The U.S. Environmental Protection Agency (EPA) recently published a final rule and proposed a new rule that would allow the use of A2L refrigerants in some new air conditioning and refrigeration equipment.

In September 2022, the EPA proposed adding several new low-GWP refrigerants to its Significant New Alternatives Policy (SNAP) program for some comfort cooling and refrigeration equipment. In April 2023, EPA finalized the rule — known as SNAP Rule 25 — which lists seven refrigerants as acceptable, subject to use conditions, or acceptable, subject to narrowed use limits, in the refrigeration and air conditioning sector (see Table 1).

The rule also modifies a use condition for the listing for HFC-32 used in the refrigeration and air conditioning sector. EPA previously found the refrigerant HFC-32 acceptable, subject to use conditions, in new self-contained room air conditioners and heat pumps in SNAP Rule 19. This final rule modifies those use conditions to be consistent with use conditions applied to other refrigerants with similar flammability, as finalized in SNAP Rule 23.

The use conditions address safe use of flammable refrigerants and allow manufacturers to use either UL Standard 60335-2-40, 3^rd Edition or UL Standard 484, 8th Edition, a legacy standard that UL will sunset on January 1, 2024. Beginning January 2, 2024, manufacturers must meet the requirements in UL Standard 60335-2-40, 3^rd Edition. This updated use condition will apply to new equipment manufactured after the effective date of this final rule.

In another change from the proposed SNAP 25 rule, EPA decided not to establish a new non-residential dehumidifier end use. This change only affects whether a new category is established, not the overall acceptability of HFC-32 for use in non-residential dehumidifiers. After review of the comments received, EPA is clarifying that dehumidifiers for non-residential use fall under the Residential and Light Commercial Air Conditioning and Heat Pumps end use. EPA noted that all previously listed substitutes in this end use, including HFC-32, will apply to non-residential dehumidification equipment.

SNAP Rule 26

In the proposed SNAP Rule 26, which was released in May 2023, 10 refrigerants would be listed as acceptable, subject to use conditions, in the refrigeration and air conditioning sector (see Table 2). This rule has been eagerly anticipated by commercial refrigeration manufacturers, many of whom have expressed concern that some equipment does not have a clear path to compliance with the deadlines in the AIM Act.

In addition, SNAP Rule 26 proposes modifying use conditions for the A3 refrigerant, R-290 (propane), in certain refrigeration end uses. EPA previously listed R-290 acceptable, subject to use conditions, in new self-contained commercial ice machines and stand-alone equipment in SNAP Rules 21 and 17, respectively. This proposed action would modify those use conditions to reflect the UL Standard 60335-2-89, 2^nd Edition, in place of UL Standards 563 and 471, and would apply to equipment manufactured after the effective date of a final rule based on this proposal.

The EPA is also proposing to exempt R-290 from the Clean Air Act section 608 prohibition on releases of refrigerant during installing, maintaining, repairing, or disposing of refrigerated food processing and dispensing equipment. This exemption is based on the EPA's assessment that the release of R-290 in such scenarios is unlikely to pose a significant environmental threat.

Once SNAP Rule 26 is published in the Federal Register, the public will have 45 days to submit comments at www.regulations.gov, Docket Number EPA-HQ-OAR-2023-0043.