[
Selecting the correct door closure for a fire door is more complex than it might seem. Graham Hulland guides us through the maze of of standards and certification.
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 in 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 such a device is one “which is capable of closing the door from any angle against any latch fitted to the door”. But this requirement is often overlooked, especially when the various parties involved are looking purely at the issue from a cost only point of view. Uncontrolled door closing devices are often used because they are inexpensive. But such devices may not be capable of closing the door from any angle and certainly not over any latch fitted to the door. They generally need a large angle of opening in order to build up the dynamic force required to close a door fully, and to securely overcome any resistance from the latch or seals fitted to the door.
It would sound sensible, therefore, to remove a latch which may inhibit the device from closing fully. But due to their low static closing forces, these devices rely on the latch to keep the door closed in a fire, as the positive air pressure created could be sufficient to open an unlatched door fitted with an uncontrolled closing device.
In control
To ensure full and correct closure of the door from any angle over any latch, controlled door closing devices are the most suitable solution. These provide a static closing force and are generally designed so 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 EN 1154. Once a product has been successfully third party type tested to this standard by an accredited test house, and the manufacturer has fulfiled various factory production control requirements, the tested product may be CE marked to this standard. The use of CE marked products is recommended in Approved Document B and Approved Document M (which deals with access to buildings) to show compliance with the Building Regulations 1991 schedule 1 regulation 7, in respect of the use of ‘proper materials’. Using 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 EN 1154, it will be given a classification number which will detail some of its 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 EN 1154 also details a minimum strength for a door closer fitted to a fire door – 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 that an EN1 or EN2 door closer may experience problems in closing a door from any angle over any latch fitted to the door.
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. But a CE mark alone does not allow the use of a particular door closing device on any fire door. Although the ‘1’ in the fire category is obtained by subjecting the product to a fire test to
BS EN 1634-1, 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 four hours? The requirements for these two types of fire doors are very different, and the classification does not take into account how the door closing device is fitted to the door – for example, whether it is door mounted, a parallel arm application, a slide arm or whether it is transom mounted.
It is therefore critical that any door closing device comes with additional test evidence detailing its ‘scope of approval’. This can be detailed in additional certification such as CERTIFIRE approval, where the product’s 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.
The introduction of Approved Document M and
BS 8300 have placed further requirements on devices in order to give ease of access through a 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. So, 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 device alone will exceed the 30 newtons 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 while still providing the minimum closing force of 18Nm – so the more efficient the unit then the greater the tolerance for hinges and seals.
When selecting the correct device for compliance with ADM and BS 8300, 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 EN 3 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 EN 1154 with a maximum hinge friction of 0.4Nm.
The narrower the door width quoted by the manufacturer or supplier, the more tolerance available for the resistance provided by the hinges and seals. Manufacturers may also demonstrate their opening force claims through the use of torque curves, (see chart opposite). These will show opening and closing forces and should be carried out, preferably by an independent test house.
ADM and BS 8300 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.
On hold
Hold open devices linked into the fire alarm are recommended for circulation routes, while free swing 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 EN 1155 Electrically Powered Hold Open Devices for Swing Doors. Selecting them is exactly as for a door closing device in terms of CE marking and fire test evidence but as they provide no opening resistance, they will automatically meet the requirements of ADM and BS 8300.
In addition to integral hold open devices, the use of separate magnets can also provide compliance to ADM and BS 8300. Any such magnet will also need to be CE marked to BS EN 1155. But as these 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 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 time, which would no doubt result in an integrity failure of the door when subjected to a fire.
So in summary, whether you are 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 EN 1154 or BS EN 1155 respectively, have fire test evidence detailing its scope of approval, and carry details about its suitability for compliance with ADM and BS 8300. 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.
Graham Hulland is product marketing manager for door controls at DORMA UK. In the UK, the company is made up of five specialist divisions: door hardware; automatic doors; glass systems and fittings; door service and maintenance; and movable walls.
SAFE IN HOSPITAL
The 55,000 square metre Great Western District Hospital project, with a contract value of around GB pound 100 million, has had a large number of door closures and floor springs supplied by DORMA.
No fewer than 600 TS83 and 450 TS 73 rack and pinion door closers were installed on doors throughout the hospital. These feature a variable closing force and a ‘thinking’ backcheck, which offers variable resistance according to the speed with which the door is opened. Being non-handed and with an adjustable closing speed and latching action, both models can be fitted to virtually any door, on either the pull side or the push side. Both are also independently tested to BS EN 1154, and are CERTIFIRE approved for fire doors. TS 73 EMF door closers feature 280 times throughout the hospital. These electro-magnetic closers can hold a door open at any angle between 75 and 180 degrees. If there is a fire alarm or a power cut, the hold-open is released and the door becomes self-closing once more.
Finally, 140 of the company’s floor springs were used. These were completely concealed into the transom and provide a flush installation to complement the design of any door.
The hospital, which is positioned in parkland landscaping, is set over six floors, and was a pathfinder project for the implementation of The Natural Step, an environmental initiative to work towards sustainable development. The main design and build contractor was Carillion plc.