As the government and general public focus on energy-efficient building envelopes, the expectation for superior building performance has heightened. Energy regulations and demand for better building envelope performance has resulted in an increased use of polystyrene, polyisocyanurate, and polyurethane foam plastics. Demand for these materials has elevated the importance of complying with NFPA 285—a standard fire test method for evaluating fire propagation characteristics of exterior wall assemblies containing combustible components.
The International Building Code generally requires exterior walls in Types I and II, III and IV construction to be built of noncombustible materials but permits combustible insulation and wall coverings in some cases based on NFPA 285 testing. NFPA 285 determines fire propagation characteristics for post-flashover fires of interior origin, and requires visual observations of flame propagation and assessment of temperature data during the test.