A fire batt is a slab of robust mineral fibres coated with an intumescent mastic. They are primarily used to seal gaps and openings in walls, floors, and ceilings, acting as fire barriers. Hidden gaps can leave premises vulnerable to the fast fire spread should an incident occur. By installing fire-rated batts, the spread can be slowed down, ultimately providing more time for people to evacuate.
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During a fire incident, the intumescent coating on the fire batts undergoes a chemical reaction as the surrounding temperature rises. This reaction causes the coating to expand rapidly, increasing in volume and forming a thick, insulating char layer, providing a protective layer to the material underneath.