Stanislav I. Stoliarov, Qaadir Williams, Richard N. Walters, Sean Crowley, and Richard E. Lyon

The widespread use of brominated flame retardants and fire extinguishing agents in aircraft cabins and recent concerns about their combustion toxicity and environmental impact prompted a study to understand the mechanism by which bromine inhibits the flaming combustion of plastics as a first step towards identifying alternative chemicals or compounds. The heats of combustion of bromine-containing epoxies were calculated from the known atomic composition and compared to measured values in flaming and nonflaming combustion. The heat of flaming combustion was measured in a fire/cone calorimeter (CC) and by burning pyrolysis products in a methane laminar diffusion flame (pyrolysis-flaming combustion calorimetry (PFCC)). Heats of nonflaming combustion were measured by pyrolysis-combustion flow calorimetry (PCFC). The results of these tests indicate that the combustion heat released by these materials decreases with increasing amounts of brominated components as a result of incomplete combustion, char formation, and dilution of the materials with noncombustible bromine. Gas-phase combustion efficiency in the various test methods decreased as: PCFC > PFCC > CC.

Robert I. Ochs

This technical note describes research performed to determine the ignition hazard presented by small fragments of superfine steel wool that contact energized direct current wires in aircraft fuel tanks. Several different methods of shorting a circuit with steel wool were explored. An ignitable mixture of hydrogen, oxygen, and argon, calibrated to have a minimum ignition energy of 200 micro Joules, was used as an ignition detection technique. The electrical currents at the ignition threshold were recorded to determine safe maximum allowable current limits for fuel tank electronics. The lowest current found to ignite the flammable mixture was 99 milliamps (mA); the lowest current found to ignite a steel wool wad in air only was 45 mA.

RGW Cherry and Associates

The objective of this analysis was to assess the number of Serious Injuries and Fatalities that might be avoided from the use of ’16g dynamic seats configured without enhancements to head injury criteria’ and to compare this with the assessed benefit from ’fully compliant dynamic seats’.

John W. Reinhardt

This technical note provides the technical approach and test results of the evaluation of the currently used Federal Aviation Administration certification test, known as the 12-second vertical Bunsen burner test, to certify aircraft ducts and conduits.

Stanislav I. Stoliarov, Phillip R. Westmoreland, Huiqing Zhang, Richard E. Lyon, and Marc R. Nyuden

The applications presented here demonstrate the potential for using quantum chemical methods and molecular simulations to determine the mechanisms and rates of the thermal decomposition of polymers. The expectation is that these capabilities can be used to predict the flammability of materials and develop strategies to improve fire resistance. The thermal decompositions of poly(dihydroxybiphenylisophthalamide) and bisphenol C polycarbonate are investigated by performing density-functional calculations of potential energy surfaces of model compounds representing the polymers. Reactive molecular dynamics, a relatively new technique that extends conventional molecular dynamics to modeling chemical reactions, was used to simulate the thermal decomposition of polyisobutylene. The advantages and limitations of both computational approaches are discussed.