An intumescent is a substance that swells as a result of heat exposure, leading to an increase in volume and decrease in density. Intumescence refers to the process of swelling. Intumescent materials are typically used in passive fire protection and require listing, approval, and compliance in their installed configurations in order to comply with the national building codes and laws.
A charred marshmallow is a familiar example of intumescence
Low pressure intumescent resin: This product is suitable for use in passive fire protection in general, and in firestopping and interior fireproofing in particular. The small, orange chunk on the bottom right is capable of growing into the large black object above and to its left.
Pipe covered with a thin-film intumescent spray fireproofing
Passive fire protection (PFP) is components or systems of a building or structure that slows or impedes the spread of the effects of fire or smoke without system activation, and usually without movement. Examples of passive systems include floor-ceilings and roofs, fire doors, windows, and wall assemblies, fire-resistant coatings, and other fire and smoke control assemblies. Passive fire protection systems can include active components such as fire dampers.
Fire-resistance rated wall assembly with fire door, cable tray penetration and intumescent cable coating
This I beam has a fireproofing material sprayed onto it as a form of passive fire protection.
