Fire Safety Science Digital Archive

Tests have been carried out to determine the nature of relief venting required in a duct containing an obstacle to prevent pressures in propane-air explosions rising above 2 Ib/in2. The tests were carried out in a duct 24 ft long and 1 ft square, the vents being closed either by a loose cover, a polythene film, or a cover clamped by magnets. In general, the provision of relief vents along the duct to the extent of 1 ft2 of vent area for each 6 ft run of duct was sufficient to achieve the above object, although with some obstacles the pressure rose above 2 lb/in2 if the gas was ignited near the obstacle.