The LWF Blog

Fire Safety for Facilities Management Personnel – Fire Detection & Fire Alarms – Part 195

April 3, 2023 11:36 am

Lawrence Webster Forrest (LWF) is a specialist fire engineering and fire risk management consultancy whose aim is to give information on best practice in fire safety for facilities management personnel through this blog series. In part 194, LWF looked at the sound pressure levels of alarm sounders. In part 195, we will continue to look at the necessary sound pressure levels required in different types of environment.

In particularly noisy areas, where auditory alarms may not be heard clearly, supplementary flashing beacons may be advisable to supplement the alarm sounders. Flashing beacons may also be used to assist people with hearing difficulties in the work environment and are also seen in TV studios where audible sounders must be isolated during live transmissions.

It is important that the flash rate of flashing beacons is limited to avoid the potential for causing seizures in persons with photo-sensitive epilepsy.

BS 5839-1 Fire detection and fire alarm systems for buildings – Code of practice for design, installation, commissioning and maintenance of systems in non-domestic premises recommends a flash rate of between 30-130 flashes per minute which is unlikely to cause any issues for most people with photo-sensitive epilepsy. However, in large open spaces where more than one beacon will be placed, it is important that the flashes are synchronised or there is a potential for a person to see more than one beacon at a time and the effect could be multiplied in un-synchronised flashing beacons.

In buildings where deaf and hard of hearing people work, a solution to ensuring they are aware of a fire alarm as it is triggered is to provide any affected person with a vibrating pager connected to the fire alarm system. This means that it doesn’t matter if they are in an open space, away from their usual working environment or in the toilet, they will still be notified promptly of the need to evacuate.

In buildings where deaf or hard of hearing people sleep, the provision of flashing beacons and vibrating pads to be inserted under pillows or mattresses is advisable to ensure it is not possible for them to sleep through a fire alarm unaware of the situation. The pads are linked to the fire alarm system and designed to rouse sleeping occupants. BS 5446-3 gives a specification for a domestic kit to be used in people’s homes, however, there is no reason why this standard would not also be suitable for a hotel, for instance.

In part 196 of this series, LWF will begin to discuss voice alarm systems. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact LWF on freephone 0800 410 1130.


Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 35 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.


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.

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