Testing and selection of fire-resistant materials for spacecraft use

Spacecraft fire-safety strategy emphasizes prevention, mostly through the selection of onboard items classified according to their fire resistance. The principal NASA acceptance tests described in this paper assess the flammability of materials and components under `worst-case' normal-gravity conditions of upward flame spread in controlled-oxygen atmospheres. Tests conducted on the ground, however, cannot duplicate the unique fire characteristics in the nonbuoyant low-gravity environment of orbiting spacecraft. Research shows that flammability and fire-spread rates in low gravity are sensitive to forced convection (ventilation flows) and atmospheric-oxygen concentration. These research results are helping to define new material-screening test methods that will better evaluate material performance in spacecraft.