CGA G-2.1-2023 Requirements For The Storage And Handling of Anhydrous Ammonia [7 ed.]

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CGA Compressed Gas Association The Standard For Safety Since 1913

CGA G-2.1—2023 REQUIREMENTS FOR THE STORAGE AND HANDLING OF ANHYDROUS AMMONIA SEVENTH EDITION

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CGA G-2.1—2023

DEDICATION This publication is dedicated in the memory of Patrick “Pat" Hodges, who served as an active participant of the Consensus body that developed this publication and contributed his knowledge and expertise to the ammonia industry for over 40 years.

PLEASE NOTE:

The information contained in this document was obtained from sources believed to be reliable and is based on technical infuimalion and experience currently available from members of the Compressed Gas Association, Inc. and others. However, the Association or its members, jointly or severally, make no guarantee of the results and assume no liability or responsibility in connection with the information or suggestions herein contained. Moreover, it should not be assumed that every acceptable commodity grade, test or safety procedure or method, precaution, equipment or device is contained within, or that abnormal or unusual circumstances may not warrant or suggest further requirements or additional procedure. This document is subject to periodic review, and users are cautioned to obtain the latest edition. The Association invites comments and suggestions for consideration. In connection with such review, any such comments or suggestions will be fully reviewed by the Association after giving the party, upon request, a reasonable oppor¬ tunity to be heard. Proposed changes may be submitted via the Internet at our web site, www.cqanet.com.

This document should not be confused with federal, state, provincial, or municipal specifications or regulations; insurance requirements; or national safety codes. While the Association recommends reference to or use of this document by government agencies and others, this document is purely voluntary and not binding unless adopted by reference in regulations. A listing of all publications, audiovisual programs, safety and technical bulletins, and safety posters is available via the Internet at our website at www.cqanet.com. For more information contact CGA at Phone: 703-788-2700, ext. 799. E-mail: [email protected]. Work Item 08-061 Specialty Gases Committee

NOTE—Technical changes from the previous edition are underlined. NOTE—Appendix A (Normative) is a requirement.

SEVENTH EDITION: 2023 SIXTH EDITION: 2014 FIFTH EDITION: 1990 FOURTH EDITION: 1989 © 2023 The Compressed Gas Association, Inc. All rights reserved. All materials contained in this work are protected by United States and international copyright laws. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical including photocopying, recording, or any information storage and retrieval system without permission in writing from The Compressed Gas Association, Inc. All requests for permission to reproduce material from this work should be directed to The Compressed Gas Association, Inc., 8484 Westpark Drive, Suite 220, McLean, VA 22102. You may not alter or remove any trademark, copyright or other notice from this work.

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CGA G-2.1—2023

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FOREWORD (This Foreword is not a part of American National Standard Requirements for the Storage and Handling of An¬ hydrous Ammonia.) This standard represents the consensus of interested parties concerning minimum safety requirements for the storage, transportation, and handling of anhydrous ammonia. It is intended to serve as a guide for regulatory authorities in writing their own regulations as well as to assist designers of ammonia installations and others having an interest in its requirements such as safety engineers, insurance organizations, and transportation car¬ riers.

The first edition of the K61.1 Standard was published in 1960 and was based on a standard of the Compressed Gas Association, Inc. (CGA) completed in 1950, and submitted to the then American Standards Association for adoption as an American Standard. CGA’s standard was used to assist in developing regulations during the early period of the expanded use of anhydrous ammonia for agricultural purposes. This took place in the late 1940s and early 1950s. In 1953 the Agricultural Ammonia Institute (AAI) published its first standard (M-1) for the storage and handling of agricultural ammonia, which has been revised at frequent intervals to remain current with progress in the agri¬ cultural ammonia industry. When the first American Standard for ammonia was approved in 1960, it made available to those concerned two standards on ammonia from which to choose. Many of the states had already adopted as their regulations, the M-1 standard of the AAI, and from then on the ammonia industry was continually faced with the conflict of having two differing standards available dealing with safety requirements for anhydrous ammonia. The American Standard was revised in 1966 under the sponsorship of CGA and the second edition was made available to interested parties along with revised editions of the similar standards of AAI.

In 1968 the Agricultural Nitrogen Institute (ANI), successor to AAI, requested cosponsorship of the K61 project. CGA supported cosponsorship to achieve the endorsement of a single American National Standard that could be supported jointly by ANI and CGA. The ANI has since merged with the National Plant Food Institute to become The Fertilizer Institute (TFI). As cosecretariats of the K61 Project, CGA and TFI reconciled the differences between the American National Standard K61.1-1966 and the M-1 Standard of The Fertilizer Institute. A revision was prepared and submitted to the K61 Committee for consideration The 1972 and subsequent editions of the K61.1 Standard not only replace the 1966 edition of the American National Standard K61.1, but also supersede the 1966 edition of CGA G-2.1 and the 1968 edition of The Fertilizer Institute M-1 Standard.

Following the 1984 revision of the 1981 edition of the K61.1 Standard, The Fertilizer Institute withdrew from cosponsorship of the K61.1 Standard in 1987, however, TFI elected to continue as an active participant on the K61 Committee. The 1989 edition represented a substantial reorganization and expansion of material contained in prior editions with individual sections devoted to ammonia safety and the use of water in emergencies. A new section regarding tank cars was added in recognition of the importance of the rail transportation mode. Other sections were updated to reflect major changes in the areas of technology and regulatory matters The 1999 edition incorporated the International System of Units (SI) in recognition of the global harmonization movement. The Pressure Relief Device section underwent a major rewrite to provide consistency and account for excessive heat or fire protection. There were also some marking and labeling changes in the regulatory area. The 2014 edition includes updated ammonia exposure information and extensive revision of the safety section to incorporate current regulatory and safety requirements and regulations. This edition also includes revised re¬ quirements for the re-installation of large pressure vessels, for the repair or alteration of pressure vessels, and for dealing with pressure vessels with missing dataplates by incorporating provisions of the National Board

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Inspection Code (NBIC). A new section defines specifications and inspection requirements for pressure transfer hoses used specifically in ammonia service (Information about pressure transfer hose requirements was previ¬ ously addressed in an appendix to the 1999 edition). Another new section defines the requirements for heating devices for containers. The refiiyeialed stoiaye piessute relief valves section also underwent another rewrite to address abnormal operating conditions and fire scenarios with respect to relief requirements.

The 2023 edition includes new definitions, updates to information and valves and gaskets, updated requirements for pressure testing of hoses, and a new section addressing hydrostatic relief valves. This edition also combines information on applicator tanks and nurse tank systems mounted on farm wagons into one section with a separate section addressing ammonia application systems. Suggestions for improvements of this standard will be welcome. They should be sent to the American National Standards Institute, Inc., 25 W. 43id St., New Yoik, NY 10036, or to the Compressed Gas Association, Inc., 8484 Westpark Drive, Suite 220, McLean, VA 22102.

This standard was revised and approved for submittal to ANSI by American National Standards Committee on Safety Requirements for the Storage and Handling of Anhydrous Ammonia. Committee approval of the standard does not necessarily imply that all committee members voted for its approval. At the time it approved this stand¬ ard, the CGA G-2.1 ANS Consensus Body had the following voting members: Organization Represented

Name of Representative

Agribusiness Association of Iowa Airgas Specialty Products Ammonia Safety and Training Institute CF Industries, Inc CHS, Inc

Neal Vaughn Blaine Davis, Chair Kent Anderson David Shea Ken Mueller Mary Biel (Alternate) Chuck Thompson Judd Stretcher Roy Nichols Chuck Cawley John Rebholz George Edwards Tyler Rishel Stanley Thessen David Imhoff (Alternate) Ed Kaiser Terrence Hellman Chad Szymesko Cliff Hayes (Alternate) Danny Starke Billy Pirkle Scott Anderson Tom Vandini Timothy Memmer (Alternate) Cody Reeves MikeWollner Bruce Kasten David Binder

Circle K Manufacturing Company Continental NH3 Products Gas Equipment Company Illinois Department of Agriculture Illinois Fertilizer and Chemical Association Koch Company Services MaXfield, Inc MFA Incorporated

Minnesota Department of Agriculture The National Board of Boiler and Pressure Vessel Inspectors . Nutrien Office of Indiana State Chemist Pirkle Solutions, Inc ProValue Insurance Quality Steel Corporation RegO Products Safety with HELP, LLC Squibb Taylor Inc Tanner Industries, Inc

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Contents

1

Introduction.. Scope 1.1 1.2 General Physical/chemical properties of ammonia 1.3 Ammonia exposure 1.4 Federal, state, and local regulations 1.5 1.6 Hazardous material classification

v

1

.................. 1 1 1 3 4 4 4

2

Definitions

3

Safety. Training 3.1 Normal conditions 3.2 Emergency planning and response coordination 3.3 Permanent storage installations 34 Cargo tanks 35 Leaks in transportation equipment 36 Cylinder and DOT portable tank installations 37 38 Site security

9 9 9 9 10 11 11 11 11

4

Use of water in emergencies Human exposure 4.1 Accidental release 4.2 Fire exposure 4.3 Absorption in water 4.4

12 12 12 12 12

5

Basic rules Equipment and systems 5.1 Requirements for new construction and original test, repair, and alterations of containers 5.2 (including DOT portable tanks), other than refrigerated storage tanks 5.3 Location of containers Markings of nonrefrigerated containers and systems other than DOT containers 5.4 Container appurtenances 5.5 Piping, tubing, fittings, valves, and gaskets 5.6 Hose specification 5.7 Pressure relief valves 5.8 Filling densities 5.9 5 10 Transfer of ammonia 5 11 Liquid level gauging devices 5 12 Painting of containers 5 13 Electrical equipment and wiring 5 14 Heating devices for containers and cylinders

13 13

6

7

Systems using stationary, pier-mounted or skid-mounted, aboveground or underground, nonrefrigerated storage Design pressure and construction of containers 6.1 Container valves and accessories and discharge connections 6.2 Pressure relief valves 6.3 Installation of storage containers 6.4 Reinstallation of containers 6.5 Marking containers 6.6 Protection of container and appurtenances 6.7 Identification for emergency 6.8 Refrigerated storage Design of tanks 7.1 Installation of storage tanks (aboveground) 7.2 Marking refrigerated containers 7.3 Tank valves, accessories, fill pipes, and discharge pipes 7.4

14 16

17 19 20 22 26 29 31 34 34 34 35 35 35 35 36 37 38 38 .39 39 39 39 40 41 41

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7.5 7.6

7.7 7.8 7.9 7.10 8

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Compressed Gas Association, Inc.

Pressure relief valves Protection of containers and appurtenances Reinstallation of containers Refrigeration load and equipment Safety equipment Identification for emergency

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CGA G-2.1—2023

42

.

43 44

44

46 46

Systems mounted on railcar structures (tank cars), other than DOT class 106A, for transportation of ammonia Design and construction 8.1 8.2 Pressure relief valves ...... Marking and placarding 8.3 Tank car loading and unloading locations and operations 8.4

Systems mounted on trucks, serniliailers, and trailers for transportation of ammonia.. Design pressure of containers 9.1 9.2 Container mounting 9.3 Container appurtenances Piping, fittings, and hose 9.4 Pressure relief valves 9.5 Placarding and marking of containers 9.6 Transfer of liquids 9.7 9.8 Trailers and semitrailers Electrical equipment and lighting 9.9 9.10 Protection against collision .. .......................................... 9.11 Brakes 9.12 Portable tanks (including skid tanks) 9.13 Safety equipment

46 46 46 46

47 48 49

49 50 51 51

..

. ..

52 52 52 53 53 53 53 53

10 Systems using DOT portable tanks and cylinders 10.1 Containers and cylinders 10.2 Container and cylinder valves and regulating equipment 10.3 Pressure relief devices

54 54 54 55

11 Applicator tank and nurse tank systems mounted on farm wagons (implements of husbandry) 11.1 Design pressure and construction of containers 11.2 Mounting of containers 11.3 Container appurtenances 11.4 Marking and placarding of containers 11.5 Farm wagons (implements of husbandry)

55 55 55 56 57 58 58 58 59 59

11.6 11.7 11.8 11.9

Transfer hose Safety training and equipment Safety water, decal, and safety data sheet Compatibility

12 Ammonia application systems (implements of husbandry) 12.1 Ammonia application unit 12.2 Metering devices 12.3 Breakaway coupling devices and instructions.. 12.4 Control valves.................................................. 12.5 Ball valves 12.6 Bleed valves 12.7 Withdrawal hose 12.8 Transfer system 12.9 Safety training and equipment 12.10 Compatibility

59 60 60 60 60 60

13 References

60

59 59 59 59 59

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Tables

Table 1—Physical properties of ammonia Table 2—Human physiological responses to various concentrations of ammonia in air Table 3—Regulatory ammonia exposure limits Table 4—Emergency response planning guideline exposure limits Table 5—Minimum separation distances for location of ammonia storage containers Table 6—Maximum permitted filling volumes for nonrefrigerated storage containers Table 7—Ammonia container maximum heating limits

2 3 3 4

17 30 35

Appendices

Appendix A—Minimum required flow rate of pressure relief devices for fire protection (Normative)

63

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1

Introduction

1 1.1

Scope

This standard is intended to apply to the design, construction, repair, alteration, location, installation, maintenance, and operation of anhydrous ammonia systems including refrigerated ammonia storage systems. This standard does not apply to:

•

Ammonia manufacturing plants;

•

Refrigeration systems where ammonia is used solely as a refrigerant. Such systems are covered in ANSI/lnternational Institute of Ammonia Refrigeration (IIAR) 2, American National Standard for Design of Safe Closed-Circuit Ammonia Refrigeration Systems [1]1;

•

Ammonia transportation pipelines; and

• Ammonia barges and tankers. 1.2

General

Where certain provisions of this standard impose undue hardship or where literal adherence to such provisions fails to provide adequate safety in the opinion of the authority having jurisdiction (AHJ), the AHJ may permit deviation from the standard. The values stated in customary units are to be regarded as standard. Metric equivalents where shown in this standard may not be exact, and meet the requirements of ANSI/lnstitute of Electrical and Electronics Engineers (IEEE) SI 10, Amen'can National Standard for Metric Practice procedures in this regard [2],

1.3

Physical/chemical properties of ammonia

1.3.1 Gaseous ammonia liquefies under pressure at ambient temperature. Ammonia is usually shipped or stored as a liquid under pressure. When refrigerated to or less than its normal boiling point of -28 °F (-33.3 °C), it may be shipped or stored as a liquid at or near atmospheric pressure.

1.3.2 Some physical properties of ammonia are listed in Table 1

1.3.3 During liquid releases, ammonia aerosol can form. This aerosol can reach temperatures approaching -100 °F (-73 °C) near the point of release [3],

1.3.4 Ammonia is extremely hard to ignite and is a relatively stable compound. It begins to dissociate into nitrogen and hydrogen at approximately 850 °F (454 °C) at atmospheric pressure. Experiments conducted by a nationally recognized laboratory showed that an ammonia-air mixture in a standard quartz test container does not ignite at less than 1562 °F (850 °C). Ammonia gas is flammable in air in the range of 16% to 25% by volume. Conditions favorable for ignition are seldom encountered during normal operations due to the high ignition temperature required.

References are shown by bracketed numerals and are listed in the order of appearance in the reference section

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However, the release of ammonia gas into a tightly enclosed or inadequately ventilated space can result in the accumulation of a flammable mixture that can cause a combustion explosion if a high temperature ignition source is present.

Table 1—Physical properties of ammonia [4] Customary Units

Chemical formula Molecular weight Boiling point at 1 atm Critical density Critical pressure Critical temperature Density of liquid at 70 °F (21.1 °C) Density of the gas at 32 °F (0 °C) and 1 atm Flammable limits (% in air, by volume) Freezing point at 1 atm Heat of solution extrapolated to 0% concentration by weight at 28% concentration by weight Ignition temperature (in presence of iron catalyst) (in standard quartz container) Latent heat effusion at -107 9 °F (-77.72 °C) Latent heat of vaporization at boiling point and 1 atm Liquid density at -28 °F (-33.3 °C) and 1 atm Solubility in water vol(liq )/vol(liq.) at 68 °F (20.0 °C) Specific gravity of liquid at -28 °F (-33.3 °C) [water at 39.2 °F (4 °C) = 1] Specific gravity of the gas at 32 °F (0 °C) and 1 atm (air = 1) Specific heat of gas at 59 °F (15 0 °C) and 1 atm constant pressure, Cp constant volume, C„ Ratio of specific heats [CJCp Specific volume of vapor at 32 °F (0 °C) and 1 atm Vapor density at -28 °F (-33.3 °C) and 1 atm Vapor pressure at 70 °F (21 1 °C) Triple point Weight of liquid per gallon at 60 °F (15 6 °C)

SI Units

nh3

nh3

17.031 -28 °F 14.7 Ib/ft3 1657 psia 271.4 °F 38.00 Ib/ft3 0.0481 Ib/ft3 16% to 25% -107.9 °F

17.031 -33.3 °C 236 kg/m3 11 425 kPa, abs2 133.0 °C 608 7 kg/m3 0.771 kg/m3 16% to 25% -77.72 °C

347.4 Btu/lb 214 9 Btu/lb

8.081 x 105 J/kg 4.999 x 105 J/kg

1204 °F 1562 °F

651.1 °C 850.0 °C

142.8 Btu/lb 589.3 Btu/lb

332.2 kJ/kg

1371 kJ/kg

42.57 Ib/ft3 0.848

681 9 kg/m3 0.848

0.6819

0 6819

0.5970

0.5970

0 5232 Btu/(lb °F) 0 3995 Btu/(lb °F) 1.3096 20.78 ft3/lb 0.0555 Ib/ft3 114 1 psi

2 191 kJ/(kg °C) 1 673 kJ/(kg °C) 1 3096 1 297 m3/kg 0.8890 kg/m3 786.7 kPa -77 70 °C at 6.1 kPa, abs 616 8 kg/m3

-107.86 °F at 0.88 psia 5.147 Ib/gal

1.3.5 Under some circumstances, ammonia and ammonium compounds can react with other chemicals to form explo¬ sive products. Ammonia should never be combined with other chemicals unless the possible reactions have been adequately investigated and appropriate precautions taken. See National Fire Protection Association (NFPA) 45, Standard on Fire Protection for Laboratories Using Chemicals [6].

1.3.6 Although most metals are not attacked by ammonia, zinc, copper, and copper base alloys such as brass are subject to rapid deterioration by ammonia. Certain high tensile strength steels have developed stress corrosion cracking in ammonia contaminated with small quantities of air. Such cracking can be minimized by the consistent use of 0 2% water by weight in the ammonia as an inhibitor. Weld heat affected zones can be areas of high 2

kPa shall indicate gauge pressure unless otherwise noted as (kPa, abs) for absolute pressure and (kPa, differential) for differ¬ ential pressure All kPa values are rounded off per CGA P-11, Guideline for Metric Practice in the Compressed Gas Industry [5]

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hardness that are susceptible to stress corrosion cracking. U.S. Department of Transportation (DOT) regulations require that ammonia cargo tanks constructed of such steels be postweld heat treated. See Title 49 of the U.S. Code of Federal Regulations (49 CFR) 173.315 [7],

Ammonia exposure

1.4

1.4.1 At low concentrations, ammonia gas is irritating to the eyes, skin, and mucous membranes of the nose, throat, and lungs. At higher concentrations, ammonia is corrosive to human tissue and possibly life threatening. Table 2 indicates human physiological responses to various concentrations of ammonia in air. See 4.1 regarding exposure to liquid ammonia. Table 2—Human physiological responses to various concentrations of ammonia in air % Ammonia/Time

Concentration/Time

Effect

20 ppm to 50 ppm

0.002% to 0 005%

Mild discomfort, depending on whether an in¬ dividual is accustomed to smelling ammonia

50 ppm to 80 ppm for 2 hr

0 005% to 0.008% for 2 hr

Perceptible eye and throat irritation

100 ppm for 2 hr

0.01% for 2 hr

Nuisance eye and throat irritation

134 ppm for 5 min

0.0134% for 5 min

Tearing of the eyes, eye irritation, nasal irrita¬ tion, throat irritation, chest irritation

140 ppm for 2 hr

0 0140% for 2 hr

Severe irritation, need to leave exposure area

300 ppm to 500 ppm for 30 min [8]

0.03% to 0.05% for 30 min

Upper respiratory tract irritation; tearing of the eyes (lacrimation), hyperventilation

700 ppm to 1700 ppm

0 07% to 0 1 7%

Incapacitation from tearing of the eyes and coughing

5000 ppm to 10 000 ppm

0.5% to 1 0%

Rapidly fatal

10 000 ppm

1 0%

Promptly lethal

Ammonia exposure limits and guidelines

1.4.2

The pungent odor of ammonia is readily detectable by most people and serves as its own warning. Concentra¬ tions in the range of 5 ppm to 53 ppm as referenced in National Academies’ Acute Exposure Guideline Levels for Selected Airborne Chemicals are readily detectable and it is therefore unlikely that any individual would be¬ come overexposed unknowingly [9], Some exposure limits and guidelines for ammonia are shown in Tables 3 and 4. See National Institute for Occupational Safety and Health (NIOSH) Pocket Guide to Chemical Hazards, Title 29 of the Code of Federal Regulations (29 CFR) 1910.1000, and American Industrial Hygiene Association (AIHA) Emergency Response Planning Guidelines (ERPG) [10, 11, 12], Table 3— Regulatory ammonia exposure limits NIOSH Immediately dangerous or life or health (IDLH)

300 ppm [8]

NIOSH Recommended Exposure Limit (REL)

25 ppm (18 mg/m3) 10 hr Time-Weighted Average (TWA) [10]

NIOSH Short-term exposure limit (STEL)

35 ppm (27 mg/m3) 15 min TWA [10]

Occupational Safety and Health Administration (OSHA) Permissible exposure limit (PEL)

50 ppm (35 mg/m3) 8 hr TWA [11 ]

NOTES 1

IDLH. STEL, and PEL are defined in Section 2 of this standard

2

TWA —Time-Weighted Average concentration in contaminated air by volume for up to an 8 hr (OSHA) or 10 hr (NIOSH) workday during a 40 hr workweek

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Table 4— Emergency response planning guideline exposure limits [12] Ammonia (CAS No. 7664-41-7) ERPG 1

The maximum airborne concentration below which it is believed nearly all individuals could be exposed for up to 1 hr without experiencing other than mild, transient adverse health effects of without perceiving a clearly defined objectionable odor.

25 ppm

ERPG-2

The maximum airborne concentration below which it is believed nearly all individuals could be exposed for up to 1 hr without experiencing or developing irreversible or other serious health effects or symptoms that could impair an individual's ability to take pro¬ tective action.

150 ppm

ERPG-3

The maximum airborne concentration below which it is believed nearly all individuals could be exposed for up to 1 hr without experiencing or developing life-threatening health effects

750 ppm

1.5

Federal, state, and local regulations

Anhydrous ammonia is regulated by agencies including DOT, OSHA, Department of Homeland Security (DHS), Environmental Protection Agency (EPA), and state/local jurisdictions.

Hazardous material classification

1.6

DOT designates the hazard class for anhydrous ammonia as 2.2 for domestic shipments and lists ammonia as a hazardous substance with a reportable quantity (RQ) of 100 lb (45 kg). The words "Inhalation Hazard” shall be included on shipping papers and on containers and cylinders as required by special provision 13 noted in column 7 of the hazardous material table. See 49 CFR 172.101 and 172.102(c) [7]. The four-digit United Nations (UN) identification number for ammonia is 1005. In Canada, regulations are published in Transport Canada’s Transportation of Dangerous Goods Regulations and Regulations for the Transportation of Dangerous Commod¬ ities by Rail [13, 14], Under Canadian Transportation of Dangerous Goods Regulations, ammonia is classified as a Toxic Gas 2.3 (8) and may be transported to, through, and from the United States into Canada using this description with proper markings and placarding [13].

2

Definitions

For the purpose of this standard, the following definitions apply.

2.1

Publication terminology

2.1.1 Shall Indicates that the procedure is mandatory. It is used wherever the criterion fnr conformance to specific recom¬ mendations allows no deviation. 2.1.2 Should Indicates that a procedure is recommended.

2.1.3 May Indicates that the procedure is optional.

2.1.4

Will

Is used only to indicate the future, not a degree of requirement.

2.1.5 Can Indicates a possibility or ability.

2.2

Technical definitions

2.2.1 Actuation system System, mechanical or otherwise, which is manually activated to cause the closing of emergency shutoff valves or internal valves stopping the flow of the product in the system.

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Air-purifying respirator

2.2.2

Air-purifying device with full face piece approved by NIOSH under the provisions of Title 30 of the U.S. Code of Federal Regulations (30 CFR) Part II, Subpart I for use in an ammonia contaminated atmosphere in compliance with 29 CFR 1910.134 and selected in accordance with ANSI Z88.2, Respiratory Protection [15, 11, 16], NOTE—A respirator of the air-purifying type shall be used only in an atmosphere containing 19.5% to 22.0% oxygen by volume.

Alteration

2.2.3

Change in any item described in the original manufacturer’s data report that affects the pressure containing capability of the container.

—Rerating a container by increasing maximum allowable working pressure (MAWP) or by increasing or decreasing allowable working temperature is an alteration.

NOTE

Ammonia application unit

2.2.4

Implement of husbandry used to apply ammonia below the soil surface with ammonia supplied by an applicator

tank or nurse tank. NOTE—Commonly known as an applicator or toolbar.

Ammonia or anhydrous ammonia 2.2.5 Compound formed by the chemical combination of the elements nitrogen and hydrogen in the molar proportion of 1 part nitrogen to 3 parts hydrogen.

—

NOTE This relationship is shown by the chemical formula, NH3. On a weight basis, the ratio is 14 parts nitrogen to 3 parts hydrogen or approximately 82% nitrogen to 18% hydrogen. Ammonia can exist in a gaseous, liquid, or solid state. It is not to be confused with aqua ammonia (ammonium hydroxide), which is a solution of ammonia in water.

—

NOTE These terms are used interchangeably in this standard.

Approved

2.2.6

•

Listed by a recognized testing laboratory;

•

Recommended by the manufacturer as suitable for use with anhydrous ammonia and so marked; or

•

Accepted by the AHJ.

—

NOTE The phrase “authority having jurisdiction” is used in a broad manner since jurisdictions and approval agencies vary, as do their responsibilities. Where public safety is primary, the AHJ may be a federal, state, local, or other regional department or individual such as a fire chief, fire marshal, chief of a fire prevention bureau, labor department, health department, building official, electrical inspector, or others having statutory authority. For insurance purposes, an insur¬ ance inspection department, rating bureau, or other insurance company representative may be the AHJ. In many circum¬ stances, the property owner or his designated agent assumes the role of the AHJ; at government installations, the com¬ manding officer or departmental official may be the AHJ.

2.2.7 Appurtenance Devices such as pressure relief devices (PRDs), liquid level gauging devices, valves, pressure gauges, pressure regulators, fittings, metering, or dispensing devices designed to be attached to an ammonia container. Backpressure check valve 2.2.8 Device that allows liquid or gas to flow in only one direction. Breakaway coupling device Automatic, self-closing device designed to disconnect and stop the flow of product from hose connection(s) case of detachment.

2.2.9

in

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Codes

2.2.10.1 American Petroleum Institute—American Society of Mechanical Engineers Code Code that applies to the construction of unfired pressure vessels and per this standard refers lu the Anieiiuan Petroleum Institute (API) and American Society of Mechanical Engineers (ASME) Code for Unfired Pressure Vessels for Petroleum Liquids and Gases [17]. NOTE -The API-ASME Code, as a joint publication and interpretation service, was an alternative code of construction for pressure vessels that was discontinued as of December 31,1956, and construction of containers to the API-ASME Code has not been authorized since July 1, 1961. See also 5.1.1 and 5.1.2.

2.2.10.2 American Society of Mechanical Engineers Code (ASME Code) Code that applies to the construction of unfired pressure vessels and per this standard refers to either Paragraphs U-68, U-69, U-200, or U-201 of Section VIII of the ASME Boiler and Pressure Vessel Code 1949 Edition or Section VIII Division 1 of the ASME Boiler and Pressure Vessel Code 1950 Edition, through the current edition including addenda, Section VIII Division 2 addenda, and applicable Code Case Interpretations, and the applica¬ ble requirements of Sections II, V, and IX [18],

National Board Inspection Code (NBIC) 2.2.10.3 Code that applies to the repair and alteration of unfired pressure vessels and per this standard refers to the NBIC, the latest edition at the time the pressure vessel is repaired or altered [19]. NOTE—This code governs repairs and alterations to tanks of many different codes of construction but relative to this standard refers either to ASME or to API-ASME code pressure vessels, and to the edition of said codes in effect at the time of the tank's construction. All applicable sections of the NBIC apply [19], See also 5.2.4.

2.2.11 Capacity Total volume of the container measured in standard U.S. gallons unless otherwise specified. Cargo tank 2.2.12 Any container designed to be permanently attached to, or forming a part of, a highway motor vehicle, or any container not permanently attached to a highway motor vehicle, that by reason of the container’s size, construc¬ tion, or attachment to a highway motor vehicle, shall be loaded or unloaded without being removed from the highway motor vehicle. NOTE

—This definition does not apply to cylinders and implements of husbandry or containers normally used for storage.

2.2.13 Chemical splash goggles (or goggles) Flexible fitting chemical-protective goggles with a hooded indirect ventilation system to provide primary protection of the eyes and eye sockets from the splash of hazardous liquids that are designed to meet the requirements of ANSI Z87.1 , Practice for Occupational and Educational Eye and Face Protection [20],

—

NOTE Direct vented goggles do not comply with this definition.

2.2.14 Container All tanks, except cylinders as defined in 2.2.15, used for the transportation or storage of anhydrous ammonia.

2.2.15

Cylinder

Pressure vessel of 1000 lb (450 kg) water capacity or less constructed in accordance with DOT specifications for cylinders and authorized for the transportation of ammonia. NOTE—This definition does not include storage tanks, cargo tanks, portable tanks, implements of husbandry, or tank cars.

2.2.16 Design pressure Identical to the maximum allowable working pressure (MAWP) used in the ASME Code [18],

2.2.17

Department of Transportation regulations

Refers to the Hazardous Materials Regulations (HMR) of DOT. NOTE

—See 49 CFR Parts 100 to 180, including "Specifications for Shipping Containers" [7],

COMPRESSED GAS ASSOCIATION, INC

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2.2.18

PAGE 7

Emergency shower

Shower unit permanently connected to a source of clean water that enables the user to have water cascading over the entire body and otherwise meeting the requirements of ANSI Z358.1, Emergency Eyewash and Shower Equipment [21],

Emergency shutoff valve (ESV) Valve with an actuation system designed to stop the flow of ammonia in an emergency situation.

2.2.19

2.2.20 Eye wash unit Device used to irrigate and flush the eyes with clean water. NOTE—Depending upon the requirements set forth in this standard, the device may be a plumbed unit, permanently con¬ nected to a source of clean water, or it may be a self-contained unit, not permanently installed that shall be refilled or replaced after use. Any eye wash device shall otherwise meet the requirements of ANSI Z358.1 [21],

Excess flow valve 2.2.21 Devices that are open to allow flow in either direction and designed to automatically shut off the flow of ammonia at a predetermined flow rate in one direction.

Filling density 2.2.22 Percent ratio of the weight of the ammonia permitted in a container to the weight of water at 60 °F (15.6 °C) that the container will hold when full. NOTE—1 lb of water = 27.74 in3 (455 ml) at 60 °F (15.6 °C). For determining the water capacity of the tank in lbs, the weight of 1 gal (231 in3) (3.785 L) of water at 60 °F (15.6 °C) in air shall be 8.328 lb (3.778 kg).

2.2.23

Full face shield

Device meeting the requirements of ANSI Z87.1, designed to provide protection to all of the face from hazards but shall only be worn as secondary eye protection, supplementing the primary eye protection afforded by chem¬ ical splash goggles [20].

2.2.24

Hydrostatic relief valve (HRV)

Pressure relief device (PRD) for liquid service designed to prevent excessive pressure due to thermal expansion when a pipe or hose is filled with liquid such as between block valves or blinds.

Immediately dangerous to life or health (IDLH) 2.2.25 Maximum concentration from which unprotected persons are able to escape within 30 minutes without escapeimpairing symptoms or irreversible health effects. 2.2.26

Implement of husbandry

System, including a nurse tank, with a capacity of 3000 gal (11.35 m3) or less or an applicator tank, used for transporting and applying anhydrous ammonia containing 0.2% water exclusively for agricultural purposes.

2.2.27

Internal valve

Container primary shutoff valve that can be closed remotely and incorporates an internal excess flow valve with the seat and seat disk located within the container in a manner to remain in place in the event of external damage to the valve and/or associated piping, Mechanically secure point 2.2.28 Any mechanical connection point to be affixed to the ammonia application unit, other implement, and nurse tank wagon, and affixed to a towing implement for the attachment of hose(s). NOTE—The mechanically secure the event of detachment.

2.2.29

point provides

sufficient resistance allowing the breakaway coupling device to

operate in

Permissible exposure limit (PEL)

The limit developed by OSHA for the maximum airborne concentration of a contaminant to which an employee may be exposed over the duration specified by the type of PEL assigned to that contaminant. NOTE—PELs are set forth in 29 CFR 1910.1000 [11],

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CGA G-2.1—2023

2.2.30 Permanent storage installation System employing a stationary (fixed) container used exclusively for storage or supply. 2.2.31 Portable tank Bulk packaging (except a cylinder having a water capacity of 1000 lb [450 kg] or less) designed primarily to be loaded onto, or on, or temporarily attached to a transport vehicle or ship and equipped with skids, mountings, or accessories to facilitate handling of the tank by mechanical means. NOTE—It does not include a cargo tank, tank car, multi-unit tank, or trailer carrying 3AX, 3AAX, or 3T cylinders (as referenced in 49 CFR 171.8) [7],

2.2.32 Positive pressure self-contained breathing apparatus (SCBA) Full face piece respirator, approved by NIOSH/Mine Safety and Health Administration (MSHA), for respiratory protection for both entry into or escape from oxygen-deficient atmospheres or a concentration of gases or vapors that are immediately dangerous lo life oi health where the supply of air is carried by the wearer. NOTE—The air pressure inside the face piece is positive in relation to the air pressure of the outside atmosphere during exhalation and inhalation.

2.2.33 Pressure relief valve (PRV) Pressure relief device (PRD) designed to open to prevent an increase in internal fluid pressure in excess of a specified value due to an emergency or abnormal condition and to close and prevent further flow after normal conditions have been restored. 2.2.34 Protective gloves, boots, and suits Items made of rubber or other material impervious to ammonia.

—

NOTE Gloves refer to gauntlet-style of sufficient length to allow for cuffing, which provide thermal protection suitable for ammonia exposure.

2.2.35

Recommended exposure limit (REL)

Occupational exposure limits for airborne concentration of a contaminant to which an employee may be exposed

over the duration specified and recommended by NIOSH.

2.2.36

Repair

Work necessary to restore a container, cylinder, or system to a safe and satisfactory operating condition provided there is, in all cases, no deviation from the original design. NOTE—Repairs include the addition or replacement of pressure or nonpressure parts, which do not change the design tem¬ perature or pressure of the container, cylinder, or system.

2.2.37

Semitrailer

Any highway motor vehicle with or without motive power designed to be drawn by another motor vehicle and so constructed that some part of its weight and that of its load rests upon or is carried by the towing vehicle.

2.2.38

Short-term exposure limit (STEL)

15 minute Time-Weighted Average (TWA) exposure to an air contaminant that should not be exceeded at any time during a work day and should not be repeated more than four times a day. NOTE—Exposures at the STEL should not occur at less than 60 minute intervals.

2.2.39 System Assembly of equipment consisting essentially of the container or containers, hoses, appurtenances, pumps, compressors, and interconnecting piping.

2.2.40

Trailer

Any highway motor vehicle with or without motive power designed to be drawn by another motor vehicle and so constructed that no part of its weight except the towing device rests upon the towing vehicle. NOTE—Normally called a "full trailer”.

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Transfer, fill, and charge 2.2.41 These terms may be used interchangeably and mean movement of a quantity of ammonia from one container to another container or cylinder. This does not include feeding ammonia to an application device or process.

3

Safety

It is important that personnel understand the properties of ammonia and that they be thoroughly trained in safe practices for its storage and handling. Some of the important physical properties of ammonia are listed in Table 1.

3.1

Training

Prior to such activity, any person required to handle, transfer, transport, or otherwise work with ammonia shall be trained to understand the properties of ammonia, to become competent in safe operating practices, and to take appropriate actions in the event of a leak or an emergency. Federal, state, and/or local regulations as well as site specific requirements shall be followed for training content and frequency Refresher training should be completed at least every 3 years.

3.2

Normal conditions

Any person making, breaking, or testing any ammonia connection, transferring ammonia, or performing mainte¬ nance or repair on an ammonia system under pressure, shall wear protective gloves and chemical splash gog¬ gles. A full face shield may be worn over the goggles. However, a face shield shall not be worn as a substitute for a primary eye protection device (goggles). Any person making, breaking, or testing any ammonia connection and transferring ammonia should do so in accordance with written operating procedures.

3.3

3.3.1

Emergency planning and response coordination Training and personal protective equipment

Only personnel trained for and designated to handle emergencies should attempt to stop a leak. See 29 CFR 1910.120 [11], Respiratory equipment of a type suitable for ammonia shall be worn. All persons not so equipped shall leave the affected area until the leak has been stopped. See Sections 8, 9 and 10 of CGA G-2, Anhydrous Ammonia, regarding recommended exposure, emergency, safety, security, and training procedures [22],

3.3.2

Planning and coordination

Sites handling anhydrous ammonia should preplan for emergencies. This planning should include local emer¬ gency planners and/or responders such as local fire departments, police/law enforcement, federal, state and/or local agencies and address release recognition, prevention, notification, coordination of response actions, and evacuation and/or shelter in place protections.

3.3.3 3.3.3.1

Notifications and reporting releases

Reporting

Unintentional releases over the RQ amount require certain immediate notifications which include, but are not limited to, the National Response Center (NRC), State Emergency Response Commission (SERC) and the Local Emergency Planning Committee (LEPC). The federal RQ for ammonia is 100 lb (45 kg) within a 24 hr time period. Some state regulations may have lower RQ values and/or more restrictive reporting requirements There may be additional federal, state, and/or local agencies that require notifications Releases incidental to transportation are also subject to release reporting requirements under DOT and may require notification to the NRC. See sections 12.9 and 12.10 in CGA G-2 and 49 CFR 171.15 [22, 7],

For more information, see appropriate organizations websites.

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CGA G-2.1 2023

Notifications

Facilities that have 500 lb (227 kg) or more of ammonia on-site at any one time are required to initially notify SERC, LEPC, and the local fire department of this situation and identify a facility coordinator. Foi moie infuimation, see Title 40 of the U.S. Code of Federal Regulations (40 CFR) Part 355 [23].

Emergency plans

3.3.4 3.3.4.1

Facilities

Sites handling anhydrous ammonia should have an emergency action plan (EAP) or an emergency response plan (ERP). Elements of these plans can be found in 29 CFR 1910.38 for EAPs or 29 CFR 1910.120 (q) for ERPs

[11], Sites with anhydrous ammonia may also be subject to:

•

OSI lA’s Process Safety Management (PSM) under 29 CFR 1910.119 [10];

• • •

EPA's Risk Management Program (RMP) under 40 CFR 68 [23]; DOT'S Site Security under 49 CFR 172.800 [7]; and

DHS’ Chemical Facility Anti-Terrorism Standard (CFATS) under 6 CFR Part 27 [24],

These standards also have emergency planning requirements. Sites with less than threshold quantities may be subject to the OSHA and EPA General Duty Clause to maintain and operate a safe system. 3.3.4.2

Transportation

Transportation personnel should also be aware of what actions to take or not to take in the event of a release incidental to transportation. See 49 CFR 177.840 (I) [7],

Permanent storage installations

3.4

At a minimum, all permanent storage installations shall have on hand, readily accessible, and in a serviceable condition, the following equipment for personal protection and first aid purposes.

3.4.1 At indoor facilities, where ammonia is present and employees may be working, a minimum of two emergency escape-only respirators shall be provided at a prominent and marked location(s). The escape-only respirator and training shall be in compliance with 29 CFR 1910.134 [10], For emergency response respiratory protection, see 3.3.1.

3.4.2 One pair of protective gloves impervious to ammonia for each of the maximum number of employees that may be storing, handling, transferring, or otherwise working with anhydrous ammonia at the same time, plus at least one spare pair of said protective gloves.

3.4.3

Chemical splash goggles or chemical splash goggles with full face shield to be worn over the device (goggles) for each of the maximum number of employees that may be involved with storing, handling, transferring, or oth¬ erwise working with anhydrous ammonia at the same time, plus at least one spare pair of said protective goggles.

—

NOTE A full face shield, if used shall only be worn as secondary eye protection supplementing the primary eye protection afforded by the chemical splash goggles A face shield is not to be worn as a substitute for a proper primary eye protection device (goggles)

3.4.4 One pair of protective boots impervious to ammonia.

CGA G-2.1—2023

COMPRESSED GAS ASSOCIATION, INC.

PAGE 11

3.4.5 One protective slicker and/or protective pants and jacket, all impervious to ammonia.

3.4.6 Easily accessible emergency shower and a plumbed eye wash unit or at least 150 gal (570 L) of clean water in an open top container.

—

NOTE It is recommended that the distance from the point of greatest potential exposure to ammonia to the emergency water supply should not exceed ten seconds travel time or 55 ft (16.8 m). Emergency water should be available at each transfer location at the facility and should not have any obstacles or impediments in the way of travel

3.4.7 A reliable emergency communication system shall be easily accessible when employees are present, or transfer of ammonia occurs.

Cargo tanks

3.5

Each cargo tank transporting ammonia (except an implement of husbandry) shall carry and have readily acces¬ sible:

•

For first aid purposes, at least 5 gal (20 L) of clean water in a container designed for flushing any area of the body contacted by ammonia;

•

One pair of protective gloves impervious to ammonia;

•

A full face piece air-purifying respirator with an ammonia canister and at least one spare canister or an escape-only respirator;

•

Chemical splash goggles or chemical splash goggles with full face shield; and

•

Emergency response information as required by DOT per 49 CFR 172.602 [7],

—

NOTE A full face shield, if used, shall only be worn as secondary eye protection supplementing the primary eye protection afforded by the chemical splash goggles. A face shield is not to be worn as a substitute for a proper primary eye protection

device (goggles).

3.6

Leaks in transportation equipment

If a leak occurs in transportation equipment and it is not practical to stop the leak, the driver should make every effort possible, including moving the vehicle to an isolated location downwind from populated communities or heavily traveled highways, to transfer the contents to another approved ammonia container Local authorities should be notified and assistance requested as needed.

3.7

Cylinder and DOT portable tank installations

At ammonia installations comprising cylinders and DOT portable tanks, the employer shall provide ready access to a supply of clean, running water for emergency use or a self-contained eye wash unit with clean water, includ¬ ing provision for flushing of the eyes by an employee in the event of contact with ammonia.

3.8

Site security

Facilities should address and mitigate risks of a possible ammonia release from a wide range of threats such as vandalism, ammonia theft, sabotage, and terrorism, in order to protect the facility, employees and the surrounding community See 6.7.1 and CGA P-50, Standard for Site Security for more information [25], Facilities may be required to address site security under DOT and/or DHS regulations. This may entail a security vulnerability assessment (SVA) and a plan of action to assess the outcome of the SVA.

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CGA G-2.1—2023

Use of water in emergencies

4.1

Human exposure

4.1.1 If liquid ammonia comes in contact with the skin or eyes, the affected area should be promptly and thoroughly flushed with clean water fot at least 15 minutes or more (preferably 20 minutes to 30 minutes but not less than 15 minutes), with the eyes receiving first attention. Eyelids shall be held open during flushing. Skin irrigation should include the ears, chin, neck, armpits, and groin areas as appropriate. Contaminated clothing should be removed only after it is thawed. Do not use neutralizing solutions or ointments on the affected areas. Water used for flushing should be within a temperature range and at a controlled flow rate to avoid causing the patient addi¬ tional injury or discomfort [21J. A physician should treat all cases of exposure to liquid ammonia. An ophthalmol¬ ogist should be consulted immediately after flushing in the event of eye exposure.

4.1.2 If ammonia has entered the nose or throat and the person can swallow, have the person drink large quantities of water. Never give anything by mouth to an unconscious person.

4.2

Accidental release

In the event of an accidental release neither due to fire nor any other heat impingement, the concentration of ammonia vapor in the air can be reduced effectively by the use of adequate volumes of water applied through spray or fog nozzles. Control should be achieved from a safe location, outside the cloud, by directing water fog nozzles into the path of the ammonia plume in order to prevent the ammonia plume from moving away from the release area. See 3.3. Water generally should not be directly applied to liquid ammonia spills as it generates heat and can increase vaporization A water fog or spray can be used to control the vapor emanating from the pool. In the event of a large vapor release from a container, the tank should not be sprayed with water. Under these circumstances, water fog or spray should be applied to the vapor.

4.3

Fire exposure

If an ammonia container is exposed to fire and cannot be moved, water fog or spray should be used to cool it. Use caution if flame impinges on the container because violent rupture of the container is possible. If the fire cannot be controlled and it appears the tank can rupture, the surrounding area should be evacuated to a safe distance in all directions.

4.4

Absorption in water

4.4.1 If ammonia is leaking from a container, the safest, practical means should be taken to stop or abate the leak. If the leak cannot be stopped, the liquid ammonia should be fed to the point of use or transferred to another suitable ammonia container and vapor ammonia captured or burned. Small quantities of ammonia from a leaking con¬ tainer can be absorbed by discharging into a vessel containing approximately 1 gal (4 L) of water for every 1 lb (0.5 kg) of ammonia. The ammonia should be injected into the water as near the bottom of the vessel as practical, if a hose is used to inject ammonia into water, the hose shall be weighted or secured so that the end of the hose will remain near the bottom of the vessel. An approved sparging device is recommended, if available.

4.4.2 Runoff of ammonia contaminated water into drains such as storm or sanitary, streams, or other bodies of waler should be avoided when possible. Contaminated water should be contained and collected, if possible, to prevent environmental consequences. Releases of ammonia shall be reported to regulatory authorities as may be ap¬ propriate and required by law.

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Basic rules

This section applies to all sections of this standard unless otherwise noted.

Equipment and systems

5.1 5.1.1

The provisions of 5.2 shall not be construed as prohibiting the continued use or reinstallation of containers con¬ structed and maintained in accordance with the 1949, 1950, 1952, 1956, 1959, 1965, 1968, 1971, 1974, 1977, 1980, 1983, 1986, 1989, 1992, 1995, and 1998 editions of the ASME Code, or any revisions thereof, in effect at the time of fabrication. Reinstalled stationary pressure vessels of 10 000 gal minimum water capacity shall be subject to the following.

5.1.1.1 Any pressure vessel used as a storage tank shall have been registered with the National Board, or in lieu of National Board Registration, shall have available, direct from the manufacturer, an ASME manufacturer’s data report or be subject to testing per the requirements of 5.1.1.5.

5.1.1.2 Any pressure vessel used as a storage tank shall have either a 250 psi (1724 kPa) maximum allowable working pressure (MAWP) or shall have been rerated for a 250 psi (1724 kPa) MAWP in full accordance with the National Board Inspection Code (NBIC) including, “Authorized Inspection”.

5.1.1.3 Any pressure vessel used as a storage tank shall have:

•

been stress relieved during fabrication in accordance with the code in effect at the time of fabrication;

•

cold-formed heads that have been stress relieved; or

•

been fabricated with hot-formed heads.

If the code in effect at the time of fabrication did not require one of the previous forms of heat treatment after fabrication, the vessel shall be subject to testing per the requirements of 5.1.1. 5.

5.1.1.4 In addition to a fully-legible data plate, an ASME manufacturer’s data report, including any applicable ASME manufacturer's partial data report, obtainable directly from the National Board, or in lieu of National Board Reg¬ istration, ASME manufacturer’s data report(s) obtainable directly from the manufacturer may be used by the AHJ to verify the pressure vessel identity (including its data plate information) through conformity with its specifica¬ tions, to verify 5.1.1.1 through 5.1.1.3, and to detect post fabrication welding to the pressure vessel.

5.1.1.5 When testing is required by 5 1 1.1 or 5.1.1.3, it shall be performed before ammonia is introduced, and shall consist of:

•

Nondestructive testing for weld defects [22];

•

Nondestructive testing for weld defects within the heat-affected zones shall be required for at least 25% of vessel welds with emphasis on longitudinal welds. If indication of stress corrosion cracking is found, further testing of up to 100% of the welds is required;

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CGA G-2.1—2023

•

Storage containers with manways shall be examined internally by means of the wet fluorescent magnetic particle testing method. Persons performing magnetic particle testing and interpreting the results thereof shall be experienced and qualified in the proper procedures. See Section V of the ASME Code, Nondestruc¬ tive Examination and see CGA P-26, Guidelines for Inspection and Repair of MC-330 and MC-331 Anhydrous Ammonia Cargo Tanks, for information regarding recommended equipment, inspection and re¬ pair procedures, and safe tank entry procedures [18, 26], Alternate recognized evaluation techniques such as acoustic emission and fracture mechanics analysis may be substituted for internal inspection. See 6.5 of API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration for guidance [27]. Re-examination of such containers should be repeated at not more than 10 year intervals, except that an inspection frequency of more or less than 10 years may be assigned upon a vessel-specific basis through the use of a risk-based inspection (RBI) assessment performed in accordance with API RP 580, Risk-Based Inspection and API RP 581, Risk-Based Inspection Technology procedures by a qualified organization [28, 29], The RBI recommendation shall be submitted in writing by the qualified organization. Acceptance-rejec¬ tion criteria shall be in accordance with ASME Code Section VIII [18]; and

•

Thickness testing [??]■

•

Thickness testing is required to confirm the minimum wall thickness of the shell and both heads to main¬ tain a 250 psi (1724 kPa) rating

• Corroded or abraded areas in the shell or heads of a container shall be thickness tested using suitable

equipment and procedures. It is suggested that thickness measurements be made using an ultrasonic device capable of accurately measuring thickness to within at least 0.002 in (0.051 mm) and operated by a qualified person trained and skilled in procedures recommended by the equipment manufacturer. Indications below the minimum wall thickness shall be rejected.

5.1.1.6 The inspection company shall provide a written report detailing the results of the tests per 5.1.1.5, including indications that do not meet the acceptance criteria in 5.1.T.5. Storage containers with rejected indications from the tests in 5.1.1.5 shall not be placed into ammonia service unless suitable repairs and tests are performed. See the NBIC [19], Prospected buyers of any storage tank tested in accordance with 5.1.1.5 shall be provided with a copy of all test reports.

5.1.2 Systems and components that were fabricated, installed, and maintained in accordance with the American Na¬ tional Standard K61.1, Safety Requirements for the Storage and Handling of Anhydrous Ammonia, CGA G-2.1, Standards for the Storage and Handling of Anhydrous Ammonia and Ammonia Solutions, or The Agricultural Nitrogen Institute Standard M-1, Standard for Storage and Handling of Agricultural Ammonia, in effect at the time of installation, may be acceptable for continued use [30, 31, 32],3 Facilities with existing systems and components designed and constructed in accordance with earlier versions of the previously cited codes, standards, or prac¬ tices that are no longer current, should determine and document that the equipment is sate to continue to use, taking into consideration risk reduction and physical and legal constraints. Facilities with such systems and components are encouraged to conform to the current standard

5.2

Requirements for new construction and original test, repair, and alterations of containers (including DOT portable tanks), other than refrigerated storage tanks

For refrigerated storage tanks, see 7.1.

5.2.1 Containers used with systems covered in Sections 6, 9, 11, and 12 shall be made of steel or other material compatible with ammonia and tested in accordance with the current ASME Code An exception to the

3

These standards are no longer published

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ASME Code requirements is that construction under Table UW 12 at a governing joint efficiency of under 80% is not authorized unless the requirements of UW-11(a)5(b) are met [18].

5.2.2 Containers designed and constructed in accordance with the ASME Code, other than refrigerated storage con¬ tainers, shall comply with the following additional requirements.

5.2.2.1 The entire container shall be postweld heat treated after completion of all welds to the shells and heads. The method employed shall be as specified in the ASME Code, except that the provisions for extended time at lower temperature for postweld heat treatment shall not be permitted. Welded attachments to pads may be made after postweld heat treatment [18],

5.2.2.2 Carbon steels used to fabricate the pressure retaining parts of a container shall not exceed 70 000 psi (483 MPa) minimum specified tensile strength in order to minimize the potential for the development of stress corrosion cracks during service (does not apply to Sections 8, 9, and 10) [23], Experience indicates that containers fabri¬ cated from fine grained and low- to moderate-strength carbon steels (70 000 psi [483 MPa] minimum specified tensile strength) and that have been postweld heat treated in their entirety after completion of all weldments are essentially free of the problem.

—

Exception Implements of husbandry may be fabricated from steel having a specified tensile strength of 75 000 psi (517 MPa). See also 5 2.2.1.

5.2.3 Containers shall be inspected by a person who holds a valid National Board Commission [19]. Exception—Refrigerated storage tanks with a design pressure of 15 psi (103 kPa) or less and containers covered in Section 8.

5.2.4 Repair or alteration of pressure containing parts of a container shall be performed in compliance with the appli¬ cable provisions of the current edition of the NBIC [19], Where specific procedures are not given, it is intended that, subject to acceptance of the inspector, all repair or alteration shall conform as much as possible to the ASME Code section and edition to which the container was constructed [18],

As practical guidance to the user of this standard, the NBIC has many provisions that shall be met. Among these:

•

The firm that completes any repair to a pressure vessel shall hold a valid certificate of authorization to use the copyright-protected repair symbol of the National Board, commonly referred to as an R-stamp. Said R-stamp may authorize repairs to be made at the repair firm or at a field location or both. The prospective repair firm shall be able to display a valid certificate of authorization as previously described upon request;

•

An R-stamp firm is required to hold a valid contract with an Authorized Inspection Agency;

•

The authorized inspector (Al) has several duties, including oversight of the repair firm’s quality manual and oversight of the repair. The repair firm may only complete repairs or alterations within the scope of its quality manual, as approved by the Al. Ultimately for the repair or alteration, in order to qualify as a NBIC repair, the Al shall complete the section titled “authorized inspection” on either the form R-1, Report of repair or the form R-2, Report of alteration; and

•

Per Part 3, Section 5 of the NBIC, the R-stamp firm shall apply the appropriate repair tag to the pressure vessel that displays the copyright-protected repair symbol of the National Board and stamp it with the R-stamp firm's name, R-certificate number, date of repair, and other information as required by the NBIC [19]

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CGA G-2.1—2023

Even if the provision listed in first bullet is met, the absence of any other provisions listed previously in bullet 2, 3, and 4 results in a noncode repair or alteration. From the initial reference to the NBIC in this standard and whether for repairs or alterations, past or future, authorized inspection, proper documentation, and a proper repair tag, properly applied, are all considered by the NBIC Lu be a pail uf Lhe repair [19],

b.2.4.1 Pressurized storage tanks including Section 11 (nurse tanks) shall have a legible dataplate in older lo be repaired or altered. All repairs or alterations to pressurized storage tanks shall be fully compliant with the NBIC, including the authorized inspection.

5.3

Location of containers

5.3.1 Selection of a location for a storage container shall be made considering the potential physiological and environ¬ mental effects of ammonia on the surroundings of the proposed site. Containers shall be located outside of buildings except in buildings or sections thereof specially approved for the purpose.

5.3.2 Containers shall be located at least 50 ft (15 m) from a dug well or other sources of potable water supply unless the container is a part of a water treatment installation. 5.3.3 The minimum distance of a storage container to dwellings or to population centers shall be in accordance with the requirements of the local AHJ.

5.3.4 In the absence of specifications of minimum distance by local jurisdictions, separation distance(s) for new, addi¬ tional or relocated ammonia stationary storage containers and placements of containers covered by Sections 9, 10, 11, and 12 after January 1, 2002, shall be in accordance with Table 5.

5.3.5 Container storage areas shall be accessible to emergency vehicles and personnel.

5.3.6 Areas within 10 ft (3 m) of a storage container shall be maintained clear of dry grass and woods and other combustible materials.

CGA G-2.1—2023

PAGE 17

COMPRESSED GAS ASSOCIATION. INC.

Table 5—Minimum separation distances for location of ammonia storage containers 1'2> Minimum distance from each container to:

Nominal capacity of container 3)

Over 500 gal to 2000 gal 9)

Mainline of railroad 4)

Highway 5) or line of adjoining prop¬ erty that can be built upon

Place of public assembly 6) or residential occupancy 7)

Institutional occupancy 8>

100 ft

25 ft

150 ft

250 ft

Over 2000 gal to 30 000 gal

100 ft

50 ft

300 ft

500 ft

Over 30 000 gal to 100 000 gal

100 ft

50 ft

450 ft

750 ft

Over 100 000 gal

100 ft

50 ft

600 ft

1000 ft

Over 2 m3 to 8 m3

30 m

8m

45 m

75 m

Over 8 m3to 110 m3

30 m

15 m

90 m

150 m

Over 110 m3 to 400 m3

30 m

15 m

140 m

230 m

Over 400 m3

30 m

15 m

180 m

300 m

1>

Separation distances referred to are approximate and based on experience with minor releases.

2>

For additional distances, see 5.3.2, 5.3.3, 5.3.4, 5.3.5, 5.3.6, and 6.4.6.

3)

The nominal capacity of multiple containers shall be aggregated, but only if containers are interconnected and safe¬ guards do not exist to prevent a leak from one container from emptying interconnected containers.

4>

Class II track or better See 49 CFR 213.9 [7],

S)

A highway is defined as a public way for purposes of vehicular travel, including the entire area within right of way. See American Association of State Highway and Transportation Officials (AASHTO) Transportation Glossary (1983) [33],

6>

Public assembly occupancy is a premises or that portion of a premises-where large numbers of people congregate and from which occupants cannot quickly vacate the space. Public-assembly occupancies include, among others, auditoriums, ballrooms, classrooms, passenger depots, restaurants, and theatres. See ANSI/ASHRAE 15, Safety Standard for Refrigeration Systems [34]

7>

Residential occupancy is a premises or that portion of a premises that provides the occupants with complete inde¬ pendent living facilities including permanent provisions for living, sleeping, eating, cooking, and sanitation. Residen¬ tial occupancies include, among others, dormitories, hotels, multi-unit apartments, and private residences. See ANSI/ASHRAE 15 [34],

8>

Institutional occupancy is a premises or that portion of a premises from which, because they are disabled, debili¬ tated, or confined, occupants cannot readily leave without the assistance of others Institutional occupancies include, among others, hospitals, nursing homes, asylums, and spaces containing locked cells. See ANSI/ASHRAE 15 [34],

31

For 500 gal (2 m3) or less, see 5.3.1 and 5 3.3.

5.4

Markings of nonrefrigerated containers and systems other than DOT containers

5.4.1 Each system nameplate, when required, shall be made of a noncorroding metal permanently attached to the system by continuous welding around its perimeter and located so as to be readily accessible for inspection. Nameplates shall be maintained in legible condition and include markings as specified in the following subsec¬ tions. Each container or system covered in Sections 6,9,10 (except ton containers and cylinders), 11 , and 12 shall be marked as follows:

5.4.1.1 With a marking as required by paragraph UG-116 of the ASME Code and identifying compliance with the rules of the ASME Code under which the container is constructed;

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5.4.1. 2 With National Board of Boiler and Pressure Vessel Inspectors stamping to indicate registration of the container with this organization;

5.4.1.3 With a notation on the container and system nameplate to indicate whether the system is designed for above¬ ground or underground installation or both; 5.4.1 .4 With the minimum and maximum temperatures in Fahrenheit (°F) or Celsius (°C) for which the container is de¬ signed;

5.4.1.5 With the wall thickness of the container shell and heads in inches (in) or millimeters (mm);

5.4.1.6

With the water capacity of the container in pounds (lb) or kilograms (kg) or U.S. standard gallons (gal) or cubic meters (m3) at 60 °F (15.6 °C);

5.4.1.7 With the outside surface area of the container in ft2 or m2; and

5.4.1.8 With marking required by paragraph UG-116 of the ASME Code shall be applied in accordance with the require¬ ments of UG-118 or UG-119. Marking required by 5.4.1.3, 5.4.1.4, 5.4.1.5, 5.4.1 6, and 5.4.1.7 shall be stamped on the nameplate required in 5.4.1, following the marking arrangement specified by UG-118 or on a separate nameplate immediately adjacent to the ASME Code nameplate [186], Requirements of 5.4.1 shall also apply to the separate nameplate.

5.4.2 All container openings except for pressure relief valves, pressure indicating devices, thermometer wells, or liquid level indicators shall be identified, marked, stenciled, tagged, or decaled to indicate whether the opening is in contact with the liquid or vapor phase when the container is filled to the maximum allowable filling density.

5.4.3

Storage tanks without dataplates

ASME storage tanks without legible dataplates may have their dataplates replaced by the manufacturer in full accordance with the NBIC (Code of construction=ASME Code).

5.4.3.1

Dataplate replacement per National Boiler Inspection Code

ASME storage tanks without legible dataplates may have their dataplates replaced by the manufacturer in full accordance with the NBIC (Code of construction=ASME Code) providing that:

•

The original manufacturer is in business; and

•

The container owner can show through documentation to the state and local AHJ and to the manufacturer's satisfaction that the pressure vessel in question is the original pressure vessel that it is claimed.

NOTE—As guidance, this may be accomplished through inspection reports that recorded pertinent tank dataplate information, a history of when and where said pressure vessel was located, a form U-1 or form U-1a manufacturer's data report, and a comparison of the data report with the actual pressure vessel regarding outer diameter (OD) and overall length, head type, number of courses and locations, and size of tank openings.

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If these conditions are met, the manufacturer may, at their discretion, fabricate a replacement dataplate that is to be attached to the pressure vessel as witnessed and certified by said jurisdiction. The replacement dataplate will have the copyright protected unfired pressure vessel symbol of the ASME (which only the original manufacturer is eligible to apply).

5.4.3.2

Non-ASME dataplate replacement by state or local AHJ

If the manufacturer is no longer in business, but the storage tank has either National Board Registration or the container owner can produce a copy of the manufacturer’s data report that was obtained directly from the man¬ ufacturer while the manufacturer was in business, then the state or local AHJ may authorize a generic replace¬ ment dataplate, listing all the information as the original dataplate, as verified by a data report, except the re¬ placement dataplate shall not have the copyright-protected "unfired pressure vessel” symbol of the ASME stamped into the replacement. Without the unfired pressure vessel symbol, the tank may be allowed to continue in service or be re-installed within the same state or local AHJ but no other jurisdiction is required to recognize the tank as being an ASME container.

5.4.3.3

Tanks missing dataplates that are not replaceable through 5.4.3.1 or 5.4.3.2

Nonrefrigerated containers (other than DOT containers) not conforming to 5.4.1, shall be inspected and tested to determine the information in 5.4.1.5, 5.4.1.6, and 5.4.1.7. Any nonconforming containers shall be removed from service by the year 2030.

5.5

Container appurtenances

5.5.1 All appurtenances of each system shall be approved. See 2.2.6.

5.5.2 All appurtenances shall be designed for no less than the maximum working pressure of the portion of the system on which they are installed. All appurtenances shall be fabricated from materials proved suitable for anhydrous ammonia service.

5.5.3 All connections to containers except connections for pressure relief devices (PRDs), thermometer well, liquid level gauging devices, or connections fitted with No. 54 (0.055 in or 1.40 mm) drill size orifice orthose plugged, shall have shutoff valves located as close to the container as possible.

5.5.4 Excess flow valves shall be designed to close automatically at the rated flows of vapor or liquid as specified by the manufacturer. The piping, including valves, fittings, and hose, being protected by an excess flow valve shall have a greater capacity than the rated flow of the excess flow valve, so the valve will likely close in case of failure at any point in the line or fittings.

5.5.5 Liquid level gauging devices that require bleeding of the product to the atmosphere and that are so constructed that outward flow will not exceed that passed by a No. 54 (0.055 in or 1.40 mm) drill size opening need not be equipped with excess flow valves.

5.5.6 An opening in a container to which a pressure gauge connection is made need not be equipped with an excess flow valve if the opening is not larger than No. 54 (0.055 in or 1.40 mm) drill size. A manual shutoff valve may be installed between the tank opening and the pressure gauge or pressure indicating device to allow for changing out the gauge/device without reducing tank pressure.

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5.5.7 An excess flow or backpressure check valve, where required in this standard, shall be installed directly in the container opening or a point outside where the line enters the container. In the latter case, the installation shall be made so that any undue strain beyond the excess flow or backpressure check valve shall not cause breakage between the valve and the container.

5.5.8 Excess flow valves shall be designed with bypass, not to exceed a No. 60 (0.040 in or 1.02 mm) drill size opening, to allow equalization of pressure.

5.5.9 Shutoff valves with an Integral excess flow valve shall be designed for proper installation in a container opening so that the excess flow valve will close in the event that the valve body, extending above the coupling, is sheared or broken off.

5.5.10 All excess flow valves shall be plainly and permanently marked or recorded with the name or trademark of the manufacturer, the model number, and the rated capacity.

5.5.11 Each filling connection on nonrefrigerated container opening shall have a positive shutoff valve in conjunction with either an approved internal backpressure check valve or an approved internal excess flow valve as appro¬ priate. Vapor connections on nonrefrigerated containers shall have a positive shutoff valve together with an ap¬ proved internal excess flow valve. Quick opening (1/4 turn) valves are not recommended for use on transfer lines.

5.5.12 All container appurtenances shall be subject to an external visual inspection at least annually to determine that it is free of evidence of tampering, damage, and corrosion that could prevent proper operation and/or leakage. If nonconformances are identified, they shall be addressed.

5.6

Piping, tubing, fittings, valves, and gaskets

All piping shall conform to ASME B31.3, Process Piping except ASME B31.5, Refrigeration Piping and Heat Transfer Components may be used for refrigeration piping systems within its scope [35, 36],

5.6.1 All piping, tubing, fittings, valves, and gaskets shall be made of material suitable for anhydrous ammonia service. Brass, copper, or galvanized steel pipe or tubing shall not be used.

5.6.2 Cast and malleable iron flanges and fittings shall not be used Flanges and fittings used on nonrefriqerated sys¬ tems shall be at least American Society for Testing and Materials (ASTM) A105, Standard Specification for Car¬ bon Steel Forging for Piping Applications [37], Class 300 or greater flanges are recommended. Butt weld fittings used in nonrefriqerated systems shall be at least ASTM A234, Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service, Grade WPB, Schedule 40 or 80 [38], All other flanges, fittings, piping and tubing not specified in this paragraph shall comply with ASME B31.3 or ASME 31.5 [35, 36],

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5.6.3 The wetted metal parts of valves that are subjected to internal pressure should be made of steel, ductile (nodular) iron, or malleable iron. In this case, valves include shutoff valves, excess flow valves, backcheck valves, emer¬ gency shutoff valves, and remotely controlled valves Ductile iron shall meet the requirements of ANSI/ASTM A395, Standard Specification for Ferritics Ductile Iron Pressure Retaining Castings for Use at Ele¬ vated Temperatures and malleable iron shall meet the requirements of ANSI/ASTM A47, Standard Specification for Ferritic Malleable Iron Castings [39, 40], All piping, tubing, and fittings shall be designed for a pressure no less than the maximum pressure to which they can be subjected in service.

5.6.4 All piping shall be supported in accordance with good piping practices, and provisions shall be made as neces¬ sary for expansion, contraction, impact, vibration, and settling.

5.6.5 Piping used on nonrefrigerated systems shall be at least ASTM A53, Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless, Grade B seamless or electric resistance welded pipe [41]. Pipe joints shall be threaded, welded, or flanged. Pipe shall be at least Schedule 40 when joints are welded or welded and flanged. Pipe shall be at least Schedule 80 when joints are threaded. Threaded nipples shall be seamless. Welding shall be done by a welder qualified in accordance with the ASME Code, Section IX, "Welding Qualifications” [18]. Tubing joints shall be made up with flared, flareless, or compression type fittings complying with ANSI/Society of Automotive Engineers (SAE) J513f Refrigeration Tube Fittings-General Specifications, ASME B31.3, or ASME B31.5 [42, 35, 36].

5.6.6 Metal, flexible connections may be used for permanent installations to provide for expansion, contraction, jarring, vibrating, and settling. In no case shall the angle of the connection exceed the manufacturer’s specification. Such connections used for permanent installations shall have double braiding and a minimum working pressure of 350 psi (2410 kPa) (minimum 1750 psi [12 070 kPa] burst pressure). For temporary installations, hose meeting the requirements of 5.7 may be used.

5.6.7 Adequate provisions shall be made to protect all exposed piping from physical damage, which could result from impact by moving machinery, automobiles or trucks, or any other equipment at the facility. See also 6.7.1.

5.6.8

Joint compounds shall be resistant to ammonia at the maximum pressure and temperature to which they can be subjected in service. 5.6.9 After assembly of piping or tubing, not including appurtenances that have joints connected threading of pipe (i.e.. nonfactorv threads), or other methods, joints shall be pressure tested

bv welding, field to either at least 1 1 times for pneumatic (air or nitrogen) or 1.5 times for hydrostatic of the MAWP and maintained for a period of time sufficient to equalize piping strains.

5.6.10 After assembly of the complete piping system, including appurtenances and components, the piping system shall be proven free of leaks bv performing a leak test at not less than the normal operating pressure of the sys¬ tem. Using anhydrous ammonia as a test medium shall be permitted

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5.6.11 Underground piping shall be protected and maintained against external corrosion. Underground piping shall be leak tested at least every 5 years in accordance with 5.6.10.

5.6.12 Metallic and nonmetallic gasket materials such as carbon steel or stainless steel spiral wound synthetic filled are suitable for ammonia service. Other materials such as, but not limited to, polytetrafluoroethylene (PTFE), eth¬ ylene piopylene diene monomer (EPUM), neoprene, and compiessed fiber have also been found suitable, pro¬ vided that they are fully confined in order to prevent creep or blow out in the event of elevated temperature When a flange is opened, the gasket should be replaced. 5.6.13 If color is used as the only identification to indicate whether piping contains liquid or sign shall be displayed.

5.7

vapor ammonia,

a legend

Hose specification

5.7.1 This specification covers hose, 3 in inside diameter (ID) and smaller, commonly referred to as "pressure transfer hose", used to convey anhydrous ammonia liquid or to convey anhydrous ammonia gas where the gas is in contact with liquid ammonia.

It is important to consider the critical application of anhydrous ammonia hose. Dedicated hoses should be used for ammonia transfer service only and should not be used in other services.

5.7.2 Hose with rubber construction and hose constructed with materials other than rubber used in ammonia service and subject to container pressure shall be approved for ammonia service by the hose manufacturer, subject to any stated limitations of use, and conform to 5.7.2, 5.7.3, 5.7.4, 5.7.5, and 5.7.6. Hose with plain carbon steel wire reinforcement is not recommended for compressed gases.

5.7.3 Hose subject to container pressure shall be designed for a minimum working pressure of 350 psi (2410 kPa) and a minimum burst pressure of 1750 psi (12 070 kPa). Hose assemblies, when made up, shall be capable of withstanding a test pressure of 525 psi (3620 kPa).

5.7.4 Hose and hose connections located on the low pressure side of flow control or pressure reducing valves on devices discharging to atmospheric pressure, shall be designed for the maximum low side working pressure and approved for ammonia service by the manufacturer, subject to any stated limitations of use. All connections shall be designed, constructed, and installed so that there will be no leakage when connected.

Shutoff valves on the end of liquid and vapor transfer hoses shall be equipped with a means to enable the operator to safely bleed off pressure before disconnecting the hoses (for example, bleed valves, quick acting minimum loss hose end valves, other engineered systems, etc ).

5.7.5 Where liquid transfer hose is not drained of liquid upon completion of transfer operations, such hose shall be equipped with an approved shutoff valve at the discharge end. Provision shall be made to prevent excessive hydrostatic pressure in the hose. See 5.8.2.1.

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5.7.6 On all rubber hose 0.5 in (13 mm) outside diameter (OD) and larger used in ammonia service and subject to container pressure, the following information shall be etched, cast, or impressed at 5 ft (1.5 m) intervals on the outer hose cover:

Anhydrous Ammonia

XXX psig (Maximum Working Pressure) Manufacturer's Name or Trademark

Year of Manufacture

For hoses other than rubber construction and metal flexible connections (see 5.6.6), the previous information should be affixed on the outer hose end(s).

For all hose, these marks shall be maintained clear and legible.

5.7.7

Visual inspection before each use

At a minimum, before each day’s use the hose assembly shall be visually inspected for possible weaknesses cited in 5.7.8. 5.7.8

5.7.8.1

Possible hose assembly weaknesses Cuts or nicks

Hose found with cuts or nicks in the hose structure that expose the reinforcement material shall be immediately removed from service. Small cuts or nicks in the outer cover that do not penetrate to the braiding shall not be cause for hose rejection unless the cover in the immediate area is loose or the reinforcement material is cut or exposed.

5.7.8.2

Deterioration

Hoses found with damage to the reinforcement material by excessive abrasion, weathering, corrosion or other means, or damage to the outer cover causing exposure of the reinforcement braid shall be immediately removed from service.

5.7.8.3

Blistering

Hoses found with evidence of blistering or loose outer cover shall be immediately removed from service and evaluated to determine the cause and if the hose is suitable for continued service. Once the cover is pulled loose from the hose braid, a pocket develops that could accumulate water and be a possible site for corrosion or rusting. NOTE—Pricking the hose cover is necessary for satisfactory hose performance. A uniformly pricked cover should not be viewed with alarm.

5.7.8.4

Bulges, flat spots, or kinks

Hoses found with evidence of bulges, flat spots, or kinks shall be immediately removed from service

5.7.8.5

Coupling damage or slippage

Hoses found with evidence of coupling slippage, or the appearance ofcracks, severe dents, or excessive corro¬ sion involving couplings or crimped connections, shall be immediately removed from service.

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Hoses found with apparent damage to or excessive wear of the threaded or connecting surfaces of a hose cou¬ pling shall also be immediately removed from service and evaluated to determine (by use of a gauge or template) if the hose is suitable for continued service.

5.7.8.6

Markings

When all markings placed originally on a hose by the manufacturer to identify maximum rated working pressure and other specifications have been obliterated, the hose shall bo immediately removed from service.

For hoses with markings affixed to the outer hose end(s), when the maximum rated working pressure and other specifications have been obliterated, the information shall be immediately reaffixed or the hose shall be immedi¬ ately removed from service.

5.7.8.7

Leaks

Any hose found with leaks shall be immediately removed from service.

5.7.8.S

Maximum service period

Although found free of any observable conditions in accordance with 5.7.2, 5.7.3, 5.7.4, 5.7.5, and 5.7.6, hoses shall be permanently removed from service that have been installed and used over a period of time that exceeds the shorter service life of either:

•

The service life recommended by the manufacturer of the hose; or

•

If used in conjunction with an additive, the service life of the ammonia hose as recommended by the manu¬ facturer of the additive.

If the maximum service period is not specified by the manufacturer, the hose shall be permanently removed after 10 years from the date of manufacture.

5.7.9

Periodic documented visual inspection

Hoses shall be visually inspected at least annually in accordance with 5.7.8. This inspection shall be documented. For hoses subject to DOT regulations such as hoses on cargo tanks, this inspection shall be done in accordance with 49 CFR Subpart 180.407 and 180.416 [7], Hoses used seasonally shall be inspected before each season.

5.7.10

Annual pressure requalification test

Hoses used in ammonia service shall be pressure tested at least annually.

The pressure test requirement does not apply to:

•

hoses installed as a fixed component of a process, for example, hoses that are not removed or reattached at either end routinely as part of normal operations such as flexible metal pipe connectors (see 5.6.6);

•

implements of husbandry with respect to filling and field application; however, pressure testing should be considered for these operations; and

•

hoses used in ammonia service that have a MAWP of 2000 psi (13 790 kPa) or of at least 4 times the MAWP

greater

and a burst pressure

Before pressure testing, the hose shall be visually inspected in accordance with 5.7 8.

Pressure testing shall be completed in accordance with 5.7.10.1.

5.7.10.1

General

Hoses may be pressure tested either pneumatically or hydrostatically. Pressure testing, following the precautions described in 5 7.10.2, should only be performed by qualified personnel [431.

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In either of the pressure test methods described in 5.7 10.1 1 and 5.7 10.1 2, the hose shall be tested at ambient temperature lying flat and straight. With one end of the hose connected to a pressure source that includes an accurate test pressure gauge that has been calibrated within the past one year, and a blowdown valve, the test pressure shall be gradually increased until the maximum test pressure is reached as specified in 5,7.10 1 1 or 5 7 10 12 depending on the test method used. Do not exceed the specified test pressure. To pass the pressure test, the hose shall be pressure tight and without decay for at least 1 minute. If the braid wires start to break or the hose starts to deform during the pressurization of the hose, the blowdown valve shall be opened immediately to depressurize the hose. Any observable leaks, bulges, or other defects shall disgualify the hose from continued use until the defects are repaired in accordance with 5.7 12 [431

The working pressure of the hose assembly includes the hose as well as any attached couplings 1431

5.7.10.1.1

Hydrostatic test

When conducting a hydrostatic test, ensure the corrugations of the hose inner core are completely filled with water to displace any air. This is accomplished by positioning the hose at a slope and filling it with water from the bottom while flexing sections of the hose to a vertical position and shaking the hose to dislodge any air that is contained in the corrugations. This allows the air to escape from the elevated end of the hose The hose shall be hydrostatically tested at 1.5 times the MAWP. The pressure should be raised slowly and incrementally, but not to exceed 50 psi (340 kPa) per minute. The inside of the hose should be dried after testing [431

5.7.10.1.2

Pneumatic pressure test

The pneumatic pressure test may be conducted with dry nitrogen gas or dry, oil-free compressed air. The hose shall be pressurized gradually to a test pressure of 1.1 times the MAWP. The pressure should be raised slowly and incrementally but not to exceed 50 psi (340 kPa) per minute. After remaining at the test pressure for 1 minute, reduce the pressure to MAWP (or 90% MAWP), the hose may be checked for leaks with either of the following methods:

•

Using an oxygen compatible leak check solution applied to the outside of the hose to check for leaks along the entire length, outer circumference, and at the end fittings. Leaks are indicated by the formation of bub¬

bles; or

•

Submerging the entire hose under water after the outside of the hose is shaken free of any retained air. The hose shall be observed for the discharge of any gas or air bubbles for at least 1 minute [431.

5.7.10.2

Precautions

Ensure personnel safety and protect property from damage during pressure testing as follows:

•

Secure the hose along its length to allow free movement, but do not allow whipping, hose extension, or the release of particulates toward test personnel in the case of failure:

•

Contain or orient ends of the hose so a blowout fitting does not cause iniury or damage:

•

Provide personnel with protection against the force of the pressure medium if failure occurs. This protection shall include safety eyewear,

•

Establish a safe zone around the test area to protect personnel from injury in case ofhose failure. Personnel sha11 n ot be allowed in line with the hose ends during a pressure test: and

•

Adeguately protect the pressure test set-up against any overpressure [431

5.7.10.3 For continued service, each hose assembly shall be marked or tagged with the date of Qualification resulting from repair and pressure testing. The Qualification date (month/year) indicating an acceptable pressure test shall be durably marked on the hose, preferably at one of the ends. The hose MAWP shall be legibly marked on the hose assembly for future inspection purposes. Documentation of the Qualification of the hose shall be retained bv the company testing the hose and by the company using the hose [431

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CGAG 2.1

2023

Removal from service

5.7.11

Hoses shall be immediately removed from service when failing inspection or requalification testing or when they have reached their maximum service period. Hoses removed from service shall be disposed of, swapped, ui recycled in a way that it cannot be returned to anhydrous ammonia service.

5.7.12

Hose repair

5.7.12.1

Defect removal

A hose assembly found with any defects as noted in 5.7.2, 5.7.3, 5.7.4, 5.7.5, and 5.7.6 shall be removed from service or the defect eliminated before the hose is returned to service. If an affected length or coupling is cut off to eliminate all defects and the remaining hose recoupled, it should be done by the original manufacturer. Recy¬ cled hose shall be retested in accordance with 5.7.10.1 before returning to service. After a successful pressure test, the hose shall be marked as qualified per 5.7.10.

Pressure relief valves

5.8

5.8.1

Pressure relief valves

5.8.1.1 Every container used in systems covered by Sections 6, 11, and 12 without permanent supply piping to another source of excess pressure shall be protected from excess pressure generated by fire by providing one or more pressure relief valve of the spring loaded type conforming with applicable requirements of ASME UG-125(c)(3); UL-132, Standard for Safety Relief Valves for Anhydrous Ammonia and LP-Gas; or other equivalent pressure relief valve standard [18, 44], For other sources of excess pressure, use ASME UG-125, UG-126, UG-127, UG-128, UG-129, UG-130, UG-131, UG-132, UG-133, UG-134, UG-135, and UG-136 [18], A rupture disk may be used under a relief valve if good engineering practice is used to design the combined system, and there is a means of regularly checking for disk leakage by monitoring pressure in the space between the devices. See 18.4.1.1 in CGA G-2 [22]. A leaking disk shall be replaced because pressure downstream of the disk will prevent rupture at the desired pressure. Under no circumstances shall a rupture disk device be used as the sole, or as a supplemental, PRD on an ammonia container. The opening provided through the rupture disk, after burst, shall be sufficient to permit a flow rate at least equal to the capacity of the relief valve, and there is no interference with the proper functioning of the pressure relief valve.

5.8.1.2 Pressure relief valves shall be in direct communication with the vapor space of the container, unless a combina¬ tion rupture disk and relief valve are used. If a combination rupture disk is used, the rupture disk shall communi¬ cate with the vapoi space. Nonreclosing relief devices shall not be used as the sole means of protection.

5.8.1.3 The discharge from pressure relief valves shall be vented away from the container, upward and unobstructed to the atmosphere unless connected to a control device as defined in 5.8.1.4. All pressure relief valve discharge openings shall have suitable rain caps that will allow free discharge of the vapor and prevent the entrance of water. Provision shall be made for draining condensate that can accumulate.

5.8.1.4 When the discharge of ammonia from a pressure relief valve to the open air or atmosphere is impractical, or it is otherwise undesirable due to safety, health, or environmental considerations, pressure relief valve discharge may be routed to a properly designed, installed, Inspected, tested, and maintained control device such as an ammonia recovery unit, absorption unit, or flare system. This is only provided:

•

Flow capacity of the pressure relief valve is not reduced to less than the required rate;

•

Start-to-discharge pressure of the pressure relief valve is not changed from the setting marked on the pres¬ sure relief valve by its manufacturer or outside the range of settings specified in 5. 8.1.5;

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•

Backflow of any material from the control device to the discharge side of the pressure relief valve is pre¬ vented; and

•

Control device transmits no undue mechanical strain upon the pressure relief valve.

5.8.1.5 Container pressure relief valve shall be set to discharge at no more than 125% MAWP for containers built by the 1949 ASME Code Sections U-68 and U-69, and no more than 100% for those built by all subsequent ASME Codes [18], Set pressure tolerance is +10% to 0% for nonrefrigerated containers.

5.8.1.6 Pressure relief valves for excessive heat or fire protection used on containers covered by Sections 6, 11, and 12 shall be constructed to discharge at not less than the rates required in Appendix A before the pressure is in excess of 121% of the MAWP of the container. Relief protection for any other reason shall use ASME UG-125, UG-126, UG-127, UG-128, UG-129, UG-130, UG-131, UG-132, UG-133, UG-134, UG-135, and UG-136 [18],

5.8.1.7 Pressure relief valves shall be so arranged that the possibility of tampering will be minimized. If the pressure setting adjustment is external, the relief valves shall be provided with means for sealing the adjustment.

5.8.1.8 Shutoff valves shall not be installed between the pressure relief valves and the containers or systems covered by Sections 6,11, and 12 except that a shutoff valve may be used where the arrangement of the shutoff valve is such as always to afford the full capacity flow specified in 5.8.1.6 through a nonisolated pressure relief valve(s) that shall remain operative. NOTE—The previously mentioned exception is made to cover such cases as a three-way valve installed under two pressure relief valves, each of which has the required rate of discharge and is so installed as to allow either of the pressure relief valves to be closed off but does not allow both pressure relief valves to be closed off at the same time Another exception may be where two separate pressure relief valves are installed with individual shutoff valves. In this case, the two shutoff valve stems shall be mechanically interconnected in a manner that will allow full required flow of one pressure relief valve at all times Still another exception is a pressure relief valve manifold that allows one valve to be closed off with the remaining unblocked valve or valves providing not less than the rate of discharge shown on the manifold nameplate.

5.8.1.9 Each pressure relief valve used with systems covered by Sections 6, 11, and 12 shall be plainly and permanently marked as follows with:

•

letters "AA" or the symbol “NH3”;

•

pressure in psi at which the valve is set to start-to-discharge;

•

rate of discharge of the valve in ft3/min of air at 60 °F (15.6 °C) and atmospheric pressure;

•

month and year of manufacture; and

•

manufacturer’s name and model number.

For example, a pressure relief valve marked “AA250-4200 (air) 4/95” would mean that this valve is set to dis¬ charge at 250 psi (1724 kPa), 4200 ft3/min (120 m3/min) of air, and was manufactured in April 1995.

5.8.1.10 Piping or connections on either the upstream or downstream side shall not restrict the flow capacity of the relief valve.

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5.8.1.11 The manufacturer or supplier of a pressure relief valve manifold shall publish complete data showing the flow rating through the combined assembly of the manifold with pressure relief valves installed. The manifold flow rating shall be determined by testing the manifold with all but one valve discharging. If one or more openings have restrictions not present in the remaining openings, the restricted opening or openings, or those having the lowest flow, shall be used to establish the flow rate marked on the manifold nameplate. The marking shall be similar to that required in 5.8.1.9 for individual valves.

5.8.1.12 The discharge opening from any pressure relief valve shall not terminate inside any building or below the highest roof line of the building.

5.8.1.13 A pressure relief valve shall be subject to a systematic, periodic, visual external inspection at least annually to determine that it:

•

meets the applicable requirements specified in 5.8.1;

•

is free of evidence of tampering, damage, corrosion, or foreign matter that could prevent proper operation;

•

is free of leakage when subject to pressures less than the minimum allowable start-to-discharge setting;

•

has a properly installed rain cap or other device to avoid entry of moisture or other matter into the relief valve outlet; and

•

has an open weep hole to permit moisture to escape.

5.8.1.14 Any deficiency as can be found in 5.8.1.13 shall require immediate corrective action, replacement, or repair of the pressure relief valve as may be appropriate.

5.8.1.15 No pressure relief valve shall be used after the replacement date as specified by the manufacturer of the device. If no date is specified, a pressure relief valve shall be replaced no later than 5 years following the date of its manufacture or last repair unless it has first been disassembled, inspected, repaired, and tested by the manu¬ facturer, or by a National Board accredited valve repair organization so that the valve’s condition and performance is certified as being equivalent to the standards for the original valve. The data regarding repairs or reassembly shall be indicated by stamping the body or attaching a tag pertaining to the valve with the month and year to replace or recertify. Example: 4/01.

5.8.2

Hydrostatic relief valves

5.8.2.1 A hydrostatic relief valve or equivalent shall be installed in each section of piping (including hose) in which liquid ammonia can be isolated between_shutoff valves to relieve the pressure that could develop from the trapped liguid. If an eguivalent pressure relieving device is used, the maximum accumulative pressure possible within the system shall not exceed the limits of the svstem. A facility operating in the United States under 29 CFR 1910.119 Process Safety Management or in Canada, under the Canadian equivalent, may modify the requirement for a hydrostatic relief valve based on possibIe trapped line volume by technical analysis using methods and analysis in accordance with a recognized and generally accepted engineering approach [10] In no case shall the possible trapped volume of a line without hydrostatic relief valve protection exceed 26.4 gallons (100 liters).

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5.8.2.2 The discharge from hydrostatic relief valves shall be vented to a safe location The hydrostatic relief valve shall be protected from ingress of moisture, bugs, dirt, debris, etc. For example, a rain cap or other means that allows the hydrostatic relief valve to function properly.

5.8.2.3 Shutoff valves shall not be installed between a hydrostatic relief valve and the system it protects. To allow for maintenance of a hydrostatic relief valve while the system is in service, an isolation device may be installed provided that the piping circuit remains protected from overpressure. For example, a three-way valve with two hydrostatic relief valve installed in the valve that results in one hydrostatic relief valve always being in contact with the protected system may be used. 5.8.2.4 Each hydrostatic relief valve shall be plainly and permanently marked as follows with:

• letters "AA" or the symbol "NH/: •

pressure in psi at which the valve is set to start-to-discharge,

•

month and year of manufacture: and

•

manufacturer's name, symbol, or model number.

5.8.2.5 A hydrostatic relief valve shall be subject to a systematic, periodic, visual external inspection at least annually to determine that it:

•

meets the applicable reguirements specified in 5.8.2

•

is free of evidence of tampering, damage, corrosion, or foreign matter that could prevent proper operation:

•

is free of leakage when subiect to pressures less than the minimum allowable start-to-discharge setting; and

•

has a properly installed rain cap or other means to avoid entry of moisture or other matter into the relief valve outlet.

5.8.2.6 Any deficiency found in 5 8.2 5 shall reguire immediate corrective action, replacement, or repair of the hydrostatic relief valve as appropriate. If a hydrostatic relief valve activates it should be evaluated to determine suitability for continued use

5.8.2.7 No hydrostatic relief valve shall be used after the replacement date as specified by the manufacturer of the device. If no date is specified, a hydrostatic relief valve shall be replaced no later than 5 years following the date of its manufacture or last repair unless it has first been disassembled, inspected, repaired, and tested by the manufacturer, or by an accredited valve repair organization so that the valve’s condition and performance is certified as being eguivalent to the standards for the original valve The data regarding repairs or reassembly shall be indicated by stamping the body or attaching a tag pertaining to the valve with the month and year to replace or recertify. Example: 4/01

5.9

Filling densities

See 2.2.22 for a detailed definition of filling density.

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5.9.1

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CGA G-2.1—2023

Nonrefriqerated storage containers

5.9.1.1

Percent by weight

The maximum permitted filling density for ammonia in an uninsulated, aboveground, and nonrefriqeratecl storage container is 56% by weight.

5.9.1,2

Percent by volume

The maximum permitted filling density by volume as a percent of cm ilaii lei walei volume foi vaiious temperatures is summarized in Table 6. Table R —Maximum permitted filling volumes for nonrefriqerated storage containers

Temperature of liquid ammonia in tank °F °C (Any temperature) 20

-6.7

Maximum ammonia content as a % of container water volume

Uninsulated container

Insulated container

Underground container

81.9

83.4

84.8

86.2

87.7

89.2

30

-1.1

87.3

88.8

90.4

40

4.4

88.3

89.9

91.4

50

10 0

89.5

91.1

92.7

60

15.6

90.7

92.3

93.9

70

21 1

91.8

93.4

95.0

80

26.7

93.0

94.7

96.4

90

32.2

94.4

96 0

97 7

100

37.8

95.7

97.4

99.1

Example calculations at 60 °F;

•

Filling volume to density:

•

•

.

90.7% ( 907) liquid level x 1000 gal storage tank = 907 gal NHa (filling volume)

•

4662 lb

907 gal x 5,14 Ib/qal (NHa at 60 °F) = 4662 lb

8.33 Ib/qal (water at 60 °F) = 560 gal or 56% (filling density)

Filling density to volume:

• Maximum filling density of 56% (.56) x 1000 gal storage tank = 560 gal in a 1000 gal tank (filling density) •

560 gal x 8.33 Ib/gal (water at 60 °F) = 4664 lb

•

4664 lb

5.9.2

5.14 Ib/gal (NHa at 60 “F) = 907.4 gal or 90 7% (filling volume)

DOT containers

DOT Hazardous Materials Regulations (HMR) require that the liquid portion of the ammonia lading not completely fill an insulated tank car tank, portable tank, or cargo tank at 105 °F (41 °C); an uninsulated portable tank, cargo tank, single unit tank car tank, or multi-unit tank car tank at 115 °F (46 °C); or a cylinder at 130 °F (54 °C) [7], In the case of a tank car tank, the HMR require ullage for the liquefied gas of at least 2% of the total capacity of the tank at the reference temperature of 11 5 °F (46 °C) for a noninsulated tank and 1 05 °F (41 °C) for an insulated tank These filling limitations may be expressed in terms of a calculated maximum filling density designated by weight percentage. The term “filling density" for liquefied compressed gases is defined as the percent ratio of the weight of a liquefied compressed gas in a container or cylinder to the weight of water at 60 °F (1 5.6 °C) that the

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container or cylinder will hold. See 49 CFR 171.8; 173.24b; 173.304(a)(2) Table Note 1; 173.314(c) Table Notes 1,2,3, and 10; 173.315(a) Table Notes 1 and 5; and 173.315(c) [7].

5.9.3 If containers other than refrigerated containers are to be filled according to liquid level by any gauging method other than a fixed length dip tube gauge, each container should have a thermometer well and thermometer so that the internal liquid temperature can be easily determined and the amount of liquid and vapor in the container corrected to a 60 °F (15.6 °C) basis.

Transfer of ammonia

5.10

5.10.1 Anhydrous ammonia shall always be at a temperature suitable for the material of construction and design of the receiving containers. Certain steels are not suitable for refrigerated ammonia. See Appendix R of API 620, Design and Construction of Large, Welded, Low-Pressure Storage Tanks, for materials for low temper¬ ature service [45].

5.10.2 At least one qualified operator experienced in the procedures and trained in accordance with 3.1 shall monitor the transfer of ammonia from the time the connections are first made until they are finally disconnected. Such monitoring may be performed by a person on-site, from a remote location, or by electronic means. Capability shall be provided to halt the transfer in the event of an emergency.

5.10.3 Except for pneumatic pressure testing, containers may only be pressured with ammonia vapor. Upon discovery or subsequent to servicing, air or other system inerts shall be promptly purged from containers using accepted, documented practices. Industrial use process systems such as refrigerated storage systems, water treatment, pollution control, heat treatment, etc , may use inert gases such as nitrogen if adequate precautions are taken. Failure to remove air before returning to service can promote stress corrosion cracking of the pressure vessel.

5.10.4 Containers and cylinders shall be filled or used only upon the owner’s authorization.

5.10.5 If there is any opportunity for the release of ammonia during the process of gauging, purging, or charging (filling), containers and cylinders shall be in an open atmosphere or in a building provided for that purpose

—Gauging is understood to be a means for determining the liquid level of ammonia.

NOTE

5.10.6 Pumps used for transferring ammonia shall be recommended and labeled for ammonia service by the manufac¬ turer.

5.10.6.1 Positive displacement pumps shall be equipped with a pressure actuated bypass valve on the discharge side of the pump. This valve shall operate to limit the pressure developed by the pump to the maximum for which the pump is rated. Piping or tubing sized to carry the full capacity of the pump at the actuation pressure of this valve shall connect the discharge of this valve with the container from which ammonia is being pumped. If this line is capable of being closed off by a valve, an additional bypass device shall be incorporated in the pump to bypass back to the suction port. The pressure actuated bypass valve and the return piping or tubing shall be installed in accordance with the pump manufacturer’s recommendations.

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CGA G-2.1

5.10.6.2 On the discharge side of the pump, before the bypass valve line, install a pressure gauge graduated from 0 psi to -100 psi (0 kPa to 2760 kPa).

5.10.6.3 Plant piping shall contain shutoff valves located as close as practical to pump connections.

5.10.7 Compressors used for transferring or refrigerating ammonia shall be recommended and labeled for ammonia service by the manufacturer or certified for such service by the owner/operator using recognized and generally accepted good engineering methods.

5.10.7.1 Compressors, except those used for refrigeration, shall be designed for at least 250 psi (1724 kPa) working pressure. Crank cases of compressors should be vented to a safe location. Crank cases designed to hold pres¬ sure shall meet the requirements of 5.8.1.4, 5.8.1.8, 5.8.1.9, 5.8.1.10, 5.8.1.11, 5.8.1.12, 5.8.1.13, 5.8 1.14, and 5.8.1.15,

5.10.7.2 Plant piping shall contain shutoff valves located as close as practical to compressor connections.

5.10.7.3 A pressure relief valve large enough to discharge the full capacity of the compressor shall be connected to the discharge side before any shutoff valve. This pressure relief valve shall meet the requirements of 5 8.1 4, 5.8 1 8 5 8.1 9. 5.8.1.10, 5 8.1 11, 5 8 1 12, 5.8.1 13, 5 8.1 14, and 5.8.1.15.

5.10.7.4 Compressors shall have pressure gauges at suction and discharge graduated to at least 1 1/2 times the maxi¬ mum pressure that can be developed.

5.10.7.5 Adequate means such as a drainable liquid trap shall be provided on the compressor suction to minimize the entry of liquid into the compressor.

5.10.7.6

Where necessary to prevent contamination, an oil separator shall be provided on the discharge side of the com¬ pressor.

5.10.8 Container vapor and liquid piping, except for pressure relief valves and those specifically exempted in 5.5.5 and 5.5.6 shall be equipped with approved excess flow valves. Piping shall be designed to not restrict flow rates to the extent that protective devices will not function. Dedicated lines for loading and separate dedicated lines for unloading are recommended. Backpressure check valves should be considered where practical for filling con¬ nections.

5.10.8.1 All stationary storage installations with a water capacity greater than 4000 gal (15.1 m3) shall have approved emergency shutoff valve(s) or backflow check valves installed in the liquid and vapor fixed piping of the transfer system within 5 lineal ft (1.5 lineal m) or within reasonable distance of where the hose or swivel piping is attached

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to the fixed piping. This requirement does not apply to fixed piping feeding a process system. These emergency

shutoff valve(s) or backpressure check valves shall be protected from any possible pull-away-while-connected incident between the mobile container and the transfer station. As a result, any break resulting from a pull will occur on the hose or swivel-type piping side of the connection while retaining intact the valves and piping on the plant side of the connection. Protection from pull-away-while-connected incidents may be accomplished by:

•

reinforced concrete or reinforced-concrete and structural steel bulkheads or equivalent anchorage-strong enough not to break and massive enough not to be uprooted by the motor vehicle;

•

use of approved breakaway devices, specifically designed for this purpose; or

•

use of shear fittings designed to conform to good engineering practices.

Protection from pull-away-while-connected incidents is appropriate for all connections to mobile containers. In determining “reasonable distance,” protection for persons, property, and the environment shall be addressed. Such anchorage is not required for tank car unloading.

Approved emergency shutoff valve(s) shall incorporate a reliable actuation system that will close all of the emer¬ gency shutoff valve(s) of the piping system on the first attempt from a remote location in the event of emergency or testing.

5.10.9 Meters used for the measurement of liquid anhydrous ammonia shall be recommended and labeled for ammonia service by the manufacturer.

5.10.9.1 Liquid meters shall be designed for minimum working pressure of 250 psi (1724 kPa).

5.10.9.2 The metering system shall incorporate devices that will prevent the inadvertent measurement of vapor

5.10.10 This section applies to hose, piping, and fittings greater than 2 ft in length or greater than 3 in ID: ammonia should be vented to a safe location such as an adequate supply of water to a properly designed atmospheric discharge point, flare, etc.; and

(see 4.4.1).

•

Anhydrous

•

A water container used for venting anhydrous ammonia shall be properly designed to prevent the container from being overpressurized.

5.10.10.1

Each cargo tank motor vehicle unloading point at an anhydrous ammonia storage site shall have a valve for the purpose of venting ammonia installed in the piping at or near the point where the piping and hose from the cargo tank motor vehicle are connected.

5.10.10.2 The ammonia should be injected into the water as near the bottom of the vessel as practical See 4 4 1

5.10.10.3 Any agueous ammonia solution resulting posed of safely and properly.

from the venting process shall be reprocessed, recycled, used, or dis¬

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Liquid level gauging devices

5.11 5.11.1

Each container, except those filled by weight, shall be equipped with an approved liquid level gauging device.

5.11.2 Each container or system uoveied in Sections 6, 9, 10 (except cylinders), 11, and 12 shall be fitted with a liquid level gauge indicating the maximum level to which the container can be filled with liquid anhydrous ammonia at temperatures between 20 °F and 100 °F (-6.7 °C and 37.8 °C), except on containers provided with fixed maxi¬ mum level indicators such as fixed length dip tubes or containers that are filled by weight. Marks shall be in increments of not greater than 20 °F (-6.7 °C). See 5.9.3 regarding the requirement for thermometer well and thermometer.

5.11.3 Gauging devices that require bleeding of the product to the atmosphere such as the rotary tube, fixed tube, and slip tube devices, shall be designed so that the maximum opening of the bleed valve is not larger than No. 54 (0.055 in or 1.40 mm) drill size unless provided with an excess flow valve. This requirement does not apply to farm vehicles used for the application of ammonia as covered in Section 12.

5.11.4 Gauging devices shall have a design pressure equal to or greater than the design pressure of the container on which they are installed. 5.11.5 Fixed maximum liquid -level gauges shall be designed and installed to indicate a volumetric level not to exceed 85% of the container's water capacity. NOTE—This does not apply to refrigerated storage.

5.11.6 Gauge glasses of the columnar type shall be restricted to stationary nonrefrigerated storage installations. They shall be equipped with shutoff valves having metallic hand wheels, excess flow valves, and extra heavy glass adequately protected with a metal housing applied by the gauge manufacturer.

5.12

Painting of containers

Aboveground uninsulated containers should have a reflective surface maintained in good condition. White is recommended for painted surfaces but other colors having similar reflecting characteristics are acceptable.

—

NOTE Caution should be exercised to ensure that graphic designs, company logos, etc., do not significantly reduce the necessary reflective characteristics of the container surface.

5.13

Electrical equipment and wiring

Electrical equipment and wiring for use in ammonia installations shall be general purpose or weather resistant as appropriate. Where uuiiuei illations of ammonia In air In excess of 16% by volume are expected to be present during normal operations, electrical equipment and wiring shall be installed to comply with the requirements specified for use in hazardous locations, Class I, Group D of NFPA 70, National Electrical Code®, Articles 500 and 501 [46].

CGA G-2.1—2023

5.14

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Heating devices for containers and cylinders

Anhydrous ammonia containers and cylinders shall not be heated if the contents are greater than the maximum allowed filling density. If the contents are equal to or less than the maximum allowed filling density, ammonia containers or cylinders may be heated subject to the following conditions. Average surface temperature in the heated area on the vessel shall not exceed the saturation temperature of ammonia at 80% of the vessel MAWP and relief valve setting. The resulting limits are shown in Table 7. Table 7—Ammonia container maximum heating limits Vessel MAWP, or relief valve setting, whichever is less

80% of MAWP

Allowable surface temperature of heated container

250 psi (1724 kPa)

200 psi (1379 kPa)

101 °F (38 °C)

285 psi (1965 kPa)

228 psi (1572 kPa)

109 °F (43 °C)

300 psi (2068 kPa)

240 psi (1655 kPa)

112 °F (44 °C)

315 psi (2072 kPa)

252 psi (1737 kPa)

115 °F (46 °C)

366 psi (2523 kPa)

293 psi (2020 kPa)

125 °F (52 °C)

The heating device or system shall:

•

be designed to be fail-safe;

•

be listed by a recognized testing laboratory or meet recognized and generally accepted good engineering practices (RAGAGEP) for the design of electrical heating eguipment;

•

conform to all applicable mechanical and electrical codes in the jurisdiction where applied; and

•

be approved by the manufacturer as suitable for use in heating of the specific type and size of anhydrous ammonia container(s).

6

Systems using stationary, pier-mounted or skid-mounted, aboveground or underground, nonrefrigerated storage

This section applies to stationary, pier-mounted, skid-mounted, aboveground or underground, nonrefrigerated storage installations using containers other than those constructed in accordance with DOT specifications. Sec¬ tion 5 applies to this section unless otherwise noted.

Design pressure and construction of containers

6.1

The minimum design pressure for nonrefrigerated containers shall be 250 psi (1724 kPa). See 5.1 2 and 5.2. NOTE—Existing U-68 and U-69 ASME Code containers with a design pressure of 200 psi (1379 kPa) are acceptable for reinstallation if recertified to 250 psi (1724 kPa) in accordance with NBIC procedures and if approved by the local AHJ [18. 19]

Container valves and accessories and discharge connections

6.2 6.2.1

The minimum protection for all vapor and liquid connections, except for pressure relief valves and those specifi¬ cally exempted in 5.5.5 and 5.5.6, shall be one of the following:

•

internal valve

in

the tank opening with a manual shutoff valve located immediately outside of the opening:

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CGA G-2.1—2023

approved excess flow valve in the tank opening with a manual shutoff valve located immediately outside of the opening, or backpressure check valve in the tank opening with a manual shutoff valve located immediately outside of

the opening. The installation shall be made so that any undue strain beyond the excess flow or backpressure check valve shall not cause breakage between the valve and the container.

6.2.2 In addition to the minimum protection, installation of emergency shutoff valves may be considered. This can be accomplished by either actuation of an internal valve or the addition of a separate emergency shutoff valve located within 10 lineal fl (3 lineal m) of the opening side of the manual shutoff valve. If an emergency shutoff valve is installed, the following reguirements shall be met:

•

Approved emergency shutoff valves or internal valves shall incorporate a reliable actuation system (for ex¬ ample, electrical, pressure, or cable) that closes all of the emergency shutoff valves or internal valves of the piping system on the first attempt in the event of emergency or of testing from a remote location. There shall be a minimum of two remote actuation locations reasonably opposite to each other; and

•

If using a pressure source for activation of the emergency shutoff valves or internal valves, nitrogen, com¬ pressed air, or carbon dioxide is deemed acceptable If using compressed air as a pressure source, the air shall be clean and kept at a moisture level that does not prevent the system from operating. Propane or other flammable materials shall be prohibited for use to activate an emergency shutoff valve or an internal valve.

Actuation systems should be tested annually for the functions required

6.2.3 Each storage container shall be provided with a pressure gauge graduated from 0 psi to 400 psi (0 kPa to 2760 kPa). Gauges shall be designated for use in ammonia service.

6.2.4 All containers shall be equipped with a suitable vapor equalizing connection

6.2.5 All containers shall be equipped with a fixed maximum liquid level gauge.

Pressure relief valves

6.3 6.3.1

Every container shall be provided with one or more pressure relief valves of spring-loaded or equivalent type that shall comply with the following specifications:

•

Relief valves shall be installed in a manifold or other suitable device so that they can be replaced while the container remains pressurized. See 5. 8.1.8 NOTE;

•

The discharge from pressure relief valves shall be vented away from the container, upward and unobstructed to the open air to an area so persons, property, and the environment will not be harmed. Vent pipes shall not be restrictive or smaller in size than the pressure relief valve outlet connection. All pressure relief valves shall have suitable rain caps that will allow free discharge of the vapor and prevent the entrance of water. Suitable provision shall be made for draining condensate that can accumulate; and

•

If desired, vent pipes from two or more pressure relief valves located on the same unit, or similar lines from one or more different units, may be run into a common header, provided the cross-sectional area of such header is at least equal to the sum of the cross-sectional areas of the individual vent pipes.

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6.3.2 The rate of discharge of spring-loaded pressure relief valves installed on underground containers may be reduced by not more than 30% of the rate of discharge specified in Appendix A. Containers so protected shall not be uncovered after installation until the liquid ammonia has been removed. Containers that may contain liquid am¬ monia before being installed underground and before being completely covered with earth are to be considered aboveground containers when determining the rate of discharge requirements of the pressure relief valves.

6.3.3 On underground installations where there is a probability of the manhole or housing becoming flooded, the dis¬ charge from vent lines shall be located above the high water level. Ail manholes or housings shall be provided with ventilated louvers, or their equivalent that discharge their content into the manhole housing. The area of such openings shall equal or exceed the combined discharge areas of the pressure relief valves and vent lines.

Installation of storage containers

6.4 6.4.1

Containers installed aboveground shall be provided with substantial reinforced concrete footings and foundations or structural steel supports mounted on reinforced concrete foundations. In either case, the reinforced concrete foundations or footings shall extend below the established frost line and shall be of sufficient width and thickness to support the total weight of the containers and contents adequately. Where required by local codes, seismic loads shall be considered in the design of the footings and foundations. The foundation shall maintain the lowest point of the tank not less than 18 in (0.46 m) above the ground. Floating type foundations shall also be acceptable providing the foundations are designed to adequately support the tank, contents, and piping. See 5.6.

6.4.2

Horizontal aboveground containers .shall be mounted on foundations to permit expansion and contraction. Every container shall be supported to prevent the concentration of excessive loads. If supports of the saddle type are employed, the bearing afforded by the saddles should extend over at least one third (1/3) of the circumference of the shell. Suitable means for preventing corrosion shall be provided on that portion of the container in contact with the foundations or saddles. 6.4.3 Secure anchorage or adequate pier height shall be provided against container flotation wherever high flood water can occur.

6.4.4 The location and installation of an underground container and the type of corrosion control employed shall have approval of the appropriate AHJ. Containers buried underground shall be placed so the top of the container is at least 1 ft (0.3 m) below the surface. Should ground conditions make compliance with these requirements imprac¬ tical, precautions shall be taken to prevent physical damage to the container. It is not necessary to cover the portion of the container to which a manhole and other connections are affixed. When necessary to prevent float¬ ing, containers shall be securely anchored or weighted.

6.4.5 As a minimum, underground containers shall be set on firm foundations (firm earth may be used) and be sur¬ rounded by at least 6 in of noncorrosive, inert materials such as soft earth, sand, or gravel well compacted into place. As a further means of resisting corrosion, the container and its piping, before placement in the ground, shall be provided with all of the following:

•

Suitable protective coating applied after proper surface preparation in accordance with the coating manufac¬ turer’s recommendations;

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Cathodic protection; and

Electrical isolation of the container from ancillary equipment.

Corrosion-resistant materials of construction may be used as an option. A container that has been coated shall be lowered into place to prevent abiasiun ui damage to the coaling. Selection of the type of protection should be based upon the judgment of a qualified engineer having knowledge of the corrosion history of the area.

6.4.6 The horizontal distance between aboveground and underground containers of over 1200 gal (4.5 m3) capacity shall be at least 5 ft (1.5 m).

6.4.7 A groundwater monitoring program meeting local, state, or federal regulatory requirements shall be established at the storage site by the owner of the underground storage system.

6.4.8 Underground tanks pose additional requirements for owners and operators. These include installation and maintenance requirements, regulatory notifications, and financial responsibilities. The appropriate AHJ should be consulted. See 40 CFR Part 280 [23],

6.5

Reinstallation of containers

6.5.1 Containers once installed underground shall not later-be reinstalled aboveground or underground unless they successfully withstand hydrostatic pressure retests at the pressure specified for the original hydrostatic test as required by the ASME Code under which the tank was constructed. It shall also show no evidence of serious corrosion [18].

6.5.2

Where containers are reinstalled underground, the corrosion protection shall meet the requirements of 6.4.5. Where containers are reinstalled aboveground, PRDs, or gauging devices shall comply with 5.8, 5.11, and 6.3 as applicable to aboveground containers.

6.6

Marking containers

6.6.1 Each container or group of containers shall be marked on at least two sides, which are visible with the words, ANHYDROUS AMMONIA, or CAUTION—AMMONIA, in sharply contrasting colors with letters not less than 3.9 in (100 mm) high.

6.6.2 Each container or group of containers shall be conspicuously marked with a hazard warning label complying with 29 CFR 1910.1200 [11],

6.6.3 Each container or group of containers that are installed underground shall have a sign bearing marks and labeling as required in 6.6.1 and 6.6.2 located adjacent to the cover described in 6.7.2.

CGA G-2.1—2023

COMPRESSED GAS ASSOCIATION, INC.

PAGE 39

Protection of container and appurtenances

6.7 6.7.1

Containers and appurtenances shall be located or protected by suitable barriers to avoid damage by trucks or other vehicles.

Shutoff valves on storage tank openings shall be kept closed and protected by suitable means against tampering or theft of product when the installation is unattended. Examples of suitable means could include valve locks, remote surveillance, security systems, fencing, lighting, motion detectors, alarms, or chemical additives that ren¬ der the anhydrous ammonia unusable or undesirable for illicit use. One means of protection is usually not ade¬ quate and multiple means of protection may be needed. Regarding site security, see federal agencies cited in 3.3.4.1 as well as referenced contact information in Section 13.

6.7.2 All connections to underground containers should be located within a suitable dome, housing, or manhole fitted with a substantial removable cover.

6.7.3 Storage containers need not be electrically grounded.

Identification for emergency

6.8

A legible sign shall be displayed on the premises at which a storage system is located, so as to be readily visible to emergency response personnel, with lettering not less than 2 inches in height, stating the following:

.

phrase "EMERGENCY INFORMATION”;

•

name of facility;

•

name or title of at least two responsible persons;

•

area code and telephone number(s) of each person listed; and

•

phrase, "the 911 address is”, and the appropriate 911 address.

7

Refrigerated storage

This section applies specifically to systems using tanks for the storage of anhydrous ammonia under refrigerated conditions. Section 5 applies to this section unless otherwise noted.

7.1

Design of tanks

7.1.1 Tanks may be designed for any storage pressure desired as determined by economical design of the refrigerated system.

7.1.2 The design temperature shall be the minimum temperature to which the container will be refrigerated and shall be so designated.

7.1.3 Containers with a design pressure exceeding 15 psi (103 kPa) shall be constructed in accordance with 5.2.

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CGA G-2.1—2023

7.1.4 Tanks with a design pressure of 15 psi (103 kPa) or less shall be constructed in accordance with the general requirements of API 620, including Appendix R [45].

7.1.5 When austenitic stainless steals or nonferrous metals are used, the ASME Code shall be used as a guide in selection of materials for use at the design temperature [18].

7.2

Installation of storage tanks (aboveground)

7.2.1 Tanks shall be supported on suitable noncombustible foundations designed to accommodate the type of tank being used.

7.2.2 Adequate protection against flotation or other water damage shall be provided wherever high flood water might occur.

7.2.3 Tanks storing product that is less than 32 °F (0 °C) shall be supported to prevent the effects of freezing and subsequent frost heaving of the soil, otherwise heat shall be supplied.

7.2.4 The area surrounding a refrigerated tank, or group of such tanks, shall be provided with drainage, diked, or provided with other secondary containment systems to prevent accidental discharge of liquid from spreading to uncontrolled areas.

7.2.5 When drainage is employed, a slope of not less than 1% shall be provided. The drainage system shall terminate in an impounding basin having a capacity as large as the largest tank served. 7.2.6

Provision shall be made for the drainage of rain water from the dike or impounding area. Such drainage shall be provided with a positive means to stop the flow.

7.2.7 Where a dike is employed, the capacity of the diked enclosure shall be 110% of the capacity of the largest tank served When computing the volume of the dike, allowance shall be made for the volume displaced by all other containers in the diked area.

7.2.8 The walls of a diked enclosure or the wall of an impounding basin used in a drainage system shall be of earth, steel, concrete, or other suitable material designed to be liquid tight and to withstand the hydrostatic pressure and temperature. Earth walls shall have a flat top at least 2 ft (0.6 m) wide. The slope shall be stable and con¬ sistent with the angle of repose of the earth used. 7.2.9

The ground in an impounding basin or within a diked enclosure should be graded so that small spills or the early part of a large spill will accumulate at one side or corner, thereby contacting only a relatively small area of ground

CGA G-2.1—2023

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and exposing a relatively small surface area for heat gain. Shallow channels in the ground surface or low curbs of earth can help guide the liquid to these low areas without contacting a large ground area.

Marking refrigerated containers

7.3 7.3.1

Each refrigerated container shall be marked with a nameplate on the outer covering in an accessible place as specified in the following:

•

name and address of the builder and the date of fabrication;

• •

maximum volume or weight of the product, whichever is most meaningful to the user;

•

minimum temperature in degrees Fahrenheit (°F) or degrees Celsius (°C) for which the container was de¬ signed;

•

maximum allowable water level to which the container may be filled for the test purposes;

•

density of the product in pounds per cubic foot (lb/ft3) or kilograms per cubic meter (kg/m3) for which the container was designed; and

•

maximum level to which the container may be filled with liquid anhydrous ammonia.

design pressure;

7.3.2 Each refrigerated container shall be marked on two directly opposite sides at near eye level with the words, ANHYDROUS AMMONIA, in sharply contrasting colors with letters not less than 3.9-in (100 mm) high.

7.3.3 Each refrigerated container shall be conspicuously marked with a hazard warning label complying with 29 CFR 1910.1200 [10],

Tank valves, accessories, fill pipes, and discharge pipes

7.4

7.4.1 Shutoff valves shall be:

•

provided for all connections except those with a No. 54 (0.055 in or 1.40 mm) drill size restriction, plugs, pressure relief valves, and thermometer wells; and

•

located as close to the tank as practical.

7.4.2 A check valve shall be installed on the tank liquid fill connection if it is located below the maximum liquid level. A remotely operated shutoff valve shall be installed on other connections located below the maximum liquid level. See 5.10.8.

7.4.3 Each refrigerated container shall be equipped with an approved liquid level gauging device and high liquid level alarm.

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7.5

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CGA G-2.1 2023

Pressure relief valves

7.5.1

The tank shall be provided with a pressure relief system of one or more pressure relief valves that can limit the tank pressure to less than 115% (110% it only one pressure relief valve is used) of the design pressure during abnormal operating conditions other than fire and to less than 121% of the design pressure during abnormal operating conditions that include fire. One of the pressure reliof valves shall be set to start-to-discharge al a pressure not in excess of the design pressure of the tank, and all other pressure relief valves needed to limit the tank pressure to less than 1 15% (110% if only one pressure relief valve is used) of the design pressure during abnormal operating conditions other than fire shall be set to discharge at a pressure not in excess of 105% of the design pressure. All additional pressure relief valves needed to limit the tank pressure to less than 121% of the design pressure during abnormal operating conditions including fire shall be sei lo slarl-lo-discharge at a pressure not in excess of 110% of the design pressure. 7.5.1.1 Abnormal operating conditions considered shall include any or any plausible combination of:

•

Utility failure (power, cooling water, instrument air, etc.);

•

Mechanical failure (instrument, compressor, valve, control valve, insulation, etc.);

•

Excessive pumping rates into the tank (compressed vapor space);

•

Excessive temperature of ammonia liquid pumped into the tank below the liquid level (possible delayed flashing or rollover);

•

Inadvertent breakthrough of gas or liquid from manufacturing or other related operations;

•

Changing atmospheric conditions (ambient temperature, barometric pressure, wind, etc.);

•

Fire (pool fire from flammable liquid, radiant effects from nearby fires, burning insulation, etc.)4; and

•

Any other conditions or possible combination of conditions that could cause the pressure of the tank to ex¬ ceed the design pressure.

Refrigerated ammonia tank installations shall be evaluated for risk of exposure to all applicable fire scenarios. Ammonia liquid leaked from the refrigerated tank in outdoor installations generally should not be considered a fire risk, see 1.3.4. In cases where flammable liquids or materials are present (or can be present) in quantities capable of sustaining a fire, use the appropriate industry standards that apply to storage tanks exposed to hy¬ drocarbon fires.

7.5.1.2 Calculations of the required relief capacity for abnormal operating conditions shall consider the storage tank is filled to maximum level and already at steady-state conditions for maximum tank pressure when the event caus¬ ing overpressure occurs

7.5.1.3 Documentation shall be kept on-site to show that the conditions listed in 7.5.1.1 were considered in determining the relief requirements, expressed in standard cubic feet per minute (scfm), for each tank installation. At a mini¬ mum, each facility shall document, for each tank installation, the following:

•

design pressure of each tank;

•

abnormal conditions that are applicable to the tank;

4 See API 2000, Venting Atmospheric and Low-pressure Storage Tanks—Nonrefrigerated and Refrigerated for pool fire effects from flammable products that might surround the tank from adjacent operations [47],

—2023

CGA G-2.1

COMPRESSED Gas ASSOCIATION. INC-

PAGE 43

•

required relieving rate imposed by the applicable abnormal conditions (also include any scenarios that in¬ clude combined rates from simultaneously occurring abnormal conditions, if applicable);

•

rationale for why deselected listed abnormal conditions are not applicable;

• design flow rate used to for the tank's relief valve capacity (this should be the largest single or combined rate from among the applicable conditions);

•

list of relief device(s) installed on the tank, their pressure setpoints, and their relief capacities;

•

manufacturer's data for each relief device demonstrating the design conditions and relief capacities; and

•

most recent relief device inspection and repair report(s).

7.5.2 Shutoff valves of adequate flow capacity may be provided and used to facilitate inspection and repair of pressure relief valves. When a shutoff valve is provided, it shall be so arranged that it can be locked or sealed open and it shall not be closed except by an authorized person who shall remain stationed there while the valve remains closed and who shall again lock or seal the valve open when leaving the station.

7.5.3 Pressure relief valves shall comply with the following

•

If stacks are used, they shall be suitably designed to prevent obstruction by rain, snow, ice, or condensate. The outlet size shall not be smaller than the nominal size of the pressure relief valve outlet connection;

•

Discharge lines may be used, if desired. Multiple pressure relief valves on the same storage container may be run into a common discharge header. The backpressure created by the discharge line and header shall fall within the container pressure relief and set discharge levels/limits/ranges stated in 7.5.1. No other con¬ tainer or system shall exhaust into this discharge line or header. The vent lines shall be installed to prevent accumulation of liquid in the lines; and

•

The discharge from pressure relief valves shall be vented away from the container, upward and unobstructed to the open air to an area so persons, property, and the environment will not be harmed. All pressure relief valves shall have suitable rain caps that will allow free discharge of the vapor and prevent the entrance of water. Suitable provision shall be made for draining condensate that can accumulate.

7.5.4 Atmospheric storage shall be provided with vacuum breakers of adequate capacity to respond to anticipated rates of liquid withdrawal and to rapid atmospheric changes to avoid damage to the container. Ammonia gas may be used to provide a pad.

7.5.5 Pressure relief valves used to protect other systems at refrigerated storage installations shall discharge to the open air unless connected to a control device as defined in 5.8.1.4.

7.5.6 Because emergency venting for a double-wall refrigerated storage tank is complex, no calculation method is presented here. A thorough analysis of the fire relief for a double-wall refrigerated storage tank should be con¬

ducted. 7.6

Protection of containers and appurtenances

Refrigerated storage containers and appurtenances shall comply with 6.7

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7.7

CGA G-2.1—2023

Reinstallation of containers

Containers of such size as to require a field fabrication shall, when moved and reinstalled, be reconstructed and re-inspected in complete accordance with the original requirements under which they were constructed. The containers shall be subjected to a pressure retest, and if rerating is necessary, it shall be done in accordance with the applicable pressure of the original requirements.

7.8

Refrigeration load and equipment

7.8.1 The total refrigeration load shall be computed as the sum of the following

7.8.1.1 Load imposed by heat flow into the container caused by the temperature differential between the ambient tem¬ perature and the storage temperature;

7.8.1.2 Load imposed by heat flow into the tank caused by maximum sun radiation; and

7.8.1.3 Maximum load imposed by filling the tank with ammonia warmer than the design storage temperature.

7.8.2 More than one storage tank may be handled by the same refrigeration system.

7.8.3

Compressors

See also 5.10.7.

7. 8.3.1 A minimum of two compressors shall be provided, either of which is of sufficient size to handle the loads listed in 7.8.1.1 and 7.8.1.2, except as provided in 7.8.3.3. Where more than two compressors are provided, minimum standby equipment equal to the largest normally operating equipment shall be installed. Compressors required for 7.8.1.3 may be used as standby equipment for compressors required in 7.8.1.1 and 7.8.1.2.

7.8.3.2 Compressors shall be sized to operate with a suction pressure at least 10% below the minimum setting of the pressure relief valve(s) on the storage tank and shall withstand a suction pressure at least equal to 121% of the design pressure of the tank. Discharge pressure will be governed by condensing conditions.

7. 8.3.3 Where facilities are provided to safely dispose of vented vapor to an automatic flare or to a process unit, a single compressor of sufficient size to handle the load listed in 7.8.1.1 and 7.8.1.2 shall be allowed. 7.8.4

Compressor drives

Each compressor shall have its own drive unit. Any standard drive consistent with good design may be used.

CGA G-2.1—2023

COMPRESSED GAS ASSOCIATION, INC.

PAGE 45

An emergency source of power of sufficient capacity to handle the loads listed in 7.8.1.1 and 7.8.1.2 shall be provided unless facilities are provided to safely dispose of vented vapors while the refrigeration system is not operating.

7.8.5

Automatic control equipment

7.8.5.1 The refrigeration system shall be arranged with suitable controls to govern the compressor operation in accord¬ ance with the load as evidenced by the pressure in the container(s).

7.8.5.2 An emergency alarm system shall be installed to function if the pressure in the container(s) rises to the maximum or falls to the minimum allowable operating pressure.

7.8.5.3 An emergency alarm and shutoff shall be located in the condenser system to respond to excess discharge pres¬ sure caused by failure of the cooling medium.

7.8.5.4 All automatic controls shall be installed to preclude operation of alternate compressors unless the controls will function with the alternate compressors.

7.8.6 7.8.6.1

Separators

_-

An entrainment separator of suitable size and design pressure shall be installed in the compressor suction line. The separator shall be designed for the MAWP of the system in which it is installed. The separator shall be equipped with a drain and gauging device. A maximum liquid level control with alarm should be installed.

7.8.6.2 An oil separator of suitable size shall be installed in the compressor discharge line. It shall be designed for at least 250 psi (1724 kPa) and shall be equipped with a gauging device and drain valve. A maximum oil level control with alarm should be installed.

7.8.6.3 A separator shall be equipped with a pressure relief valve if the separator can be isolated with shutoff valves.

7.8.7

Condensers

The condenser system may be cooled by air or water or both. The condenser shall be designed for at least 250 psi (1724 kPa). Provision shall be made for purging noncondensibles either manually or automatically. The condenser shall be equipped with a pressure relief valve if the condenser can be isolated with shutoff valves.

7.8.8

Receiver and liquid drain

A condenser effluent receiver shall be provided that is equipped with automatic level controls and valving de¬ signed to discharge the liquid ammonia to storage, or with a high pressure liquid drain trap of suitable capacity. The receiver shall be designed for at least 250 psi (1724 kPa) operating pressure and be equipped with the necessary connections, pressure relief valves, and gauging device.

Page 46

7.8.9

Compressed Gas Association, Inc.

—2023

CGA G-2.1

Insulation

Refrigerated containers and pipeline that are insulated shall be covered with a material of suitable quality and thickness for the temperatures encountered. Insulation shall be suitably supported and protected against the weather. Weatherproofing and insulation shall be of a type that will not support flame propagation and will not cause corrosion when wet.

Safety equipment

7.9

Each refrigerated storage installation shall have on hand the minimum safety equipment required in 3.4.

7.1 0

Identification for emergency

A legible sign shall be displayed on the premises at which a refrigerated storage system is located to be readily visible to emergency response peisonnel slating the name, address, and telephone number of the nearest rep¬ resentative, agent, or owner of the storage system.

8

Systems mounted on railcar structures (tank cars), other than DOT class 106A, for transportation of ammonia

This section applies specifically to systems using DOT single-unit pressure tank car tanks mounted on railcar structures and used for the rail transportation of ammonia. In addition to complying with the requirements of these standards, systems for tank cars transporting ammonia shall comply, where required, with the requirements of DOT and shall also be approved by the Association of American Railroads (AAR).

8.1

Design and construction

Tank car tanks and tank cars shall be designed, constructed, and tested in compliance with current DOT speci¬ fications as are applicable and shall receive approval from the AAR Committee on Tank Cars before being placed into service. 8.2

Pressure relief valves

Tank cars shall be provided with a pressure relief valve as required by DOT regulations.

Pressure relief valves used on tank cars shall be inspected, repaired, or replaced in accordance with applicable DOT regulations [7]. 8.3

Marking and placarding

8.3.1 Each tank car transporting ammonia or ammonia residue shall be marked with the proper shipping name, and the words INHALATION HAZARD on two opposing sides of the tank car, except that bulk packages marked before October 1, 1991, need not be remarked AMMONIA, ANHYDROUS, LIQUEFIED if the tank car otherwise complies with the provisions of 49 CFR 172.302 [7], Markings shall be at least 3.9 in (100 mm) in height and shall have a width ot at least 0.24 in (6.1 mm). The markings shall be displayed on a background of sharply contrasting color on both sides of the tank car and near the stenciled DOT specifications markings. Each tank car shall also be marked, or displayed either on an orange panel or on a placard per the provisions of 49 CFR 172.332, with the UN identification number, 1005, on each side and each end so as required by DOT regulations. See 49 CFR 172.302 [7],

8.3.2 Each tank car transporting ammonia shall be provided with placarding on each side and each end in accordance with DOT regulations [7].

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8.3,3

Each tank car transporting ammonia shall be marked with a hazard warning label complying with 29 CFR 1910.1200 unless such label is provided with the shipping document for the tank car conforming with 49 CFR Part 172, Subpart C as appropriate [11, 7],

Tank car loading and unloading locations and operations

8.4 8.4.1

The loading, unloading, and shipping of tank cars shall conform to the requirements of DOT regulations [7],

8.4.2 Anhydrous ammonia tank cars shall be loaded and unloaded only at locations approved by the AHJ(s) and meet¬ ing the requirements of 3.4 and 5.10.1 through and including 5.10.9.2. Approved rail car loading and unloading locations, other than permanent facilities shall:

• • •

notify first responders of location, duration, and times of operation;

maintain a minimum of two qualified people present during transfer of ammonia; and post emergency information in accordance with 6.8

8.4.3 Loading and unloading operations shall be performed by qualified personnel meeting the requirements of 3.1, properly trained in the procedures involved, and made responsible for compliance with such procedures.

8.4.4 Rail track at tank car loading and unloading positions shall be essentially level.

8.4.5 Brakes shall be set and the wheels blocked in both directions on all tank cars being loaded or unloaded

8.4.6 Caution signs shall be so placed on the track or car to give necessary warning to persons approaching the car from the open end or ends of the siding. The signs shall be of metal or other comparable material at least 12 in (300 mm) high by 15 in (380 mm) wide in size, and bear the words, STOP - TANK CAR CONNECTED, or STOP - MEN AT WORK, the word, STOP being in letters at least 4 in (100 mm) high. Other words should be in letters at least 2 in (50 mm) high. The letters shall be white on blue background. A car so protected shall not be coupled or moved The signs shall remain in place until the tank car valves have been closed and the transfer lines have been disconnected.

8.4.7 A standard derail shall be properly set and secured in the derailing position between the car being loaded or unloaded and other cars being moved on the same track.

8.4.8 A tank car shall not be loaded or shipped unless it meets DOT specifications for the shipment of ammonia.

8.4.9 A tank car that has been loaded shall not be shipped unless it has been loaded by, or with the consent of, the tank car owner or owner’s agent.

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8.4.10 A tank car used to transport a commodity other than ammonia shall be purged completely of the previous com¬ modity before being loaded with ammonia. Markings and placarding shall be changed accordingly.

8.4.11 Before connecting loading lines to a tank car and/or before releasing a tank car to the carrier, a visual inspection for obvious defects should be made for the following conditions:

•

Determine whether the tank car undercarriage, safety appliances (handrails, grab irons, etc.), walk surfaces, ladders, steps, air and hand brake systems, trucks, head shields, and couplers appear to be in a safe con¬ dition;

•

Determine if the tank car tank and pressure relief valve periodic retest dates are current;

•

Determine if the tank car tank, or jacket if the tank is insulated, shows evidence of abrasion, dents, gouges, severe corrosion, or other damage; and

•

Determine whether manway bolts and gaskets, external valves, pressure relief valves, gauges, and fittings appear to be in serviceable condition and free of leakage.

8.4.12 If leakage occurs at any manway, valve, gauge, gasket, or fitting during loading, the loading shall stop and the cause of the leak corrected before loading can be resumed. If necessary to effect leak repairs, the tank car shall be emptied and repairs made at the loading terminal or a qualified repair facility.

8.4.13 A damaged or defective tank car shall be forwarded to a carrier repair track or to a qualified repair shop before it is returned to service. Structural repairs to a tank car, including welding repairs on the tank car tank, shall be performed only at a repair facility authorized by the AAR and by a qualified welder following authorized proce¬ dures.

8.4.14 An ammonia tank car shall be consigned for delivery and unloaded on a private track. State and local regulations regarding unloading operations shall be observed.

8.4.15 If a private track is unavailable, an ammonia tank car equipped with excess flow valves may be consigned for delivery and unloaded on a carrier track, provided it is unloaded into permanent storage of sufficient capacity to receive the entire contents of the car.

8.4.16 After loading or unloading a tank car, all valves shall be closed and transfer linos disconnected. Caps or plugs on tank car sample valves, liquid valves, vapor valves, and gauging device valves shall be replaced and made wrench-tight. Gauging devices shall be secured and gauge housings screwed in place. Protective housing covers shall be secured, pinned, and proper seals put in place when required. Leaks from any source on a tank car shall be stopped before a car may be released to the carrier.

9

Systems mounted on trucks, semitrailers, and trailers for transportation of ammonia

This section applies specifically to systems mounted on trucks, semitrailers, and trailers (other than those cov¬ ered under Sections 10, 11, and 12) used for the transportation of ammonia. Section 5 applies to this section unless otherwise noted.

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Systems for trucks and trailers for transportation of anhydrous ammonia, in addition to complying with the re¬ quirements of these standards, shall also comply, where required, with the requirements of DOT and those of any other regulatory body that may apply.

9.1

Design pressure of containers

9.1.1 Containers used in interstate commerce shall be designed and constructed in accordance with the ASME Code, have a minimum design pressure of 265 psi (1827 kPa), and meet other applicable requirements of DOT regu¬ lations. Containers designed and constructed in accordance with earlier ASME Code editions having a minimum design pressure of 250 psi (1724 kPa) and meeting certain limiting conditions as required by DOT regulations, are authorized for use in intrastate commerce [18, 7],

9.1.2 The shell or head thickness of any container shall not be less than 0.1875 in (4.8 mm)

9.1.3 All container openings, except pressure relief valves, liquid level gauging devices, and pressure gauges, shall be labeled to designate whether they communicate with liquid or vapor space with the container filled to the maximum permitted filling density. Labels shall be readily visible and may be on or adjacent to the valves closing the openings.

9.1.4 Baffles are not required for cargo tanks

9.2

Container mounting

9.2.1 The means of attachment of any container to the cradle, frame, or chassis of a vehicle shall be designed on a basis of 2 “g” loading in either direction, using a safety factor of not less than 4, based on the ultimate strength of the material used. For the purpose of this requirement, 2 “g” of load support is equivalent to three times the static weight of the articles supported; 2 "g” of loading and bending, acceleration, and torsion is equivalent to twice the static weight support applied horizontally at the road surface.

9.2.2 “Hold-down” devices, when used, shall anchor the container to the cradle, frame, or chassis in a suitable and safe manner that will not introduce undue concentration of stresses. These devices shall incorporate positive means for drawing the container down tight and suitable stops or anchors shall be provided to prevent relative movement between the container and framing due to stopping, starting, or changes in direction.

9.2.3 Vehicles designed and constructed so that the cargo tanks constitute, in whole or in part, the stress member used in lieu of the frame, shall be supported by external cradles subtending at least 120 degrees of the shell circumference. The design calculation shall include beam stress, shear stress, torsion stress, bending moment, and acceleration stress, in addition to those covered by the code under which the cargo tank was designed.

9.2.4 If a liquid withdrawal line is installed in the bottom of a container, the connections thereto, including hose, shall not be lower than the lowest horizontal edge of the motor vehicle axle.

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9.2.5 Provision shall be made to secure both ends of the hose while in transit. 9.2.6

When the cradle and the container are not welded together, suitable material shall be used between them to reduce abrasion.

9.3

Container appurtenances

9.3.1

Nonrecessed container fittings and appurtenances shall be protected against physical damage by either:

•

a protected location;

•

the vehicle frame or bumper; or

•

a protective housing.

The protective housing, if used, shall comply with the requirements under which the containers are fabricated for design and construction. It shall be designed to withstand static loadings in any direction equal to twice the weight of the container and attachments when filled with the lading, using a safety factor of not less than 4, based on the ultimate strength of the material to be used. The protective housing, if used, shall be protected with a weather cover, if necessary, to ensure proper operation of valves and PRDs.

9.3.2 With the exception of pressure relief valves, liquid level gauges, pressure gauges, and thermometer wells, every opening in each container shall be:

• •

provided with an excess flow valve and manual shutoff valve;

•

provided with a backflow check valve and manual shutoff valve; or

•

provided with a remotely controlled internal shutoff valve as described in 9.3.3.

closed with a plug, cap, bolted blind flange, or plate;

9.3.3

Every liquid or vapor discharge opening in each container shall be provided with a remotely controlled internal shutoff valve For every such opening of less than 1.25 in (32 mm) National Pipe Taper (NPT), an excess flow valve with a manual shutoff valve may be used instead. The internal shutoff valve may be operated by mechanical means, by hydraulic means, or by air or gas pressure.

9.3.3.1 On a container of 3500 gal (13 m3) water capacity or less, emergency discharge control equipment shall conform to 49 CFR 173.315(n) and 178.337-11(a) [7],

9.3.3.2 On a container greater than 3500 gal (13 mJ) water capacity, each internal shutott valve shall be provided with remote means of closure, both mechanical and thermal that are installed at the ends of the tank in at least two diagonally opposite locations. If the discharge connection at the tank is not in the general vicinity of one of the two locations previously specified, one additional fusible element shall be installed so that heat from a fire in that area will activate the emergency control system. Fusible elements may not have a melting point exceeding 250 °F (121 °C).

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9.3.4 The requirements of 9.3.3 do not apply to a 1.25 in (32 mm) NPT liquid or vapor discharge opening equipped with an excess flow valve and manually operated shutoff valve installed before October 1, 1984.

9.3.5 All containers shall be equipped with an approved vapor-equalizing valve of adequate capacity.

9.3.6 All containers shall be equipped with a fixed maximum liquid level gauge.

9.3.7 All containers shall be equipped with a pressure gauge having a dial graduated from 0 psi to 400 psi (0 kPa to 2760 kPa).

9.4

Piping, fittings, and hose

9.4.1 All piping, tubing, hose, and fittings shall be securely mounted and protected against physical damage.

9.4.2 Piping used on nonrefrigerated systems shall be at least ASTM A53 Grade B seamless or electric resistance welded pipe [41], Pipe joints shall be threaded, welded, or flanged. Pipe shall be at least Schedule 40 when joints are welded or welded and -flanged. Pipe shall be at least Schedule 80 when joints are threaded. Brass, copper, or galvanized steel pipe or tubing shall not be used [41]. Threaded nipples shall be seamless. Welding shall be done by a welder certified in accordance with the ASME Code, Section IX, “Welding Qualifications’’ [18]. Tubing joints shall be made up with flared, flareless or compression type fittings complying with SAE J513f, ASME B31.3, or ASME B31.5 [42, 35, 36],

9.4.3 The truck unloading line shall be provided with an excess flow valve at the hose connection unless an approved quick closing internal valve is provided in the container unloading connection. See 9.3.2.

9.4.4 Liquid propane hose shall not be used for ammonia service. See 5.7

9.4.5 All transporters of ammonia shall meet the requirements of 49 CFR Part 180.416 in relation to discharge system inspection and maintenance programs for cargo tanks transporting liquefied compressed gases [7],

9.5

Pressure relief valves

9.5.1 The discharge from container pressure relief valves shall be vented away from the container upward and unob¬ structed to the open air to prevent any impingement of escaping gas upon the container. Loose fitting rain caps shall be used to prevent moisture or foreign material from entering the relief valve outlet. The size of discharge lines from pressure relief valves shall not be smaller than the nominal size of the pressure relief valve outlet connection. Suitable provision shall be made for draining condensate that can accumulate in the discharge pipe.

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CGA G-2.1—2023

9.5.2 Pressure relief valves used on DOT containers shall be inspected, repaired, or replaced in accordance with applicable DOT regulations [7].

9.6

Placarding and marking of containers

9.6.1 Every container, whether loaded or empty, shall be conspicuously and legibly marked on each side and each end, on a background of sharply contrasting color with the proper shipping name, except that containers marked before October 1, 1991, need not be remarked ANHYDROUS AMMONIA, LIQUEFIED if the container otherwise complies with the provisions of 49 CFR 172.302 (f) [7], Markings shall have a width of at least 0.24 in (6.1 mm) and a height of at least 2.0 in (50 mm) Each container shall also be marked with the UN identification number for ammonia, 1005, on each side and each end as required by DOT regulation [/]. Under the provision of 49 CFR 172.332 (a) the UN identification number may be displayed on an orange panel or by a placard showing the UN 1005 number [7], If an orange panel is used, then an appropriate reading placard (for example, NONFLAMMABLE GAS) is also required on all four sides of the container.

9.6.2 Each container, whether empty or loaded, shall be provided with placarding on each side and on each end as required by DOT regulations [7].

9.6.3 Each container shall be marked with appropriate placarding and shall carry shipping papers for the cargo tank conforming to 49 CFR [7],

9.7

Transfer of liquids

9.7.1 The content of a cargo tank container shall be determined by weighing, suitable liquid level gauging device, or another approved method. NOTE—If the volume content of a container is to be determined by liquid level measurement, the container shall have a thermometer well and thermometer so that the internal liquid temperature can be easily determined This volume when con¬ verted to weight shall not exceed the filling density as required by DOT regulations [7]

9.7.2 Pumps or compressors shall be designed and installed in accordance with 5.10 and protected against physical damage when mounted upon ammonia tank trucks and trailers.

9.7.3 A cargo tank container of greater than 3500 gal (13 m3) water capacity shall be unloaded only at approved loca¬ tions meeting the requirements of 3.4 and 5.10.8. 9.8

Trailers and semitrailers

9.8.1 When two or more vehicles are operated in combination, the vehicles shall be designed and constructed, and the coupling devices connecting the vehicles shall be designed, constructed, and installed, so that when the combination is operated in a straight line on a smooth, level, paved surface, the path of the towed vehicle shall not vary more than 3 in (80 mm) from the path of the towing vehicle.

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9.8.2 Each trailer and semitrailer shall be equipped with an emergency braking system to be activated in the event of separation from the towing vehicle.

9.8.3 Each trailer shall be equipped with a tow bar and means of attaching the tow bar to the towed and towing vehicles. The tow bar and means of attachment shall be structurally adequate, properly and securely mounted, provide for adequate articulation, and be provided with a locking device to prevent accidental separation of the towed and towing vehicles. One or more safety devices such as a safety chain(s) or safety cable(s) shall also be properly installed to prevent the towed vehicle from breaking loose in the event of tow bar failure or disconnection.

9.8.4 Where a fifth wheel assembly is employed for towing a semitrailer, the lower half of the assembly shall be properly and securely attached to the frame of the towing vehicle. The upper half of the assembly shall be fastened to the towed vehicle in a manner providing at least the same security required for installation of the lower half. Each fifth wheel assembly shall have a positive locking mechanism that shall apply automatically on coupling, and that will prevent separation of the upper and lower halves except by activation of a manual release.

9.9

Electrical equipment and lighting

9.9.1 Tank trucks, tank trailers, and tank semitrailers may not be equipped with any artificial light other than electric light. Electric lighting circuits shall have suitable overcurrent protection (fuses or automatic circuit breakers). The wiring shall have sufficient carrying capacity and mechanical strength, and shall be suitably secured, insulated, and protected against physical damage.

9.9.2 Tank trucks, tank trailers, and tank semitrailers shall be provided with lighting devices and reflectors in accord¬ ance with the applicable provisions of 49 CFR Part 393 Subpart B [7], 9.10

Protection against collision

Each tank motor vehicle shall be provided with properly attached bumpers or chassis extensions arranged to protect the tank, piping, valves, and fittings from physical damage in case of collision.

9.11

Brakes

No ammonia shall be loaded into or unloaded from any tank truck, tank semitrailer, or tank trailer unless the handbrake and/or other brake mechanism and wheel chocks on both sides of at least one drive wheel are se¬ curely set to prevent motion of the vehicle during the loading or unloading process.

9.12

Portable tanks (including skid tanks)

When portable tanks are used in lieu of cargo tanks and are permanently mounted on highway motor vehicles for the transportation of ammonia, they shall comply with the requirements of Section 9. Where portable tanks, including those built to DOT Specification 51 or 106A, are used for farm storage they shall comply with Section 6. When portable tanks are used as shipping containers in interstate commerce they shall comply with Section 10.

9.13

Safety equipment

All tank trucks, tank trailers, and tank semitrailers (or attached power units) shall be furnished with the equipment specified in 3 5 for emergency purposes.

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Compressed Gas Association, Inc.

10 Systems using DOT portable tanks and cylinders This section applies specifically to systems using cylinders (see 2.2.15), portable tanks (DOT51, UN T50), or “ton uunlainets" (DOT-106A) constructed in accordance with DOT specifications. Section 5 applies to this section unless otherwise noted.

10.1

Containers and cylinders

10.1.1 Containers and cylinders shall comply with current DOT specifications and shall be maintained, filled, packaged, marked, labeled, and shipped to comply with current DOT regulations, OSHA regulations, and CGA C-7, Guide to Classification and Labeling of Cornpiessed Gases [7, 11, 48],

10.1.2 Containers and cylinders shall be stored in an area free from ignitable debris and to prevent external corrosion. Storage may be indoors or outdoors. Cylinders stored outdoors should be protected against accumulation of ice and snow. Cylinders in hot climates should be protected from the continuous direct rays of the sun.

10.1.3 Containers and cylinders shall not be buried underground.

10.1.4 Containers and cylinders shall be set upon firm, level surfaces or otherwise firmly secured. The possible effect of settling or frost heave on the outlet piping shall be guarded against by appropriate use of a flexible connection ~or special fitting. ‘

—

10.1.5 Containers and cylinders shall be protected from heat sources such as radiant flame and steam pipes. Heat shall only be applied directly to containers or cylinders to raise the pressure in accordance with 5.14. A cylinder filled in accordance with DOT regulations will become liquid full at 145 °F (62.8 °C) and will rupture upon further temperature rise. NOTE—Elevated temperatures can cause a relief valve release or a rupture due to high liquid level and or vapor pressure.

10.1.6 Containers and cylinders shall be stored to protect them from moving vehicles or external damage.

10.1.7 Any container or cylinder that is designed to have a valve protection cap or device shall have the cap or device securely in place when the container or cylinder is not in service. This requirement need not apply at a facility specifically designated for filling containers or cylinders.

10.1.8 Any process system connected to a container or cylinder shall be equipped with a suitable trap or backpressure check valve to prevent the entry of foreign matter into the container or cylinder.

10.2

Container and cylinder valves and regulating equipment

10.2.1 Container and cylinder valves and pressure regulating equipment shall be protected against tampering when installed for use.

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10.2.2 Container and cylinder valves shall be protected while in transit, in storage, and while being moved before con¬ nection to the process line, as follows:

•

By setting them into a recess of the container;

•

By ventilated metal cap or collar, fastened to the container, capable of withstanding a blow from any direction equivalent to that of a 30 lb (14 kg) weight dropped 4 ft (1.2 m). Construction shall be such that a blow will not be transmitted to the valves or other connections; or

•

A valve on a cylinder that is enclosed in a suitable box or crate of sufficient strength to protect the valve from damage during transit or storage need not be provided with a protective cap or collar.

10 2.3 When containers or cylinders are not connected for service, the outlet valves shall be kept tightly closed and protected even though containers are considered empty. This requirement need not apply at a facility specifically designated for filling containers or cylinders.

10.2.4 Cylinder valves shall be in accordance with the connection standard for ammonia as contained in CGA V-1, Standard for Compressed Gas Cylinder Valve Outlet and Inlet Connections [49].

10.3

Pressure relief devices

Containers shall be provided with PRDs as required by DOT regulations [7] A cylinder containing less than 165 lb (75 kg) of ammonia is not required to have a PRD.

PRD equipment used on DOT containers shall be inspected, repaired, or replaced in accordance with applicable DOT regulations [7].

11 Applicator tank and nurse tank systems mounted on farm wagons (implements of husbandry) This section applies to containers of 3000 gal (11 m3) water capacity or less and related equipment mounted on farm wagons (implements of husbandry) that are used for the application and transportation of ammonia. Section 5 applies to this section unless otherwise noted. If the data plate is illegible or missing, systems covered by this section (nurse tanks) shall comply with DOT regulations [7],

11.1

Design pressure and construction of containers

The minimum design pressure for containers shall be 250 psi (1724 kPaf See 5.1.1 and 5.2.

11.2

Mounting of containers

11.2.1 A suitable “stop” or "stops” shall be mounted on the farm wagon or on the container in such a way that the container shall not be dislodged from its mounting due to the farm wagon coming to a sudden stop. Back slippage shall also be prevented by proper methods.

11.2.2 A suitable “hold-down" device shall be provided that anchors the container to the farm wagon at two or more places on each side of the container.

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CGA G-2.1—2023

11.2.3 When containers are mounted on farm wagons, care shall be taken to ensure that the weight is distributed appropriately over the axles.

11.2.4 When the cradle and the container are not welded together, suitable material shall be used between them to reduce abrasion. Sec 5.2.2.1 and 5.2.4 with regard to welding on a container.

11.2.5 Applicator tanks

11.3

shall be securely mounted.

Container appurtenances

11.3.1 All containers shall be equipped with a fixed maximum liquid level gauge that is designed, installed, and maintained to indicate when the container has been filled to 85% of its water capacity

11.3.2 All containers shall be equipped with a pressure gauge having a dial graduated from 0 psi to 400 psi (0 kPa to 2760 kPa).

11.3.3 Withdrawal valves mounted on the front end of a nurse tank shall be globe or “Y" pattern valves unless they are nurse tank wagon, in which case, they may be angle valves.

protected by a separate mechanically secure point on the

11.3.4 The filling connections of each container shall comply with the requirements of 5.5.11. Flow capacity of the ex¬ cess flow valve shall not exceed 45 gallons per minute (gpm) for 1 1/4 in tank connections and 60 gpm for 1 1/2 in tank connections

11.3.5 All containers shall be equipped with an approved vapor-equalizing valve unless equipped for spray loading

11.3.6 When using an open yoke type excess flow valve in a tank opening, the opening shall not be reduced with bushings to accommodate the valve.

11.3.7 All vapor and liquid connections, except pressure relief valves and those specifically exempt in 5.5.5 and 5.5.6, shall be equipped with approved excess flow valves or may be fitted with quick-closing internal valves that shall remain closed except during filling and field applications Flow capacity of the excess flow valve shall not exceed 45 oom for 1 1/4 in tank connections and 60 gpm for 1 1/2 hi tank connections.

Excess flow valves shall be configured to close automatically at the rated flows of vapor or liquid as specified by the manufacturer. The plumbing system including valves, fittings, and hose being protected by an excess flow valve shall use nominal pipe size equal to or greater than the excess flow valve, so the excess flow valve has the greatest opportunity to close or shall be designed by a competent individual knowledgeable in the flow of fluids. The piping, including valves, fittings, and hose being protected by an excess flow valve, shall have a

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greater capacity than the rated flow of the excess flow valve, so the valve will likely close in case of failure at any point in the line or fittings.

11.3.8 An excess flow valve is not reguired in the vapor connection, provided the controlling orifice is not in excess of 0.4375 in (11.1 mm) in diameter and the valve is a hand-operated (attached handwheel or eguivalent) shutoff valve. To assist in filling applicator tanks, it is permissible to bleed vapors to the open air, provided the preceding reguirements are met.

11.3.9 No excess flow valve is reguired in the liquid withdrawal line provided the controlling orifice between the contents of the container and the outlet of the shutoff valve (see 5.5 3) does not exceed 0.4375 in (11 1 mm) in diameter

11.3.10

Multiple container plumbing

All plumbing configurations used to transfer ammonia from single or multiple tanks to the applicator shall be designed to likely stop the ammonia flow in the event of hose or piping failure. This configuration shall be installed immediately after the merged connection and can be accomplished by methods that include, but are not limited to, guick-closinq internal tank valves, backcheck valves, or properly rated excess flow valve(s) as specified in 11.3.7. Refer to the AHJ for proper installation to accomplish safe operation of each specific unit.

11.3.11 Nurse tank appurtenances shall be protected from physical damage by means of a rigid guard designed to with¬ stand staticJoading in any direction equal to twice the weight of the container and lading using a safetydactor of 4 based upon the ultimate strength of the material used. If the guard encloses the pressure relief valve,The valve shall be properly vented through the guard.

11.3.12 If a liquid withdrawal line is installed in the bottom of a container, the connections thereto, including hose, shall not be lower than the lowest horizontal edge of the farm wagon axle. The hose shall be drained and depressurized before the container is moved or towed on a public road.

11.3.13 Provision shall be made to secure both ends of the hose in transit.

11.3.14 Containers and systems covered under Section 11 shall comply with all requirements in 49 OFR 173.315(m) [7]

11.4

Marking and placarding of containers

11.4.1 Each container transporting ammonia shall be marked with the proper shipping name, and the words INHALATION HAZARD on two opposing sides (see Special Note 13 in 49 CFR 172.102), except that containers marked before October 1, 1991, need not be remarked ANHYDROUS AMMONIA, LIQUEFIED if the container otherwise complies with the provisions of 49 CFR 172.302 (f) [7]. If the container has a capacity of 1000 gal (3785 L) or more, ANHYDROUS AMMONIA markings and UN 1005 placards shall appear on each end and each side. If the container has a capacity less than 1000 gal (3785 L), ANHYDROUS AMMONIA markings and UN 1005 placards shall appear on two opposing sides. Markings shall have a width of at least 0.24 in (6.1 mm) and a height of at least 2.0 in (50 mm). The container need not be marked or placarded on one end if that end contains valves, fittings, regulators, or gauges when those appurtenances prevent the markings and placard from being properly placed and visible. See 49 CFR 172.302 and 173 315 (m) [7],

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Compressed Gas Association. Inc.

CGA G-2.1—2023

11.4.2 Slow-moving farm wagons operating on public roads shall be provided with a slow-moving vehicle emblem con¬ sisting of a fluorescent orange triangle with a red reflective border whenever that vehicle is towed at or less than the slow-moving vehicle speed limit as established by state or local regulations. A driver of a slow-moving motor vehicle may activate the vehicular hazard warning signal flashers to warn other drivers of the presence of a potential traffic hazard if permitted to do so by state or local regulations. For information regarding construction, location, and mounting of the emblem, see ANSI/ASAE/ASABE S276.8, Slow-Moving Vehicle Identification Em¬ blem (SMV Emblem) [50], See also 29 CFR 1910.145(d) (10) [10],

11.5

Farm wagons (implements of husbandry)

11.5.1 Farm wagons (implements of husbandly) shall conform with jurisdictional regulations. 11.5.2 All farm wagons shall be securely attached to the vehicle or an implement of husbandry drawing them by means of drawbars supplemented by suitable hitch pins with retainer clips and safety chains.

Two safety chains shall be separately secured off center of the wagon tongue and of sufficient length to allow for crossing under the wagpn tonque when connected to the towing implement or vehicle. Each safety chain and its securement and connection points shall be of minimum breaking force (MBF) to independently support in the line of travel the gross weight of the lank and wagon assembly. For farm

wagons designed to tow an additional farm wagon, the MBF of each safety wagons designed to tow an additional farm wagon shall be equal to or greater than the

of the farm wagons in tow. ;;

“

chain installed on farm combined gross weight

'

A farm wagon shall be constructed and maintained so that it will follow substantially in the path of the towing vehicle and will prevent the towed farm wagon from whipping or swerving dangerously from side to side.

11.5.3 A farm wagon shall not be towed in public places such as school yards, malls, or hospital grounds without ap¬ proval of local authorities.

11.6

Transfer hose

11.6.1 During transport upon a public riqht-of way, all transfer hose valves, applicator tank valves, and nurse tank valves shall be closed. Provision shall be made to protect the withdrawal or transfer hose from damage during transport upon a public right-of-way.

11.6.2

Valves and acme fittings used to connect the supply line to an applicator tank or nurse tank shall be inspected wear on acme threads A locking feature may be used to prevent acme fittings from loosening during field application. annually for

11.7

Safety training and equipment

Each person operating, repairing appurtenances, or inspecting a nurse tank shall comply with the requirements in 3.1 and 3.2.

CGA G-2.1—2023

11.8

Compressed Gas Association, Inc.

Page

59

Safety water, decal, and safety data sheet

Each applicator tank or nurse tank shall be equipped with the following safety equipment and features:

•

For first aid purposes, at least 5 gal (20 L) of clean water in a container designed to provide ready access to the water for flushing any area of the body contacted by ammonia; and

•

A legible decal listing first aid procedures to follow if injured by ammonia.

A safety data sheet (SDS) complying with 29 CFR 1910 1200 shall be made available upon request [11]

11.9

Compatibility

Before the addition of a chemical additive, its compatibility with ammonia systems including liquid and vapor components (for example, appurtenances, containers, etc.) shall be verified.

12 Ammonia application systems (implements of husbandry) This section applies to ammonia application systems used for the field application of ammonia. Section 5 applies to this section unless otherwise noted.

12.1

Ammonia application unit

See 2.2.4.

12.2

Metering devices

Metering devices may be connected directly to the tank withdrawal valve. A union-type connection is permissible between the tank valve and the metering device. Remote mounting of metering devices is permissible using hose that meets with specifications in 5.7.

12.3

Breakaway coupling devices and instructions

12.3.1 When the nurse tank is trailing an ammonia application unit, other implement, or nurse tank, each withdrawal hose on each hitch connection shall be protected with its own automatic breakaway coupling device This cou¬ pling device shall be:

•

made from, or coated with, a corrosion-resistant material; and

•

inspected, installed, maintained, and operated in accordance with the

manufacturer's instructions.

The hose supplying the applicator shall not drop low enough to touch the nurse tank tongue and shall be unob¬ structed so as to allow the safe operation and articulation of the automatic breakaway coupling device. An angle valve shall not be used as a hose end valve connecting to the breakaway coupling device.

12.3.2 Instructions for connecting and disconnecting the breakaway coupling device shall be displayed to be readily visible and legible near the breakaway coupling device.

12.4

Control valves

Any control valve on the ammonia application unit shall indicate whether the valve is open or closed.

12.5

Ball valves

Where a ball valve is used on an ammonia application unit, the ball shall have a means to prevent trapping ammonia in the ball when in the closed position.

Page 60

12.6

Compressed Gas Association, Inc.

CGA G-2.1—2023

Bleed valves

A bleed valve should be installed to allow for safe removal of ammonia.

12.7

Withdrawal hose

12.7.1 From the liquid withdrawal valve up to the rate control device on the ammonia application unit, means shall be made to protect the liquid withdiawul hose assemblies from damage.

12.7.2 During transport on a public right-of-way, all transfer hose valves, applicator tank valves, and nurse tank valves shall be closed. Provision shall be made to protect the liquid withdrawal hose fiom damage during tianspoit on a public right-of-way.

12.8

Transfer system

A pump capable of producing flow at a pressure greater than the maximum system working pressure shall be equipped with a pressure regulation device on the discharge side of the pump. A 0 psi to 400 psi (0 kPa to 2760 kPa) rated pressure gauge shall be installed in or in close proximity of the pump discharge.

12.9

Safety training and equipment

Each person operating, repairing appurtenances, or inspecting an ammonia application unit shall comply with the requirements of 3.1 and 3.2. For emergencies, any person applying ammonia should carry and should have readily accessible respiratory personal protective eguipment (PPE) suitable for escape.

12.10

Compatibility

Before the addition of a chemical additive, its compatibility with ammonia systems including liquid and vapor components (for example, appurtenances, containers, etc.) shall be verified.

13 References Unless otherwise specified, the latest edition shall apply. [1] ANSI/IIAR 2, American National Standard for Design of Safe Closed-Circuit Ammonia Refrigeration Sys¬ tems, International Institute of Ammonia Refrigeration, www iiar.org [2] ANSI/IEEE SI 10, American National Standard for Metric Practice, Institute of Electrical and Electronics En¬ gineers. www.ieee orq [3] Rlanken, .I M ,1980, Behavior of Ammonia in the Event of Spillage, 0149-3701-80-3963, American Institute of Chemical Engineers, www.aiche.org

[4] Handbook of Compressed Gases, Compressed Gas Association, Inc. www cganet com [5] CGA P-11, Guideline for Metric Practice Guide in the Compressed Gas Industry, Compressed Gas Associa¬ tion, Inc. www.cganet.com [6] NFPA 45, Standard on Fire Protection for Laboratories Using Chemicals, National Fire Protection Associa¬ tion. www.nfpa.org

[7] Code of Federal Regulations, Title 49 (Transportation), U.S. Government Printing Office, www gpo.gov

CGA G-2.1—2023

COMPRESSED GAS ASSOCIATION, INC.

PAGE 61

[8] Documentation for Immediately Dangerous to Life or Health Concentrations, ''Ammonia”, National Institute for Occupational Safety and Health, Center for Disease Control and Prevention, www.cdc.qov/niosh

[9] Acute Exposure Guideline Levels for Selected Airborne Chemicals, 2007, The National Academies Press. www.nap.edu

[10] NIOSH Pocket Guide to Chemical Hazards, National Institute for Occupational Safety and Health, Center for Disease Control and Prevention, www cdc.gov/niosh [11] Code of Federal Regulations, Title 29 (Labor) Parts 1900-1910, U.S. Government Printing Office www.qpo.gov

[12] Emergency Response Planning Guidelines for Ammonia, 2000, American Industrial Hygiene Association. www.aiha.org

[13] Transportation of Dangerous Goods Regulations, Transport Canada, Canadian Government Publishing Centre, www.tc.gc.ca

[14] Regulations for the Transportation of Dangerous Commodities by Rail, Supply and Services Canada, Ca¬ nadian Publications Centre, www.tc.qc.ca [15] Code of Federal Regulations, Title 30 (Mineral Resources), Parts 1-199, U.S. Government Printing Office, www.qpo.gov

[16] ANSI Z88.2, Respiratory Protection— Respirator Use—Physical Qualifications for Personnel, American Na¬ tional Standards Institute, www.ansi.org [17] API-ASME Code for Unfired Pressure Vessels for Petroleum Liquids and Gases (discontinued 1956)

[18] ASME Boiler & Pressure Vessel Code ^American Society of Mechanical Engineers, www.asme.org [19] National Board Inspection Code, National Board of Boiler and Pressure Vessel Inspectors, www national¬ board.org [20] ANSI/ASSE Z87.1, American National Standard for Occupational and Educational Personal Eye and Face Protection Devices, American National Standards Institute, www.ansi.org [21] ANSI/ISEA Z358.1, American National Standard for Emergency Eyewash and Shower Equipment, Ameri¬ can National Standards Institute, www. ansi org [22] CGA G-2, Anhydrous Ammonia, Compressed Gas Association, Inc. www.cqanet.com [23] Code of Federal Regulations, Title 40 (Protection of Environment) Parts 1-799, U.S. Government Printing Office, www.qpo.gov

[24] Code of Federal Regulations, Title 6 (Domestic Security), U.S. Government Printing Office, www.gpo.gov

[25] CGA P-50, Standard for Site Security, Compressed Gas Association, Inc. www.cganet.com [26] CGA P-26, Guidelines for Inspection and Repair of MC-330 and MC-331 Anhydrous Ammonia Cargo Tanks (formerly TB-2), Compressed Gas Association, Inc. www.cqanet.com [27] API 510, Pressure Vessel Inspection Code: In-Service Inspection, Rating, Repair, and Alteration, American Petroleum Institute, www api.org [28] API RP 580, Risk-based Inspection, American Petroleum Institute, www.api.org [29] API RP 581, Risk-based Inspection Methodology, American Petroleum Institute, www.api.org

[30] K61.1 , Safety Requirements for the Storage and Handling of Anhydrous Ammonia, Compressed Gas As¬ sociation, Inc . www.cqanet.com (no longer published)

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Compressed Gas Association, Inc.

CGA G-2.1—2023

[31] CGA G-2.1 , Standards for the Storage and Handling of Anhydrous Ammonia and Ammonia Solutions, Compressed Gas Association, Inc. www cqanet.com (obsolete) [32] Standard M-1, Standard for Storage and Handling of Agricultural Ammonia, The Agricultural Nitrogen Insti¬ tute (now The Fertilizer Institute), www.tfi.orq (no longer published)

[33] Transportation Glossary, American Association of State Highway and Transportation Officials, www.transportation.orq

[34] ASHRAE 15, Safety Standard for Refrigeration Systems, American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). www.ashrae.org [35] ASME B31.3, Process Piping, American Society of Mechanical Engineers www asme.org

[36] ASME B31.5, Refrigeration Piping and Heat Transfer Components, American Society of Mechanical Engi¬ neers. www asme orq [37] ASTM A105, Standard Specification for Carbon Steel Forging for Piping Applications, ASTM International. www.astm.org

[38] ASTM A234, Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moder¬ ate and High Temperature Service, ASTM International, www.astm orq

[39] ASTM A395, Standard Specification for Ferritic Ductile Iron Pressure-Retaining Castings for Use at Ele¬ vated Temperatures, ASTM International, www.astm.org [40] ASTM A47, Standard Specification for Ferhtic Malleable Iron Castings, ASTM International, www.astm orq [41] ASTM A53, Standard Specification for Pipe, Steel, Seamless, ASTM International, www.astm.org

Blac^and Hot-Dipped, Zinc-Coated, Welded and

[42] SAE J513f, Refrigeration Tube Fittings-General Specifications, SAE International, www sae.org [43] CGA P-82, Standard for Maintenance of Transfer Hoses, Compressed Gas Association, Inc.

www cganet.com [44] UL-132, Standard for Safety Relief Valves for Anhydrous Ammonia and LP-Gas, Underwriters Laborato¬ ries, Inc. www.ul.com [45] API 620, Design and Construction of Large, Welded, Low-Pressure Storage Tanks, American Petroleum Institute, www.api.org

[46] NFPA 70, National Electrical Code®, National Fire Protection Association, www nfpa.org [47] API 2000, Venting Atmospheric And Low-Pressure Storage Tanks, American Petroleum Institute

www api.org [48] CGA C-7, Guide to Classification and Labeling of Compressed Gases, Compressed Gas Association, Inc. www.cganct.com

[49] CGA V-1, Standard for Compressed Gas Cylinder Valve Outlet and Inlet Connections, Compressed Gas Association, Inc. www.cganet.com [50] ANSI/ASAE/ASABE S276.8, Slow-Moving Vehicle Identification Emblem (SMV Emblem), American Soci¬ ety of Agricultural and Biological Engineers, 2950 Niles Road, St. Joseph, Ml 49085 www.asabe orq

CGA G-2.1—2023

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COMPRESSED GAS ASSOCIATION, INC.

Appendix A—Minimum required flow rate of pressure relief devices for fire protection (Normative) Pressure relief valves for excessive heat or fire protection used on containers covered by Sections 6, 11 , and 12 shall be constructed to discharge at not less than the rates required in Appendix A before the pressure is in excess of 121% of the MAWP of the container. Relief protection for any other reason shall use ASME UG-125 UG-126, UG-127, UG-128, UG-129, UG-130, UG-131, UG-132, UG-133, UG-134, UG-135, and UG-136 [18]. Surface area,

Flow rate

Surface

Flow rate

Surface area,

Flow rate

Surface area,

Flow rate

Surface area,

Flow rate

Surface area,

Flow rate

Surface area,

Flow rate

Surface

area,

area,

Flow rate

ft2

ft3/min

m2

m3/min

ft2

m2

m3/min

ft2

fP/min

m2

m3/min

ft2

fP/min

m2

m3/min

37 1

340

air 2640

125.4

231 0

73

145

ff/min air 1 310

23

88

150

1 350

13 9

38.1

350

28

10.2

155

1 390

14 4

39.2

360

air

air

20

258

19

25

310

30

360

air

13 5

air

air

air

31 6

74 6

1350

8160

2700

32.5

76 3

1400

8410

130 1

237 9

2760

33.5

78 1

1450

8650

134 7

244 9

370

2830

34.4

8900

139 4

251 8

2890

35.3

79.9 81.7

1500

380

1550

9140

144 0

258 7

390

2950

36.2

83.4

1600

9380

148 6

265.5

3010

37.2

85.2

1650

9620

153 3

272.3

35

408

33

11.6

160

1 420

14 9

40

455

37

12.9

165

1 460

15.3

45

501

4.2

14.2

170

1 500

15 8

40.2 41.2 42 2

50

547

4.7

155

175

1 530

16 3

43.2

400

55

591

5.1

16 7

180

1 570

16 7

44.3

450

3320

41.8

93.8

1700

9860

157 9

279 0

60

635

18.0

185

1 600

17.2

45.3

500

3620

46.5

102.3

1750

10 090

162 6

285.7

65

678

1 640

17.7

46.3

550

3910

51.1

110.6

1800

10 330

167.2

292.4

720

19.2 20.4

190

70

5.6 6.0 65

195

1 670

18.1

47.3

600

4200

55.7

118.8

1850

10 560

171 9

299 0

75

762

7.0

21.6

200

1 710

18 6

48.3

650

4480

60 4

126 8

1900

10 800

176 5

305.6

80

804

74

22 8

210

1 780

19 5

50.2

65 0

134.8

1950

11 030

181.2

312.2

845

79

23 9

220

1 850

20.4

52.2

700 750

4760

85

5040

69.7

142.6

2000

11 260

185 8

318 8

90

885

84

25 1

230

1 920

21.4

54 1

800

5300

74 3

150 4

2050

11 490

190.5

325.3

95

925

88

26 2

240

1 980

22.3

56 0

850

5590

79 0

2100

11 720

195 1

331 8

2150

11 950

199 7

338 3

2200

12 180

204 4

344 7 351 1

100

965

93

2 050

23 2

57 9

900

5850

83 6

1010

98

27 3 28 5

250

105

260

2 120

24.2

59.8

950

6120

88 3

158 0 165 6 173 1

110

1050

102

296

270

2 180

25 1

61 7

1000

6380

92 9

180 6

2250

12 400

209 0

115

1090

10 7

30 7

280

2 250

26 0

63 6

1050

6640

97 6

187 9

2300

12 630

213 7

357 5

120

1120

11 2

31 7

290

2 320

26 9

65 4

1100

6900

102.2

195 2

2350

12 850

218 3

363 8

370.2

125

1160

11 6

32 8

300

2 380

27 9

67 3

1150

7160

106 8

202.5

2400

13 080

223 0

130

1200

12 1

33 9

310

2 450

28 8

69 1

1200

7410

111 5

209.7

2450

13 300

227 6

376.5

135

1240

12 5

35 0

320

2 510

29 7

70 9

1250

7660

116 1

216 8

2500

13 520

232.3

382 8

140

1280

13 0

36 0

330

2 570

30 7

72 8

1300

7910

120.8

223 9

2550

13 739

236 9

389 0

NOTES

Surface area = total outside surface area of container in square feet When the surface area is not stamped on the name plate or when the marking is not legible, the area can be calculated by using one of the following formulas: (1) Cylindrical container with hemispherical heads—Area = overall length (ft) x OD (ft) x 3.1416 (2) Cylindrical container with other than hemispherical heads—Area = (overall length [ft] + 0.3 OD [ft]) x OD (ft) x 3.1416 (3) Spherical container—Area = OD (ft2) x 3 1416

Flow rate ft3/min air = ft3/min of air required at standard conditions, 60 °F (15 6 °C) and atmospheric pressure (14.7 psia, [101 3 kPa, abs]) The rate of discharge may be interpolated for intermediate values of surface area For containers with total outside surface area greater than 2500 ft2, the required flow rate can be calculated using the formula: Flow rate

ft3/min air = 22 11 A0 82

Where A = outside surface area of the container in square feet

Conversion factors:

• ft2 x 0 092903 = m2 • ft3/min x 0 028 317 = m3/min ft x 0 3048 = m