The LWF Blog
Fire Engineering Design and Risk Assessment – Emergency Lighting – Part 4January 12, 2017 11:42 am
In this Fire Engineering Design and Risk Assessment blog series for architects and those involved in building planning, we have most recently been exploring Emergency Lighting within buildings. In last week’s blog, we laid out the relevant documents and legislation which affect premises in the UK and discussed those areas of a building outside of the escape route which might necessitate the addition of emergency lighting.
In part 4, we will be looking at how exit signs should be illuminated and what lighting levels should be achieved for escape routes.
Exit signs highlight the route that must be taken by a building occupant to achieve a place of safety in an emergency situation such as a fire. There will be alternative routes within the building, which means that more than one final exit from the building is most likely.
Exit signs must be illuminated, this can be as part of a light fitting or a light fitting emitting light onto the sign. Details of the UK’s legal requirements for exit signs can be found in the Health and Safety (Safety Signs and Signals) Regulations 1996, correct as per December 2016. Countries outside the UK which are applying international codes should refer to NFPA 101.
While this blog series has already addressed means of escape in detail and that has included the use of wayfinding signage, the particular requirements of emergency exit signs are especially important for fire safety purposes. All emergency exit signs within a building or premises must be uniform in colour and format to ensure a lack of confusion. The siting of such signs must be clear and in references to the door indicated to avoid ambiguity and sufficient contrast must be apparent between the sign and the background.
In the UK and Europe, signs which just show text are no longer to be installed, although these remain acceptable for those countries following international codes. A combined graphical and text sign ensures that no matter the language of the reader, they should be able to understand the sign meaning and act accordingly, such signs comply with the requirements of BS 5488: 1 and may still be used if they are to be installed in a building which already has this type of sign. In some circumstances, self-luminous signs may be in use, as long as they comply with the necessary legislation.
In terms of lighting levels of emergency lighting, a minimum level of 0.2 lux on the centre line of the escape route is required in the UK as a minimum. However, it can be difficult to maintain that level over the longer term and so it is recommended that the preferred level of 1 lux along the centre line is achieved in all situations.
Because of the nature of open plan offices and the confusion that may arise due to large open spaces with excesses of furniture to pass to reach a defined exit, it is necessary to provide emergency escape lighting to the minimum level of 0.5 lux in the core area. While that is the minimum required, all safety decisions on lighting levels, provision etc. should be made as a result of an appropriately carried out risk assessment which should indicate the levels required.
In next week’s blog we will begin looking at the new subject of Fire and Smoke Ventilation. 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 for over 25 years to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact Peter Gyere on 020 8668 8663.