1 Scope
This Technical Specification provides a method to determine the oxygen concentration threshold when a material exposed to a standard ignition source self-extinguishes at a given constant total pressure, temperature, convective flow, and gravity-level conditions. The method can also be used to determine other flammability limits, such as the total pressure or forced convective velocity thresholds, while maintaining other test conditions constant. The flammability thresholds can also be determined with alternate pass/fail criteria, sample configurations and/or size, ignition mode, etc. to allow correlations with test data obtained, for example, under microgravity or reduced-gravity conditions which may have limited testing time in ground experiments.
NOTE The method described provides an assessment of the flammability of aerospace materials under laboratory conditions only. Nevertheless, the results may be used as elements of a fire risk assessment which take into account all the pertinent factors for an assessment of the fire hazard in space systems. Studies on parametric effects have been initiated to better understand the applicability of the data.[8]