How to Fail the NFPA 285 Test

The June 14 fire at London’s Grenfell Tower apartment complex burned through 24 floors and claimed seventy-nine lives. The rapid spread and magnitude of this incident can be attributed to the combustible cladding used in the exterior construction of the tower.

The implementation and adoption of NFPA 285, Standard Fire Test Method for Evaluation ofthe Propagation Characteristics of Exterior Non-Load-Bearing Wall AssembliesContaining Combustible Components, has largely prevented these fire incidents from occurring in the United States. This standard outlines the requirements and test procedures to determine if a given wall assembly could support a self-accelerating or self-spreading fire up an exterior wall, or spread fire to interior floors above the fire floor.

Any materials intended for use as an exterior wall assembly must pass the NFPA 285 test. The assembly will be considered to have failed if:

1. A temperature greater than 1,000°F at 10’ or higher above the top of the window opening, as measured by thermocouples mounted on the surface of the test specimen.
2. Flames visually observed on the exterior face of the specimen at 10’ of higher above the top of the window opening.
3. Flames visually observed on the exterior face of the specimen at 5’ or further from the centerline of the window opening.
4. Temperature rise greater than 750°F within any combustible wall components more than ¼” thick.
5. Temperatures greater than 1000°F within any wall cavity air space.
6. Temperature rise greater than 500°F in the second story room, measured 1” from the interior surface of the wall assembly.
7. Flames visually observed within the second-story test room.

By examining exterior wall fires around the world, understanding the history and development of NFPA 285, and reviewing the test method, Building Exterior Wall Assembly Flammability: Have We Forgotten the Past 40 Years?, demonstrates how the continued use and enforcement of NFPA 285 is essential in preserving a fire safe America.

WHITE PAPER: Building Exterior Wall Assembly Flammability: Have We Forgotten the Past 40Years?

Why is London Burning?

In the early hours of Wednesday, June 14, 2017, forty fire engines and 200 firefighters responded to a fire in Grenfell Tower.  The fire started on the fourth floor of the apartment complex, and within fifteen minutes had scaled the exterior of the structure burning through the building’s 24 floors.  As of this writing, the death toll has reached seventy-nine with others still unaccounted for.

The rapid spread and magnitude of this incident can be attributed to the combustible cladding used in the exterior construction of the tower. The void space between the aluminum panels and building fabric can create a “chimney effect” allowing fire to rapidly move up the side of a structure.

Within the last year, UK fire officials and experts, issued a report warning of the dangers of buildings being wrapped with combustible materials. The report noted an increase in the use of these combustible materials due to the desire for increased building efficiency, improved thermal effectiveness, and a more aesthetically pleasing appearance.

WHITE PAPER: Building Exterior Wall Assembly Flammability: Have We Forgotten the Past 40Years?

Why is this type and magnitude of fire destruction not happening in the United States? Many years past, the fire engineering community noticed a trend in the increased use of combustible components in exterior construction.  Predicting the fire and life safety issues that this use of construction would present, research was conducted and a test method was developed, NFPA 285, StandardFire Test Method for Evaluation of Fire Propagation Characteristics of ExteriorNon-Load-Bearing Wall Assemblies Containing Combustible Components. This standard outlines the requirements and test procedures to determine if a given wall assembly could support a self-accelerating or self-spreading fire up an exterior wall, or spread fire to interior floors above the fire floor.  Through application and enforcement of this standard, America has been spared the costs and loss of these specific fire incidents.

The future prevention of these incidents, however, seems uncertain.  “Green building” and energy conservation interests have been pushing for reductions to, or elimination of, NFPA 285 testing requirements. The goal of these efforts is to allow “unfettered latitude in the use of plastics in exterior walls”.  Attempts to modify these fire safety requirements in the model codes have been unsuccessful. In Washington, D.C., Massachusetts, Indiana, and Minnesota NFPA 285 testing requirements have been successfully eliminated or reduced, however, through the local code adoption process.

By examining exterior wall fires around the world, understanding the history and development of NFPA 285, and reviewing the test method, Building Exterior Wall Assembly Flammability: Have We Forgotten the Past 40 Years?, demonstrates how the continued use and enforcement of NFPA 285 is essential in preserving a fire safe America.

WHITE PAPER: Building Exterior Wall Assembly Flammability: Have We Forgotten the Past 40Years?