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CODES & STANDARDS, PART FOUR OF MANY: REFRIGERATION STANDARDS & CODES

I n February 1968, a Tentative Interim Amendment (TIA) #146 was released, amending the National Electric Code (NEC) by adding ammonia to the list of Group D Hazardous Atmospheres. This TIA became an immediate provision of the 1968 NEC and was automatically included in the 1971 NEC provisions. This TIA forced all ammonia refrigeration machinery rooms to be treated as hazardous, or classified locations, requiring explosion proof equipment and intrinsically safe wiring methods. This would burden ammonia refrigeration systems with a significant cost penalty and place them at a severe disadvantage over other, refrigerants, particularly synthetic. During the 1971 development cycle for the NEC, two proposals were submitted in attempts to “undo the damage,” so to speak. The Compressed Gas Association (CGA) submitted Proposal #6 to delete ammonia from Group D outright. This proposal was rejected by the NEC Tech- nical Committee. The Air-Conditioning

and Refrigeration Institute (ARI)—now known as The Air-Conditioning, Heating and Refrigeration Institute (AHRI)—sub mitted Proposal #9, which attempted to exclude closed-circuit ammonia refrigera tion systems from the Group D classifica tion. The committee did not accept this change outright but held it for further consideration. Ultimately, the NEC Technical Committee approved a modification to the 1971 NEC that helped the ammonia refrigeration industry by adding a reference for ammonia refrigeration to be classified in accordance with ANSI B9.1, which was the predeces sor of American Society of Heating, Re- frigerating and Air-Conditioning Engi neers (ASHRAE) Standard 15. While this amendment helped to solidify ammonia refrigeration as the predominant form of industrial refrigeration, leaders in the industry realized that a dedicated lobbying group was needed to support the industry’s interests, rather than rely on broader, com- pressed gas or refrigeration associations.

In the last issue, I presented a synopsis of the American Society of Mechanical Engineers’ (ASME) B31.5, which is the “Refrigeration Piping and Heat Transfer Components” code. In this issue, I will discuss the creation of the International Institute of Ammonia Refrigeration (IIAR) and the history behind its suite of

standards for ammonia refrigeration systems.

By Bill Lape, CIRO, CRST

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