Preparing for A2L Refrigerants

A refrigerant is a working fluid used in the refrigeration cycle of air-conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulated due to their toxicity, flammability and the contribution of chlorofluorocarbon and hydrochlorofluorocarbon refrigerants to ozone depletion and that of hydrofluorocarbon refrigerants to climate change.

A2L refrigerants are a class of refrigerants that have lower toxicity and flammability than A2 or A3 refrigerants. All common refrigerants are listed through the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) in ASHRAE Standard 34. A2L refrigerants have lower flammability and toxicity compared to other classifications – A = non-toxic, 2 = flammable, L = low burning velocity – making it the second-safest refrigerant category. As of December 2018, more than 68 million air conditioners using A2L refrigerants have been installed around the world.

R–1234yf (Honeywell), R–1234ze (Daikin), R–454C (Chemours), R–455A (Honeywell), R–454A (Chemours), R–454B (Honeywell), R–447A, R–32, and R–452B (Honeywell). As with A1 refrigerants, some A2L refrigerants are pure, and others are blends. The pressure, temperature, and viscosity of A2L refrigerants vary by each refrigerant type.

No, this is not just a phase. Today, more than 80 percent of new vehicles sold in the United States contain an A2L refrigerant. These refrigerants are used in window, room and automotive air conditioners in the U.S., as well as in mini splits, variable refrigerant flow, chillers, hot water heaters and other products around the world. In 2018, 26 million A2L HVAC-R units were sold throughout the world in homes and businesses.

As regulating bodies worldwide impose more stringent standards on the use of high global warming potential hydrofluorocarbon refrigerants, more and more businesses are opting to replace their legacy refrigerants with lower global warming potential solutions. A2L refrigerants allow end users to transition to very low global warming potential solutions and are becoming more widely used in new equipment, while providing favorable performance and operating efficiencies compared to the refrigerants they replace.

Sufficient research has been completed to update safety standards. Over the last decade, nearly $7 million dollars in research investment has been funded by the Air Conditioning, Heating and Refrigeration Institute; ASHRAE; the U.S. Department of Energy; and the California Air Resources Board to research low-global warming potential refrigerants with respect to safety. Just like smoke detectors that have been in use for decades, the science and engineering community will continue to research ways to improve systems related to A2Ls. Other research is underway to summarize available data regarding combustion products to better respond to requests for that data. Like all refrigerants, specific codes and standards apply to A2Ls.