Fire Door Seals / Fire Smoke Seals

Fire Doors — Specification Of Timber Fire DoorsIdentifying Fire DoorsNominal Fire Doors Fire Door Seals / Fire Smoke Seals Fire Resisting Glazing Maintenance Of Fire Doors

Intumescent fire door seals with or without cold smoke seals should be fitted to the back edge, stile and head of the fire resisting door sets. The following is information on the type or size of intumescent fire door seal that should be used.

Not all intumescent materials act in the same way. Low pressure seals expand in all directions but provide little help to the door in resisting distortion under fire. Some high pressure seals exert pressure mainly in one direction and provide some resistance to distortion of the door leaf under fire. A further type of intumescent material, available in different grades, acts in all directions and generates some pressure. Fire door seals activate at temperatures that are above human survival levels.


Type of fire door Intumescent Seals Intumescent Fire and Smoke Seals
30/30 Single action door30/30 Double action door 10mm x 4mm(Both sides and top) 10mm x 4mm(Both sides and top)
30/30 Double pairs of doors 10mm x 4mm on one centre stile10mm x 4mm on other stile, heads and back edges
60/60 Single action door60/60 Double action door 20mm x 4mm(Both sides and top) 20mm x 4mm(Both sides and top)
60/60 Double pair of doors 20mm x 4mm on one centre stile20mm x 4mm on other stile, heads and back edges


In most circumstances, retention or control of smoke is required, where this is so, fire door sets must be fitted with appropriate smoke seals. These prevent the leakage of air and therefore smoke through the most vulnerable places i.e. gaps between door and frame, glazed openings and where appropriate, letter plates. Installations fitted with such seals are designated by the suffix ā€˜sā€™ after the Integrity rating i.e. FD 30s.

To achieve this, such classifications are given tests on the seals in accordance with BS 476 Part 31.1 or Certifire approved smoke seals to TS21.


Most modern fire door seals contain the intumescent and the cold smoke brush all in one fire door seal.

Grooves should be made slightly wider than the seals to allow of pre-painting and shrinkage of timber.

All hinges, locks and door closers should be fitted with intumescent material fitted between the fire door and the hardware.

Please refer to fixing and installation instructions.

Note: ā€“ It is always best to ask fire door manufacturers what type of seal to use.

Fore more detailed information go to Intumescent Fire Seals Association


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