CLOSERS FOR FIRE DOORS – GETTING IT RIGHT

PBM Supplier Soapbox (June 09) / DORMA

07/05/09

CLOSERS FOR FIRE DOORS – GETTING IT RIGHT
[Graham Hulland, DORMA Door Controls Product Marketing Manager]

Specifying a closing device for a fire door should be plain sailing for any contractor or manufacturer of doorsets, but sadly it is anything but simple. The factors that should help ensure the correct specification – the relevant British and European standards – can create a situation in which satisfying the need for secure automatic closure in the event of a fire, conflicts with the requirement to ensure ease of access through the doorway.

This potential conflict can be easily avoided if the correct door closing device is selected. However the difficulty arises in identifying the correct closer from amongst the range available in the market.

The two Building Regulations that need to be considered are Part B (Fire Safety) and Part M (Access to and Use of Buildings), the requirements of which are outlined in the relevant Approved Documents B and M. Both documents recommend the use of CE-marked products, as does the Construction Products Regulations 1991 which requires products to be “safe in use” and “safe in case of fire”. The closers themselves also need to be compliant with British Standard BS EN1154, Controlled Door Closing Devices.

For use on fire doors, this standard requires that closers be of size EN3, giving a closing torque of at least 18Nm. Sizes EN1 and EN2 are not suitable “due to their low closing moments” which may be inadequate to ensure closure of the door from any angle and over any latch.

The specified device must also be fire-tested to BS EN1634-1 to confirm that it is safe for use on fire doors, carrying the classification number ‘1’ to demonstrate that it is suitable for use on fire doors. Here there lies scope for confusion, since details of the test are not shown within the classification number. Hence the successful test may have been conducted on a latched insulation timber door for 30 minutes whereas the device may be fitted to an unlatched, un-insulated steel door and required to withstand fire for up to four hours.

It is therefore critical that any door closing device is accompanied by additional test evidence showing its ‘scope of approval’. This can be provided by conducting third-party tests through a certification scheme such as Certifire.

Any closer, size EN3 or above, tested to BS EN1154, BS EN1634-1, CE-marked in compliance with the CPR and with additional scope of approval certification will perform properly on a fire door in the event of a fire. But will it satisfy the requirements of Part M of the Building Regulations?

ADM and BS8300-2009 (outlining the design of buildings for the needs of disabled people) require doorsets to have an opening force no greater than 30 Newtons between zero degrees (door closed) and 30 degrees of opening and an opening force of no greater than 22.5 Newtons between 30 degrees and 60 degrees of opening. This requires closing devices of a high level of efficiency.

The ADM requirement applies to the doorset as a whole, and hence includes not only the force applied by the door closer but also the resistance due to friction in the hinges and against door seals and the inertia of the door itself.

Since a fire door must be fitted with a closer exerting a minimum closing torque of 18Nm, the closing force on a 900 mm wide door will be 20 Newtons. And if the closer is less than 66 per cent efficient across its operating range (efficiency being the closing force expressed as a percentage of the opening force) the closer itself will exceed the 30 Newtons stipulated in ADM and BS8300.

To conform to BS EN1154, an EN3 closer must be at least 55 per cent efficient. However, many manufacturers can show that, when tested to BS EN1154, their products will deliver a level of efficiency well in excess of that – as much as 80 per cent in some cases. But BS EN1154 is not ADM and to conflate the two is to mislead. The opening force recorded for BS EN1154 is not measured over the whole range of the door’s opening arc but just between the angles of 0 deg and 4 deg. The force required to open the door completely could therefore exceed 30 Newtons at any point beyond the first 4 degrees of arc.

So what does all this mean? Firstly, it means that a door closer must be chosen carefully to suit the type and size of fire door in question. Secondly, it means that the performance of any given door closer might not be all that it at first appears and that a fire-doorset thus assembled could prove non-compliant with ADM and BS8300.

Specifiers who want to ensure that their fire doors will satisfy both the requirements of ADB and ADM, and are compliant with all the relevant industry standards, need to ask for a torque-curve, produced by an independent test house. This will show the opening and closing forces for that product through the full range of operation – not just within the first 4 deg of arc.

Only then can they be sure that the closer selected will prove safe in use and perform as required when put to the ultimate test – in a fire.

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