Tuesday 20th March 2012
Following a fire risk assessment, doors are sometimes re-designated as fire doors if the door and frame are substantial enough to be justifiably counted as a nominal fire door. The same applies to older fire doors which do not follow the latest specifications. In these cases, fire door seals are retrofitted, and to avoid having to cut a rebate in either the door or the frame, surface mounted fire door seals can be fitted. These are stuck to the frame or door with their self-adhesive backing and sometimes nailed as well to give them increased longevity.
Where a fire door rebate already exists, or the existing rebated fire door seal has been damaged, rebated intumescent fire door seals can be fitted.
We offer a range of fire door seals: fire only, or combined fire and smoke. Both variants contain intumescent material that swells if a fire breaks out to seal the gap around the fire door. Seals that cover smoke also contain a brush-type smoke seal to stop smoke travelling through the gap before the intumescent material expands. There are some applications where a gap should not have smoke seals: e.g. if the fire door has been installed on the exit of a room which has no smoke detectors on its own. In this case, the fire alarm system can only be triggered if smoke can leak out around the fire door and set off the fire alarm system in the circulation spaces, but these cases are quite rare.
Fire door seals are fitted on three sides of a fire door with the gap underneath the door not being covered, though there are products available to prevent smoke from escaping under doors if necessary.