Flame Arrestor Materials for Fuel Tank Explosion Protection

An investigation was conducted to extend the data on the flame arrestor effectiveness of reticulated polyurethane foams proposed for explosion protection of aircraft fuel tanks. Foams of 10, 15, 20, and 25-pore/inch were evaluated in small- or large-scale experiments using various arrestor packing configurations. Results from small- scale experiments indicated that the ability of the foams to suppress n-pentane- air explosions does not vary noticeably when the foam bulk density is reduced from 1.86 lb cu ft to 1.35 lb cu ft. Other light-weight arrestors that were evaluated included crimped or honeycomb aluminum and Nomex materials which proved to be more effective than 10 ppi polyurethane foam. Large-scale gun-firing experiments made in a 74- gallon fuel tank showed that a cored arrestor model of the dry 20-pore/inch polyurethane foam, having 2-inch diameter cores, can be a suitable design configuration for integral fuel tank applications at pressures up to 5 psig.