A2L Refrigerants: Latest Challenges and Opportunities
To facilitate a smooth transition to A2Ls, jurisdictions across the country have already begun adopting the approved 2027 IMC code language addressing these issues. It is highly recommended that all jurisdictions review these sections of code and determine the best method for addressing them in their area.
As the first half of 2025 wraps up, the Heating, Ventilation and Air Conditioning (HVAC) industry wrestles with some of the new updates surrounding A2L refrigerants.
To comply with regulations set by the U.S. Environmental Protection Agency (EPA), manufacturers have made the switch from the higher global warming potential (GWP) HFC refrigerants to new HVAC systems utilizing lower GWP A2L refrigerants for residential and light commercial markets.
The new lower GWP equipment is making its way onto the market, and with it comes some challenges with building code compliance for multifamily construction.
Necessary Changes to Accommodate for A2L Refrigerants
Under the EPA regulations, manufacturers can no longer manufacture or import HVAC systems with GWPs >700 as of January 1, 2025, and the installation of HVAC systems with GWPs >700 is prohibited on or after January 1, 2026.
Nearly all states and local jurisdictions have taken steps to allow the use of A2L refrigerants in residential and light commercial construction, but the changes have not come without some difficulties. While the 2024 International Codes® (I-Codes) and the applicable ASHRAE and UL referenced standards address the use of A2L refrigerants, there were some necessary changes that did not make it into the 2024 International Mechanical Code® (IMC).
Under the 2024 IMC, refrigerant lines for systems utilizing A2L refrigerants that penetrate two or more floor/ceiling assemblies must be located in a ventilated, fire-rated shaft. These requirements, which have been determined to be unnecessary by the ASHRAE 15 standards committee, have had a significant impact on multifamily construction.
ASHRAE has since updated the ASHRAE 15 standard, and during the International Code Council’s 2027 code development cycle, the necessary changes have been approved for the IMC that eliminate these requirements.
Two key changes were approved during the Code Council’s Committee Action Hearing #1 that are now on the Consent Agenda for the Public Comment Hearings to be held next year. The 2027 changes to the IMC are:
- Section 1109.2.5 regulating refrigerant pipe shafts: Exception 2 has been modified such that piping in a direct refrigeration system using any refrigerant meeting the limitations of IMC Table 1103.1 are safe to install without a fire-rated shaft.
- Section 1109.3.2 regulating shaft ventilation: An allowance was added for residential systems to eliminate the ventilation of the shaft when the piping system is continuous without fittings located in the shaft.
To facilitate a smooth transition to A2Ls, jurisdictions across the country have already begun adopting the approved 2027 IMC code language addressing these issues. It is highly recommended that all jurisdictions review these sections of code and determine the best method for addressing them in their area.
For additional information on this topic, please reach out to Jim Cika via email at jcika@iccsafe.org.
For more information on preparing for A2L refrigerants, please click here.
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About the Author
Jim Cika, director, PMG technical resources for the International Code Council, where he serves as a subject matter expert to the plumbing, mechanical, and fuel gas codes. He represents ICC in federal and state coalitions, task forces, committees, and councils where expertise in I-Code subjects is required. Cika has more than 20 years of experience in the manufacturing and construction industry where he has served as chief technical expert for regulatory, product standards, building code and product engineering matters.
