IIAR Hydrocarbon Standards
Tony Lundell presenting at ATMO America 2024.

ATMO America: IIAR to Complete Safety Standard for Large-Scale Hydrocarbon Refrigeration Systems by 2025

The standard applies to R290, R600 and R600a, allowing charges up to 1,100lbs per site for industrial and commercial occupancies.

The U.S.-based International Institute of All-Natural Refrigeration (IIAR) is developing a safety standard for large-scale closed-circuit hydrocarbon refrigeration systems with an expected completion date of 2025 at the latest according to Tony Lundell, Senior Director of Standards and Safety at IIAR.

The Safety Standard for Closed-Circuit Refrigeration Systems Using Hydrocarbon Refrigerants will apply to propane (R290), butane (R600) and isobutane (R600a) refrigerants for industrial and commercial occupancies, outdoor installations and use with secondary fluids. It restricts the total hydrocarbon refrigerants onsite to 1,100lbs (500kg), with the authority having jurisdiction (AHJ) able to approve higher charges.

The Significant New Alternatives Policy Program (SNAP) established under the Clean Air Act provides the framework for the U.S. Environmental Protection Agency (EPA) to identify and evaluate substitutes to replace ozone-depleting refrigerants. Before SNAP can rule on a substitute refrigerant, an accredited entity must develop a safety standard for it.

The EPA’s recently finalized SNAP 26 rule raises the maximum R290 charge in self-contained cases from 150g (5.3oz) to 500g (17.6oz) in cases without doors and from 150g to 300g (10.6oz) for cases with doors. However, for the EPA to establish a new SNAP rule, it first needs a standard to base it on.

“As an ANSI [American National Standards Institute]-accredited developer of standards for natural refrigerants, once the IIAR hydrocarbon standard is completed and approved, we can show the SNAP team that you can safely build a larger [hydrocarbon] system,” said Lundell.

In a policy presentation at the ATMOsphere (ATMO) America Summit 2024 held in Washington, D.C., June 10‒11, Lundell outlined the IIAR’s hydrocarbon standard and provided an update on its recently developed safety standard for closed-circuit CO2 (R744) refrigeration systems. ATMOsphere is the publisher of NaturalRefrigerants.com.

The new standard

Using the authority granted to it under the American Innovation and Manufacturing (AIM) Act, the EPA established a GWP limit of 150 for many types of new refrigeration equipment, with compliance dates starting in 2025. Hydrocarbons, with a GWP of almost zero, offer an efficient and environmentally friendly substitute. However, their A3 flammability rating requires safety regulations beyond those for A2L-rated refrigerants (those with mild flammability). With SNAP 26 only applying to indoor self-contained cases, larger custom-built equipment requires case-by-case approval from local jurisdictions.

Once finished and SNAP approved, the new IIAR standard will “allow hydrocarbon refrigeration to progress in the U.S.” by negating the need for case-by-case approvals”, Lundell said, except when more than 1,100lbs of total hydrocarbon refrigerants are used on one site.

“If you build a system according to this standard, it will be safe,” he added.

The new IIAR hydrocarbons standard will specify minimum requirements for stationary, closed-circuit custom-built refrigeration systems, with specifications covering general and specific design, installation, start-up, inspection, testing, maintenance, decommissioning and common equipment.

According to Lundell, the public review of the first draft of the standard received 161 comments. The committee is currently responding to the comments and “polishing its second draft” for release, which is expected to be released within the next two months. The second draft will be subject to a 45-day public review.

“There’s a minute chance it could be finished and ready for review with the SNAP team at the end of this year, but it will be done no later than 2025,” Lundell said.

In response to a NaturalRefrigerants.com query about the applicability of the hydrocarbon standard in development, Lundell said that it applies to large custom-built systems. However, it will permit the use of off-the-shelf UL or equivalent approved laboratory “listed” equipment as part of a custom-built hydrocarbon refrigeration system, he added.

Propylene (R1270), ethane (R170) and ethylene (R1150) refrigerants are not included in the upcoming hydrocarbon standard, with Lundell noting they are reserved for future revisions. “We are focused on the heavy hitters: R290, R600 and R600a,” he stated.

CO2 standard’s adoption

Just this year, the IIAR’s safety standard for closed-circuit CO2 refrigeration systems, ANSI/IIAR CO2-2021, was approved by SNAP and adopted by the International Fire Code, the International Mechanical Code, the National Fire Protection Association 1 Fire Code and the Uniform Mechanical Code.

“That’s very important for 2024,” Lundell said, adding that as a substitute for ozone-depleting refrigerants, CO2 has “made it.”

“The IIAR CO2 standard harmonizes with the ASHRAE 15 standard, but it goes into further detail outlining cradle-to-grave safety procedures,” he explained, including installation, start-up, inspection, testing and maintenance. Occupancies covered under the CO2 standard include public assembly, commercial, large mercantile, industrial, refrigerated spaces, institutional and residential.

According to Lundell, the hydrocarbon standard follows the scope and depth of the CO2 one. “SNAP’s already approved the CO2 standard,” he said. “We will cover the details and make large [hydrocarbon systems] safe too.”

“SNAP’s already approved the CO2 standard. We will cover the details and make large [hydrocarbon systems] safe, too.”

Tony Lundell, Senior Director of Standards and Safety at IIAR

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