ARLINGTON, Va. — The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) released the results of a research project, “Risk Assessment of Residential Heat Pump Systems Using 2L Flammable Refrigerants.” The study concluded that there is a very low risk of ignition from the use of R-32, HFO-1234yf, or HFO-1234ze in ducted residential split heat pump systems.

“One of AHRI’s core goals is to keep consumers safe when using HVACR and water heating products,” said Stephen Yurek, AHRI president and CEO. “This thorough study found that the ignition risk associated with these refrigerants is significantly lower than with other common hazard events, and is well below the risk level commonly accepted by the public in general.”

The study investigated four locations within a residence for installing the indoor air handler including the basement, garage, attic, and utility closet. Computational fluid dynamics simulation and validation tests were conducted to understand refrigerant dispersion patterns, and the study evaluated seven refrigerant leak scenarios. The fault tree analysis in this study only considered refrigerant ignition and did not determine whether a fire would ensue due to the ignition of surrounding materials. The report is available on AHRI’s website, at www.ahrinet.org/technical+results.aspx.