Abstract
Development and utilization of new refrigerants with zero ODP and low GWP have been required for the global environment protection. Refrigerants that accept these demands（ called A2L refrigerants） have low-flammability, so that the evaluation of fire risk based on conceivable accident scenarios is indispensable. In this paper, ignition hazard of leaked A2L refrigerants by a commercial-use electronic piezo lighter was evaluated in order to assess the fire risk utilizing A2L refrigerants to the commercial-use air conditioning system. R1234yf, R1234ze（E） and R32 were focused as the representative refrigerants of A2L refrigerants. The flammable range of n-butane/A2L refrigerants/air mixture was estimated based on the Le Chatelierʼs law. In the experiment, n-butane/A2L refrigerants/air mixture was piled up in a 1m3-cube pool, and a commercial-use electronic piezo lighter was operated remotely in the pool. Flame propagation of leaked A2L refrigerants was not confirmed in all experimental cases because the ignition energy of mixture should be much larger than that of n-butane and burning velocity is much smaller than the fuel discharging velocity at the outlet of a piezo lighter.
