With the completion of IIAR-2, the most comprehensive standard for the safe design of closed-circuit ammonia refrigeration systems, the International Institute of Ammonia Refrigeration has written a single authoritative source document that provides a path forward for the ammonia refrigeration industry.

For the first time, model code-writing bodies have a single standard that comprehensively addresses ammonia refrigeration, an important step that will open new possibilities for the use of ammonia as a refrigerant, and lay the foundation for the growth of the industry in years to come.

In addition to providing a single information source for code-writing bodies, the all-new IIAR-2 standard gives regulators, such as the Occupational Safety and Health Administration, and the Environmental Protection Agency, a more comprehensive guideline to the generally accepted good engineering practices (RAGAGEP) of the industry for new system designs. This is expected to enhance the industry’s relationship with regulators.

The new IIAR-2 standard is already being widely adopted by codewriting bodies.

“Getting IIAR-2 adopted by reference by the model codes puts IIAR2 in the position of being a legally enforceable document,” said Jeff Shapiro, IIAR’s code consultant. “With IIAR-2 serving as a comprehensive regulatory document for ammonia refrigeration, IIAR’s technical experts are in a better position to manage our industry’s regulatory affairs, versus relying on others who are not focused on ammonia.”

The revised standard addresses the industry’s advances in technology, incorporates new design approaches and tells users what they need to do in addition to how to do it. Shapiro said the new IIAR-2 is the premier document governing the ammonia refrigeration industry. “It certainly is the most comprehensive in terms of the scope,” he said.

The updated IIAR-2 standard covers all aspects of ammonia refrigeration safety, such as the application of systems, where ammonia equipment can be housed, and how safety standards should be applied to different applications, said Bob Czarnecki, chairman of IIAR’s Standards Committee.

Eric Smith, IIAR vice president and technical director, said the new IIAR-2 integrates topics that were found in other standards but had not previously been included in the IIAR-2 standard. “Essentially a gap analysis was done that compared the International Mechanical Code, Uniform Mechanical Code, the International Fire Code, the International Mechanical Code and ASHRAE 15 with the prior edition of IIAR-2. We addressed or attempted to address those things that were in other codes and standards but weren’t in IIAR-2,” Smith said. Dave Rule, president of IIAR, said, “We wanted to make sure the rewrite of the standard addressed some of the important issues that were going on in refrigeration today and to make sure we had a comprehensive safety standard for our industry.”

As Czarnecki put it, “The whole purpose was to create a comprehensive, safe-design document for ammonia refrigeration. In addition to featuring new information, IIAR-2 was reorganized to make it a much more workable document. “It was divided into chapters to make it an easier document to work with and much simpler to access information,” Rule said.

“We wanted to make sure the rewrite of the standards addressed some of the important issues that were going on in the refrigeration industry and to make sure we had a comprehensive safety standard for our industry.”

– Dave Rule, president of IIAR

Dave Schaefer, chief engineer for Bassett Mechanical and chair of the subcommittee for IIAR-2, said that now individual chapters separately address specific pieces of equipment. “Before, multiple types of equipment would appear in one chapter. It made much more sense to separate it into system components,” he said.

One of the most significant changes was the inclusion of an informative appendix – Appendix A, said Tony Lundell, director of safety and standards for IIAR. The main document had to be written with enforceable language in order to be adopted by the code bodies, but Appendix A allowed IIAR to include additional, informative explanatory material on the normative— mandatory— requirements found in the main body of the document.

“In an enforceable standard or code, you can’t write descriptive information into an enforceable text,” Shapiro said.

“To enhance the usability of the document, Appendix A clarifies things in layman’s terms,” Lundell said, adding that agreeing to provide an informative appendix was a major breakthrough. “That was a landslide that allowed the people on the code language side to say ‘we’re going to get it written in the code language’ and the people on the explanation side who wanted the informative language to get that too, so it was easily digestible.”

Smith said Appendix A also helps users understand why certain provisions were included and how to apply them.


IIAR-2 includes about a dozen changes that were made to coordinate with associated model codes, Czarnecki said. “They are good changes that allow us to mold our document more into what we would like to see it become.”

Shapiro said, “IIAR-2 was written previously as a design standard. The objective of IIAR for the rewrite was to expand the scope of IIAR-2 to become a comprehensive document that combines features of a code with features of a standard. Codes typically tell you what to do, and standards typically tell you how to do it. The new IIAR-2 does both.”

In developing the standard, IIAR staff also worked directly with OSHA, meeting with the agency several times. “OSHA had certain issues they wanted to get clarity on, so the standard addressed practices that could help to prevent certain situations from occurring,” Lundell said.

OSHA was particularly interested in portions of the standard that address packaged systems as well as ammonia refrigeration equipment in areas other than machinery rooms. “OSHA was thankful that we are getting the information into a standard we can use,” Lundell said, adding that while OSHA did not comment on the standard formally, the agency did provide some feedback throughout its development. The agency was particularly in favor of consolidated requirements, he added.

“IIAR-2 has the capability of standing on its own without relying on a code, but it has been written in a way that allows it to work hand-in-hand with the building, mechanical and fire codes that are used by jurisdictions throughout the U.S.,” Shapiro said.

Rule said the standards writing process at IIAR follows the American National Standards Institute consensus method, which includes input from manufacturers, engineers, end users and educators. “It ultimately ensures that IIAR-2, as well as IIAR’s other standards, are recognized by the regulatory agencies—OSHA, DHS, EPA and the code bodies around the country.”

The consensus body for IIAR-2, which included 28 members, was a balanced interest group, but Shapiro said it is important to remember that consensus doesn’t equate to unanimity. “There are often dissenting opinions in a consensus decision, but isn’t a disadvantage. On the contrary, it demonstrates the broad perspective and input involved in the decision making process, and that was certainly the case with IIAR-2” he explained.


As technology has changed, so has the placement and use of the refrigeration equipment and components the industry relies on. For that reason, one of the first goals of IIAR-2 was to create a standard that reflected current practices in ammonia refrigeration.

For the first time in the industry, the IIAR-2 standard broadly addresses ammonia equipment outside of machine rooms in industrial settings.

“Typically everything but evaporators had to be in a machine room, but a lot of processes require equipment to be out on the floor,” Czarnecki said. “One of the things that was never allowed on the floor was an ammonia pump. Now there are pumps that don’t leak and have safeguards, which we’ve termed low-probability pumps.”

The standard also addresses lowcharge, small package systems. “There is a whole chapter on packaged equipment, which is a new topic for this standard,” Czarnecki said, adding that IIAR-2 is the first standard that specifically addresses packaged ammonia equipment. “Packaged equipment has been around forever but now it has gone main stream, so we dedicated a chapter to it.”

Lundell said, “For years, businesses have been installing equipment outside of machinery rooms, but standards did not address this situation. The new IIAR-2 includes a full chapter on equipment outside of machinery rooms.” Now, the practice is specifically allowed if precautions are taken.

IIAR-2 also eliminates the need for direct outside egress for machine rooms, which allows companies to place a machinery room in the center of a building if necessary and not require them to have a direct outside wall. Smith said, “Now they can safely house refrigeration equipment next to production equipment.”

The standard also discusses requirements for outdoor installations. “It is a practice that people have been following for a long time, but standards never clarified the questions of if outdoor installations are acceptable and under what conditions,” Smith said.

The updated IIAR-2 includes a chapter on ammonia detection and alarms, standardizing their system response functions, and revisits the question of “shunt-tripping,” or the de-energizing of electrical equipment in the presence of large concentrations of ammonia. “IIAR-2 addresses this in Appendix M. No one wanted to make it a mandatory requirement, but the informative appendix provides guidance on shunt tripping and operational containment and explains what you can do,” Czarnecki said.


IIAR-2 also added some definitions for certain terms, such as combustible material, trained operators, public access and public assembly. IIAR-2 includes further clarification on pipe terminations, seismic bracing, text to be included on signage, labels and pipe marking, and the minimum size for relief connections, Smith said. “It is important to understand what the body of the standard is discussing,” Smith said.

“It is also important that when there are questions of code compliance, you have a definition that will, as clearly as possible, provide an explanation of what you are talking about, so there is less room for interpretation.”

An important direct change related to safety is the minimum pressure for low-side vessels, Smith said, adding that it has been raised to 250 PSIG from 150 PSIG.

Requirements for alarms have also changed. Lundell said “In the machinery rooms, the biggest change is with the detection level that triggers ventilation. If you’re below 25 parts per million, you do not need to alarm. Maintenance can often release minor amounts of ammonia e.g. you may be changing coalescent filters on a twin screw compressor, and there is no need to alarm in these cases. Once a 150 ppm is detected, it shall activate your emergency ventilation system. It used to be it would not activate until 1,000 ppm was detected.”

Schaefer added that ventilation requirements are divided into different segments: temperature control ventilation, fresh air ventilation and emergency ventilation. Ventilation for occupant fresh air was added as a new segment.

As part of the updated standard, there is now a requirement to consider functional testing in the design of the system. “What that means is the system designer needs to think about and incorporate provisions into the system so it can be functionally tested,” Smith said.

Smith also said that IIAR-2 mandates the consideration of worst-case scenarios of over-pressurization for vessels and heat exchangers. “For example, there are scenarios when equipment is cleaned that could produce an over-pressure situation. We’ve added a lot of ways to determine these scenarios,” Smith said.


Including pre-public review discussions, pubic review comment breakout sessions and conference call team meetings for the development of comment responses and document drafting, this IIAR-2 revision required hundreds of meetings to get it finalized, approved and published. The Standards Committee addressed hundreds of public review comments, creating a change to the draft or an explanation for each concern submitted.

Even though the most recent version of IIAR-2 has just been released, IIAR and its members are already working on improvements, which have been ongoing since IIAR-2 was originally introduced to the industry in 1974. The original standard was ANSIapproved in 1978 and has been going through a rewrite every five years or so. “It is all done to address existing designs, to improve the systems and meet our mandate to operate safely as an industry,” Rule said.

Schaefer said those involved with the current rewrite have kept a running list of items to explore. “One of the things that will be addressed in the future is one or several provisions for high pressure cut-off testing on compressors,” he said.

The current document lays the groundwork for the future, Czarnecki said. “We brought into play and started to mention things like automatic controls that were never mentioned before. We didn’t say a lot about it, but we got the ball rolling.”

Rule said the committee will start an earnest rewrite process in about two years. “If there is anything critical that needs to be addressed sooner, there are processes we can follow to address those and present an addendum to the standard.”

Shapiro said, “Codes and standards are never perfect. That is the reason we have a process by which we continually update them. Technology changes. People’s understanding of how to use technology changes.”

For now, IIAR’s Rule said the organization would be focused on informing members and the industry at large on the technical details and widespread implications of the newly released standard.

IIAR announced that it is planning a special education program on Sunday, March 20, ahead of the IIAR 2016 Annual Conference and Exhibition. The program will provide an overview of the new, final IIAR-2 standard, including new areas of interest and changes to the standard that will have a major impact on the industry today, Rule said. He added that IIAR members may register online and learn more about the upcoming educational session via the IIAR website.

“IIAR-2 represents the culmination of some of the most important and vital work our organization has had the opportunity to complete in recent years,” Rule said. “This standard truly lays the foundation for the future of our industry. IIAR’s upcoming educational session will be the first step for many in our industry as we begin the process of putting it to work in our day-to-day operations.”