The projected increasing market share for flammable refrigerants has industry experts closely examining safety issues and options. A newly established subcommittee of the U.S. Air-Conditioning, Heating and Refrigeration Institute (AHRI) will conduct a research review of refrigerants that ASHRAE designates as 2L, or mildly flammable.

These include emerging HFO (hydrofluoro-olefin) refrigerants, which are a low-global-warming-potential (GWP) alternative in response to the phase-out of CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons) and moves to phase down the use of HFCs (hydrofluorocarbons).The subcommittee has now been tasked with gauging the comparative risks of 2L and conventionally used refrigerants.

An A2L classification indicates that the substance has low toxicity and burns at a velocity no greater than 10 centimetres or 3.9 inches per second, while B2L refrigerants — typically ammonia — are mildly flammable, but highly toxic. Other hydrocarbon-based low-GWP refrigerants such as propane or iso-butane are classified A3, or highly flammable, and burn many times faster.

“The industry needs to develop a complete list of research needs in order to provide the scientific results necessary to support the safe use of flammable refrigerants in the future,” says Xudong Wang, AHRI’s director of research. “AHRI will play an important role by establishing collaboration within the industry and among relevant organizations, and by conducting research and publishing relevant results.”

The subcommittee includes representation from the refrigeration/air conditioning industry, the commercial and residential buildings sectors, flammability and fire safety experts, and standards and codes developers.