- Direct flame exposure. This test method provides for the direct flame exposure of a wall specimen to a flame source centered at the base of a 4-foot by 8-foot (1220 mm by 2440 mm) test assembly.
- Gas burner. The method employs a gas burner to produce a diffusion flame in contact with the test wall assembly.
- Heat output. The gas burner produces a prescribed net rate of heat output of 8535 Btu/min (150 kW) for a period of 10 minutes, after which the flame exposure is terminated.
- Resistance to fire penetration. The test method measures the ability of the wall system to resist fire penetration from the exterior to the unexposed side of the test assembly under the conditions of exposure. Observations are made for the appearance of sustained flaming or glow on the unexposed side and/or sustained glowing on the unexposed side at the end of a 60-minute observation period.