The LWF Blog

Fire Safety Engineering for Design – Emergency Lighting – Part 176

March 25, 2024 11:24 am

LWF’s Fire Safety Engineering blog series is written for Architects, building designers and others in the construction industry to highlight and promote discussion on all topics around fire engineering. In part 175, LWF began to discuss emergency lighting, particularly in relation to escape routes and essential escape from a building on fire. In part 176, we continue to discuss emergency lighting.

A loss of lighting in a sudden and unexpected manner can result in triggering other situations which may be dangerous or even life-threatening. Where this may be the case, an assessment should be carried out to measure the overall risk and appropriate actions to be taken. The assessment may include a behavioural element designed to assess how the building occupants are likely to respond to a loss of lighting and to mitigate any areas which may be considered inappropriate through measures such as management procedures.

During the design of a building and its lighting provision, discussions should take place with the building owner and any other designers to understand how occupants will be managed during a lighting failure and to take into account any unusual hazards present.

Sometimes, people assume that the emergency lighting system and fire alarm system should be linked so that if the fire alarm is triggered, the emergency lighting will automatically activate. This is suitable in some premises such as theatres and cinemas where the standard lighting is already dimmed and people need immediate full lighting to navigate their way safely on the evacuation route.

Where the emergency lighting is designed to operate only when the mains power is lost, this should occur independently of the fire alarm and only upon detection of the power outage.

The reason that the backup emergency lighting shouldn’t be used when it is not required, even in conjunction with the fire alarm in premises that do not call for it, is that the systems are usually battery operated and will require re-charging before staff are allowed to reoccupy the building. This could lead to extended downtime for the organisation, perhaps because of a false fire signal.

When the Fire Service makes the decision to isolate power within a building, the emergency lighting system should respond to that action by detecting the loss of mains power and activating the backup lighting.

In part 177 of LWF’s series on fire engineering we will discuss the siting of essential escape lighting. 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 the LWF office on 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.

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