The Natural Refrigeration

To understand how far the industrial refrigeration industry has come in the last decade, and where it’s headed, the best place to look is its standards. The International Institute of All-Natural Refrigeration has nine standards, a suite of consensus-based, ANSI-approved guides covering everything from putting a system together to taking it out of service.

Jake Denison, Senior Product Manager at Evapco, and subcommittee Chair for IIAR-1, said the standard, Definitions and Terminology Used in IIAR Standards, can be a valuable starting point for anyone looking to learn about the industry or provide context for IIAR’s suite of standards.

“Some people might gloss over the existence of IIAR-1, but it exists to help provide context and consistency across all our standards with a unified set of definitions,” said Denison. He added that IIAR-1 is unique from the rest of the IIAR standards in two key ways.

First, the standard is free to the public, a feature that helps IIAR educate newcomers or people outside the industry on important terms and definitions. Second, the standard is not adopted by model codes because model codes do not recognize definitions as standards.

The first published copy of IIAR-1 contained 106 definitions in 2012, with the largest update in 2022 adding 50 new and 10 revised definitions. The next version of the standard will be published in mid-2027.

“IIAR-1 serves as a common thread; it’s the backbone across all our standards,” said Denison. “People have different backgrounds, so it’s important to maintain consistency across all of our standards as they evolve and grow.”

Meanwhile, one of the most well-known standards, IIAR-2: Standard for Design of Safe Closed-Circuit Ammonia Refrigeration Systems, provides the minimum design requirements for all new and modified ammonia systems.

IIAR-2’s subcommittee Chair Mark Bazis, VP, Refrigeration Consultants Inc., said IIAR-2 is important because it establishes a uniform, nationally recognized design basis for ammonia systems that have been adopted into all U.S. model codes.

The original version of the standard, approved for the first time in 1978, has seen 11 published versions to date and now includes more detailed, and sometimes controversial, information, said Bazis.

“We now have safety showers, occupancy allowances and a relief piping formula instead of tables included,” among other changes from the original version, he said. Bazis added that “one of the most fascinating changes [from the original] IIAR-2 is dispersion. They gave an actual GPM for water so you could discharge your emergency ventilation into a water spray to take the ammonia out. We took all that out [of IIAR-2]. The current version has a velocity requirement, spark-resistant construction, and motors out of the air stream. All that stuff we added in there to make the engine room safer.”

IIAR standards also cover growing markets for non-ammonia systems, like CO2, as is the case with IIAR’s CO2 standard, IIAR CO2, which covers safe design, installation, inspection, testing and maintenance and the full lifecycle of CO2 systems, said John Collins, CO2 subcommittee Chair and Director of Industrial Sales at Zero Zone.

Collins said beyond the basics of CO2 systems, IIAR’s standard touches on stationary closed systems, systems using CO2 as a secondary coolant, cascade systems and any system providing refrigeration that is operating part-time or full-time with a transcritical cycle.

IIAR CO2 does not cover: replacement of equipment or piping with functionally identical equivalents; all parts of refrigeration systems or heat pumps that do not contain CO2; factory-built systems, or systems that existed before the effective legal date of the standard.

IIAR recently announced the completion of ANSI/IIAR CO2-2021, Addendum A-2026. This addendum revises Chapter 11 of the original publication and introduces a new set of criteria for determining the capacity of pressure relief valves.

While some standards, like IIAR CO2, aim to include as much different information as possible, others, like IIAR-7 Operating Procedures for Closed Circuit Ammonia Refrigeration Systems, are intentionally streamlined to address the basics of a subject.

“IIAR-7 is our standard for operating procedures,” said Lesley Schafer, IIAR7 subcommittee Chair and Senior Manager, Corporate Refrigeration, for C&S Wholesale Grocers. “This standard lays out what you need in an operating procedure, not how you should write it.”

Schafer said the standard is especially useful for end users, manufacturers and contractors. “We think we know this stuff, but if you don’t stop and think about it once in a while, it’s easy to forget,” she said, adding that the subcommittee’s latest effort on IIAR-7 was to reduce the word count.

“The new thing we did in 2025 was to try to decrease the words in the normative sections, that’s the part [of the standard] that could be enforceable,” she said. Schafer, who is also the subcommittee chair of IIAR-8: Decommissioning of Closed Circuit Ammonia Refrigeration Systems, said the work on this standard is a bit more obscure.

“This is our standard for decommissioning, so one of the things our team found ourselves shaking our heads at was . . . what does that mean exactly?” she said. “This is one case where IIAR-1 is going to have to update with our new definition because we really tried to clarify what we mean by decommissioning.”

“Our main goal with IIAR-8 is to make sure you have a safe sendoff [at decommissioning] so you don’t leave a hazardous situation in a system.”

Finally, IIAR 9: Standard for Minimum System Safety Requirements for Existing Closed-Circuit Ammonia Refrigeration Systems is the standard for the evaluation of existing ammonia refrigeration systems, said Eric Johnston, IIAR-9 subcommittee Chair and Director of Process Safety Management, American Foods Group.

This standard provides the minimum safety requirements for existing ammonia refrigeration systems that are already in operation and may have been built before applicable codes and standards were modified and updated.

“The primary purpose is to offer a structured evaluation methodology so facilities can systematically identify gaps compared to modern expectations,” said Johnston. “IIAR-9 does not replace design standards. Instead, it creates a consistent baseline so that existing systems can be evaluated fairly and without retroactively applying modern requirements unless that’s truly necessary.”

Johnston added that the standard is a good example of how IIAR responds to regulatory pressure via standards. “IIAR-9 was developed in response to lots of end users having ongoing challenges between industry and regulators,” he said. “Agencies frequently attempted to apply other industries’ standards, and they really didn’t apply to our systems.”

While IIAR-9 was written to respond to a specific regulatory problem, it’s also a good example of how IIAR’s standards change as industry needs change.

“Now there’s a lengthy conversation on what the future of IIAR-9 should be,” said Johnston. “With changes in the regulatory landscape, is there really a need for IIAR-9 to remain a standard, or is it better for it to be transitioned into a guideline?”

“We’re ultimately looking to answer that question, and it will be up to the board of directors to give that guidance.”