Because of its low density and good insulation properties exfoliated vermiculite is used in building boards. These boards are often used as a ‘core’ in firedoors, to build fire barriers, to encase or construct ductwork and to protect steel building elements from the effects of fire.
Low pressure spray applied commercial and industrial structural steel fire protection products use exfoliated vermiculite to improve the application characteristics and to impart a high degree of fire resistance.
Exfoliated vermiculite is very efficient at retaining moisture, and in the event of a fire this turns to steam which has a cooling effect on the steel substrate and thus delays its temperature rise. Vermiculite concentrate is also used in the production of fire resistant gypsum plasterboard (drywall or wallboard).