Studies of Mechanical Foams for Aircraft Crash Fire Extinguishment.

Abstract : A basic investigation has been made toward determining the optimum characteristics of mechanical foams used in aircraft crash fire fighting. The work was started on a laboratory scale gasoline fire and then advanced to a 400 sq. ft. gasoline area using special versatile foam generating equipment and spreading nozzles. An analysis of the fifty-seven test fires is presented using radiation detection apparatus, visual observation, and photographic methods as a basis for evaluation. Foams of expansions 4 to 16 were used holding the rate of water application constant at 0.10 gpm/sq. ft. throughout. The factor of foam viscosity or stiffness was also introduced by varying the Drainage Times over a wide range at each expansion. It was concluded that protein-type foams of expansion 10 to 12 were superior in quick extinguishing ability thus permitting early rescue attempts. The 'burn-back' resistance of these foams were also shown superior.