Understanding NFPA 285 Pass/Fail Criteria

September 6, 2021   -  

NFPA 285 determines the flammability characteristics of the exterior, non-load-bearing wall assemblies/panels, and the combustible components within wall assemblies/ panels of buildings that are required to be of non-combustible construction. The test utilizes a large two-story fire test apparatus with gas burners in the lower-story room and adjacent to a lower-story window opening.

The performance of the exterior wall is determined on the basis of visual observations both during and after the test in conjunction with the temperature recorded. The exterior wall is considered as passing when the performance criteria specified below are met during the 30-minute fire exposure.

Flame Propagation: Exterior Face of Test Specimen

Flame propagation on the exterior face of the test wall shall not occur either vertically or horizontally beyond the area of flame plume impingement by the window burner flames. Flame propagation shall be determined to occur if any one of the following conditions is measured or observed:

  • A temperature of 1000℉ (538℃) is measured by any one of the specific exterior face thermocouples.
  • Flames emitting from the surface of the exterior face of the test wall reach a height of 10 ft. (3.05 m) or greater above the top of the window opening.
  • Flames emitting from the surface of the exterior face of the test wall reach a horizontal distance of 5 ft. (1.52 m) or greater from the vertical centerline of the window opening.

Vertical or Horizontal Flame Propagation: Combustible Components and Insulation

Flame propagation shall not occur either vertically or horizontally through the combustible components or the combustible insulation installed within the test specimen, as determined by temperatures measured by specific test wall thermocouples.

Temperatures in Second-Story Test Room

Temperatures measured 1 in. (25 mm) from the interior surface of the test specimen within the second-story test room shall not exceed 500℉ (278℃) above the ambient air temperature at the start of the fire test.

Flames in Second-Story Test Room

Flames shall not occur in the second-story test room.

Flame Propagation to Adjacent Horizontal Spaces

Flames shall not occur beyond the intersection of the test wall and the sidewalls of the test apparatus.

NGC Testing Services offers a wide range of full-scale fire tests, including NFPA 285. Let us know if we can answer any additional questions or provide assistance in your future testing needs.

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