Intumescent Paint Systems

Intumescent paints are considered the lightest form of passive fire protection. An intumescent is a coating that, when exposed to heat, is rapidly transformed through sublimation, and expands many times its original thickness (up to 100 times), to form a stable, carbonaceous char.

The resultant char reduces the conduction of heat from the fire to the substrate, delaying the time it takes to reach structural failure. This carbonaceous char must have the ability to remain in situ during any movement of the steel, such as expansion or deflection, until the required protection criteria is achieved.

Intumescent paints are typically applied using airless spray paint equipment for speed and quality of finish, whilst some brands might require large plural spray equipment, although brush and roller applications may also be used. Depending on the project specification, which is usually up to 120 minutes, the vast majority of the intumescent materials in the market would need several coatings to be applied in order to reach the required dry film thickness to protect the structure from failure.