NFPA 285: Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components
Standard: NFPA 285 – Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components
Certification Required: Third-party certification is not required in the Code
Scope: NFPA 285 evaluates flame propagation of exterior wall assemblies. Between temperature data and physical observations, it is determined if an assembly can inhibit flame spread from the point of origin during a standardized interior/exterior fire exposure.
Applicable Products: Any combustible (does not meet ASTM E136) material within an exterior wall assembly, save for specific water-resistive barriers (WRB’s) with specific ASTM E84 and ASTM E1354 requirements, are required to be tested to NFPA 285 if the intended structure is greater than 40 ft. above grade. Any exterior wall assembly of any height that contains foam plastic is required to meet NFPA 285 performance.
Test Procedure: A 14 ft. wide x 18 ft. high wall assembly, mimicking field installation practices, is constructed in a mobile test frame. The assembly contains a 78 in. wide x 30 in. high opening centered on the assembly’s vertical centerline with the finished sill height located 30 inches above the test fixture’s first floor. During construction, the assembly is instrumented with thermocouples at specific locations in each applicable air cavity space and combustible component cores. Upon completion of the wall construction and instrumentation, the mobile test frame containing the wall assembly is placed against the test apparatus. The interior first-story burner is ignited, followed by the exterior burner 5 minutes into the test. During the 30-minute exposure, data is collected for each thermocouple and visual observations are taken on flame propagation from the point of origin. Once the burners are extinguished, the thermocouple data is evaluated to determine if critical temperatures were exceeded, thus indicating flame propagation within the wall assembly.
End Result: Pass/Fail requirements of flame propagation on the exterior surface, within the air cavity spaces and combustible component cores, we well as from floor to floor of the test fixture.
Intertek Testing Locations: York, Pennsylvania and Elmendorf, Texas
NFPA 285 - 2023 Edition: An Overview of the Changes
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