Emergency lighting · BS 5266-1
How much light does emergency lighting need?
The lux levels for escape routes, open areas and fire equipment, how long the light must last, and how often it is tested and measured.
The light levels
Light is measured in lux. The minimum levels for emergency lighting come from BS EN 1838, which BS 5266-1 points to:
| Where | Minimum | How it is measured |
|---|---|---|
| Escape route | 1 lux | Across the whole width of the route, less a border |
| Open area | 0.5 lux | Across the space, leaving out a 0.5 m border |
| Fire equipment, call points, door releases and rescue plans | 5 lux | Measured vertically, near the item |
The free lux checker compares a set of readings with these minimums.
Escape routes: the whole width
The 2024 edition of BS EN 1838 asks for at least 1 lux across the whole width of the escape route, apart from a border. The border is 0.5 m each side for routes over 2 m wide, and a quarter of the width each side for routes up to 2 m wide.
The 2013 edition only measured the centre line. A reading taken down the middle of a corridor may have passed under the old wording and still miss the new one, so check which edition a design was done to.
Open areas and the route through them
An open area needs at least 0.5 lux across the space, leaving out a 0.5 m border. The 2024 edition also asks for the shortest obvious route through the area to be lit as an escape route.
High-risk task areas
In the 2013 edition, high-risk task areas need the higher of 15 lux and 10% of the normal task lighting level. We have not found this figure quoted for the 2024 edition, so check the current wording before you rely on it.
How long must the light last?
It depends on how the building is used:
- 1 hour where the premises are emptied at once and not used again until the batteries have recharged
- 3 hours where people cannot leave at once, such as sleeping accommodation, or where the building is used again before the batteries recharge
Testing and measuring it again
A functional test every month, and a full-duration test every year by a competent person. Results go in the log book. BS 5266-1:2025 also asks for the light levels to be verified at commissioning and again at intervals not exceeding five years, and BS EN 50172:2024 says illuminance measurements are made once every five years.
Each section of an escape route also needs at least two light sources, so one failure does not leave it dark.
Common questions
How many lux does emergency lighting need on an escape route?
At least 1 lux across the whole width of the route, less a border of 0.5 m each side for routes over 2 m wide, or a quarter of the width each side for routes up to 2 m wide.
How much light does an open area need?
At least 0.5 lux across the space, leaving out a 0.5 m border.
How much light do fire extinguishers and call points need?
At least 5 lux, measured vertically, near fire-fighting equipment, call points, door releases, rescue plans and safety equipment for disabled people.
Should emergency lighting last 1 hour or 3 hours?
1 hour where the premises are emptied at once and not used again until the batteries have recharged. 3 hours where people cannot leave at once, such as sleeping accommodation, or where the building is used again before the batteries recharge.
This guide is general information for UK fire & security companies, not legal or engineering advice. Always work to the current edition of the relevant standard and your own competent-person judgement.
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