Standard: NFPA 268 – Standard Test Method for Determining Ignitability of Exterior Wall Assemblies Using a Radiant Heat Energy Source

Scope: NFPA 268 measures the ignitability of exterior wall assemblies based on a standardized heat flux exposure. The exposure is specifically calibrated to simulate a specific fire separation distance based on Table 1406. of the International Building Code. If the assembly does not ignite during the 20-minute heat flux exposure, it is approved for the correlated fire separation distance in the field.

Applicable Products: Includes, but not limited to exterior wall claddings, including Exterior Insulated Finishing Systems (EIFS), High Pressure Laminates (HPL), Aluminum Composite Materials (ACM), Wood Composite Claddings, Faced insulation, combustible sheathings, etc.

Test Procedure: A 4 ft. wide x 8 ft. simulated wall assembly is placed in a test fixture and is shielded by a heat sync. A propane-fueled radiant panel is ignited and set at a specific distance from the exterior surface of the test sample based on calibrated values to correlate with a fire separation distance. The heat sync is removed, and the wall is exposed to the heat flux from the burner array. A spark igniter, located 3/8 in. off the exterior surface of the test assembly, cycles on for 5 seconds and off every 2 seconds during the 20-minute exposure. The assembly is observed for ignition during the exposure. If the sample ignites, the assembly cannot be constructed at the fire separation distance it is being evaluated to meet. If the sample does not ignite, the assembly is permitted to be constructed at the fire separation distance that it is being evaluated to meet.

End Result: Pass/Fail criteria. Approval to be used within a specific distance of an adjacent structure.

Intertek Testing Locations: York, PA


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