George B. Geyer, Lawrence M. Neri, & Charles H. Urban

Small-scale experiments were conducted to determine the effectiveness of crushed and graded stone aggregate in preventing or retarding the rate of flame propagation from a fixed-ignition source when it was employed as a simulated ground cover material under controlled experimental conditions, for each of three aviation fuels. Tests included the use of loosely packed aggregate and no-fines concrete made with the same material. No significant difference in the rate of flame spread was noted between the loosely packed aggregate and no-fines concrete under equivalent test conditions. The experiments showed that the effectiveness of a point of the hydrocarbon fuel and of its depth below the surface of the simulated ground cover. The fire suppression and/or containment effectiveness of the ground cover materials increased as the size of the aggregate decreased and the flash point of the fuel increased and as the depth of the fuel below the surface of the stone increased.

Richard G. Hill

Tests under simulated flight conditions were conducted on a Self-Generating Overheat Detection System installed in a C-140 airplane engine nacelle. They were run with the system in its normal configuration and also with a section of the detection cable pinched, opened and shorted. The system was monitored for fire response time as well as for false alarms.

The system performed well in it normal, pinched and opened configurations, but the alarm time was increased by over 100 percent when the cable was shorted. No false alarms were noted during testing.

John F. Marcy

The study of the flammability, smoke, and toxic characteristics of sir plane cabin materials was first initiated at NAFEC in 1963 following the introduction of large jet air transports to commercial aviation.

John F. Marcy

This document has been prepared to provide management and test personnel with information on the plan of action ANA-420 in response to Request No. AFS-100-73-134 of the Flight Standards Service and ARD-522 Resume 183-522-03X dated March 22, 1973 and forwarded under ARD-1 letter to ANA-4 dated May 9, 1973.

Jack Jones & Constantine P. Sarkos

Theoretical calculations were performed to aid in the design of a perforated tube that will uniformly distribute Halon 1301 throughout the unventilated passenger cabin of a commercial air transport. Conditions for the calculations were those of a passenger cabin of a DC-7 fuselage, with a volume of 4000 cubic feet and a length of 72 feet, being used as a test article for evaluating the performance of such a system. Four separate calculations were made to determine the (1) size and number of orifices in the tube required for various Halon 1301 discharge rates; (2) pressure drop as a function of tube diameter and discharge rates; (3) time required to fill the tube with Halon 1301 for various tube diameters; and (4) cabin temperature and pressure after completion of Halon 1301 discharge. The first calculations indicated that for a given discharge time, the required orifice diameter decreased slightly with increasing orifice number for a large number of orifices (about 40-50). The pressure drop was shown to be a strong function of both tube diameter and discharge time; however, practical tube diameter could be selected to assure a negligible pressure loss – a system feature which allows orifices equally spaced with the same diameter. It was demonstrated that the fill time would be less than 10 percent of most normally used discharge times – another desired system feature. Thermodynamic calculations predicted a 38 degree F cabin temperature after complete discharge of agent with an initial cabin temperature of 70 degree F and relatively humidity of 50 percent.