Section 7.4 covers Electrical Wire Insulation Flammability (Test 4) in NASA-STD-6001B. The purpose is to determine whether an electrical wire insulation material, when exposed to a standard ignition source, will self-extinguish and not transfer burning debris which can ignite adjacent materials.
Five test specimens, each having a length of 1.2 m (48 in) with the active area being 300 mm (12 in), are tested one at a time mounted at a 15-degree angle from vertical. Specimens are ignited at the bottom and allowed to burn until self-extinguishing. The burn length and whether ignition of paper occurred by burning debris transfer are recorded.
Acceptance requires: (1) no specimen burns more than 15 cm (6 in), and (2) no specimen propagates flame by transfer of burning debris. Failure of any one specimen constitutes failure of the material. The test method references ISO 14624-2.