Heating of Printed Circuit Board, Wire Insulation and Electronic Components for Fire Signature Sensor Evaluation

This paper describes the results of tests to identify optimal chemical markers for augmenting particle-based fire detection methods. The tests were conducted at the NASA Glenn Research Center’s Gases and Aerosols from Smoldering Polymers (GASP) facility, a custom 326 liter smoke chamber designed for containing smoke resulting from the heating of materials in a tube furnace. Materials used in this investigation included blank printed circuit boards, polyvinyl chloride and polytetrafluoroethylene/polyimide wire insulation, and various surface mount electronic components used intact to simulate realistic fire scenarios. Two different heating rates were applied during the testing of each set of fuels. A commercially available smoke detector and hand-held chemical monitors were located inside the smoke chamber. Instruments for smoke particle characterization and a Fourier transform infrared spectrometer were plumbed from the outside of the smoke chamber. The time response of the commercially available smoke detector was compared to the time response of chemical monitors and an optical acid gas monitor while heating the material at slow and fast rates. Of particular interest was the dependency of the acid gas product concentrations on the heating conditions and sample material. Results are presented and discussed along with implications for spacecraft fire safety and design of future combustion product monitors.