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OSHA Standards

State Standards

There are twenty-eight OSHA-approved State Plans, operating state-wide occupational safety and health programs. State Plans are required to have standards and enforcement programs that are at least as effective as OSHA's and may have different or more stringent requirements.

This section highlights OSHA standards, preambles to final rules (background to final rules), directives (instruction to OSHA staff), official letters of interpretation (official letters of interpretation of the standards), and national consensus standards related to ammonia refrigeration.

This section also contains a partial list of good engineering practices which may also apply to many ammonia refrigeration facilities. This list is not intended to be all-inclusive or definitive, but should provide employers with a starting point for finding applicable codes, standards, and guidelines.


General Industry (29 CFR 1910)

  • 1910.38, Emergency action plans [related topic page]
  • 1910.119, Process safety management of highly hazardous chemicals. Applies to systems containing 10,000 lbs. of ammonia or greater. [related topic page]
    • Appendix A, List of highly hazardous chemicals, toxics and reactives (Mandatory)
    • Appendix B, Block flow diagram and simplified process flow diagram (Nonmandatory)
    • Appendix C, Compliance guidelines and recommendations for process safety management (Nonmandatory)
    • Appendix D, Sources of further information (Nonmandatory)
  • 1910.120, Hazardous waste operations and emergency response. Generally, the emergency response requirements of 29 CFR 1910.120(q) apply to employers who use refrigeration systems utilizing anhydrous ammonia as a cooling agent. [related topic page]
    • Appendix A, Personal protective equipment test methods
    • Appendix B, General description and discussion of the levels of protection and protective gear
    • Appendix C, Compliance guidelines
    • Appendix D, References
    • Appendix E, Training curriculum guidelines (Non-mandatory)
  • 1910.132, General requirements (Personal protective equipment) [related topic page]
  • 1910.133, Eye and face protection [related topic page]
  • 1910.134, Respiratory protection [related topic page]
  • 1910.138, Hand protection
  • 1910.307, Hazardous (classified) locations. There may be locations in an ammonia refrigeration system that are Class 1 Division 2 hazardous locations.
  • 1910.1200, Hazard communication. Employers are required to communicate the hazards associated with working with ammonia to appropriate employees. [related topic page]

Preambles to Final Rules


Letters of Interpretation

National Consensus

Note: These are NOT OSHA regulations. However, they do provide guidance from their originating organizations related to worker protection.

American National Standards Institute (ANSI)/International Institute of Ammonia Refrigeration (IIAR)

  • 2-1999, American National Standard for Equipment, Design, and Installation of Ammonia Mechanical Refrigerating Systems. Guides the design, manufacture, installation, and use of ammonia mechanical refrigerating systems in industrial occupancies.

American National Standards Institute (ANSI)/American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE)

  • 15-2007, Safety Code for Mechanical Refrigeration. Promotes the safe design, construction, installation, and operation of refrigerating systems. Establishes reasonable safeguards of life, limb, health, and property; defines practices that are consistent with safety; and prescribes safety standards. The provisions of this code are not intended to apply to the use of water as a refrigerant.
  • 26-1996, Mechanical Refrigeration and Air-Conditioning Installations Aboard Ship. Provides recommendations and requirements for the safe and efficient design, construction, installation, operation, inspection, and maintenance of mechanical refrigeration equipment aboard ships.

American Society of Heating Refrigerating and Air-conditioning Engineers (ASHRAE)

  • 2006 Handbook - Refrigeration. Covers the refrigeration equipment and systems used for applications other than human comfort. Includes information on cooling, freezing, and storing food; industrial applications of refrigeration; and low-temperature refrigeration. Primarily a reference for the practicing engineer, but also a useful reference for anyone involved in the cooling and storage of food products.
    • Chapter 3, System Practices for Ammonia Refrigerant
    • Chapter 6, Control of Moisture and Other Contaminants in Refrigerant Systems

American Society of Mechanical Engineers (ASME)

  • B31.5-2001, Refrigeration Piping and Heat Transfer Components
  • Boiler and Pressure Vessel Code, 2007 Edition
    • Section V, Nondestructive Examination
    • Section VIII, Pressure Vessels

Compressed Gas Association (CGA)

  • G-2.1, American National Standard Safety Requirements for the Storage and Handling of Anhydrous Ammonia, (1999). Includes standards for the location, design, construction, and operation of anhydrous ammonia systems. Sections on refrigerated storage systems, systems mounted on farm vehicles, tank motor vehicles, and tank railcars for transportation purposes are included. This standard does not apply to ammonia manufacturing plants, or refrigerating or air conditioning systems.

FM Global

  • 7-13, Mechanical Refrigeration, (2007). Property Loss Prevention Data Sheet.

International Institute of Ammonia Refrigeration (IIAR)

  • Ammonia Data Book. Provides a variety of information on ammonia and includes a data on the various properties of ammonia and information on its use.

IIAR Bulletins/Guidelines

  • Suggested Safety and Operating Procedures When Making Refrigeration Plant Tie-Ins. No. 107-1997. Addresses the need to approach ammonia refrigeration system tie-ins in a safe and methodical manner. Provides owners and contractors with a general checklist of safety and logistical items that should be reviewed when planning system shutdowns and tie-ins. Provides engineers with ideas on how and where to design for future connections and taps that can make future tie-ins easier and safer.
  • Water Contamination in Ammonia Refrigeration Systems. No. 108-1986. Addresses the water contamination in ammonia refrigeration systems that has always been a problem, as owners typically know they have water in a system, but may not be familiar with how it got there; measures to quantify the amounts, analyzing the specific penalties it causes on the system performance; and removing the water in a safe manner. Offers insights on where the water can come from and how to minimize continued infiltration. Provides an analytical approach to quantifying water concentrations, and recommends apparatus to remove the water.
  • Minimum Safety Criteria for a Safe Ammonia Refrigeration System. No. 109-1997. Embraces an IIAR goal of ensuring that ammonia refrigeration systems are engineered, constructed and operated in a safe manner. Provides detailed lists of items to consider when designing, inspecting, or operating a system. Addresses such issues as housekeeping, record keeping, code considerations and personnel safety equipment. Provides inspection checklist forms for compressors, condensers, evaporators, vessels and heat exchangers to check system installation against recognized industry safety requirements.
  • Start-Up, Inspection and Maintenance of Ammonia Mechanical Refrigerating Systems. No. 110-1993. Covers ammonia characteristics and hazards, inspection and maintenance of equipment, start-up issues, reference standards, safety equipment, and log book record keeping. Provides definitions of system components and terms to help in understanding ammonia systems.
  • Ammonia Machinery Room Ventilation. No.111-2002. Provides a practical ventilation design criteria that will satisfy existing code requirements and improve machinery room safety. Major differences can be found between codes when determining ventilation requirements for ammonia machinery rooms. These differences result in confusion for the engineer and possible code misapplication.
  • Ammonia Machinery Room Design. No. 112-1998. Summarizes generally accepted industry practice for ammonia machinery rooms, and references relevant codes and standards where instructive. The recommendations in this guideline are most applicable to completely new ammonia machinery rooms. Application to the evaluation and/or renovation of existing machinery rooms may be impractical for a variety of reasons and should be done only with careful consideration.
  • Identification of Ammonia Refrigeration Piping and System Components. No. 114-1991. Provides a comprehensive ammonia labeling scheme for companies in need of an identification system that "covers it all." Offers recommendations on label sizes, colors, installation locations, and label material requirements.
  • Avoiding Component Failure in Industrial Refrigeration Systems Caused by Abnormal Pressure or Shock. No. 116-1992. Identifies three significant factors that can lead to ammonia refrigeration system damage and personnel injury: trapped liquid, sudden liquid deceleration, and vapor propelled liquid. Explains the most likely causes for each of these problems and provides design, operation and servicing tips that can minimize the chances of them occurring. Offers numerous suggestions on making hot gas defrost operations safer and more effective.
  • Process Safety Management Guidelines, (1998). Provides guidance on the interpretation and implementation of the OSHA Process Safety Management Standard. Contains a chapter discussing each of the fourteen elements and includes a series of work practices, checklists, and other guidance materials to assist employers in developing a process safety management program.
  • Risk Management Program Guidelines for Ammonia Refrigeration, (1998). Provides guidance on the interpretation and implementation of EPA's Risk Management Rule. A good companion to the Process Safety Management Guidelines manual also published by IIAR.
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