Clean Hydrocarbon Refrigerant Explosion Hazards

Explosion hazards are fire safety concerns resulting from the development of clean hydrocarbon refrigerants (environmental friendly flammable refrigerants) to reduce the emission of substances with high global warning potential. Several clean hydrocarbon refrigerants are flammable with propane. Explosion hazards due to flammable refrigerant leakage from refrigerators put inside a small cupboard may give a concentration higher than its lowest flammability. A small amount of ignition energy can ignite the flammable gas to give combustion. Limiting the pressure development in a small cupboard will result in deflagration, and then transition to detonation. Since the compositions of many of environmental friendly flammable refrigerants are not disclosed and odourless, it is very difficult to assess their hazard upon leakage. This study reveals that the hidden hazard of environmental friendly flammable refrigerants would lead to serious consequences using earlier experimental studies on explosion. This is a big problem taking time to solve. Indoor aerodynamics would affect the mixing between leaked refrigerant with air in the room. Appropriate ventilation should be provided to avoid keeping the heavier explosive gas at lower levels. Different ventilation modes with air inlets and outlets at high and low positions should be considered. Use of environmental friendly flammable refrigerants and the ways in protecting against possible explosion hazards for refrigerators commonly put in kitchen cupboards in small rooms, inter alia, economy-class hotel rooms, small apartments, or subdivided units in densely populated cities, such as Hong Kong have to be watched. At the moment, fire safety management must be enhanced to address the problem.