Unlike the last refrigerant transition, in which HCFCs such as R-22 were phased out because they were depleting the ozone layer, this transition is due to the fact that HFCs such as R-410A and R-404A are considered to be contributing to global warming. As a result, there will be a number of low-GWP technologies and solutions introduced over the next few years that HVACR contractors and technicians will need to learn how to safely use.

Safety First

Safety is a big issue with this transition, because unlike the last transition, which moved from one non-flammable (A1) refrigerant (R-22) to another (R-410A), the two low-GWP alternatives that are designated to replace R-410A in air conditioning equipment – R-32 and R-454B – are mildly flammable (A2L). The difference between the two types of refrigerants is that A1 refrigerants do not propagate a flame.

That said, it is very difficult to ignite an A2L refrigerant. These types of refrigerants have a low burning velocity and high minimum ignition energy, which means it takes a strong ignition source to ignite them. AHRI has conducted numerous flammable refrigerant research projects that simulate real-life conditions, and its final report found an inability of most ignition sources to ignite the A2L refrigerants being tested.

It is also important to note that all A2L refrigerants are approved by the EPA’s Significant New Alternatives Policy (SNAP) program. Under this process, EPA considers the safety, toxicity, flammability, and other environmental factors before approving any new refrigerant, and all flammable refrigerants are subject to additional safety requirements. EPA’s SNAP Rule 23 lists six A2L refrigerants, including R-32 and R-454B, as acceptable, subject to use conditions, in new residential and light commercial air conditioners and heat pumps.

Equipment containing A2L refrigerant will likely not be available for another year or two, because with the exception of a few states (only Florida, Oregon, and Washington state at the time of this article), most building codes do not allow the installation of comfort cooling equipment containing A2L refrigerants. Industry experts are hopeful that the 2024 international building code update will include the use of A2L refrigerants.

Once A2L equipment becomes available, technicians will find that it does not differ much from today’s residential and light commercial R-410A units. However, as a designated mildly flammable refrigerant, A2L equipment will contain special features to ensure safe operation, per safety standard UL 60335-2-40, third edition. These features will include special labeling, as well as a refrigerant detection system (RDS), which will be required for all systems in an occupied space that exceed a prescribed refrigerant charge limit.

The RDS is a small device incorporated into the equipment that detects the presence of a specific refrigerant. If there is an A2L leak and the refrigerant concentration passes the predefined threshold, the RDS will communicate that the HVAC equipment should initiate mitigation actions, such as turning on fans and blowers to dilute the refrigerant concentration and maintain a concentration well below the flammability limit.

Uncertain Future

While EPA has delivered its final rule establishing HFC production and consumption baselines, as well as outlined the phasedown schedule, there is more information to come. As part of the rule-making process, EPA granted multiple petitions that seek to further restrict the use of HFCs in air conditioning and refrigeration equipment.

These petitions came from environmental groups, as well as those in the HVACR industry, who, among other things, want to ban the use of R-410A in new residential and commercial air conditioning equipment starting January 1, 2025. That date aligns with California’s HFC phasedown regulations, which require a 750 GWP limit for new air conditioning equipment starting in 2025, while VRF system manufacturers have until 2026 in order to comply with the new limit.

As far as commercial refrigeration equipment is concerned, one of the petitions granted calls for following California’s 150-GWP limit for new or remodeled facilities that utilize equipment containing more than 50 pounds of refrigerant, starting on January 1, 2023 (California’s rule started January 1, 2022). Another petition asked for GWP limits of 1,500 to 2,200, starting January 1, 2022, depending on the type commercial refrigeration equipment.

Now that the petitions have been granted, EPA has two years to propose and finalize rulemakings addressing these petitions. After consulting with stakeholders, EPA expects its “forthcoming rules will provide a clear regulatory landscape that will help the transition” to low-GWP alternatives.

Further changes may also be seen, pending the outcome of litigation. Several industry associations and a cylinder manufacturer have already filed a lawsuit regarding EPA’s final rule decision to ban disposable refrigerant cylinders starting in 2025. Many believe that this will be costly and burdensome to the HVACR industry, which is why HARDI, ACCA, PHCC, and Worthington Industries have filed a petition that asks the United States Court of Appeals to overturn the ban, as well as cylinder tracking requirements contained in the finalized rule.

“HARDI was disappointed by EPA’s overreach in banning single use cylinders and establishing an overly-complicated cylinder tracking system,” said HARDI CEO, Talbot Gee. “HARDI and the rest of the industry want to work with EPA to successfully phase down the use of HFCs, however we cannot stand by as the agency exceeds its authority.”

While the HFC phasedown has officially started in the U.S., there are still many unanswered questions. But the bottom line is that the transition is coming, and the HVACR industry will ultimately move from HFC refrigerants to equipment that contains lower-GWP refrigerants that will likely include mildly flammable A2Ls.