In the UK, doors are often tested with the minimum of building hardware fitted:
– three hinges
– a door closer
– a lock or latch
These items are known as “essential” door hardware items. These items must be carefully selected to ensure that they will perform their role satisfactorily. Most other items of building hardware on the door perform a function not directly associated with its fire performance (“non-essential”), but they must in no way impede or reduce the door’s ability to withstand fire attack for the specified time.
Under both BS 476:22 and BS EN 1634-1 test regimes, a door withstands fire attack for a period of time, for example 36 or 67 minutes, and for the purposes of regulations is then described as FD30, FD60 etc. (BS 476:22) Withstanding fire attack means not allowing flame or hot gasses to pass.
Except where otherwise noted the recommendations apply both to hinges for fire-resisting door assemblies and to those fitted to doors on escape routes. The chosen hinge must be UKCA 1121 marked to BS EN 1935, including its Annex B. When used on fire-resisting doors the product must have demonstrated its ability to be suitable for intended purpose, by inclusion in satisfactory fire test to BS EN 1634-1 or BS EN 1634-2, on a type of door assembly and configuration in which it is proposed to be used.
For timber doors and frames, fixing screws should be not less than size No. 8 (3.8mm) and not less than 30mm in length. Hinges for use on final exit escape doors should have a corrosion resistance of not less than Grade 3 of BS EN 1670. The melting point of hinges should be at 800 °c.
The torque between the two hinge leaves is important. Limits of this torque are set down in BS EN 1935; the low torque requirement of the hinge is necessary to allow the door closing device to overcome the resistance of the latch bolt and/or seal pressure. The requirements range between 2 Nm and 4 Nm dependent on the grade of hinge from 7 to 14. Hinges fitted on fire-resisting doors that are on accessible routes should have the lowest possible torque.
It is usual for at least 3 hinges to be fitted on fire and escape route doors. It is unsafe to alter the ‘as tested’ position of a hinge on a fire door, without assessment from a suitably qualified authority. For doors heavier than 160kg or exceeding 200mm in height and 1000mm in width a recommendation from the hinge/door manufacturer should be obtained. Annex D of BS EN 1935 also helps with this.
DOOR CLOSING DEVICES
Door closing devices fitted on fire-resisting doors must be able to close the leaf reliably from any angle to which it has been opened and overcome the resistance of a latch or any seals when fitted. The door closer must be UKCA 1121 Marked to BS EN 1154. The product must have demonstrated their suitability for the intended purpose, by inclusion in satisfactory fire tests to BS EN 1634-1 or BS EN 1634-2, on a type of door and configuration in which will be used. Overhead closers should have a melting point higher than 800 °c.
Concealed overhead closers should ONLY be used with a specially designed and proven intumescent protection.
The Building Regulations 1991 Approved Document B 2000 Edition requires that all fire resisting doors (except locked cupboard doors and internal domestic doors) be fitted with an appropriate self-closing device. These must be compliant with BS EN 1154.
BS EN 1154 states that door closers of less than power size 3 are not considered suitable for fire doors due to their low closing moments, especially beyond 90°. It also permits delayed action closers to be used on fire-resisting door assemblies, but it is important that any delay set is no more than that required for its use and is not more than 25 seconds.
LOCKS & LATCHES
The purpose of a lock or latch is to ensure that the doors remains closed within the frame. In most cases, the doors are single action and the role is undertaken by a latch. In certain cases there is a need for a lock to be fitted (E.g. a cupboard door or duct door).
The lock or latch must be UKCA 1121 marked to BS EN 12209. It must have demonstrated its suitability for the intended purpose by inclusion in satisfactory fire test to BS EN 1634-1 or BS EN 1634-2, on a type of door and configuration in which it is proposed to be used. Locks and latches should have a melting point above 800 °c.
According to Approved Document B Vol. 2 2006, locked doors on escape routes should be openable by one hand operation. A regular programme of maintenance must be undertaken to ensure that the correct operational performance is maintained for the life of the building.