of effectively increasing protection against break-ins. In testing P4 A B 1.64

manufacturers and regulatory authorities. Safety glass can be combined within its classes and in some cases supplemented with other functions (soundproofing, thermal insulation etc.). Depending on its resistance class, it can however be very heavy, weighing up to 180 kg/m2. Increasing the thickness of safety glass panes also reduces its visual transmission (TL) and g value. Resistance to ball impacts (e.g. for sports halls) is not really part of the topic of safety glass, although here too particular demands are made on glazing (resistance to ball impacts as defined in DIN 18 032-3). Other special areas, such as avalanche protection windows and doors (ÖNORM B 5301), will not be dealt with here.

the door or window opens, in front of or behind it. They can also be moveable, forming opening panels that can be rolled up or pushed out. This is advisable if protection against insects is required only at certain times of year. Connections at the edge of the net should not have large gaps. Their small mesh size means that insect protection nets are exposed to wind loads, which must be taken into account. They may also change in length due to thermal elongation. Depending on the design, relatively stiff wire mesh or flexible textile woven mesh, which requires a certain amount of tensioning, may be appropriate here (see “Insect screens”, p. 97).

Insect protection

Barrier-free openings

In some locations, openings need protection against encroaching insects. If this is not provided by ventilator filters, fine nets with a mesh size of 1 to 1.4 mm can offer suitable protection against insects. The goal here is to provide secure protection against insects (especially in summer, in the evening and at night) while allowing sufficient light and air in. Nets can be attached either to the opening element itself (the frame) or directly to the building (e.g. in the reveal), i.e. permanently installed, and, depending on the way

DIN 18 040 makes technical requirements on buildings to be barrier-free. Part 1 covers buildings open to the public, and Part 2 deals with dwellings. “The aim of this standard is to design the built living environment so that it is accessible and enables as many people as possible to use it in a conventional way, without particular impediments and basically without help from others (in compliance with S. 4 of the German Act on Equal Opportunities for People with Disabilities (Behindertengleich-

78

stellungsgesetz))” [27]. It also contains concrete specifications for designing building openings, e.g. for operational elements such as handles (suitable form, height, usually 85 cm, but a maximum of 105 cm above a finished floor) and for movement areas (e.g. in front of doors or windows that are opened and closed manually). Doors generally must be clearly perceptible, easy to open and close (limit of strength required) and safe to pass through. Revolving and swing doors are not barrier-free, so are not suitable as sole access. Closing devices with an uncontrolled closing action (e.g. spring hinges) cannot be installed. Graded minimum door widths and threshold heights (maximum of 2 cm, including for exterior doors) and maximum permissible luminance contrasts are also specified. A number of requirements arise indirectly from the standard, e.g. for people whose vision is impaired, no objects that cannot be felt with a stick should project into the movement area (such as doors or windows that project into a space when open). DIN 18 040-2 contains concrete stipulations for planning windows. Part of a window in a bedroom or living room should provide a view of the building’s surroundings from a sitting position (for windows installed with a lower edge 60 cm above the finished floor at most).

Requirements and protective functions – building physics fundamentals

At least one window in each room must be easy to open and close for people with motor disabilities and wheelchair users, i.e. • The manual strength (operational force) required to open and close this window may be at most 30 N, the maximum moment 5 Nm [28] and • The window handle must be at a height of 85 to 105 cm (above the top of the finished floor). If this is not technically possible, at least one window in the room must have an automatic opening and closing system. Reducing the risk of injury – child-proofing

Glazing, operating elements and other moving parts in and around openings pose a risk of injury. Around the edges of opening elements (closing edges), there is a risk of crushing and severing of hands at their sides and of feet at the bottom. This applies to both manually operated windows and doors and automatic elements with special sensors designed to monitor movement (see “Automatic doors”, p. 141f.). Special solutions are available to keep small children safe, such as finger protection that flexibly covers dangerous joints and prevents small fingers from being caught or crushed in them. Fittings and operating elements should be lockable or inaccessible to small children to reduce the risk of them falling out of windows they have opened by themselves. Openings can also be childproofed by the addition of unreachable bolts and latches, opening limiters (Fig. B 1.66) or similar solutions such as opening panels with seals to protect fingers or integrated finger protection strips.

dependencies on technical lighting issues, such as transmission, reflection, absorption (e.g. in the visual and solar spectral range), energy transfer rate (g value), emissivity, selectivity, greenhouse effect, shading factor (FC value) etc., are dealt with in detail in the section on “Solar and thermal radiation – visible light” (p. 172ff.). The height of openings in a facade is closely connected with a building’s usage. Different dimensions and requirements for building openings allowing users to make use of daylight are regarded as ideal, depending on whether children or adults use the space and whether they use it mainly standing, sitting or lying, for example. DIN 5034-1 on “Daylight in interiors” makes concrete prescriptions for opening heights in dwellings and workplaces. • Bottom edge of transparent parts of a window: maximum 0.95 m above the finished floor • Top edge of transparent parts of a window: minimum 2.20 m above the finished floor • Sum total of the width of all transparent parts of a window: at least 55 % of the width of the living space

3

1 2

4 2 5

2 5

2

6

Barrier-free construction also entails lighting and view requirements. A different viewing height (parapet height of ≤ 60 cm) needs to be taken into account for wheelchair users, for example. In Germany, the building regulations of most federal states specify minimum window sizes (unfinished structural opening) of 1/8 to 1/10 of the room’s floor space to ensure a minimum supply of daylight.

1 2 3 4 5 6

Metal angle Reinforcement Glass-holding cleats Adhesion with 2-component materials Fastening in compliance with the fitting manufacturer’s specifications Closed stiffening profile B 1.65

Colour rendering and the colour rendering index

Lighting and views As well as allowing for ventilation, openings in building envelopes supply interiors with daylight with the following goals: • To provide suitable natural light in an interior while ensuring sufficiently high-quality protection from the sun (adequate brightness level, maximum use of daylight, minimising cooling loads resulting from solar heat input, maintaining the quality of daylight as far as possible and eliminating glare) • To offer views from the inside to the outside • To highlight the structure’s appearance during the day and at night (artificial light inside)

A room’s colour climate is influenced by the spectral composition of incident daylight, which can be modified in its composition and quality by the type of opening, translucent materials (e.g. glass or plastic and added coatings) and by surface reflections (e.g. on reveals). Colour rendering exercises a major influence on our physiological feelings. Daylight contains all spectral colours and makes them look natural.

B 1.64 B 1.65 B 1.66

Connection between resistance classes and pane assemblies, recommended usages Structural features of a break-in-resistant window profile Various ways of securing openings and limiting opening widths, e.g. to protect children

All three goals are closely connected and present a major challenge in practice. Is your sun protection designed so that cooling loads are minimised but the interior can still be used on a hot summer day without artificial light or obscuring views from the inside to the outside? The light and radiation properties of building openings are becoming more and more important. The relevant sizes, requirements and B 1.66

79

Requirements and protective functions – building physics fundamentals

Good colour rendering allows for differentiated perception of colour, enabling people to distinguish colour nuances across the entire spectral range and obtain genuine impressions of colours, and making it a measure of the “naturalness” of daylight entering through an opening. The general colour rendering index Ra is used to identify and specify colour rendering properties as defined in DIN EN 410. The higher the Ra value, the more natural an illuminant’s colour reproduction is. Ra values of > 90 indicate illuminants with very good and Ra > 81 with good colour rendering. An artificial light source with a colour rendering index of 100 shows all colours optimally. Colour rendering is important for sampling colours in the textiles and graphics industries, in dental laboratories and in operating theatres. Glazing in building openings changes the spectral composition of incident daylight to varying extents, depending on the glass and its coating. The standard light type D65 serves as a reference illuminant and provides light equivalent to that of daylight with a grey sky or the sky at midday seen from a north-facing window with a colour temperature of 6,504 K. The colour rendering index Ra, D measures the congruence of the spectral composition of light in front of and behind glazing in building openings, incident daylight and visibility through the glass. The maximum Ra, D figure is 100, i.e. there is no colour distortion in transmission. Uncoated, low-iron glass (clear glass) up to 8 mm thick achieves this maximum. Its spectral transmission in the visible range is almost completely constant. A curve in the visible light range as shown in Fig. C 1.13 a (p. 174) would be almost completely horizontal. Translucency is decreased but is reduced completely evenly across the wavelength range of visible light. It is this evenness that Ra, D measures. Normal, uncoated, 6 mm thick float glass has a Ra, D value of 98; coated standard insulating glass typically has a Ra, D value of > 93. The Ra, R value measures the colour rendering of glass on the external viewing side, i.e. the modification in colours of light seen in reflection. This can affect views from outside (e.g. the extent to which reflections on coated glass seen from the outside can change a viewer’s impression of colour) and the reflection of artificial light on the inside. The Ra, R values for the two sides of glass, especially coated glass, can be different from each other and from the Ra, D value. Criteria used in evaluating and assessing glazing Accepting glazing as part of overall construction work involves determining whether the quality provided is free of defects or not. If there are defects, the question of how they occurred must be answered. Did builders ignore certain requirements and are they now obliged to remedy the defects, e.g. by replacing glazing?

80

Optical requirements

Optical distortions can result from concave or convex bulges in panes. Possible causes are fluctuations in pressure and temperature or divergence from the originally planned installation site for which the pressure of the gas filling in the space between the panes was designed during manufacture (see “Mechanical requirements”, p. 73, and Fig. B 1.56). Various causes can also impair the quality of a glass surface: • Changed surface tension can cause surfaces to react differently to wetting, becoming visible when it rains and resulting in inconsistent soiling. A possible cause is the contact of panes of glass with suction cups, stickers or the like. This is not usually a reason to reject glazing; the effect can be eliminated (with some effort) if necessary. • Chemical impacts e.g. from lime washing out (of concrete or cement mortar), mineral paints or strongly alkaline detergents can irreversibly damage a glass surface. This may represent a defect in planning or maintenance. • Anisotropy (dark streaks, rings, “iridescence”) is a physical effect in heat-treated glass caused by unequal inner tension and depends on the viewing angle (especially when seen from flat angles), weather and the height of the sun. This is an unavoidable by-product of the manufacturing process and not a defect. Mechanical damage

Glass is often damaged due to mechanical impact, which can be prevented by properly handling glass on the building site and other safety measures. • Scratches caused during manufacture or transport, incorrect cleaning, mistakes made during installation or subsequent work by other tradesmen can be avoided by using protective measures such as foils or other appropriate temporary covers. • Nicks from angle grinders, welding splashes and burned-in particles from angle grinding or welding can impair glass surfaces. They occur due to a lack of, or inappropriate, covering or other protective measures. It must be ensured that work is done at a sufficient distance from glazing on the building site. Checks or internal acceptance after critical work is completed by other tradesmen are also advisable. • Damage from stones and local spalling due to small stones that hit but do not break glass can occur during transport to the building site. • Vandalism represents a danger to glass in its installed state. Prestressed glass (laminated safety glass and tempered safety glass) does not generally scratch more easily than float glass. Scratches in prestressed panes occur in the same way

but can spread later due to compressive stresses on the surface, thereby becoming more clearly visible. Checking and evaluating glazing

“Normal use” is usually the decisive consideration in the optical checking and evaluation of the glazing of a window or door element, which is done as part of acceptance by clients or with an expert report [29]. This means specifically that: • Visibility through the glazing with the view of the background is the essential criterion, not the view on the glass surface. • Evaluation is carried out at a minimum distance of 1 m from the inside looking out from a viewing angle in keeping with the typical use of the space. • Glazing is tested under diffuse daylight (on a cloudy day) without direct sunlight or artificial lighting. • The exterior view of glazing is evaluated in its installed state at viewing distances typical for normal use. This rarely involves distances of less than 1 m. Panes are also divided into individual zones as shown in Fig. B 1.67, to which differing requirements apply (Fig. B 1.68).

Dimensions and tolerances Generally, binding dimensions are indispensable in the planning, manufacture and installation of opening elements, in building the necessary openings in buildings and in the entire construction process. This applies to both new buildings and to construction involving existing buildings. Fig. B 1.69 shows the dimensions usually specified for openings. The most important are • Frame exterior dimensions • Clear opening measurement • Clear sash measurement • Glass dimensions • Sash frame dimensions • Shell dimensions (nominal dimensions on the plan) Every installation situation and the manufacture of structural elements and components must ensure that they can absorb tolerances without impairing their function. Permissible variations in dimensions can have various causes. DIN 18 202 classifies tolerances as follows (Fig. B 1.70, p. 82): • Deviation of actual from nominal dimensions • Limiting deviations • Angular tolerances • Evenness tolerances • Misalignments With regard to tolerances, the dimensions of structures in their unfinished state are nominal dimensions, i.e. dimensions that are planned

Requirements and protective functions – building physics fundamentals

Pane width

B 1.67

F

R

B 1.68

Pane height

b/10 F

Main zone H

Clear height h

b/10

F

F

h/10

Clear width b

Main zone H

F

h/10

but that can diverge from actual dimensions. DIN 18 202 also defines permissible deviation limits, especially for building openings, making a distinction between the range of nominal dimensions and the extent of development (Fig. B 1.71, p. 83). Various rebate types (see p. 124f.) must be taken into account (without rebate, inner or outer rebate) in planning the dimensions of building openings. In practice, the dimensions of windows and doors play a major role in new buildings in particular because they are usually manufactured before the relevant installation situation develops. Existing buildings have openings, but their structural situation is often not entirely amenable to inspection (because the old windows are still in place), so complex geometries (oblique angles, curved edges, uneven joint surfaces etc.) often mean that in practice the external dimensions of the reveal are frequently 10 – 30 mm less than the dimension of openings in their unfinished state (nominal dimension). There are currently no normative standards for tolerances for prefabricated complete window elements. The exterior element dimensions of window elements subject to RAL quality control [30] must have a tolerance of 1 mm.

H

Division of a pane into various zones with different evaluation requirements Permissible visual qualities of glass products for use in construction, descriptions of zones referred to in Fig. B 1.67

Rebate zone F: the area covered and not visible when the pane is installed (except mechanical damage to edges – no restrictions) Edge zone R: circumferential, 10 % of clear widths and heights (less stringent evaluation) Main zone H: most stringent evaluation B 1.67

Zone

Permissible per unit:

F

External shallow damage to edges or conchoidal fractures that do not impair the glass’s strength and do not project beyond the sealed edge

Movement-compensating potential

Building openings “break up” the homogeneous fabric of an opaque building envelope. Installing them involves joints, a change of materials and structural transitions in the building and the opening elements themselves. Appropriate planning must avoid possible constraining forces here, which can have the following causes: • Deformation during installation • Deformation in the building (due to changes to loading during construction or subsequent live loads) • Deformation due to wind loads (suction and pressure) • Linear expansion due to thermal expansion (differences in temperature of up to 100 K) or swelling /contraction • Pressure resulting from ice formation

Internal conchoidal fractures without loose shards that are filled with sealant Punctiform and shallow defects and scratches – unlimited R

Inclusions, bubbles, spots, blotches etc.: Pane area ≤ 1 m2: max. 4 pieces à < 3 mm Pane area > 1 m2: max. 1 piece à < 3 mm for each circumferential metre of edge length Defects (punctiform) in the space between the panes: Pane area ≤ 1 m2: max. 4 pieces à < 3 mm Pane area > 1 m2: max. 1 pieces à < 3 mm for each circumferential metre of edge length Defects (shallow) in the space between the panes: max. 1 piece ≤ 3 cm2 Scratches: total individual lengths: max. 90 mm – individual lengths: max. 30 mm Hairline scratches: not permitted in clusters

H

Inclusions, bubbles, spots, blotches etc.: Pane area ≤ 1 m2: max. 2 pieces à < 2 mm 1 m2 < pane area ≤ 2 m2: max. 3 pieces à < 2 mm Pane area > 2 m2: max. 5 pieces à < 2 mm Scratches: total individual lengths: max. 45 mm – individual lengths: max. 15 mm

Constraining forces in and around an opening can lead to reversible or irreversible deformation, permeability to wind and rain, noises resulting from deformation and cracks, and spalling of adjoining structural components (e.g. plaster on and around frames). The mounting parts of windows and doors must therefore fulfil the following criteria: • Mounting on sliding and fixed points (avoiding the use of several fixed points) • Expansion joints between elements depending on their dimensions and material properties (e.g. between large adjoining window elements) • Structural joints must be permanently sealed by appropriate connections and usually mean that soundproofing has to be improved (see “Joints in building envelopes”, p. 63f.).

Hairline scratches: not permitted in clusters R+H

Maximum number of permitted defects as for Zone R Inclusions, bubbles, spots, blotches etc. 0.5 to < 1 mm are permitted without surface limitations but not in clusters. A cluster is at least 4 inclusions, bubbles, spots, blotches etc. in a circular area with a diameter of ≤ 20 cm.

Notes: Objections ≤ 0.5 mm are not taken into account. Existing interference fields (yard) may not be greater than 3 mm. Permissible defects in triple insulating glass, laminated glass and laminated safety glass: The frequency of permissible defects for zones R and H may increase for each additional pane of glass and each laminated glass unit by 25 % of the specified value. The result is always rounded up. Toughened safety glass and annealed glass and laminated glass and laminated safety glass made with toughened safety glass and/or annealed glass: 1. Local ripples on the glass surface may not exceed 0.3 mm over a 300 mm section except in toughened safety glass made of ornamental glass and annealed glass made of ornamental glass. 2. Distortions may not exceed 3 mm per 1,000 mm of the glass edge length, except for toughened safety glass made of ornamental glass and annealed glass made of ornamental glass. Greater distortions are permissible in quadratic formats and approximately quadratic formats (up to 1:1.5) and in single panes with a nominal thickness 1 ≤3 ± 12

>3 ≤6 ± 16

>6 ≤ 15 ± 20

>15 ≤ 30 ± 24

Construction Products Regulation

The European construction products regulation (EU Regulation No. 305/2011) came fully into force in July 2013 and applies equally to all European member states. It prescribes conditions for putting construction products on the market and regulates the performance specifications of construction products that manufacturers must provide and the use of CE labels. All construction products covered by harmonised standards (visit www.DIBt.de for a list) and those for which the manufacturer holds a European Technical Assessment (previously ‘approval’) must have a performance declaration containing specific details on the manufacturer and product and be signed by the manufacturer. Individual, harmonised European product standards regulate

Material

> 30 1

± 30

Dimensions in elevation, e.g. storey heights, platform heights, spacing of contact areas and corbels

± 10

± 16

± 16

± 20

± 30

± 30

Clear dimensions in the floor plan, e.g. dimensions between columns, pillars etc.

± 12

± 16

± 20

± 24

± 30

–

Coefficient of thermal expansion αT [mm/mK]

Glass

0.009

Steel

0.012

Aluminium

0.024

Polycarbonate

0.065

PVC-hard

0.080

PMMA

0.070 – 0.090 B 1.72

Material (window profile)

Clear dimensions in the elevation, e.g. under ceilings and beams

± 16

Openings, e.g. windows, doors, built-in elements

± 10

± 12

± 16

–

–

–

Openings as above, but with reveals with finished surfaces

±8

± 10

± 12

–

–

–

1

contribution for improving energy efficiency? What part should tenants play? Who should profit and to what extent from government subsidies, lower operating costs (ancillary costs) and increased comfort? The chapter on “Life-cycle assessments for windows and exterior doors” deals with environmental requirements in more detail (p. 208ff.)

± 20

± 20

± 30

–

–

These limit deviations can be applied to nominal dimensions up to about 60 m. Special measures are required for larger dimensions. B 1.71

ε [mm/m]

PVC hard (white)

1.6

PVC hard (coloured) and PMMA (coloured co-extruded)

2.4

PU integral hard foam

1.0

Insulated aluminium profile (light)

1.2

Insulated aluminium profile (dark)

1.3

Steel profile

0.6 B 1.73

83

Requirements and protective functions – building physics fundamentals

Structural component / structural component layer / material

Service life [a]

Average service life [a]

Non-load-bearing exterior structure Concrete, exposed to weather

60 – 80

70

Concrete, clad

100 –150

120

Natural stone, exposed to weather

60 – 250

80

Clinker brick, exposed to weather

80 –150

90

Clinker brick, clad

100 –150

120

Calcium silicate or sand-lime brick, exposed to weather

50 – 80

65

Calcium silicate or sand-lime brick, clad

100 –150

120

Lightweight concrete, clad

80 –120

100

Joint

20 – 50

40

Soft wood, exposed to weather

40 – 50

45

Hard wood, exposed to weather

60 – 80

70

Sealing against water not exerting pressure

30 – 60

40

Thermal insulation, ventilated

25 – 35

30

Natural stone

60 –150

80

Clinker brick

80 –150

90

Concrete, prefabricated concrete components, ceramic, tiles, artificial stone

60 – 80

70

Copper sheeting

40 –100

50

Aluminium, galvanised steel, fibre cement

30 – 50

40

which main product features must be individually specified for each construction product. Windows, exterior doors, panes of glass and curtain facades are subject to these harmonised product standards, so they must bear CE labels. The building laws of member states define which features performance must be declared. For features that do not have to be declared, the manufacturer can declare “npd” (“no performance defined”). All the values in the performance declaration must also be listed on the CE label. The CE labelling of construction products is therefore now far more performance-oriented than it was. This means that for each product, a performance declaration from the manufacturer or retailer is available to consumers in their own language that makes it clear for which application it is designed and which performance features it has. Whether the product is suitable for the planned use and whether its performance features are sufficient to satisfy the requirements at the installation site is a decision that must ultimately be taken by the planner or client.

Wall and parapet covers, windowsills, exterior

Plastic

15 – 30

20

Zinc sheeting, cement plaster

20 – 30

25

Hard wood, aluminium

40 – 60

50

Soft wood

30 – 50

40

Steel, galvanised

40 – 50

45

Plastic

40 – 60

50

Single-pane glazing

60 –100

80

Multi-pane insulating glazing

20 – 30

25

8 –15

10

Exterior doors and windows / frames / casement frames

Exterior doors and windows / glazing, sealing

Putty Glass sealed with a sealing profile

15 – 25

20

Glass sealed with sealant (silicone or the like)

10 – 25

12

Casement sealing profile

15 – 25

18

Roof light dome (roof)

20 – 30

25

Simple fittings

30 – 50

40

Turn / tilt, lift / tilt, pivot and sliding fittings

20 – 30

25

Door latch/lock

20 – 30

25

Door closer

20 – 30

22

Fixed, made of lightweight metal

50 –100

60

Mobile, aluminium or plastic

20 – 30

25

Awnings

10 – 20

15

Notes: [1] The chapter contains information and material from various ift Rosenheim publications, especially from, Jehl, Wolfgang: Montageleitfaden, incl. Montagetaschenbuch – Leitfaden zur Planung und Ausführung der Montage von Fenstern und Haustüren für Neubau und Renovierung, published by the RAL-Gütegemeinschaft Fenster und Haustüren e. V., compiled by the RAL-Gütegemeinschaft Fenster und Haustüren e. V. and ift Rosenheim, 03/2014 [2] See also publications from the ift Rosenheim on this topic, in particular, Sieberath, Ulrich; Leuschner, Ingo; Benitz-Wildenburg, Jürgen: Hochwasserschäden an Fenstern, Türen und Verglasungen. Schadensbilder und Sanierungssätze, ifz info FE-15/1. ift Rosenheim 04/2014 [3] EnEV 2014 Appendix 3, Table 1 [4] The three options that the EnEV offers are explained in detail and illustrated with examples in [1], p. 68 – 77. Here there are also examples for existing buildings and extracts from the ift-Wärmebrückenkatalog (catalogue of thermal bridges). [5] On the topic of comfort in interiors see also DIN EN 15 251, DIN EN ISO 7730 and VDI guideline 3787 [6] To calculate the operative temperature of a room and its enclosing surfaces with which users exchange radiation, the room is divided into two “half rooms” the same size for the sake of simplicity. In the sample calculation, the results of which are shown in Figs. B 1.19

Exterior doors and windows / fittings

Exterior doors and windows / outside sunscreens

B 1.74

84

Requirements and protective functions – building physics fundamentals

Structural component quality

Environment

Conditions of use

A

Quality of components

Manufacturing method, storage, transport conditions, materials, protective coatings

B

Quality of construction

Joint, structural protection

C

Quality of building work

D

Interior influences

Air conditions in the room

E

Exterior influences

Weather, ground motion, outdoor air quality

F

Intensity of use

Mechanical impacts, type of usage, wear and tear

G

Quality of maintenance

Type and frequency of maintenance, accessibility

Which results in: ESLC = RSLC ≈ A ≈ B ≈ C ≈ D ≈ E ≈ F ≈ G ESLC = estimated service life of a component RSLC = reference service life of a component

[7]

[8]

[9]

[10]

[11]

[12] [13] [14]

[15]

and B 1.20 (p. 56), the ‘half room’ is the sametemperature as the facade, while the other shows all interior structural elements, which are also assumed to have a consistent temperature. In reality, temperatures vary across facade surfaces and inside rooms, e.g. when the sun is or has been shining on areas. DIN 4108-3 Thermal protection and energy economy in buildings – Part 3: Protection against moisture subject to climate conditions – Requirements and directions for design and construction The topic is comprehensively dealt with in Hellwig, Runa Tabea: Thermische Behaglichkeit. Dissertation, TUM University 2005 The length of time it takes for mould to form depends on a wide range of site-specific conditions: • Porosity of the surface (the more porous the surface, the greater the risk of mould forming) • Nutrient content in the air and direct environment • Density of spores in the air • Weather (the risk is higher for example in early November than in June) As Note 1, also Froelich, Hans; Lass, Gisa: “Tauwasserbildung an Fenstern und Außentüren, Beurteilung und Vermeidung” and “Leitfaden zur Vorbeugung, Untersuchung, Bewertung und Sanierung von Schimmelpilzwachstum in Innenräumen”, info 4/05 from the ift Rosenheim / Umweltbundesamt, 2005 DIN 4108-2 section 6 “Minimum requirements for the thermal insulation of components and in the area of thermal bridges” Herzog, Thomas et al.: Facade Construction Manual. Basel 2004, p. 24 ibid. DIN EN 12 354-3 “Building acoustics – Estimation of acoustic performance of buildings from the performance of elements – Part 3: Airborne sound insulation against outdoor sound” and DIN EN 12 354-4 “Building acoustics – Estimation of acoustic performance of buildings from the performance of elements – Part 4: Transmission of indoor sound to the outside” contain further information on soundproofing. For new buildings, DIN 4109 is generally binding, although this standard has been under review for some time. An initial draft of the new standard was published in July 2013. Application of VDI guideline 2719 “Sound insulation of windows and their auxiliary equipment” or 4100 “Sound insulation between rooms in buildings – Dwellings” can be agreed on in cases in which DIN 4109 does not apply or specifies too few requirements. Soundproofing in buildings and structural components is evaluated in compliance with EN ISO 717-1. A single numerical value measured in dB (A) is obtained by adding the energy of sound levels in the various octave and third-octave bands. Because human hearing does not perceive deeper sounds ( 8 kHz), adding the sound levels in the various octave bands shuts

B 1.75

[16] [17] [18] [19]

[20] [21]

[22]

[23]

[24]

[25]

[26] [27] [28]

[29]

[30]

[31]

out more deep sounds than middle and higher sounds. The sound levels in the octave bands are corrected in keeping with the ability of human hearing to perceive them. DIN 4109 Supplement 1, Paragraph 10.1.2, p. 55 VDI guideline 2719 Paragraph 2.5 Saß, Bernd: Schalldämmung von Dreifach-Isolierglas. Lecture at DAGA, Berlin 2009 Official classification in the DIBt Construction Products Lists, p. 71f. www.dibt.de/de/Geschaeftsfelder/ data/BRL_2014_1.pdf (as of 30.03.2015) Identification letters and times as shown in DIN EN 13 501-2, Part 7 cp. Brandschutz-Arbeitshilfe “61.3 Europäisches Klassifizierungssystem”, as of 09/2008, Bauen mit Stahl. www.bauforumstahl.de/upload/documents/ brandschutz/arbeitshilfen/BA_61_3.pdf (as of 30.03.2015) More information is available in Mink, Hans-Paul: Brandschutz im Detail – Türen, Tore, Fenster – Planung, Montage, Abnahme, Wartung. Cologne 2010 Gressmann, Michael; Pahl, Hans-Joachim; Spaag, Andreas: Fenster-, Türen- und Fassadentechnik. Haan-Gruiten 2012, p. 22f. See DIN 18 008-4, formerly Technical rules for the use of safety barrier glazing (TRAV), Deutsches Institut für Bautechnik (DIBt), 01/2003 DIN 18 008-2 covers glazing dimensions and has been the applicable glass dimension standard since 2010. Before that the issue was regulated by the Technical rules for the use of glazing on linear supports (TRLV) issued by the German Institute for Structural Engineering (Deutsches Institut für Bautechnik - DIBt), 08/2006 Landeskriminalamt Munich, 2008 Foreword of DIN 18 040-1:2010-10 In accordance with DIN EN 13 115 “Windows – Classification of mechanical properties – racking, torsion and operating forces” class 2 Testing and evaluation criteria can be found in the “Richtlinie zur Beurteilung der visuellen Qualität von Glas für das Bauwesen” (Guideline for assessing the visual quality of glass in buildings), issued by the Technischer Beirat im Institut des Glaserhandwerks für Verglasungstechnik und Fensterbau, Hadamar and the Technischer Ausschuss des Bundesverband Flachglas e. V., Troisdorf (as of 05/2009). This is an industry guideline, so it cannot be used as a generally accepted technical regulation. The RAL Deutsches Institut für Gütesicherung und Kennzeichnung e. V. is an independent organisation that issues RAL “quality marks” for products and services depending on quality criteria specific to certain products and services. Manufacturers voluntarily comply with the commitments involved in RAL quality monitoring so as to be able to advertise products and services complying with this quality standard. See also König, Holger et al.: Lebenszyklusanalyse in der Gebäudeplanung. Munich 2009

B 1.74

B 1.75

Expected service life of components and materials in and around openings in building envelopes Service life of a structural component, estimated using the factor analysis method in accordance with ISO 15 686

85

Materials, components, types of construction Jan Cremers

B 2.1

Windows and other opening structural elements in building envelopes consist of a range of individual elements, which will be explained below, moving from inside to out, beginning with the materials used to cover and close up openings such as glass, translucent or opaque panels etc., continuing with the frames made of various materials that usually hold these planar structural components and concluding with fittings and materials for joining components. The next section opens with an overview of typical window structures, followed by descriptions of solutions (again at the component level) that can be used to create particular properties, including soundproofing and fire protection. The chapter concludes with other added or integrated elements such as motors, sensors and the like.

Glass as a filling material From the earliest period of the history of construction, people have looked for ways to close openings in building envelopes while retaining their most important properties, letting in light and providing views (even when the opening is closed) as well as controlling the exchange of air through the opening and offering a certain degree of thermal insulation (see “The historic development of the window – from its origins through to the early modern era”, p. 12ff.).

Mechanical properties

B 2.1 B 2.2

B 2.3 B 2.4

Fibreglass plastic window profiles as semifinished product Properties of soda-lime glass in float glass, annealed glass, toughened safety glass and multi-pane insulating glass (MIG), values for 2014 Manufacture of glass products for openings From basic to functional glass: possibilities for further processing flat glass

2.5 g/cm3 Density Scratch hardness on the Mohs scale 5–6 Tensile strength 30 – 90 N/mm2 Compressive strength 700–900 N/mm2 Bending tensile strength – float glass 45 N/mm2 Bending tensile strength – annealed glass 70 N/mm2 Bending tensile strength – toughened 120 N/mm2 safety glass E-module 70,000 N/mm2 Under tension, linear expansion to breaking point Optical properties Light transmission float glass 4 mm Solar transmission float glass 4 mm Surface emissivity ε Refractive index Thermal properties Thermal conductivity Specific thermal capacity

approx. 87 % approx. 80 % approx. 89 % approx. 1.5 0.80 W/mK 720 – 800 J/kgK

Wood (in lattice structures or as closed surfaces such as shutters), grass, straw and reeds, specially worked natural stone (including translucent ones such as alabaster), ceramic materials (e.g. fired clay), metals (as sheeting, rods and grilles), textiles, leather, parchment or even paper and more recently plastics have all been used as filling materials. Glass is still of paramount importance as a material for closing building openings and has been used for this purpose at least since the Roman period (see “A brief, yet unsustainable flourishing”, p. 13). To make the soda-lime glass now generally used in construction, a mixture of 72 % of a glass-forming substance (quartz sand / silica), 14 % flux agent (soda), 10 % stabiliser (lime) and certain oxides (magnesium or aluminium oxide) to improve its physical properties is heated to approx. 1,550 °C and melted. This inorganic molten material does not crystallise when cooled quickly, so glass continues to behave like a liquid when it hardens. Glass’s unordered molecular structure is the physical prerequisite for its central property – transparency. During the manufacturing process, glass can also be dyed, although this changes its optical qualities such as its light transmission level. Glass’s inherent pale green colour can be reduced or almost eliminated by the careful

Resistance to temperature differences 40 K across the pane (float glass) Resistance to temperature differences 150 K across the pane (toughened safety glass) Thermal expansion 0.009 mm /mK Softening temperature approx. 560 °C Ug value, single pane 4 mm 5.8 W/m2K Other properties Sound insulation, float glass 3 mm approx. 22 – 24 dB electrical conductivity (dry) Isolator up to approx. 600 °C gas-tight Gas density (incl. H2O) 2, 3, 4, 5, 6, 8, 10, Standard glass thicknesses, 12, 15, 19 mm flat glass 3,210 ≈ 6,000 mm Standard float glass – panel 3,210 mm ≈ Maximum float glass format approx. 16 m (incl. coated) 3,210 mm ≈ 15 m Max. format for toughened / annealed glass Max. format for MIG 3,210 mm ≈ 15 m (double) B 2.2

86

Materials, components, types of construction

Glass products for facades Cast glass (rolling process)

Pressed glass

Cross section profiling

Surface profiling

1st level (Primary shaping)

Sheet glass (drawn glass)

Float glass

Metal inlay 2nd level (Reshaping as part of the manufacturing process)

Prestressed Lamination

Adhered with spacers Hollow glass bricks, concrete glass

Profiled glass

Cast glass, ornamental glass

Wired glass

Single glass

Single-pane toughened safety glass /annealed glass panes

Laminated safety glass panes

Insulating glass

3rd level (Refining, finishing) B 2.3

selection of raw materials, e.g. by using a lower proportion of iron oxide (Fe2O3), which is referred to as low-iron or extra-white glass and costs about 30 % more than ordinary glass. Using glass of this quality, especially in thick glass structures or where there are several panes together with a high total thickness, will increase transparency significantly (Fig. B 3.76 a, p. 147). Since it is a purely mineral material, glass is not flammable and has no predefined melting point. It becomes malleable above its softening temperature (approx. 560 °C). Increasing its temperature further reduces its viscosity. Glass is very resistant to alkaline solutions and acids (apart from hydrofluoric acid). It has a fairly hard surface, so it is more durable and robust than alternative transparent materials, including plastics such as polycarbonate (PC), polymethylmethacrylate (PMMA) or ethylene tetrafluorethylene (ETFE). Like metal, glass of and above a certain thickness is absolutely gas-tight. Fig. B 2.2 illustrates some of glass’s other properties. Wired glass

Wired glass is a special cast glass with an embedded wire netting. If it breaks, shards stick to its wire netting. Since it does not have the greater mechanical strength of toughened safety glass or any safety features as defined in the DIN 18 361 standard, it is not formally regarded as safety glass. It is often used as ornamental glass with a profiled surface, which limits the view through it. Wired glass is often used for its appearance, as fire-resistant glazing (fire resistance class G30), as shatterproof glazing in roofs with a maximum span of < 100 cm or in vertical glazing 180 – 200 cm above the floor away from traffic areas. Like polished wired glass (DIN EN 572-3), which was formerly known as wired mirror glass, the optical quality of wired glass is not as good as that of float glass because it is not as flat and even. The maximum size of a pane of wired glass is typically 3,820 mm long and 1,980 mm wide with a nominal thickness ranging from 6 to 10 mm.

Flat glass

Flat glass for construction is manufactured using three main primary shaping processes (Fig. B 2.3): a rolling process (cast glass), the Fourcault process (sheet, plate or drawn glass) developed in 1904, and the float method (float glass) invented in 1958. Industry has been using the latter since the 1960s, and it is now used to produce 95 % of all flat glass. The float method involves pouring molten glass onto a bed of liquid tin and cooling it until the glass can be removed in solid form. The result is very plane-parallel, distortion-free flat glass. The glass’s thickness (approx. 0.5 –25 mm) depends on the speed at which the solid glass is drawn out of the semi-liquid mass. As float glass is the source material used for making many other glass products with particular functional properties, it is also called ‘basic glass’ (Fig. B 2.4). Further processing of float glass

Float glass is almost always processed further to improve its functional or design properties. Often several methods are used to process panes of glass before different panes are joined or combined to form functional units.

Annealed, tempered and toughened glass Tempered or toughened glass as defined in DIN EN 12 150-1 is float glass that is heated to about 600 – 650 °C then cooled abruptly with cold air. This cools its surface quickly, but the pane’s core initially remains viscous and only contracts later during further cooling. This special thermal treatment creates tensile stress on the inside and compressive stress on the surface that toughen the glass, making it more impact-resistant, elastic and less sensitive to changes in temperature than normal float glass. If it breaks, the energy stored in the tension is released and the glass shatters suddenly into small, harmless blunt pieces that present little risk of injury (Fig. B 2.6, p. 88). If toughened glass is installed in areas in which it is exposed to large temperature fluctuations (e.g. rear-ventilated exterior wall cladding), DIN 18 516-4 stipulates that it must undergo a heat-soak test before installation to minimise the risk of the pane shattering without any apparent exterior action. Panes can spontaneously shatter when nickel-sulphide inclusions in the glass matrix are warmed by the sun and expand. If the pane passes the test in controlled conditions without damage, it is unlikely to subsequently shatter spontaneously.

Thermal pre-stressing

Safety glass

Adhesion of surfaces

Sound insulating glass

Enamelling

Fire protection glass

Etching

Sandblasting

Multi-pane glazing

Optically variable / translucent glass

Printing

Coating

Glass that protects against sun and heat B 2.4

87

Materials, components, types of construction

Annealed glass as defined in DIN EN 1863 is cooled more slowly, so the tension in it is less and it breaks into much larger shards. Annealed glass can be useful for applications for which the mechanical strength of float glass is not enough but toughened glass does not have the required remaining load-bearing capacity because of its crumbly structure when it breaks (e.g. point-fixed panes in overhead applications). If annealed glass is mounted or clamped on all sides, no dangerous shards are loosed when it breaks. In practice, it is not usually installed in single panes but is used in laminated safety glass. Only in this processed form is it formally classified as safety glass.

Cleaning

Due to the tempering process, toughened and annealed glass cannot be subsequently sanded, ground, cut or drilled. Damage to its surface, e.g. chipped edges due to improper transport, will cause the pane to break. Low-E coating systems that can resist the heat of the tempering process (up to 720 °C), and so can be applied in advance, are now also available (see “Lowemissivity coatings”, p. 52). Depending on your position, angle of observation and the incident light, coloured effects can occur in the form of small circles, usually in lines, in toughened panes of glass in their installed state. This is anisotropy and is caused

Heating

Cooling B 2.5

Cooling during manufacture

Single-pane toughened safety glass

Annealed glass

Very fast

Fast 2

Very high 120 N/mm2

Bending tensile strength

Very high 120 N/mm

Resistance to temperature differences across the pane

Very high 150 – 200 K

High, up to 100 K

Breaking behaviour

Blunt shards < 1 cm2

Breaks into large pieces from edge to edge

Fracture pattern

B 2.6

- Pressure + Tension Chemically pre-stressed glass Pre-stressing

Glass thickness

Thermally pre-stressed glass (single pane toughened safety glass) B 2.7

1 2 1 1 Glass 2 Intermediate layer / foil(s) B 2.8

B 2.9

88

by the double refraction of light. It is an inherent physical property of the glass and not a defect. Chemically strengthened glass Very thin and curved glass can also be toughened by being submersed in hot molten salts. The chemical process creates compressive tension on the surface. The submersion process also toughens the pane’s edges. Chemically strengthened glass as defined in DIN EN 12 337 is highly resistant to thermal and mechanical loads, and its fracture behaviour is similar to that of float glass. It has a bending tensile strength of approx. 200 N/mm2 [1]. Unlike toughened and annealed glass, chemically strengthened glass can be cut, although its cut edge is only as strong as normal glass. Fig. B 2.7 shows the distribution of tension across chemically strengthened glass compared with other toughened glass. Laminated safety glass Laminated safety glass is made by laminating individual (including curving) parallel panes of float glass, toughened glass or annealed glass with polyvinyl butyral (PVB) foils between them (Fig. B 2.8). Extremely tear-resistant, tough and elastic, PVB is melted under high pressure (> 10 bar) and at high temperatures (> 100 °C) in an autoclave and bonded onto transparent panes. This creates a strong bond, so that the glass sticks to the foil when it breaks. No dangerous shards are loosened, and the opening remains closed and largely transparent. Various combinations of panes and foils are available for different applications (typically 0.38 mm per layer or multiples of that figure, up to 1.52 mm, translucent, opaque, coloured, with patterns or embedded textiles and the like; Fig. B 2.9). Its mechanical strength can be significantly increased so that it can provide protection against break-ins (see p. 76f.) or a bulletproof effect (see “Special safety glazing”, p. 77f.). Laminated safety glass with at least four panes and a total thickness of ≥ 25 mm is called bulletproof glass. The change in materials and bond in these panes also improves their soundproofing qualities. In installing thick laminated safety glass, its high weight per unit area and the potential for optical distortions due to the different light refracting behaviour of individual layers must be taken into account. Standard PVB foil adhered to float glass almost completely blocks UV light, which can be advantageous for some applications (e.g. museums). Alternative foil materials from approx. 320 nm that let through UV light, which is essential to various biological processes, are also available. As an alternative to PVB, special foils made of thermoplastic polymers with total nominal thicknesses ranging from 0.89 to 3.04 mm are now available that are up to five times stronger and a hundred times more rigid than ordinary

Materials, components, types of construction

PVB interlayers. This means that thinner and lighter laminated safety glass can be manufactured, with the laminates meeting the same safety standards as thicker laminated safety glass with intermediate PVB layers. Laminated glass Laminated glass is similar in structure to laminated safety glass although its interlayer material is not PVB foils, but casting resin 1 to 4 mm thick or ethylene-vinyl acetate (EVA) foils. Solar cells or other materials that are too thick to laminate in PVB foils can be embedded in this intermediate layer. Soundproofing glass panes are generally made of laminated glass because the casting resin’s composition can be adapted to special frequency ranges. Casting resin is available as a single or multiple-component material that hardens under UV light. In contrast to laminated safety glass, ordinary laminated glass does not usually meet any formal safety requirements. Replacing one or more layers of laminated glass with sheets of transparent polymethyl methacrylate (PMMA) can, for example, reduce the weight of break-in-resistant or bullet-resistant special safety glass by up to 50 % while also improving its soundproofing (Fig. B 2.34 h 19, p. 99). Another application for laminated glass is in designs that use holographic-optical elements (HOE). To make images look threedimensional, thin film foils that filter different light wavelengths are embedded between panes of glass. They bend the colours of light in a certain wavelength range, making them visible. Outside this wavelength range, the HOE is as clear as glass. The laminated glass protects the expensive foils from the weather. By overlapping several holograms, light can be deflected in various directions regardless of its angle of incidence. This makes it possible to deflect diffuse light deep into interiors and thus increase the amount of daylight inside. Coatings

Coatings used as functional or design layers improve a pane of glass’s qualities, but they may need protection from exterior influences, which must be taken into account in making compound or multi-pane insulating glass. Countless possible coatings are continually

Production of single-pane toughened safety glass and annealed glass B 2.6 Comparison of the properties of toughened safety glass and annealed glass B 2.7 Distribution of stresses in chemically strengthened glass compared with thermally strengthened glass B 2.8 Structure of laminated safety glass B 2.9 Laminated glass with a laminated metal-coated fine-meshed textile. Verwaltungs- und Ausbildungszentrum, Rorschach (CH) 2013, Gigon / Guyer Architekten B 2.10 Division of coatings into classes

adapted to various requirements depending on demand. The way layers in such panes are structured varies from manufacturer to manufacturer. There are two main coating processes: • During glass manufacture (“online”, hard coating) • On basic glass after its manufacture (“offline”, soft coating) Depending on their type, structure and composition, coatings can be applied on the outside or inside of panes or in the space between the panes. DIN EN 1096-2 divides them into classes for different applications in accordance with the required robustness of the layer (Fig. B 2.10). Gas filling between the panes provides a special atmosphere that protects against corrosion and safeguards them from mechanical loads throughout the entire treatment process, so more sensitive coating systems can be applied here than on the unprotected exterior sides. Coatings on the sides of panes exposed to weather, e.g. with Low-E functions, have especially comprehensive requirements. Coatings on the outside of highly insulating triple glazing can prevent panes from freezing (because on winter nights the panes lose less energy to the cold clear night sky through radiation and do not cool as much). Links between functional coatings, heat transfer and solar energy (including thermal insulation and solar protection glazing) are explained in detail in the chapter on “Passive solar energy use” (p. 170ff.). Some types of coating can be applied before curved, thermally toughened or annealed glass (toughened and tempered glass) is heat-treated, but they must be able to withstand the tempering process’s high temperatures of 630 to 720 °C. Pyrolytic coating (hard coating) Hard coating involves the application of a metal oxide to the still very hot glass surface during the manufacture of float glass. The oxide bonds strongly with the glass due to a pyrolytic reaction. Panes of glass coated in this way reflect sun better, improving solar protection. The emissions-reducing coating also has an insulating effect. They have an emissivity of about 13 % compared with 92 % for a normal glass surface. Panes coated in

this way are relatively robust so they can be installed as single panes without any problems, and their thermal insulating effect is similar to that of insulating glass with a U value of 1.8 W/m2 (12 mm between the panes and 95 % argon filling). If, however, the coating is exposed, soiled or covered with condensate, its emissivity increases greatly, i.e. its effective U value is reduced accordingly. The surface durability of these coatings is close to that of an untreated glass surface. [2] Cathode sputtering (soft coating) After being cut to size, a cathode sputtering process (magnetron sputtering or a soft coating process; Fig. B 2.11) is used to coat glass with various elements and compounds (e.g. metal oxides). This physical process, which is carried out in a high vacuum, involves firing energy-rich ion particles out of a cathode from a ‘target’ (the substance being deposited, e.g. silver) onto a target surface ("sputtered" on). The glass passes through an inline coating unit, which continuously covers it on one side with a usually complex multiple layer of bonded, functional, protective and coating layers (Fig. B 2.12). Depending on the type of material applied, the coatings are more or less durable and stable in the long term. They are not as durable as float glass surfaces or hard coatings, so this kind of coated glass must be processed promptly. The coated side of insulating panes must be in the space between the panes to prevent corrosion or mechanical damage. During the prescribed storage period, coatings can be cleaned in special washing units without damage. Sol-gel process A sol-gel process is a chemical coating process in which hot glass is submersed in a bath of metallic compounds. The compounds adhere to the glass surface and are pyrolised (using heat) and converted into the relevant oxides. Solar protection glass and glass with low reflection levels can be made in this way. Anti-reflective coatings Anti-reflective coatings improve effective transmission by reducing the reflectiveness of glass surfaces, i.e. visibility through them is enhanced, especially when the glass is

Class A

The coating is on the side directly exposed to the weather.

Class B

The coating is on the exterior glass surface facing directly away and should be protected from the immediate impact of weather influences. The coated glass can be installed as a single pane.

Class C

The coating is only applied in the space between the panes in an insulating glazing unit. The glass must be transported in special packaging and can only be worked immediately before further processing.

Class D

The coated glass is only applied in the space between the panes and must be made into an insulating glass unit immediately after manufacture. It cannot be installed as a single pane of glass.

Class S

The coated surface can be applied inside and out and is suitable for special applications, e.g. for display windows.

B 2.5

B 2.10

89

Reflection [%]

Materials, components, types of construction

Covering layer

Intermediate layer

Silver layer Intermediate layer Protective layer

ε=1-R

Silver layer

B 2.11

exposed to high levels of direct sunlight. Such coatings also increase energy transmission (g value) by up to 5 % compared with uncoated glass. Coating systems with very low angle dependence increase transmission, especially when the sun is low in the sky. Such coatings offer visibility with less reflection from the outside (e.g. for display windows) as well as from the inside to the outside in unfavourable conditions (light inside, dark outside, especially desirable for conservatories). Typical reflectivity of about 4 % for a pane’s surface can be reduced to about 0.3%. Anti-reflection-coated glass coverings also increase yields from solar panels. Self-cleaning glass Glass with a specially treated surface that rarely needs cleaning is called self-cleaning. Titanium dioxide coatings just a few nanometres thick have been used for this purpose since 2000. They are applied in a sputter process that completely retains glass’s optical qualities, in particular its transparency. The titanium-dioxide coating has two main functions: firstly, the coating’s high surface tension means that it is hydrophilic, so an even film forms on it when it rains. Water runs off it evenly and no drops and residues from drying water form on it. Glass surfaces treated in this way do not need to be cleaned as often, which reduces operating costs, especially for surfaces that are hard to reach. Secondly, the surfaces are photocatalytic, i.e., UV radiation (sunlight) oxidises deposits of organic dirt from the surrounding air. This catalytic

B 2.11 B 2.12 B 2.13

B 2.14

B 2.15

90

Magnetron coating plant Structure of a magnetron coating (Low-E, sun protection or multi-functional layer) Reflectivity of thick opaque layers of aluminium (Al), silver (Ag) and gold (Au) in perpendicular incident light A microstructure coating on glass made of a precisely perforated stainless steel foil less than 0.2 mm thick. Developments ranging from the single glass pane to multi-pane insulating glass (MIG)

Sun protection

Protective layer

Multifunctional layer

Silver layer

Low-E

System based on electrical conductivity and interference

Protective layer

100 Visible light Aluminium Silver Gold

80

60

40

20

Adhesive layer

0 200 nm

Glass

500 nm

1 µm

B 2.12

effect is permanent. Titanium-dioxide coatings are delicate and must be carefully protected during transport and installation to avoid scratches. It should also be ensured that panes are installed the right way round (with the coating on the outside) and that the surface does not come into contact with silicone during installation. Coatings with the same active principle are now available on other types of materials, e.g. on PVC/PES membrane materials or PTFE /glass fibres. Since there is not enough UV radiation for the photocatalytic process in interiors, titanium-dioxide coatings do not work there, but hydrophobic coatings based on fluorinated silane can be used instead. They increase normal drop formation by reducing surface tension and cause water to run off the surface. This socalled lotus effect makes interior surfaces easier to clean. Mirror and reflective layers Mirror or reflective layers, coatings with a high level of direct reflectiveness in the spectral range of visible light that reflect objects precisely, are functional in that they screen out the sun. They can also be used in decorative designs. Mirror coatings, which were developed for use inside, do not usually offer any appreciable transmission. They are mostly special silver coatings that can withstand temperatures up to about 80 °C and normal humidity in rooms but should not come into direct contact with water. Mirror coatings are available in various colours, including clear, green, grey, black and bronze. In the space between multiple panes, where they are protected from corrosion, thin silver coatings can be used to create a reflective surface, although their reflection is not complete, but depending on the coating’s thickness and quality, they retain a certain residual transmission and absorption. These are referred to as semi-transparent or partially transmitting mirror coatings. The degree of reflectivity in areas can be adjusted while largely retaining the neutral colours of the layer in transmission and reflection across wider areas. Neutral coatings as well as coloured versions are available.

2 µm 5 µm Wavelength [%] B 2.13

Designer coatings Designer coatings, such as those based on chrome, are used mainly in decorative designs. They are suitable for inside and out, but they are usually applied to pane surfaces that are not exposed to weather so as to maintain their brilliance for long periods. The process also makes it possible to coat only certain areas by first applying masking, so patterns, fine lines, lettering and the like can be created. Transitions between coated and uncoated surfaces make it possible to create complex, high contrast motifs. Designer coatings can also be combined with other coating systems (e.g. solar protection coatings). They can reflect over 50 % of light, although the coated surface’s transmission rate is usually very low (< 9 %). They are much more robust than conventional silver mirrors. Materials other than glass, including many plastics (as sheets, foils or special grid structures etc.), can be coated with design coatings or mirror surfaces. Enamelling and printing In the enamelling process, a coloured ceramic coating sprayed onto glass or a screen or digital print is burnt into the surface of thermally toughened or partly toughened glass during the manufacturing process. Enamel coatings can be slightly translucent, depending on their thickness. Screen-printing involves printing colour directly onto the glass surface through a finely woven textile, enabling areas of colour and images to be printed very precisely. In contrast to ordinary screen-printing, digital printing can print several colours at the same time. Microstructured coatings on glass

As well as homogeneous coatings, microstructured functional coatings can also be applied to glass. Metal foil positioned on the exterior pane of insulating glass in the space between the panes is perforated at a precisely defined angle, creating a microscopically fine strip structure (Fig. B 2.14). The transmissibility to radiation of these microstrips varies depending on the angle of incidence. The coating behaves geometrically like a rigid sunscreen system, but the fine strip structure

Materials, components, types of construction

Solar radiation with a high angle of incidence

Micro-louvre foil

Energy input 10%

Reflected solar radiation

Solar radiation with a low angle of incidence Energy input 33% Reflected solar radiation Thermal insulating coating B 2.14

Matt and frosted surfaces

Glass surfaces can be rendered matt by the application of acids or mechanically by sandblasting them. How matt the glass surface is can be controlled in the etching process by varying the length of time that the glass is exposed to the acids. The further away an object behind matt glass is, the more its contours are blurred when you look at them through the glass because the light is diffusely dispersed. Patterns and images can be etched into a glass surface by covering areas of it with stencils. The rougher the glass is, the more sensitive it is to water or fat-based soiling (e.g. fingerprints), so matt surfaces should be installed in protected positions. Usually, only one surface can be treated in this way, so the untreated side can be oriented towards users. Depending on their manufacture, etched panes can also be further treated, e.g. curved or thermally toughened. Multi-pane insulating glazing

Single-glazed elements that close openings have a Ug value of about 5.8 W/m2K and offer almost no thermal insulation, so efforts have been made for a long time to increase the insu-

lating effect of glazing. Fig. B 2.15 shows the main steps in these developments so far, which are described in more detail in the chapter on “Working with historic windows in existing buildings and architectural monuments” (p. 148ff.). The most important optimising measures are based on the thermal insulating effect of stationary air between two panes of glass. Almost 100 years ago, this had already halved heat transfer through glass. It was initially impossible to seal the bonding edges of panes so that no moisture or dust could permeate, which resulted in condensate regularly accumulating in the space between the panes. The following improvements have been gradually introduced: • Creation of a permanently gas-proof edge bond • Integration of desiccants into spacers to absorb any residual moisture in the space between panes and any damp permeating from outside • Application of transparent functional layers to panes’ inner surfaces to reduce radiant heat transfer (Fig. B 1.13, p. 54) • Replacement of air filling with special heavy gases (noble gases) with reduced thermal conductivity U value [W/m2K]

means that you can still see through them. Integrating such microstructured layers into insulating glass can be less expensive than external sunscreens. Their protected position in the space between the panes means that they do not have to be maintained and repaired and, in contrast to ordinary systems, can function even in strong wind conditions. They are also not exposed to corrosion, soiling or the wear and tear caused by weather. The sunscreen effect of microstructured coatings changes with the sun’s movement during the day and the time of year, so it varies depending on the coating’s location. The higher the sun, the lower the coating’s total energy transmissibility (g value). Systems with high angles of incidence have a typical g value of just 14 % (double glazing) or 10 % (triple glazing) in summer, while in winter, the g value can be up to 30 or 25 %, respectively. Solar radiation will effectively warm the room in winter.

• Minimising heat transfer in and around spacers • Increasing the number of panes from two to up to five (with the significant disadvantage of heavier weight) and replacement of middle panes with coated plastic foils • Use of additional transparent functional coatings to further improve the thermal insulation of the surface of the pane in the room and/or the side exposed to the weather on the outside (improved visibility /no freezing in winter) • Minimising the share of thermal conductivity in overall heat transfer by evacuating the air in the space between the panes (see “Vacuum glazing”, p. 94) As well as the edge bonds of multi-pane insulating glass, the frames that hold glazing have also been constantly further developed, for window frames as well as facade systems. If they are carefully manufactured, e.g. with a sealant-free rebate and sufficient vapour pressure equalisation to prevent long-term damp and without additional mechanical loads on their bonded edges, current multipane insulating glass units have a service life of 30 years and more.

Single panes of glass 6 in wooden frames

5

4

"Panzerfenster" (double glazing) 1900 CUDO 1934

Gado 1954

Thermopane 1938

3

2

1

Bonded double layers 1970 Inert gas fillings 1970

Multi-pane 1950

Triple glazing ~1970 Functional Warm coatings edge ~1980 1995

Vacuum Quadruple insulating glazing glazing 2011 2004

0 Year of market launch B 2.15

91

Materials, components, types of construction

• Reduces heat transfer through the edge bond (Ψ value; see “Special heat transfer coefficients in and around building openings”, p. 54f.)

Outside Sun protective coating Pane of glass Space between the panes (air or gas filled) Spacer Diffusion opening Butyl sealing Desiccant Polysulphide sealing B 2.16 B 2.16 B 2.17 B 2.18

Structure of a pane of insulating glass Comparison of various spacer systems Comparison of a conventional aluminium spacer and a typical warm-edge solution (here TPS system) B 2.19 Ug value for types of glazing according to DIN EN 673 with 90 % gas filling B 2.20 Various ways of building noise-insulating glazing

The surfaces of multi-pane insulating glass units are numbered from the outside to inside and the following descriptions are common in the industry: “8(12)4(12)4” equals “glass (space between panes) glass (space between panes) glass”. Colons or other symbols in these abbreviated descriptions indicate coatings on panes. “8:(12)4(12)4:” for example, means coatings on position 2, so on the inside of a 8 mm thick exterior pane, and on position 6, so the side facing the interior of a 4 mm thick interior pane in a tripleglazed window. Spacers and edge bonds, “warm edge” Today’s insulating glass consists of at least two and often three single panes bonded at the edge by a spacer solution. The edge bond fulfils the following tasks: • Durable sealing of the space between the panes (gas-proof, moisture-resistant) • Absorbs various degrees of thermal expansion in the joined panes • Absorbs movement and mechanical loads • Absorbs loads from insulating glass itself (see “Particular loads on insulating glazing”, p. 73ff. and Fig. B 1.56, p. 74)

Most insulating glass units have a double sealing system. The first seal sits between the spacer and each pane. Another seal is mounted outside in front of the spacer and between individual panes. It serves as the second seal and bonds the panes together (Fig. B 2.16). A silica gel or zeolite desiccant is integrated into the spacer and absorbs any moisture in the space between the panes, which is sealed on the outside. This lowers the dew point of the enclosed gas filling to below -30 °C. The quantity of the desiccant is specially measured to absorb slowly diffusing moisture from outside and increase the service life of multi-pane insulating glass units. If moisture collects in the space between the panes, it condenses when it cools below the dew point, so the glass fogs up and becomes irreversibly “cloudy”. The high vapour pressure gradient between the space between the panes of multi-pane insulating glass units and the air outside them imposes very high demands on the manufacture of these units. Edge bonds must be protected from solar radiation unless they are made of silicone. Enamelling or coating can provide the necessary UV protection for sealing systems of panes that do not lie or stand in a glazing rebate (see “Stepped insulating glass”, p. 93). Fig. B 2.17 compares different spacer systems, which can vary greatly in terms of their effective thermal insulation. Current systems can also be compared based on their measured equivalent heat conductivity. [3] Thermally optimised systems (“warm edges”) have effective thermal insulation in the critical transition area between the glass and frame, and their higher surface temperatures mean that condensate rarely collects there. The optimised spacers improve a window’s Uw value by about 0.1 W/m2K. Insulating glass units with warm edges are now the main type manufactured in Germany. The thermal conductivity of the edge bond

is, however, not the only criterion of interest in choosing a system. Economic factors connected with the manufacturing process (e.g. cost, speed of manufacturing) and whether the spacer and edge bond can be used in the construction of curved edges may also be important. This is not possible with all units. Architects will also be interested in how an edge bond appears visually. While conventional aluminium or stainless steel spacers in the space between the panes reflect light, thermally optimised spacers are usually black (Fig. B 2.18), so they are less visible in window frames because less light reflects off them, especially at night. Corners and splices where curves or 45° angles may be required demand particular attention from designers (e.g. positioning and installing the TPS (Thermo Plastic Spacer) system). Gas filling in the space between panes The effective insulation of multi-pane insulating glass units can be increased by using special heavy gases instead of pre-dried air in the space between the panes. These gases, including noble gases such as argon and krypton (more rarely xenon), are much less conductive than air (see “Thermal conduction”, p. 51; Figs. B 1.8, p. 53 and B 1.12, p. 54). DIN EN 1279 assumes that the Ug value of insulating glass units will increase by no more than 0.1 W/m2K and that the gas filling will be reduced by 90 to 85 % over their service life. Initial filling levels of ≥ 90 % are common now and form the basis for calculations in the relevant tables. In Germany, over 90 % of insulating glass units are currently filled with argon, which costs about the same as the alternative – pre-dried air. Krypton is about 30 % more expensive by volume, so it costs about 20 % more for a 1 m2 unit (16 mm space between the panes) [4] and is therefore more rarely used unless there are compelling structural reasons for a slender window structure with little space between the panes. The goal should be to choose the distance between the panes depending on the type of gas so that the gas conductivity is as low as possible (large space between the panes), while trying to

Principle 5 3 1 2

5 3 4

11

10 5 6

8 4

13 5 4 6

7 12 4

9 2

Double sealed metal

Stainless steel

Aluminium, thermally separated

Polypropylene, metal

Polyisobutylene

Silicon foam

Composite plastic, metal foil

Example

Ordinary aluminium spacer

Chromatech plus Nirotech GTS WEP-classic

Azon Warm Light

TGI Spacer

Ködispace Thermo Plastic Spacer

Super Spacer ACSplus

Swisspacer V Thermix TX.N plus Chromatech Ultra

Ψ value [W/mK]

0.080 – 0.120

0.0486 – 0.068

0.046 – 0.058

0.038 – 0.049

0.034 – 0.043

0.032 – 0.041

0.030 – 0.050

1 2 3

Primary sealing Secondary sealing Spacer (metal)

4 5 6

Sealing Desiccant Metal strips

7 8

Silicon foam Polyurethane, hard

9 10 11

Polyisobutylene Polyisopropylene Aluminium profile

12 13

Metalised foil Composite plastic B 2.17

92

Materials, components, types of construction

avoid too much heat convection in the space between the panes, which can occur if panes are too far apart. The heaviest possible gas can be advantageous here. Predried air is the only filling suitable for edge systems bonded with silicon because gases like argon and krypton can escape through the silicon. In selecting the space between the panes, the so-called "insulating glass effect" must also be taken into account. It is caused by variations in pressure in the enclosed gas volume and is more pronounced where panes are far apart (see “Particular loads on insulating glazing”, p. 73f.). Sound-insulating glazing The structure of multi-pane insulating glass units can be optimised to improve sound insulation. An insulating glass unit consisting of two or three single panes of the same thickness separated by a space behaves like an oscillating mass-spring-mass system with its own resonant frequency, resulting in a soundinsulating effect. This effect is, however, fairly slight for certain frequencies (see “Sound insulation”, p. 66ff.). Combinations of glass of varying thicknesses (Fig. B 2.20 a) and of float and laminated and laminated safety glass (Fig. B 2.20 b) can improve the estimated sound reduction index Rw value depending on the joining of individual panes and casting resin or foil used. It is essential that a window consisting of two single panes does not behave like a single pane of the same overall thickness but like two panes separated by a layer, so the bond between them must be as soft as possible. Sulphur hexafluoride (SF6) gas was once used to improve sound insulation but is now no longer used in Europe for environmental reasons. Reducing the weight of insulating glass units with more than two panes The disadvantage of modern triple insulating glass units is that the extra pane of glass makes them very heavy (the effect is even worse in quadruple glazing). ift Rosenheim has investigated ways of reducing their weight by using thin glass (2 – 3 mm) and plastic

sheeting and foils in a research project. Their results show that panes of glass less than 4 mm thick and with a short edge (from about 65 cm) need to be toughened for structural statical reasons but that this is not absolutely necessary for larger windows. Thin panes of insulating glass do not provide as effective insulation against airborne sound as panes of conventional thickness do. This can be compensated for by giving insulating panes an asymmetrical structure (see “Soundproof windows”, p. 69). Thin panes are comparable with ordinary insulating panes in terms of their heat transfer coefficient, total energy transmittance and luminous transmittance. Windows with foils instead of glass as the middle pane have proven to be complex but feasible systems (Fig. B 2.34 b, p. 99). A transparent plastic sheet as a middle pane requires a special mounting to absorb thermal expansion without imposing loads on the edge bond. The moisture content of plastic sheeting means that it must either be dried before installation or more desiccant be used. No such solutions are available on the market yet. Sash bars Current glazing units have developed over time from relatively small formats that were combined to cover larger areas. Small-format window glazing is often characteristic of historic buildings. Various kinds of sash bars have evolved to help retain this appearance with current glazing technologies, especially for multi-pane insulating window units: • Fixed sash bars • Single or multiple crossed sash bars in multi-pane insulating glass units • Sash bars that divide areas of glazing Fig. B 2.21 shows the different types of sash bars and relevant standard reductions for Uw and Ug values. Stepped insulating glass Stepped insulating glass (Fig. B 2.22) is used in building envelopes in structural glazing systems or in all-glass opening sashes where the insulating glass and opening sash have a

Air filling: Ug = 1.4 W/m2K Space between the panes 16 mm

Argon filling: Ug = 1.1 W/m2K Space between the panes 16 mm

load-bearing adhesive bond (all-glass sash, Fig. B 2.66, p. 112). The sash profile is set behind the step and adhesive bond, and an upper or exterior pane projects over a lower or interior pane so that water can run off it unimpeded. The upper or outer pane cannot be allowed to rest on or support the insulating glass. UV-resistant silicon, a screen print or metal sheet must protect the exposed edge bond from UV radiation and moisture. Alarm glass Glass can be equipped with sensors to improve structural protection against breakins. Such panes usually have an electric circuit path on the inside corner of a (toughened) exterior pane of insulating glass (Fig. B 2.23). The circuit is connected to an alarm that goes off when contact is broken by the breaking of the pane and the circuit. Heating glass Heating glass, which has long been used in car windscreens, is usually provided for windows as a laminated glass unit made of two toughened or annealed glass panes, with a heat-generating transparent coating between them and an electrical connection at one edge (Fig. B 2.24). The heating layer is a transparent metal-oxide coating that is vapourdeposited or sputtered on. Various panes of glass can be combined and made into insulating glass units with the heating glass on the interior side. Each pane requires its own temperature control to regulate the required temperature and to ensure that a maximum permissible pane temperature of 60 °C is not exceeded. Typical area outputs range from 100 – 800 W/m2. A thermostat can also help regulate room temperature. These kinds of technical glazing units have a wide range of potential applications in: • Thawing snow loads on glass roofs, • Defrosting iced-over panes, and • Eliminating condensation from misted panes. Standard products are available in square forms of 200 ≈ 300 mm (toughened glass 8.2 up to approx. 10 mm) up to 1,500 ≈ 3,000 mm (toughened glass 12.2 up to approx. 14 mm).

Krypton filling: Ug = 1.0 W/m2K Space between the panes 10 mm

a Argon filling: Ug = 0.7 W/m2K Space between the panes 12 mm B 2.18

Argon filling: Ug = 0.6 W/m2K Space between the panes 16 mm

Argon / Krypton filling: Ug = 0.5 W/m2K Space between the panes 14 mm B 2.19

b

Left: outside / right: inside a Asymmetric pane structure b Combination of float glass and laminated safety glass B 2.20

93

Materials, components, types of construction

Type

Fixed sash bar(s)

Single sash bars in a multipane insulating glass unit

Multiple sash bars in a multipane insulating glass unit

Window sash bars

0.0

0.1

0.2

0.4

+ 0.1

+ 0.1

+ 0.2

Example

Detail

ΔUw [W/m²K] Correction value ΔUg [W/m²K]

B 2.21

1 2

4

7

1 2

6

3 5 6

1 3 4

4 5 1 2 3 4 5 6

Top pane Bottom pane, e.g. laminated safety glass Edge bond Exposed part of the edge bond Drip edge Cover or screen print

1 2

Vacuum glazing

Vacuum insulating glazing (Fig. B 2.25) uses a different thermal insulation strategy than that of conventional gas or air-filled multipane insulating glass, minimising gas thermal conductivity and completely preventing convective heat transfer in the space between the panes by removing gas molecules (evacuation). This type of glazing was developed in Japan to replace single-pane windows in historic wooden-framed windows. Units consisting of just 2 ≈ 3 mm of toughened glass 0.2 mm apart (6.2 mm in total) and low weight can achieve a Ug value of about 1.3 W/m2K compared with the 5.8 W/m2K of single-pane glazing. The vacuum in the space between the panes means that both panes are exposed to atmospheric pressure of about 10 t/m2. A 20 to 40 mm grid of punctiform spacers, which are mainly involved in heat transfer, must therefore maintain the space between the panes (Fig. B 2.25 c). Spacers with a diameter of typically 0.5 mm are clearly visible up to a viewing distance of about 1 m (Fig. B 2.25 b). The edge bond must permanently withstand the extreme negative pressure in the space between the panes (typically by using welded metal or glass soldering) while being exposed to high mechanical loads from the fluctuating thermal expansion of panes, for example. The edge bond is a significant thermal weak

4 5 6 7

Alarm loop Toughened safety glass outside

B 2.22

94

1 2 3

2

B 2.23

point. Current research projects into vacuum insulating glazing are attempting to achieve Ug values under 0.5 W/m2K in units of 6 to 10 mm thick, with prices in the same range as conventional triple glazing. Research efforts are focused on creating durable edge bonds that allow for the current low-E coatings, optimised spacers and the technology required to manufacture them. Fig. B 2.26 a shows an approach towards further significant improvements using a modified edge bond and a special thin glass equipped with optimised spacers on both sides. This high-performance vacuum insulating glazing has achieved Ug values up to 0.25 W/m2K in laboratory testing on prototypes (Fig. B 2.26 b). Their usually symmetrical pane structure and connecting spacers, which neutralise the mass-spring-mass effect, mean that both types of vacuum insulating glazing offer only low levels of sound insulation. [5]

B 2.24

involved being able to control light and energy input through transparent glazing. The appeal of such systems is that they allow users to react appropriately in every season of the year. Energy input is desirable in winter, so the goal then is high levels of total energy transmittance (g value). In summer, however, incoming solar radiation must be minimised, so a low g-value is preferable. The dynamic selectivity (S*) used to characterise dynamic behaviour results from the relationship between maximum transparency TL and a minimum g value: S* = TL,max /gmin. B 2.21 B 2.22 B 2.23 B 2.24 B 2.25

Panes with variable light and total energy transmittance

Exterior walls that can be used to operate and manage all essential functions, such as regulating light and energy input, visibility and thermal insulation as well as providing energy in the form of heat and electricity, while being as slender as possible are an ideal for many planners. In the early 1980s, Mike Davis coined the term “polyvalent wall”. His vision largely

Outer pane Infra-red-reflective coating Space between the panes with gas filling and circumferential sealing Spacer with desiccant Heat-generating layer in the composite Inner pane Conductive strips for electrical connection

B 2.26

Sash bars in accordance with DIN EN 14 351-1 Appendix J and DIN 4108-4, Table 10 Typical structure of staged insulating glass Pane of glass with alarm loop attached Structure of heatable insulating glass Vacuum glazing a Structure b The punctiform spacers in vacuum glazing (“pillars”) are only visible at very close distances, so they barely impede the view through the window. c Thermal bridge effect in and around spacers and at the edge bond of vacuum glazing. This requires panes to be set in deeper at the edge and a well-insulated frame. High-performance vacuum insulating glass (HP-VIG) a Structure and edge sealing b Comparison with standard vacuum insulating glass depending on the low-E coatings applied

Materials, components, types of construction

Glass pane 3 – 4 mm (float or toughened safety glass) Possibly low-E coating at position 3 (and /or 2) Space between the panes 0.2 –1 mm Gas pressure < 10-3 mbar Punctiform spacers Ø 0.5 mm, grid 20 – 40 mm, slightly reflective, e.g. made of stainless steel or ceramics

290.0 290.5

291.0 291.5 292.0

292.5

Temperature (warm) [K] Gas-tight edge bond (e.g. glass / metal, welded) b

Total thickness ~10 mm Low-E coated float glass

U value [W/m2K]

a

c Standard triple insulating glazing with argon filling 0.7 0.6 Simulation standard VIG (metal spacer)

0.5

Thin glass

B 2.25

0.8

0.4 Spacer 0.3

Vacuum (< 10-4 mbar)

0.2

Edge sealing area

Simulation HP-VIG (metal spacer) Verification for HP-VIG concept (Measurements of real test specimens)

0.1

With glass solder

0 0

Flexible connection

0.01

0.02

0.03

a

b

Solutions that offer switchable g values and high dynamic selectivity may also be of interest, although if these two criteria are not entirely met, the cost and effort involved in such solutions must be examined. A range of glasses that offer variable degrees of light and energy transmissibility and through which visibility can be controlled are now available (but not all on the market yet). Based on further criteria, it can be generally divided into: • Colourless, simply diffusing functional glass (e.g. thermotropic glass) and coloured functional glass that does not scatter light (e.g. electrochromic glass) • Passive switching (automatic switching) or active switching solutions • Solutions with just two states or intermediate states Weather conditions, such as temperature (thermal-controlled) or UV radiation (photocontrolled), can serve as automatic control signals. Applied voltage (electric) and gas release in the space between panes are usercontrolled, actively switchable signals. It should be noted that some solutions are not colourless in transmission and reflection, whether they are switched on or not. Some glazed units change state quickly (< 1 second), others more slowly (> 15 minutes) and involve aesthetically unsatisfactory intermediate states (a blotchy, cloudy appearance). Long switching times also

cause user acceptance problems because the effect is produced slowly, and users find it hard to understand the technical reaction involved in the switching process. Fig. B 2.27 provides an overview of various panes with variable light and energy transmittance. Only electrochromic glazing and liquid crystal glass are currently available on an industrial scale. Electrochromic glazing Electrochromic glazing is a sun protective glass with variable total light and energy transmittance (g value; Fig. B 2.29). It consists of a pane of laminated glass covered with a conductive polymer foil that makes use of an electrochromic effect (Electrochromic laminated glass, Fig. B 2.28). A thin, nanostructured tungsten oxide-based coating causes an ion exchange, which makes it change its colour in five stages or become continuously blue when an electric current is applied. This reduces the transmission of sunlight through the glass, especially in the red and near-infrared range of the solar spectrum, while maintaining its transparency. The transition from the lightest to the most intensive setting is fluid and takes about 15 minutes for a 1 ≈ 1 m pane, longer for larger formats. Maximum pane sizes with this technology are currently approximately 1.3 ≈ 3.3 m. The electrical power input required is about 10 W per

0.04

0.05

0.06

0.07 0.08 Emissivity [ε] B 2.26

operation. The switching process alone requires electrical output of about 1.5 W/m2. Electrochromic glazing can be installed in the form of multi-pane insulating glass without any major restrictions, i.e. it can also be used on sloping surfaces and those that can be walked on. It should be installed as dry glazing (see “Connection between glass and frame”, p. 108f.) and silicon must not come into contact with the pane’s edge bond, which must also be protected against UV radiation. [6] Liquid crystal (LC) glass Liquid crystal glass is usually installed as a laminated glass unit consisting of at least two joined toughened or annealed glass panes between which a liquid crystal film is embedded in two layers of a conductive foil with electrical contact on one edge. The use of a thermoplastic bonding agent results in a laminated glass with security features. An integrated power connection enables users to regulate the glass’s transparency with the push of a ballast unit button (response time 2,200 > 1,950 > 1,700 > 1,400 > 1,100 < 1,100

Tropic of Capricorn

kWh/m2a kWh/m2a kWh/m2a kWh/m2a kWh/m2a kWh/m2a

C 1.1

In contrast to active or indirect solar energy use, passive solar energy use (or direct solar energy use) is the direct use of solar radiation for various purposes in a building. Solar energy is harnessed without any other aid than the building envelope, mainly for heating and supplying a building with daylight. The so-called greenhouse effect plays an important role in such systems (see “The greenhouse effect”, p. 173). Optimum use of solar energy, however, does not mean admitting as much solar radiation as possible through building openings into buildings. Instead, the goal is to use solar radiation to directly supply most of a building’s energy needs throughout the year, minimising the need for heating energy in winter and cooling energy requirements in summer (ideally they could be dispensed with altogether) and artificial lighting all year round. Appropriate measures should also result in minimised cooling costs. Over the course of a year, the relevant conditions change dynamically (fluctuations in usage, outdoor climatic conditions, solar radiation etc.), making adaptive solutions especially suitable for optimum passive solar energy use. Inflexible systems, in contrast, are always compromise solutions. Depending on the characteristics of the building envelope and season, efficient sunscreens can play a crucial role in this context because, of all the individual components of building openings, they have the greatest influence on energy balance and interior comfort, given the current quality of glass usually installed.

Openings decisively influence a building’s energy balance. They are often a cause of heating energy losses through transmittance and an exchange of air through ventilation and leaks, but such losses can be offset by potential benefits, mainly from solar energy gains and from transmitted and ventilation heat in summer. A thorough survey of location and structural conditions is a crucial basis for effectively planning building openings and a prerequisite for optimum passive solar energy use. Other parameters and conditions that must be taken into account and coordinated in planning buildings and building openings are explained below. Here, the focus is on the context of and interaction between openings

C 1.1 C 1.2

C 1.3 C 1.4 C 1.5

C 1.6 C 1.7

Worldwide distribution of annual global solar radiation at the horizontal level Irradiation on surfaces perpendicular to the direction of incident radiation depending on the sky’s cloudiness Diagram of the sun’s course (50° N) Projection diagram showing the sun’s courses Total solar radiation [W/m2] on differently oriented wall surfaces (E, S, W) on sunny days in various seasons in Germany a Summer b Spring/autumn c Winter Irradiation [W/m2d] on south-facing surfaces of different inclinations in Germany Irradiation [W/m2d] on differently oriented vertical surfaces in Germany

Partly cloudy

Sun as a yellow disc

Sun as a white disc

Only sun’s outline visible

Dark and cloudy

1,000 W/m2 1,000 W/m2

500 W/m2

450 W/m2

300 W/m2

200 W/m2

100 W/m2

10 %

30 %

50 %

70 %

100 %

100 %

Cloudiness of the sky

Clear

Solar radiation Ratio of diffuse radiation [%]

Hazy

50 %

C 1.2

170

12 h 11 h

13 h

ne

60

Ju

Solar angle of incidence [°]

Passive solar energy use

ay M

10 h

Ju

ly

50

ril

Au

Ap

9h

7h

t.

18 h

Nov.

5h

19 h

Dec.

10

and factors that affect the building (e.g. its thermal mass and spatial depth) because more than just openings in the envelope needs to be considered in optimising passive solar energy use.

17 h

Oct.

Jan.

6h

16 h

Sep

Feb.

25

15 h

g.

. Mar

8h

14 h

North-east

90

45

0

45

90

East

South-east

South

South-west

West North-west C 1.3

Solar energy – location and structural orientation

S

O

800

W S

600 400 200 0

N

4

10

12

14

16

18 20 Time

16

18 20 Time C 1.5

Winter S

800 E

Power [W/m2]

W

600 400

S

800 600 E

400

W

200

200 4

6

8

10

12

14

16

0

18 20 Time

6

8

10

12

14

c

30 0

4,000

60

5,000

4,000

Hor

5,000

Irradiation [ Wh/m2d]

b

4

izon tal

Power [W/m2]

8

a

C 1.4

0

6

W Spring / Autumn

3,000

3,000

1,000

1,000

W S

2,000

0

J

A S O Summer

N

D J Winter

F

M

A M J Summer C 1.6

0

E/ W NE /N W

90 2,000

N

SE /S

Irradiation [Wh/m2d]

Solar energy’s passive service potential is quite large, even in Germany with “only” 950 –1,150 kWh per year and square metre of horizontal surface and an annual average of 1,400 – 2,000 hours of sunlight (of which about 380 accrue in the heating period from 1 October to 31 April). On other parts of the globe, much larger amounts of energy can be gained, as shown in Figure C 1.1. Solar radiation can produce up to 1,000 W/m2 on horizontal surfaces and up to 800 W/m2 on vertical facades. Even under very overcast skies, surfaces perpendicular to the direction of the sun’s rays can still generate 100 W/m2 (Fig. C 1.2). The following geometric factors must be taken into account in establishing the service potential for concrete construction planning. The sun’s changing course during the year, which determines

E

Power [W/m2]

Summer

For planners and clients, the most effective tool in minimising a building’s primary energy needs is optimising its passive solar energy use, which is usually financially worthwhile in operation. If the preconditions for its use are on offer, solar energy is a (consumptionrelated) free resource. For centuries, buildings worldwide were supplied with more energy in this way than from other energy sources, such as combustible fuels. For most of human history, there was no alternative. This gave rise to site-specific knowledge and appropriately adapted construction styles (orientation, opening sizes, roof overhangs etc.), which only in recent years and especially in industrialised nations have transitionally receded into the background in favour of consuming what once seemed to be unlimited energy resources – fossil fuels such as coal, oil and gas and later also nuclear power.

J

A S O Summer

N

D J F Winter

M

A M J Summer C 1.7

171

Passive solar energy use

[kWh/m2]

Global solar radiation/year (energy)

March / Sept.

June

Dec.

5

4 Direct radiation 3

2 Diffuse radiation 63°

1

40° South

17° South

South

0 J F M Winter

A

M

J J Summer

A

S

O

N D Winter C 1.8

a location’s geographic latitude (Figs. C 1.3 and C 1.4), means that radiation output and energy amounts from variously oriented surfaces will differ greatly (Fig. C 1.5 –1.7). Depending on the season, this results in very different solar energy gains for building openings in south-facing facades, as shown in Figure C 1.9. For some planning decisions, e.g. the geometric design of sun shading or light deflecting systems, the issue of whether focused direct solar radiation that throws shadows or scattered diffuse solar radiation is available can also be an essential one. The respective solar radiation levels can vary greatly depending on weather and location (Figs. C 1.2, p. 170 and C 1.8), which can be very important in choosing locations for active solar systems (see “Active solar energy use”, p. 190ff.).

Solar and thermal radiation – visible light Materials emit electromagnetic radiation with a spectrum specific to their intrinsic temperature (see “Thermal radiation and emissivity”, p. 52). The sun, with a surface temperature of around 5,800 kelvin [K], also emits this radiation with a specific spectral intensity distribution for its very high temperature [1]. From a physical point of view, visible light is electromagnetic radiation in the frequency range perceptible to the human eye, with

is blocked

Solar radiation, short wave (λmax = 0.5 µm)

The material properties of transparent materials: transmission, reflection, absorption

Radiation emission, long wave (λmax = 10 µm)

Heating up C 1.10

172

C 1.9

wavelengths ranging from around 380 to 780 nanometres [nm]. It contains all the spectral colours of daylight, ranging from violet, blue, green, yellow and orange through to red. The sum of individual frequencies in the typical intensity distribution of solar radiation in the visible range is perceived as (neutral) white light. Depending on local conditions and seasonal and daily fluctuations, the atmosphere attenuates or filters some solar radiation on its way to Earth. Rays that reach the Earth’s surface are measured in the solar spectrum (Fig. C 1.12, yellow curve). Their wavelengths range from approximately 300 through to 3,500 nm, so the solar spectrum contains elements beyond the range of visible light, in the short-wave range, which is called ultraviolet (UV), and in the long-wave range, or infrared (IR). Solar near infrared (or solar thermal radiation) should not be confused with long-wave thermal radiation, which is emitted by materials with the usual exterior or interior temperatures of structural elements (at room temperature) and is much less intense. This thermal radiation, also called thermic radiation, is in a much longer wave frequency range (2 – 50 μm, maximum of about 10 μm, 1 μm = 1,000 nm), and so much further from visible light. It is therefore called far infrared (Fig. C 1.12, red curve). Radiation intensity and the energy transported by solar radiation (the area under the yellow curve in Figure C 1.12) are distributed approximately as follows: • Approx. 5 % UV radiation • Approx. 45 % in the visible spectral range • Approx. 50 % IR radiation (solar infrared or solar thermal radiation)

In terms of building physics, transparency means permeability to radiation. Materials can also be permeable to radiation beyond visible light, e.g. thermal radiation. Radiation striking structural elements is transmitted (τ), absorbed (α) or reflected (ρ) in different frequency ranges to varying extents depending on the elements’ material properties, although

in keeping with the principle of the conservation of energy, the sum of the effects per frequency must add up to a 100 % (Figs. C 1.11 and B 1.5, p. 52): τ + α + ρ = 1 (or 100 %) Different radiation-permeable materials vary greatly in their light and heat radiation properties, i.e. their frequency-related transmittance, reflection and absorption capacity. These properties can be influenced by modifying a material’s structure with surface treatments (e.g. nanostructuring) and by various coating technologies. Frequency-specific transmittance or reflection (for optimising selectivity, colour neutrality or emissivity) and angle-dependent reflection (for maximising transmittance, even with oblique incident light) can be adjusted. Figure C 1.13 a (p. 174) shows comparative curves for the solar transmission of materials that are frequently used in and around building openings. The heterogeneous, frequency-dependent transmission or reflection of visible light makes materials, including translucent ones, appear in different colours (ranging from shortwaved violet at 380 nm through blue, green, yellow and orange up to long-wave red at 780 nm) to our eye. Over the course of evolution, the human eye has developed so that it perceives the intensity distribution of solar radiation in the total visible range as neutral, white light. Reflection, transmittance and absorption properties are usually expressed in relation to the visible part of light or the entire solar spectrum, with transmittance as TL (“L” for “light”, also referred to as τvis) or Te (“e” for “energy”, also referred to as τsol). Some other frequency ranges are considered separately, e.g. photosynthetically active radiation (PAR), which is important for plant growth, ultraviolet radiation (UV, e.g. in swimming pools) or near (solar) and far infrared (thermal radiation) for optimising the energy use of building envelopes. Light and thermal radiation’s technical properties depend on angles and can differ greatly in intensity depending on the mater-

Passive solar energy use

Reflection on both boundary layers

Absorption means that a material soaks up electromagnetic radiation energy. This raises its intrinsic temperature and shifts the material’s thermal radiation emissions spectrum, which explains the greenhouse effect. Solar radiation penetrates a structural material permeable to the solar spectrum, such as glass, special plastic plates or foil materials (Fig. C 1.12, green and blue curves), and hits a material that absorbs large amounts of radiation energy (e.g. a floor or the surface of furniture in an

Diffuse transmittance

Refraction

Birefringence

Absorption, long-wave radiation emission and convection C 1.11

1,800 1,600 1,400 1,200

100

UV

In optimising passive solar energy use, it is essential to carefully and responsibly manage this phenomenon, which is used for structures such as greenhouses and thermal solar collectors. Total energy transmittance coefficient (g value)

Supplementing considerations of the transmission of radiation energy, the total energy transmittance coefficient (g value) as specified in DIN EN 410 (for glazing) or DIN EN 13 363-1 and 13 363-2 (for combinations of glazing and solar protection devices) takes other transport routes of energy through transparent structural elements into account. These include absorption (see “Thermal radiation and emissivity”, p. 52), which results in a release of heat through long-wave radiation and convection, and secondary heat transport and secondary heat release on the inside qi. All a building opening’s layers and shells are included in determining the g value (Solar Heat Gain Coefficient – SHGC), especially,

Solar radiation (short wave) Thermal radiation (long wave)

Radiation

Spectral transmittance [%]

The greenhouse effect

Direct transmittance

interior). The material heats up and emits thermal radiation itself, and due to the thermal storage mass and its inertia, a time offset occurs (see “Size and layout of openings”, p. 182). Because the temperature is much lower than that of the sun (30 °C compared with over 5,000 °C), maximum radiation is at wavelengths ranging from 5 and 50 μm, with a typical maximum of about 10 μm, so well beyond the visible range in far infrared. The red curve in Figure C 1.12 illustrates this emissions spectrum. The thermal radiation of heated surfaces can usually not leave the room through the transparent material, because it is not permeable to the long-wave far infrared spectrum (Fig. C 1.12, green and blue curve), but typically exhibits an absorbent (or rarely reflecting) effect. This is true of glass and all standard transparent plastics, which is why solar radiation heats spaces with these kinds of enclosing surfaces (Fig. C 1.10).

Solar radiation [W/m2µm]

ial involved. Direct and diffuse light and differing refraction behaviour depending on the characteristics of materials and surfaces also play a role in reflection and transmittance (Fig. C 1.11) and must be taken into account in creating design effects and correctly estimating solar gains (e.g. for solar radiation with an acute angle of incidence). Multilayered transparent materials (e.g. in multi-pane insulating glass units) also affect total transmittance values because of the multiple reflection effects between individual layers. The properties of reflection, transmission and absorption are more or less present in all transparent materials (with the exception of birefringence, Fig. C 1.11) and influence the total energy transmittance coefficient (g value), so modifying these properties can actively change a building opening’s g value.

Diffuse reflection

Visible

Transmittance

Infrared (IR)

35

90 30

80 25

70 60

20

1,000 Daily average solar radiation intensity and proportion of diffuse and direct radiation in central Germany (50° NB) C 1.9 Midday solar energy input through a southfacing building opening at different angles of incidence and in various seasons C 1.10 The greenhouse effect is mainly a result of the various technical reactions of certain materials to radiation, e.g. glass, transparent plastic panels or foils. C 1.11 Interaction between (visible) radiation, light and transparent materials C 1.12 Links between solar radiation, transmittance, absorption and long-wave radiation emission (greenhouse effect)

Float glass ETFE foil

50

C 1.8

800

15

40 600 30 400

10

20

Thermal radiation (Planck constant) at 300 K [W/m2µm]

Direct reflection

5

200

10 0 0.10 0.38

1 0.78

10

100 Wave length [µm] C 1.12

173

1.0

UV

Visible

Infrared (IR)

0.9 0.8

1,800

0.7

1,600

0.6

1,400 1,200

0.5

1,000

0.4

800 0.3

600

0.2

400

0.1

200

Solar radiation [ W/m2 µm]

Spectral transmittance (solar range)

Passive solar energy use

0 0.25

0.5

Glass, single: Float glass, standard 3 mm (single pane)

Spectral transmittance or reflectivity (solar range)

a Thermal insulating glazing 1.0 Visible UV

1.5

2

Insulating glass with combination coating (structure – 6/16/4): Neutral 61/32 Neutral 51/26 Neutral 41/21

2.5 Wave length [µm]

Plastic foil: ETFE foil, clear 200 µm Plastic panel: PC six-ply multi-skin sheet 16 mm Textile: PVC / PES

Infrared (IR)

0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0.5

1

1.5

b

2

2.5 Wave length [µm]

4 mm float glass + 4 mm float glass, coated (Soft-coating thermal insulation): Transmittance Reflection from outside to inside Reflection from inside to out

Idealised demands on Thermal insulating glazing Transmittance Reflection

Solar protection glazing 1.0 Visible UV

Infrared (IR)

0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0.25

0.5

1

Idealised demands on solar protection glazing Transmittance Reflection c

174

• The individual panes of insulating glazing units, including functional coatings • Interior and exterior sun and glare screen systems in their respective positions • Elements in the space between the panes The g value is influenced by • More absorbent panes of glass, especially through-dyed panes of float glass • Glass thickness • Types and positions of coatings • Surface treatments, such as screen printing with specific degrees of printing

0.9

0.25

Spectral transmittance or reflectivity (solar range)

1

1.5

2

2.5 Wave length [µm]

4 mm float glass coated + 4 mm float glass (soft-coating sun protection): Transmittance Reflection from outside to inside Reflection from inside to out C 1.13

Calculating the g value is complex because the amounts of energy transported through radiation exchange depend heavily on material temperatures. The g value takes into account the proportion of solar radiation in the wavelength range of 300 – 2,500 nm transmitted to an interior, i.e. transmitted solar radiation plus all the heat released by a structural envelope element through secondary heat transport to an interior. Current insulating glazing units usually have g values ranging from 50 to 70 % (Fig. C 1.14). The g value of structural elements or entire building envelopes is measured by a calorimetric testing equipment in a laboratory. In practice, discrepancies of over 10 % can occur between measurements and calculations. Since calculations are usually based on spectral values that apply only to radiation hitting a surface from a vertical angle (others are not usually available), their resulting g value refers only to vertical incident light (g⊥) [2], which is, however, extremely rare in practice. In fact, reflection increases the lower the angle of incidence of solar radiation is to glazing, which decreases transmittance (and to a lesser extent absorption) accordingly (Fig. C 1.15), because for each angle of incidence τ + α + ρ = 1 (Figs. C 1.11 and B 1.5, p. 52). The actual effective g value for direct solar radiation is therefore often less than g⊥ and depends on the solar radiation’s direction and orientation, the time of day and year and the proportion of direct or diffuse radiation. In reality it fluctuates widely, so some simplifying calculations are based on a general, lower g⊥

Passive solar energy use

g value acc. to Karlsson and Roos g value from measurements of individual panes

g value

Single glazing

0.87

Double glazing

0.76

g value [-]

Transparent structural elements

0.8 0.7 0.6

Thermal insulation glazing (double glazing with selective coating)

0.50 – 0.70

Triple glazing, normal

0.60 – 0.70

Triple glazing (with double selective coating)

0.35 – 0.50

Solar protection glazing

0.20 – 0.50

0.2

Transparent thermal insulation 100 – 200 mm; 0.8 < Ue < 0.9 W/m2K

0.35 – 0.50

0.1

Absorbent opaque insulating layer with single glass cover (100 mm)

0.5 0.4 0.3

0

approx. 0.10

0

10

20

30

40

50

C 1.14

value (e.g. geff specified in DIN V 18 599). In all methods of calculating the time-dependent behaviour (transient processes, temperature progression) of buildings, the g value’s dependence on the angle of solar radiation must be taken into account.

Sun-screening device 1

b=

g value (acc. to EN 410) 0.8

Internationally, the ASHRAE (American Society of Heating and Air-Conditioning Engineers) in the USA and the CIBSE (Chartered Institution of Building Services Engineers) in Great Britain calculate the SC based on a g value of 0.87 (standard value for 3 mm single glazing):

C 1.13

Optical measurements of various materials a Spectral transmittance in the solar range (usual range-measured, 0.25 – 2.5 μm wavelengths) for different materials used in and around building openings (measured values) b Idealised requirements and typical spectral transmittance and reflection curves for thermal insulation glazing c Idealised requirements and typical spectral transmittance and reflection curves for solar protection glazing C 1.14 Total energy transmittance (g value) of various radiation-permeable structural elements and materials C 1.15 g value of thermal insulation glazing depending on the angle of incidence of solar radiation C 1.16 Fc value for various sun shading devices as specified in DIN 4108

70

80 90 Angle [°] C 1.15

FC g ≤ 0.40 (Solar protection glazing)

g > 0.40

g > 0.40

Double

Triple

Double

1.00

1.00

1.00

0.65

0.70

0.65

Light colours or low levels of transparency 4

0.75

0.80

0.75

Dark colours or high levels of transparency

0.90

0.90

0.85

No sun-screening device

The b factor /shading coefficient While the g value measures energy input through a transparent structural element as an absolute parameter, other parameters such as the average transmittance factor “b” and “shading coefficient” (SC), both important parameters in widely-used cooling load calculations, define energy gains relative to specific standard glazing. The German VDI 2078 technical regulation (on cooling load calculation, July 1996 edition) defines the dimensionless b factor as the ratio of the g value of the actual glazing in question to the g value of a normal double-glazed window, which is 0.8.

60

Inside or between the panes

2

White or highly-reflective surfaces with low levels of transparency 3

Exterior Shutters, roller blinds, ¾ closed

0.35

0.30

0.30

Shutters, roller blinds, closed 5

0.15 5

0.10 5

0.10 5

0.30

0.25

0.25

Blinds, pivoting louvres at a 45° Blinds, pivoting louvres at a10°

5

0.20

5

0.15

5

0.15 5

Awning, parallel to glazing 4

0.30

0.25

0.25

Porches, awnings in general, free-standing louvres 6

0.55

0.50

0.50

1

Sunscreen must be fixed. Ordinary decorative curtains are not regarded as sun-screening devices. Precise calculations are recommended for sun-screening devices inside and between panes of glass. 3 Highly reflective surfaces with low levels of transparency, transparency ≤ 10 %, reflection ≥ 60 % 4 Low level of transparency, transparency < 15 % 5 FC values for closed sunscreens are shown for the purposes of information and should not be used to verify summer heat insulation. Closed sunscreens greatly darken the room behind them and can increase the amount of energy required for artificial light, because very little or no natural daylight can penetrate. 6 It must be ensured that the window is not exposed to direct sun. This is approximately the case if • The cover angle is β ≥ 50° for a south-facing facade, • The cover angle is β ≥ 85° or γ ≥ 115° for an east or west-facing facade. 2

The FC value can also be used for partially shaded areas of the window. DIN V 18 599-2:2011-12, A.2 stipulates that FS may not be applied. Orientations include angles in the 22.5° range. For intermediate orientations, a cover angle of β ≥ 80° is required.

South β

γ

γ

West Vertical cross section through the facade

East Horizontal cross section through the facade C 1.16

175

Passive solar energy use

SC =

g value 0.87

Planners in some countries calculate the SC for short and long-wave radiation separately. The SC for long-wave radiation is calculated by dividing secondary heat release to an interior (qi) by 0.87 (Long Wave Shading Coefficient – LWSC). The SC for short-wave radiation is calculated by dividing direct solar transmission (τe or τsol) by 0.87 (Short Wave Shading Coefficient – SWSC). The shading coefficient (FC value) One major effect of sunscreen systems is reduced energy yields, which are quantitatively assessed by the shading coefficient or reduction factor (FC value) specified in DIN 4108. The FC value indicates how energy transmittance changes due to the use of a sunscreen system and enables conclusions to be drawn about how much an interior heats up under solar radiation. An FC value of 1 (or 100 %) indicates no solar protection at all. Figure C 1.16 (p. 175) shows the FC values of common sunscreen systems. If a system consists of special glazing and solar protection, its g value will be as follows:

S = TL / g

Energy transmittance through an entire system depends on various interactions between sunscreens and glazing, e.g. on reflection between individual layers, the diffusion or refraction of solar radiation, on the glazing’s spectrum-dependent transmittance properties and on the solar protection device. This means that the same sunscreen can have different effects when combined with different glazing, so the FC value is not a fixed parameter for a sunscreen, but always depends on glazing quality. Combining an external blind with thermal insulation glazing with a g value of 0.6 can, for example, ensure that only 15 % of solar radiation energy hitting the glazing reaches the interior, so its reduction factor is 15/60 = 0.25 (g value (total) /g value (glazing) = Fc value). Combining a blind with sunInside

Glass 4 mm

Total: 13 %

Direct transmittance 85% 6%

Secondary radiation emission and convection

2%

Total: 87%

Solar radiation 100 %

Reflection 7%

Secondary radiation emission and convection C 1.17

176

Emissivity Emissivity ε is a material-specific, temperaturedependent property of a material’s surface. It describes the extent to which a material releases thermal radiation into its environment. Together with other factors that result from the exchange of radiant heat, it is explained in detail in the section on “Thermal radiation and emissivity” (p. 52). Emissivity plays a major role in current solutions involving functional coating systems on glass. Figure B 1.7 shows some exemplary values (p. 52). Selectivity Selectivity is the ratio between transmittance in the visible spectral range TL and the total energy transmittance coefficient g:

g value (total) = FC value · g value (glazing)

Outside

screening glazing with a g value of 0.3 makes the entire system more effective and reduces the proportion of transmitted radiation energy to 9 %, although there is less relative improvement from the solar protection device. The reduction factor in this example is 9/30 = 0.30 (Fig. C 1.16, p. 175).

S stands for “selectivity”. Put simply, the goal in using selective materials is to provide plenty of light but little heat, i.e. to use materials that admit abundant visible light through a structural element while filtering out or ideally reflecting invisible, yet energyrich solar radiation in the near infrared range. This can be done with many materials by adding filter layers or modifying the material’s structure. Daylight and artificial light

Energy input through building openings cannot be dealt with independently of the issue of “daylight and artificial light”, because visible light is part of the solar spectrum. Measures for controlling energy input therefore inevitably and directly affect the supply of daylight and as a result, the need for artificial light in the building, so the g value greatly influences the amount and quality of daylight in a space. The most important daylight and artificial-light parameters are described below. Illuminance Illuminance Ev (v = visual) is an objective measure of the intensity of light perceived by people. It describes the ratio of a flow of light measured in lumen [lm] parallel to a receiving surface orientated perpendicularly to the surface and is specified in lux [lx]: 1 lx = 1 lm / m2 “Illuminance” can also be interpreted as the ratio of luminosity of a punctiform light source, measured in candela [cd], to the square of distance in metres.

1 lx = 1 cd / m2 This is relevant if the effect of a single artificial punctiform light source in the immediate environment is considered. In contrast, distances (e.g. the distance of cloud cover) do not influence light intensity outdoors, because the distance from the light source, the sun, is always enormous. Illuminance is measured with a lux meter. German standards require various minimum degrees of illuminance [3]. 100 lx is required for general lighting in workspaces. Required minimum workplace lighting depends on the visual task involved. It is 300 lx for permanently occupied workspaces, while spaces used for computer work must have at least 500 lx at desk height. The illuminance levels required by standards also depend on the activity, the room layout and how close a workstation is to windows. For safety reasons, at least 7.5 lx is prescribed for traffic routes during usage, while illuminance for emergency escape routes may not fall below 1 lx. In assessing illuminance levels, it should be noted that at a distance of 1 metre the illuminance (brightness) of a candle, which typically has an illuminance of 1 cd, is 1 lx. At a distance of 2 metres, it is just 0.25 lx. On a cloudy winter’s day, illuminance outside is approximately 2,000 – 4,000 lx, on a cloudy summer’s day it is about 20,000 lx and on a bright sunny day it is more than 100,000 lx. Luminous intensity – glare and contrast Levels of absolute brightness or brightness contrast that are too high can cause glare. The crucial parameter here is luminous intensity Lv, which is an objective measure of the brightness of a luminous or illuminated surface (e.g. a translucent textile illuminated by the sun, a sunscreen or pane of frosted glass) as perceived by the human eye. Luminous intensity is measured in candela per m2 [cd/m2]. The human eye can perceive a very wide range of brightness, which the eye fully utilises as it adapts by widening and narrowing its pupil like the aperture in a camera. People can perceive differences in luminous intensity of more than 10 %. While our eye very quickly adapts to small fluctuations in brightness, adapting from one extreme to the other can take up to 30 minutes. Above a certain brightness, “absolute glare” or dazzle sets in. The eye’s rods, which are responsible for colour perception, become overstrained and saturated. This individually varying limit ranges from 100,000 to 1,000,000 cd/m2. Our eye’s limited adaptability means that much lower luminous intensities can cause glare if luminous intensity contrasts are too great (local or adaptation glare). This phenomenon often affects people working with computer screens near windows. Typical luminous intensity values [cd/m2] include,

Passive solar energy use

• • • • • • • •

Lowest perceptible brightness Screen Surface of the moon Average cloudy sky Average clear sky Cool white fluorescent tube Absolute glare Sun’s disc at midday

0.00001 100 – 500 2,500 1,000 – 6,000 2,000 – 12,000 11,000 from 100,000 1,500,000,000

To avoid high levels of luminous intensity contrast, an environment’s luminous intensity should be 2/3 to 1/10 of the ambient luminous intensity (e.g. the luminous intensity of a workstation screen). Daylight must be glare-free, with active solar protection and evenly distributed in the room. If this is not ensured by sunscreens, glare protection must be provided to limit contrasts. This inevitably reduces absolute amounts of light and increases the energy required for artificial light. It should also be noted that interior glare protection may not have an additional sunscreen function and absorption further increases energy input. Translucent, light-diffusing surfaces (e.g. textured or frosted glass, fabrics and technical textiles) installed on west-facing, south-facing or east-facing facades are likely to cause glare. Without exterior sunscreens, these materials allow very high levels of luminous intensity into an interior. Their use in the upper areas of windows, where they can improve the supply of daylight in the depths of a space, is, however, not critical. Colour rendering Many measures for controlling g-values influence the amount as well as the quality of daylight in a room. Colour rendering, which measures the “naturalness” of daylight illuminating a room through an opening, is an important parameter here. Coloured glass, added functional layers or the reflective surfaces of sunscreen systems can change the spectral composition of daylight in an interior and distort colour rendering. Colour rendering is explained in detail in the section on “Colour rendering and the colour rendering index” (p. 79).

Insulating glazing – technical factors involving solar radiation Insulating glazing units, which are now standard components in building openings, greatly influence a building’s energy balance. Among

the heat transport phenomena described in the section on “Heat conduction, heat flows and thermal radiation” (p. 51f.), thermal radiation is particularly important to insulating glazing because various technologies have been developed that allow such glazing to very precisely adapt to deal with it.

τvis = 40 % τsol = 22 %

Energy exchange through a single pane of glass

Figure C 1.17 illustrates the physical effects on a single, 4 mm-thick pane of float glass on a sunny day that produce the following result: Of the 100 % of the incident radiation – depending on the angle of incidence – about 85 % is transmitted and around 7 % reflected. The remaining 8 % is absorbed and heats the pane. This energy is then released through secondary thermal radiation (in the long-wave IR range) and convection, both inside and out. Depending on conditions (air temperature, wind, the built environment), the proportions fluctuate greatly. In this example, the release of secondary heat is higher towards the outside (6 %) than on the inside (2 %). Of the total solar energy that hits a pane (100 %), 13 % remains on the exterior while 87 % reaches the interior.

Approx. 45 % light Approx. 50 % solar thermal radiation Approx. 5 % UV radiation

Ug = 1.1 W/m2K

C 1.19 Incidence 100%

Reflection 37%

79%

Transmittance 16%

Remission 27% 21%

15%

Secondary heat release

5%

Effects of functional coatings

Coatings play a crucial role in improving the energy parameters of modern functional glazing, influencing its optical and thermal properties, at best without being visible. The general physical fundamentals on the issue of “Thermal radiation and emissivity” are outlined on p. 52, with various technical implementation options summarised in the section on “Coatings” (p. 89ff.). This chapter focuses on the links between functional layers, heat transport and solar energy. Modern functional layers used in multi-pane insulating glazing units have two main, partly contrary goals (Figs. C 1.13 b and c, p. 174): The first goal is to increase the glazing’s selectivity, giving it high visual transmission and a low g-value, i.e. allowing in abundant light but little heat. Glazing with this kind of optimised selectivity is called sun-screening glazing. Its U-value does not necessarily have to be low. The second goal is to improve thermal insulation while admitting as much light as possible,

Double-paned solar protection glazing

Double-paned thermal insulation glazing

Triple-paned thermal insulation glazing

0.17– 0.50

0.48 – 0.62

0.35 – 0.60

Heat transfer coefficient Ug [W/m2K]

0.9 –1.3

0.9 –1.3

0.5 – 0.8

Luminous transmittance TL

0.3 – 0.7

0.7 – 0.8

0.70 – 0.75

Selectivity S

1.7– 2.2

1.25 –1.45

1.2 –1.6

Total energy transmittance g

Solar radiation

Solar protection glass

Glare protection (interior) C 1.20

i.e. a high g value and the lowest possible U value. As the primary aim here is an optimised heat transfer coefficient (U value) and with it improved thermal insulation, this is called thermal insulation glazing (for improving thermal insulation, not protection from summer heat). Figure C 1.18 shows specific values for typical thermal insulation and sunscreening glazing. All functional layers also seek to ensure: • High levels of colour neutrality in transmission, regardless of the viewing angle (see “Colour rendering and the colour rendering index”, p. 79) • Low levels of reflection in the spectral range of visible light and the highest possible level of colour neutrality • Long-term stability and robustness of typical functional layers in spaces between the panes in the manufacturing process

C 1.17

Movement of the sun’s rays through a single pane of float glass with typical values (solar spectral range) on a sunny day C 1.18 Typical properties of common types of thermal insulation and solar protection glazing C 1.19 Solar protection glazing with selective coatings C 1.20 Combination of solar protection glazing and interior glare protection C 1.18

177

Daylight transmittance TL

Passive solar energy use

0.8

• Long-term stability and robustness to deal with mechanical influences for coating systems that are exposed on the interior side as well as the ability to resist weather for those on the outside

0.7 0.6 0.5

Thermal insulating glazing Sun-screening glazing

0.4 0.3 0.2 0.1 0

Spectral transmittance

0

0.1

0.2

0.3

0.4 0.5 0.6 0.7 0.8 Total energy transmittance g C 1.21

1.0 0.9

τmin(λ)

0.8

τsol /τvis = 0.334

0.7 0.6 0.5 τsol /τvis = 0.51

0.4 0.3

Sλ(λ)

0.2

The effectiveness of sun-screening glazing is based either on increased absorption due to the use of coloured glass (now not very common) or greater reflection of solar radiation (especially beyond the range of visible light) with special, extremely thin noble metal coatings (usually based on silver), which meet the physical optimisation goal of maximum selectivity. Figure C 1.19 (p. 177) shows the principle of such glazing. Figure C 1.20 (p. 177) shows the solar radiation processes that occur with a combination of sun-screening glazing and interior glare protection. Since visible light makes up about 45 % of solar radiation, glazing that admits all visible light (TL = 100 %) and completely reflects UV and infrared radiation would have a g value of 0.45. In this theoretical case, its selectivity would be S = 1.0 / 0.45 = 2.22. Reducing the g value to below 0.45 also entails blocking out visible light, which diminishes the supply of daylight to a space.

0.1 0 0

500

750

1000

1250 1500 Wave length [nm] C 1.22

C 1.23

Figure C 1.13 a (p. 174) shows that the transmission curves of sun-screening glazing usually have the form of a bump, i.e. all light frequencies are similarly strongly reduced. This means that the colour impression of transmitted light remains, but selectivity is limited to a value of 2.2. If slight changes in colour are tolerable, more border areas of visible light can be filtered out from the 490 – 630 nm range, which is optimum for the human eye. Panes of glass currently available on the market can have selectivity values up to 2.5 (Fig. C 1.21). Research is continuing into a new type of coating that pursues a different strategy. A solar protection coating reduces the proportion of radiation in the blue and red spectral range, so incoming light appears green. The transmission curve of this special sun-screening glass is M-shaped (“M glass”, blue line Fig. C 1.22). Filtering out radiation in a narrow range of 500 nm (green) can compensate for the green shift, reducing the transmission of green light so that light passing through it is largely neutral in colour. This coating system results in a ratio of solar to visual transmission of just 0.33, which is a selectivity of about 3. Its effectiveness means that “M glass” may make a major contribution to simplifying building technologies in future. Various types of solar protection glass with variable light and energy transmittance are now available. The main technical types of these relatively new options are described in the chapter on “Materials, components, types of constructions” (p. 86ff.). Among them

178

are technical options for treating glass surfaces that can also block out solar radiation, such as special microstructure coatings (see “Microstructured coatings on glass”, p. 90).

Another effective way of optimising thermal radiation properties is to modify reflection in the far IR range (not in the solar radiation range, but in the long-wave thermal radiation range). High levels of reflectivity and low absorption in this spectral frequency range, which is vital to interior temperatures, result in low surface emissivity ε. In physical terms, this correlates with specific absorption α and can be calculated from reflectivity ρ and transmittance τ as follows: ε = 1 - ρ - τ Such surfaces are called low-emissivity (Low-E) coatings. Uncoated glass has a surface emissivity ε of 84 %, while currently available thermal insulation coatings have a ε of less than 5 % (silver coatings just 3 %). Low-E coatings have been used in insulating glazing since the early 1980s. They reduce heat loss from an interior by lowering heat emission from the inner pane outwards, greatly reducing the glazing’s U value. Thermal insulation coatings are highly transparent for the short-wave part of solar radiation and highly reflective of long-wave thermal radiation (especially 3 to 50 μm). Similar sun-screening glass coatings have additional absorbent and/or reflective components that produce the desired solar radiation properties. The main influential factor of these is the thickness of the silver coating. Double-paned thermal insulating glazing is usually installed with the coating on the side of the inner pane facing the space between the panes (position 3), while the uncoated pane is on the outside [4]. The U value depends on the direction of installation whereas the g value varies only slightly with a change in the coating’s position. The further inside a coating is, the higher the g value of the thermal insulating glazing (and total solar gain) will be.

C 1.21

Connection between total energy transmittance and transmittance in the visible range of selected solar protection glazing available on the market. Points on the straight line have a selectivity of 2. C 1.22 Transmission curve of “M-glass” with very high selectivity (> 2.2), red curve: standard spectral distribution of solar radiation; green curve: transmission of typical solar protection glazing; blue curve: transmission of “M-glass” C 1.23 “Lighter test” of double insulating glazing. Reflections of the lighter flame can be seen clearly in the individual glass boundary layers (here 4). Coatings can be recognised by the green or red reflections they throw.

Unchanged

Unchanged

Horizontal

Unchanged Unchanged

Unchanged

Unchanged

Fold out

Vertical

Turning

Low-E coatings are sometimes used outside the space between the panes of insulating glass units, e.g. on the inside of single panes to improve the glazing’s insulating effect. The coating makes the pane reflect part of the thermal radiation a room emits onto the pane back into the room. Such a coating on the outer pane of highly thermally insulating triple glazing can stop panes from freezing because they release less radiation energy into the cold night air on winter nights and do not cool down as much. Both applications require very robust coating systems because they are not protected in the space between the panes but are exposed to weather and can be touched. Their surfaces also need to be cleaned to maintain their effect, so only coating systems that are much more resilient than coatings in the space between the panes and do not corrode can be used here, usually pyrolytic coatings (see “Pyrolytic coating”, p. 89).

Sliding

Passive solar energy use

Perpendicular to the facade

Unchanged

Unchanged

Unchanged

Unchanged

Unchanged

Unchanged

Around a vertical axis

Unchanged Unchanged

Unchanged

Unchanged

Unchanged

Unchanged

Reduced

Reduced

Reduced

Reduced

Reduced

Reduced

Reduced

Unchanged

Reduced

Around a horizontal axis

Glazing with multifunctional layers

Folding (turning / sliding)

The position of coatings plays a major role in most modern multi-pane insulating glazing units with one or more functional coatings because their position influences the effect and appearance of functional glazing. Often the question is raised of whether glazing has been manufactured in accordance with the specifications or which way round panes should be installed. Since coatings are designed to be as neutral as possible when looked through, they and their position(s) in a glazing unit are hard to identify with the naked eye when looked at or through normally. The “lighter test” is a simple way of testing the position of functional layers on a building site or in a building. It is based on the fact that coatings look neutral in transmission and differences can usually only be detected by directly comparing an uncoated or differently coated surface as typical coatings do not accurately reflect the colour spectrum. A coating will change the colour of the reflection of a lighter flame so that it appears distinctly greenish or reddish (Fig. C 1.23).

Reduced

Horizontal

Vertical

Greatly reduced Circular

Gathering

The position of functional coatings

Around an axis perpendicular to the element

Greatly reduced Greatly reduced

Greatly reduced

Horizontal

Greatly reduced Greatly reduced Vertical

Greatly reduced Circular

Rolling

Most sun-screening insulating glazing units have multifunctional coatings to provide both sun screening and thermal insulation. Panes with such coatings are generally installed with the coating on the side of the outer pane facing the space between the panes (position 2).

Greatly reduced Greatly reduced Horizontal

Greatly reduced

Greatly reduced Greatly reduced Greatly reduced C 1.24

Classification of common elements and various types of movement. Notes above drawings refer to “packaging” (changes in size) of moveable elements.

Vertical

C 1.24

179

Passive solar energy use

Moveable elements in and around building openings

N

C 1.25 C 1.25 C 1.26

Geometry of an effective sun-screening system depending on orientation Comparison of various sun-screening systems

One special feature of building openings, such as windows, doors or ventilation openings, is their controllability. This is usually built into the structure in the form of additional moveable elements in front of, behind or inside the opening. As well as window elements, these can be all kinds of shutters, drapes, blinds, louvres, curtains and more. Elements can be unchanging (e.g. an opaque wooden folding shutter) or have variable properties (e.g. an adjustable sunscreen blind). Once always hand-operated, motor-driven elements are now often used, either acti-

vated by people or automated. Over various eras of architectural history, climatic zones and regional cultural traditions, a huge diversity of structural solutions and versions has developed [5]. Figure C 1.24 (p. 179) illustrates the range of different types of movement. Moveable sunscreen elements

Sunscreen systems aim primarily to limit solar energy input to an optimum level. They are required in northern latitudes in summer, but not all year round. Controllability is very important in winter because solar energy input, which can help to heat rooms, is otherwise entirely or partly blocked. Moveable sunscreen

Triple solar protection glazing

Double blind glass

Triple blind glass

Double insulating glass with exterior blinds

Triple insulating glass with exterior blinds

Solar protection at Pos. 2, low-E coating at Pos. 5

Low-E coating at Pos. 3

Low-E coating at Pos. 3 and Pos. 5

Low-E coating at Pos. 3

Low-E coating at Pos. 3 and Pos. 5

Sunscreen

None

Integrated blinds

Integrated blinds

Exterior blinds

Exterior blinds

FC (standard, DIN 4108-2:2013)

1.0

0.65 – 0.85

0.70 – 0.90

0.25 (45° louvre position)

0.25 (45° louvre position)

FC (practice)

1.0

0.15 entirely closed / 0.30 at 45° louvre position

0.15 entirely closed / 0.30 at 45° louvre position

0.20 – 0.12

0.20 – 0.12

Sunscreen, total g value

~ 0.25

~ 0.08

~ 0.05

0.12 – 0.08 (45° louvre position)

0.10 – 0.06 (45° louvre position)

Thermal insulation total Ug value [W/m2K]

0.6 – 0.7

1.0 – 1.1

0.6 – 0.7

1.0 – 1.1

0.6 – 0.7

Light transmission max.

~ 30 – 40 %

~ 80 %

~ 70 %

~ 80 %

~ 70 %

True colour rendering

--

+

+

+

+

Integratable light control

No

Yes

Yes

No

No

Interior sight screens and glare protection

Necessary

Depending on louvre system

Depending on louvre system

Depending on louvre system

Depending on louvre system

Reflection / reflective effect

High reflective effect

Low reflective effect due to reflecting louvres

Low reflective effect due to reflecting louvres

Low reflective effect

Low reflective effect

Soundproofing (transmission from outside)

++

+

++

+

++

Facade weight

Heavy

Light

Heavy

Light

Very heavy

Lightness, lightweight, transparency

-

++

++

-

+

Structural sealant glazing possible

Yes

Yes

Yes

No

No

Sight screens possible

No

Yes

Yes

Yes

Yes

Automatic and individual operation possible

No

Yes

Yes

Yes

Yes

Maintenance cost and effort

None

None

None

High

High

Cleaning cost and effort

Low

Low

Low

Very high

Very high

Energy costs for operation

None

Very low

Very low

Low

Low

Cost and effort involved in replacing defective solar protection

Not applicable

Very high

Very high

Low

Low

Investment required

Low

Average

Average

Low

Average

Typical application /remarks

For shaded facades, with a low proportion of window area

Independent of the weather

Independent of the weather

Low-rise administration Housing construction buildings, housing

Coating

180

Pos. 1 Pos. 2 Pos. 3

Pos. 4 Pos. 5 Pos. 6

Passive solar energy use

elements are one of the most important components in planning passive solar energy use because they greatly influence a building’s energy balance. The following criteria must usually be taken into account and managed in planning: • Reducing of solar energy input to an optimum level • Securing an adequate supply of daylight, even with active solar protection • Maintaining views from inside to out In practice, distinctions are made among various approaches: 1. Is the sunscreen fixed or adjustable? Exterior conditions (position of the sun,

weather) and demands arising from the use of a space (glare protection, shading) vary over time, so adaptable systems are better than inflexible, non-adaptive systems, which are almost always an inadequate compromise. 2. Where is the sunscreen in the building envelope? Positioning outside the thermal envelope is ideal because it keeps energy input from the secondary thermal radiation of the sunscreen system itself (caused by its heating in the sun) to a minimum. If a sunscreen is on the inside of a building’s opening, the interior absorbs solar radiation, which adds considerable amounts of extra heat. If high wind loads on

a facade, excessive cleaning cost or effort, or the design concept make exterior sunscreens impossible, they can be installed for protection in the space between the panes of an insulating glazing unit or in the space between a double-layered window or a facade. A sunscreen system’s geometry plays an important role in this context. It should be designed to fit in with the facade surface orientation and the course of the sun. Figure C 1.25 shows how such optimised systems vary for south-facing, east-facing and west-facing facades (here and below referring to the northern hemisphere and Central Europe). Southfacing horizontal structures provide both effec-

Porch outside

Awning outside

Roller blind inside

Double facade Double insulating glass

Double facade Double insulating glass

CCF facade Double insulating glass

CCF facade Triple insulating glass

Low-E coating at Pos. 5

Low-E coating at Pos. 3 and Pos. 5

No coating, all white glass

No coating, all white glass

Blinds between panes of glass

Blinds between panes of glass

Blinds between panes of glass

Blinds between panes of glass

Porch outside

Awning outside

Roller blind inside

0.25 (45° louvre position)

0.25 (45° louvre position)

0.25 (45° louvre position)

0.25 (45° louvre position)

0.5

0.25

0.65 – 0.90

0.15

0.15

0.20 – 0.12

0.20 – 0.12

0.5 – 1.0

0.1 – 0.4

0.35

~ 0.12 – 0.10

< 0.08

~ 0.11

~ 0.08

0.7 – 0.8

< 0.6

~ 1.4

~ 0.8

~ 70 %

~ 60 %

~ 70 %

~ 60 %

+

+

+

+

No

No

Yes

Yes

No

No

Depending on louvre system

Necessary

Depending on louvre system

Depending on louvre system

Depending on system

Existing

Low reflective effect

Low reflective effect

Low reflective effect

Low reflective effect

High reflective effect (depending on solar protection coating)

Low reflective effect

+

++

++

++

Extremely heavy

Extremely heavy

Heavy

Very heavy

Light

Depending on glazing quality

Depending on glazing quality

+No

High reflective effect (depending on solar protection coating)

Depending on glazing quality

-

-

+

+

+

+

o

No

No

No

No

No

No

Yes

Yes

Yes

Yes

Yes

No

No

Yes

Yes

Yes

Yes

Yes

No

Yes

Yes

High

High

Average

Average

None

Very high

Low

Extremely high

Extremely high

Low

Low

Low

High

Low

Low

Low

High

High

Very low

Low

Very low

Low

Low

High

High

Depending on system

High

Very low

High

High

Very high

Very high

Low

Low

Very low

Independent of the weather, high sound insulation requirements

Independent of the weather, high sound insulation requirements

Independent of the weather, high sound insulation requirements, high transparency requirements

Independent of the weather, high sound insulation requirements, high transparency requirements

Southern facade, low standard

Low standard, often not adequate as sole sun screening system, interaction with window ventilation must be taken into account

Atria, facades with low proportion of window surface, mostly combined with solar protection glazing C 1.26

181

Heat losses kWh/m2a]

Passive solar energy use

100 85.5

85.5

Loss through frames and edge bonds Loss through glass surface

80 By comparison: masonry wall with 14 cm EPS U = 0.25 W/m2K

58.7 5!

Window with 2 panes of thermal insulation glazing with argon gas filling Ug = 1.1 W/m2K Uf = 1.2 W/m2K g = 0.6

Fa cto r

60 40

16.7

20

Solar gain

0

-20 -40 -60

Window with 2 panes of sun protection glazing with argon gas filling Ug = 1.1 W/m2K Uf = 1.2 W/m2K g = 0.4

Northern orientation 29.7

Northern orientation 19.8

Northern orientation 24.7

Southern orientation 98.7

Southern orientation 65.8

Southern orientation 82.2

Window with 3 panes of thermal insulation glazing with argon gas filling, Insulated frames Ug = 0.7 W/m2K Uf = 0.8 W/m2K g = 0.5

-100 C 1.27

τ=

0.9

A sun-screening system’s performance is indicated by the shading factor or reduction ratio (FC value) (see “Shading coefficient”, p. 175 and Fig. C 1.16, p. 175). In general, productspecific manufacturers’ data is more useful in detailed planning than standard values. Figure C 1.26 (p. 181) compares various sun-screening solutions in terms of the essential criteria of the serviceability of triple solar protection glazing without any other protection from the sun and suggests various solutions for integrating solar protection into the space between the panes of multi-pane insulating glazing units and between the panes of a casement window or double facade. Using sun-screening devices to minimise the g value also usually means significantly reducing daylight transmission when they are closed, so such solutions can have counterproductive effects on power requirements and heat input because artificial lighting may be required during the day. Various sun-screening solutions for the spaces between panes are described in more detail in the section on “Combinations of materials in glazing in buildings” (p. 98ff. and Figure B 2.34, p. 99. Figure B 2.35, p. 99, shows a version of such a solution).

h 30

0.7 0.6 0.5 0.4 0.3 0

182

0.5

1

1.5 2 2.5 Heat gain / heat loss C 1.28

Transparent opening coverings and heating energy requirements

Size and layout of openings Building openings carry out and/or regulate major functions such as energy input, supply of daylight, solar protection and ventilation, so making optimum use of a building’s passive solar energy potential depends on their planning [6]. Successful planning of openings is closely connected with more general influential factors such as, • Interior geometry (especially the depth of spaces)

The development of highly effective thermal insulating glazing with inert gas fillings, coatings that reflect thermal radiation, and insulated and thermally separate frame profiles has greatly changed this image since the 1980s. Depending on its glazing quality and orientation, a window can have a neutral or even positive energy balance, measured over an entire heating period (Fig. C 1.27).

5h

τ=

0.8

Facade openings contribute in a special way to the energy balance of rooms and buildings. On the one hand, the heat transmission coefficient of even high-quality thermal insulation glazing, at Ug = 0.6 … 1.1 W/m2K, is three to eight times as high as that of opaque exterior wall elements now commonly used in Germany. Windows and similar opening elements are therefore responsible for an excessively high proportion of transmission heat loss, in relation to the envelope surface. On the other hand, transparent structural elements allow solar radiation to enter a building, where it is absorbed by space-enclosing structural elements, furnishings and fixtures, and heats them. Whether this energy input makes a welcome contribution to heating a building or causes unpleasant overheating depends on exterior conditions, on the building’s characteristics, and on inner heat loads, which also result from its use. Glazing, furnishings and fixtures suitable for controlling the passage of heat and solar radiation must therefore be chosen in the context of a building’s overall energy system. In housing construction, the focus is usually on reducing heating energy requirements in winter, while for offices and administrative buildings the emphasis is on protection from summer heat.

Over the centuries, facade openings have been conspicuous thermal weak points in building envelopes. This is especially true of openings with single glazing and in attenuated form but also with coupled windows and early forms of air-filled insulating glazing units.

17

Utilisation level

1.0

Ideally, the most precise information possible should be available on issues such as load profiles in a suitable temporal resolution at an early phase of planning. This will enable planners to develop an optimum ventilation plan and concepts for regulating, controlling and automating elements. Building openings in the building’s energy balance

-80

tive protection from a high summer sun and visual contact with the outside. The reflection properties of solar protection systems can influence how much daylight is deflected into a space. Horizontal geometry is not advisable on east and west-facing surfaces because the summer sun in the morning and afternoon is so low that any horizontal structure facing it needs to be almost completely closed. Vertical structures are much better for these two sides. They will ensure functional quality, even when the sun is low, and, similar to a horizontal structure on a south-facing facade, provide effective solar protection, visual contact and sufficient daylight. Slightly sloping vertical structures are necessary on a northfacing facade because in summer the sun rises in the northeast and sets in the northwest (Fig. C 1.3, p. 171). In weighing up the significance of solar protection for a building’s energy balance, its main orientations should be prioritised as follows: west, east, south. Figure C 1.25 (p. 180) shows an ideal geometric principle that offers planners a wealth of possible configurations.

• Type and distribution of thermal mass • Ventilation (minimum air exchange, natural/ mechanical, through the opening or not) • Internal thermal loads and emissions • Type of usage • Plant-engineering technical conditions of the building

Some of the heat gains shown in Figure C 1.27 accumulate at times when yield exceeds current heating needs, so they cannot be completely used. The proportion of actually useable heat gains is indicated by the utilisation factor η, which can be calculated as specified in DIN V 18 599-2 and DIN EN ISO 13 790. It is based on the time constant τ of the building, i.e. its thermal inertia, and the ratio of heat gains to heat losses. The calculation takes into account the fact that “thermally heavy” massive buildings store accumulated heat gains in structural components during the day and release them into the interior later. They therefore have a utilisation factor higher than that of light buildings, into which incident sunlight causes a faster, possibly undesirably high input of heat that must then be discharged by means of ventilation, thereby losing any benefit from the heat (Fig. C 1.28). The declining utilisation factor resulting from rising heat gains also comes into play when increasing the proportion of window surface. While increasing the window area in a south-facing facade can greatly reduce a room’s heating energy requirement, the effect often is diminished if there is a very high proportion of window area or can even reverse as heat losses increase due to the higher U value of a window compared with an opaque wall. Factors that greatly influence this effect include an optimum window to wall surface ratio, the building’s energy standard and a window’s thermal properties (Fig. C 1.29). Figure C 1.30 shows the influence of a window’s orientation on a dwelling’s heating energy requirements. If double-paned thermal insulating glazing is used, the window area can only be increased on the south-facing side without also increasing the heating energy requirements. This effect is even clearer in office buildings (Fig. C 1.31), where higher inner heat loads already largely meet heating

needs, so additional solar gains are of almost no use. Here, regardless of the building’s orientation, a high proportion of window area results in undesirable heat in summer and greater heating energy requirements during the heating period due to higher heat losses through the window surfaces. It is especially adverse if an exterior sunscreen used to screen glare also blocks out welcome rays of the sun in winter. It should be noted that a space’s heat load grows when the window surface is increased, because a heating system must supply the desired room temperature, even in adverse conditions such as low outside temperatures and a lack of solar irradiation. The increase in window area affects both the heat generator and the release of heat into the space. In spaces heated by radiators or radiant panel heating, large expanses of window can usually be compensated for by increasing the heating area or by higher operating temperatures. This compensation option is not available for buildings heated solely by incoming air, such as passive houses. Here, the heating load in relation to floor space may not exceed a maximum of 10 W/m2 [7]. Even if windows suitable for passive houses with UW ≤ 0.8 W/m2K are used in a strictly southfacing building, this will limit the proportion of possible window surface in a facade, as shown in Figure C 1.32, p. 184. Summer heat insulation

With large facade openings now common, solar radiation entering into the space behind them, even in the transitional months, can cause undesirable overheating, especially if it coincides with high inner heat loads, as is the case in office buildings. A ventilation and shading concept specifically designed for the space should prevent undesirable overheating and limit the costs of energy-intensive cooling. The following projectable building characteristics affect the energy required for summer heat insulation:

80

70 Low-energy houses 60

50

40

30 Passive houses 20

10

0 0 10 20 30 40 50 60 70 Proportion of glazed surface, south-facing facade [%] Ordinary insulating glazing Ordinary insulating glazing with pyrolytic coating Double thermal insulation glazing with silver-oxide coating and argon gas filling Triple thermal insulation glazing with two pyrolytic coatings and krypton gas filling Triple thermal insulation glazing with two silver oxide coatings and krypton gas filling Triple thermal insulation glazing with low-iron clear glass, with two silver-oxide coatings and krypton gas filling N Annual spatial heating requirement [kWh/m2a]

Utilisation factor and window orientation

Heating requirement per m2 of living space [kWh/m2a]

Passive solar energy use

surface ratios. Parameters: dwelling (W ≈ D ≈ H: 4 ≈ 6 ≈ 3 m) with an exterior facade Uwall = 0.25 W/m2K, all other surfaces adiabatic, heavy, solid construction, glazing Ug = 1.25 W/m2K, g = 0.61, Tinterior: 20 – 26 °C, climate: Munich (D), average internal heat load: 3 W/m2, air exchange 10 l/s, heat recovery rate of 80 % C 1.31 Heating energy requirements for an office depending on orientation, with various window surface ratios. Parameters: office (W ≈ D ≈ H: 4 ≈ 6 ≈ 3 m) with an exterior facade Uwall = 0.25 W/m2K, all other surfaces adiabatic, mediumweight construction, glazing Ug = 1.25 W/m2K, g = 0.43 (no sun shading), nominal value for activating sunscreens: 300 W/m2 on the facade, Tinterior: 20 – 26 °C, climate: Munich (D), internal heat load: 20 W/m2 by day and 10 W/m2 at night / on weekends, air exchange 48.4 l/s by day and 8.4 l/s at night or on weekends. Heat recovery rate of 80%

Annual spatial heating requirement [kWh/m2a]

Transmission heat losses and solar gains of various window structures over the heating period (mid-October to mid-April), calculated in keeping with DIN V 18 599-2:2011-12, test reference year 2010, for Potsdam (D) C 1.28 Utilisation of heat gains as specified in DIN V 18 599-2:2011-12 for two buildings with different heat storage capacity depending on the ratio of heat gains to heat losses (green: solid, well-insulated building; blue: light, badly insulated building). The dotted line shows the theoretical maximum (internal and solar heat gains completely meet heating requirements). C 1.29 Heating energy requirements for a low-energy or passive mid-terrace house, depending on the proportion of window surface in a south-facing facade and on glazing quality C 1.30 Heating energy requirements for a dwelling depending on orientation and different window

S

W

C 1.29 S No sun screening

32 28 24 20 16 12 8 4 0 20

C 1.27

E

N

30

E

40

S

80 50 60 70 Proportion of window surface [%] C 1.30 W S No sun screening

20 18 16 14 12 10 8 6 4 2 0 20

30

40

80 50 60 70 Proportion of window surface [%] C 1.31

183

Passive solar energy use

Required heating capacity [W/m2]

Limit value Passive house

Hof (D) Cool cloudy day Cold, clear day

Hanover (D) Cool, cloudy day Cold, clear day

16 14 12 10 8 6 4 2 0 0 10 20 30 40 50 60 70 80 90 100 Proportion of window surface, south-facing facade [%] C 1.32

Annual spatial cooling requirement [kWh/m2a]

North

East South

West West II

32 28

• Geometry and orientation • Surface area and optical properties of transparent structural elements, especially the total energy transmittance (g value) • Shade from surrounding buildings, vegetation and projecting structural elements (a structure’s own shade) • Fixed and moveable sun screens • The building’s thermal inertia • Heat transfer through exterior structural elements • The possibility of cooling storage mass by active or natural night ventilation

24 20 16 12 8 4 0 20

30

40

50 60 70 80 Proportion of window surface [%] C 1.33

Heating Cooling Lighting

Energy requirement [kWh/m2a]

Total energy requirement

0

184

20 40 60 80 100 Proportion of glazing, south-facing facade [%] C 1.34

West-facing and east-facing facades in Central Europe must be planned especially carefully because the sun’s flat angle of incidence means that they will be exposed to a higher solar radiation per square metre on summer mornings and evenings than south-facing facades (Fig. C 1.5, p. 171). West-facing facades are more critical in this context than east-facing facades. While heat loads incurred through openings in an east-facing facade in the morning can be at least partly discharged by increasing the exchange of air, this is not really possible in the afternoon due to the increased outdoor air temperatures. Its steep angle of incidence means that direct radiation on south-facing facades in summer can be largely blocked by roof overhangs or horizontal shading elements. Planners often dispense with solar protection entirely on north-facing facades, failing to note that northern-oriented surfaces are also exposed to direct sun on summer mornings and evenings. Diffuse solar radiation reflected from the ground and environment into a space through large areas of glass can also reach values so high that shade becomes necessary. The rule of thumb is that cooling energy requirements increase almost linearly with the proportion of window surface (Fig. C 1.33). Verification process DIN 4108-2 stipulates a simple verification process for summer heat insulation based on establishing a maximum permissible solar

input value Sper by adding a series of partial values that reflect the building’s relevant properties. It takes into account • The use of the building (residential or nonresidential building) • Location (with Germany divided into three climatic regions) • The building’s construction type (light, medium, heavy) and night ventilation options • The surface area of all the space’s windows relative to its floor space • The use of sun-screening glass • The inclination and orientation of window surfaces • The possibility of using passive cooling techniques This value is compared with the actual solar input value Sact: Sact = Σj (AW,j · gtot) / AG AW Window surface area(s) in m2 gtot Total energy transmittance taking into account the reduction factor FC provided by sunscreens (see “Shading coefficient”, p. 176), e.g. simplified in accordance with DIN 4108-2 via gtot = FC value · g AG Net floor space of the space or a group of spaces in m2 For residential buildings with rooms of the usual size and a moderate proportion of window surface, this calculation can, in most cases, demonstrate that excessive heating of rooms due to solar irradiation is unlikely [8]. Residential buildings with a proportion of window surface of less than 30 % of their floor space and equipped with exterior shading devices do not have to provide verification of this effect. Such verification can often not be supplied by this method for residential buildings with a high proportion of glass or for non-residential buildings in particular. In these cases, it is advisable to carry out a more precise non-stationary thermal building simulation, which enables predictions of temperature variations in the space to be made based on a building’s properties, usage and

Passive solar energy use

Daylight factor [%]

A

B

C

D

E

25

D C

20

E

B

Standard office space in Stuttgart (D) (W ≈ D ≈ H: 4.00 ≈ 4.00 ≈ 2.50 m, open facade on one side)

15 A

10 5

3%

0

0

C 1.34 C 1.35

C 1.36

C 1.37

C 1.38

1.5

2

2.5

C

3 3.5 4 Distance to window [m] C 1.35

25 C

20 15 10

B

5

3%

A

0

0

1

1.5

2

2.5

A Daylight factor [%]

C 1.33

Area-specific heat energy required for a passive house depending on the proportion of windows in a south-facing facade, location and design. Calculations based on the Passive House Institute’s passive-house planning tool (Passivhaus-Projektierungspaket – PHPP). Parameters: (W ≈ D ≈ H: 8.50 ≈ 11.50 ≈ 6.00 m), average U value of opaque structural elements including thermal bridges is 0.11 W/m2K, window: Uw = 0.7 W/m2K, g = 0.5, 10 % window surface ratio on the northern, eastern and western sides, air exchange 0.4 h-1, heat recovery rate of 90 %. For heating through incoming air supply only, heat output is limited to 10 W/m2 (passive-house criterion). Cooling energy requirements for an office depending on its orientation with various window surface ratios. (Parameters as for Fig. C 1.31, p. 183; the example of a west-facing facade with passive cooling through overnight ventilation is also shown (West II); air exchange 48.8 l/s by day and 20 l/s at night) Connection between total energy, heating and cooling requirements and lighting Daylight factor, depending on the proportion of windows as a percentage (windows over the entire width of the space of 4 m) A: 20 % window surface B: 40 % window surface C: 60 % window surface D: 80 % window surface E: 100 % window surface Daylight factor, depending on the window’s parapet height (window 1 metre high over the entire width of the space of 4 m) A: 0.90 m parapet height B: 1.20 m parapet height C: 1.45 m parapet height Daylight factor depending on a window’s glass quality (window 1 metre high over the entire width of the space of 4 m) A: Single glazing, TL = 0.89 B: Double thermal insulation glazing with argon filling, TL = 0.8 C: Triple thermal insulation glazing with argon filling, TL = 0.68 D: Triple thermal insulation glazing with krypton filling, TL = 0.5 Daylight factor, depending on structural sun shading (window 1.40 metres high over the entire width of the space of 4 m) A: Brise-soleil, length 1.40 m, inclination 30° B: Projection 1.40 m long, 1:1 ratio to window C: Projection 0.70 m long, 1:2 ratio to window D: No projection

B

B

C

3 3.5 4 Distance to window [m] C 1.36

25 A 20

B C

15 D 10 5

D

3%

0

0

1

1.5

2

2.5

3 3.5 4 Distance to window [m] C 1.37

A B C D Daylight factor [%]

C 1.32

Daylight factor [%]

A

1

25

A

20 B 15 D 10

C

5

3%

0

0

1

1.5

2

2.5

3 3.5 4 Distance to window [m] C 1.38

185

Passive solar energy use

20 %

40%

60%

80%

100%

Type of daylight factor calculation for different configurations

Ø 1.9 %

Ø 4.5%

Ø 7.2%

Ø 8.7%

Ø 8.9%

Type of daylight factor calculation for different configurations with moveable sunscreens

Ø 1.0 %

Ø 2.6%

Ø 3.8%

Ø 4.0%

Ø 4.0%

Daylight factor [%] 1

2.5

3.5

5

7.5

10

12.5

15 C 1.39

chronological weather data with high temporal resolution. This is also advisable if innovative ventilation and shade concepts that a simpler process can model only inadequately are to be implemented. To comply with the DIN 4108-2 standard, it must be shown that a space is not subject to intolerably high or long-lasting excessive temperatures. This is done by calculating “excessive temperature hours”, multiplying excessive temperatures in Kelvin by their duration in hours per year. 1,200 Kh/p.a. is permitted for residential buildings and 500 Kh/p.a. for non-residential buildings, although the latter take only the usual occupancy hours (Monday to Friday, 7 am – 6 pm) into account. The underlying limit temperature depends on the building’s location in Germany and ranges from 25 to 27 °C.

and regulates essential bodily functions. Daylight also greatly influences performance. Good visual contact with the outside informs building users about their environment and weather, an effect that artificial lighting alone cannot provide. Appropriate daylight planning coordinated with summer and winter insulation requirements is indispensable in designing a building. A space’s daylight situation is calculated based on the “daylight factor”.

The influence of building openings on total energy requirements

It is measured without other buildings or shading under a completely cloudy sky. At 10,000 lux, a daylight factor of 1 % corresponds with an interior illuminance of 100 lux, for example. Since it is a ratio value, the daylight factor does not depend on the date, time of day and location and is ideally suited for making comparisons. The higher a daylight factor in a room, the better it will be illuminated with daylight. German workplace regulations (Arbeitsstättenrichtlinien) require office space to be illuminated with a daylight factor of at least 3 % in the middle of the room. This would supply a workstation with daylight for 50 to 70 % of the day on an annual average, thereby saving a significant amount of electricity required for artificial light. The daylight factor should not be much higher, to prevent glare in the workplace and overheating, especially in the summer. Whether a room is sufficiently evenly illuminated can be assessed by calculating the minimum and maximum daylight factors in a daylight simulation. This ratio value should be a maximum of 1:6 for lateral lighting through facade openings and a maximum of 1:2 for roof glazing. Daylight factor simulations and calculations are usually carried out based on the International Commission on Illumination (CIE)

As explained above, geometry, radiationphysics and the thermal properties of facade openings have various effects on a building’s total energy requirements. Modifying these properties may have partly contrary effects. While increasing the proportion of opening surface in a facade with the appropriate orientation can reduce a space’s heating energy requirements and electric lighting costs, it may also result in higher cooling energy requirements in summer (Fig. C 1.34, p. 184). In identifying an optimum proportion of opening surfaces, it should be noted that different energy sources supply various types of energy use (light and cooling is typically powered by electricity, heating generally by fossil or renewable fuels, perhaps with the support of solar power), each with their own different economic and energy issues. Depending on optimisation goals, the energy supplied must be multiplied depending on its price or primary energy factors.

Use of daylight Illuminating an interior with daylight is vital to the health and comfort of users. Natural light stimulates the human biological cycle

186

The daylight factor

The daylight factor D describes the percentage ratio of illuminance E at a point in an interior to illuminance outside. D=

Einterior · 100 Eexterior

standard. It defines a standard sky and mathematically models the sky’s spatial luminance distribution under various weather conditions. A room’s daylight factor is measured at about 0.85 metres above the floor (at about table height). Many factors influencing building openings also influence the daylight factor: • Proportion of opening surface area • Parapet and opening height • Depth of windows in an opening • Wall thickness • Geometry and surfaces of reveals, inside and out • Type and quality of glazing As well as the daylight factor, many other aspects influence the quality of daylight in a room, including • Reflectivity of walls, floors and ceilings • Evenness of the daylight factor in the depths of a space • Visual contact with the outside, depending on usage • Controllability of parameters influencing light quality (shading, artificial lighting) • Daylight autonomy • Light contrasts in the room The higher a window and the lower its lintel is, the deeper daylight penetrates into the room, so floor-to-ceiling glazing does little to improve interior illumination and is superfluous for the purposes of daylight planning. The wider the window is, the more evenly daylight will

C 1.39

Survey of the daylight factor for standard offices with various proportions of window surface, and a south-facing facade with a row of windows in Stuttgart (W ≈ D ≈ H: 6 ≈ 3 ≈ 4 m), double thermal insulation glazing, FC = 0.6 C 1.40 Links between daylight autonomy, daylight factor and electricity requirements C 1.41 Monthly daylight autonomy values for an office (requirement 500 lx) in Stuttgart (D) for different daylight coefficients C 1.42 Monthly daylight autonomy values for an office (requirement 500 lx) for different locations; daylight coefficient 3 %

Passive solar energy use

80

80

60

60

40

40

20

20

0

0 5

10

15

D 3%

D 5%

100 90 80 70 60

C 1.40

be distributed across its width. DIN 5034 prescribes a standard height for window openings in building shells of 1.30 metres, a parapet height of 0.90 metres and a total window width of at least 55 % of a room’s width to ensure good daylight illumination. These issues are discussed below based on the example of a conventional office space in Stuttgart with the dimensions (W ≈ D ≈ H) 4 ≈ 4 ≈ 2.5 m and a facade open on one side (Fig. C 1.35 – 38, p. 185). Figure C 1.35 (p. 185) shows the ratio of daylight factor to window surface. Increasing the proportion of window surface improves interior illumination, although it also changes the contrast between the space directly in front of a window and areas deeper in the space. The more window surface there is, the greater the contrast and the more uneven luminance distribution will be. Despite better interior illumination, this can cause undesirable glare. In administrative building construction, for example, a proportion of window surface of 60 to 65 % is recommended as a guideline. Figure C 1.36 (p. 185) shows daylight levels for parapets and openings at various heights, demonstrating that the higher the window, the better the illumination in a room’s depths is. In this case, the daylight factor directly in front of the window, however, is lower because the area is shaded by the window’s high position. The evenness of interior illumination also improves if openings are set high in the facade, although very high windows can limit visual contact with the outside. Figure C 1.37 (p. 185) compares glass of various qualities. Single glazing generally offers better interior illumination than sun-screening glazing. The better the protection from undesirable solar heat and the lower the total energy transmittance, the lower the glazing’s daylight transmittance will be. Figure C 1.38 (p. 185) evaluates other forms of structural solar protection in the form of a projection over a window (of various lengths) and a “brise-soleil”. A 1.40 metre-long projection makes the daylight illumination of a room much

Stuttgart (D)

Lisbon (P)

100 90 80 70 60

50

50

40

40

30

30

20

20

10

10

0

20 25 30 Daylight factor [%]

Oslo (N) Daylight autonomy [%]

100

Power requirement [%]

Daylight autonomy [%]

100

Daylight autonomy [%]

D 2%

Daylight autonomy Power requirement, artificial light

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec C 1.41

worse than it would be without it. The situation is improved by installing a brise-soleil with a light-permeable louvre structure, which also provides effective protection from undesirable incoming heat. Making solar protection structures half as long will greatly increase the daylight factor in an interior. Figure C 1.39 shows the results of a survey of daylight factors for varying proportions of window surface for a standard office space with a row of windows in its facade. Daylight autonomy

The daylight autonomy of buildings with concrete illuminance demands, such as office workstations, can be determined by means of the daylight factor for a specific point (Fig. C 1.40). This value measures a typical period of use in which lighting requirements are exclusively met by daylight as a percentage. The factor is used almost exclusively in the construction of administrative buildings and is based on the hours usually worked in them. Office buildings with an average daylight factor of 3 % have workstations with an annual average of approximately 50 % daylight autonomy. Seasonally fluctuating amounts of daylight mean that percentages vary greatly from month to month (Fig. C 1.41), the more so the further from the equator they are (Fig. C 1.42). Since no standards are set for illuminance in residential spaces, it is not possible to determine daylight autonomy for them. Lighting is adequate in a unilaterally illuminated dwelling if the daylight factor in the centre of the space and 1 metre in front of both side walls is at least 0.9 % on average [9]. Window surface and daylight autonomy are not linear in proportion to each other. When the proportion of glazed surfaces on the facade approaches 50 %, the positive effects on daylight autonomy decrease considerably. Furthermore, increasing the glazed proportion from 70 to 90 % does not significantly improve daylight quality. For residential buildings, a window surface of 20 to 30 % of a space’s floor space is necessary to ensure users’ basic needs for light and visual contact with the outside. DIN 5034 offers a simplified process for deter-

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec C 1.42

mining minimum window sizes for unilaterally illuminated residential spaces. Controlled light refraction

Using certain materials or components that deflect light into an interior can increase the amount and /or quality of useful daylight in it. The refracted light can be direct or diffuse. Frosted or textured glazing can help to evenly illuminate a room with diffuse light, but it transmits less daylight than clear panes of glass and increases the risk of glare. Whether glazing diffuses light is of no importance in calculating the daylight factor because simulations that comply with the CIE standard are based on a cloudy sky, in other words, on diffuse light. The lower transmittance reduces average daylight factors in the room. This positive effect is limited to direct light. Higher illuminance than with clear glass can be achieved at greater depths in the room here, although illuminance depends on date, time of day and location, so it is a less suitable base for comparison. A “light shelf” is a broad horizontal or sloping slat with a highly reflective surface that is attached to a facade exterior in the upper area of a window to reflect light into a room’s depth and more evenly distribute daylight (Fig. C 1.43, p. 188). An exterior blind can also function as a light shelf (Fig. C 1.44). Light shelves close to glazing also serve as shading elements because they are not usually transparent. For this reason, their use is normally only advisable for spaces deeper than 4 metres. There are many other lightrefracting systems, some of which dispense entirely with facade openings close to the room in deflecting daylight into an interior, such as “light pipes” or heliostats. Figure C 1.45 offers an overview of daylight systems for refracting diffuse light and Figure C 1.46 shows daylight systems for refracting direct light (p. 189). Tools for calculating the potential use of building openings for solar power

In recent years, effective simulation programmes for evaluating buildings’ thermal behaviour have become established in plan-

187

Passive solar energy use

Greater luminance at the zenith

60°

B: Reflector outside C: Controlled light deflection inside

View

A: No light shelf Less luminance on the horizon C 1.43

ning practice. Based on stored weather data and realistic information on intended usage, they can calculate the heat transport and storage processes in a building and allow precise estimates of the progression of temperatures in its interiors and the energy required for heating and cooling to be made. They do, however, require considerable time and effort for data input and high levels of expertise, so they should only be used for issues that cannot be dealt with by simpler means. In the early stages of planning, simple manual calculations are usually enough to evaluate a design’s energy standard. These calculations often focus on heating energy requirements. In comparing various design options, these can be identified precisely enough with stationary calculations, which replace conditions occurring in reality that change over time with average exterior and interior temperature values during the heating period. On this basis, heat loss through structural elements and ventilation is identified and offset with heat gains from solar irradiation and internal loads to calculate the building’s heating needs. The main solar irradiation parameters, such as shading devices or the properties of glass, are also averaged over the period under review. The potential exploitation of solar gains can be estimated by means of the utilisation factor η, described in the section on “Utilisation factor and window orientation” (p. 183). It is not necessary to take heat storage in structural elements into account, because such brief effects equalise over the reviewed period of several months. Until 2009 in Germany, such simplified calculations could be used to draw up the heating period energy balance necessary for the official certification of energy requirements for residential buildings. They have now been replaced by a more precise but more complex process and the standards they were based on withdrawn (DIN EN 832) or replaced by new versions (DIN V 4108-6:2003-06). Dynamic thermal simulations can be used to define energy properties more precisely. They calculate in brief periods (often hourly) all the relevant energy flows in a building and

188

A

B

accurately physically represent how structural elements absorb heat and release it into a space, so they can calculate energy demand values much more realistically than stationary calculations. In contrast to those calculations, dynamic thermal simulations make it possible to define momentary states, such as temperature sequences in a room and provide a valuable basis for planning insulation against summer heat because they represent maximum temperatures and periods for which a prescribed maximum temperature is exceeded in a space. They also enable planners to optimise heating and cooling system designs, as well as compare various control strategies, and make it easy to compare designs or structures because the different versions are based on a common basic model, with only specific components varied. Since all flows of energy must be realistically represented for each step, dynamic solar irradiation simulation demands a more precise knowledge of the properties of glazing and solar protection devices than stationary calculations. The shading effect of sunscreen elements and transmittance of light-permeable structural elements must be calculated anew for each separate period, taking the sun’s position and resulting angle of incidence of light into account. This requires the angledependent optical properties of materials and structural elements to be incorporated into the programme. While most products available on the market are included in simulation programmes in the form of material libraries, it may be necessary if using innovative solutions to measure their technical properties and incorporate them in the simulation model. Quasi-stationary calculations are something between simple manual calculations and precise simulations. Similar to stationary calculations, they are based on input data for a specific period but seek to achieve more precise results by using shorter periods (e.g. months down to hours) and iterative calculations. Examples of these are the processes described in DIN EN ISO 13 790 or calculations prescribed in DIN V 18 599 for the legally required certification of energy use in Ger-

C

C 1.44

many. These processes require similarly high levels of data input as dynamic simulations, but their results are not nearly as informative, and as such, are not recommended for optimising buildings’ energy usage. Notes: [1] Williams, David R.: Sun Fact Sheet. Greenbelt 2004. http://nssdc.gsfc.nasa.gov/planetary/factsheet/ sunfact.html (16.08.2010) [2] DIN EN 410 states that, “The parameters are measured for quasi-parallel, almost perpendicular incident radiation [...].”. See also Publication CIE No. 38 (TC-2.3): Radiometric and photometric characteristics of materials and their measurement (1977). The designation g⊥ is used in DIN V 18 599-2 and in the older DIN V 4108-6:2003 and DIN EN 832 [3] e.g. in DIN EN 12 464-1 “Lighting in workplaces – Indoor workplace lighting”, in the German workplace guidelines (Arbeitsstättenrichtlinen – ASR), and especially in ASR 7/3 “Artificial lighting” and in ASR 7/3 “Safety lighting”. [4] To precisely indicate a coating’s position in an insulating glazing unit, glass surfaces are always numbered from the outside in. Position 2 means, for example, that the side of the outer pane of glass that faces the interior is coated. [5] Herzog, Thomas; Krippner, Roland; Lang, Werner: Facade Construction Manual. Basel, 2004 summarises the topic of “Manipulators” in Chapter B 2.2, p. 259ff. [6] For more, see also Wagner, Andreas et al.: Energieeffiziente Fenster und Verglasungen. Stuttgart, 2013 [7] acc. to Passivhaus Institut, Darmstadt, see also http://passiv.de/de/02_informationen/01_wasistpassivhaus/01_wasistpassivhaus.htm [8] An overview of how the various main influential factors can affect insulation against summer heat and compliance with current legal requirements can be found in Maas, Anton; Kempkes, Christoph; Schlitzberger, Stephan: Summer heat insulation – new edition of DIN 4108-2. In Bauphysik 3/2013, p. 155 –161 [9] See DIN 5034-1:2011 “Light brightness in dwellings [...] is [...] adequate if the daylight factor on a horizontal reference level, measured at a height of 0.85 m above the floor halfway through the space and at a distance of 1 metre from both side walls is at least 0.9 % on average and at least 0.75 % at the least favourable of these points. In dwellings with windows in two adjacent walls, the daylight factor at the least favourable reference point must be at least 1 %.” C 1.43 C 1.44

Functioning of a light shelf Diagram of daylight factor depending on lightrefracting systems such as light shelves or blinds C 1.45 Systems for refracting diffuse daylight C 1.46 Systems for refracting direct daylight

Passive solar energy use

Diffuse light deflection Light shelf

Holographicoptical elements (HOE)

Sunscreen that admits diffuse light

Anidolic ceiling

Total ConcenLightPrismatic Pristration reflection matic panels with refracting with with panels aluminium shading HOE HOE louvres 60°

Protective functions

Sun screening

n. r.

n. r.

‡

‡

‡

‡

‡

Glare protection

n. r.

n. r.

‡

‡

‡

‡

‡

Views with lighting function

Views

‡

‡

‡

‡

‡

‡

‡

Deflection of light into the depths of the space

‡

‡

‡

‡

‡

¥

¥

Costeffectiveness Controllability Installation

Even light distribution

‡

‡

‡

‡

‡

‡

‡

‡

Changing the light spectrum

¥

‡

¥

‡

‡

¥

‡

‡

Saving on artificial light

‡

‡

‡

‡

‡

‡

‡

‡

Cleaning Maintenance

‡

‡

‡

‡

‡

‡

‡

‡

Auto tracking

¥

¥

¥

‡

‡

¥

‡

‡

Individual regulation

¥

¥

¥

‡

‡

‡

‡

‡

Whole opening area

Upper window area

Whole opening area

Whole opening area

Inside

Outside

Outside

Outside

Position in facade Installation position

‡ yes

‡ to some extent

Upper window area

Upper window area

Outside / inside

Outside

¥ no

Upper window area

Upper window area

Outside / Outside inside

n. r. not relevant

C 1.45

Direct light deflection

Protective function Views with lighting function

Cost effectiveness Controllability Installation

1

Depending on the sun’s position

Lasercut panel

Lightdeflecting glass

Light shelf

Pivoting louvres

Lightdeflecting blinds

Diffusion

CPC1 Glazing Lightwith mirror structures diffusion profiles systems

Sun screening

¥

¥

‡

‡

‡

‡

‡

‡

Glare protection

¥

‡

‡

‡

‡

‡

‡

¥

Views

‡

‡

‡

‡

‡

‡

‡

‡

Deflection of light into the depths of the space

‡

‡

‡

‡

‡

‡

‡

‡

Even light distribution

‡

‡

‡

‡

‡

‡

‡

‡

Changing the light spectrum

¥

¥

¥

¥

¥

¥

¥

¥

Saving on artificial light

‡

‡

‡

‡

‡

‡

‡

‡

Cleaning maintenance

¥

¥

‡

‡

‡

¥

¥

¥

Auto tracking

¥

¥

‡

‡

‡

¥

¥

¥

Individual regulation

¥

¥

‡

‡

‡

¥

¥

‡

Position in facade

Upper window area

Upper window area

Upper window area

Whole opening area

Whole opening area

Whole opening area

Whole opening area

Whole opening area

Installation position

Space Outside / Outside / Space inside between between inside the panes the panes

compound parabolic concentrator

‡ yes

‡ to some extent

Outside / space between the panes inside

Space Outside / Space space between between the panes the panes between the panes inside

¥ no

C 1.46

189

Active solar energy use Thomas Stark

C 2.1

Apart from a building envelope’s basic functions such as providing protection from weather, thermal insulation, lighting and ventilation, another function is becoming increasingly important: active energy generation. Current increasingly sophisticated energy strategies being applied in zero-energy or energy-plus houses lend themselves to the use of solar radiation on roofs and facades for actively supplying power, heat and cooling. This goal has so far mainly been implemented in technical solutions oriented towards efficiency, with standard solar technical components with no particular design concept installed on suitable building envelope surfaces. To further its development, solar technology will have to be incorporated into the building envelope’s design concept and functionality and the materials used included in the planning process. Only then will cogent architectural design concepts emerge that make use of multiple-application structural elements to achieve potential synergy effects and cost-effective solutions. Heat (air)

Solar technology is based mainly on the absorption of solar radiation and its conversion into heat or electricity. The elements required to do this are connected with each other and with the building’s internal technology by pipe and cabling infrastructure, making opaque, fixed elements especially suitable for solar activation of a building envelope. These types of surfaces are usually planned in the context of transparent or moveable elements and should be thoroughly integrated in the planning of building openings.

C 2.1 C 2.2

Microscopic image of microalgae Principles of active solar energy use in the building envelope a Solar air heating b Solar electricity generation c Solar water heating d Solar electricity generation and water heating e Radiation cooling at night f Solar water heating and biomass production C 2.3 Principle of the photothermic effect C 2.4 Functioning of a crystalline solar cell

Usage: direct use Heat pump

Heat (fluid)

Open absorber / flat-plate collector a

b Generates: electricity

Usage: direct use Storage Fed into the grid

Open absorber / flat-plate collector / evacuated-tube collector

Generates: heat (fluid) Electricity

PVT collector

Crystalline PV / thin-film PV c

Usage: direct use Storage Heat pump Cooling Direct use Storage Fed into the grid

d Generates: cool water

Usage: direct use Storage

Generates: heat (fluid)

Usage: direct use Storage Heat pump

Biomass

Biogas Fuel CHP

Biomass reactor

Open absorber / PVT collector e

Usage: direct use Storage Cooling

f C 2.2

190

Active solar energy use

Principles of active solar energy conversion All buildings use solar energy in some form. Irradiation on structural elements is converted mainly into heat, while solar radiation passively penetrates transparent elements and heats a building’s interior. This energy input can be controlled only to a certain extent and is taken into account in the energy calculations used to determine a building’s thermal balance (see “Passive solar energy use”, p. 170ff.). In contrast to passive solar energy use, active solar energy use aims to exploit solar radiation as far as possible. Figure C 2.2 shows the various design concepts of common systems. After absorption through the building envelope, the energy is harnessed by storage and control technologies that make it possible to better coordinate energy supply and demand. Such systems can be differentiated in accordance with the form of energy the building envelope supplies: solar heat, solar power and solar produced biomass, which is still at the experimental stage. Solar heat generation

Solar heat generation is also called solar thermal energy (from the Greek “sol”: sun, “thermos”: warm). Its principle is based on the fact that short-wave solar radiation is converted into long-wave thermal radiation when it strikes a material (Fig. C 2.3). Technical system components, consisting of a collector array, a circuit with a heat transfer medium and usually storage, are assembled to make effective, controlled use of this radiation. Combined with control technology, these components regulate heat flows and allow useful quantities of heat to be largely chronologically decoupled from solar radiation. Solar thermal plants produce emissions only in the manufacture of components and the power pumps or ventilators required for heat transport (auxiliary energy). The system’s central element is an absorber, typically a special highly absorbent copper or aluminium plate. To utilise the energy generated, a transport system diverts the heat. It can then be used in the building for heating, household water heating and for thermally driven cooling processes or operating ventilation equipment. Other system components vary depending on the type of heat transfer medium (fluid or air). Fluid as a heat transfer medium Most solar thermal systems work with a fluid medium such as water, air, or in climatic zones with frost seasons usually a mix of water and glycol. Absorber elements are connected at the back to a pipe system that functions as a heat exchanger. The absorbed solar radiation is transferred through heat conduction to the fluid and diverted. In a plant room, another heat exchanger releases the heat into storage. Water has a very high heat storage capacity, so its temperature can remain high for long periods in well-insulated storage tanks.

Depending on the system design, this can range from a few hours up to several months (seasonal storage). Air as a heat transfer medium As well as fluids, air can be used to draw heat from the absorber. This can be advisable if air is used to distribute heat in a building (e.g. air heating) or the updraft of warm air is to power ventilation systems (e.g. in a solar chimney). In this case, absorbers have a direct intake of warm exterior air at the back, with the heat diverted into a ventilation system or directly into an interior. Storing warm air is not generally advisable, because the heat storage capacity of air is low and a very large volume would be required. Solar heated air can be used to heat mass storage units (e.g. gravel storage), but these systems are usually only active when there is adequate solar radiation and a simultaneous need for heating.

ing. This is especially important for networked energy concepts, such as those designed to meet the needs of large building complexes or of mobility for an entire urban district.

Solar structural element technologies and their design potential Active use of solar radiation always involves using technology (Fig. C 2.6, p. 192). Energy conversion components are particularly important in planning because they are exposed to solar radiation and usually visible. Developers of future applications are therefore focusing on the structural and design integration of solar conversion systems into building envelopes. Currently available solar heat production and photovoltaic power generation technologies are explained below, and biomass production in the facade, which exists in the form of a prototype, is also described.

Solar power generation

Photovoltaic systems are another way of making active use of solar radiation. Based on the photoelectric effect, they can generate power through the building envelope without mechanical attrition or causing air or noise emissions in operation. The photoelectric effect is the transfer of energy contained in the photons of sunlight to electrons in the semiconductor material. The central element in such systems is the photovoltaic or solar cell (Fig. C 2.4). When solar cells are integrated into an electrical circuit, electrical energy flows as soon as light hits the surface. Solar cells are divided into various categories and referred to by their structure and basic materials. One material suitable for solar cells is silicon (Si). Most cells used today are made of it.

Open absorbers

Solar biomass production

Electron is excited by light energy

A third kind of solar energy use in building envelopes is biomass production, a technique that is still in the development phase. Its idea is drawn from the biogas production widespread in agriculture. Microalgae are cultured in special facade elements by adding carbon dioxide and nutrients. The elements are connected with each other and with a technical centre. Carbon dioxide circulates permanently through the system, transferring heat from the facade into a plant room like an ordinary solar thermal system. Cell division means that new algae constantly grow in the facade elements. They are transferred to the plant room, where a conversion plant converts them into biogas, which can be used in a fuel cell or combined heat and power generation unit to produce heat and power locally (Fig. C 2.5, p. 192). Alternatively, the gas can be sent to a gas filling station or fed into the gas supply network. Fluid fuels (e.g. alcohol, biodiesel) can also be produced using this principle. Producing gaseous or fluid energy sources makes the energy easy to store and use outside the build-

Solar thermal elements without glass covers are called open absorbers. They can either be metal facade or roof elements that air flows through the back of or components with a heat exchanger for a fluid medium (Fig. C 2.7 a, p. 193). The simplest form of this technique is black plastic pipes installed directly on a building envelope. Another option is the use of translucent plastic panels through which outside air flows. Their open construction means that high levels of heat loss occur when they are operated at low exterior temperatures, so they produce only a low temperature as net energy. Collectors are therefore usually combined with a heat pump system to produce the

–

+

– Excited electron leaps up to a higher energy level

Excited electron returns to its path with a lower energy level and emits thermal energy

–

+

–

–

–

+

C 2.3 –

Front contact P/N transition Rear contact

+ N zone (negative) P zone (positive) C 2.4

191

Active solar energy use

Biomass

Bioreactor facade

CO2 Heating Biogas

Fuel cell

Power station Hot water

Electricity Biomass / biogas Electrical power

District heating

Heat CO2

C 2.5

temperatures required for building services. Their structural and design possibilities vary greatly depending on the material used. Flat-plate collectors

Flat-plate collectors through which water flows are the most common type of collector. To minimise convective losses from the absorber into the environment, they are usually expanded to form boxy elements with special solar glass covers on the side facing the sun and are insulated on the back (Fig. C 2.7 a). A heat transfer medium flows through the absorber and diverts the useful heat. Flat-plate collectors are produced mainly as standard Energy benefits

products with fixed dimensions and technical specifications. Only a few manufacturers offer individual solutions. Such special formats can be largely prefabricated and are available in sizes up to 30 m2. Flat plate collectors as planar structural elements with glass covers are very suitable for integration into facades or roofs. Collector formats and their horizontal and vertical layout can be individually adapted to the building’s design grid. The colour of the absorbers and the optical characteristics of their glass covers can be varied. To increase efficiency, covers are usually made of highly transparent glass, so their appearance is dominated by the absorber beneath. If this is not Technology

Open absorber

desired, treated (structured or coloured) glass can be used. Air solar heater collectors can be integrated to generate power from heated air. In their structure and integration into the building envelope, they are similar to flat-plate collectors C 2.5 C 2.6 C 2.7

C 2.8 C 2.9

Principle of generating energy through a bioreactor facade Principles and technologies for active solar energy use in the building envelope Various types of collectors a Flat-plate collector b Evacuated-tube collector Crystalline solar cells in laminated glass Thin-film solar cells in laminated glass

Planning notes Usually activated metal elements or vacant PE pipes Low temperature Combination with a heat pump

Flat plate collector

Usually housed in a flat glass cover Can be integrated into a thermal envelope High temperature for heating and domestic water supply heating Can be transparent Direct air heating possible

Vacuum tubes

Glass tubes with spacing Can be used as solar protection High temperature for heating and domestic water supply heating

Solar heat

Active solar energy use in the building envelope

Solar power

Biomass

Hybrid collectors (PVT)

Usually laminated glass or insulating glass structure Can be transparent

Crystalline modules

Usually laminated glass or insulating glass structure Can be transparent

Thin-film modules

Usually laminated glass or insulating glass structure Flexible modules on foil possible Can be transparent

Microalgae reactor

Heat and biogas production Laminated glass structure Still in the research phase C 2.6

192

Active solar energy use

a

through which water flows, but the absorber is a flat shaft structure into which outside air flows and openings required for the air intake must be taken into account. Flat-plate collectors usually come in sizes of approx. 1 ≈ 2 m. Depending on their technology, allowances may also have to be made for restrictions in their angle of inclination because of their hydraulic connections. Evacuated-tube collectors

An absorber can be enclosed in a vacuum (thermos flask principle) to minimise heat losses in a collector. For reasons of stability, glass tubes 40 to 100 mm in diameter and 1.50 to 3.00 m long have proven their efficacy for this purpose. The tubes contain stripshaped or tubular absorbers through which a fluid heat transfer medium flows (Fig. C 2.7 b), similar to a flat-plate collector. The distribution line is on one side of the tubes. Integration of evacuated-tube collectors into the structure and design of building envelopes is not yet widespread. They have a high aesthetic potential, but their geometric and individual design options are quite limited. “Heat pipe” technology uses a working fluid that circulates inside the tubes and evaporates, thereby using convection to release energy into a distribution pipe. Potential restrictions in their angle of inclination must be taken into account in integrating them into facades (horizontal installation is impossible). Appropriately installed evacuated-tube collectors without a reflective element on the back are suitable for use as fixed sunscreen elements and can also be installed in the parapet area. Crystalline photovoltaic modules

Crystalline solar cells, most often in a 150 ≈ 150 mm format, are electrically connected and deposited as individual elements on a glass substratum, then joined with transparent adhesive foils under pressure and at a high temperature to form a weatherproof module. These photovoltaic modules are primarily designed to protect solar cells from the weather and to simplify installation. They are usually available as laminated glass or glass-foil elements, so they can be used like glazing elements (Fig. C 2.8).

Various special modules are available for particular applications (e.g. solar roof tiles, solar membranes etc.). Almost all ordinary flat glass elements can be given a photovoltaic function and used to generate power through a building envelope. Standardised yet sophisticated photovoltaic modules are available in a wide range of formats, and a few companies also make customised, site-specific elements. As well as blue and black, which provide optimum gains, various anti-reflection coatings can be added to crystalline solar cells to produce other colours. Thin-film photovoltaic modules

Thin-film technology developed in the 1970s with amorphous silicon solar cells. As semiconductor material is applied directly onto a glass, metal or plastic backing layer, it is possible to save considerable amounts of material and energy in their manufacture as well as give them a homogeneous appearance (Fig. C 2.9). Thin-film technology allows cells of any size or shape; the only limits are the dimensions of the backing material and desired electrical properties. Their colour, however, depends on the cell material and is fairly fixed. Flexible photovoltaic modules can be made by depositing this type of cell on metal or plastic foils. One current development in facade technology is the integration of narrow strips of thin-film solar cells into the space between windowpanes, which offers good technical values and high levels of transparency (Fig. C 2.10, p. 194). Wide-ranging developments involving organic solar cells are currently being made in the field of thin-film technology, and there is potential for creating other colours and optimising costs in the production of nearly transparent modules (Fig. C 2.11, p. 194).

b

C 2.7

C 2.8

Hybrid collectors (PVT)

Systems designed for generating both solar power and thermal energy are called hybrid or PVT (photovoltaic thermal hybrid) collectors. Crystalline or thin-film photovoltaic elements form the outer layer, behind which thermal absorption (using a fluid or air) occurs. Hybrid collectors are a relatively recent development and not yet of major importance in the market. C 2.9

193

Active solar energy use

A wide variety of these technologies is available, ranging in form from two systems installed one above the other through to specially manufactured standard products (Fig. C 2.12). The structural and design conditions they require are similar to those for individual photovoltaic and solar thermal components. Bioreactor elements

C 2.10

The bioreactor facade is still a very recent development and has been created for the first time on a large scale in a pilot project in Hamburg (Fig. C 2.13). This facade’s energy convertors are the first prototype bioreactors for integration into a building and consist of an aluminium frame that holds two panes of glass separated by a spacer profile. The element, 2.60 ≈ 0.70 metres in size, is only 20 mm thick and has a volume of about 24 l. The space between the panes is filled with a fluid medium rich in nutrient salts in which algae grow. An inlet pipe and drainpipe connect the modules to a circulating system. Compressed air keeps the medium in constant movement, which in the current prototypes can cause audible noise. Integrating such a system into a building envelope would involve costly and complex installation. On the other hand, bioreactor elements could be made in a very wide range of sizes and formats. The potential of their structural and design possibilities has not been conclusively investigated so far.

C 2.11

Efficiency and profitability

C 2.12

The efficiency of solar systems integrated into buildings depends on a number of factors. Based on the solar constant in the universe, the effective annual level of solar radiation on a specific building envelope depends on its location, orientation and shade situation. This represents the solar system’s maximal utilisable potential. How much solar radiation a building envelope can convert into energy depends on the efficiency of the technology used. This is in turn product-specific, not constant, and can depend on other factors, such as system temperatures. The maximum specific collector yield per square metre ranges from less than Balance sheet item

300 to over 600 kWh a year for thermal systems, while it is less than 50 to over 150 kWh for photovoltaic plants. It must be noted that these systems work with different forms of energy: heat and power. A heat pump, for example, can generate up to 4 kWh of heat from 1 kWh of power. In identifying levels of actual utilisable energy, it is important to establish how well energy needs correspond with solar gains over the course of the day and year, because energy that is not directly used requires some form of storage, which results in further losses. It is not unusual for up to half the energy generated by collectors in thermal systems to be unavailable for operating a building due to storage losses. The possibility of feeding electricity into the public power grid means that all the energy photovoltaic plants generate can usually be used, if not in the building itself. As well as optimising the demand structure, the directly used proportion of power can be increased by distributed power storage. Since using the power you generate yourself is usually financially more attractive than feeding power into a public grid, this can have a very positive effect, although the efficiency of storage and additional costs must be taken into account. The profitability of a solar system integrated into a building involves complex issues that need to be differentiated. Profitability is the ratio of cost to benefit (Fig. C 2.14) and, in this case, the cost is mainly the investment in a solar system, whose operating costs will be very low. Collectors and photovoltaic modules are generally the largest items on the system costs balance sheet. Solutions integrated into the building envelope reduce the costs of an alternative roof or facade structure, although higher costs for auxiliary energy and servicing and maintaining the solar system are incurred. The system’s main benefit is the energy generated: directly usable energy, which saves heating or power costs, as well as a possible energy surplus. Depending on the concept, this power can be sold and fed into a power or local heat network for external use and remunerated as such. Alternatively, it can be stored locally, although here a comparison of the costs and benefits of storage

Economic evaluation

Investment costs

Added costs compared with alternative building envelope solution

Operating costs

Costs for auxiliary energy, servicing and maintenance Added costs compared with alternative building envelope solution

Cost

Directly usable energy

Saving of energy procurement costs

Benefit Energy surplus C 2.13

194

Local storage: expense and efficiency of storage solution Feed-in: revenue from the sale of energy C 2.14

Active solar energy use

Technology

Medium

Direct use

Application

Construction

Design

Revenues /costs

Open absorber

Fluid

Heating Cooling

Heating water to low temperatures, used in heating pools or as energy source for heat pumps or cooling element for radiation cooling

Integrated into buildings usually as metal roof or facade elements with a heat exchanger on the back; mainly ordinary structural elements with an extra solar-active function, hydraulic connection with supply and return pipes

Look like conventional surfaces; can be any colour and structure; efficiency depends on surface coating; dark surfaces are more absorbent

Typical efficiency 40 %, typical top operating temperature 40 °C. Structural elements cost up to 100% more than comparable passive elements, plus installation costs

Air

Heat

For heating air; used for heating in ventilation systems or as energy source for heat pump

Most use ordinary rear-ventilated metal facade elements with slight modification for air intake and outlet areas

Fluid

Heat

Heating of water to high temperatures, used for domestic water supply heating, heating, or driving heat for cooling processes

Standard boxy element with a flat glass front and insulation integrated into the back. Typical size; width 100 –140 cm, height 140 – 220 cm, depth 6 –10 cm, hydraulic connection with supply and return pipes

Air

Heat

For heating air, used for heating in ventilation systems or as energy source for heat pumps

Evacuatedtube collector

Fluid

Heat

Heating of water to high temperatures; used for heating domestic water supply, heating, or driving heat for cooling processes

Typical for standard element: 10 – 20 pipes, width 140 – 220 cm, length 140 – 200 cm, pipe diameter 50 –100 mm, pipe spacing 50 mm, distribution line attached on one side. Usually installed on metal frames, hydraulic connection with supply and return pipes

Glass tubes with visible, usually dark blue absorber elements; pipes available in lengths 100 – 300 cm, with a reflector element on the back or some partially transparent

Typical efficiency 80 %, typical top operating temperature 90 °C. Standard structural elements cost approx. €200 – 350 /m2, plus installation costs

Crystalline PV module

Electrical connection

Power

Solar cells generate power and can be used in the building or the energy fed in to the public power grid

Typical standard element: width 80 –120 cm, length 140 –180 cm, thickness 4 – 8 mm, with metal frame 40 – 50 mm. Usually installed on metal frames or clamp systems like laminated glass, electrical connection

Glass surface, can have an antireflection coating or structuring, appearance depends on cell type, size, colour, position and rear side; all features variable, incl. size, format, transparency and rear coating structure (e.g. insulating glazing)

Typical efficiency 15 – 20 %. Standard structural elements cost approx. €100 –150 /m2, plus installation costs. Customising may entail high extra costs

Thin-film PV module

Electrical connection

Power

Solar cells generate power that can be used in the building or fed into the public power grid

Typical standard element: width 60 cm, length 120 cm, thickness 8 –10 mm, usually mounted with a clamp system like laminated glass, electrical connection

Glass surface, anti-reflection coating or structuring possible; homogeneous cell surface determines appearance, cell colour depends on cell material; size, format, transparency and rear coating structure variable (e.g. insulating glazing)

Typical efficiency 5 –12 %. Standard structural elements cost approx. €70 –100 /m2, plus added installation costs. Customising may entail high extra costs

PVT collector

Power Electrical connection, heat cooling fluid

Simultaneous production of power and heating of water; usage, see above

Typical standard element: width 80 –120 cm, length 140 –180 cm, thickness 40 – 80 mm. Usually mounted on metal frames or clamp systems like laminated glass, electrical and hydraulic connections

Glass surface, anti-reflection coating or structuring possible; appearance depends on cell type, size, colour, position and rear side. All features variable incl. size and format. Back side open or insulated.

Typical efficiency 15 – 20 % electrical and 60 – 80% thermal. Standard structural elements cost approx. €400 – 600/m2, plus installation costs. Customising may entail high extra costs

Bioreactor element

Fluid

Production of heat and algae by a circulating nutrient salt solution; can be further processed into biogas and biooil

Prototype: Glass-glass element with aluminium frame: width 70 cm, height 260 cm, thickness 2 cm

Prototype: translucent, greenish fluid

Prototype status, no specific values available

Flat-plate collector

Heat, biomass, biogas, biooil

C 2.10 Transparent glass facade modules with integrated louvre system in the space between the panes for solar climate control in rooms, electricity generation from solar cells and light refracted into the depths of the room. The element achieves a U-value of < 0.05 W/m2K and electrical output

Typical efficiency 40 %, typical top operating temperature 40 °C. Structural elements cost slightly more than similar passive elements, plus installation costs

Front glass can be clear or translucent; absorber usually dark blue to black with adaptation possible; individually adaptable dimensions; can be completely integrated into the building envelope

Typical efficiency 70 %, typical top operating temperature 70 °C. Structural elements for standard products cost approx. €150 – 250 /m2, plus installation costs. Customising may entail high extra costs Typical efficiency 60 %, typical top operating temperature 50 °C. Standard structural elements cost approx. €250 – 350 /m2, plus installation costs. Customising may entail high extra costs

of 86 Wp/m2, Stuttgart (D) 2015, Solsixy, Odilo Reutter C 2.11 Photovoltaic module with highly transparent organic solar cells integrated into laminated glass (visualisation) C 2.12 Structure of a hybrid collector

C 2.15 BIQ – Passive house with a bioreactor facade, Hamburg (D) 2013, SPLITTERWERK, Arup Deutschland, Bollinger + Grohmann Ingenieure, Immosolar, Strategic Science Consult C 2.14 Profitability of solar systems integrated into buildings C 2.15 Overview of the main planning aspects C 2.13

195

Active solar energy use

Position

Transparent

In the opening

Opaque

Solar thermal

Photovoltaic

‡

‡

Protection from weather, thermal separation, solar protection, ventilation

‡

‡

‡

Protection from weather, perhaps ventilation

‡

‡

Solar protection, possibly safety barrier

‡

Solar protection

‡

Next to the opening In front of / above the opening, fixed

‡

‡

In front of / above the opening, moveable

‡

‡

‡ Expedient

Multiple benefits of solar technology

‡ Possible

C 2.16

technology must be made. So far, it has become clear that a short-term approach to solar systems will not produce a profitable result. In most cases, investment costs are redeemed within 10 or more years. Photovoltaic systems usually achieve even better figures. The extra cost of customised collectors or photovoltaic modules for systems integrated into buildings can be much higher than the costs of standard products. Optimum profitability can be achieved if conventional materials can be replaced with standard solar system elements.

Active solar technology combined with opening elements Collectors and modules are designed for use outside and weatherproof, so it would seem advisable not to add them to a building envelope but to use them as an alternative to the usual materials so that the elements can take on multiple building envelope functions that will improve profitability. This approach also improves the framework for integrating solar systems into high-quality architectural designs. In practice, planners must differenti-

C 2.17

ate between standard components and systems designed for specific projects. Standard products currently make up about 95 % of the market and have fixed dimensions, design and technical data, so they are harder to integrate into architecture. All solar technical components can be individually manufactured and their size, format, material, surface, colour or technical parameters more or less varied (Fig. C 2.18). Such an approach is expedient in integrating solar systems into a building envelope’s structure and design but may involve considerable extra costs compared with standard components. A precise estimate of extra costs compared with an inactive solar system is especially required when planning individually developed solar components that fulfil other building envelope functions besides energy generation. Figure C 2.15 (p. 195) provides an overview of the most important planning aspects for integrating solar systems into architecture. Four fundamental structural principles apply when integrating solar thermal collectors and photovoltaic modules into building openings (Fig. C 2.16): direct integration in the opening element as laminated or insulating glazing, installation on the same level, but at the sides next to opening elements, and installation at the same level or in front of or above an opening. Solar components installed above openings can be fixed or moveable elements. Depending on their functional principle, other issues involving transparency, type of solar technology and achievable multiple functions in the building envelope may arise. Collectors or photovoltaic modules installed in the form of insulating glass elements can be integrated directly into ordinary glazing systems. Translucent elements provide thermal separation as well as a supply of daylight. Figure C 2.17 shows an example with crystalline photovoltaic elements in fixed glazing. Elements can be integrated into opening casement windows, with electrical connections between the window frames and sashes made using ordinary solutions. Solar thermal sys-

C 2.18

196

Active solar energy use

C 2.19

tems can be more difficult to connect, as two, usually insulated pipes up to 100 mm in diameter must be taken into account. Such systems have been so far only installed in fixed glazing. Systems can also be integrated into roofs, where elements can be installed in ceiling glazing. Translucent solar horizontal glazing can also function as openable elements for ventilation or as smoke outlets.

C 2.20

Opaque solar systems make very good replacements for classic roof or facade elements. Special installation systems make it possible to integrate skylights flush with a roof (Fig. C 2.19) in a way similar to solar thermal flat-plate collectors (Fig. C 2.20). Elements can also be usefully integrated into a facade by alternating them with opening elements. Photovoltaic modules form the outer layer and protect against the weather. Since the backs of the elements are insulated anyway, solar thermal plants can also take on extra thermal functions (Fig. C 2.22). Both systems could, in principle, also be used in structures that function as ventilation vents.

Many other integration options could be gained by detaching from the thermal envelope and integrating in a layer in front of or above opening elements. Typical multiple functions are sun screening or safety barriers. Vacuum-tube collectors are also an interesting multifunctional alternative. They can be usefully integrated into vertical and horizontal glazing and opening elements and provide shade while allowing views between the tubes (Fig. C 2.21). Planar systems such as photovoltaic modules or solar thermal flat-plate collectors (Fig. C 2.23), which are usually translucent, could also be used in this way. Solar elements in an additive layer can be installed as moveable systems. Figure C 2.24 shows custom-made crystalline photovoltaic modules as large-format sliding shutters in front of a window opening. Electrical contacts for the photovoltaic elements can be provided through the installation system. Solar thermal systems are much harder to integrate because of their more complex pipe systems, so their application here would be quite limited.

C 2.22

C 2.23

C 2.21 C 2.16 C 2.17

C 2.18

C 2.19 C 2.20 C 2.21

C 2.22

C 2.23

C 2.24

Position of solar technology relative to the building opening Translucent crystalline photovoltaic modules integrated into a non-ventilated facade, SMA Solar Academy, Niestetal (D) 2010, HHS Planer + Architekten Thin-film dye-sensitised solar cells are translucent, function regardless of the light’s angle of incidence and offer protection from direct solar radiation. SwissTech Convention Center, EPFL, Lausanne (CH) 2012, Richter Dahl Rocha & Associés Architectes Crystalline photovoltaic module combined with a flat roof window Solar thermal flat-plate collectors combined with a roof window Evacuated-tube collectors above horizontal glazing, home+, Solar Decathlon 2010, Stuttgart University of Applied Sciences (Hochschule für Technik) Facade-integrated flat-plate collectors alternating with window surfaces and roof-integrated photovoltaic elements, apartment house, Bennau (CH) 2009, grab architekten Transparent solar thermal flat-plate collectors in front of a glass facade, council housing, Paris (F) 2010, Philippon + Kalt Architectes Moveable sliding shutters made of crystalline photovoltaic modules, house, Pratteln (CH) 2003, Reto Miloni

C 2.24

197

Technical building components in and around windows Markus Binder

C 3.1

As well as supplying interiors with light and fresh air, one of the primary functions of windows and facade openings is to let moisture and pollutants out. As construction methods become more technologically advanced, building services are increasingly supporting or even completely fulfilling these functions to more specifically achieve the desired interior conditions and save energy. From a functional perspective, various elements of building services do not necessarily have to be directly connected with windows, but such combinations are often advantageous. Combining functions can significantly minimise the need to create openings in a facade, which are always costly and complex to construct. Appropriately arranged heating elements and proper ventilation can compensate for comfort problems resulting from the typically lower levels of thermal insulation offered by windows and glazing compared with opaque facade elements. Lights integrated into facades can supplement the daylight entering through windows if required, while window-integrated sensors and actuators can help optimise building operations by linking them with building automation systems.

Ventilation and air conditioning A minimum exchange of air is required to ensure healthy, hygienic conditions in buildings and is traditionally provided actively by the opening of windows and passively through leaks in the building envelope (see “Permeability to air, joint permeability and minimum air exchange rates”, p. 61ff.). The driving forces behind air exchange are differences in temperature between the interior and exterior and wind pressure on facade surfaces. Since these factors depend on weather conditions, users have only a very limited influence over the exchange of air. High rates of air exchange can occur through joints in older, leaky buildings and cause heat losses and uncomfortable draughts in winter. For these reasons, buildings are now built to be airtight, so the necessary exchange of air must be ensured in other ways.

198

Required supply of fresh air

The volume flow required to supply a space with fresh outside air and release moisture, noxious and malodorous substances depends mainly on the number of people present and their activities. If physical activity levels are low, a supply of fresh air per person of 20 to 30 m3/h can be assumed. Much larger amounts of air may be required to prevent overheating if heat is also released through ventilation. Conversely, a reduced air exchange rate is sufficient outside of utilisation periods if only substances released by structural elements and equipment must be discharged. DIN 1946-6 prescribes air exchange rates for housing (see “Permeability to air, joint permeability and minimum air exchange rates”, p. 61ff.). As well as natural ventilation through window openings, which depends entirely on users, integrating ventilation components into windows is another way of ensuring a continuous supply of fresh air that meets users’ needs. Passive air vents are openings deliberately made in new buildings in and around windows, through which air can flow in or out and contribute to the required exchange of air. Built-in ventilators in active, windowintegrated ventilation devices manage volume flows and can also heat or cool incoming air. The options available depend on where ventilators are installed. Figure C 3.2 provides an overview. Guidelines LU-01/1 and LU-02/1 published by the ift Rosenheim specify the properties of and recommendations for air vents in and around windows.

C 3.1

C 3.2 C 3.3 C 3.4 C 3.5 C 3.6

Facade with integrated ventilation elements, Children’s and Cardiological Centre at the University of Innsbruck (A) 2008, Nickl & Partner Classification of air vents Soundproofed air vent for installation on a window frame, exterior view Integration of exterior air vents Self-regulating damper, correlation between wind pressure and volume flow Filter classes for ventilation technology in accordance with EN 779

Technical building components in and around windows

Passive air vent

Unregulated / manually adjustable

Active air vent

Pressurecontrolled

Moisturecontrolled

Without heat recovery

Without secondary heating /cooling

With heat recovery

With conditioning (two-pipe)

With conditioning (four-pipe)

C 3.2

C 3.3 Passive air vents

Window rebate

Glass rebate

Blind frame

Lintel / reveal Roller blind housing

Blind cover

Parapet

Volume flow [m3/h/m]

C 3.4

400

Self-regulating

Not self-regulating

350 300 250 200

Purely passive opening elements regulate airflows mainly by mechanical means depending on the difference in pressure caused by the wind or exhaust air systems or on the humidity in the space. Many manufacturers produce air vents that can be integrated into windows in various ways. The least conspicuous solutions are rebate vents, which are installed between the window frame and sash frame. Air vents can be installed in the window’s glass rebate and frame, and solutions are also available for installing them in the window reveal or parapet, in roller shutter boxes or behind blind housings. It is easier to inconspicuously integrate air vents into a facade by incorporating them into a window structure (Figs. C 3.3 and C 3.4) rather than positioning them in openings in walls, which is also often done. Most air vents have simple flaps that close in a strong wind. This prevents airflows that are too high, for example through leaky joints, and the resulting heat losses (Fig. C 3.5).

150 100 50 0 0

10

20

30

40

50

Self-regulating damper

60

70

80 90 100 Air pressure [Pa] C 3.5

Particle size

Coarse dust 100 – 2,000 µm

Pollen 10 –100 µm

Smoke, soot

Tobacco smoke 0.01–1 µm

G1

‡

¥

¥

¥

G2

‡

¥

¥

¥

G3

‡

‡

¥

¥

G4

‡

‡

¥

¥

M5

‡

‡

‡

¥

M6

‡

‡

‡

¥

F7

‡

‡

‡

‡

F8

‡

‡

‡

‡

F9

‡

‡

‡

‡

‡ Effective

‡ Somewhat effective

¥ Ineffective

Many air vents can be manually regulated and closed completely if no exchange of air is desired. Some models can be equipped with filters to keep out dust, pollen or other contaminants (Fig. C 3.6). Coarse filters in classes G2 – G4 as specified in DIN EN 779 are commonly used. Finer filters in classes M5 – F7 greatly reduce air throughput, so they are mainly used in air vents integrated into walls, because they have larger openings than vents built directly into windows. Air vents, like all openings in exterior walls, are acoustic weak points, but that should not mean that the wall fails to meet the sound insulation requirements against exterior noise as prescribed in the DIN 4109 series of standards. The sound reduction index R'W, res of the entire exterior facade, including windows and air vents, is decisive in this context. To improve sound insulation, some air vents are clad with mineral fibre or acoustic foam insulation. Since the insulation takes up space, improving sound insulation usually also involves increasing the size of the vent’s

C 3.6

199

Technical building components in and around windows

Ventilation concept

Applicable differential pressure Δp acc. to DIN 1946-6

Volume flow [m3/h] Rebate vent length approx. 25 cm

Air vent above the blind frame; height, approx. 6 cm; length, approx. 40 cm; without /with soundproofing

Mounted vent, moisture regulated, length approx. 40 cm

Sliding louvred vent, manually adjustable, height approx. 14 cm, length approx. 40 cm

Cross ventilation, single-storey unit, not a windy location

2 Pa

3

8 /2.5

1 ... 16

27

Cross ventilation, single-storey unit, windy location

4 Pa

4

12 /3.5

1.5 ... 23

38

Exhaust ventilator

8 Pa

5

17/5

3 ... 33

54

Amount of air transported [m3/h (10 Pa)]

C 3.7

60 50 40 30 20 10 0 0

10

20

30

40

50

60 70 80 90 100 Relative humidity [%] C 3.8

C 3.9

housing or, if it needs to stay the same size, a reduction in its open cross section and an increase in its flow resistance, which results in lower volume flows. Achievable volume flows given specific pressure differences is the most important criterion in selecting vents, followed by options for integrating them into the building design. The different types vary greatly. There can be a ten-fold difference in the volume flows offered by inconspicuous rebate vents and large-format air vents. Very compact solutions offering minimal ventilation are suitable for preventing damage from damp, while other types can deliver the complete required air exchange, depending on usage. Figure C 3.7 provides an overview of typical parameters. DIN EN 13 142 stipulates that manufacturers must identify and declare these performance parameters. Selecting components that will fit in with the building’s design and chosen ventilation concept is an essential task for planners. Humidity-sensitive air vents are a special form (Fig. C 3.9). They function based on the fact that the volume flow required for hygiene is not a constant but depends on the current humidity in a space. For this purpose, these air vents contain simple hygromechanical sensors that regulate the vent flap’s opening width depending on the room’s humidity. The sensors are made of several stacked polyamide strips that begin to expand in relative humidity of about 35 %. They are connected with the air vent flap so that it opens wide when interior air is moist and is less widely open when air is dry. Combined with an air exhaust system, these vents can provide optimum ventilation for all connected rooms. An exhaust air ventilator used should automatically adapt its output to negative pressure in the exhaust air duct, responding to the opening width of air vents to avoid fluctuations in pressure and too much negative pressure in rooms (Fig. C 3.8).

the building through air vents on the windward side, and exhaust air exits through vents in the facade’s lee side. Individual rooms must be connected by overflow openings, which can be provided in the form of slots in door panels or by slightly shortening doors. If rooms require sound insulation from each other, soundproofed overflow elements can be inserted into a door panel or, even better, into a fixed slot above the door opening. Natural ventilation through air vents (Figs. C 3.10 und C 3.14) cannot replace the opening of windows, but it at least lowers necessary ventilation periods by increasing the base air exchange rate. This reduces the risk of interior air becoming too humid, which can cause damage from damp and the growth of mould on building structure surfaces, a common occurrence today in buildings with very airtight windows. Combination with exhaust air systems In buildings that use natural ventilation, the air exchange rate and flow directions inside depend entirely on weather conditions and cannot be influenced by users, so air vents integrated into windows are often combined with exhaust air systems that remove

C 3.7

C 3.8

C 3.9 C 3.10 C 3.11 C 3.12

C 3.13 C 3.14 C 3.15

Natural ventilation Passive air vents can be used for natural ventilation in buildings with no mechanical ventilation systems. Here, outside air enters C 3.10

200

C 3.16 C 3.17

Typical volume flows of various types of windowintegrated air vents depending on the prevailing pressure difference Correlation between the relative humidity in a room and the volume flow through a humiditysensitive ventilation element with a pressure difference of 10 Pa Moisture-adaptive air vent Sliding louvred ventilator to assist natural ventilation Diagram of an active window ventilator in the window reveal Frame extension with two counter-operating vents with renewable energy heat exchangers, one on top of the other Frame extension Natural ventilation in the form of cross ventilation through outdoor air vents Mechanical ventilation with an exhaust ventilator: fresh outside air is drawn in through window vents. Hybrid ventilation with ventilation shaft and support ventilator Mechanical ventilation with active window vents

Technical building components in and around windows

Cover Ventilator housing Airflow profile

C 3.12

C 3.11

stale, humid air, usually from kitchens, bathrooms and toilets. The negative pressure created in the building causes fresh outside air to flow selectively through all window vents or overflow openings into rooms. Here too, all the rooms must be connected. Fresh air enters the building at the outside temperature, so it must be heated in winter before it reaches occupied rooms. Heaters, which are often installed near or under windows anyway, can prove beneficial around windows with integrated air vents. Such installation, however, is no longer a matter of course with today’s very well-insulated windows, so in some cases incoming air will have to be specifically heated (Fig. C 3.15). This ventilation concept does not allow for direct recovery of the heat in exhaust air, although exhaust air can be used as source of heat for an air / water heat pump for heating service water. A simple version of this ventilation principle can also be created without a classic exhaust air system for interior rooms with simple exhaust fans. The exhaust fans, which are already installed, continuously draw in air through the window vents. Although the amounts of air they move may be too small to completely meet hygienic requirements, a sufficient exchange of air for protection from damp as prescribed in DIN 1946-6 can usually be ensured in this way. Hybrid ventilation as defined in DIN EN 12 792 Vertical shafts were formerly often used to support natural ventilation in residential buildings. They function based on the principle of the thermal lift that occurs in a vertical space whose temperature is higher than that of its surrounding environment. If this prerequisite is not fulfilled, the airflow may stop or even reverse. Hybrid ventilation supplements this principle by installing a ventilator in the shaft that operates when thermal lift is insufficient to ensure the desired exchange of air (Fig. C 3.16). Active air vents

Active air vents have integrated ventilators whose air throughput can be adjusted selectively, usually by means of control panels

directly attached to the device. Devices with sensors for CO2, humidity and pollutants in the form of volatile organic compounds (VOC) regulate the exchange of air automatically depending on the condition of the interior air. Many devices can also be incorporated into the overall building services systems. In contrast to systems with passive air vents, which are based on rooms with a connected air supply, active window ventilators supply each room with fresh air, independently of the other rooms (Fig. C 3.17). Window ventilators for residential buildings Active window ventilators cannot be integrated into windows, because they take up much more space than purely passive air vents. They are designed mainly for installation in window lintels, reveals or parapet areas. They are designed to fit in with wall thicknesses currently in common use, which makes it possible to conceal them in most cases. Another alternative is to install them in an enlarged blind frame (Fig. C 3.11– C 3.13). These devices are typically designed for volume flows ranging from 6 to 40 m3/h, so they can meet normal residential requirements, such as the fresh air needs of one or two people in a room. The fact that flows of intake and exhaust air in window ventilators are channelled past each other in close proximity makes it easier to recover the heat in the exhaust air in winter, so many of these devices are equipped with heat exchangers. As well as crossflow and counterflow heat exchangers, some unusual, space-saving solutions are employed. Their very compact size and correspondingly small heat transfer surfaces mean that these devices do not achieve the heat recovery rates of larger heat exchangers that are now standard in central intake and exhaust air systems. Typical heat recovery rates designed for volume flows in continuous operation range from 45 to 70 %, but heat recovery rates will be much lower for maximum flow rates. Higher heat recovery rates of up to 80 % are possible if the humidity contained in the room’s air is also recovered by

C 3.13

5

1 2

1 2 3 4 5

3

3

4

Wind pressure Air flowing in through the vent Overflow openings between rooms Air flowing out through the vent Wind suction C 3.14 4 1

2

3

3

2

1 Air extracted from kitchens and bathrooms 2 Air flowing through outdoor air vents into living rooms and bedrooms 3 Overflow openings between rooms 4 Heat recovery through a service water heat pump (optional) C 3.15

1

4

3

2

4

1 Shaft ventilation using thermal lift 2 Support from a ventilator in unfavourable temperature conditions 3 Overflow openings between rooms 4 Air flowing through outdoor air vents into living rooms and bedrooms C 3.16

1

1

1 Ventilation, room-by-room C 3.17

201

Technical building components in and around windows

Intake air outside the boundary layer

Outside air flap PCM element

Transit of heated air

Installation in parapet area

Installation in double floor

Installation in suspended ceiling C 3.18

an enthalpy exchanger. Their heat transfer surfaces consist not of the usual metal, but of a membrane through which moisture from exhaust air can be transferred to intake air (Fig. C 3.22). Another type are ventilators with regenerative heat exchangers. They have a ceramic heat storage element through which air is passed in an alternating mode. When the device transports air from a room to the outside, its storage element stores the air’s heat. The ventilator fan rotation then reverses, releasing heat into the air drawn into the room. This method can produce heat recovery rates of up to 96 %. In all systems with heat recovery, the intake air is preheated before entering the room, which largely prevents problems with perception of comfort. They do not subsequently heat intake air. These devices’ larger dimensions, compared with simple air vents, enable them to more effectively filter outside air, with the addition of multilayered filters for example. Devices with filters in at least class M5 as specified in DIN EN 779 that have special pollen filters and fulfil other requirements specified in DIN 4719 can be labelled with an “H” indicating a “higher hygiene standard”. Passive air vents must also be soundproofed against exterior noise and comply with the acoustic properties specifications in DIN 4109. The breaches in an exterior wall required for

C 3.20

202

the exchange of air may significantly weaken a facade’s overall acoustic system. The fairly large bores of up to 200 mm in diameter required for ventilators with regenerative heat exchangers are problematic in this context if they are drilled straight through a wall [1]. Deflecting the airflow by positioning an exterior vent slit in the reveal not only improves the vent’s integration into the facade design, but also the sound insulation, because noise is reflected back to the baffle. Devices of either type should only be installed in locations exposed to high levels of outside noise after careful evaluation of their advantages and disadvantages. Integrated ventilators themselves may also produce noise, which can impinge on affected rooms. There are no legal regulations on permissible noise in your own unit. The standard desired must be agreed on in each case and used as a basis for planning. To comply with high quality planning requirements, the use of sound location devices as defined in DIN 4719, which fulfil certain soundproofing characteristics in keeping with regulatory requirements, may be advisable. These devices’ audibility in an interior is specified by their manufacturer. Facade-integrated ventilation unit

The window ventilators described in the section above cannot adequately transport the amounts of air required to ensure hygienic conditions in office, administrative and educational institution buildings. In recent years, however, decentralised facade-integrated ventilation units have increasingly been used here too because they are much easier to build than central ventilation systems, which require considerable space for routing ductwork. User acceptance of them is also much higher, as air supply and conditioning can be individually regulated room by room. Effectively planned decentralised ventilation units require less energy for heating and cooling air than central systems [2], not least because they can be switched off in individual rooms when not in use, although they are not generally able to humidify or dehumidify air. VDI (Ger-

C 3.19

man Engineers Association) Guideline 6035 contains information on planning, operating and maintaining decentralised ventilation systems, and their main quality criteria and testing processes are compiled in Specification sheet 24 390 of the German Engineering Federation (Verband Deutscher Maschinen- und Anlagenbau – VDMA). These are mainly supply air and exhaust air ventilators, although pure supply air ventilation units that centrally draw off exhaust air are also available. The cross sections of ducts required for decentralised ventilation of office space and the space required by heat exchangers and sound absorbers make it impossible to entirely integrate them directly into windows in the way that is possible with residential ventilators. These devices are instead installed behind cladding, in parapet areas or in double flooring to save space. Ventilation units can also be integrated perpendicularly into the facade or hung from the ceiling. Openings through which outside air enters must be integrated into the facade. For devices under a ceiling, fixed inserts in the upper areas of windows can be used, while continuous slit vents at floor height may be suitable for devices installed in double flooring (Fig. C 3.18). Fresh air intake directly through a facade can be problematic. Central ventilation systems can draw in outside air from any location, but conditions on the facade directly influence the quality of the intake air of facade-integrated devices. In summer in particular, this can be problematic because solar radiation may heat the air near the facade. Demonstration projects have successfully trialled intake elements that project out of the facade and in this way draw cooler air into the building. Because the heated layer of air is just a few centimetres thick, a slim profile is enough to achieve the desired effect (Fig. C 3.19). Light-coloured facades also heat up less. Positioning openings in shaded areas of a facade, e.g. behind or under a blind housing, can also be helpful if there is adequate rear ventilation. Positioning vents above windows results in lower temperatures because they

Technical building components in and around windows

Two-pipe system 3

2

Three-pipe system 3

1

5

2

4

3

1

5

2

4 67

Four-pipe system

1

5

4 8 9 10

1 2 3 4 5 6 6 7 7 8 9 10 11 12

Exhaust air Outgoing air Outside air Supply air Air heat exchanger Inflow, heating / cooling Return flow, heating / cooling Inflow, heating Joint return flow Inflow, cooling Return flow, heating Return flow, cooling

8 11 10 12 C 3.21

absorb less radiation than the adjoining opaque surface of the facade [3]. If heating energy requirements is the predominant issue in a building, the heat of the incoming air may help to save energy over its annual energy balance [4]. This is, however, rarely the case in office buildings. Air conditioning of incoming air Facade-integrated ventilation units usually use air /water heat exchangers connected to a central pipe system to heat or cool incoming air (Fig. C 3.21). The simplest form of installation is a two-pipe network with an inflow pipe and a return flow pipe. The inflow pipe supplies devices with cold water in summer and hot water in winter. If both heating and cooling has to be available at the same time, in transitional seasons for example, these devices require separate cold and hot water supplies. If their water cycles are completely separate, they form a four-pipe network. A compromise is a three-pipe system, where devices are run separately with cold and hot water but the return flow is consolidated. Such systems, however, need more energy due to the mixing of cold and hot water in the return flow, so they are now no longer used. The cooling circuit inflow temperature is limited because no condensate can be allowed to accumulate on the heat exchanger. It would have to be collected and released, which would be much more complex and costly in a decentralised system than in a centralised one. The cooling capacity of devices can therefore only be adjusted by varying the amount of air passing through them, which is why many decentralised devices, as well as supplying the amount of outside air required to maintain hygiene in recirculating air operations, are also able to draw air out of the room and return it after cooling. PCM integration One very energy-saving method of cooling incoming air is to use phase change materials (PCM) as heat storage. These materials, such as salt hydrates and paraffin, can be made with a melting point of about 19 – 22 °C. They are installed in panel form in the air

duct. When outside air with a temperature above the melting point of the PCM panels flows between the panels, they begin to melt and absorb large amounts of energy, which is drawn out of the intake air. The heat in PCM storage can be released at night by passing cool outside air through the unit. The effectiveness of this cooling principle is limited by the amount of PCM in the ventilation system. Phase change material costs are currently still high, so PCM storage units are usually fairly small and more of an option for improving comfort than a replacement for active cooling. It should be noted that PCM panels cannot harden when temperatures at night are above their melting point, so they cannot be used during long periods of warm temperatures.

C 3.22

trol variables are usually room temperature and outside temperature. Wind and rain detectors stop them from opening in unfavourable outside conditions and communicate with automated building systems via cable or wireless connections. Such controlled natural ventilation can, in many cases, replace mechanical ventilation also during the day (Fig. C 3.23, p. 204). This application can also use the CO2 and VOC content of interior air and its relative humidity as control parameters. Users should be able to override automatic controls if a window should temporarily not be opened because of noise outside, for example. To prevent unnecessary heat losses, automated building systems should ensure that the heaters in the room are switched off when the windows are open.

Controlled natural ventilation

Electromotive drives have been used for a long time to mechanically open windows as well as to operate opening vents and smoke and heat extractors that are otherwise hard to reach. Depending on the type and size of window involved, chain, spindle, scissor or locking drives are used. They can be integrated into sashes or fitted on frames (see “Solution principles for adjustable openings”, p. 36ff. and “Building connection and structural context”, p. 120ff.). Linear drives (racks) are available for roof glazing, skylights, the upper areas of windows and glass louvers. When connected to automated building systems, such drives can now be controlled depending on weather conditions and indoor climates, presenting new options for efficient and energy-saving night ventilation. Cool outside air flows into rooms at night to release the heat energy stored in structural elements during the day. Studies have shown that this natural measure is much more efficient if opening elements are suitably selected and positioned and can achieve higher air exchange rates than mechanical ventilation systems [5]. It also dispenses with the mechanical drive energy otherwise required. Buildings are not occupied at night, so windows must be opened automatically. The con-

Air curtains

Air curtains are ventilation devices that, in contrast to the devices described above, do not supply rooms with fresh air, but create a flow of air in a facade opening to prevent an exchange of air between an interior and its environment. Typical applications for air curtains are high-traffic department store doors and industrial and delivery warehouses that have to stand open for long periods (Fig. C 3.24, p. 204).

C 3.18

C 3.19

C 3.20

C 3.21

C 3.22

Facade-integrated ventilation unit in a parapet area, in a double floor, and in a suspended ceiling Ventilation unit intake opening projecting out of the facade to prevent heated outside air near the facade from entering. Office building, Hamburg (D) 2005, nps tchoban voss Ceiling-integrated decentralised ventilation unit for classrooms. Openings for drawing in outside air and blowing out exhaust air are integrated into the windows. Extension for the PhilippMatthäus-Hahn secondary school, LeinfeldenEchterdingen (D) 2011, Schädler & Zwerger Architekten Decentralised facade ventilation units with two-pipe, three-pipe and four-pipe structures (simplified sketches without ventilators, filters and sound absorbers) Ventilation unit integrated into a parapet area with cross countercurrent enthalpy exchanger

203

Technical building components in and around windows

C 3.23

Depending on pressure ratios in the building, air curtains are installed in various ways (Fig. C 3.25). If the entrance is sheltered or there is excess pressure in the building, the air in the curtain rolls inward. The air in the air curtain will not require much heating, because it draws in interior air and blows it out again. Greater wind loads or negative pressure in the building mean that the air curtain will have to roll outwards, in other words, they draw in cold outside air, thus requiring more energy and frost protection. This type of air curtain causes no inward airflow at the floor level, which improves comfort and makes it possible to use the area around the door. Air curtains that combine both principles, with air rolling both inwards and outwards, provide especially effective air screens. These systems’ energy requirements depend largely on their exhaust. Vane louvres and special jet nozzles are commonly used. The air is heated by water /air heat exchangers or electrical resistance heating. Air curtains can greatly reduce the undesirable exchange of air and with it heat losses in winter and overheating in summer, although additional energy is required to move the air. The airflow must also be heated to maintain comfort, thus requiring more energy. This heat does, however, largely add to interior warmth, so it cannot be regarded as an additional

C 3.24

204

energy requirement. Combining an automatic sliding door with controls to operate the air curtain only when the door is open can prove very effective. Figure C 3.26 shows the loss of energy due to infiltration for various types of entrance doors, as identified in a study by the Swiss Federal Office of Energy (Bundesamt für Energie – BFE) [6]. The values specified assume correct operation of the air curtain, i.e. complete coverage of the opening and a precisely adapted exhaust velocity. If velocity is too low, the air curtain will not reach the floor; if it is too high, the airflow will divide on the floor and air will be lost to the outside. External influences, such as strong winds or improperly adjusted ventilation systems in buildings, can destabilise air curtains, so they often do not achieve their theoretically possible energy savings targets.

Heating With the right equipment, facade-integrated ventilation units can also be used to heat spaces, as described above. Even independent of ventilation, it can be expedient to install heating components in or around windows and facade openings. Among the reasons for this type of installation are that it can prevent condensation due to higher surface temperatures

a

on glazing and the frame profile as well as cold air downdraughts on high glass surfaces while also improving the comfort of areas near the facade and directly contributing to heating the room. Preventing condensation

DIN 4108-2 stipulates that relative humidity on interior structural element surfaces may not exceed 80 %. This prevents condensate accumulating on surfaces and in material pores near surfaces and forming a basis for damage to materials and for mould growth. For planners, the main criterion is the temperature factor fRsi defined in DIN EN ISO 10 211, which, assuming a normal interior climate in a dwelling with an air temperature of 20 °C and relative humidity of 50 %, must be at least 0.70 at every point on a surface. Windows and curtain wall facades, on which small amounts of condensate may collect temporarily as long as the surface is treated so that it does not absorb water and water cannot penetrate adjoining structural elements, are explicitly excluded from this requirement (see “Preventing condensation and mould formation”, p. 64f.). Trace heating Because of the thermal bridge effect of the bonded edges of multi-pane glazing units, surface temperatures at the edges of panes in many units can fall to under 10 °C in low

b

C 3.25

Technical building components in and around windows

Airtight building Full capacity1 Each person

Very leaky building Full capacity1 Each person

Normal doors (1 m wide)

12 kW

24 kJ

90 kW

180 kJ

Automatic sliding doors (1.60 ≈ 2.08 m) without warm-air curtain

20 kW

80 kJ

100 kW

400 kJ

Automatic sliding doors with warm-air curtain

13 kW

52 kJ

85 kW

340 kJ

Porch

18 kW

45 kJ

95 kW

240 kJ

Revolving door, large ( 4.75 m)

17 kW

350 kJ

19 kW

390 kJ

Revolving door, small ( 4.20 m)

13 kW

150 kJ

15 kW

170 kJ

1

Doors permanently open or revolving doors constantly revolving C 3.26

outdoor temperatures, allowing moisture to condense there. Skylights that release lots of heat to a cold sky at night are especially affected. Some manufacturers offer heating strips designed to prevent this kind of condensation by heating the panes. The strips contain heating wires and are adhered either behind the glazing bead on the pane or integrated into fitted profiles. This resistance heating, which can be regulated depending on temperature, prevents condensation even in unfavourable structural conditions such as badly insulated old windows. With a typical electrical consumption of 10 W/m, their electricity use is not negligible, as a large amount of the heat they produce is not added to interior heating but released outside through the bonded edge. Technical structural measures, such as insulated or sufficiently large frame profiles and thermally separate spacers, should help prevent condensation in new windows (see “Spacers and edge bonds, ‘warm edge’ ” p. 92f.). Heated facades For buildings with very warm, damp interior climates, such as indoor swimming pools or heated greenhouses, these measures are normally not enough to prevent condensate at the edges of panes and facade profiles in winter. One possible solution is to run hot water through facade profiles, using them to heat the space as well as raise surface tem-

peratures to an uncritical level. As this principle has been in use for over 30 years, manufacturers can provide proven profile geometries and connection systems. Planners should ensure that water flows evenly through all parts of the facade. To this end, pressure losses from individual sections must be hydraulically balanced with suitably designed orifices of the requisite number and size. Opening sashes and insert elements can be planned in the usual way without having to be connected to a heating system (Fig. C 3.27). Higher demands on insulation have resulted in a greater focus on the relatively high heat losses from older, heated facades due to badly insulated joints between individual panes. To counter these heat losses, 30 – 40 mm-thick insulating blocks can be installed between the facade profile and glazing, which greatly changes a facade’s appearance. The heated facades currently being installed more usually accommodate insulation in the form of an elastomeric foam strip at the glazing level. As well as improving design, this construction method offers structural advantages, as glazing loads can be transferred into the facade profile with less cantilever effect (Fig. C 3.28). Cold-air downdraughts and comfort

When warm interior air comes into contact with cold surfaces it cools, becomes heavier, and sinks. Windows and glazed facades are

especially affected because they have relatively low thermal resistance and low surface temperatures in winter. As described in the section on “Cold-air downdraughts” (p. 58), this causes unpleasant draughts in spaces with large areas of glazing, even with highquality thermal insulation glazing. Technical measures to prevent cold-air downdraughts will be required in many cases. For floor-toceiling windows, floor level heating, e.g. in the form of a trench heater, may be enough to solve the problem. Higher glass facades may require additional heating elements, which are often positioned along transom profiles (Fig. C 3.29, p. 206). Convector heaters attached to the facade and connected to a heating circuit are suitable for this purpose. Electrical resistance heating connected to the facade with profiles is less complex to install but uses more primary energy, so it is more rarely installed. Directly heated facades like those described above are another alternative. Systems that add to interior heating

One approach to using windows to heat rooms is to use panes with a metallic, electrically conductive coating. When a current is applied to the pane, electricity flows and the metal coatings release heat, depending on their electrical resistance. To protect the coating, it is applied on the side of the inner pane facing the space between the panes. Air vent duct

C 3.23

C 3.24 C 3.25

C 3.26

C 3.27 C 3.28

Facade with power-operated top-hung, outward opening windows in the Nottingham Emmanuel School (GB) 2008, Seymour Harris Architecture Air curtain Functional principle of an air curtain with air cylinder a Turning inwards b Turning outwards Heat losses of variously designed public entrances with a temperature difference of 20 K between inside and out Functional diagram of facade-integrated heating Cross section of a heated facade a With insulating elements between the hollow sections and glazing b With elastomeric foam strips in the installation joint

Mullions

Transoms a

Supply flow b

Return flow C 3.27

C 3.28

205

Technical building components in and around windows

C 3.29

The benefit of heating normally cold window surfaces in winter and simultaneously adding to interior heating and improving comfort seems persuasive. Like all vertical surface heating, it produces a room temperature profile that is even and perceived as pleasant. This technique does, however, have some disadvantages. The coatings’ optical properties reduce the glazing’s total energy transmittance and with it solar heat gains. Temperature differences between an inner pane used for heating and an outer pane exposed to the outdoor climate, which can be up to 60 °C, impose a heavy load on the bonded edge. This is also electrical direct heating, so it uses more primary energy in the form of conventionally generated electricity than most alternatives.

b

tions to control systems and register the opening states of windows should be mentioned in this context.

Lights installed in a window frame between the viewing area (window’s middle section) and its upper area (transom) can take on an additional function by day and reflect incident daylight through the window’s upper area into the room’s depths and onto the ceiling. Such approaches have been successfully implemented in various model projects but not widely implemented so far, probably because of the greater cost and effort involved in installing cables in frames, compared with conventional installation in walls and ceilings (Figs. C 3.31 and C 3.32).

Lighting Facade illumination

Windows are transparent structural elements that not only provide visual contact between an interior and exterior, but also supply a space with daylight (see “Use of daylight”, p. 186ff.). At the same time, they make a major contribution to a building’s overall appearance. Integrating lights into facade openings can supplement daylight and decisively shape a facade’s design impact. Facade-integrated interior lighting

For the purposes of optimising daylight use, how a room is used depends largely on the position and size of windows. If it does not receive enough daylight to ensure the required luminous intensity, artificial lighting must be switched on. It is advisable to position artificial lighting so that it creates a lighting situation similar to a natural one, especially in terms of the incident angle of light in the room. This can be done by integrating lights into a window or facade structure. An office with the usual depth can be completely lit from the facade by lighting from two points (direct lighting in an area near the facade or indirect lighting in the depths of the room). Here it should be noted that the angle of direct lighting should not be too great because otherwise

206

C 3.30

a

glare can occur. The entire space can also be indirectly lit from a single point. Reflecting surfaces on a ceiling can provide a more targeted and efficient distribution of light in a room than diffuse reflection on the ceiling (Fig. C 3.30) [7].

Highlighting buildings by illuminating their facades at night has long been part of the building designer’s toolkit and has helped shape the image of many cities. While facades have to date been illuminated mainly by powerful spotlights with halogen metal-halide lamps installed near the building or more rarely on a substructure within it, LED technology with its smaller dimensions means that lights can now be integrated into the facade itself, in the facade profile or the glazing bead of windows. This can also greatly reduce installed output and electricity consumption (Figs. C 3.33 and C 3.34).

Opening-state sensors

Information on whether a window is wholly open, partly open or not open is relevant for managing heating and cooling in rooms and for security and protection from breakins. It can be gained from magnet contacts, so-called “reed switches”, which are elements made of two overlapping metal tongues fused close together in a thin-walled glass tube. When a magnet approaches, the tongues approach each other until they touch. In windows, the reed switch is in the frame, while the magnet is in the sash frame. When the window is closed, the contact is closed and electricity flows, which the control system registers. If they are suitably positioned on a window, they can determine whether a sash is tilted or fully open. The magnet-and-reed switch contact can be either installed on a frame or concealed in the frame. In Germany, if information on opening states should be passed on to protect from break-ins, to comply with the required security standard, the contacts must conform to the specifications in VdS guideline 2311. Here it is decisive whether a window or door is locked or unlocked. Separate bolt switch contacts exist for this purpose. They are installed on the lock plate and activated by the bolt. Similar sensors are also available for large doors and are usually installed in the floor.

Building automation components

Glass breakage sensors

Given the major role that windows play in a building’s energy balance due to solar radiation input and heat transport through the exchange of air between inside and out (see “Passive solar energy use”, p. 170ff., “Active solar energy use”, p. 190ff.), it is natural that they be integrated into the automation systems of high-tech buildings. As well as the actuators described above, sensors which pass on information on weather condi-

Glass breakage sensors are a major element in burglar alarms. In their most common form, they consist of a piezoelectric element that reacts to pressure and registers vibrations in the pane. The alarm releases a signal when it registers vibration patterns that typically occur when glass breaks. The sensors can cover areas of glass ranging from 1 to 4 m2 in size. Older planar burglar alarms formerly made of thin foils or wires stuck to panes are now no longer used.

Technical building components in and around windows

Light-directing blind Facade mullion Acrylic or glass cover

Angle

Reflector Possible slit opening with opaque cover C 3.31 Sensors that measure the characteristics of air in a room

Sensors for measuring a room’s air temperature and CO2 content have been integrated directly into window frames and connected to electromechanical window openers in research projects. Given the small size of sensors now available, this is possible, but the frame must have appropriately prepared cavities. The disadvantage of this concept is that the values measured near a window do not necessarily reflect conditions in the occupied area of the room. Air temperatures especially can vary by several kelvin between a window and the middle of a room [8]. Sensors are still more commonly installed deeper within the room, independent of the window.

C 3.29

C 3.30

C 3.31

C 3.32

C 3.33 C 3.34

Convectors along the facade of Terminal 2, Munich Airport (D) 2003, Koch + Partner Architekten und Stadtplaner Lighting plan for an office a From two points – direct / indirect b Indirect, with reflectors Facade-integrated lighting combined with daylight refraction, Stadtwerke Bochum (D) 2004, Gatermann + Schossig, Köster Lichtplanung Facade-integrated lighting combined with daylight refraction, Landesamt für Statistik und Datenverarbeitung, Schweinfurt (D) 1998, Kuntz+Manz Architekten, Köster Lichtplanung Facade lighting with LED lights integrated into the window structure Example of LED lights installed in the glazing bead

Notes: [1] Pietruschka, Dirk et al.: Energetische und akustische Sanierung von Gebäuden – vom Altbau zum akustisch optimierten Passivhaus. Forschungsprojekt No. 122 002 008P, HFT Stuttgart, final report February 2011 [2] Mahler, Boris et al.: DeAL. Evaluierung dezentraler außenwandintegrierter Lüftungssysteme. Abschlussbericht. Förderkennzeichen 0327386B. Published by Steinbeis-Transferzentrum Energie-, Gebäude- und Solartechnik, Stuttgart 2008 [3] Voss, Karsten: Energieoptimiertes Bauen. Dezentrale Lüftung in Bürogebäuden – Mikroklimatische und baukonstruktive Einflüsse. Final report. Support code 0327386A. University of Wuppertal, 2010 [4] Erhorn, Hans et al.: Weiterentwicklung und Evaluierung von Technologien und von Bewertungsmethoden zur Steigerung der Gesamtenergieeffizienz von Gebäuden (EnEff 06). IBP report WTB-02-2007. Stuttgart/Holzkirchen 2007 [5] Eicker, Ursula; Schulze, Tobias: Kontrollierte natürliche Lüftung für energieeffiziente Gebäude. In Jürgen Pöschk (ed.): Energieeffizienz in Gebäuden – Jahrbuch 2012. VME Verlag und Medienservice Energie. Berlin 2012 [6] Züricher Energieberatung / Bundesamt für Energie: Merkblatt Gebäudeeingänge mit grossem Publikumsverkehr. Zurich 1998 [7] Pohl, Wilfried et al.: LichtAusFassade. Optimierte Tages- und Kunstlichtversorgung über Fassaden – Beurteilung der Energiebilanz und der visuellen Qualität. Berichte aus Energie- und Umweltforschung 26/2012. Bundesministerium für Verkehr, Innovation und Technologie (pub). Aldrans 2012. www.hausderzukunft.at/hdz_pdf/berichte/endbericht_1226_ lichtausfassade.pdf [8] Pawelczak, Dieter et al.: Innovative Mikroaktorik für die Gebäudetechnik (IMiG). Verbundprojekt im Rahmen des BMBF-Förderkonzepts “Mikrosystemtechnik 2000+”. Förderkennzeichen 16SV1614. Final report of subproject by Bundeswehr University Munich, 20.10.2005. http://edok01.tib.uni-hannover. de/edoks/e01fb06/510185266.pdf

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Life-cycle assessments for windows and exterior doors Joost Hartwig

C 4.1

Manufacturing, using and disposing of doors, windows, and their components consumes resources and energy and produces emissions and rubbish. The effects of such components on the environment can be presented in lifecycle assessments and the elements’ technical properties and economic aspects taken into account in choosing products.

Life-cycle assessments DIN EN ISO 14 040 states that a life-cycle assessment refers to potential environmental effects (e.g. use of resources and the impact of emissions on the environment) over the course of a product’s “life”, from raw materials extraction through production, use, waste treatment, recycling and up to final disposal [1]. A life cycle assessment (LCA) analyses a product’s life cycle and describes its impact on the environment, taking resources consumed (e.g. energy sources such as oil or gas) and emissions (e.g. greenhouse gases) into account. These analyses distinguish between “cradle-to-grave” assessments, which examine a product’s entire life cycle, and “cradle-to-gate” assessments, which only evaluate up to a product’s manufacture (until it leaves the manufacturer’s gate) [2]. Lifecycle assessment methods are used for many products and groups of products. In this context, a construction “product” can be an individual construction material, a structural element or an entire building. Life-cycle assessments can be used to improve products’ environmental characteristics, provide information to decision makers, in the selection of relevant indicators for products’ environmental properties and for marketing purposes [3]. As part of implementation of the EU’s revised construction products regulation, all products launched on the market after 1 July 2013 must meet one of seven basic requirements for sustainable natural resources use formulated in the regulation [4]. Verification of compliance is provided in an Environmental Product Declaration, which is based on a lifecycle assessment.

208

Life-cycle assessment methods

The DIN EN ISO 14 040 and 14 044 series of standards regulate the normative fundamentals of life-cycle assessments. DIN EN 15 804 contains further specifications for life-cycle assessments of construction products. These standards also form the basis for the Type III environmental labelling of Environmental Product Declarations (EPD), which are described in DIN EN ISO 14 025. DIN EN ISO 14 040 defines a life-cycle assessment as having four phases: the goal and scope definition phase, the inventory analysis phase, the impact assessment phase and the interpretation phase (Fig. C 4.2) [5]. The functional unit, i.e. the product being assessed and its function, is the basis for the steps in the calculations and results of a life-cycle assessment and enables life-cycle assessments of different products with the same function to be compared. Functional units are often specified in units of the product commonly used in the trade, e.g. m3, kg, piece etc. Scope definition includes system boundaries and cut-off criteria. System boundaries describe the processes a product undergoes throughout its life. Here the inputs and outputs are ideally elementary flows beyond system boundaries, i.e. chemically inseparable materials (Fig. C 4.3). Within the product system under review, the cut-off criteria are the boundaries of inventory analysis. These are usually estimated at a minimum of 1 % of material mass, primary energy consumption and environmental relevance. The sum total of negligible material mass may be no more than 5 % [6]. The cut-off criteria for ecologically unsafe materials (e.g. plasticisers in plastics) must be reviewed in each case and possibly overridden [7].

C 4.1 C 4.2

Used windows for sale, Jaipur (IND) Progress of a life-cycle assessment study as defined in DIN 14 040 C 4.3 Phases in the life cycle and system boundary in a life-cycle assessment as defined in DIN EN 15 804

Life-cycle assessments for windows and exterior doors

In the inventory analysis phase, the material and energy conversion processes relevant to the product system are recorded and quantified, taking into account the system boundaries and cut-off criteria. These processes involve energy, raw material and fuel inputs, products, co-products and waste, and emissions into air, water and soil [8]. The impact assessment phase determines the contribution of inventory analysis results to specific potential environmental impacts [9]. To do this, inventory analysis results are allocated to one or more impact categories. The categories describe a specific potential environmental effect (e.g. greenhouse potential) and are defined by means of a material equivalent (e.g. CO2 equivalent). All the material flows in the inventory analysis that contribute to a certain impact category are converted into their material equivalent and consolidated using fixed characterisation factors. In this way, hundreds of emissions in soil, water and air can be described in terms of a few potential environmental effects. The following impact categories have been identified for Environmental Product Declarations for construction products [10]: • Global warming • Ozone depletion • Acidification of soil and water • Eutrophication (the oversupply of nutrients / fertilisers) • Photochemical ozone creation • Depletion of abiotic resources (materials) • Depletion of abiotic resources (fossil energy sources)

It should be noted that this list does not cover a product’s complete environmental impact since a range of impact categories are still undergoing scientific research. These are also potential environmental effects, which leave the chronological and spatial effects of exposure to materials largely unconsidered [11]. A further weighting of indicator values of different impact categories by consolidating them into a single indicator value in an “ecopoint system” is not scientifically justifiable [12]. Weighting can only be made based on values, although the equal weighting of all impact categories also involves a decision based on values. This kind of simplified representation of impact assessment results also involves a significant loss of information, yet the use of “eco points” has become fairly common [13]. In the sustainability certification of buildings, there is also a weighting of impact assessment results instead of an overall evaluation of ecological quality, although this process belongs more to the “interpretation” phase. A life-cycle assessment study concludes with the interpretation phase, in which the results of the inventory analysis and impact assessment are jointly evaluated, their conformity with the goals and scope of the assessment reviewed, and the results and conclusions documented in a report. The report and the assessment it is based on can then be submitted to an independent group of experts for critical review. This will be especially necessary if compari-

Establishing of goals and scope definition

Inventory analysis

Interpretation

Impact assessment

C 4.2

sons of competing products are to be made or if the study is destined for publication [14]. Impact categories of a life-cycle assessment

DIN EN 15 804 requires the impact categories listed below to be taken into account and documented in Environmental Product Declarations for construction products. Global warming potential Global warming potential (GWP) describes the influence of emissions produced by people on the atmosphere’s heat absorption. Gases such as CO2 and methane increase heat absorption and contribute to heating the atmosphere, the so-called greenhouse effect. A material’s global warming potential is specified in kilograms of CO2 equivalent [15].

Consequences: sea level rise, forest dieback, species extinction, extreme weather events etc. System boundary in a life-cycle assessment

Waste

Emissions

Emissions

Waste

Emissions

Waste

Emissions

Waste

Emissions

Emissions

Waste

Emissions

Emissions

Waste

Emissions

Current environmental impacts: greenhouse effect, ozone hole, summer smog, acidification, over-fertilisation, pollutants etc.

EnEv

Resources depletion

Transport

Product manufacture

Transport

Building construction

Building operation

Dismantling

Transport

Dismantling

A1

A2

A3

A4

A5

B1–7

C1

C2

C3/4

Resources

Energy

Resources

Energy

Resources

Disposal phase C1–4

Energy

Energy

Resources

Resources

Energy

Resources

Usage phase B1–7

Energy

Resources

Energy

Resources

Energy

Energy

Production phase A1–5

Use of renewable and non-renewable primary energy sources, use of abiotic and biotic resources

Consequences: shortage of available resources C 4.3

209

Life-cycle assessments for windows and exterior doors

C 4.4

C 4.5

C 4.4 Greenhouse made of used window elements, Rangley (USA) 2009, Shannon Rankin and Justin Richel Life-cycle assessment data for various window and door components on the basis of Environmental Product Declarations (EPDs) of individual manufacturers (as of October 2013)

Ozone depletion potential Ozone depletion potential (ODP) describes the reduction of concentrations of ozone in the stratosphere due to anthropogenic emissions, which allows more UV-B rays to hit the Earth’s surface [16]. The ozone depletion potential is measured in kilograms of R 11 (trichlorfluormethane) equivalent. Photochemical ozone creation potential Photochemical ozone creation potential (POCP) describes the formation of certain chemical compounds, e.g. ozone, under the influence of ultraviolet radiation (sunlight) and certain air pollutants (volatile organic compounds, carbon monoxide), with the participation of nitrogen. This effect is also called summer smog [17]. Ozone creation potential is stated in kilograms of C2H4 (ethylene) equivalent. Acidification potential The introduction of acidic substances into air, soil or water is called acidification (acidification potential – AP). It is caused mainly by sulphur dioxide (SO2), nitrous oxide (NOx) and ammonia (NHx), and its consequences range from forest dieback and fish die-offs in unbuffered lakes to damage to buildings. Acidification potential is specified in kilograms of SO2 (sulphur dioxide) equivalent [18]. Eutrophication potential (EP) Over-fertilisation or eutrophication is the introduction of excessive amounts of nutrients, mainly nitrogen and phosphorus, into an ecosystem. It changes biodiversity through the excessive growth of biomass in terrestrial and aquatic ecosystems. Greater algal growth in water increases oxygen consumption and can cause a body of water to “die”. Pollution with high concentrations of nitrogen can also impair the drinking water quality of surface bodies of water. Eutrophication potential (EP)

210

sums up substances and the effect of their PO43- (phosphate) equivalent for the purposes of comparison [19]. Primary energy requirement

A building material’s primary energy requirement is the consumption of energy (resources) required to manufacture, use and dispose of the material. A distinction is made between non-renewable primary energy (PEI non-renewable; e.g. oil, gas, coal, uranium) and renewable primary energy (PEI renewable; e.g. electricity from wind power) [20]. In contrast to the environmental effects of emissions resulting from a material’s use described above (outputrelated), primary energy consumption is an input-related impact category: the environmental impact of consuming limited resources (in this case energy resources) [21]. Using a product’s calorific value, e.g. through thermal recycling, reduces the consumption of other primary energy sources for producing electricity and heat. This saving can be credited to the product in question as reducing its primary energy content. Primary energy consumption is measured in megajoules (MJ) [22]. Depletion of abiotic resources The abiotic resources depletion (ADP) impact category describes the consumption and depletion of non-renewable mineral resources in contrast to renewable resources from the biosphere. A distinction is made between fossil fuels (ADP fossil fuels) and other minerals (ADP elements). For fossil fuels, the lower calorific value is used as the characterisation factor, so it is assumed that these materials are interchangeable and that the rate of depletion is the same for all fossil fuels. In assessing the other mineral resources, the amount existing worldwide (ultimate reserve) is taken into account, regardless of its technical or economic recoverability and annual extraction rates [23]. Life-cycle assessment data on construction products

Drafting a life-cycle assessment for a product is a complex process usually carried out by specialists for manufacturers, with the prod-

uct’s environmental characteristics subsequently communicated through various environmental labels and comprehensive reports. The data compiled is collected in various databanks and made available to planners in a standardised form. Specific life-cycle assessment product data usually refers to a manufacturer’s specific product that was produced using a certain process within a defined period at a particular production location (Fig. C 4.5). As well as product-specific life cycle assessments, generic data is also available, which usually consists of average values or representative individual values and often refers to a country or region and defined period. Generic data can take various production processes into account (in accordance with their actual distribution in the production process), but it is also based on specific analyses of individual plants and processes. Generic data is used for upstream processes that are not reassessed in a product-specific life-cycle assessment (e.g. energy generation and transport processes, production of intermediate products). It can also be used for estimates during planning if information on the actual product to be used or other product-specific data is not yet available [24]. Environmental labelling

Various labelling systems have been introduced to communicate a product’s environmental characteristics, and not just in construction. The ISO 14 020 series of standards defines three different types. Type I environmental labelling, “certified ecolabels”, identify products with a particularly good environmental performance within the same product group. The requirements for a Type I environmental declaration are specific boundary values, compliance with which make a product much more environmentally friendly than its competition. The boundary values are regularly adjusted so that only a certain percentage of products in a product group, namely the best, bear the seal (“best in class”). Compliance with boundary values is established by appropriate measurements,

Life-cycle assessments for windows and exterior doors

Structural component Reference unit [m2]

Greenhouse potential (GWP)

Ozone depletion potential (ODP)

Acidification Ozone potential creation poten(AP) tial (POCP)

Eutrophication potential (EP)

[kg CO2 equiv.] [kg R11 equiv.] [kg C2H4 equiv.] [kg SO2 equiv.] [kg PO43- equiv.] Doors

Primary energy use non-renewable (PEI n. renew.)

Primary energy use renewable (PEI renew.)

Primary energy use total (PEI total)

[MJ]

[MJ]

[MJ]

Multifunctional doors Multifunctional steel doors (Hörmann)

Manufacture End of life Sum

123.10 -49.28 73.82

0.000041 -0.000003 0.000039

0.05220 -0.02300 0.02920

0.37410 -0.17540 0.20

0.03670 -0.00380 0.03

1,651.00 -1,045.00 606.00

58.58 -28.44 30.14

1,709.58 -1,073.44 636.14

Multifunctional steel doors (Teckentrup)

Manufacture Use Subsequent use Recycling potential Sum

220.58 7.98 28.51 -47.09 209.98

0.000024 0.000000 -0.000001 0.000000 0.000025

0.05700 0.00310 0.00580 -0.02000 0.04590

0.32000 0.02200 0.00830 -0.13470 0.21560

0.03100 0.00300 0.04500 -0.01370 0.06530

1,510.38 133.59 -88.28 -636.70 918.99

98.24 5.72 -2.36 -8.86 92.74

1,608.62 139.31 -90.64 -645.56 1,011.73

Manufacture Use Subsequent use Recycling potential Sum

136.16 21.37 2.08 -45.17 114.44

0.000015 0.000002 0.000000 0.000000 0.000017

0.05600 0.00739 0.00016 -0.03200 0.03155

0.50100 0.10000 0.00562 -0.25000 0.35662

0.05200 0.01400 0.00052 0.00005 0.06656

1,980.36 352.64 29.52 -763.19 1,599.33

165.34 32.90 18.44 -1.01 215.67

2,145.70 385.54 47.96 -764.20 1,815.00

Manufacture Use Subsequent use Recycling potential Sum

49.76 552.41 1.98 -22.29 581.86

0.000002 0.000002 0.000000 0.000000 0.000003

0.04000 0.10000 -0.00019 -0.01000 0.12982

0.50000 0.73000 0.00962 -0.27000 0.96962

0.04000 0.09000 0.00080 -0.01000 0.12080

1,386.85 9,986.60 34.80 -624.00 10,784.25

332.60 75.20 4.85 -100.34 312.31

1,719.45 10,061.80 39.65 -724.34 11,096.56

Manufacture Use Subsequent use Recycling potential Sum

132.74 9.66 0.13 -68.55 73.98

0.000009 0.000000 0.000000 -0.000003 0.000006

0.06200 0.00526 0.00000 -0.03200 0.03526

0.70000 0.00623 0.00070 -0.35000 0.35693

0.03700 0.00251 0.00004 -0.00203 0.03752

1,822.66 176.24 0.45 -977.21 1,022.14

283.83 6.28 0.00 -229.81 60.30

2,106.49 182.52 0.45 -1,207.02 1,082.44

Steel interior doors (Hörmann, Brandis)

Manufacture Use Subsequent use Recycling potential Sum

40.54 2.33 0.07 -11.32 31.62

0.000002 0.000000 0.000000 0.000000 0.000002

0.01800 0.00170 0.00002 -0.00596 0.01376

0.19000 0.00642 0.00038 -0.04500 0.15180

0.01400 0.00058 0.00002 0.00270 0.01730

465.23 62.94 0.18 -233.17 295.18

64.36 0.87 0.00 -2.83 62.40

529.59 63.81 0.18 -236.00 357.58

Aluminium windows (Hueck)

Manufacture Use Subsequent use Recycling potential Sum

157.00 590.00 13.00 -119.00 641.00

0.00001 0.00003 0.00000 -0.00010 -0.00005

0.04820 0.06730 0.00100 -0.01720 0.09930

0.73000 0.63500 0.01200 -0.57300 0.80400

0.05580 0.09330 0.00220 -0.03750 0.11380

2,253.00 9,796.00 258.00 -1,510.00 10,797.00

397 37 1 -356 79

2,650.00 9,833.00 259.00 -1,866.00 10,876.00

Wood-frame windows (Hama Alu + Holzbauwerk)

Manufacture Use Subsequent use Recycling potential Sum

39.00 594.00 29.00 -41.00 621.00

0.00001 0.00000 0.00000 0.00000 0.00001

0.03050 0.10560 0.00060 0.00140 0.13810

0.26000 0.67200 0.00700 -0.15500 0.78400

0.03450 0.09330 0.00210 -0.01850 0.11140

1,089.00 9,901.00 16.00 -514.00 10,492.00

436 35 0 -19 452

1,525.00 9,936.00 16.00 -533.00 10,944.00

Wood-metal windows / sliding doors (Wiegand Fensterbau)

Manufacture Use Subsequent use Recycling potential Sum

54.00 543.02 1.76 -22.15 576.63

0.00000 0.00000 0.00000 0.00000 0.00000

0.03000 0.10000 -0.00017 -0.01000 0.11984

0.45000 0.69000 0.00855 -0.25000 0.89855

0.04000 0.08000 0.00071 -0.01000 0.11071

1,209.10 9,832.21 30.91 -562.97 10,509.25

318 68 4 -92 298

1,526.65 9,900.44 35.22 -655.38 10,806.93

Wood-metal windows (Wiegand Fensterbau)

Manufacture Use Subsequent use Recycling potential Sum

66.59 404.62 1.76 -22.96 450.01

0.00000 0.00000 0.00000 0.00000 0.00000

0.04000 0.08000 -0.00017 -0.02000 0.09984

0.51000 0.58000 0.00855 -0.33000 0.76855

0.05000 0.07000 0.00071 -0.02000 0.10071

1,519.04 7,325.21 30.91 -714.22 8,160.94

399 58 4 -115 347

1,918.05 7,383.54 35.22 -828.88 8,507.93

Passive house wood-metal windows (Wiegand Fensterbau)

Manufacture Use Subsequent use Recycling potential Sum

58.78 404.62 1.76 -25.77 439.39

0.00000 0.00000 0.00000 .00000 0.00000

0.04000 0.08000 -0.00017 -0.02000 0.09984

0.49000 0.58000 0.00855 -0.31000 0.76855

0.04000 0.07000 0.00071 -0.02000 0.09071

1,296.01 7,325.21 30.91 -667.60 7,984.53

400 58 4 -111 352

1,695.79 7,383.54 35.22 -778.45 8,336.10

Plastic-frame windows (Juchheim-Börner)

Manufacture Use Subsequent use Recycling potential Sum

85.00 583.00 14.00 -63.00 619.00

0.00001 0.00000 0.00000 0.00000 0.00001

0.03340 0.06470 0.00380 -0.01220 0.08970

0.33200 0.60800 0.01800 -0.26700 0.69100

0.03840 0.09080 0.00270 -0.02690 0.10500

1,393.00 9,653.00 200.00 -1,000.00 10,246.00

46 26 13 -20 65

1,439.00 9,679.00 213.00 -1,020.00 10,311.00

Fire protection doors Fire protection doors and steel doors (Ei2 Protector) Sliding doors Wood-metal lift-up sliding doors (Wiegand Fensterbau) House doors Steel house doors in the ThermoPro series (Hörmann, Brandis) Interior doors

Windows

Wood-metal windows

C 4.5

211

Life-cycle assessments for windows and exterior doors

Pine 34.7 %

Wood /Aluminium 3.4 % Wood 16.7 %

Spruce 12.1% Aluminium 19.0 %

Meranti 38.4 % Plastic 60.9 %

Larch 6.3 %

Other 3.2 % C 4.6

which are confirmed by independent third parties. Type I environmental labels always refer only to individual environmental performance and do not provide comprehensive information on a product’s environmental impact over its entire life cycle. Well-known Type I environmental labels are the Blaue Engel and European eco-label (EU Flower), which are issued by the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (Bundesministerium für Umwelt, Naturschutz, Bau und Reaktorsicherheit – BMUB) and the German Institute for Quality Assurance and Certification (RAL Deutsches Institut für Gütesicherung und Kennzeichnung). Another example of such labelling is the FSC seal for wood products, which is issued by the Forest Stewardship Council, an international non-profit organisation [25]. Type I environmental labels are designed mainly to communicate a product’s environmental properties to end users but can also be used in business-to-business communications [26]. Type II environmental labels, “self-declared environmental claims”, are descriptions of a product’s environmental characteristics issued by manufacturers on their own authority. Their declarations must take into account the restrictions prescribed in DIN 14 021 but do not have to be reviewed by an independent third party [27]. Type III Environmental Product Declarations (EPD) describe products’ environmental characteristics systematically and comprehensively but without evaluating them. They are drafted by product manufacturers based on a life-cycle assessment of the product and submitted to recognised programme operators. They also record other productspecific indicators (e.g. interior air pollution). For this kind of declaration, an independent third party reviews not the results of individual measurements but compliance with the product category rules (PCR) for the product description [28]. Environmental Product Declarations are developed and used in Environmental Product Dec-

212

Tsuga 2.1%

Oak 3.2%

C 4.7

laration programmes. National programme operators (which may be one or more companies, associations, government agencies and departments or scientific institutions etc.) run the programmes [29]. In Germany, the Institut Bauen und Umwelt (IBU) and Institut für Fenstertechnik (ift) Rosenheim (for doors and windows) are recognised Environmental Product Declaration programme operators for construction products. A consortium of European programme operators (ECO Platform) is seeking to harmonise individual programmes with the goal of reducing the cost and effort involved for product manufacturers who sell their products in several countries and currently have to draft a separate EPD for each country [30]. Data sources

There is currently no complete collection of all available life-cycle assessment data on construction products. Product-specific data from Environmental Product Declaration programmes is made available by national programme operators (in Germany the IBU and ift) in their own databases, usually as a download of pdf documents, or it can be obtained directly from product manufacturers. Life-cycle assessment data is also part of continuing construction materials databases used in the sustainability certification of buildings. Generic life-cycle assessment data on construction products is published in the “Ökobau.dat” database of the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB). As well as generic data, specific Environmental Product Declaration data for particular construction products is recorded in annual updates. In addition to the various public and free databases, a series of more detailed data is available from commercial providers. Companies can draw up a life-cycle assessment if no such data exists, although this will remain, not least for financial reasons, the exception rather than the rule for the purposes of planning processes.

Life-cycle assessment data in planning Life-cycle assessment data from Environmental Product Declarations can be used in planning to compare the environmental impact of different products or structures and can optimise planning. Information must always be compared in the context of a particular building so as to take into account all the connections and effects of a product on it. Comparisons of individual structural elements or materials can be made if the following prerequisites are fulfilled for the elements to be compared: • They have the same functional requirements. • The amounts, processes and phases not taken into account in the life cycle and technical and environmental qualities should be the same. • The influence of the products on building operations should be taken into account [31]. Openings and windows in building envelopes can have a major influence on building operations. Different U-values or g-values of competing products may increase heating or cooling needs, which must then be met over the building’s entire period of use. Differences in environmental impact resulting from changes to building operations can be much higher than differences resulting from the manufacture, maintenance and disposal of various products. On the other hand, differences between products can be insignificant in the context of a building [32]. Small components such as window handles, which have a very small mass compared with the main structure, can still significantly optimise environmental performance (if product A has an 80 % lower environmental impact than product B, for example) or may have no influence at all on the environmental quality of the building as a whole. Window manufacture: raw materials and basic materials

The manufacture of construction products often has a bigger environmental impact than their maintenance and disposal. Falling energy

Plastic, aluminium, wood and wood-aluminium structures are mainly used as frame materials (Fig. C 4.6). Due to poor thermal properties, steel profiles no longer have a notable market share in total EU production (see “Types of windows, frame profiles and joining techniques”, p. 99ff.). Plastics In 2012, plastic had the biggest market share of all frame materials in Europe, at over 60 % [33]. These were mainly extruded polyvinylchloride (PVC-U) frames. Other plastics, such as polypropylene (PP), Acrylonitrile styrene acrylate (ASA), polyurethane (PUR) and fibreglass-reinforced plastics, play only a secondary role. Plastic frames with better thermal insulation are made with several chambers and often reinforced on the inside with steel profiles to increase their load-bearing capacity and make bigger windows possible [34]. Additions and “modifiers” can be used to adapt PVC window frames to climatic variables such as UV radiation or low temperatures. The “modifiers” are other plastic compounds (e.g. polyacrylate) added to the PVC-U during manufacture [35]. The emissions-related environmental impact of the manufacture of PVC frames lies between that of wood and aluminium frames in all impact categories – as does its total primary energy consumption, the sum of non-renewable and renewable primary energy it consumes. Like most other plastics, PVC is made of oil, which is an entirely synthetic non-renewable resource. In the long term, lower levels of oil extraction and higher oil prices are likely. The competing use of oil as a source of energy is also problematic, although only 4 % of global oil production is used for manufacturing plastics. In an energy study carried out in 2012, the Federal Institute for Geosciences and Natural Resources (Bundesanstalt für Geowissenschaften und Rohstoffe – BGR) forecast that “Oil is the only non-renewable energy resource for which increasing demand will not be able to be met in coming decades” [36]. The use of additives in PVC and the replacement of interior steel

Aluminium Aluminium windows are made of extruded aluminium profiles. They are now manufactured as composite elements containing plastic or wooden elements to limit heat loss. In almost all environmental impact categories, aluminium profiles have the greatest impact per metre of profile (with the exception of photochemical ozone creation potential). This is due to the energy-intensive production of aluminium from bauxite and is reflected in comparatively high total primary energy consumption. Aluminium, however, can be recycled, which requires much less energy than primary manufacture. One challenge is the clean separation of aluminium from built-in plastic or timber materials. Aluminium is the most common metal in the Earth’s crust, so it is less likely than other metals to run out. Given current options for recycling it, the supply of aluminium is now regarded as limitless [37]. Wood Wooden window frames are made of solid timber or glued plywood. Conifer woods, such as pine, spruce, larch, tsuga, Oregon pine and fir, and deciduous woods such as meranti, oak, iroko, mahogany and makore (Fig. C 4.7) are used. Wooden window-frame manufacture has the lowest environmental impact in all emissions-related impact categories, with the sole exception of photochemical ozone creation potential, whose higher values probably result from the glue used. Less primary energy is consumed to make them than to make PVC or aluminium profiles, and a large part of that primary energy is renewable. It should be noted that the varnishing and painting that timber requires can cause further emissions and other environmental effects. Timber products’ origins and extraction can also be problematic. Almost 40 % of the wood used in wooden-frame windows is imported tropical timber, especially meranti from SouthEast Asia [38]. It is assumed that over 70 % of this timber comes from illegal logging, not sustainable forestry [39]. This means that stocks of high-quality dark red meranti (density > 0.55g/cm3), which is especially suitable for window construction, are declining steeply, so this theoretically renewable raw material may no longer be available in sufficient quantities

C 4.6 C 4.7

C 4.8

Proportion of various window and door-frame materials of total production in the EU Proportion of different types of deciduous and coniferous woods used in the manufacture of wooden window frames in the EU Development of acidification, greenhouse and photochemical ozone potential over 100 years

2.5

2.0

1.5

1.0

0.5

0 10

20

30

40

50

60 70 80 90 100 Useful service life [a]

0 10

20

30

40

50

60 70 80 90 100 Useful service life [a]

0 10

20

30

40

50

60 70 80 90 100 Useful service life [a]

0 Greenhouse potential [kg CO2 equiv.]

Frame materials

profiles with fibreglass-reinforced plastic should be viewed critically in terms of subsequent recycling because it makes clean separation and recycling more difficult or even impossible.

600 500

400

300 200

100 0

Photochemical ozone creation potential [kg C2H4 equiv.]

requirements in operating buildings mean that the environmental impact of building construction is becoming increasingly important. Optimising the environmental quality of buildings begins with selecting products, raw materials and basic materials. The environmental effects of emissions and energy and resources consumption in manufacture and the possibility of dismantling and recycling a product at the end of its life cycle must all be considered. Windows and doors consist of several components and are made of different basic materials. These are described below in terms of their environmental impact, energy consumption in manufacture, long-term availability and recycling potential.

Acidification potential [kg SO2 equiv.]

Life-cycle assessments for windows and exterior doors

0.6

0.5

0.4

0.3

0.2

0.1

0

Wood-frame window (exposed to heavy loads) Wood-frame window (average) Wood-frame window (exposed to light loads) PVC-frame window (exposed to heavy loads) PVC-frame window (average) PVC-frame window (exposed to light loads) Aluminium-frame window (exposed to heavy loads) Aluminium-frame window (average) Aluminium-frame window (exposed to light loads) C 4.8

213

[%]

Life-cycle assessments for windows and exterior doors

30

20

10

0

-10 GWP

ODP

POCP

and quality in future. Timber industry and supply chain certification is designed to prevent this malpractice. Wood certified with the “Forest Stewardship Council” seal comes from sustainable timber extraction, which as well as promoting sustainable forestry also addresses the interests and ownership claims of local people and the protection of biodiversity. Environmental groups, however, have criticised the fact that plantations on cleared virgin forest have also been awarded certificates, so local wood should be preferred to tropical timber. Transport miles play only a secondary role in frames’ environmental impact because shipping transport is usually quite efficient, i.e. has a low environmental impact per tonne of wood shipped. Glazing

Two different types of glass are mainly used in construction; lime-soda glass for most standard applications and borosilicate glass for windows that need to be less sensitive to changes in temperature and highly resistant to chemicals. Both kinds of glass are manufactured using the float glass process (see “Glass as a filling material”, p 86ff.). Borosilicate glass can also be poured. Glass is made by melting quartz sand (silicon oxide) and adding metal oxides and sodium carbonate as a flux agent, as well as calcium carbonate. The process requires temperatures of a 1,000 to 1,600 °C and is chemically comparatively simple [40]. Panes can be covered with various functional coatings during or after manufacture. Low-absorption silver-metal oxides can improve thermal insulation and sun protection (see “Coatings”, p. 89ff.) [41]. Coating systems (several coatings are usually combined) can reach a thickness of around 0.1 mm [42], while individual layers are 10 to 100 nm thick, which for a silver coating means a ratio of 0.010 to 0.100 g/m2. Despite the high temperatures it requires, the environmental impact of and primary energy required for manufacturing flat glass are low compared with that for transparent plastic panels of the same thickness and translucency. Glass is also denser than most plastics. Comparisons with other materials in terms of

214

AP

EP

PEI n. renew.

PEI renew. C 4.9

their translucency, thermal conductivity etc. are not very useful because of their very different properties. Quartz sand, the basic material of glass manufacture, is available in a practically unlimited supply on Earth. The sodium carbonate used to reduce its melting temperature can be obtained directly from the elements natrium and oxygen, so its supply is also almost limitless. The calcium carbonate used to improve glass’s hardness and resistance to chemicals is one of the commonest chemical compounds on Earth, so a shortage of its main raw materials is not possible. There may, however, be shortages of and price increases for the metal oxides added to glass (iron oxide, magnesium oxide, aluminium oxide) and those used in different functional coatings (e.g. low-E coatings of gold, silver or copper) [43] in the medium term [44]. Fillings in spaces between windowpanes

Spaces between the panes of insulating glazing windows are filled with inert gases to improve thermal insulation properties (see “Gas filling in the space between panes”, p. 92f). Argon or krypton is usually used, or more rarely xenon [45]. Inert gases are obtained by air liquefaction, using the Hampson-Linde cycle during nitrogen and oxygen production. They are energy-intensive to produce, with the resulting environmental effects. Compared with argon and krypton, the additional energy consumed in manufacturing xenon exceeds any subsequent heating energy savings. The manufacturing process makes reserves of these gases easily accessible, so a shortage is unlikely [46].

desiccant on the inside (to prevent condensation). A second seal is provided along the outside of the insulating pane of glass and polysulphide, polyurethane or silicon adhesive applied [47]. Aluminium and steel spacers are subject to the same environmental impacts and availability as their basic materials described above. The plastics and sealants used in bonded edges are oil-based. The way they are used in construction means that materials in different material groups are fused with each other, making subsequent recycling more difficult.

Usage – the service life and life-cycle assessments of buildings The environmental impact of a product’s utilisation phase depends largely on its durability or service life over the period under review. A short service life makes frequent replacement necessary, i.e. disposal and repeated manufacture with the resulting emissions and energy and resource consumption. If products are part of an overarching system, e.g. a construction product in a building, their influence on the entire system throughout the utilisation phase must be taken into account. For openings and windows, this is the influence on heat losses and solar heat input during utilisation. The service life of different window structures and the relevant influential parameters are described in more detail in the section on “Durability and service life” (p. 82f. and Fig. B 1.74, p. 84 and B 1.75, p. 85).

Bonded edge

A bonded edge is a linear spacer between the edges of panes in insulating windows with two or more panes of glass. It geometrically forms the space between the panes and seals it (see “Spacers and edge bonds, ‘warm edge’ ”, p. 92ff.). The bonded edge usually consists of a metal or plastic spacer with a butyl seal that seals the space between the panes on the inside and sometimes a

C 4.9

Proportion of openings and windows in a building’s life-cycle assessment in different impact categories. Results of a non-representative evaluation of building life-cycle assessments of detached and semi-detached houses built using different methods with normal window area. Dark areas mark the 25 % –75 %-quantile. C 4.10 Recycling potential for structural elements and building materials C 4.11 Co-extruded PVC frame profile with a recyclate core (darker) and primary material casing

Life-cycle assessments for windows and exterior doors

Recycling

Disposal

Reuse of a structural component

Structural component that meets the technical / legal standards for new buildings

Structural component that meets the technical / legal standards for existing buildings

Structural component that is technically functional but no longer state of the art

–

Material recycling

Too technical /costeffective comparable product

To a high-quality raw material with high market value

To a high-quality building material with a low market value

Technically possible but not cost-effective; downcycling

Thermal recycling

Does not cause any waste-specific pollutants; high calorific value

Unproblematic in large plants; medium calorific value

In waste incineration plant; low calorific value

After preparation

Dumping (waste dump)

Composting or humification

In construction waste or inert matter landfill

In construction waste landfill, but not unproblematic

In a large-scale waste dump or in residual materials landfill; emissions possible C 4.10

Maintenance of doors and windows

The maintenance and upkeep doors and windows require depend on the materials they consist of. Aluminium and plastic frame profiles do not usually require much maintenance, but wooden window frames must be glazed or painted at regular intervals. The length of time between maintenance and the frequency of its performance depends on the specific installation situation. Although coatings of glaze and paint have only a comparatively small mass, the increased maintenance they require can influence individual impact categories in their life-cycle assessment (Fig. C 4.8, p. 213).

The influence of doors and windows on a building’s life-cycle assessment The period under review and the service life of building products will have a major influence on the results of life-cycle assessment studies of buildings. The length of the period reviewed should be carefully weighed up and anomalous periods investigated in the form of scenario analyses. Sustainability certification systems like the DGNB or BNB base their life-cycle assessments of buildings on observation periods of 50 years. Openings and windows have little influence on the life-cycle assessments of building construction (manufacture, maintenance, disposal) compared with their influence on overall construction. Depending on the impact category and construction type, it can range from 0 to 20 % for detached and semi-detached houses with a normal area of window surface (Fig. C 4.9). In contrast to their influence on life-cycle assessments of building construction, openings and windows can have a much greater impact on the life-cycle assessments of building operations. Large amounts of heat are often lost through openings and windows, compared with the remaining building envelope surface, so they are responsible for a major part of heating energy requirements. On the other hand, the use of the solar gains they offer

can help reduce heating demands in winter. Unshaded openings can make it necessary to cool buildings in summer. The proportion of openings and windows in the life-cycle assessments of building operations, and therefore in their overall energy balance, depends on many factors, such as the quality of the rest of the building envelope, usage, and the heating and cooling system chosen (see “Size and layout of openings”, p. 182ff and “Technical building components in and around windows”, p. 198ff.). End of life: recycling doors and windows

Reusing or recycling building elements and construction materials at the end of their life cycles reduces resources consumption. A distinction can be made between the reuse of structural elements, raw materials recycling, i.e. breaking them down into their constituent elements, thermal recycling (use of energy from burning construction materials) and the dumping of waste in landfill. Thermal recycling reuses the energy stored in the material, so the material resource is then no longer available, and, like dumping waste, is not considered true recycling. (Fig. C 4.10) Various methods of disposing of door and window components described are shown below. A distinction should be made between currently common processes and processes that are technically possible but currently not used, mainly for economic reasons. Only standard market processes currently in use can be taken into account in Environmental Product Declarations and building life-cycle assessments as part of sustainability certification, so they represent the status quo, not possible future scenarios. As the need for resources increases, especially in emerging economies, and available global reserves become scarcer and raw material prices grow accordingly, recycling systems that are currently not economically viable will become established in the medium term. The reuse of windows Reusing structural elements is the optimum environmental solution and saves resources if the element still meets technical and legal

C 4.11

requirements. Structural components are reused after either retrofitting where they were originally installed (restoration) or collection, possibly repair, and then installation in another building (Fig. C 4.4, p. 210). In Germany, various “building materials exchanges” have merged to form a national structural components network [48] where used but functional structural elements are offered for sale in a catalogue and can be viewed in a warehouse and purchased. The size and value of window and door elements makes them particular suitable for trading in building materials exchanges. Old windows and doors often no longer comply with legal regulations, such as the German Energy Saving Ordinance (Energieeinsparverordnung – EnEV), so they often have to be either retrofitted to make them more energy-efficient (e.g. by replacing glazing) or used in areas where the Energy Saving Ordinance does not apply (e.g. in unheated rooms, listed historic buildings or for export abroad). The total proportion of directly reused PVC windows of all accumulated waste is 7.6 % [49]. Recycling window components The recycling of building materials depends on a range of preconditions. The material must be fundamentally recyclable and appropriate technical processes must be available to separate the building material from other materials and reduce it to its constituents. The recycled material must also be reusable. Recycled material is competing with primary material in terms of its physical and chemical properties. Depending on the application in question, it could perhaps be slightly lower quality to a negligible extent or be compensated for by lower cost, compared with primary products. Recycling must be economically feasible. As well as the technical effort and energy expended, the available amount of waste and the investment and time involved in collecting it are crucial. Products that are not available in significant quantities in one place or are costly and difficult to extract can make collection and recycling uneconomic. This can be the case with a wide range of similar products that undergo different recyc-

215

Life-cycle assessments for windows and exterior doors

ling processes, e.g. plastics. Precise product labelling makes collection and sorting easier.

Compact plastic waste (clean, sorted)

Shredding

Various techniques are now used to dispose of frame materials. Collection systems for PVC frames have now been established in Europe. Frames are pre-sorted to separate out impurities (e.g. foils) and the material is crushed and washed. It is then graded according to compatibility and into homogeneous groups. Additives (compatibilisers, stabilisers, possibly fillers and dyes) are added to the ground material and it is compressed and homogenised by fusing it in an extruder (Fig. C 4.12). It is usually extruded to make PVC granulate, which is easy to store and transport for further use [50]. Granulate can be used to produce new window frames or other PVC structural components [51]. Recyclates are often of lower quality than primary products [52], so recyclate and primary material may be co-extruded to make new PVC profiles, with the inside of the recyclate window frame profile encased in a casing made of plastic in its primary form (Fig. C 4.11, p. 215).

Metal separation (magnetic, inductive)

Fine grinding (cutting mill) Wind winnowing or hydrocycloning

Waste (metal, paper, foil and other plastics)

Ground material

Additive

Homogenise, plasticise, melt filtration (screw extruder) Strand (or profile) Strand granulate Regranulate C 4.12

Demolition

Disposal companies

Residential construction

8535 t

6400 t

2120 t

23 900 t

Window manufacturers

40 955 t Amount of PVC waste 2012

2900 t re-used window frames

Identifiable and available amount 26 640 t Material recycling 25 096 t

Not identifiable or available Energy recovery 12 959 t

11 415 t

38 055 t Gross potential

C 4.13

216

In 2012, 54 % of all PVC waste underwent material recycling (Fig. C 4.13) [53]. As well as saving oil, recycling also avoids the thermal recycling of PVC, which releases corrosive hydrogen chloride that can damage waste incinerators and release dioxins. The process cannot be repeated indefinitely, due to the increasingly low quality of the recyclate, so chemical recycling, which breaks plastics down into chlorinated hydrocarbons or synthesis gas, will become increasingly important in future. A building’s life-cycle assessment is usually based on thermal recycling. The energy (power and heat) it releases is accredited as saved production energy from other energy sources. Manufacturers’ Environmental Product Declarations take the use of recycled materials in production into account. There are also collection systems for recycling aluminium profiles. Aluminium scrap is crushed, other metals are separated from it and it is further separated into different alloys. This is necessary because alloy elements cannot be removed by smelting. The aluminium is then melted down and can be poured again [54]. The life-cycle assessment indicates aluminium recycling in the form of “recycling potential”. Since the metal’s previous and subsequent use is generally unknown and so cannot be part of its life cycle, the potentially avoided production of primary aluminium from bauxite is credited to its environmental impact in disposal. This calculation, however, is based on average mixtures of primary and secondary metal that can differ greatly in individual cases. Wooden frames are disposed of in accordance with the specifications of the Waste Wood

Ordinance (AltholzV), which defines four different categories and waste wood contaminated with polychlorinated biphenyls (PCBs). Frames can be disposed of in various ways depending on their origins. Timber-frame windows made after 1990 are classified in waste wood class II. They can be used in material recycling (e.g. to manufacture new chipboard) and thermal recycling. Older windows are classified in waste wood class IV and can be thermally recycled. Windows contaminated with PCBs must be disposed of in separate facilities [55]. Life-cycle assessments treat the thermal recycling of wood like that of plastics. When panes of insulating glass are disposed of, their different admixtures and coatings prevent effective material recycling from turning them into an equivalent base product. While 85 % of container glass is recycled [56], the high-quality demands on float glass mean that only small amounts of plate glass granulate can be reused to manufacture new plate glass, almost exclusively plate glass waste from its production and cutting [57], although in Germany a special network has been set up to collect, process and recycle plate glass. Most of this waste is used to make container glass, cast glass, insulating fibre, glass bricks, foam glass and glass fibre [58]. No current figures are available on the actual amounts of recycled plate glass and its recycling quota, because, in contrast to container glass, there are no legal requirements to record the amounts and only a few players in the market [59]. Bonded edges, which are made of various materials and adhered to the panes, must also be separated before panes of insulating glass can be disposed of. Life-cycle assessments for buildings assume that panes of insulating glass are disposed of in landfill. The use of production waste in manufacture is taken into account in certain Environment Product Declarations. The inert gases now used as insulation in the space between the panes are unproblematic in their environmental impact in the disposal of panes of insulating glass. Older soundproof windows, however, may be filled with sulphur hexafluoride, an extremely potent greenhouse gas. 1 kg of sulphur hexafluoride makes the same contribution to the greenhouse effect as 23,600 kg of CO2 [60], so these windows must be disposed of by specialist companies and the gas contained.

Environmental impact and window size The environmental effects of windows depend on the environmental impact of individual window components. The proportion of components in a window and their contribution to environmental impact also changes with the window’s size, with environmental effects

Life-cycle assessments for windows and exterior doors

Frame profile – wood Frame profile – aluminium

Frame profile – PVC

Acidification potential [kg SO2 equiv./m2 window]

2.5

2.0

1.5

1.0

0.5

0 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 Side length of a square window [m]

Greenhouse potential [kg CO2 equiv./m2 window]

Notes: [1] DIN EN ISO 14 040:2009, p. 4 [2] ibid., p. 36 [3] ibid., p. 4 [4] Directive (EU) No. 305/2011 D [5] DIN EN ISO 14 040:2009, p. 15 [6] Klöpffer, Walter; Grahl, Birgit: Ökobilanz (LCA). Ein Leitfaden für Ausbildung und Beruf. Weinheim 2009, p. 30ff. [7] Hegger, Manfred et al.: Baustoff Atlas. Munich 2005, p. 98 [8] DIN EN ISO 14 040:2009 [9] ibid., p. 27 [10] DIN EN 15 804:2012, p. 30f. [11] As for Note 6, p. 197ff. [12] DIN EN ISO 14 044 [13] As for Note 6, p. 216 [14] As for Note 1, p. 31ff. [15] Guinée, Jeroen B. (ed.): Handbook on Life Cycle Assessment. Operational Guide to the ISO Standards. Dordrecht 2004, p. 75 [16] ibid. [17] ibid., p. 80 [18] ibid., p. 81 [19] ibid., p. 82 [20] As for Note 7, p. 99 [21] As for Note 6, p. 229ff. [22] As for Note 7, p. 99 [23] Ministerie van Verkeer en Waterstaat: Dienst Wegen Waterbouwkunde: Abiotic resource depletion in LCA. Leiden 2002 [24] As for Note 6, p. 133ff. [25] Veith, Jürgen; Lerch, Patrick: Gesundheit und Umweltschutz bei Bauprodukten. Die europäische Normung zur Bauprodukten-Richtlinie. Stuttgart 2008, p. 69ff. [26] EcoSMEs: Zertifizierte Ökolabel und andere ISOKennzeichnungen. www.ecosmes.net/cm/nav Contents?l=DE&navID=ecoLabels&subNavID= 1&pagID=1 [27] As for Note 25, p. 63 [28] ibid., p. 73f. [29] DIN EN ISO 14 025:2010, p. 9 [30] ECO platform: The mission. Objectives and added value of the ECO platform. www.eco-platform.org/ the-mission.html [31] DIN EN 15 804:2012, p. 15 [32] ibid. [33] www.baulinks.de/webplugin/2013/0460.php4 [34] Knippers, Jan et al.: Atlas Kunststoffe + Membranen. Werkstoffe und Halbzeuge, Formfindung und Konstruktion. Munich, 2010, p. 82f. [35] Wendehorst, Reinhard: Baustoffkunde. Hanover 2004, p. 782f.

[36] Bundesanstalt für Geowissenschaften und Rohstoffe (pub.): Dera Rohstoffinformationen. Energiestudie 2012. Reserven, Ressourcen und Verfügbarkeit von Energierohstoffen. Hanover, 2012, p. 18 [37] Rheinisch-Westfälisches Institut für Wirtschaftsforschung: Trends der Angebots- und Nachfragesituation bei mineralischen Rohstoffen. Essen n. y., p. 73 [38] Bundesverband ProHolzfenster e. V.: Holzarten für den Fensterbau. 2014. www.proholzfenster.de / 43.html [39] Royal Institute of International Affairs: Controlling the international trade in illegally logged timber and wood products. London 2002 [40] Achilles, Andreas u. a.: Glasklar. Produkte und Technologien zum Einsatz von Glas in der Architektur. Munich 2003, p. 12ff. [41] ibid., p. 33ff. [42] ibid., p. 82 [43] ibid., p. 34 [44] Wuppertal Institut für Klima, Umwelt, Energie GmbH 2009, p. 14f. [45] As for Note 40, p. 53 [46] Forum Nachhaltiges Bauen: Wärmeschutzgläser – Ökobilanz. 2014. www.nachhaltiges-bauen.de /baustoffe / Wärmeschutzgläser [47] As for Note 40, p. 51 [48] www.bauteilnetz.de [49] Rewindo GmbH: 10 Jahre Rewindo. Kunststofffenster-Recycling in Zahlen. Bonn 2012, p. 5. www.rewindo.de/rewindo-downloads/downloads/ Rewindo_Mengenstromnachweis_KU_2012.pdf [50] Martens, Hans: Recyclingtechnik. Fachbuch für Lehre und Praxis. Heidelberg 2011, p. 172ff. [51] VEKA Umwelttechnik GmbH: PVC-Granulate von VEKA. 2014. www.veka-ut.de/index.php?id=52 [52] As for Note 50, p. 171 [53] As for Note 49, p. 6 [54] As for Note 50, p. 94ff. [55] Bundesverband ProHolzfenster e. V.: Presseinformation “Kein Sondermüll – alte Holzfenster sind Biomasse”. Berlin 2003. www.proholzfenster.de/ 140.html [56] Bundesverband Glasindustrie e. V., Fachgruppe Behälterglasindustrie: Recycling figures. 2014. www.glasaktuell.de/zahlen-fakten/recycling-zahlen [57] As for Note 50, p. 209ff. [58] bvse-Bundesverband Sekundärrohstoffe und Entsorgung e. V.: Flachglasrecycling. 2014. www.bvse.de/342/498/9__Flachglasrecycling [59] Gesellschaft für Innovationsforschung und Beratung mbH: Die wirtschaftliche Bedeutung der Recyclingund Entsorgungsbranche in Deutschland. Stand, Hemmnisse, Herausforderungen. Berlin 2009, p. 118ff. [60] As for Note 15, p. 185

900 800 700 600 500 400 300 200 100 0 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 Side length of a square window [m]

C 4.12 C 4.13 C 4.14

Recycling process for PVC Recycling of PVC windows 2012 Development of Acidification Potential (AP), Greenhouse Potential (GWP) and Ozone Creation Potential (POCP) depending on frame material and window size

Ozone creation potential [kg C2H4 equiv./m2 window]

growing with each m2 of increase in window surface. For small windows in particular, components such as fittings and handles that are not scalable have a relevant influence on the windows’ overall environmental impact. The larger the window, the greater the glazing’s contribution to its overall environmental impact. A comparison shows that no frame material in all environmental impact categories has fewer effects than its competitors. The situation is different for windows of the same size over a period of more than 50 years. While windows with timber frames have the least environmental impact on greenhouse potential, windows with aluminium frames have the least environmental impact in the categories of acidification potential and photochemical ozone formation potential. Differences between frame materials vary depending on their impact category (Fig. C 4.14).

0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 Side length of a square window [m] C 4.14

217

Part D

01

Níall McLaughlin Architects, Student accommodation in Oxford (GB)

220

02

Bucher-Beholz Architekten, Terrace house in Munich (D)

222

03

Miller & Maranta, Hotel in the Altes Hospiz on St. Gotthard Pass (CH)

224

04

Unterlandstättner Architekten, Detached house in Krailing (D)

227

05

DSDHA, School in Guildford (GB)

228

06

Winfried Brenne Architekten, Renovation of the Bauhaus Dessau (D)

230

07

Augustin und Frank Architekten, Home and workshop in Berlin (D)

234

08

TreStykker 2011, Exhibition pavilion in Trondheim (N)

236

09

Nickel und Wachter Architekten, Shop renovation in Bamberg (D)

237

10

Kaestle Ocker Roeder Architekten, House and jeweller's studio in Wißgoldingen (D)

238

11

Enno Schneider Architekten, District police department in Mettmann (D)

240

12

TYIN tegnestue Architects, Training centre in Sungai Penuh (RI)

242

13 Odilo Reutter, Extension to the Landesdenkmalamt (State office for monument preservation) in Esslingen (D)

244

14

Bernardo Bader, Islamic cemetery in Altach (A)

246

15

Pereda Pérez Architectos, Detached house in Villarcayo (E)

248

16

Hermann Kaufmann, Illwerke Centre Montafon in Vandans (A)

250

17

Sou Fujimoto Architects, Residence in Tokyo (J)

252

18

Baumschlager Eberle, Office building in Lustenau (A)

254

19

Bernd Liebmann, Renovation of the former workers' canteen at the Pulverfabrik Rottweil (D)

256

Hubacher + Peier Architekten und Haerle Hubacher Architekten, Renovation of the Botanical Garden hothouses in Zurich (CH)

258

Guggenbichler+Wagenstaller, Extension and improvements to the energy efficiency of the ift Rosenheim building (D)

260

22

WOHA Architects, High-rise building in Singapore (SG)

261

23

Valerio Olgiati, House in Wollerau (CH)

262

24

Francis Goetschmann Architecte, Office building conversion and extension in Geneva (CH)

264

25

TYIN tegnestue Architects, Boathouse near Aure (N)

266

26

UID Architects, House in Hiroshima (J)

268

27

Bakker & Blanc Architectes, Pavilion in Geneva (CH)

270

28

bbp: architekten bda, Renovation and conversion of a high-rise government authority building in Kiel (D)

272

29

Hawkins\Brown, Student residences in Hertfordshire (GB)

274

30

Arkitema Architects, Office building in Ballerup (DK)

276

20

21

Image D

Stairwell with perforated bronze-coloured aluminium cladding, Student residences, Hertfordshire (GB) 2011, Hawkins\Brown

Built examples in detail

219

Example 01

Sectional view Scale 1:250 Floor plan, ground floor Scale 1:750

Student accommodation Oxford, GB 2011

1

Architects: Níall McLaughlin Architects, London Project managers: Simon Bishop, Bev Dockray Structural engineering: Price and Myers, Oxford

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aa

Two new university buildings were built on a former hospital site to the north of Somerville College Campus in Oxford. This new housing for the College’s students and teachers extends along a strip just 6 metres wide by 175 metres long on the site’s northern edge and is designed to link the future Radcliffe Observatory Quarter with the campus. Its architects designed two structures with a new northern access to the campus between them. Striking stair towers, which also mark the entrances, function as points of reference. The salient feature is their windows, several storeys high with deep oak glazing bars, which create a vertical emphasis in the otherwise horizontal structure. Strictly grouped wooden bay windows, framed by areas of exposed masonry, shape the long facades. The bay windows make individual rooms legible from the outside as well as catch some morning and evening sun, despite the rooms’ northern orientation. The whole building was designed to be highly prefabricated. The bay windows were developed using mock-ups. Parts of the load-bearing structure and the complete bathroom pods were prefabricated, as were the stairs and stair towers’ load-bearing wall elements, which are made of prefabricated concrete sections with an exposed brick inner shell that was attached in the factory.

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College garden courtyard Entrance Rubbish room Room Laundry Cleaner’s room Barrier-free room Storeroom Kitchen

Student accommodation

Vertical section • Horizontal section 10

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Scale 1:20

Facing shell, exposed masonry 215/102.5/65 mm Rear ventilation 50 mm, heat insulation 50 mm Rear-ventilated casing, oak, glazed 22 mm Metal sheet cover, powder-coated Plywood panel 18 mm, battens, (sloping) Thermal insulation / beam 100 mm Plywood panel 12 mm, thermal insulation 30 mm, PE foil, fabric-reinforced Plywood cladding, veneered 18 mm Plasterboard, painted Removable cover, veneered plywood Reveal /casing, solid oak, glazed Insulating glazing (fixed) in wooden frames, oak Writing desk, veneered plywood, inside edge band, oak

19

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Rear-ventilated casing, oak, glazed 20 mm Battens 50/50 mm Counter battens 38/38 mm, house wrap Thermal insulation, rigid foam, 60 mm /cross battens Thermal insulation, rigid foam 100 mm /timber frame structure, vapour barrier Veneered plywood cladding 18 mm Carpet, underlay, heating screed 85 mm Impact sound insulation 5 mm, rigid foam thermal insulation 25 mm, steel-reinforced concrete 150 mm Thermal insulation, foil-laminated 55 mm Battens 25 mm Rear-ventilated casing, oak, glazed 20 mm Ventilation flap, solid oak, glazed Interior sliding shutter, veneered plywood with handle edge, oak Prefabricated concrete element 165 mm, with exposed masonry exterior shell 50 mm (attached in the factory)

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221

Example 02

Terrace houses Munich, D 2011 Architects: Bucher-Beholz Architekten, Gaienhofen Assistants: Isabelle Honeck, Marc Jöhle Structural engineer: Helmut Fischer, Bad Endorf

This terrace in the Munich district of Riem was designed to form a stringent yet flexible continuous row of housing. The architects created vertically structured residential units with a spacious, transparent character on the 10.50 ≈ 5.00-metre site. Terraces cut out of the top storey lend rhythm to the rows and admit additional daylight into all the storeys through a central staircase. Light-grey natural slate cladding alternating with large areas of glazing underscores its relaxed effect. The homes are highly insulated, equipped with triple glazing and controlled ventilation with heat recovery, which allows them to achieve a calculated heating energy usage of around 15 – 20 kWh/m2a. In their construction methods too, these houses are unusual, made of a mixed construction of party walls in the form of 15 cm-thick wooden bulkheads with a steel skeleton structure between them. The loadbearing top slab is 75 and 50 mm thick, so it makes flexible changes possible, enabling users to create lofty room heights and light spaces. Slender supports (steel tube pillars | 70/70/4 mm, IPE 140 beams) carry the open and flexible spatial concept, while the building’s skeleton structure made it possible to dispense with dividing interior walls. Fixed floor-to-ceiling glazing makes up a classic mullion-transom system, complemented by oak-framed opening sashes.

222

Terrace houses

1

Sectional view Scale 1:200 Site plan Scale 1:2,000 Vertical section Scale 1:20

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Extensive planting, 100 mm, sealing Thermal insulation 300 mm, vapour barrier Three-layer wooden slab 75 mm Window, oak, insulating triple-glazed inset window Wooden planks 70/40 mm Substructure 60 mm Rubber granulate mat 10 mm, sealing Vacuum insulation panel 30 mm, vapour barrier Three-layer wooden slab 50 mm Slates Wooden battens 50/30 mm, counter battens 20 mm House wrap Thermal insulation 220 mm, vapour barrier Gypsum fibreboard 15 mm Steel profile IPE 140/70 mm Pillar, steel tubing | 70/70/4 mm Floor covering 10 mm Heating screed 60 mm, separating layer, insulation 80 mm Three-layer wooden slab 50 mm Safety barrier, glass

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223

Example 03

Hotel in the Altes Hospiz St. Gotthard Pass, CH 2010 Architects: Miller & Maranta, Basel Quintus Miller, Paola Maranta, Jean-Luc von Aarburg Assistants: Nils-Holger Haury (Project manager), Mirjam Imgrüth, Sabine Pöschk Structural engineer: Conzett Bronzini Gartmann, Chur

Since the 13th century, travellers, pilgrims and traders have found shelter in the Altes Hospiz hostel at the St. Gotthard Pass, situated at an altitude of over 2,000 metres. Repeatedly destroyed by war, fire and avalanches, the originally heterogeneous building has now been extended with an additional storey under a new lead roof with several dormers cut into it to light the renovated hotel rooms. The architects kept the facades and chapel adjoining it to the north in their original forms, removing only a recent addition, while almost completely renewing the Hospiz’s interior structure. Solid interior walls and ceilings were built on the lower two storeys. A timber frame structure above them inside the old quarried stone facade provides adequate insulation and supports the new timber raftered ceiling and roof structure. Between the wooden studs are horizontal planks – a traditional form of construction in the Uri Canton. A concrete band set on the first floor masonry secures the coping and absorbs the thrust from the new roof structure. Areas of new and old plastering merge seamlessly in the facade, while the new casement windows in the added storeys cite the restored elements below.

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Hotel in the Altes Hospiz

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Site plan Scale 1:3,000 Sectional view • Floor plan Scale 1:400 Vertical section • Horizontal section Scale 1:20

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Entrance Plant room Storeroom Cloakroom Sacristy Chapel Guest rooms

8

Lead sheeting 2.5 mm Sealing Timber frame 30 mm Battens 40/55 mm Sealing Timber frame 30 mm Thermal insulation, wood wool 320 mm Vapour barrier Battens 40/55 mm Framework, spruce 30 mm Spruce planks 25 mm Thermal insulation, wood fibre 2≈ 30 mm Cement slab 50 mm Impact sound insulation fleece 5 mm Solid spruce timber floor 100 mm Solid spruce beam 240/360 mm Insulating glazing Ug = 1.1 W/m2K Spruce timber frame, painted, with extruded aluminium profile

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225

Example 03

Vertical section • Horizontal section, casement window Scale 1:20 1 2

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4

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Spruce planks 25 mm Thermal insulation, wood fibre 2≈ 30 mm Cement slab 50 mm Impact sound insulation fleece 5 mm Solid spruce floor 100 mm Solid wood beam Spruce 240/360 mm Cement mortar, rough-trowelled 20 mm Steel-reinforced concrete 300 mm Thermal insulation XPS 160 mm

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Head space 240 mm OSB board 15 mm Mineral wool thermal insulation 80 mm, interspersed with battens 80/60 mm Spruce planks 210/40 mm Spruce framework 15 mm Thermal insulation 100 mm Cement bonded particle board 25 mm Insulating glazing Ug = 1.2 W/m2K in spruce frames, painted Single glazing, float glass 4 mm Vermiculite fill 50 mm Masonry (pre-existing) 500 mm

Example 04

Detached house

Detached house a

Krailing, D 2013

4

Architects: Unterlandstättner Architekten, Munich Thomas Unterlandstättner Assistants: Telemach Rieff, Anke Göckelmann, Enrico Schreck Structural engineers: a.k.a Ingenieure, Munich

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Floor plan, ground floor Scale 1:200

On a quiet 1960s housing estate to the southwest of Munich, the architects created a home for a family of five. The building features precisely arranged openings of various sizes that articulate the relationship between inside and out in very different ways, resulting in four very different facades. Three recessed bays lend the house, with its anthracite-coloured plaster, a sculptural quality. A long set-off shields the entrance and area in front of the kitchen, which is separated by a concrete wall. A recessed southwestern corner creates a covered outdoor seating area and opens up the living room to the garden. A sloping floor continuing through to the outside orients the dining area towards the sunken terrace, while a row of windows flush with the ground screens occupants from the neighbouring property. On the upper floor, the facade facing south-east is closed, with skylights illuminating the bathrooms behind it. On the gable ends, tripartite windows, each consisting of an area of fixed glazing, an opening sash and a steeply angled oak reveal, contrast with the dark, emphatically rough plaster over the thermal insulation system. The three recessed bays, with their finer smooth white plaster and oak surfaces, hint at the house’s carefully detailed interior structure

Vertical section • Horizontal section

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Entrance Cloakroom Living room Terrace Eating area Utility room Kitchen

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Zinc-plated gutter, angled, heatable Ring beam, steel-reinforced concrete Mounting for sunshade casing, stainless steel profile Strips of resol rigid foam thermal insulation strips 25 mm Triple glazing, toughened safety glass 4 mm + space between the panes 16 mm + float glass 4 mm + space between the panes 16 mm + toughened safety glass 4 mm in oak frames UW = 1.0 W/m2K Organic sgraffito plaster, anthracite 40 mm Natural stone slabs of Wachenzell dolomite, open-pored 20 mm, layer of mortar 10 mm Cement screed 58 mm In-floor heating in dimpled sheeting 22 mm Impact sound insulation 30 mm Installation layer / thermal insulation 30 mm Steel-reinforced concrete 200 mm, plaster 15 mm Triple-layered oak, veneered 20 mm an Airspace 160 – 0 mm, house wrap Mineral wool thermal insulation 80 mm Masonry 90 mm, plaster 15 mm

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227

Example 05

School Guildford, GB 2009 Architects: DSDHA, London Assistants: Deborah Saunt, David Hills, Martin Pearson, Claire McDonald, William Haggard Structural engineer: Adams Kara Taylor (AKT), London

This school campus in Guildford is an educational institution that is also open to the public. Outsiders can use its theatre, sports hall and chapel, making the compact complex part of the borough’s identity. An effective layout guides users through the centre of the campus, opening and integrating the school into its environment – a concept that has made it a model British school. The building also set new technical benchmarks as the first public building in England to use decentralised ventilation and combined heat recovery. Air vents are irregularly distributed across the brick facade under classroom windows in expanded butt joints that otherwise measure 15 mm, while the horizontal joints are 8 mm wide. All joints between the bricks are 5 mm deep, lending the facade a subtle profiling. This look is underscored by windows set deep into the walls, some of them floor-to-ceiling, with slanted reveals, providing views of the landscape and Guildford Cathedral. Inside, a wood-panelled, multistorey hall forms the school’s communicative centre. The stairs, hallways and classrooms were built using concrete poured on site and concrete blocks, creating a restrained environment that is also protected from vandalism.

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Heat recovery in winter

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Ventilation slot under window sheet, aluminium Grid cover, stainless steel Brickwork shell Stainless steel exhaust air duct 50/35 mm with lugs welded on, mortared into masonry joints Air distribution Steel reinforced concrete with 700/280 mm gaps for ventilation ducts Floor structure: Carpet or PVC Cement screed 90 mm Separating layer Steel-reinforced concrete slab 325 mm Ventilation slot, interior 18 mm MDF casing for ventilator with 33 mm soundproofing

Ventilation in summer

9 10 11 12 13 14 15

on a tubular steel substructure Exhaust ventilation, interior Cross plate heat exchanger Filler piece, aluminium sheeting 2 mm Extruded PVC U-profile with PU rigid foam insulation core MDF cover 18 mm, laminated Opening sash, solar protection glazing in aluminium window frame profile Wall structure: Masonry Cottbus clinker brick 290/90/50 mm, Pigmented mortar joints Mounting anchor, stainless steel Rear ventilation 50 mm Thermal insulation, phenolic foam 60 mm Steel-reinforced concrete pillar 200/800 mm

School

Sectional view Scale 1:1,000 Functional principle of the ventilation / heat recovery Horizontal section, window glazing • Vertical section, opening sash Scale 1:10

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Example 06

Renovation of the Bauhaus Dessau Dessau, D 2011 Architects: Winfried Brenne Architekten, Berlin Energy planning: Transsolar, Stuttgart

Built in 1925 –1926 and designed by Walter Gropius, the Bauhaus building is on UNESCO’s World Heritage list and the embodiment of Modern architecture. Founded in 1919 as the “Staatliches Bauhaus in Weimar”, the then Hochschule für Kunst und Gestaltung (art and design college) moved to Dessau in 1925. The complex consists of three L-shaped buildings arranged like the sails on a windmill. Its northern wing is home to the city’s vocational college, while the four-storey studio building with its projecting balconies houses studio flats for students and “junior masters” (Jungmeister). The third element is a three-storey workshop wing that features an enveloping glass curtain facade. A single-storey connecting building containing spaces for public events, an auditorium and canteen connects the workshop wing and studio building, while a two-storey elevated bridge links the workshops with the school. The Bauhaus building was seriously damaged during the Second World War and provisionally repaired after 1945. A reconstruction in 1976 largely restored its original appearance. In 1994, the Bauhaus Dessau Foundation was set up, and in 1996, the complex was placed on the UNESCO World Heritage list. In a complete renovation carried out from 1996 to 2006, the buildings were thoroughly refurbished and their historic appearance restored. The Bauhaus building is largely open to the public and used as a venue for events and exhibitions conveying the Bauhaus ideas and ideals. The cost of operating the building grew steadily over the years due to its exterior wall structure, a brick-clad ferro-concrete framework with large, steel-framed single-pane windows. Its many leaks and draughts, resulting in a space that was difficult to heat in winter and suffered from high temperatures in summer, led its administrators to consider renovating it to optimise its energy use. During the renovations, the air conditioning and heating technology was optimised, and in some areas (the northern and western facades of the northern wing and eastern facade of the studio building), windows not originally installed when the building was built were replaced with steelframed windows with thermally separate frame

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1st floor

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Renovation of the Bauhaus Dessau

Sectional view • Floor plan Scale 1:1,000 Vertical section • Horizontal section Scale 1:10 5 6 7

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Studio apartment Administration, seminar rooms Former Director’s office Presentation / Workshop Steel sheeting cover, galvanised 1.5 mm Top/bottom window edge Steel profile ∑ 130/50/10 mm (original) Thermally separate 3 and 4-mm hot-rolled steel window frame profiles, alkyd resin coating incl. corrosion protection, white inside, grey outside, screwed onto a substructure, insulation, 12 mm, in the interstices Outward-opening, top-hung sash, 5 mm insulating

9 10 11 12 13 14 15 16 17

float glass + krypton gas in the space between the panes 10 mm + 4 mm float glass Tilting sash Steel pillar profile Å 75 mm (original) Window joint, thermally separate steel angle profile Fixed glazing Window profile with sash frames Steel profile, thermally separate middle seal Sash bar, thermally separate steel profile Brass window handle Window edge, steel profile 75/45/6 mm (original), thermally separate Windowsill, terrazzo 35 mm

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Example 06

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profiles and double insulating glazing. Replacing these windows was only possible on the proviso that the building’s historic appearance could be reconstructed inside and out, especially the subtlety of its window frames and sash frames and the fittings that were installed when the building was built. A product already on the market was modified in the course of an intensive planning and development process to produce frame profiles with the advantage of flexible formation. They are made of hot-rolled flat steel profiles, laserwelded U-profiles and a thermally separating glass fibre-reinforced plastic bridge. These novel frames made it possible to restore the building’s desired architectural heritage and design quality, while retaining its historic hardware, such as the visible Crémone bolt latches and top-hung window fittings.

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Renovation of the Bauhaus Dessau

Horizontal section • Vertical section Studio building facade Scale 1:10

Mullion detail, studios Scale 1:5

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Original building 1926

Reconstruction 1976

Renovation to optimise energy use 2011–14

20 mm lime insulating plaster with lightweight silicate-based aggregate Edge profile: Flat steel ¡ 4 mm Thermal insulation Flat steel ¡ 4 mm Pivoting sash: 5 mm insulating float glass, + space between the panes, krypton gas, 10 mm + 4 mm float glass Flat steel frames ¡ 3 mm, hot-rolled, thermally separate

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Alkyd resin coating incl. corrosion protection, white inside, grey outside Steel profile with sash frame and middle seal Brass window handle with cremone bolt latch Fixed glazing Balcony door Top section, top-hung outward opening sash Opening rod Tilting sash Windowsill, terrazzo 40 mm Parapet area, door: Thermal insulation fill 40 mm 2≈ 3 mm steel sheeting Floor: Stone-wood screed 35 mm Steel-stone slab (original)

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Example 07

Home and workshop Berlin, D 2011 Architects: Augustin und Frank Architekten, Berlin Assistant: Julia Lorenz Structural engineer: Pichler Ingenieure, Berlin a

a

This two-storey building, whose original use has not been definitively identified, was built in 1910, although its construction file only goes back to 1932. What is certain is that it has undergone very different phases throughout its life. Documented uses reveal that it was a car and metalworking workshop in the 1930s, later a market hall, and then public administration offices in the 1970s. It was this last usage that gave the building its floor plan consisting of a central corridor with offices along both sides. At that time, its damaged original roof was replaced with a plank truss structure and a suspended ceiling was installed. During its most recent

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conversion, which mainly involved the interior and facade, all of its dividing walls and suspended ceilings were removed and both storeys turned into ample, loft-style spaces. The ground floor’s historic screed was replaced by a heating screed with an insulating and sealing layer. Once the Prussian capped vault was filled, a classic wooden floor could be laid on the upper floor’s steel beams. One striking feature of the new mixed-use working and living space is the large polycarbonate panel sliding element in its south-eastern gable facade. When open, it extends the space outside to the courtyard, lending it the quality

of a terrace. One of the advantages of the translucent material is its low weight compared to glass, which allows for a relatively delicate substructure. The polycarbonate panelling’s multilayered structure also has good thermal characteristics, which allow it to achieve very low U-values. Wooden bulkheads serve to tightly close the connecting joints in winter. Existing wood-framed casement windows in the eastern and western facades were largely retained. New, outward-opening double windows flush with the exterior walls supplement the existing mullioned windows, while new, domed skylights in the roof provide extra daylight.

Home and workshop

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Sliding door, 10-chamber polycarbonate panel 50 mm, circumferential aluminium system profile 50 mm Tubular steel frame profile | galvanised 60/60/5 mm Wooden frame made of squared timber 80/80 mm Wall projection, multiplex board, birch 30 mm, sliding Aluminium sheet metal cover, angled 2 mm Sliding door guide rail, tubular steel | 35/35/3mm Lintel, masonry gable, steel profile 2≈ IPE 220 Roller profile: steel sliding door roller 150 mm Slide rail, tubular steel Ø 30 mm, attached with flat steel lugs to a galvanised rectangular steel pipe Floor edge, removable planks 40 mm Floor covering, Solid wood floorboards 40 mm Plywood substructure 30 mm Levelling battens, 50 mm In-floor heating Safety rail, handrail, tubular steel Ø 38 mm Steel cable parapet Ø 3 mm

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Example 08

Exhibition pavilion

Exhibition pavilion Trondheim, N 2011 Architects: TreStykker 2011 (workshop), Trondheim Team: Trygve Ohren, Eivind Kristoffer Fasting, Ragnhild Pedersen Foss, Tomas Aasved Hjort

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Exhibition space Circumferential corridor Cloakroom and kitchenette Roofing paper, particle board 20 mm, mineral wool thermal insulation 100 mm 3≈ interior door, recycled 150 mm Beams, total height 600 mm: recycled plywood 2≈ 10 mm, oak planks between them Window element, recycled Fittings from second-hand interior doors Plywood panel 2≈ 10 mm, painted white with thermal insulation in between 60 mm Floor structure: Solid wood blocks, untreated resinous pine 100 cm Expanded polystyrene thermal insulation 50 mm Gravel

RAKE, an art and architecture exhibition pavilion on a busy main street in Trondheim, is the result of a workshop initiated by four students with the goal of creating a shared space for a mutual exchange of ideas and information for the three Norwegian architecture colleges in Trondheim, Oslo and Bergen. Thirty students were responsible for designing and building the 45 m2 building, working with advice and support from an architect and an artist. With just a few exceptions, only recycled building materials and products were used, almost all them from an office building that was about to be demolished. The striking facade consists of two layers of old windows. Its outer layer was assembled from many different formats, similar to a puzzle, with white-painted wooden panels filling the areas between them. Only windows of the same size were used for the inner layer, and they echo the 60 cm grid of the open-plan timber support structure. As is often the case in northern Europe, four of the windows can be opened outwards for ventilation and close automatically in a strong wind. Inside, three lightweight dividing walls and a circumferential corridor form presentation spaces. In front of the entry area, with its 1970s wooden door with a wired-glass pane, visitors can sit, screened from the street, on wooden blocks.

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Example 09

Shop renovation

Shop renovation Bamberg, D 2007

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Architects: Nickel und Wachter Architekten, Bamberg Frank Nickel, Jochen Wachter

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Entrance Courtyard of the house at the rear Salesroom Plastered masonry 410 mm (pre-existing) Wood-framed French window Porch: Frame steel sheeting 5 mm, Thick enamel coating, Top inner side, aluminium sheeting, angled, powdercoated 5 mm, underside, wooden slats, 30/10 mm Kambala (African mulberry) Trace heating Built-in light IP 65 Gas pressure damper Steel sheeting embrasure housing 3 mm, thick enamel coating, gearbox incl. hand crank on the side Exchangeable covering, summer: solid Kambala wood 15 mm, winter: grating 15 mm, screwed onto a steel bracket Sprocket with steel shaft, mounted on ball bearings Exchangeable steps, summer: solid Kambala wood 15 mm, winter: grating 15 mm, screwed onto a steel bracket Steel-reinforced concrete platform

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Example 10

House and jeweller’s studio Wißgoldingen, D 2008 Architects: Kaestle Ocker Roeder Architekten, Stuttgart Structural engineers: Ingenieurbüro Hottmann, Schwäbisch Gmünd

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To build an intensive relationship with the landscape was the client’s express wish, and this house, clad with square white tiles, fulfils that wish. Situated on a south-western slope of the Swabian Jura, the two-storey building, consisting of two superimposed U-shaped structures, is clearly oriented towards the south, opening up views of the surrounding hills. Its upper cube is oriented towards the street, where the entrance and the jewellery designer’s studio and workshop are located. Stairs lead down to the garden level, which houses bedrooms and other rooms and a living and dining area with ad-

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joining kitchen. A large glass facade opens up the kitchen to the landscape. Its 3.80-metre floor-to-ceiling glazed elements with their delicate profiles were the first of their kind when they were built. The sliding doors have two, three and four tracks, allowing some sections to be opened up to three quarters of the door’s total area. One particular challenge lay in creating a corner opening without upright jambs. Where two sliding elements overlap, only a slender 20-mm vertical glazing bar is visible. The door’s floor track is flush with the floor, strengthening the impression of the apparent merging of inside and out.

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Levelling fill 45 mm Steel-reinforced concrete slab 320 mm PU thermal insulation 120 mm Plaster trowelled over mesh Smooth plaster Curtain rail Sliding window, frameless, four-track: insulating double glazing Laminated safety glass 8 mm + 16 mm space between the panes + 8 mm laminated safety glass Aluminium /stainless steel frame Heating and cooling ceiling Solid wooden planks, Canadian Yellow Birch 22 mm, OSB 25 mm Flooring sleeper / thermal insulation 80 mm, Flooring sleeper /cavity fill 80 mm, Sealing Steel-reinforced concrete 220 mm Facade drain White concrete prefabricated element 40 mm

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Example 11

District police department Mettmann, D 2005 Architects: Enno Schneider Architekten, Berlin Assistants: Thomas Sugge, Thomas Rabbe, Markus Ulmann, Stephan Meyer, Michael Manzke, Christoph Mund, Jochen Herrmann, Senta Wiemann, Stefan Lücke Structural engineers: IFB Frohloff Staffa Kühl Ecker, Berlin Energy planning: Zibell, Willner & Partner, Berlin

Situated at the western entrance to the town, Mettmann’s new police department building is a striking new feature in the town’s urban fabric. The building is part of an overall concept incorporating three separate buildings housing different departments arranged around a square. Its individual storeys are clearly identifiable on the organically shaped building’s shimmering grey-green envelope. A recessed, continuously glazed ground floor forms the building’s plinth. It is open to the public and houses the police station, central atrium and visitor area. Offices, including the control centre and command post, are in the four upper storeys behind a special

1st floor

interpretation of a perforated facade consisting of opaque and transparent areas. The interplay of alternating transparent and closed facade elements is the result of the demands of individual uses. The element facade consists of large areas of floor-to-ceiling fixed glazing, insulated aluminium panels and openable ventilation flaps, clearly separating the functions of lighting and ventilation. On its southern side, the building is also equipped with solar protection glazing. Bored pile foundations and a high groundwater table level made it easier to implement a sustainable energy concept using geothermal energy.

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Gravel 80 mm, sealing Thermal insulation 250 mm, vapour barrier Steel-reinforced slab with structural component activation 320 mm 8 mm fixed laminated safety glass glazing + 18 mm space between the panes + 6 mm toughened safety glass, aluminium profile frame Aluminium sheeting, angled 3 mm Thermal insulation 50 mm, sealing Thermal insulation 80 mm Glass joint with silicone seam Vertical blind to protect from glare Needle felt carpet, compound screed 80 mm, Steel bracket, ∑ 200/100/8 Steel-reinforced slab with structural component activation 270 mm Media duct 60 mm Fire protection panel 25 mm, attached to a steelreinforced concrete slab with a steel bracket Ventilation element, lowering / folding mechanism: aluminium sheeting 3 mm, air space, Thermal insulation 120 mm, aluminium sheeting 3 mm

District police department (Kreispolizeibehörde)

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Example 12

Training centre Sungai Penuh, RI 2011 5

Architects and structural engineers: TYIN tegnestue Architects, Trondheim Yashar Hanstad, Andreas G. Gjertsen Assistants: Therese Jonassen, Morten Staubo, Gjermund Wibe, Kasama Yamtree Student assistants: Bronwyn Long, Sarah Louati, Zofia Pietrowska, Rozita Rahman, Zifeng Wie

In the new training centre of a fair trade cinnamon growing and marketing cooperative on the banks of Kerinci Lake in eastern Sumatra, farmers and agricultural workers can find out more about the fundamentals of sustainable management and the global cinnamon trade. The goal of the Norwegian architects and students who planned and built this model project was also to make use of local artisans, construction techniques and building materials. They estimated a budget of around € 30,000 and a period of three months for the design and subsequent construction on the 500-m2 site. That both

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targets were met is due to the employment of over 60 workers and to the building’s design, which is based on separate buildings arranged around an inner courtyard and strictly separated structural elements. It meant that the builders could start work on the wooden roof structure above the steelreinforced concrete floor slab long before the plastered walls were completed. This construction method also made it possible to provide natural ventilation and cooling for the interior and separate the structure into materials with different oscillation frequencies, which has contributed significantly to

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helping the training centre survive some major earthquakes undamaged. While the bricks came from regional companies, the timber used in the roof support structure, window frames and doors was sourced entirely from the cooperative’s directly adjoining cinnamon forests. Large branches, which have to be cut off to harvest the cinnamon bark anyway, were cut into planks on the building site. This method ensured short transport routes, relatively low material costs and close links with Sumatra’s surrounding cultural landscape and building traditions.

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Example 13

Extension to the Landesdenkmalamt (State office for monument preservation) Esslingen, D 2003 Architect: Odilo Reutter, Stuttgart Structural engineer: Heinz Meissnest, Esslingen am Neckar Daylight technology: Helmut Köster, Frankfurt am Main

The new headquarters of the Baden-Württemberg Landesamt für Denkmalpflege unites the authority’s branch offices, previously scattered across the state, under one roof. To meet the high climatic and technical demands of the planned laboratory, workshop and office spaces, the new headquarters, established in a 19th century grammar school, were renovated and extended. A glazed tower and a single-storey workshop building with an expanded metal envelope supplement the late-19th century complex. All of the buildings are connected with each other at the basement level. A long lighting groove following the course of the town’s medieval moat supplies the basement workshop with daylight. The office tower, which docks onto the old building via gangways, is completely glazed. Its glass facade, with specially designed fixed light reflecting louvres in the spaces between its panes, has several functions: thermal envelope, protection from the sun and light control. In summer, the louvres effectively deflect the rays from the high summer sun outwards. In winter, they reflect the rays of the lower sun deep into the rooms and onto the unclad solid ceilings, warming them by up to 3 kelvin. Together with the heating and cooling pipes installed deep in the slabs, this ensures that the workrooms have an even basic temperature. Flat, thermally activated prefabricated concrete elements around the edges of the ceilings, which can flexibly react and adjust to temperature fluctuations in the facade, supplement this inert system. This makes additional air conditioning technology superfluous and keeps the interiors free of technical installations. The building’s load-bearing structure, which is limited to a bracing wall on each floor and a core, gives users plenty of scope to configure individual floor plans. Parallel vent windows without louvres regularly distributed across the facade provide every user with individual ventilation options and wide-ranging views.

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Summer: Rays from the high summer sun are deflected outwards. The curved interior light deflection element reflects indirect daylight into the interior. Winter: Light from the lower winter sun enters directly. Light deflecting elements in the upper area of the windows reflect daylight deep into rooms, into the lower areas of windows and onto ceilings without glare. The louvres are thin, so they do not impede views.

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Aluminium louvres in front of an expansion joint Blind with light-deflecting louvres Parallel ventilator windows with thermal insulation glazing, 8 mm toughened safety glass + 16 mm space between the panes + 10 mm laminated safety glass, Ug = 1.1 W/m2K Mastic asphalt screed 30 mm PU surface coating Lightweight concrete levelling fill 95 mm PE foil separating layer Extruded rigid foam thermal insulation panel 220 mm Steel-reinforced concrete 200 mm, painted on the underside Aluminium cover plate 3 mm Aluminium profile fi 20/20/2 mm

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Example 14

Islamic cemetery Altach, A 2011 Architect: Bernardo Bader, Dornbirn Assistant: Sven Matt Site consulting artist: Azra Akšamija, Boston Structural engineer: merz kley partner, Dornbirn

After an intensive inquiry into Islam and its funeral rites, the architects developed an open, clearly designed overall plan without obvious symbolism for the Islamic Cemetery in Vorarlberg. Taking as their starting point Muslim and Christian notions of the cemetery as the prototypical garden, which is created by first demarcating a clearly defined area of land, the planners set concrete wall panels of varying heights in the meadow-like landscape. The panels enclose the gravesites in separate but uniform spaces that are oriented towards Mecca. Designs for all the complex’s roofed spaces also developed out of the fundamental idea of “the wall”. On the long facade

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next to the entrance, visitors are greeted by an ornamental openwork wooden wall element (Mashrabiyya) with a hexagonal pattern whose lively interplay of light and shadow also features in the assembly room. Lights with thick glass covers set into ring-shaped ceiling recesses provide an additional light source. In the prayer room (Mescid), a window facing Mecca functions as a prayer niche (Mihrab). Three slightly offset metal mesh curtains with gold-plated wooden shingles woven into them hang on the whitewashed wooden wall showing the words “Allah” and “Mohammed” in Arabic script. The complex’s black and red pigment-dyed

jointless concrete presents a smooth and monolithic image. Holes for the formwork anchors were subsequently unobtrusively closed over. The concrete’s exterior surface has a structured relief texture that was created using formwork made of rough-sawn planks in three different thicknesses. In contrast, the inner surfaces are smooth, subtly differentiating the interior and exterior spaces. Small cracks in the jointless building are part of the plan, while the type and positioning of reinforcement will prevent larger cracks from forming. The walls were first concreted to their full height, then the ceilings, and finally the interior’s floors.

Islamic cemetery

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Gravel 160 –190 mm, sealing Steel-reinforced concrete 325 – 300 mm Mashrabiyya: CNC-milled oak, plug connectors and wooden dowel connections ¡ 60/200 mm Oak cladding 20 mm Steel profile pillar ¡ 80/120 mm Gaps in the steel-reinforced concrete for attaching the Mashrabiyya Steel-reinforced concrete 300 mm, dyed with red and black iron-oxide pigments, relief structure on the outside, smooth on the inside Built-in lights in recesses, Ø 1,000/70 mm Cover, glass plate Ø 190 mm Steel-reinforced concrete, smoothed 250 mm Granular sub-base 50 mm Gravel 300 mm

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Example 15

Detached house Villarcayo, E 2012 Architects: Pereda Pérez Arquitectos, Pamplona Carlos Pereda Iglesias, Óscar Pérez Silanes Assistant: Teresa Gridilla Saavedra Structural engineer: José Loaquín Arricibita, Pamplona

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Four main parameters governed the design for this house for a young family in Villarcayo in the Castilian province of Burgos: a limited budget, a desire for a simple, contemporary architectural language, the decision to build a single-storey house as close as possible to the garden, and its location in the flood plain of the Rio Nela, a tributary of the Ebro. The result is a clear-cut concrete and timber building that is fairly safe from floods, poised just half a metre above the ground. The hierarchical principle of gradual opening, from absolute privacy through shared family life up to the more public verandas and garden areas, can be clearly seen in every room in the house’s H-shaped floor plan. Along its north-south axis and two different garden areas, the house is entirely permeable, while to the east and west, it is completely closed off to the surrounding neighbourhood. Its two side wings, with their exposed concrete and timber-clad rear walls on the garden side, house various private rooms. Their size was minimised to make more space for an almost square central living space, which is the house’s transparent spatial and social heart. All the private rooms can be reached from here. To the north and south, the high-traffic living area opens up completely to the garden through a glass facade. Floor-to-ceiling, frameless glass elements retreat well into the background behind the continuous roof edge, creating two protected verandas. Timber-clad sliding elements can be closed flush with the facade or opened at the sides. Although dominant concrete roof and floor slabs clearly demarcate the boundary between inside and out, the very sparsely furnished living area has unifying qualities. It brings the garden into the house and conversely extends the living space into the outdoors, creating a hybrid space that can also be completely closed as required.

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Example 16

Illwerke Centre, Montafon Vandans, A 2013 Architects: Hermann Kaufmann, Schwarzach Assistants: Christoph Dünser, Stefan Hiebeler, Thomas Fußenegger, Michael Laubender, Guillaume Weiss, Ann-Katrin Popp, Benjamin Baumgartl Structural engineer: merz kley partner, Dornbirn

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In the Vorarlberg valley of Montafon, on the banks of the reservoir lake in Vandans, the architects created a new central office building for the Austrian energy company Illwerke. The new, 120 metre-long, five-storey modular timber hybrid building design houses 270 workstations, most of them open-space. The hybrid timber and concrete load-bearing system’s double beams and supports, specially developed for this building, and a composite ribbed roof shape the space and guarantee compliance with strict fire safety regulations. The window elements consist of a large area of fixed glazing that is flush with the facade and a mobile opening sash set deeper into it. From the inside, the fixed glazing’s wooden frames are not visible. The windows provide unobstructed views of the picturesque surrounding landscape from all workstations. Each prefabricated facade element consists of three pairs of supports and three parapet elements, all offset. Window elements were delivered separately to the building site and installed between the beams. Roof slabs, projecting over the bands of windows, protect workstations from glare, provide the timber with structural protection and prevent fire from spreading into the next storey. They were prefabricated in modules and bolted on site onto steel consoles that were added to the parapet elements in the factory. The building envelope meets passive-house standard criteria. Panels between the ceiling beams provide heating and cooling and function as sound absorbers.

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Example 17

Residence Tokyo, J 2011 Architects: Sou Fujimoto Architects, Tokyo Structural engineer: Jun Sato Structural Engineers, Tokyo

With its feeling of boundless openness, this wall-less structure with its airy, distributed levels is a major challenge in many senses for its inhabitants. The contrast between the simplicity of its structural and design means and the complexity of its spatial fabric opens up a confounding wealth of possibilities. Steps between the panels can be used as seats or tables, as spatial dividers or simply as sunscreens. They contain possibilities for permanent change and transformation. The spatial flexibility offers levels of privacy to the modern urban nomad existence, governed as it is by mobility. Its position in the middle

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of a residential area in central Tokyo makes the “House NA” at once an imaginary tree house, experiment and a provocation. It offers unlimited free space while demanding a permanent ability to decide, to meaningfully fill emptiness and to give a direction to a finely balanced openness. This maximally “transparent” kind of housing, visibly accessible to the point of transparency, combines openings of all kinds and sizes, all of them made of glass. There are areas of fixed glazing and glass windows and doors with pivoting, tilting, folding and sliding mechanisms and others that only open outwards.

The architect explains that “This white steel structure does not at all look like a tree, but the life led and experienced in this house is a contemporary adaption to the richness of the lives our ancestors led when they still lived in trees. The house represents a relationship between the city, architecture, furniture and the body, between the natural and unnatural. Dividing its storeys into individual floor areas the same size as the furniture means that this house provides dwellings that harmonise with each other through a spatial and chronological relativity – like a tree.”

Residence

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Example 18

Office building Lustenau, A 2013 Architects: Baumschlager Eberle, Lustenau Project manager: Jürgen Stoppel Assistant: Hugo Herrera Pianno Structural engineer: Mader & Flatz Ziviltechniker, Bregenz Energy planning: Lars Junghans, Michigan

This six-storey building, its architects’ new company headquarters, is in the commercial district of Lustenau, close to the Swiss border. It is also home to other building industry tenants, a gallery and a cafeteria. The planners wanted to create a comfortable, lowmaintenance building that would make minimal use of energy and technology. “2226”, the building’s name, stands for the temperature range of 22 to 26 °C, which most people find pleasant. Its construction, spatial organisation and a complex control system enable the building to operate without heating, cooling and ventilation equipment. Newly developed control software manages energy flows. The close coordination between the energy planning and architecture becomes clear at the interface between inside and out. The building’s interiors are 3.36 to 4.50 metres high and feature electronically controlled ventilation louvres and fixed floor-to-ceiling vertical glazing. The openings’ dimensional ratio of about 5:3 ensures optimum lighting, even at a depth of 12 metres in the standard storeys. The window formats seem to stretch the 24 ≈ 24 ≈ 24-metre building, allowing it to be perceived more as a tower. Its cubic form and harmonious proportions were deliberately chosen to optimise energy use because they offer the best ratio of surface to volume. Its low proportion of window area, just 24 % of the total building envelope, helps minimise heat losses. The solid, white-plastered building envelope is made of two layers of 38 centimetre-thick brick – an inner layer consisting of vertical core bricks with a load-bearing function and an insulating outer layer with a larger proportion of holes. Deep-set windows and the building’s orientation help users adjust the penetration depth of sunlight according to the season and shade the building, even in summer. Heat generated by users and equipment provides enough heating energy in winter. The ventilation louvres open when carbon dioxide levels in the room exceed permissible values, and they also open at night after hot summer days.

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Example 19

Renovation of the former workers’ canteen at the Pulverfabrik Rottweil Rottweil, D 2004 Architect: Bernd Liebmann, Böblingen Client: Holzmanufaktur Rottweil GmbH, Rottweil Hermann Klos, Günther Seitz

Professor Heinrich Henes from Stuttgart had the “Pulverfabrik” ensemble built in 1909. After various conversions and additions between 1915 and 1936, the factory workers used this building as their canteen until 1975. In the 1980s, the building was partly gutted by fire and sat empty for some time until the Holzmanufaktur Rottweil company planned complex renovations for it. Their goal was to restore and rebuild the building so that it could be used as a workshop and offices. The listed historic building complex required special treatment. One of the architectural details requiring particular attention was its

historic windows. The aim during the renovations was to not replace the existing windows with new ones. To retain the original windows and meet current standards, the windows’ energy efficiency characteristics had to be improved. As well as repairing the windows’ timber frames and fittings, their puttied chamfers were renewed and new coloured paint applied. Instead of replacing the historic panes with special thin insulating panes, which was one possible alternative, a decision was made to use secondary windows. These were once common and involve an additional window attached on the outside, making the existing

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window a double one. The secondary windows are equipped with insulating glass and can only be opened outwards. An additional seal was cut into the outer window’s frame rebate to optimise their overall structure and energysaving characteristics. The window sashes can only be moved with the help of latch hooks (a hook attached to two grommets for security), and they can be completely taken off their hinges if necessary. The inner windows’ various opening types were retained, some of them with pivoting sashes and others with turning sashes.

Renovation of the former workers' canteen at the Pulverfabrik Rottweil

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Example 20

Renovation of the Botanical Garden hothouses

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Zurich, CH 2012 Architects: Hubacher + Peier Architekten and Haerle Hubacher Architekten, Zurich Assistants: Matthias Hubacher, Erhart Peier, Christoph Haerle, Sabina Hubacher Structural engineer: Walt + Galmarini, Zurich

The University of Zurich’s Botanical Garden was built in the late 1970s by architects Hubacher, Issler and Maurer and landscape architect Fred Eicher on a 56,600-m2 site. They consist of the Botanical Garden itself, the Institute buildings, service buildings and the hothouses, with their striking domes. After 35 years of operations, the buildings were showing marked signs of ageing. The glazing of the hothouse domes, in particular, had lost much of its translucency due to obscuration and algal growth, which was seriously affecting plant growth. The service buildings were also in need of repair, the buildings’ technology was obsolete, and energy and

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operating costs were high. After a feasibility study, a decision was made to renovate the entire complex in an overall plan in which all works would respect the complex’s delicate appearance. Construction work was carefully carried out in planned stages so as not to completely disrupt operations or endanger valuable plants. To create a new building envelope, the old acrylic glass elements were removed, replaced with a double-shelled envelope made of 6 mm-thick acrylic glass on a new substructure and mounted on the existing renovated and cleaned tubular aluminium support structure. This made it possible to ventilate the space between the

panes, from bottom to top, with special connecting grommets between the elements. Air in the roof is channelled downwards through installation ducts integrated into the vertical support tubes. The double-shelled elements had circumferential acrylic glass spacers adhered to them in the factory to prevent soiling of the interior. Automatic ventilation louvres were installed in the domes’ roof ridge areas to release air heated by sunlight. An electric, manually operated shading system was also attached to the interior to prevent it from overheating.

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Acrylic glass 2≈ 6 mm (new) Acrylic glass spacer with special connecting grommets for ventilation Ø 20 mm (new) Aluminium profile substructure 35/80 mm (new) Support structure (original), aluminium piping Ø 60 – 90 mm, variable diameters in each house Chromium steel cable, prestressed, attached with grommets to nodes Acrylic glass (PMMA) 6 mm (original) Acrylic glass dome, openable

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Example 21

Extension and improvements to the energy efficiency of the ift Rosenheim building

Extension and improvements to the energy efficiency of the ift Rosenheim building Rosenheim, D 2010 Architects: Guggenbichler+Wagenstaller, Rosenheim Project manager: Roman Seiderer Structural engineers: Guggenbichler+Wagenstaller, Rosenheim

A need for 50 new workstations, its staff’s constantly changing tasks, insufficient training rooms and the restructuring of the testing laboratories made a new annex and a redesign of the interior of the ift Rosenheim building necessary. As a testing and research institute for windows, facades, glass, doors, portals and their fittings, the ift felt obliged to use the most modern window and facade technology in carrying out the necessary optimisation of energy consumption of its existing building and new annex. Without changing the facade’s look, the existing building’s energy efficiency was improved by installing a highly insulated exterior envelope and aluminium casement windows, which with their combination of tilting sashes and automatic parallel-hinged sash windows provide draught-free, precisely adjustable and energy-efficient natural ventilation. Their external white glass panes improve sound insulation, even when open, which is an advantage in the conference rooms. Blinds can be used to counteract the effects of weather, and a night ventilation system that also prevents break-ins is in use. In the annex, with its striking red thin-film technology facade, double-glazed coupled windows with outer protective white glass panes were installed. Their mechatronic tilt and turn fittings can be operated manually, by computer, with time switches or sensors or they can be connected to the building’s automation systems.

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Example 22

High-rise building

High-rise building Singapore, SG 2003 Architects: WOHA Architects, Singapore Assistants: Gerry Richardson, Sim Choon Heok, Punpong Wiwatkul, Esther Soh, Lisa Yun, Sabrina Foong Lee Li Leng, Timothy Tan, Susan Tan Structural engineers: Meinhardt, Singapore

No. 1 Moulmein Rise is a slender, 102 metrehigh residential tower containing 50 apartments over 28 floors in Singapore. To vary the facade design and ensure a comfortable interior climate for inhabitants, its planners developed various facade modules, such as the recessed sections and bay windows on its southern facade, which are equipped with “monsoon windows”, an adapted local detail. A horizontal, protected window grating enables occupants to make use of a cool wind to ventilate the apartments, even during heavy tropical rain. The grating prevents objects from falling and can be lifted for the maintenance and cleaning of the parapet’s glass panes.

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Example 23

House Wollerau, CH 2005 Architect: Valerio Olgiati, Flims Project manager: Pascal Flammer Structural engineers: Conzett Bronzini Gartmann, Chur Sinking window system: Roffler Metallbau, Klosters und Malans

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“This building’s focus is the building in itself – not the site”, says the Graubünden architect about this house, for which he was awarded the Schweizer Betonpreis (Swiss concrete prize). Built on a slope near Lake Zurich, visitors enter the freestanding house at an unusual point, the upper storey’s southeastern corner. A curving, almost labyrinthine corridor, lit only by circular skylights, leads the visitor past private rooms and, before they can guess at the house’s form or organisation, down a winding staircase to the ground floor. Here the living area, described by the architect as the house’s "central space", opens out, suffused with light and almost completely filling the building’s square floor

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plan. It is supplemented by an adjoining kitchen and bathroom. Four, square identical floor-to-ceiling windows provide unobstructed views of the surrounding natural environment, forming a “framed picture”. In good weather, the windows can be completely retracted into the ground, transforming the space into something resembling a pavilion. It is this feature as well as its homogeneous smooth exposed concrete walls, whose double-shelled structure also forms the monochrome envelope, that suspend the boundary between inside and out. A consistent use of concrete in the house’s walls, ceilings and floors lends the building its archaic character.

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Example 24

Office building conversion and extension Geneva, CH 2012 Architects: Francis Goetschmann Architecte, Geneva Structural engineers: Perreten & Milleret, Geneva

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A conversion and expansion of the Allianz company headquarters in Geneva had three main goals: to redefine the building’s main entrance, turn the existing and new buildings into a homogeneous ensemble, and in particular, to improve the office and residential complex’s energy balance, the latter not least because the company is in favour of energysaving policies. It was necessary to replace the entire facade to meet current thermal insulation standards. The new uniform building envelope extends across 140 metres, its south-western facade divided into two distinct areas. The ground floor, with its horizontal concrete louvre cladding, forms the building’s plinth. It compen-

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sates for the gradient of the adjoining street and shields the offices behind it from the effects of passing traffic. The two storeys above it are characterised by a storey-high glass facade between projecting exposed concrete slabs. Areas of glazing, scaled like the skin of a fish, trace the building’s contours in a saw-tooth pattern. Inside the compact office section, four square atria ensure an adequate supply of daylight. 1

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2≈ 8 mm toughened safety glass, aluminium frame Stainless steel ventilation grille 2.3 ≈ 2.3 mm with integrated insect screen Openable ventilation panel: anodised aluminium sheeting 2 mm, thermal insulation 60 mm, anodised aluminium sheeting 3 mm Exterior grating 40 mm Thermal insulation 90 mm Steel-reinforced concrete projection 300 mm Underfloor convection heater Interior grating, 25 mm Steel-reinforced concrete slab edge 890 mm Floor covering, carpet Double wooden floor 600/600/28 mm, elevated Steel-reinforced concrete slab 250 mm Plasterboard suspended ceiling Ground floor facade: steel-reinforced concrete louvres 330/120 mm

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Example 25

Boathouse Aure, N 2011 Sectional view Floor plan Scale 1:100

Architects: TYIN tegnestue Architects, Trondheim Assistants: Marianne Løbersli Sørstrøm, Yashar Hanstad

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The old boathouse near Aure on the Norwegian coast was built in the mid-18th century. However, its dilapidated condition made it necessary to pull it down and rebuild it. Eightmetre long steel beams, mounted on the existing rock structure, now hold up a new deck and boathouse. Its white-painted timber main support structure was mounted on site. The building envelope is made mainly of Norwegian pine impregnated under high pressure with an environmentally friendly, biological by-product of sugar production. This eliminates the need to treat the surface again in future, and the pine will develop a silver-grey patina over time. The boathouse’s inaccessible location made it expedient to reuse materials from the old boathouse. The interior cladding used to conceal crossed steel cables was partly made of old planks from the demolished boathouse. Flexibility during the construction process was crucial to the overall design. Old windows taken from a nearby farmhouse determined the spacing of the main beams. On the southern facade, the old corrugated sheet-metal roof now protects the outside of the doors from the harsh climate. On the inside, the doors are covered with backlit cotton sailcloth. Steelhinged joints enable them to be opened by folding them up, and when open, they form a protective roofed outdoor area.

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Example 26

House Hiroshima, J 2010 Architects: UID Architects, Hiroshima, Keisuke Maeda Structural engineer: Konishi Structural Engineers, Tokyo

This project to build a home for a mother and her two daughters was called "Nest". The house is embedded in the surrounding natural landscape like a bird’s nest. Exposed to the elements and temperatures that go down to 2 °C, it is equipped with insulation just 100 mm thick. Only in extreme cold or high winds do single-glazed sliding walls separate the living area from its central entry hall. When open, the glazed walls rest outside the facade and do not obstruct the spatial continuum of the interior. Despite its simply designed outward appearance, the building has a complex structure. Its access initially burrows deep into the ground, opening up in the middle of the house to a high space in the form of a garden in which a Japanese maple stretches to the sky through the open roof. Various levels enable users to see through the building into interacting individual areas, such as the space demarcated with wooden shelves housing sleeping and working areas through to the cooking area in the sunken dining and living area. Another bedroom and the bathroom are in the basement. A small staircase and reinforced concrete tunnel connect the areas, which are linked by openings and clear views.

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Example 27

Pavilion Geneva, CH 2008 Architects: Bakker & Blanc Architectes, Lausanne Assistants: Nuala Collins, Yves Dreyer, Thierry Sermet Structural engineers: Alho Systembau, Wikon

Geneva’s lakeside promenade, with its boat piers and fishing areas, is a place of high recreational value that invites pedestrians to stroll and linger. Over the years, however, structural problems such as increasing vehicle traffic on the lakeside roads and the heterogeneous look of the buildings on the promenade developed. Geneva’s city authorities launched a competition with the goal of creating uniform pavilions for lakeside services. The winning project by Bakker & Blanc Architectes proposed a single type of building for all usages, varying only in size and the design of their environment. This pavilion’s orientation, perpendicular to the lake, breaks with the structure of the buildings behind the quays and emphasises the promenade’s relationship to the residential quarters of Eaux-Vives and Pâquis. Open spaces between the small buildings are designed to allow views of the lake and create protected areas shielded from vehicle traffic. Erected on a square site, the basic type is a cube reduced to a minimum, with a slightly sloping gabled roof without projections or overhanging roof sections. The pavilions’ modular structure makes it possible to vary the type of structure for different kinds of uses. Their smallest possible unit, measuring 2.00 ≈ 2.80 metres, is a public toilet also equipped for use by the disabled. Another unit can be added to form a kiosk. A constructed prototype, which is used as a food stand, restaurant and kiosk, is the largest version planned, at 10 metres long. A textile sunshade, under whose shadow tables and chairs invite guests to linger, complements the cube. All that remains in the evenings when the folding hatches are closed is a simple structure in the public space. The pavilion’s steel frame has flexurally rigid corners. Folding hatches, which the operator can open and adjust individually using a gas pressure cylinder, allow views into the interior. Its external skin is made of bronze sheeting, whose patina shows traces of use, transport and weather. Mounted on sandwich panels, the sheets merge seamlessly to form a single surface.

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Example 28

Renovation and conversion of a high-rise government authority building Kiel, D 2013 Architects: bbp : architekten bda, Kiel Björn Bergfeld, Rolf Petersen Assistants: Nicole Birkholz, Marion Büter, Sven Friedrichs, Jan Szymkowiak Structural engineers: Oemig + Partner, Kiel Energy planning: KAplus, Eckernförde

Its chequerboard facade pattern is the first thing observers notice about this 13-storey high-rise. Behind a “curtain” of square projecting and retreating glass panels is the new headquarters of Kiel’s tax office (Finanzamt). Built in the 1970s with inadequate insulation, fire safety measures and soundproofing, it was in urgent need of renovation. During the conversion, its aluminium facade was completely replaced. To meet current insulation standards, resist wind loads and provide natural ventilation, the architects developed a casement window system with alternating “summer” and “winter” windows. The latter have an additional exterior fixed pane in the facade. Horizontal joints ensure the necessary exchange of fresh air. Their inner windowpane can be opened separately to make use of heated air in the facade cavity. Solar protection is positioned between the two panes of glass, protected from wind and weather. The “summer windows” function analogously, but here the outer panes of glass project about 15 cm out of the facade, which intensively ventilates the facade cavity and ensures a stable air temperature. A printed section on the outer pane’s upper area provides additional protection from the sun.

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Example 29

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Just a 40-minute drive from London is a new student residence complex with 205 apartments on the rural campus of Hatfield Royal Veterinary College in Hertfordshire. Nine structurally identical point blocks containing student apartments are grouped in pairs around green courtyards and squares. The three and four-storey blocks, all with an eastwest orientation, are linked with each other by an open-design access core. An elongated building completes the complex with a restaurant and conference and shared spaces. The six rooms on each storey are equipped with prefabricated bathrooms and a shared kitchen. Every room has a bay window, whose slanting installation prevents direct views into the interior. Each window has an openable anodised aluminium ventilation grille on one side. A mixed structure consisting of prefabricated concrete slabs, load-bearing brick walls and a steel frame in the attic storey forms the core of the residences. Their projecting bay windows were built with the help of steel frames anchored to prefabricated concrete elements. The stairwell core’s load-bearing structure is made of steel beams and concrete slabs. In the plinth area, the facades of the clearly defined building cubes are built with brick facing masonry, while the upper storeys are timber-clad. This hybrid building envelope is a design element and also relieves the monolithic building’s bulk. The use of red cedar and Bronsgroen brick is a nod to the location’s history. While the original campus building was built completely in brick, the newer buildings are made mainly of timber. Its planners worked together with an artist to create the perforated bronze-coloured aluminium cladding of the prefabricated stairwells, which coloured light transforms into oversized lanterns at night.

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Example 30

Office building 3

Ballerup, DK 2013 Architects: Arkitema Architects, Aarhus Structural engineers: midtconsult, Herning

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This modern administration building for Siemens’ new company headquarters on the outskirts of Copenhagen was inaugurated in 2014 and now houses workplaces for the company’s 900 employees. Horizontal rows of windows and alternating white and dark-grey concrete sandwich slab facade cladding give the five-storey building complex a dynamic look. Its ground floor accommodates public functions for employees and guests, including a reception area, canteen, an exhibition space, classrooms and training facilities. A light central atrium with a striking stair and

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lift tower, access bridges connecting the office floors and shared spaces form the building’s core. As well as providing the necessary access, it offers interesting and unexpected visual connections between individual office levels. Flexible workstations are grouped around integrated central zones in the form of recreation areas, conference rooms, kitchenettes and copier rooms. A large glass roof made up of six rows of modular skylights spans the atrium and admits plenty of daylight. Each of the 228 skylights measures 0.90 by 2.20 metres. The glass fibre

and polyurethane composite material used in the window frames provides low levels of thermal conductivity, prevents thermal bridges and ensures very low U values. All the window elements in the modular skylight system have integrated white sunscreen blinds. In contrast to dark materials, they admit abundant light, ensuring adequate and pleasant levels of daylight inside. A special system automatically controls the blinds, reacting to temperature and incident light, and protecting the atrium from extreme heat and blinding sunlight without impairing the quality of the daylight.

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Authors Jan Cremers (Editor) Born 1971 Studied architecture at the Universität Karlsruhe (TH) and Westminster University London 1999 – 2002 Worked as an architect, incl. at Koch+Partner, Munich 2002 – 2006 Research assistant to the Chair of Building Technology, Prof. Thomas Herzog, Technical University of Munich 2006 Awarded a doctorate at the Technical University of Munich 2006 – 2008 Worked at SolarNext AG, Rimsting, including periods on the Board of Management From 2008 Director of Technology at Hightex GmbH, Rimsting From 2008 Professor of building technology and integrated architecture at Hochschule für Technik Stuttgart, University of Applied Sciences From 2011 First Studiendekan (head of courses) of the new Bachelor’s “KlimaEngineering” course at Hochschule für Technik Stuttgart, University of Applied Sciences Markus Binder Born 1970 Studied architecture at the University of Stuttgart, building physics at the Stuttgart University of Applied Sciences 1998 – 2011 Collaboration and project management for various architecture firms in the Stuttgart area 2007– 2011 Academic member at Stuttgart University of Applied Sciences, Department of Building Physics 2009 – 2011 Lectureship in building physics at the Staatliche Akademie der Bildenden Künste Stuttgart (State Academy of Fine Arts Stuttgart) 2011 Visiting professor for building construction and design, in particular, climate-friendly architecture at the Hochschule für Technik Stuttgart, University of Applied Sciences Since 2012 Professor for integrated building technology at the Hochschule für Technik Stuttgart, University of Applied Sciences Since 2013 Partner at CAPE climate architecture physics energy Peter Bonfig Born 1960 1980 –1986 Studied architecture at Technische Universität Braunschweig (Braunschweig University of Technology), Eidgenössische Technische Hochschule Zürich (ETH Zurich) and Technical University of Munich (master’s degree) 1988 –1993 Collaboration with the architecture firm of Herzog + Partner in Munich Since 1991 Own projects and activities as a freelance architect, including professional architectural photography 1995 –1998 Research fellow at the University of Stuttgart, Institute for Design and Engineering 2001– 2007 Research assistant at Technical University of Munich for the Chair of Building Technology and the Chair of Industrial Design 2007 PhD at Technical University of Munich 2008 – 2009 BlighVollerNield Architecture in Melbourne, Australia 2009 – 2010 Lectureship at Technical University of Munich Teaching activity abroad: Royal Academy of Fine Arts in Copenhagen, University of Texas at Austin, Kyoto Institute of Technology Since 2012 Development of research projects with the Hochschule für Technik Stuttgart, University of Applied Sciences, among others

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Joost Hartwig Born 1980 Studied architecture at Technical University of Darmstadt 2007– 2012 Research fellow for design and energyefficient construction under Professor Manfred Hegger at Technical University of Darmstadt, with a research focus on life cycle analysis and sustainability assessment of buildings 2007– 2013 Worked at HHS Planer + Architekten AG, Kassel Since 2008 Auditor for the sustainability certification system of the German Sustainable Building Council (DGNB), engaged as a member of the “life-cycle assessment” expert group, among others Winter semester 2009/2010 Lectureship at the Erfurt University of Applied Sciences 2010 – 2013 Lectures at the Umeå School of Architecture, Sweden 2013 Lectureship at the Frankfurt University of Applied Sciences 2014 – 2016 Visiting professor for life-cycle assessment, sustainability assessment and energy efficiency for buildings at the Frankfurt University of Applied Sciences Since 2011 Managing Director of ina Planungsgesellschaft mbH Since July 2013 Board member at AktivPlus e. V. Hermann Klos Born 1954 After completing high school with Abitur, trained as a carpenter and joiner before working for 26 years as a master joiner and Managing Director of Holzmanufaktur Rottweil GmbH, which currently has around 80 employees working mainly in the area of historic building conservation in southern Germany and Switzerland. Provides expert reports and project planning for construction work and has lectured and taught on historic building conservation issues. Member of various associations working in the areas of historic buildings conservation, architectural cultural heritage (“Baukultur”) and building preservation Member of netzwerk.kulturgut.org Ulrich Sieberath Born 1957 Diplom (engineering degree) in Wood Technology at Rosenheim University of Applied Sciences From 1982 worked at the ift Rosenheim, becoming head of the Türentechnik und Einbruchsicherheit (door technologies and break-in security) department From 1995 head of the ift Rosenheim certification body for Quality Management Systems and Products From 2000 Coordinator of business sectors at the ift Rosenheim From 2002 Assistant Director of the Institute From February 2004 Director of the ift Rosenheim From October 2012 honorary professor at the Rosenheim University of Applied Sciences Other professional functions and activities: • Lecturer at the Rosenheim University of Applied Sciences • Participation in and chairman of many standardisation committees /sector groups: Chair of the NA 005-09-01 mirror (standards) committee on TC33, Chair of CEN TC33 WG1 (window and door) standards committee Chair of the SG06 (windows, doors, gates) and SG 06 D standards committees; member of the mirror committee of the Advisory Group of Notified Bodies • Member of the IHK Examinations Commission for sworn technical experts • Expert technical consultant for accreditation bodies: DAkkS Berlin and the Federal Institute of Metrology (Eidgenössisches Amt für Messwesen) (Switzerland) Main areas of expertise: Structural components testing windows / doors /facades, Materials testing wood / derived timber products /glass, break-in security for windows / roller shutters / doors / facades /glass /fittings

Wolfgang Jehl Born 1963 1986 –1991 Diplom (engineering degree) in Wood Technology at Rosenheim University of Applied Sciences, followed by work as a metal worker, carpenter, joiner and in prefabricated house construction From 1991 worked at the ift Rosenheim in the areas of • 1991– 2002 Expert reports, Property Surveillance • 2000 – 2002 Head of the Expert Reports department • 2003 – 2010 Assistant Director of the testing body of the ift Zentrum Fenster und Fassaden (Window and facade centre) • Since 07/2010 Product engineer and Assistant Director of the testing body in the Construction Materials & Semi-finished Products Division in the areas of laminated glazing, external connections and structural connections Other professional activities: • Chair of the NA 005-02-17 AA standards committee on “Non-metallic foam strapping” • Member of the NA 005-02 FBR steering committee on “Sealing and moisture proofing” • Lecturer at the Rosenheim University of Applied Sciences as part of EDPRO Ingo Leuschner Born 1972 1991–1997 Diplom (engineering degree) in Wood Technology at the Rosenheim University of Applied Sciences Since 1997 he has worked at the ift Rosenheim in the roles of • Technical Assistant to the Institute Director • Sachverständigenzentrum (Expert opinion centre) • Head of various research projects (on wooden facades, fittings technologies, composite structures and surfaces technologies) • 2005 – 2010 Assistant Director of R&D • 2010 – 2013 Responsible for enterprise development and innovation management • since 2014 Director of the ift Sachverständigenzentrum (Expert opinion centre) Other professional activities: • Speaking and lecturing Elke Sohn Born 1966 Architectural historian and theoretician Studied architecture and urban development with subsequent PhD in 2005 at the Hamburg University of Fine Arts 2007 – 2012 Research fellow at HafenCity University Hamburg and University of Technology Kaiserslautern 2006 – 2009 Deputy professor at the University of Applied Sciences in Saarbrucken Since 2012 Professor for building history and architectural theory at the Hochschule für Technik Stuttgart, University of Applied Sciences Research and publication focus: history and theory of modern architecture Thomas Stark Born 1970 Banker at Deutsche Bank AG Studied architecture with subsequent PhD at the University of Stuttgart 2003 – 2005 Research fellow Institute of Building Technology, Construction and Design, Prof. Stefan Behling, University of Stuttgart 2005 – 2008 Research fellow for design and energyefficient construction under Professor Manfred Hegger at Technical University of Darmstadt 2003 Founder ee-plan, Stuttgart Since 2008 Professor for energy-efficient construction at HTWG Konstanz, Faculty of Architecture and Design Since 2009 Managing partner at ee concept GmbH, Darmstadt / Tübingen

Acknowledgements

Ordinances, guidelines and standards

Jan Cremers would like to thank his family for the patience and time they contributed to this extensive book project and his father Stefan Cremers for making him aware of this topic while he was still a child, for their many fruitful discussions and for the superb treasury of images. He would further like to thank his dedicated co-authors and colleagues at the Hochschule für Technik Stuttgart (University of Applied Sciences) for their expert support and advice, in particular Peter Krebs, Andreas Drechsler and Heinz-Martin Fischer.

The EU has issued guidelines on a number of products to ensure the safety and health of users. These guidelines must be incorporated into binding laws and ordinances in member states. These guidelines do not contain any technical details, only binding basic requirements. The technical specifications for them are set out in the relevant technical rules and in harmonised standards applicable across Europe (EN standards). General technical rules are practical guides and tools for use in everyday work. They are not legal regulations but can be used to help make decisions, are guidelines for faultless technical performance, and /or put the content of ordinances in more concrete terms. Anyone is free to use technical rules. Only when they are incorporated into laws, ordinances or regulations (e. g. in construction law) or if binding individual standards between parties to a contract are agreed on in that contract do they become legally binding. Technical rules include DIN standards, VDI guidelines and other works referred to as “generally accepted technical rules and standards” (e. g. the technical rules for dangerous goods (Technische Regeln für Gefahrstoffe – TRGS). Standards are divided into product, application and test standards. They often refer only to a specific group of materials or products. These standards are based on testing and research methods relevant to the respective materials. The newest version of a standard, which should represent state-of-the-art technology, is always the valid one. New or revised standards are made available to the public for discussion in the form of a draft standard, then subsequently adopted as standards. A standard's origins and scope of application are indicated in its title. DIN plus a number (e. g. DIN 4108) designates a standard of mainly national significance (draft standards are prefixed with an 'E' and pre-standards with a “V”). DIN EN plus a number (e. g. DIN EN 335) refers to a German version of a European standard that has been adopted by CEN, the European standards organisation, unchanged. DIN EN ISO (e. g. DIN EN ISO 13 786) indicates national, European and worldwide scope of application. European standards are developed on the basis of International Standards Organisation (ISO) standards and adopted as DIN standards. DIN ISO (e. g. DIN ISO 2424) standards are ISO standards that have been adopted unchanged as national standards. The list below is a selection of ordinances, guidelines and standards representing current state-of-the-art technology (November 2014). Only standards specification sheets with the most recent issue date from the DIN (Deutsches Institut für Normung e. V.) are binding.

Certain passages from the entry “The historic development of the window – from its origins through to the early modern era” (see p. 12ff.) by Hermann Klos have already appeared in: “Huckfeldt, Tobias; Wenk, Hans-Joachim (eds.): Holzfenster – Konstruktion, Schäden, Sanierung, Wartung. Cologne 2009, p. 13 – 32”. Hermann Klos and the publisher would like to cordially thank the Rudolf Müller Verlag for their kind permission to reproduce this work here and for the good cooperative relationship. The authors and publishers would also like to thank the following people and companies for providing information, images and /or drawings for this book. AEREX HaustechnikSysteme GmbH, VillingenSchwenningen (D) Aereco GmbH, Hofheim-Wallau (D) Andreas Wagner, Karlsruhe (D) Aumüller Aumatic GmbH, Thierhaupten (D) Daniel Westenberger, Munich (D) EControl-Glas GmbH & Co. KG, Plauen (D) ERCO GmbH, Lüdenscheid (D) Fiberline Composites A/S, Middelfart (DK) Flachglas Wernberg GmbH, Wernberg-Köblitz (D) Gerd Gassmann, Karlsruhe (D) Glas Trösch AG Isolierglas, Bützberg (CH) GlassX AG, Zurich (CH) Gretsch-Unitas GmbH, Ditzingen (D) Hautau GmbH, Helpsen (D) Hofman Dujardin Architecten, Amsterdam (NL) Innoperform GmbH, Preititz (D) Internorm International GmbH, Traun (A) Interpane, Lauenförde (D) I-S-T AG, Prutting (D) KNEER-SÜDFENSTER, Westerheim (D) LTG Aktiengesellschaft, Stuttgart (D) LUNOS Lüftungstechnik GmbH für Raumluftsysteme, Berlin (D) Okalux GmbH, Marktheidenfeld (D) Otto Fuchs KG, Meinerzhagen Raico, Pfaffenhausen (D) Renson Ventilation, Waregem (B) Roto Frank Bauelemente GmbH, Bad Mergentheim (D) Saint-Gobain Glass Deutschland GmbH, Aachen (D) Schüco International KG, Bielefeld (D) Sebastian Fiedler, Frankfurt (D) Stabalux GmbH, Bonn (D) Steffen Jäger, Braunschweig (D) Uniglas GmbH & Co. KG, Montabaur (D) VELUX Deutschland GmbH, Hamburg (D) WAREMA Renkhoff SE, Marktheidenfeld (D) Werner Lang, Munich (D) Wicona, Ulm (D) ZAE Bayern e. V., Würzburg (D)

Merkblätter (technical data sheets) of the Verband der Fenster- und Fassadenhersteller (VFF) Merkblatt (technical data sheet): Gebäudeeingänge mit großem Publikumsverkehr (Building entrances with heavy traffic), Züricher Energieberatung / Bundesamt für Energie 1998 Richtlinie zur Beurteilung der visuellen Qualität von Glas für das Bauwesen (Guideline for evaluating the visual quality of glass in buildings), drawn up by the Technical Advisory Board of the Institut des Glaserhandwerks für Verglasungstechnik und Fensterbau (Institute of Glaziers), Hadamar and by the Technical Committee of the Bundesverband Flachglas e. V. (Federal German Flat Glass Industry Association), Troisdorf, as of 5-2009. Richtlinien der RAL-Gütergemeinschaft Fenster und Haustüren (Guidelines of the RAL Window and Residential Door Quality Assurance Association) Richtlinien des Bundesinnungsverbands des Glaserhandwerks (Guidelines of the Federal Association of Glazing Trades) Richtlinien des Bundesverband Flachglas (Guidelines of the Federal German Flat Glass Industry Association) Richtlinien des Bundesverband Holz und Kunststoff (Guidelines of the German Wood and Plastics Industry Association) Richtlinien Technische Richtlinien des Glaserhandwerks

(Technical guidelines of the Association of Glazing Trades) Technische Regeln für die Bemessung und die Ausführung punktförmig gelagerter Verglasungen – TRPV (Technical rules for measuring and building pointsupported glazing), DIBt, 8-2006 Technische Regeln für die Verwendung von absturzsichernden Verglasungen –TRAV (Technical rules for the use of safety barrier glazing), Deutsches Institut für Bautechnik (DIBt) (German Institute for Civil Engineering), 1-2003, now replaced by the new Glass in Building standard, DIN 18 008-4 Technische Regeln für die Verwendung von linienförmig gelagerten Verglasungen – TRLV (Technical rules for the use of linear-supported glass), Deutsches Institut für Bautechnik (DIBt) (German Institute for Civil Engineering), 8-2006, now replaced by the new Glass in Building standard, DIN 18 008-2 Verordnung über energiesparenden Wärmeschutz und energiesparende Anlagentechnik bei Gebäuden (Ordinance on energy saving thermal insulation and energy saving systems technology for buildings) (Energy Saving Ordinance - Energieeinsparverordnung – EnEV) Second Amendment to the Energy Saving Ordinance of 18 November 2013. (EnEV 2014) Overarching standards and regulations DIN 1946-6 Ventilation and air conditioning – Part 6: Ventilation for residential buildings – General requirements, requirements for measuring, performance and labelling, delivery /acceptance (certification) and maintenance. 2009-05 DIN 18 055 Criteria for the use of exterior windows and doors in accordance with DIN EN 14 351-1. 2014-11 DIN EN 14 351-1 Windows and doors – Product standard, performance characteristics – Part 1: Windows and external pedestrian doors without fire protection and /or smoke-proof characteristics. 2010-08 DIN EN 14 351-2 Draft standard. Windows and doors – Product standard, performance characteristics – Part 2: Interior doors without fire protection and/or smoke-proof characteristics. 2014-06 DIN 1960 German construction contract procedures (VOB) – Part A: General provisions relating to the award of construction contracts. 2012-09 DIN 1961 German construction contract procedures (VOB) – Part B: Conditions of contract relating to the execution of construction work. 2012-09 DIN 18 299 German construction contract procedures (VOB) – Part C: General technical specifications in construction contracts (ATV) – General rules for construction work of any kind. 2012-09 DIN 58 125 School buildings – technical construction requirements to prevent accidents. 2002-07 DIN 18 040-1 Construction of accessible buildings – Design principles – Part 1: Publicly accessible buildings. 2010-10 DIN 18 040-2 Construction of accessible buildings – Design principles – Part 2: Dwellings. 2011-09 DIN EN 1991-1-1 Eurocode 1: Actions on structures – Part 1-1: General actions – Densities, self-weight, imposed loads on wooden structures. 2010-12 DIN EN 12 216 Shutters and blinds – Terminology, designations and definitions. 2002-11 DIN EN 12 519 Windows and doors – Terminology. 2004-06 Materials DIN 18 008-1 Glass in building – Design and construction rules – Part 1: Terminology and general fundamentals. 2010-12 DIN 18 008-2 Glass in building – Design and construction rules – Part 2: Glazing systems with linear support. 2010-12 DIN 18 008-2 Corrigendum 1 to Glass in building – Design and construction rules – Part 2: Glazing systems with linear support, Corrigendum to DIN 18 008-2:2010-12. 2011-04 DIN 18 008-3 Glass in building – Design and construction rules – Part 3: Point-fixed glazing. 2013-07 DIN 18 008-4 Glass in building – Design and construction rules – Part 4: Additional requirements for safety barrier glazing. 2013-07

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DIN 18 008-5 Glass in building – Design and construction rules – Part 5: Additional requirements for walk-on glazing. 2013-07 DIN EN 356 Glass in building – Security glazing – Testing and classification of resistance against manual. 2000-02 DIN EN 357 Glass in building – Fire-resistant glazed elements with transparent or translucent glass – Classification of fire resistance. 2005-02 DIN EN 572-1 Glass in building – Basic lime soda silicate glass products – Part 1: Definitions and general physical and mechanical characteristics. 2012-11 DIN EN 572-2 Glass in building – Basic lime soda silicate glass products – Part 2: Float glass. 2012-11 DIN EN 673 Glass in building – Definition of thermal transmittance (U value) – Calculation method. 2011-04 DIN EN 1096-4 Glass in building – Coated glass – Part 4: Evaluation of conformity /Product standard. 2005-01 DIN EN 1279-1 Glass in building – Insulating glass units – Part 1: Generalities, system description, rules for substitution, tolerances and visual quality. 2004-08 DIN EN 1279-2 Glass in building – Insulating glass units – Part 2: Long-term test method and requirements for moisture penetration. 2003-06 DIN EN 1279-3 Glass in building – Insulating glass units – Part 3: Long-term test method and requirements for gas leakage rate and gas concentration tolerances. 2003-05 DIN EN 13 022-1 Glass in building – Laminated glass – Part 1: Glass products for Structural Sealant Glazing (SSG) Glass structures for single and multiple-pane units, with or without dead weight load bearing. 2014-08 DIN EN 13 022-2 Glass in building – Laminated glass – Part 2: Regulations for Structural Sealant Glazing (SSG) Glass structures. 2014-08 DIN EN 14 449 Glass in building – Laminated glass and laminated safety glass – conformity evaluation /product standard. 2005-07 DIN EN ISO 12 543-2 Glass in building – Laminated glass and laminated safety glass – Part 2: Laminated safety glass (ISO 12 543-2:2011). 2011-12 DIN EN ISO 12 543-3 Glass in building – Laminated glass and laminated safety glass – Part 3: Laminated glass (ISO 12 543-3:2011). 2011-12 DIN EN ISO 12 543-4 Glass in building – Laminated glass and laminated safety glass – Part 4: Test methods for durability (ISO 12 543-4:2011). 2011-12 DIN EN ISO 12 543-5 Glass in building – Laminated glass and laminated safety glass – Part 5: Dimensions and edge finishing (ISO 12 543-5:2011). 2011-12 DIN EN ISO 12 543-6 Glass in building – Laminated glass and laminated safety glass – Part 6: Appearance (ISO 12 543-6:2011 + Cor. 1:2012). 2012-09 EN 14 024 2004-10 Metal profiles with thermal barriers– Mechanical performance Building physics: requirements and characteristics DIN 4108 Supplementary sheet 2 Thermal insulation and energy economy in buildings – Thermal bridges – Examples of planning and performance. 2006-03 DIN 4108-2 Thermal insulation and energy economy in buildings – Part 2: Minimum requirements for thermal insulation. 2013-02 DIN 4108-3 Thermal insulation and energy economy in buildings – Part 3: Protection against moisture, subject to climate conditions, Requirements and directions for design and construction. 2001-07 DIN 4108-3 Draft standard, Thermal insulation and energy economy in buildings – Part 3: Protection against moisture, subject to climate conditions, Requirements and directions for design and construction. 2012-01 DIN 4108-4 Thermal insulation and energy economy in buildings – Part 4: Hygrothermal design values. 2013-02 DIN 4108-7 Thermal insulation and energy economy in buildings – Part 7: Air-tightness of buildings – Requirements, recommendations and examples of planning an performance. 2011-01 DIN 4109 Sound insulation in buildings; Requirements and certification. 1989-11 DIN 4109 Supplementary sheet 1, Sound insulation in buildings; Construction examples and calculation methods. 1989-11

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DIN 4109 Supplementary sheet 1/A1 Sound insulation in buildings – Construction examples and calculation methods; Amendment A1. 2003-09 DIN 4109 Supplementary sheet 1/A2 Sound insulation in buildings – Supplementary sheet 1: Construction examples and calculation methods; Amendment A2. 2010-02 DIN 4109 Supplementary sheet 2 Sound insulation in buildings; Guidelines for planning and execution; Proposals for increased sound insulation; Recommendations for sound insulation in personal living and working areas. 1989-11 DIN 4109 Supplementary sheet 3, Sound insulation in buildings – Calculation of R'w, R for the verification of suitability as per DIN 4109 on the basis of the sound reduction index Rw determined in a laboratory testing. 1996-06 DIN EN 12 207 Windows and doors – Air-tightness – Classification. 2000-06 DIN EN 12 208 Windows and doors – Resistance to driving rain – Classification. 2000-06 DIN EN ISO 10 077-1 Thermal insulation behaviour of windows, doors and shutters – Calculation of thermal transmittance – Part 1: Generalities (ISO 10 077-1:2006 + Cor. 1:2009). 2010-05 DIN EN ISO 10 077-2 Thermal insulation behaviour of windows, doors, shutter and blinds – Calculation of thermal transmittance – Part 2: Numerical method for frames (ISO 10 077-2:2012). 2012-06 Protection from fire and smoke: requirements and characteristics DIN EN 12 101-2 Draft standard, Smoke and heat control systems – Part 2: Specifications for natural smoke and heat exhaust ventilators. 2014-09 DIN EN 13 501-1 Fire classification of construction products and building elements – Part 1: Classification using data from reaction to fire tests. 2010-01 DIN EN 13 501-5 Fire classification of construction products and building elements – Part 5: Classification using data from external fire exposure to roof tests. 2010-02 DIN EN 14 600 Doorsets and openable windows with fire resisting and /or smoke control characteristics – Requirements and classifications. 2006-03 DIN EN 16 034 Draft standard, Pedestrian doorsets, industrial, commercial garage doors and openable windows – Product standard, performance characteristics – Fire resistance and /or smoke control characteristics. 2014-03 Due to be withdrawn and replaced by 2014-12 by DIN EN 16 034, 2014-12 issue Mechanical properties: requirements and characteristics DIN 18 257 Building hardware – Security plates – Definitions, measurements, requirements, marking. 2003-03 DIN 18 267 Window handles – Clickable and lockable window handles. 2005-01 DIN 18 267 Corrigendum 1, 2005-10 Window handles – Clickable and lockable window handles – Corrigendum to DIN 18 267:2005-01 DIN EN 179 Building hardware – Emergency exit devices operated by a lever, handle or push pad for doors in escape routes – Requirements and test methods. 2008-04 DIN EN 1125 Building hardware – Panic exit devices operated by a horizontal bar for doors on escape routes – Requirements and test methods. 2008-04 DIN EN 1627 Pedestrian doorsets, windows, curtain walling, grilles and shutters – Burglar resistance – Requirements and classification. 2011-09 DIN EN 1628 Pedestrian doorsets, windows, curtain walling, grilles and shutters – Burglar resistance – Method for testing the determination of resistance under static loading. 2011-09 DIN EN 1629 2011-09 Pedestrian doorsets, windows, curtain walling, grilles and shutters – Burglar resistance – Method for testing the determination of resistance under static loading under dynamic loading. DIN EN 1630 Pedestrian doorsets, windows, curtain walling, grilles and shutters – Burglar resistance – Method for testing the determination of resistance to attempted manual break-ins. 2011-09

DIN EN 12 210 Windows and doors – Resistance to wind loads – Classification (includes Corrigendum AC: 2002). 2003-08 DIN EN 12 400 Windows and doors – Mechanical durability – Requirements and classification. Building hardware 2003-08 EN 13 126-1 Building hardware for windows and doorheight windows – Requirements and test methods – Part 1: Requirements common to all types of hardware. 2012-02 Installation DIN 18 195-4 Waterproofing of buildings – Part 4: Waterproofing against ground moisture (capillary water, retained water) and non-accumulating seepage water on floor slabs and walls, design and execution. 2011-12 DIN 18 195-5 Waterproofing of buildings – Part 5: Waterproofing against non-pressing water on floors and in wet areas, design and execution. 2011-12 DIN 18 195-6 Waterproofing of buildings – Part 6: Waterproofing gegen von außen drückendes Wasser und aufstauendes Sickerwasser, design and execution. 2011-12 DIN 18 195-9 Waterproofing of buildings – Part 9: Penetrations, transitions, connections and endings. 2010-05 DIN 18 195 Supplementary sheet 1, Waterproofing of buildings – Examples of sealing configuration. 2011-03 DIN 18 202 Tolerances in building construction – Buildings. 2013-04 DIN 18 203-1 Tolerances in building construction – Part 1: Prefabricated concrete, steel reinforced concrete and pre-stressed concrete components. 1997-04 DIN 18 203-3 Tolerances in building construction – Part 3: Building components of wood and derived timber products. 2008-08 DIN 18 540 Sealing of exterior wall joints in building construction using joint sealants. 2006-12 DIN 18 542 Sealing of exterior wall joints in building construction using impregnated plastic foam joint sealing strips– Impregnated joint sealing strips – Requirements and testing. 2009-07 DIN EN ISO 13 788 Hygrothermal performance of building components and building elements – Internal surface temperature to avoid critical surface humidity and interstitial condensation – Calculation methods. 2013-05 DIN EN 13 829 Thermal performance of buildings – Determination of air permeability of buildings – Fan pressurization method (ISO 9972:1996, modified). 2001-02 DIN EN 15 651-1 Sealants for non-structural use in buildings and pedestrian walkways – Part 1: Sealants for facade elements. 2012-12 DIN EN 15 651-2 Sealants for non-structural use in buildings and pedestrian walkways – Part 2: Sealants for glazing. 2012-12 Shutters, blinds and awnings (for sun protection etc.) DIN EN 13 120 Internal blinds – Performance requirements including safety. 2014-09 DIN EN 13 659 Draft standard, Shutters and external Venetian blinds – Performance requirements including safety. 2014-10 DIN V 18 073 Pre-standard, Roller shutters, awnings, rolling doors and other blinds and shutters in buildings – Terms and requirements. 2008-05 DIN EN 12 216 Shutters external and internal blinds – Terminology, glossary and definitions. 2002-11 DIN EN 13 363-1 Solar protection devices in combination with glazing – Calculation of solar and light transmittance – Part 1: Simplified method. 2007-09 DIN EN 13 363-2 Solar protection devices in combination with glazing – Calculation of solar and light transmittance – Part 2: Detailed calculation method. 2005-06 DIN EN 13 363-2 Corrigendum, 1 Solar protection devices in combination with glazing – Calculation of solar and light transmittance – Part 2: Detailed calculation method. 2007-04 DIN EN 13 561 External blinds and awnings – Performance requirements including safety. 2009-01 DIN EN 13 659 Shutters and external Venetian blinds – Performance requirements including safety. 2009-01 DIN EN 14 501 Blinds and shutters – Thermal and visual comfort – Performance characteristics and classification. 2006-02

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Schneck, Adolf: Fenster aus Holz und Metall. Stuttgart, 1953/1963 Schock-Werner, Barbara; Bingenheimer, Klaus: Fenster und Türen in historischen Wehr und Wohnbauten. Stuttgart, 1995 Schrader, Mila: Fenster, Glas und Beschläge als historisches Baumaterial, ein Materialleitfaden und Ratgeber. Suderburg-Hösseringen, 2001 Schumacher, Michael; Schaeffer, Oliver; Vogt, MichaelMarcus: move – Architektur in Bewegung – Dynamische Komponenten und Bauteile. Basel, 2010 Selbmann, Rolf: Eine Kulturgeschichte des Fensters: Von der Antike bis zur Moderne. Berlin, 2010 Selle, Gert: Öffnen und Schließen. Über alte und neue Bezüge zum Raum. In Wolkenkuckucksheim, 01/2004 Sieberath, Ulrich; Niemöller, Christian (eds.): Kommentar zur DIN EN 14 351-1, Fenster und Türen – Produktnorm, Leistungseigenschaften – Teil 1: Fenster und Außentüren ohne Eigenschaften bezüglich Feuerschutz und / oder Rauchdichtheit, mit Ergänzung (Amendment) A1:2010. Rosenheim / Stuttgart, 2010 Sigwart, R.: Luftdurchlässigkeit von Holz- und Stahlfenstern. Munich, 1932 Steuer, Heiko: Freiburg und das Bild der Städte um 1100 im Spiegel der Archäologie. In: Freiburg 1091–1120. Neue Forschungen zu den Anfängen der Stadt. Ed. by Schadek, Hans; Zotz, Thomas. Freiburg 1995, p. 79 –124 Tanner, Erika: Die Bauernhäuser des Kanton Thurgau. Schweizerische Gesellschaft für Volkskunde. Basel, 1998 Tsukamoto, Yoshiharu et al.: WindowScape – Window Behaviourology. Tokyo Institute of Technology. Singapore, 2012 Uhlig, Günther; Kohler, Niklaus; Schneider, Lothar (eds.): Fenster. Architektur und Technologie im Dialog. Braunschweig, 1994 Veith, Jürgen; Lerch, Patrick: Gesundheit und Umweltschutz bei Bauprodukten. Die europäische Normung zur Bauprodukten-Richtlinie. Fraunhofer IRB Verlag. Stuttgart, 2008 Verband Fenster+Fassade und Bundesverband Flachglas e. V.: Mehr Energie sparen mit neuen Fenstern. Update of March 2014 of the study “Im neuen Licht: Energetische Modernisierung von alten Fenstern”. Frankfurt am Main /Troisdorf, 03/2014 Vereinigung der Landesdenkmalpfleger in der Bundesrepublik Deutschland: Arbeitsblatt 8. Hinweise für die Behandlung historischer Fenster bei Baudenkmälern. Wiesbaden, 1991 Voss, Karsten: Energieoptimiertes Bauen: Dezentrale Lüftung in Bürogebäuden – Mikroklimatische und baukonstruktive Einflüsse. Schlussbericht. Förderkennzeichen 0327386A. University of Wuppertal, December 2010 Wagner, Andreas et al.: Energieeffiziente Fenster und Verglasungen. Fraunhofer IRB-Verlag /BINE. Stuttgart, 2013 Weber, Marga: Antike Badekultur. Munich, 1999 Weizenhöfer, Günther: Leitfaden Türplanung. Leitfaden Türplanung – Anforderungen, Türtechnik und Darstellung in Türlisten. Berlin, 2015 Wendehorst, Reinhard: Baustoffkunde. Hanover, 2004 Westenberger, Daniel: Untersuchungen zu Vertikalschiebefenstern. Dissertation with Prof. Thomas Herzog at the Technical University of Munich, 2005 Westenberger, Daniel: Vertikale Schiebefenster. Beitrag in zwei Teilen. In: Fassade /Facade 2+3/2002 Wickop, Walther: Fenster, Türen, Tore aus Holz und Eisen. Berlin, 1955. Wicona Planungshandbuch Fenster Wuppertal Institut für Klima, Umwelt, Energie GmbH: Ressourcensicherheit und Ressourceneffizienz – Wege aus der Rohstoffkrise. Policy Paper zu Arbeitspaket 7 des Projekts “Materialeffizienz und Ressourcenschonung” (MaRess). Wuppertal, 2009. Ziegler, Peter: Kulturraum Zürichsee. Stäfa, 1998 Zimmermann, Markus: Fenster im Fenster. In DETAIL 4/1996, p. 484 – 489 Zöllner, Andreas: Experimentelle und theoretische Untersuchungen des kombinierten Wärmetransports in Doppelfassaden, Dissertation, Munich 2001

Image credits The authors and publishers would like to cordially thank everyone who contributed to the creation of this book by offering us images, allowing us to reproduce them, and providing information. All the drawings in this work were produced specifically for it. Photos that are not credited come from the authors’ and architects’ archives, are works photos, or come from the DETAIL magazine archive. Despite our best efforts, we have not been able to identify some owners of photos and images but their copyrights remain unaffected. Please contact us if you have any information on this subject. The figures shown refer to image numbers.

Part A A

Christian Schittich, Munich

Openings in buildings A 1.1 Schneck, Adolf: Fenster aus Holz und Metall. Stuttgart 1953, p. VI A 1.2 Stefan Cremers, Karlsruhe A 1.3 Jan Cremers, Munich A 1.4 Jeroen Musch, Amsterdam A 1.5 Martin Kunze / IBA Hamburg GmbH A 1.6 Pedro Pegenaute, Pamplona A 1.7 Werner Huthmacher, Berlin A 1.8 Marion Lafogler, Bolzano A 1.9 Naquib Hossain, Dakar A 1.10 Roger Frei, Zurich A 1.11 Jan Cremers, Munich The historic development of the window – from its origins through to the early modern era A 2.1 AP Photo / Manchester University / Alan Sorrell, HO A 2.2 from: Dalarun, Jacques (Ed.): Das leuchtende Mittelalter. Darmstadt 2011, p. 57 A 2.3 from: Gutschler, Daniel: Karolingische Holzbauten im Norden der Fraumünsterabtei. 1984, p. 216 A 2.4 from: Baatz, Dietwulf: Fensterglastypen, Glasfenster und Architektur. Mainz 1991 A 2.5 from: Kirchberger 1995, p. 79 A 2.6 Denkmalpflege in Hessen 1/1990, p. 34 A 2.7 from: Descoeudres, Georges; Keck, Gabriele; Wadsack, Franz: Das Haus Nideröst in Schwyz, Archäologische Untersuchung 1998 – 2001 Published in: Mitteilungen des historischen Vereins des Kantons Schwyz. Booklet 94/2002, p. 243 A 2.8 Holzmanufaktur Rottweil, Hermann Klos, Neckartal 159, 78628 Rottweil A 2.9 Ulrike Gollnick, Moudon A 2.10, 11 from: Ewald, Rainer; Köhle-Hezinger, Christel; Könekamp, Jörg (Ed.): Stadthaus-Architektur und Alltag in Esslingen seit dem 14. Jahrhundert: Hafenmarkt 8 und 10. Weissenhorn 1992, p. 45 A 2.13 from: Das große Lexikon der Malerei. Braunschweig 1982 A 2.15, 16 Robert Campin, Verkündigung: Brüssel Musées Royaux A 2.17 from: Dalarun, Jacques (Ed.): Das leuchtende Mittelalter. Darmstadt 2011, p. 154 A 2.18 as for A 2.8 A 2.19 from: Schock-Werner, Barbara; Bingenheimer, Klaus: Fenster und Türen in historischen Wehr und Wohnbauten. Stuttgart 1995, p. 122 A 2.20 Stockholm: National Museum A 2.21 Musée de l’Œuvre Notre-Dame A 2.23 as for A 2.8 A 2.26 – 29 as for A 2.8

Designing facade openings A 3.1 Christian Schittich, Munich A 3.2 thomasmayerarchive.de A 3.3 Thomas Dix / [email protected] A 3.4 Matthias Frey A 3.5 Jörg Dietrich (panoramastreetline.de) A 3.6 Helmut Kuzina, Wismar A 3.9 David Zidlicky A 3.10 eliinbar.files.wordpress.com/2012/09/ venturi13349714604561.png A 3.11 Siegfried Schrotz, Reilingen A 3.12 Zairon / Commons Wikimedia A 3.14 Mahargh Shah / Commons Wikimedia A 3.15 from Domus 548 /7-1975 A 3.17 Stefan Müller A 3.18 Gerd Gassmann, Karlsruhe A 3.19 Hiroyuki Hirai A 3.20 from Ronner, Heinz: Öffnungen. Baukonstruktion im Kontext des architektonischen Entwerfens. Basel / Boston / Berlin 1991, p. 89 A 3.21 © FLC /VG Bild-Kunst, Bonn 2009 A 3.23 Stefan Cremers, Karlsruhe A 3.24 Realities:united – Studio for art and architecture (Berlin) A 3.25 Jan Cremers, Munich A 3.26 Stefan Cremers, Karlsruhe A 3.27 Marco Introini, 2011 © FAI – Fondo Ambiente Italiano Windows and doors in art and culture A 4.1 from Dürer, Albrecht: Underweysung der Messung mit dem Zirckel und Richtscheyt in Linien, Ebnen und gantzen Corporen. Nurnberg 1538 A 4.2 Courtesy of Tim Long – Frank Lloyd Wright Preservation Trust A 4.3 Photo: Katherine S. Dreier Bequest © Artist Right Society (ARS), New York /ADAGP, Paris / Estate of Marcel Duchamp A 4.4 Sabine Hornig and VG Bild-Kunst, Bonn 2015 A 4.5 © Museo Thyssen-Bornemisza, Madrid /Scala, Florence A 4.6 Courtesy of Diller Scofidio + Renfro A 4.7 TM, ® & Copyright © 2013 by Paramount Pictures. All rights reserved. A 4.8 Friends of American Art Collection, 1942.51, The Art Institute of Chicago A 4.9 from: Gion A. Caminada: Vom Nutzen der Architektur. Zurich 2003 A 4.10 bpk / Kunstsammlungen Chemnitz / May Voigt © The Munch Museum / The Munch Ellington Group, VG Bild Kunst A 4.11 bpk / Nationalgalerie, SMB /Jörg P. Anders Solution principles for adjustable openings A 5.1 Peter Bonfig, Munich A 5.2 Roto Dach- und Solartechnologie GmbH A 5.5 Bonfig, Peter: Wirkungsmöglichkeiten von beweglichen Fassadenteilen aus nachwachsenden Rohstoffen. Dissertation TUM University 2007, p. 21 A 5.7 Bayerische Staatsgemäldesammlungen, Munich. Photo: Joachim Blauel, Artothek A 5.10 from Herzog, Thomas; Krippner, Roland; Lang, Werner: Facade Construction Manual. Basel 2004, p. 41 A 5.13, 14 Peter Bonfig, Munich A 5.15 Paul Sindram A 5.17 Peter Bonfig, Munich A 5.18 – 20 as for A 5.5, p. 26 – 28 A 5.21 from: as for A 5.10, p. 44 and Westenberger, Daniel: Untersuchungen zu Vertikalschiebefenstern als Komponenten im Bereich von Fassadenöffnungen. Dissertation at the Department of Building Technology at TUM University 2005, p. 25 – 27 A 5.22 as for A 5.5, p. 38 A 5.23 Knippers Helbig, Stuttgart A 5.24 ICD University of Stuttgart A 5.25 as for A 5.5, p. 37 A 5.26 – 28 Peter Bonfig, Munich A 5.29 Jörg Hohberg, Munich A 5.30 as for A 5.5, p. 43

Part B B

Christian Schittich, Munich

Requirements and protective functions – building physics fundamentals B 1.1 Stefan Cremers, Karlsruhe B 1.2 – 6 Jan Cremers, Munich B 1.7, 8 Jan Cremers, Munich (various data sources) B 1.9 Markus Binder, Stuttgart B 1.10 Interpane Beratungscenter (IBC), Plattling B 1.11 Markus Binder, Stuttgart B 1.12 Drawn from Schittich, Christian et al.: Glasbau Atlas. Munich, 2006 B 1.13 Jan Cremers, Munich, drawing on Wagner, Andreas et al.: Energieeffiziente Fenster und Verglasungen. Stuttgart 2013, p. 26 B 1.14 as for B 1.13, p. 312 B 1.15 from DIN EN ISO 6946, Para. 5.2, Table 1 B 1.16 Günther Hanke (www.energieberateroberbayern.de) B 1.17 Jan Cremers, Munich B 1.18 from Hegger, Manfred et al.: Energie Atlas. Munich, 2007, p. 58f. (B1.62 and B1.63) B 1.19, 20 Markus Binder, Stuttgart B 1.21 from DIN EN ISO 7730, Image 4 B 1.22 Interpane Glas Industrie AG, Lauenförde B 1.23 Markus Binder, calculations acc. to Bruno Keller, Pinpoint Bauphysik B 1.24 Markus Binder, Stuttgart B 1.25 from Baus, Ursula; Siegele, Klaus: Öffnungen. Vom Entwurf bis zur Ausführung. Munich, 2006, p. 24 B 1.26 from Willems, Wolfgang M.; Dinter, Simone; Schild, Kai: Vieweg Handbuch Bauphysik Teil 1: Wärme- und Feuchteschutz, Behaglichkeit, Lüftung. Wiesbaden 2006 B 1.27 Jan Cremers, Munich (various data sources) B 1.28 from Jehl, Wolfgang: Montageleitfaden, incl. Montagetaschenbuch; Leitfaden zur Planung und Ausführung der Montage von Fenstern und Haustüren für Neubau und Renovierung. Publisher: RAL-Gütegemeinschaft Fenster und Haustüren e. V. Compiled by the RALGütegemeinschaft Fenster und Haustüren e. V. and ift Rosenheim, 3-2014, p. 53f. B 1.29, 30 as for B 1.28, p. 80 B 1.31 from DIN EN 12 208 B 1.32 as for B 1.14, p. 280 B 1.33 Markus Binder, according to figures from DIN 1946-6 B 1.34 as for B 1.13, p. 30 B 1.35 from Pech, Anton (ed.): Fenster, Band 11 aus Baukonstruktionen. Vienna / New York 2005, Figs. 110-3.05 B 1.36 ift Rosenheim B 1.37 from DIN EN 12 207 B 1.38 as for B 1.28, p. 58 B 1.39 Jan Cremers, Munich B 1.40 from Härterich, Manfred et al.: Installationsund Heizungstechnik. Haan-Gruiten 2011, p. 637 B 1.41 as for B 1.28, p. 63 B 1.42 Markus Binder, HFT Stuttgart B 1.43 from DIN 4109:1989, Tables 8, 9, 10 B 1.44 from VDI guideline 2719 B 1.45 as for B 1.13, p. 36 B 1.46 as for B 1.28, p. 89 B 1.47 as for B 1.28, Table 4.11, p. 85 B 1.48, 49 as for B 1.28, p. 86 B 1.50 from www.finstral.de, Optimale Schalldaemmung.pdf (page 5) B 1.51 from DIN 4109 Supplementary Sheet A1 B 1.52 from DIN EN 13 501-1:2002-6 B 1.55 ift Rosenheim, from EN 13 501-2 and EN 1364-1 B 1.56 Jan Cremers, Munich B 1.57– 59 ift Rosenheim B 1.60 as for B 1.28, Fig. 5.18, p. 133 B 1.61 Jan Cremers, Munich

283

B 1.62 B 1.63

as for B 1.14, p. 211 from DIN 18 008-2 or formerly Technical rules for the use of linear-supported glazing (Technische Regeln für die Verwendung von linienförmig gelagerten Verglasungen – TRLV) B 1.64 Jan Cremers and ift Rosenheim, drawing on materials from standards (specified in Fig.) and as for B 1.14, p. 49 B 1.65 ift Rosenheim B 1.66 left from VELFAC, Horsens B 1.66 right Eva Schönbrunner, Munich B 1.67, 68 Richtlinie zur Beurteilung der visuellen Qualität von Glas für das Bauwesen (Guideline for assessing the visual quality of glass for construction) 5/2009 B 1.69 from DIN EN 12 519:2004 B 1.70, 71 from DIN 18 202 B 1.72 Jan Cremers, Munich (various data sources) B 1.73 as for B 1.28, p. 144 B 1.74 Bundesministerium für Verkehr, Bau und Stadtentwicklung (pub.): Leitfaden Nachhaltiges Bauen. Berlin 2001, Anlage 6 B 1.75 from ISO 15 686 Materials, components, types of construction B 2.1 Fiberline Composites A /S, Middelfart B 2.2 Jan Cremers, Munich (various data sources) B 2.3 as for A 5.10, p. 185 B 2.4 Markus Binder, Stuttgart B 2.5, 6 from Neroth, Günter; Vollenschaar, Dieter: Wendehorst Baustoffkunde: Grundlagen – Baustoffe – Oberflächenschutz. Wiesbaden, 2011 B 2.7, 8 from Schittich, Christian et al.: Glasbau Atlas. Munich, 2006, p. 68 B 2.9 Glas Trösch Beratungs-GmbH, Ulm-Donautal B 2.10 from DIN EN 1096-2 B 2.11 Interpane Glas Industrie AG, Lauenförde B 2.12 according to information provided by the Interpane Beratungs-center (IBC), Plattling B 2.13 based on commons.wikimedia.org/wiki/ File:Image-Metal-reflectance.png B 2.14 Flachglas Wernberg GmbH, WernbergKöblitz B 2.15 Jan Cremers, Munich B 2.16 based on de.wikipedia.org/wiki/MehrscheibenIsolierglas#/media/File:Isolierglas.svg B 2.17 Jan Cremers, Munich, based on information provided by the manufacturer B 2.18 Uniglas GmbH & Co. KG, Montabaur B 2.19 from Glas Trösch Beratungs-GmbH, Ulm-Donautal B 2.20 Jan Cremers, Munich B 2.21 Jan Cremers, Munich, based on DIN EN 14 351-1 and DIN 4108-4 B 2.22 Jan Cremers, Munich B 2.23, 24 based on information provided by the Interpane company, Lauenförde B 2.25 a Jan Cremers, Munich B 2.25 b, c ZAE-Bayern e. V. B 2.26 a, b based on an original by Steffen Jäger, Braunschweig B 2.27 Jan Cremers, based on information provided by various manufacturers: SmartGlass, Flachglas Wernberg, Interpane and Econtrol B 2.28 from EControl-Glas GmbH & Co. KG, Plauen B 2.29 Jan Cremers, information provided by EControl-Glas GmbH & Co. KG, Plauen B 2.30 EControl-Glas GmbH & Co. KG, Plauen B 2.31 Marc Detiffe B 2.32 – 34 Jan Cremers, Munich B 2.35 I-S-T AG, Prutting B 2.36 a Gaston Wicky, Zurich B 2.36 b, c according to information provided by GlassX AG, Zurich B 2.37 as for B 1.14, S. 33 (with additions by Jan Cremers) B 2.38 from Hochberg, Anette; Hafke, Jan-Hendrik;

284

Raab, Joachim: Öffnen und Schließen – Fenster, Türen, Tore, Loggien, Filter. ScaleReihe. Basel / Boston / Berlin 2009, p. 54 B 2.39 as for B 2.38, p. 45 B 2.40 as for B 1.35, Figs. 110.2-04 B 2.41 Internorm International GmbH, Traun B 2.42 Jan Cremers, Munich B 2.43 as for B 1.14, p. 33 B 2.44 Jan Cremers, Munich, pictogram from the ift Rosenheim (apart from steel) B 2.45 Jan Cremers, Munich (various data sources) B 2.46 Huber & Sohn, Bachmehring B 2.47 as for B 1.14, p. 67 B 2.48 from DIN 68 121-1 B 2.49 as for B 1.25, p. 27 B 2.50 Jansen AG, Oberriet B 2.51 Otto Fuchs KG, Meinerzhagen B 2.52 – 54 Schüco International KG, Bielefeld B 2.55 Schneider Fensterbau GmbH B 2.56 Kneer GmbH, Westerheim B 2.57 Rauh SR Fensterbau GmbH B 2.58 Fiberline Composites A /S, Middelfart B 2.59 as for B 1.14, p. 81 B 2.60 Jan Cremers, Munich, based on DIERKSBaukonstruktion Fig. I.13.2 B 2.61 as for B 1.14, p. 318 – 320, from DIN 18 545 and information provided by the ift Rosenheim B 2.62, 63 as for B 1.14, p. 77 B 2.64 as for B 1.14, p. 74 B 2.65 as for B 1.14, p. 75 B 2.66 Christian Walch – walchfenster04 B 2.67 from www.g-u.com B 2.68 as for B 1.14, p. 56 B 2.69 Bloomframe B. V. B 2.70 Christian Schittich, Munich B 2.71 from Schumacher, Michael; Schaeffer, Oliver; Vogt, Michael-Marcus: move, Architektur in Bewegung – Dynamische Komponenten und Bauteile. Basel 2010, p. 66f., p. 69 B 2.72 Aumüller Aumatic GmbH, Thierhaupten (D) B 2.73 from VELUX Deutschland GmbH, Hamburg B 2.74 VELUX Deutschland GmbH, Hamburg B 2.75 Roto Dach- und Solartechnologie GmbH, Bad Mergentheim B 2.76 –79 VELUX Deutschland GmbH, Hamburg B 2.80 from VELUX Deutschland GmbH, Hamburg B 2.81 Glas Trösch Beratungs-GmbH, Ulm-Donautal / Fiberline Composites A /S, Middelfart B 2.82 from DIN 4102-13 B 2.83 Jan Cremers, Munich B 2.84 nach DIN EN 1364-1 B 2.85 VELUX Deutschland GmbH, Hamburg Building connection and structural context B 3.1 Eva Schönbrunner, Munich B 3.2 Jan Cremers, Munich, from Ronner, Heinz: Öffnungen. Baukonstruktion im Kontext des architektonischen Entwerfens. Basel / Boston / Berlin 1991, p. 93 B 3.3 as for B 1.28, p. 12 B 3.4 Jan Cremers, Munich, as for B 2.38, p. 40 B 3.5 as for B 1.28, p. 99 B 3.6 as for B 1.28, p. 103 and 105 B 3.7 as for B 1.14, p. 83 B 3.8, 9 as for B 1.28, p. 100, 101 B 3.10, 11 Jan Cremers, Munich B 3.12 Finstral AG, Unterinn / Ritten B 3.13 as for B 1.28, p. 64 B 3.14 as for B 1.28, p. 129 B 3.15 as for B 1.28, p. 126f., fig. B 3.15 e with additions by Jan Cremers B 3.16 ift Rosenheim B 3.17 as for B 1.13, p. 99 B 3.18 as for B 1.14, p. 42 B 3.19 from Technische Systeminfo 6 – Wärmedämmverbundsysteme zum Thema Brandschutz, Fachverband Wärmedämm-Verbundsysteme e. V., Baden-Baden B 3.20 as for B 1.28, p. 149 B 3.21 ift Rosenheim B 3.22 as for B 1.28, p. 128

B 3.23 B 3.24 B 3.25 B 3.26, 27 B 3.28 B 3.29 b B 3.29 B 3.30, 31 B 3.32 B 3.33 B 3.34

as for B 1.28, p. 129 as for B 1.28, p. 135 as for B 1.28, p. 137 as for B 1.28, p. 138 as for B 1.28, p. 142 Jan Cremers, Munich as for B 1.28, p. 143 as for B 1.28, p. 140 as for B 1.14, p. 91 as for B 1.28, p. 148 based on diagrams from www.umweltschutzbw.de and www.abdichten.de B 3.35 – 44 as for B 1.28, p. 153 –163 B 3.45 as for B 1.28, p. 21 B 3.46 ift Rosenheim B 3.47 as for B 1.28, p. 50 B 3.48 Philipp Walker B 3.49a from Clauss Markisen, Architektenmappe_ 2012_01.pdf, p. 373 B 3.49b as for A 5.10, p. 284 B 3.50 from Otto Lueger, Lexikon der gesamten Technik (1904) B 3.51 Stefan Cremers, Karlsruhe B 3.52 Christian Schittich, Munich B 3.53 from Bundesinnungsverband des Glaserhandwerks, Bundesverband Holz und Kunststoff, Verband der Fenster- und Fassadenhersteller e. V., RAL-Gütegemeinschaft Fenster und Haustüren e. V.: Leitfaden zur Montage von Fenstern und Haustüren mit Anwendungsbeispielen. Compiled by the ift Rosenheim. Düsseldorf 2010, p. 193 and 212 B 3.54 from Clauss Markisen, Architektenmappe_ 2012_01.pdf, p. 45 B 3.55 from Futagawa, Yukio (ed.); Bauchet, Bermard; Vellay, Marc: Maison de Verre, Pierre Chareau. Tokyo 1988, p. 152 B 3.56 Florian Holzherr, Munich B 3.57 Archimage, Meike Hansen B 3.58 Jan Cremers, Munich B 3.59 Rasmus Norlander, Zurich B 3.60 Schüco International KG, Bielefeld B 3.61 as for B 1.14, p. 122 B 3.62 as for B 1.14, p. 123 B 3.63 as for B 1.14, p. 126 B 3.64 from Technical Rules for Workplaces (Technische Regeln für Arbeitsstätten – ASR) A 2.3 B 3.65 as for B 1.14, p. 125 B 3.66 as for B 1.28, p. 34 B 3.67 as for B 1.28, p. 35 B 3.68 as for B 1.28, p. 39 B 3.69 as for B 1.28, p. 36f. B 3.70 Messe Düsseldorf B 3.71 as for B 1.14, p. 221f. B 3.72 Jan Cremers, Munich B 3.73 Werner Lang, Munich B 3.74 a Nansi Palla, Stuttgart B 3.75 b from Schüco International KG, Bielefeld B 3.75 Jan Bitter, Berlin B 3.76 a Burckhardt+Partner AG /Foto Daniel Spehr, Basel B 3.76 b Frank Kaltenbach, Munich Working with historic windows in existing buildings and architectural monuments B 4.1– 3 as for A 2.8 B 4.5 –10 as for A 2.8 B 4.11 Achim Bednorz, Cologne B 4.12 – 24 as for A 2.8 B 4.25 from Belhoste /Leproux, 1997, p. 18 B 4.27– 33 as for A 2.8 B 4.34 from Sammlung Göschen Fenster, Türen, Tore. p. 77 B 4.35 – 28 as for A 2.8 B 4.39 as for B 4.34 B 4.40, 41 as for A 2.8 B 4.42 Christian Schittich, Munich B 4.43 – 45 as for A 2.8 B 4.48 as for A 2.8 B 4.50 –71 as for A 2.8

Part C C

Frank Kaltenbach, Munich

Passive solar energy use C 1.1 from: Daniels, Klaus: Low Tech – Light Tech – High Tech. Bauen in der Informationsgesellschaft. Basel / Berlin / Boston 1998, p. 46, 59 C 1.2 from: Gut, Paul; Ackerknecht, Dieter: Climate Responsive Building. St. Gallen 1993, p. 27 C 1.3, 4 Federal Ministry for Regional Planning Building and Urban Development (Ed.): Guide Passive Nutzung der Sonnenenergie. Booklet 04.097. 1984 C 1.5 from DIN 4710 C 1.6, 7 Federal Ministry for Regional Planning Building and Urban Development (Ed.): Guide Passive Nutzung der Sonnenenergie. Booklet 04.097. 1984 C 1.8, 9 as for A 5.10, p. 20 and 25 C 1.10 Markus Binder, Stuttgart C 1.11, 12 Jan Cremers, Munich C 1.13 Jan Cremers, Munich, using as for B 1.13, p. 48 C 1.14 as for B 1.14, p. 98 C 1.15 as for B 1.13, p. 24, therein: Roos et al., Solar Energy 69 (2000), p. 15 – 26 C 1.16 from DIN 4108 C 1.17 as for B 2.7, p. 121 C 1.18 Markus Binder, Stuttgart, according to manufacturer data C 1.20 as for B 1.14, p. 101 C 1.21 as for C 1.18 C 1.22 glassdbase.unibas.ch, Prof. Dr P. Oelhafen C 1.23 German Federal Environmental Foundation (DBU) C 1.24 as for A 5.10, p. 261 C 1.25 from: Gut, Ackerknecht. Climate responsive Building. St. Gallen: SKAT 1993 C 1.26 company statements (including I-S-T, DS Plan, Gartner, Infacon) and Hausladen, Gerhard among others: ClimaSkin. Munich 2007, p. 136 C 1.27 Markus Binder, Stuttgart C 1.28 Markus Binder, Stuttgart, calculated according to DIN V 18 599-2. 2011-12 C 1.29, 30 as for B 1.13, p. 111 C 1.31 as for B 1.13, p. 112 C 1.32 Markus Binder, Stuttgart C 1.33 as for B 1.13, p. 114 C 1.34 as for B 1.13, p. 118 C 1.35 – 38 Lukas Blattmann / Daniela Weisbarth, HFT Stuttgart C 1.39 Melanie Monecke / Nicole Schmidt, HFT Stuttgart C 1.40 from: Lahme, Andreas: Beispiele und Vergleiche – Zum einfachen Berechnungsverfahren der Tageslichtautonomie und des Strombedarfs für die künstliche Beleuchtung von Räumen speziell für die frühe Gebäudeplanungsphase. Braunschweig 2002, p. 7 C 1.41, 42 Arne Abromeit, Karlsruhe C 1.43 from: D. Haas-Arndt, Hanover; I. Schädlich, Siegen C 1.44 from: Neufert, Ernst: Design lesson. Wiesbaden 2012, p. 175 C 1.45, 46 from: Sebastian Fiedler, Frankfurt / M., using material from the Institut für Licht und Bautechnik (ILB), Cologne Active solar energy use C 2.1 SSC GmbH C 2.2, 4 Thomas Stark, Constance C 2.5 from: Otto Wulff Bauunternehmung GmbH / schönknecht : kommunikation gmbh C 2.6 Thomas Stark, Constance C 2.7 a Solarbayer GmbH, Pollenfeld-Preith C 2.7 b Viessmann Werke GmbH & Co. KG, Allendorf (Eder) C 2.8, 9 Michael Bender, Darmstadt C 2.10 iStockphoto / Saifudeen Dag C 2.11 Heliatek GmbH, Dresden

C 2.12

http://products.newformenergy.ie/photovoltaic-thermal-pvt.php C 2.14 –16 Thomas Stark, Constance C 2.17 SMA Solar C 2.18 FG+SG fotografia de arquitectura C 2.20 Roto Dach- und Solartechnologie GmbH C 2.21 Jan Cremers, Munich C 2.23 Grégoire Kalt, Paris C 2.24 Reto Miloni, Wettingen

C 4.8, 9 C 4.10 C 4.11 C 4.12

Technical building components in and around windows C 3.1 Stefan Müller-Naumann / Colt International GmbH C 3.2 Markus Binder, Stuttgart C 3.3 from: Renson Ventilation, Waregem: from the brochure: Intelligente natürliche Lüftung für Wohngebäude (as of 05/2013) C 3.4 Markus Binder, Stuttgart C 3.5 as for C 3.3 C 3.6 Markus Binder, Stuttgart, according to data from HS-Luftfilter GmbH, Kiel: Brochure: Grundlagen der Filtertechnik (as of 05/2012) C 3.7 Markus Binder, Stuttgart, calculated based on product documents from Innoperform GmbH, Preititz; Aereco GmbH, HofheimWallau; Renson Ventilation, Waregem C 3.8 from: Gretsch Unitas GmbH, D – Ditzingen: Brochure: Bedarfsgeführte Wohnungslüftung – Optimale Raumluftqualität und Energieeffizienz (as of 04/2013) C 3.9 Aereco GmbH, Hofheim-Wallau C 3.10 Renson Ventilation, Waregem C 3.11 from: HAUTAU GmbH, Helpsen: Product documents “Fensterlüfter Ventra” C 3.12 LUNOS Lüftungstechnik GmbH für Raumluftsysteme, Berlin C 3.13 XtravaganT / Fotolia / Peer Neumann C 3.14 –18 Markus Binder, Stuttgart C 3.19 from: Lüdemann, Bruno (Imtech Deutschland GmbH & Co. KG, Hamburg): Kühlen ohne Kältemaschine, PCM-Techniken für die Raumkühlung, session notes. October 2008 C 3.20 David Matthiessen, Stuttgart C 3.21 Markus Binder, Stuttgart C 3.22 Profine / Newspress.de C 3.23 WindowMaster, Vedbæk C 3.24 RELAG AG für Luftschleieranlagen, Illnau C 3.25 Teddington, from: http://www.teddington.de/ index.php/technik/einbauarten C 3.26 from: Züricher Energieberatung/Swiss Federal Office of Energy (Ed.): Data sheet: Gebäudeeingänge mit grossem Publikumsverkehr, 1998 C 3.27 from: Pistohl: Handbuch der Gebäudetechnik, Volume 2, p. H186. Cologne 2009 from: esco Metallbausysteme GmbH, DitzinC 3.28 gen, from: Schulz, Harald: Die “Evolution der beheizten Fassade”, Facade 1/2005 C 3.29 Kampmann GmbH, Lingen (Ems) from: Pohl, Wilfried et al./ Federal Ministry C 3.30 for Transport, Innovation and Technology (Ed.): LichtAusFassade. Optimierte Tagesund Kunstlichtversorgung über Fassaden – Beurteilung der Energiebilanz und der visuellen Qualität. Berichte aus Energie- und Umweltforschung 26/2012. Aldrans, Dec. 2012 C 3.31 from: Köster Lichtplanung, from http:// www.koester-lichtplanung.de/pages_gb/ projekts_01.html C 3.32 Oliver Schuster, Stuttgart C 3.33, 34 Schüco International KG, Bielefeld

Part D

C 4.13

D

Joost Hartwig, Darmstadt from Mötzl, Hildegund. 2007 Greiner Extrusion GmbH, Nussbach from: Martens, Hans: Recyclingtechnik. Fachbuch für Lehre und Praxis. Heidelberg 2011, p. 177 Joost Hartwig, Darmstadt, based on REWINDO GmbH 2012

Tim Crocker, London

p. 220, 221 Nick Kane, Kingston p. 222, 223 Florian Holzherr, Munich p. 224 – 226 Ruedi Walti, Basel p. 227 Michael Heinrich, Munich p. 228 top Hélène Binet, London p. 228 bottom Christian Schittich, Munich p. 229 Hélène Binet, London p. 230 Ward Snijders, Naarden / MHB p. 231 Brenne Architekten p. 232, 233 Ward Snijders, Naarden / MHB p. 234, 235 Werner Huthmacher, Berlin p. 236 Marius Waagaard p. 237 Gerhard Hagen, Bamberg p. 238, 239 Brigida González, Stuttgart p. 240, 241 top Jochen Stüber, Hamburg p. 242, 243 Pasi Aalto, Trondheim p. 244, 245 Ali Moshiri, Zierenberg p. 246 – 247 top /bottom Adolf Bereuter, Dornbirn p. 247 centre Andreas Gabriel, Munich p. 248, 249 Pedro Pegenaute, Pamplona p. 250 Bruno Klomfar, Vienna p. 251 top Norman Müller, Ingolstadt p. 251 bottom Bruno Klomfar, Vienna p. 252, 253 Iwan Baan, Amsterdam p. 254, 255 Eduard Hueber, Ines Leong, New York p. 256, 257 Holzmanufaktur Rottweil, Hermann Klos p. 258, 259 Roger Frei, Zurich p. 260 ift Rosenheim p. 261 top Patrick Bingham-Hall, Sydney p. 261 bottom Tim Griffith, Melbourne p. 262, 263 archive Olgiati p. 264, 265 Didier Jordan, Geneva p. 268, 269 Hiroshi Ueda, Kanagawa p. 272, 273 Bernd Perlbach, Preetz p. 274, 275 Tim Crocker, London p. 276, 277 Velux / Stamers Kontor. Copenhagen

Life-cycle assessments for windows and exterior doors C 4.1 Christian Schittich, Munich C 4.2 from DIN EN ISO 14 040 C 4.3 from DIN EN 15 804 C 4.4 www.shannonrankin.com, www.justinrichel.com C 4.5 based on EPDs from ift Rosenheim and IBU C 4.6 from ARCHmatic (2013) C 4.7 Bundesverband ProHolzfenster (http://www.proholzfenster.de/43.html)

285

Index 13° isotherm ∫ 125 3-layer model ∫ 121 A absorption ∫ 172 accordion doors ∫ 142 Acidification potential ∫ 210 active technology ∫ 42 actuators ∫ 42, 114 adjustable openings ∫ 36 Air conditioning ∫ 198, 203 Air curtain systems ∫ 140, 203 air density /airtightness ∫ 61, 138 Air permeability ∫ 61, 75 Air vents, active /passive ∫ 199, 201 airborne sound ∫ 66 airtight layer ∫ 122 Alarm glass ∫ 93 aluminium windows ∫ 105, 158, 213 angle of incidence ∫ 184 Anisotropy ∫ 80 Annealed glass ∫ 87, 88 Anti-reflective coatings ∫ 89 anti-glare screen /glare protection ∫ 39, 176, 187 application windows ∫ 128 approvals in individual cases ∫ 72 artificial light / lighting ∫ 170, 176 atmosphere ∫ 172 attachment ∫ 122 Automatic doors ∫ 141 B b factor ∫ 175 ball impact ∫ 78 Bands of diamond panes ∫ 17 Barrier-free openings ∫ 78, 143 base blocks ∫ 124 bending and folding mechanisms ∫ 44 Bible windows ∫ 18 Bionics ∫ 44 blind frame profile ∫ 99 Blind frame window ∫ 18, 124 Block frame window ∫ 124 Blocking ∫ 108 blower door test ∫ 61, 64 Blunt rebate ∫ 124 Bonded edge /edge bonds ∫ 92, 214 Borosilicate glass ∫ 214 box fold ∫ 158 Box-type window ∫ 13, 100, 149, 164 Braun windows ∫ 151 building automation controls ∫ 10 Building connection ∫ 120 building materials classes ∫ 70 building operations ∫ 212 building physics fundamentals ∫ 50 bullseye panes ∫ 14, 17, 19 burglar resistance classes ∫ 76 Burglary prevention ∫ 76 C Carousel doors ∫ 141 casement ∫ 143 casement frame profile ∫ 100 Casement window ∫ 13, 100, 149, 164 Casings and encased windows ∫ 100, 126 cast glass ∫ 18, 87 Cast-iron windows ∫ 158 Cathode sputtering (soft coating) ∫ 89 CE labelling ∫ 72, 84 Chemically strengthened glass ∫ 88 child-proofing ∫ 79 clamp rebate ∫ 99 climate loads ∫ 73 Closed-cavity facades (CCF) ∫ 144 coatings ∫ 89

286

Coefficient of thermal expansion ∫ 83 Cold air downdraughts ∫ 58 cold facades ∫ 144 Cold-warm facade ∫ 144 Colour rendering ∫ 79, 177 colour rendering index ∫ 80 Combinations of materials ∫ 98 comfort criteria ∫ 57 components ∫ 86, 118 Composite frames / hybrids ∫ 107 composite leaf ∫ 163 Composite window ∫ 100, 150, 158, 164 Compound Parabolic Concentrators (CPC) ∫ 44, 47 compression capacity ∫ 133 condensation ∫ 59, 152, 164 conditions ∫ 170 Connection between glass and frame ∫ 108 Connection joints ∫ 120, 130 Construction joints ∫ 63 Constant ventilation ∫ 37 Construction principles ∫ 149 construction products ∫ 212 Construction Products Regulation ∫ 83 control function ∫ 38 convection ∫ 41 Convectors / Convector heaters ∫ 205 cooling energy requirements ∫ 170 cooling load calculations ∫ 175 Coupled window ∫ 100, 150, 158, 164 coupling joints ∫ 130 Cradle-to-grave assessment ∫ 208 Criteria used in evaluating and assessing glazing ∫ 80 Cross ventilation ∫ 63 crossbar windows ∫ 17 crown glass pane ∫ 19 cultural and developmental history of the window ∫ 12 curtain wall ∫ 120 cylinder blowing process ∫ 19 D Data sources on life-cycle assessment data ∫ 212 daylight ∫ 170, 176, 186 Daylight autonomy ∫ 186, 187 Decorative facades ∫ 27 Deformation ∫ 81 desiccants ∫ 91 design of facade openings ∫ 24 Designer coatings ∫ 90 dew point temperature ∫ 64 diamond-pane glazing ∫ 16, 17, 20 diamond-shaped panes ∫ 16, 17 differential pressure test ∫ 61, 64 Dimensions and tolerances ∫ 80 disposal ∫ 216 Double windows / Double-hung window ∫ 149, 100 double-glazed facade ∫ 150 double-skin facades ∫ 149 double-shell glazing ∫ 144 Draughts ∫ 37 drawn glass ∫ 87 drip edge ∫ 137 dry glazing ∫ 108 Durability ∫ 82 dynamic selectivity ∫ 94 E edge bonds / Bonded edge ∫ 92, 214 Edgings ∫ 28 Electrochromic glazing ∫ 95 Electromagnetic damping ∫ 73 electromagnetic radiation ∫ 172 element facades ∫ 144 Elements, moveable ∫ 180 emissivity ∫ 52, 172, 176 End of life: recycling ∫ 215

energy balance ∫ 182 energy improvements ∫ 148 environmental effects / impact ∫ 210, 212, 217 Environmental labelling ∫ 210 Environmental Product Declaration EPD) ∫ 208, 212 escape and panic locks ∫ 142 EU’s revised construction products regulation (EU-Bauproduktenverordnung (BauPVO) ∫ 208 Euro rebate / Euro groove ∫ 113 Eutrophication Potential (EP) ∫ 210 exchange of air ∫ 37 Exhaust air ∫ 39 Exhaust ventilator ∫ 200 Extension capacity ∫ 133 Exterior doors ∫ 139 Exterior rebate ∫ 125 F facade order ∫ 24 Facade types ∫ 144 Facade-integrated ventilation ∫ 203 Facades, heated ∫ 205 false facades ∫ 27 Fastening systems and elements ∫ 128 Federal state building regulations (Landesbauordnungen (LBO)) ∫ 70 fenêtre en longueur ∫ 29 Fillings ∫ 214 finger protection ∫ 79 Fire barriers, fire blocks ∫ 128 Fire behaviour ∫ 70 Fire protection ∫ 70 Fire resistance classes ∫ 71 Fire-resistant glazing ∫ 72, 116 fittings ∫ 111 Fixed glazing ∫ 153 Flat glass ∫ 87 Float glass ∫ 87 Flush box-type window ∫ 150 Folding doors ∫ 142 folding shutters ∫ 15 folding shutters hung from above ∫ 17 folding sliding shutters ∫ 45 Folding windows ∫ 157 forest glass ∫ 17 Frame materials ∫ 101, 213 frame profiles ∫ 99, 101 frames of reference ∫ 30 front shutters ∫ 138 functional coatings ∫ 174, 177, 214 functional glazing ∫ 177 Functional joints ∫ 63 Functional zone ∫ 122 G Gas filling in the space between panes ∫ 92 German Construction Contract Procedures (VOB) ∫ 136 German Energy Saving Ordinance (Energieeinsparverordnung (EnEV)) ∫ 55, 56, 61, 63, 65, 66, 215 Glaser method ∫ 59 Glass production ∫ 18 Glass sealing ∫ 108 Glazing ∫ 73, 96, 214 Glazing rebates ∫ 108 Glazing tape ∫ 109 global solar radiation ∫ 170 Global warming potential ∫ 209 Greenhouse effect ∫ 170, 173 GRP frames ∫ 107 gueule de loup ∫ 99, 158 H h,x diagram or Mollier diagram ∫ 64 heads /cross bar ∫ 99, 100 Heat conductivity ∫ 53 Heat-insulating glazing ∫ 178

Heat recovery ∫ 201 heat transfer coefficient ∫ 53, 54 Heat transport ∫ 51 Heated facades ∫ 205 heating energy requirements ∫ 182 hinge windows ∫ 153 historical windows ∫ 148 Historical windows ∫ 161 historically protected windows ∫ 148 holographic-optical elements (HOE) ∫ 44, 89 honeycomb-shaped panes ∫ 18, 20 Horizontal glazing ∫ 76 Horizontal loading capacity ∫ 75 Horizontal slide windows ∫ 154 Horizontal wind loads ∫ 74 Humidity protection ∫ 59 Hybrid ventilation ∫101 I Illuminance ∫ 176 Impact categories of a life-cycle assessment ∫ 209 incidence of radiation energy ∫ 39 incident daylight ∫ 39 incoming air ∫ 37, 62, 201, 203 indicator function ∫ 57 Inflexible systems ∫ 170 Inner rebate ∫ 124 inner windowsills ∫ 137 Insect protection ∫ 78, 97 insertion frames ∫ 125 Installation level ∫ 61 installation site ∫ 75 installation situation ∫ 215 Insulating glass windows ∫ 152, 164 Insulating glazing ∫ 94, 153, 177, 216 insulation level ∫ 126 Intensive ventilation ∫ 62 interior air quality ∫ 37 Intermittent ventilation ∫ 37/ International Commission on Illumination (CIE) ∫ 186 IR radiation ∫ 172 Isotherm diagram ∫ 55 J jambs /pillars / mullions ∫ 99 joining techniques ∫ 99 Joint construction ∫ 131 Joint insulation ∫ 128 joint permeability ∫ 61 joint seal ∫ 133 joint sealants ∫ 133 joints ∫ 59, 60 K Kinematics

∫ 41, 42

L Laminated glass ∫ 89 Laminated safety glass ∫ 88 lap fold ∫ 156 large openings /windows ∫ 154, 155 layers ∫ 40, 46, 120 leaf fitted with special hinges ∫ 163 Life-cycle assessments (LCA) ∫ 208, 214 light deflection ∫ 38, 172, 189 light diffusion ∫ 39, 189 Lighting ∫ 79, 206 lime-soda glass ∫ 214 Linear expansion ∫ 82 linear heat transfer coefficient (Psi value) ∫ 54 lintel box ∫ 138 lintels ∫ 120 load groups ∫ 110 load transfer ∫ 122 location ∫ 171 long-wave thermal radiation ∫ 172 Louvre structures ∫ 45

low-e coatings ∫ 42, 52, 178 luminance contrasts ∫ 78 Luminous intensity / luminance ∫ 176, 188 M M glass ∫ 178 Maintenance ∫ 215 Maintenance and sustainability ∫ 160 mass-spring-mass principle ∫ 67 materials ∫ 86 Mechanical requirements ∫ 73 media facades ∫ 30 Metal windows ∫ 157, 165 middle-hung leafs ∫ 156 middle-hung windows ∫ 155 minimum air exchange rates ∫ 61 minimum degrees of illuminance ∫ 176 Minimum insulation ∫ 65 Model Building Regulation (Musterbauordnung (MBO)) ∫ 70 Modular skylight ∫ 117 motorised drive unit ∫ 115 mould formation ∫ 64 Moveable elements ∫ 180 movement areas ∫ 78 movement joints ∫ 130 Movement-compensating potential ∫ 81 mullions ∫ 55 mullion-transom facades ∫ 144 multifunctional layers ∫ 179 Multifunction strips ∫ 134 multi-pane insulating glazing units ∫ 53, 91, 153 Multiple windows ∫ 100 N national general test certificate (allgemeines bauaufsichtliches Prüfzeugnis (abP)) ∫ 72 national technical approval (allgemeine bauaufsichtliche Zulassung, (abZ)) ∫ 72 Natural ventilation ∫ 62, 203 need for heating energy ∫ 170 night ventilation ∫ 203 noble or inert gases (argon, krypton and xenon) ∫ 53, 216 Noise level zone ∫ 66 O Old windows and doors ∫ 215 opening ∫ 15 opening element’s position in the reveal ∫ 25 opening elements ∫ 24, 29, 37 ,40 Opening elements (NSHEV) ∫ 115, 116, 117, 118 opening limiters ∫ 79 operating principle ∫ 42 Optical requirements ∫ 80 optimum proportion of opening surfaces ∫ 186 ordering principle ∫ 24 orientation ∫ 171, 182 Original plastic windows in protected buildings ∫ 160 Ornament ∫ 29 Outer rebate ∫ 126 Outer windowsills ∫ 135, 137 Overlapping insulation of frame profiles ∫ 127 Ozone depletion potential ∫ 210 P Panels ∫ 97 Panorama windows ∫ 156 parapet element ∫ 75 parts of openings ∫ 28 passive solar energy use ∫ 170 Perforated surfaces ∫ 45

R Rack and pinion drives ∫ 114 radar reflection damping ∫ 73 Radiation ∫ 44 Radiation asymmetry ∫ 57 Radiation input ∫ 41 range of humidity ∫ 57 raw materials ∫ 212 Rebate clearance ∫ 61 rebate drainage ∫ 108 rebate principle ∫ 99 Rebate types ∫ 124 rebate vents ∫ 199 recessed windows ∫ 27 Recycling quota ∫ 216 Recycling systems ∫ 215 Recycling window components ∫ 215 reflection ∫ 30, 172 reflection capacity ∫ 172 regulation or control ∫ 37 regulation technologies ∫ 42 regulatory process ∫ 42 Rekord windows ∫ 151 relative humidity ∫ 59, 64 relief arches ∫ 120 Resistance to driving rain ∫ 75 Restoration ∫ 149, 161 ribbon facade ∫ 144 ribbon windows ∫ 21, 120, 152, 156 Roller shutter boxes ∫ 138 roof windows ∫ 115 Rotating leaf / pivoting ventilation sashes ∫ 18, 166 Rotating leaf window ∫ 153 Rotating window ∫ 43 Rotation ∫ 43

Sensors ∫ 63, 93, 115, 118, 200, 206 Service life issues / Life-cycle assessments ∫ 83, 208 service potential ∫ 171 shade concept ∫ 186 shading coefficient (FC value) ∫ 176 Shading Coefficient (SC) ∫ 175 Shaft ventilation ∫ 63, 201 Sheet glass ∫ 87 Shell glazing ∫ 152, 164 shells ∫ 40, 46, 120, 144 simulation programmes ∫ 187 Single glazings / Single-glazed windows ∫ 149, 163 Single window ∫ 99 Sink window ∫ 157 Size and layout of openings ∫ 182 skylight dome ∫ 113 Sliding doors ∫ 142 sliding shutters ∫ 17 sliding ventilation sashes ∫ 18 Smart materials ∫ 41 smoke and heat extractors ∫ 70, 116 sol-gel process ∫ 89 solar radiation ∫ 170, 173 solar energy ∫ 170 solar spectrum ∫ 172 solar thermal radiation ∫ 172 sound insulation of joints ∫ 67 Sound proofing / Sound insulation ∫ 40, 66, 69, 126, 200 Soundproof windows ∫ 69, 93 space between panes ∫ 53, 69, 73, 153, 214 spacer systems ∫ 92 spacers ∫ 54, 92 spacers, punctiform ∫ 94 spacing blocks ∫ 124 spatial dimension ∫ 26 special fittings ∫ 114 Special safety glazing ∫ 77 Special windows ∫ 166 spectral range ∫ 172 Spindle drives ∫ 113 stained glass windows ∫ 166 Steel window frames ∫ 104 Stepped insulating glass ∫ 93 stepped-edge rebate ∫ 99 Structural Glazing ∫ 111 structural integrity ∫ 120 structure-borne sound ∫ 66 structures ∫ 25, 40, 46 subframe ∫ 126 Summer heat insulation ∫ 183 Sun-screening glazing ∫ 178 sun’s angle of incidence ∫ 184 sunscreen systems ∫ 39, 176 sunscreens /solar protection ∫ 170, 175, 180, 182 support blocks / bearing blocks ∫ 108, 124 sustainability certification ∫ 82 swing doors ∫ 78

S safety barrier ∫ 75 sash bars ∫ 93, 99, 149 sash locks ∫ 112 Sash windows ∫ 157 scheduling ∫ 143 sealant groups ∫ 110 sealing ∫ 59 Sealing films ∫ 134 Sealing layers ∫ 130 Sealing of structural connection joints ∫ 129 sealing profiles /sealant ∫ 109, 111 Sealing systems ∫ 132 Sealing tapes ∫ 68, 133 Selective systems ∫ 42 Selectivity ∫ 172, 176 Self-cleaning glass ∫ 90

T Technical Building Rule (eingeführte Technische Baubestimmung – ETB) ∫ 72 Temperature factor ∫ 65 temperature of the air in the room ∫ 57 Tempered or toughened glass ∫ 87 Temporary insulation ∫ 38, 58 Thermal bridges ∫ 55, 65 Thermal comfort ∫ 57 Thermal conduction ∫ 51 Thermal convection ∫ 51 thermal radiation ∫ 172 Thermal resistance ∫ 53, 54 thermal separation ∫ 106 Thermograph ∫ 55 Three-edge adhesion ∫ 133 Threshold ∫ 99, 142

Performance profiles ∫ 38 Permanent ventilation ∫ 62 Permeability ∫ 41 Phase-Change-Materials (PCM) ∫ 41, 99, 203 Photochemical ozone creation potential ∫ 210 pivoting shutters ∫ 15 plaster seal strips ∫ 131, 136 Plastic ∫ 107, 159, 213, 216 Plastics and membranes ∫ 96 porte-fenêtre ∫ 28 potential use for solar power ∫ 188 pressure equalisation ∫ 109 Pressure glazing ∫ 111 Primary energy requirement ∫ 210 printing ∫ 90 Profile drainage ∫ 128 Proof of suitability and official approval ∫ 72 proportion of window surface ∫ 183, 187 Proportion systems ∫ 24 Protection for openings ∫ 40 protective functions ∫ 36, 50 Pyrolytic coating ∫ 89

tilt and turn leafs ∫ 166 tilt and turn windows ∫ 43, 153 top-mount roll shutters ∫ 138 total energy requirements ∫ 186 Total energy transmittance coefficient (g value) ∫ 173 Translation ∫ 43 Transmission / transmittance ∫ 30, 41, 170, 172 transmission heat loss ∫ 56 transoms ∫ 99 transparency ∫ 30 triangular joints ∫ 133 turn window ∫ 155 type of opening ∫ 40 type of window ∫ 149 types of construction ∫ 86 types of glass ∫ 214 Types of movement ∫ 26, 43, 74, 179 Types of windows ∫ 99 U users’ satisfaction ∫ 8 Utilisation factor ∫ 183, 188 UV radiation ∫ 172 V Vacuum glazing ∫ 94 vacuum insulation glass ∫ 163 vacuum insulation panels ∫ 98 ventilated curtain facades (VHF) ∫ 144 ventilation ∫ 36, 62, 198, 200, 201, 203 ventilation components ∫ 63, 108 Ventilation concept ∫ 183 ventilation elements ∫ 39 ventilation window ∫ 40 Verification process ∫ 184 Vertical slide windows ∫ 154, 166 views ∫ 79 visible light ∫ 172 W Wagner window ∫ 151 warm edge ∫ 92 Water vapour ∫ 59 Water vapour diffusion in sealing systems ∫ 135 Watertightness / impermeability to driving rain ∫ 59, 60 Weatherproofing ∫ 122 wet-glazed glazing ∫ 108 Wind deflectors ∫ 118 Wind load zones ∫ 75 Wind pressure ∫ 74 window glass (blown) ∫ 13 Window gratings /grilles ∫ 77, 139 Window manufacture ∫ 212 Window materials ∫ 157 window preservation ∫ 148 window putty ∫ 109 window researchers ∫ 16 window unit ∫ 8, 101, 148, 159 windows ∫ 14 Windows in flat roofs ∫ 115 Windows with a smoke extraction function ∫ 118 windows, stained glass ∫ 166 wind-tight ∫ 18 winter windows ∫ 149, 162 Wired glass ∫ 87 wooden shutters ∫ 14, 16 wooden window ∫ 17, 103, 157, 213 Ψ-Wert ∫ 92

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The authors and publishers would like to thank the following sponsor for the assistance with this publication

Schüco International KG Bielefeld (D) www.schueco.com

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Building Openings Construction MANUAL Building openings provide light, ventilation and climate control for rooms. At the same time, they are essential functional and design elements of facades, enabling communication between indoor and outdoor spaces as transparent or translucent structural components. Similar to the entire building envelope, windows and exterior doors must meet exacting standards for materials, construction types and installation conditions, as well as for fire, noise and thermal insulation, energy efficiency, airtightness and building security.

Authors: Jan Cremers, Prof. Dr.-Ing. (Editor) Markus Binder, Prof. Dipl.-Ing. Peter Bonfig, Dr.-Ing. Joost Hartwig, Dipl.-Ing. Wolfgang Jehl, Dipl.-Ing. (FH) Hermann Klos Ingo Leuschner, Dipl.-Ing. (FH) Ulrich Sieberath, Prof. Elke Sohn, Prof. Dr.-Ing. Thomas Stark, Prof. Dr.-Ing.

Institut für internationale Architektur-Dokumentation GmbH & Co. KG, Munich www.detail-online.com

ISBN 978-3-95553-298-7

9 783955 532987