Fire retardant coatings are used to bring
building and construction materials into compliance with Federal,
State and local building code requirements. The coatings must
be fire tested and rated for their ability to retard ignition
and flame spread. Both the coatings and the testing agency must
be approved by building code officials.
Most fire retardant coatings work by suppressing
flame through intumescence, which means they puff up on exposure
to flame or excessive heat, solidifying into a foam. This foam
insulates the substrate from the flame.
Fire retardant coatings reduce flame spread
on the surface of a material. Fire retardant coatings are tested
in a fire test chamber using ASTM Method E 84, "Standard
Test Method for Surface Burning Characteristics of Building Materials."
ASTM Method E 84 is used for testing of interior building materials,
not those used on the exterior of buildings. This method requires
that a 25 foot panel of the substrate coated with the fire retardant
coating be exposed to flame for ten minutes. The retarding of
flame spread and smoke development are measured, and the coating
receives a flame spread rating equating to Class I, II, or III
Building Material Qualified by:
Class Flame Spread Index