The performance of timber doors is judged by subjecting them to the standard test procedure specified in BS 476 : Part 22: 1987 or BS EN 1634-1: 2000. Tests are made on complete door assemblies, the fire door and frame with all the necessary hardware. It is then fixed in a wall representing its use in practice. By testing a door in one type of frame and using it in another, no guarantee can be given of its behaviour under fire conditions. The test procedure is fully described in the Standard and consists of exposing one face of the door to heat condition expected in a fire whilst observing the door for stability and integrity. The Standard requires the tests to be carried out with the upper part of the door under a small positive pressure, to simulate the conditions likely to occur in a fire. It also provides an objective method of establishing the loss of integrity of a fire door by the use of a combustible fibrous pad on the un-exposed side of the door and see when it ignites. A fire door should be tested from each side to establish its performance with either face exposed to fire conditions, consequently requires two specimens.It is reasonable assumed all fire doors and frames manufactured to the same specification as the two specimen doors and frames will achieve the same fire resisting properties. A technique has been developed for minimising the susceptibility of door edges to early penetration by fire. It consists of applying intumescent seals to the edges so that a rise in temperature will cause the material to swell and close the gaps. Intumescent paints have been used but the most successful and reliable technique is the intumescent seal, about 4mm thick by 10 mm wide, cut into a groove in the door or the frame edge or in some cases surface mounted. As soon as the temperature in the vicinity of the strips exceeds 200°C, usually about 10-15 minutes after the start of a fire, the seal swells and seals the gaps. One fire door seal is adequate for a half hour fire door and for the increased protection needed with one-hour doors, two of these seals will be necessary. The intumescent material is soft and cellular in structure and will not prevent deformation of the door. There are fire doors that are able to resist the passage of fire for more than 30/60 minutes but these are more likely to be used for the protection of property than for means of escape from fire.
|Fire resisting doors – Door type for means of escape purposes||Integrity
 Integrity Failure is deemed to occur when
cracks or other openings exist through which flames or hot gases can pass
or when flaming occurs on the unexposed face.
 Stability Failure is deemed to occur when
collapse of the specimen takes place.