The most common use for intumescent paint in architecture is to provide an aesthetically pleasing finish on exposed structural steel members.
Typical spray applied fireproofing provides a thick and spongey surface that requires a finished surround to hide and protect the steel member. Intumescent paint provides the same level of protection in a coating that looks like a thin layer of paint.
The paint product is applied to the steel in layers as needed to generate the thickness that corresponds to the level of protection mandated by the building code. A final layer of intumescent paint is mixed with pigments that provide the desired finish color for the steel.
Intumescent products are made of a series of chemicals suspended in a binder. When the binder is exposed to heat it begins to soften, which allows the suspended chemicals to the heat. The chemicals begin to react, which releases vapors that create a foam. A carbonization occurs and the foam solidifies into a black insulating material that is often referred to as char.