Tech Rersources

NFPA 285 - The Critical Test for Exterior Wall Assemblies

Why NFPA-285

Fire Safety is an important responsibility of the building designer and owner.  Even if individual elements of a wall assembly are not combustable, the assembly must be tested. NFPA-285 is an important test that measures for vertical and lateral flame spread of the geometry and layers in a wall panel. It's the closest test to real world application in the US.  Engineering judgements and Engineering Evaluations based on NFPA-285 are important part of building code compliance and provide a cost-efficient way to apply the code.  Below on the right are links to three technical papers to help in designing your wall assemblies to meet NFPA-285.


What assemblies need to comply?
Metal wall assemblies containing:

  • MCM panel cladding system
  • Insulated Metal Panel (IMP) cladding system
  • Metal panels using combustible insulation
  • Any wall system that contains a combustible component (beyond a limited class of WRB)
Why is testing the wall assembly important?
• Changing one component can affect results
• Adding components can affect results
• Removing a component can affect results

• Assemblies cannot exceed the tested air gap if combustibles are present (WRB. Foam, Cladding)
• Joint sizing –width and depth considerations can affect compliance
• Joint location, window header and free air cavity are important and can affect flame spread
• Adding fire blocking (NYCBC) can assists in complaince


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