The A2L minimum room area calculator determines the smallest floor area (ft²) of a machinery room or occupied space that satisfies the flammable-gas concentration limit for mildly flammable (A2L) refrigerants under IEC 60335-2-89:2019. The method: (1) identify the leakable charge — evaporator pumpdown plus in-room liquid and suction line volume; (2) divide by the LFLroom concentration limit for the selected refrigerant (in kg/m³, from IEC 60335-2-89 Annex GG); (3) divide by the entered room height to get minimum floor area. ASHRAE 15 occupancy classes A (low-density public), B (high-density public), and C (machine room / restricted access) apply different LFL fractions. Supported refrigerants: R-32, R-454A, R-454B, R-454C, R-455A with LFL and molecular weight values per ASHRAE 34-2022.
This tool matters more every year: under the EPA AIM Act (40 CFR Part 84), the interim GWP limit for new commercial refrigeration systems tightened to 700 starting July 27, 2026, pushing manufacturers toward A2L blends like R-454C and R-454A in place of legacy high-GWP HFCs. Foster's engineering team runs this exact calculation on every A2L-charged system before it ships. This is a pre-design screening check; the final safety assessment must be made by a qualified engineer per ASHRAE 15 and your local AHJ.
References: IEC 60335-2-89:2019 §7.4 and Annex GG; ASHRAE Standard 34-2022; ASHRAE 15-2022; EPA AIM Act 40 CFR Part 84.