Fire collars help to prevent the spread of fire where plastic ductwork penetrate fire compartment floors.
They consist of a continuous pressed stainless steel flexible shell containing high performance graphite based intumescent material which reacts under the influence of heat to exert pressure on the duct as it softens to form a carbonaceous char which provides an effective insulation plug thus preventing fire passing through to the adjoining compartment.
They should be used where a plastic duct penetrates a fire rated floor. For vertical ductwork, one unit should be installed to the underside of the floor.