Development of Prototype Nozzles for Freighter Aircraft Fire Applications

Advisory Circular 150/5210-17B, “Program for Training of Aircraft Rescue and Firefighting Personnel,” added freighter aircraft familiarization as a requirement for Aircraft Rescue and Firefighting (ARFF) training. To develop the tactics and strategies for this training, the Federal Aviation Administration (FAA) requested research in freighter aircraft firefighting. Part of this research entailed developing tactics for extinguishing freighter aircraft fires with an aircraft skin-penetrating nozzle (ASPN). Early in the research effort, it was determined that the current nozzle designs were not adequate to fight cargo fires on freighter aircraft, and a new nozzle design would have to be developed.

Four prototype ASPNs were designed and fabricated specifically to fight cargo fires on freighter aircraft indirectly. Various tests were performed on all four prototype ASPNs to measure flow rates, spray patterns, and extinguishment effectiveness. Flow and pressure readings were taken from each prototype ASPN to confirm that they met industry standards. All prototype ASPNs met industry standards when using the FAA Oshkosh Striker® ARFF research vehicle. Prototype Nozzle 3 exhibited the highest flow rate of all prototype ASPNs, while Prototype Nozzle 4 displayed the highest pressure readings. Photo documentation was taken of the spray pattern for each prototype ASPN to analyze the different spray trajectories each nozzle produced. These trajectories would show where water would go during a container fire. Prototype Nozzles 2 and 3 exhibited similar spray patterns consisting of a wide umbrella spray and a forward-projecting straight stream. Prototype Nozzle 4’s spray pattern consisted of three different range hollow spray cones. Container fire tests inside an aircraft section were conducted to determine the effectiveness of each nozzle. Visual inspection and thermocouple readings were used to determine the effectiveness. Although all prototype ASPNs were able to extinguish a portion of the fire, Prototype Nozzle 3 provided the best design based on these criteria and practicality of nozzle design. Prototype Nozzle 3 was selected to be used for full-scale cargo fires to validate the earlier testing.

DOT/FAA/TC-TN13/11
Author: Jonathan Torres, SRA International, Inc.