BS 5266 Emergency Lighting Essentials
Many fire alarm engineers also look after emergency lighting, and the two sit naturally together as life-safety systems. Emergency lighting does a simple but vital job: when the normal power fails, it keeps escape routes lit so people can get out safely. This guide explains what emergency lighting covers, the idea of rated duration, and the testing regime — with the specific figures left, as always, to the current standard and the building's design.
Emergency lighting is often neglected until an inspection or an incident exposes gaps, so understanding the essentials helps you keep it compliant and reliable.
Who this is for
This is for competent engineers who install, test or maintain emergency lighting alongside fire detection work. The experience level assumed is competent engineer. Use it for the essentials; use the current BS 5266 and the design documents for coverage, duration and testing specifics.
What emergency lighting covers
Emergency lighting is illumination that operates automatically when the normal supply fails. It breaks down into a few purposes: lighting escape routes so people can find and follow the way out; open-area (anti-panic) lighting to reduce panic in larger spaces and help occupants reach an escape route; and high-risk task-area lighting where a sudden loss of light during a hazardous process could be dangerous. Exit signage forms part of the picture, keeping exits identifiable.
Escape route and open area lighting
Escape route lighting illuminates corridors, stairs, changes of level, direction changes, and the locations of fire safety equipment and call points, so the route out remains usable in the dark. Open-area lighting covers larger spaces where occupants need enough light to move toward an exit without panic. The layout that achieves this — where luminaires go and how much light they provide — is a design matter set by BS 5266 and applied to the specific building.
Rated duration
Every emergency luminaire has a rated duration: the length of time it must keep providing adequate light after the normal supply fails. The duration required depends on the premises and how long escape and any subsequent activities realistically take. BS 5266 sets out what is appropriate; this article deliberately does not state a figure, because the correct rated duration comes from the current standard and the design for the building.
Maintained vs non-maintained
A maintained luminaire is lit during normal occupation as well as on failure — appropriate where a sign or light must always be visible. A non-maintained luminaire only comes on when the supply fails. Systems may be self-contained, with a battery in each luminaire, or central-battery, with a common supply. Which arrangement and type suits a given area is a design decision.
The testing regime
BS 5266 sets a routine testing regime so faults are found before they matter. In broad terms this includes brief function tests at regular intervals to confirm luminaires operate, and a full-duration test periodically to confirm they last their rated time, with all results recorded in a log book. Automatic test systems can perform and log these tests. The specific intervals and methods come from the current standard — follow them rather than a remembered routine. Common issues found on test include failed batteries, luminaires that no longer reach their rated duration, and lamps or signs obscured by later building changes.
When not to rely on this alone
When not to use this article: do not use it to set illuminance levels, rated durations, coverage or test intervals. Those come from the current BS 5266 and the emergency lighting design for the building. The standard's figures and test regime carry specific values that change between editions.
Relevant standards
Emergency lighting in the UK is designed, installed and maintained to BS 5266, a code of practice giving recommendations. The legal duty to provide emergency routes and lighting where necessary in most non-domestic premises sits under the Regulatory Reform (Fire Safety) Order 2005, and Building Regulations statutory guidance in Approved Document B applies to building work. Separate the legal duty from the recommended method when advising a client, and always work to the current editions.
Professional disclaimer
This is an educational and workflow resource for competent engineers and does not replace the current British Standards, the emergency lighting design, manufacturer data, or competent design judgement. Verify coverage, duration and testing against current documentation.
Related documentation
Use this with the current BS 5266, the emergency lighting design and log book, and the luminaire manufacturer's data. Record all function and duration tests in the log book and flag any luminaire that fails to reach its rated duration.