ASHRAE 15.2-2022

Newly-published ASHRAE Standard 15.2 is a safety standard designed to accommodate the use of A2L-classified refrigerants in low-rise residential applications and is intended for use by manufacturers, installers, contractors, service technicians, building code officials, and others.

Historically, safety requirements were not applied as rigorously to residential HVAC systems as they are to commercial systems, primarily because direct systems were restricted to ASHRAE Standard 34 A1-classified refrigerants and listed to safety design standards such as UL 1995 and UL 60335-2-40, and because the risk of reaching and exceeding a refrigerant's acute toxicity exposure limit (ATEL) in the event of a complete release was very low.

Standard 15.2 requires that all products be listed to a national product safety standard and installed per the manufacturer's installation instructions. Specific requirements are included for which refrigerants can be used, the maximum allowable refrigerant charge, accessories, and interconnecting piping, so that in the event of a full release of the refrigerant charge, the concentration in the space remains safely below the lower flammability limit of the refrigerant.