Fire Safety Science Digital Archive

Flame arresters have been applied to the protection of industrial equipment which may be used in a flammable atmosphere and which may cause an explosion hazard. The arresters would release pressure resulting from ignition of the gas in the equipment, but would prevent flame emerging through the vents. Cubical enclosures up to 3 ft in volume have been tested, in a propane-air mixture, and were safely protected with commercial crimped ribbon arresters. The vent area required depended on the volume of the enclosure and needed to be sufficient to prevent thermal damage to the arresters. It was usually about 25 per cent of the area of one side of the enclosure. The maximum explosion pressure was low, often less than 2 lb in^-2. The vent area required and explosion pressure could be reduced by distributing the vents on two opposite walls of the vessel. Protection of arresters against mechanical damage was obtained with an external shield. The maximum explosion pressure was related by theory to the vent area and the dimensions of the flame arresters.