Selecting door closers for fire doors

Fire Risk Management, February 2009 (Fire Doors) / DORMA Feature

08/01/09

Selecting door closers for fire doors
[Graham Hulland, DORMA Door Controls Product Marketing Manager]

The choice of which door closing device to use on a fire door is always a point of debate, with involved parties having differing views and interpretations of the standards and regulations involved.

If the requirements detailed within the Building Regulations (Approved Document B and Approved Document M), along with national and European standards are met, then the product chosen will prove safe in use and perform as required when put to the ultimate test – in a fire!

Approved Document B (ADB) of the building regulations requires fire doors to be self closing and therefore fitted with an Automatic Self Closing Device. The ADB definition of an Automatic Self Closing Device being: ‘A device which is capable of closing the door from any angle against any latch fitted to the door’.

This requirement is often overlooked, especially when the various parties involved are looking purely at the Door Closing Device issue from a cost only point of view. Uncontrolled door closing devices are often used because they are inexpensive, however, such devices may not be capable of closing the door from any angle and certainly not over any latch fitted to the door. Such devices generally need a large angle of opening in order to build up the dynamic force required to close a door fully and securely and overcome any resistance from the latch or seals fitted to the door.

It would sound sensible therefore to remove the latch which may inhibit the device from closing fully. However, due to their low static closing forces, these devices rely on the latch to keep the door closed when subjected to a fire. Here we have a vicious circle in that the positive air pressure created in a fire situation could be sufficient to open an unlatched door fitted with an uncontrolled closing device, and when latched, the uncontrolled closing device may not be capable of closing the door from any angle.

To ensure full and correct closure of the door from any angle over any latch, a Controlled Door Closing device is the most suitable solution. Controlled Door Closing Devices provide a static closing force and their design is generally such that the highest closing force is exerted over the last few degrees to ensure the resistance provided by any latch, or other associated door hardware, can be easily overcome.

Automatic self closing devices falling into the category of a Controlled Door Closing Device are subject to a Harmonised European Standard, namely BS EN1154, Controlled Door Closing Devices. Once a product has been successfully third party type tested to this standard by an accredited test house and the manufacturer has fulfilled various Factory Production Control requirements, then the tested product may be CE Marked to this standard. The use of CE Marked products is recommended within ADB and ADM to show compliance with the Building Regulations 1991 schedule 1 / Regulation 7, in respect of the use of ‘proper materials’. The use of a CE Marked product also demonstrates compliance with the Construction Products Regulations 1991 (CPR) where products are required to be ‘safe in use’ and ‘safe in case of fire’.

Once a product has been tested and CE Marked to BS EN1154, it will be given a classification number which will detail some of the products’ properties and confirm, through the use of a ‘1’ in the safety category and fire category, that it is safe for use on fire doors. BS EN1154 also details a minimum strength for a door closer being fitted to a fire door and that is size EN3. The standard states that ‘due to their low closing moments sizes EN1 and EN2 are considered as not suitable for use on fire and smoke doors’. This reflects the requirements in ADB in that an EN1 or EN2 door closer may experience problems in closing a door from any angle over any latch fitted to the door.

Thus we have so far determined that to comply with ADB, Building Regulations and the CPR a Controlled Door Closing Device – size EN3 or above and carrying a CE mark – is the most suitable. Unfortunately these requirements are not sufficient on their own as a CE Mark alone does not allow the use of a particular Door Closing Device on any fire door. The ‘1’ within the fire category is obtained by subjecting the product to a fire test to BS EN1634-1, however, details of this test are not shown within the classification number. The successful test may have been conducted on a latched insulated timber door for 30 minutes, but would the same product perform satisfactorily on an unlatched un-insulated metal door for 4 hours?

The requirements for these two types of fire doors are very different and this excludes how the Door Closing Device is fitted to the door, door mounted, parallel arm application, slide arm, transom mounted etc.

It is therefore critical that any door closing device has additional test evidence detailing its ‘scope of approval’. This can be detailed in additional Certification such as Certifire Approval where the products’ suitability for door types and installation variants can all be detailed ensuring that the selected product is suitable for the door type it is intended for.

With all the above requirements taken into account we now have the final requirements for a door closing device to satisfy ADB, Building Regulations and the CPR, a Controlled Door Closing Device, CE Marked to BS EN1154, Sized EN3 or above with additional fire test evidence detailing its scope of approval such as a Certifire Certificate. In addition to the regulations detailed, this requirement would also ensure compliance with the new RR(FS)O guidelines which came into force on the 1st October 2006.

The introduction of Approved Document M (ADM) and BS8300 have placed further requirements on Door Closing Devices in order to give ease of access through the doorway. ADM and BS8300 require doorsets to have an opening force of 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. Although it is the doorset as a whole which is measured here, it requires door closers to be very efficient and, in general, adjustable in power to enable the doorset to comply with these requirements.

A fire door which is subject to the requirements of ADM will have a Door Closing Device which, as detailed earlier, has a minimum closing force of 18Nm (EN3). If therefore, the door is 900mm wide the door closer will be exerting a closing force of 20 Newtons. Thus if the closer is less than 66% efficient (efficiency is expressed in terms of the closing force as a percentage of the opening force) the opening force of the Door Closing Device alone will exceed the 30 Newtons opening force stipulated in ADM and BS8300 irrespective of any resistance provided by the seals and hinges.

It is therefore critical that opening forces are kept to a minimum whilst still providing the minimum closing force of 18Nm, the more efficient the unit then the greater the tolerance for hinges and seals.

When selecting the correct Door Closing Device for ADM and BS8300 compliance it is important that the correct information is obtained from the manufacturer. Most will quote a minimum door width for compliance. However, care must be taken to ensure that the minimum width quoted is with the Door Closing Device adjusted to size EN3 or above – and what friction was exerted by the hinges during the test, as a result of which this information was obtained. Tests to determine such information are normally conducted to the requirements contained in BS EN1154 with a maximum hinge friction of 0.4Nm.

The narrower the door width quoted by the manufacturer/supplier then the more tolerance available for the resistance provided by the hinges and seals. Manufacturers should also demonstrate their opening force claims through the use of torque curves, (see fig1.) (insert TS92 Torque curve) these will show opening and closing forces which ensure the opening force of the door closer is well within both requirements of ADM/BS8300 (30N from zero – 30 degrees and 22.5N from 30 -60 degrees) throughout their opening cycle and the closing force at a minimum of EN3. These torque curves should be conducted by an Independent Test House and detailed as such.

ADM and BS8300 also encourage the use of Hold Open and Free Swing Door Closing Devices, especially on circulation routes and where the opening force of a door exceeds 30 Newtons.

Hold Open Door Closing Devices linked into the fire alarm are recommended for circulation routes, whilst Free Swing Door Closing Devices are recommended for individual room access. Door Closing Devices which contain these features still have to comply with all of the requirements detailed earlier and are covered under a separate harmonised standard, namely BS EN1155, Electrically Powered Hold Open Devices for Swing Doors. The selection therefore of a Hold Open Door Closing Device or a Free Swing Door Closing Device is exactly as a Door Closing Device in terms of CE Marking and Fire Test evidence. However, as they provide no opening resistance they will automatically meet the requirements of ADM and BS8300.

In addition to integral hold open devices the use of separate magnets can also provide compliance to ADM and BS8300. Any such magnet will also be required to be CE Marked to BS EN1155, however as they are generally surface fitted and do not perform any function during a fire situation, other than ensuring the door releases when required to do so, additional fire test evidence is not generally required. An important factor when using magnets however is that care must be taken to ensure they are fitted on the same plane as the Door Closing Device. If the Door Closing Device is fitted at the head of the fire door and the Magnet at floor level then the opposing forces will result in the fire door warping and twisting over a period of time which would no doubt result in an integrity failure of the door when subjected to a fire.

So, in summary, whether one is selecting a Standard Door Closing Device, an Electro-magnetic Hold Open Closing Device, or an Electro-magnetic Free Swing Closing Device – the unit is required to be CE Marked to BS EN1154 or BS EN1155 respectively, have fire test evidence detailing its scope of approval and detail its suitability for compliance with ADM and BS8300. If all this criteria is met then 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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