The LWF Blog

Fire Safety Engineering for Design – Escape Lighting – Part 181

April 29, 2024 10:14 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 180, LWF talked about the illumination of exit signs. In part 181, we discuss appropriate levels of illumination for escape routes and emergency safety lighting to allow ‘stay-in-place’.

When there is a failure of the main lighting provision in a building, the usual course of action is for the building occupants to evacuate the building to a place of safety. For the evacuation to take place, illumination of the escape route and escape signage must be provided. A possible alternative to evacuation is to employ the ‘stay-in-place’ system, which also requires the installation of emergency safety lighting. Whichever route is most appropriate for a building and its occupants, it is important that emergency/secondary lighting provision is made.

In the UK, there are specific recommendations relating to the level of illumination of escape routes. Escape routes must be adequately lit, including during a main lighting failure. BS 5266-1 Emergency lighting – Code of practice for the emergency lighting of premises gives the minimum illumination level to be 1 lux at floor level, along the centre line of the escape corridor up to 2 m wide.

In the rest of the world, NFPA 101 and the International Building Code both recommend a much greater level of illumination – average 1 foot candle (11 lux), with a minimum of 0.1 foot candle (1.1 lux) at any point along the path of egress

Emergency Safety (stay-in-place) lighting

Some emergency safety systems in buildings expect the occupants to stay in place when there is a lighting failure. For this to work practically, safety lighting must be employed. BS 5266-1 first mentioned the use of safety lighting in 2016. The premise is that emergency safety lighting should be provided where occupants are expected to stay in place during a main lighting failure, to ensure their safety.

Each building in which the system is expected to run should undergo a risk assessment in order that the resulting emergency safety lighting will cover the areas deemed required, which may include areas where it would not otherwise be required if the occupants were leaving the building during the main lighting failure.

In part 182 of LWF’s series on fire engineering we will begin to talk about smoke ventilation and the potential hazards of smoke spread to occupants of enclosed spaces. 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.