The LWF Blog

Fire Safety for Facilities Management Personnel – Emergency Escape Lighting – Part 171

October 10, 2022 11:09 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 170, LWF discussed the siting of luminaires along an escape route, as well as other places where they may be required. In part 171, we look at the level of illumination required from emergency escape lighting, along the escape route.

BS EN 1838:2013 is the standard giving guidance on emergency lighting systems in the UK.

The recommendation for illuminance at floor level on the centre line of the route should be a minimum of 1 lux.

For escape routes up to 2 metres wide, the code recommends that 50% of the width be lit to a minimum of 0.5 lux. Where the escape route is wider than 2 metres, it should be treated as a number of 2 metre wide strips.

Where the escape route encompasses an open plan area with undefined escape routes, a minimum of 0.5 lux should be achieved over the core area, not including the area 0.5 metres or less from the walls.

The recommended levels of luminance should be achieved even under the most adverse conditions. Aside from the potential for smoke obscuring vision and reducing light, there are other potential issues that can cause an undesirable lowering of lux, for example, towards the end of the designed duration when voltage reduction may be experienced, if the lamps are ageing, or where the diffusers on the luminaires are dirty.

The manufacturer’s data on illuminance levels and lamp spacing does not take into account reflections from wall surfaces etc. which can increase the overall lux in that area.

To take into account all these potential variables, it is usually the case that higher levels of illumination are provided to ensure the minimum possible level is achieved under adverse circumstances.

Higher levels of lux may also be necessary in buildings occupied by a significant number of partially-sighted people to enable them to identify and follow the escape route out to a place of safety.

In part 172 of this series, LWF will begin to look at checks on emergency escape lighting systems and how test facilities should be incorporated into the emergency escape lighting system design. 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 25 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.