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Health and Safety Services


It is a legal requirement that where members of the public e.g. visitors and students are present, final exit doors must be simple to operate.  You will be familiar with mechanical ‘push bar’ devices but electromagnetic door locks with access controls are increasingly being installed in buildings these days – including at Birkbeck and its partner institutions. These can have a variety of mechanisms for authorised persons to open the door in normal circumstances – swipe card reader, standard looking key, green 'mushroom button, rocker switch, etc.


The important points to note are: (i) An electromagnetic door lock on a fire exit route must be wired into the fire alarm system such that the power to the lock is cut when the alarm sounds so that the door can be pushed open freely.

(ii) In case the power to the door lock does not cut off when the alarm activates, and this can happen, all such doors must have an emergency door release device fitted beside them.

You can see on the above pics that the card reader and green mushroom button both  have a 'green box' beside them. This is the emergency door release.   If you find that one of these types of door lock will not open during a fire alarm - simply look for the 'green box', press the glass to crack it and the door will then push open easily.

However, these 'green boxes' are fairly inconspicuous and the writing on them is so small that many people will never have taken note of one before.  Therefore, at Birkbeck, we supplement our ‘green boxes’ with signage to draw attention to them (see below) but this may not be the case in other buildings you may visit for work or leisure.

Where security is important, the ‘green box’  will be fitted with an alarmed cover (see above) or the door itself will be alarmed to attract attention in case someone uses the emergency release in a non emergency situation. 

In buildings such as art galleries and museums with very valuable collections to protect, as well as alarmed doors and CCTV there is usually a 30 second delay on the emergency exits to allow security guards to get to them before anyone can walk out with an exhibit - just so you know in case you should ever get into that situation - a fire alarm in a top gallery or museum that is.

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Health & Safety Services, Birkbeck, University of London, Malet Street, London WC1E 7HX. Tel: 020 7631 6218, email: