Development of an Improved Fire Test Method and Criteria for Aircraft Electrical Wiring

摘要

The Federal Aviation Administration (FAA), as part of its hidden in-flight fire mitigation program, developed an improved flammability test method for aircraft electrical wiring insulation materials (including jackets and other wire protective materials). A comprehensive fire test research and development (R&D) project was conducted on aircraft electrical wiring insulation materials in an effort to continue mitigating the threat of in-flight fires. Previous work at the FAA and the National Fire Protection Association have indicated that the current FAA-required 60-degree Bunsen burner test for electric wire was inadequate to qualify wire when bundled and subjected to a severe ignition source. A literature search and in-house fire tests were conducted during this effort. The results of the literature search indicated that there was no small-scale flammability test standard available that considered radiant heat and wire bundling in its specifications or acceptance criteria that included burn length and after-flame extinguishing time; therefore, an improved flammability test standard for aircraft wiring was required. In-house fire tests were conducted to develop an improved flammability test and provide support data; tests included the current FAA-required 60-degree Bunsen burner test, the microscale combustion calorimetry test (ASTM D 7309-07), the thermogravimetric analysis (ASTM E 2550-07), the intermediate-scale fire test, and the radiant heat panel test. From this R&D effort, an alternative radiant heat panel test method was developed. This method was effective in evaluating the in-flight fire resistance qualities of aircraft electrical wiring insulation.