The LWF Blog

Fire Risk Assessment for Healthcare Premises – Electrical locking devices– Part 136

May 2, 2023 11:24 am

LWF’s blog series for healthcare professionals aims to give information on best practice of fire safety in hospitals and other healthcare premises. In part 135 of Fire Risk Assessments for Healthcare Premises, LWF talked about the provision and use of electronic locks on doors in healthcare premises. In part 136, we discuss electrical locking devices.

When considering electrical locking devices on doors, it is important to consider their effectiveness and if they are appropriate for use on fire doors. There are two main types of electrically-operated entry control devices, both of which have been developed and adapted for use on fire exit doors – electromechanical and electromagnetic.

Electromechanical devices are comprised of electromechanical lock-keeps and draw-bolts, they can be operated by people inside the premises using either a code or a smart card. An electromechanical device would not be suitable for a fire escape door unless they fulfil one of the two failsafes:

• They include a manual means of overriding the locking mechanism such as a push bar, push pad or lever handle
• They do not rely on a spring mechanism and will failsafe auto-open. They should also not be affected by pressure, in which case the criteria for electromagnetic devices should be applied.

Electromagnetic devices are comprised of an electromagnet and a simple fixed retaining plate (which has no moving parts and so are considered more reliable). They should failsafe unlock in operation. The release is controlled by the electrical current to the electromagnet being interrupted. This can be done via a switch or a break-glass point, or by linking via a relay to the fire detection and alarm system of the premises. In other words, if the fire alarm triggers, the electrical current to the electromagnetic lock is ceased and the door is openable by any building occupant.

It is possible to fit a time delay provision to the electronic door locking device. This means that operating the panic bar or other exit device will result in a delay of opening of between 5 and 60 seconds (the delay is often set at the installation or manufacturing stage).

While such devices may be used in buildings or areas where they will only be utilised by staff who will have received fire safety training and will understand how the system works, they are unsuitable for use by members of the public, as the combination of a fire alarm and the door ‘not working’ is likely to cause panic.

In Part 137 of LWF’s blog series, LWF will continue talking about time-delay electromagnetic locks on fire doors, before considering the design, installation and management of electronic exit-door control devices. In the meantime, if you have any questions about this blog, or wish to discuss your own project with one of our fire engineers, please contact us.

Lawrence Webster Forrest has been working with their clients since 1986 to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact LWF on freephone 0800 410 1130.

While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.