Intumescent

Intumescent is a substance that will expand because of heat exposure (generally fire), increasing in volume whilst simultaneously decreasing in density.

By swelling, the substance forms a char which seeks to either encase the material it’s applied to, thus protecting it from damage, or expand to fill any voids with a protective char, preventing the passage of fire through a fire-separating element.

Intumescent can be broken down into types:

• Soft char
• Hard char