Tests of Alternative Fire Protection Method for USAF Hangars

摘要

The use of AFFF in overhead suppression systems in aircraft hangars continues to create problems as a result of false discharges and environmental concerns. Two replacement concepts are proposed: the use of water suppression systems to control JP-8 fires and limit fire growth to an acceptable level; and the use of a Mobile Compressed Air Foam Fire Suppression System (MCAFFSS) to protect aircraft in a hangar. Water suppression systems were tested to determine the impact on flame spread and fire growth of the spill fire. The variables investigated included sprinkler application rate and time of sprinkler water discharge. The results showed that the water sprinklers were not capable of preventing flame spread and fire growth on a JP-8 fuel spill. The MCAFFSS unit tested consisted of a premixed AFFF discharged through an oscillating monitor nozzle. Included was a combination UV/IR optical fire detector designed to sense a fuel fire when it is relatively small. Variables evaluated included actuation time, effect of foam aspiration, effect of discharge methods and effect of obstructions. The unit was able to detect and control/extinguish JP-8 spill fires. Tests conducted with obstructions, indicate that obstructions affect the performance of the unit. The technique of targeting the foam at an area in front of the hazard (aircraft) being protected and pushing the foam across the floor, was shown to be the most effective. Non-air aspirated foam was shown to be as effective as air aspirated foam. The location of the fire detector with respect to the fire and obstructions had an effect on detection time.