IIAR is moving closer to completing its first standard for hydrocarbons—such as propane and butane—in refrigeration systems and is hoping to release the standard for public review in early 2023.

“It is a complex process to develop a safety standard for multiple applications of a refrigerant of this level,” said Charles Hon, manager, engineering, sustainability, and government affairs, True Manufacturing Co. Inc.

The committee has completed its initial draft and submitted it to the entire hydrocarbon task force for comments. “We’ve addressed those oneby-one and have one set of comments left to address,” said Peter Jordan, senior principal engineer at MBD Risk Management Services Inc.

The task force has also released the standard for a pre-public review to select individuals and the Standards Committee and is addressing those comments. “We are going to a few key players in the industry and letting them see it first. They’re the ones that are coming up with the most beneficial comments,” Hon said.

Trevor Hegg, vice president of product development, industrial refrigeration, and water systems, Evapco Inc., said the goal is to make the public review period more manageable. “When we wrote the CO2 standard, we went through a pre-public review. It really helped bring down the number of comments in the public review because it vetted out a lot of things we weren’t aware of,” he said. “It smooths out the process when the first document hits the streets for public review since it is in better condition and, therefore, receives fewer comments.”

Jordan added that most of the comments received so far have been very useful and very thought-provoking.

Most of the comments so far are dissecting the regulation and comparing it to existing codes and standards. “This standard will have to parallel the ASHRAE 15 standard, which is basically building code requirements used by fire marshals. We’ll have to be in tight sync with it,” Hon said.

Other commenters have asked if it should be broken into sections to make the nearly 400-page document more manageable.


Hon said the committee is targeting early 2023 for a public review period, which could last 30, 45, or 60 days. Then those comments come back to the committee for review and verification.

“The committees work hard to address comments quickly,” Hegg said. “A lot of times the received comments are distributed between the subcommittee members who will look at them and attempt to address them, then the subcommittee as a whole will review each individual member’s suggested response.”

Hegg noted that committees are made up of volunteers who try to move the process along. “We don’t like it lingering. We want to get back to commenters, and we want to get the document published as fast as possible, too,” he said.

Because this is a new standard, it will probably include a second public review. “For a new standard, you sometimes do three or four reviews,” Hon said, adding that hydrocarbons have incredible efficiency potential but also have a lot of safety considerations. “As such, we’re being pretty cautious.

Once the standard is final, IIAR will work with the EPA SNAP group to get approval. “They want a final standard before they will discuss it,” Hon said. “That can take another extended period of time.”

Hon added that many states right now are passing laws that say that any refrigerant that is SNAP-approved can be applied in all applications under building codes. “That will be a major impact. Building codes are often 8-10 years behind the times and would then be overwritten by state law,” he said.


The petrochemical industry has a long history of using hydrocarbons, and they are increasingly being used in some refrigeration applications where other refrigerants are not allowed, are difficult to use, or are inefficient.

For IIAR, developing a hydrocarbon standard was a natural extension of the association’s mission to offer safe practice standards for other natural refrigerants as the use of low globalwarming-potential refrigerants grows. “We’ve been widely recognized for our work on ammonia and recently completed work on CO2. The other natural refrigerants getting attention are hydrocarbons,” Hegg said.

The hydrocarbon standard follows a similar framework as the IIAR CO2 standard with sections on design, installation, startup, inspection, testing, and maintenance, as well as general safety and training needs. Plus, it is a complementary standard to ammonia and CO2.

Hydrocarbons are allowed today in self-contained systems with less than 150 grams of charge per circuit. 150 grams of propane is sufficient to produce approximately ½ ton refrigeration effect. ISO 60335-2-89 covers international requirements for use of HCs in refrigeration systems and has voted to raise the charge limit to 500 grams per circuit in self-contained units with some limitations.

Hydrocarbons are also used in industrial settings, such as refineries or major refrigeration facilities. “Those charge sizes are very large, but getting down to the next major group, such as the grocery stores, requires a new thought pattern because we’ve never had a high-flammability refrigerant used in those applications before,” Hon said. “It is a major step that will have a major impact on how grocery stores are designed and built.”

Hegg said the hope is that a standard will allow systems to expand in size and quantity of refrigerant. “That doesn’t happen unless you have standards in place to help guide people on safe systems,” he said.

Jordan said he expects the use of hydrocarbons to continue to grow and it could work alongside other refrigerants. “The primary refrigerant would be the hydrocarbon, and we anticipate that in certain cases, a secondary refrigerant would be used,” he said.

A hydrocarbon standard is becoming even more critical as the government, industry and private entities address refrigerants. “With all of the changing regulations we’re seeing right now—the AIM ACT reducing HFCs and the global warming discussions from state and federal regulators so the U.S. can meet the Kigali amendment, this is one of the steps that has to be taken,” Hon said. “These are all drivers behind it, and we knew they were coming. Now they are real.”


Hegg said IIAR members are excited about the new standard. “When you think of a 400-page document, there are a lot of people making a lot of contributions to it. It also speaks to the enthusiasm behind it,” he said, adding that the committee has put in a lot of work over the last couple of years.

Even more importantly, natural refrigerants overall are drawing more interest. Hegg added that the standards committee continues to grow, and new members are joining and contributing. “It is exciting to see this level of enthusiasm for natural refrigerants,” he said.