"Fuel tanks." . . "Aircraft equipment." . . "Polymer Chemistry." . . . . . . . "Flame arrestor experiments were conducted with reticulated polyurethane foam materials which are currently being used for fire protection in fuel systems of military aircraft. The flame quenching effectiveness of the 20 pore/inch material was examined in both small- and large-scale flame propagation experiments under various temperature and pressure conditions."@en . . . . . . . . . . . . . . . . . . . . . . . "Evaluation of flame arrestor materials for aircraft fuel systems"@en . . . . . . . . . . "Experimental data are presented from small-scale and full-scale experiments on the flame arrestor effectiveness of polyurethane foam material with 10 pores/inch. Tests conducted which verified the effectiveness of a the 10-pore/inch material for use in at least a fully-packed aircraft fuel tank configuration at atmospheric pressure conditions. In addition, various flame arrestor void configurations designed for external and integral fuel tank applications were examined with near-stoichiometric n-pentane or n-butane and air mixtures at various pressures (0 to 20 psig) and ambient temperature conditions. In the small-scale experiments conducted with cylindrical arrestor segments, the effectiveness of the candidate arrestor material was influenced by variations in the diameter of the test vessel, arrestor length (l2), flame run-up distance or ignition void length (l1), initial combustible mixture pressure, and fuel vapor-air ratio. Observed pressure rises at a mixture pressure of 0 psig were generally less than 10 psi at l2/l1 ratios greater than about 1.5; they increased greatly at ratios less than this value."@en . . . . . . . "Miscellaneous Materials." . . "Porosity." . . "Incendiary ammunition." . . "Physical properties." . . "Chemical properties." . . "Test methods." . . "Tracer ammunition." . . "Aviation safety." . . "BUREAU OF MINES WASHINGTON DC." . . "Fire safety." . . "Flame propagation." . . "Flame arresters." . . "Expanded plastics." . . "Fuels." . . "Air." . . "Pressure." . . "Butanes." . . "Stiffened cylinders." . . "Explosions." . . "Spark ignition." . . "BUREAU OF MINES BRUCETON PA EXPLOSIVES RESEARCH CENTER." . . "Alkanes." . . "Aircraft." . . "Temperature." . . . . "Mixtures." . . "Scale." . . "Hazards." . . "Fuel systems." . . "Vapor pressure." . . "Fire resistant materials." . .