The UK framework for emergency lighting is set by BS EN 1838:2024 (the photometric requirements), BS EN 50172:2024 (the system and testing requirements) and BS 5266-1:2025, the UK code of practice that tells you how to apply both. This guide sets out the lux levels, uniformity and timing rules, and how a survey proves compliance.
Minimum emergency lighting lux levels at a glance
| Area / function | Minimum illuminance | Where it is measured | Other key requirements |
|---|---|---|---|
| Escape routes | 1 lux | Horizontal, on the floor, across the route width (on routes wider than 2 m the outer 0.5 m each side is excluded) | Max:min uniformity no worse than 40:1 |
| Open areas (anti-panic) | 0.5 lux | Horizontal, on the floor, excluding a 0.5 m border around the perimeter | Max:min no worse than 40:1; needed in areas over 60 m² and smaller areas with extra risk |
| High-risk task areas | 10% of normal maintained illuminance, and never less than 15 lux | On the task reference plane | Uniformity no worse than 10:1; full level within 0.5 seconds |
| Points of emphasis (first aid points, fire-fighting equipment, call points, rescue plans) | 5 lux | Vertical, on the equipment itself | Luminaire within 2 m horizontally of the item |
| Accessible toilets, and showers within toilets or changing rooms | 1 lux | Horizontal, on the floor | Toilets and changing rooms over 8 m² also need open area lighting |
These are minimum values that must still be achieved at the end of the rated duration, with batteries at the end of their life and luminaires dirty.
Escape route lighting: what changed in 2024
Under the previous BS EN 1838:2013, the 1 lux requirement applied along the centre line of routes up to 2 m wide, with a central band of at least half the route width receiving 50% of that value. The 2024 edition moves the requirement to the full usable width of the route. For routes wider than 2 m, the outer 0.5 m on each side is excluded, but everything in between must reach 1 lux. In practice, that means systems designed to the old centre-line rule can fail at the edges of a wide corridor even though nothing has deteriorated.
BS 5266-1:2025 also makes clear that borrowed light, such as street lighting coming through a window, cannot be counted towards compliance.
Uniformity on routes and open areas
The ratio of maximum to minimum illuminance along an escape route or across an open area must not exceed 40:1. A route with a 20 lux pool directly under each fitting and 0.4 lux between them fails, even though the average looks generous.
Open area (anti-panic) lighting
Open areas larger than 60 m² need at least 0.5 lux on the floor across the core area. Smaller spaces need it too where the risk assessment identifies a hazard. Where an escape route crosses an open area and is not clearly defined, the standard requires the shortest obvious path to be lit to escape route levels (1 lux) over a width of at least 2 m.
High-risk task area lighting
Where someone operates machinery or a control panel, the requirement is 10% of the normal maintained illuminance or 15 lux, whichever is greater, with uniformity no worse than 10:1. A production line normally lit to 500 lux therefore needs at least 50 lux of emergency lighting on the task. High-risk areas are common in our factory and industrial surveys.
Points of emphasis: 5 lux vertical
BS EN 1838:2024 requires a luminaire within 2 m (measured horizontally) of each first aid point, item of fire-fighting equipment, fire alarm call point, escape route and rescue plan, and refuge or other safety equipment for disabled people, so that at least 5 lux vertical illuminance falls on the item. The 2024 edition also adds lift alarm points and manual release controls for electronically locked doors. Because this is a vertical measurement, a fitting that lights the floor brilliantly can still leave a wall-mounted extinguisher well below 5 lux.
Response time and duration
- Response: escape lighting must reach 50% of its required level within 5 seconds and full level within 60 seconds. High-risk task lighting must reach full level within 0.5 seconds.
- Duration: BS 5266-1:2025 recommends a 3-hour duration for most premises, and it is the expected minimum anywhere people sleep (hotels, care homes, HMOs) or where the building may be reoccupied soon after mains power is restored. A 1-hour duration is acceptable only in limited cases where the building is evacuated immediately and not reoccupied until the batteries have recharged.
- Colour rendering: emergency lighting should have a colour rendering index of at least Ra 40 so that safety colours on signs remain recognisable.
The legal duty
Under the Regulatory Reform (Fire Safety) Order 2005, the responsible person must ensure that escape routes and exits are lit by emergency lighting of adequate intensity where it is needed, and that the system is maintained and tested. Separately, regulation 8 of the Workplace (Health, Safety and Welfare) Regulations 1992 requires suitable emergency lighting wherever workers would be especially exposed to danger if the artificial lighting failed (see our workplace regulations guide). BS 5266-1:2025 is the benchmark used to judge "adequate".
How an emergency lighting lux survey is carried out
- Darkness first. Measurements are taken with normal lighting off and daylight excluded, usually out of hours. Any remaining ambient light is measured separately and subtracted.
- Simulated mains failure. The emergency circuit is isolated (or the test switch operated) so luminaires run on battery, as they would in a real failure.
- Floor-level grid readings are taken along each route and across open areas, concentrating on the darkest points midway between fittings, at corners, changes of direction and level, and at the edges of the route.
- Vertical readings are taken at each point of emphasis, with the meter facing the direction someone would approach from.
- End-of-duration check. Where the client requires it, readings are repeated near the end of the rated duration to confirm the levels are sustained, not just the initial output.
The meter matters. At 0.5 lux, a poor general-purpose meter can turn a fail into a pass. We use a calibrated meter that resolves to 0.1 lux or better. Our guide to how lux is measured explains the method in more detail, and the lux survey report guide shows what you should receive afterwards.
Common failures we find
- Wide corridors that pass on the centre line but fail at the edges under the 2024 full-width rule.
- Points of emphasis well below 5 lux vertical, especially extinguishers in recesses.
- Ageing batteries that pass a short monthly function test but fall below 1 lux well before three hours.
Book an emergency lighting lux survey
Polarity Lux carries out measured emergency lighting surveys across London and the South East, including Hertfordshire, Essex, Kent and Surrey. Each survey reports measured lux against BS EN 1838:2024 and BS 5266-1:2025 for every route, open area and point of emphasis. An emergency escape lighting check starts from £120, and the price is confirmed before booking. See our emergency lighting service or book your survey online.
Frequently asked questions
What is the minimum lux level for emergency escape routes?
BS EN 1838:2024 requires at least 1 lux horizontal illuminance on the floor of an escape route. On routes wider than 2 m, the outer 0.5 m on each side is excluded, but the rest of the route width must reach 1 lux.
How many lux is required for anti-panic lighting?
Open area (anti-panic) lighting must provide at least 0.5 lux on the floor, excluding a 0.5 m border around the perimeter. The ratio of maximum to minimum illuminance must not exceed 40:1.
What lux level is needed for high-risk task areas?
High-risk task area lighting must provide 10% of the normal maintained illuminance or 15 lux, whichever is greater, with uniformity no worse than 10:1. It must reach full output within 0.5 seconds.
How long must emergency lighting last?
BS 5266-1:2025 recommends 3 hours for most premises, and it is the expected minimum where people sleep or the building may be reoccupied quickly. A 1-hour duration is acceptable only where the premises are evacuated immediately and not reoccupied until the batteries have recharged.
Does a monthly flick test check lux levels?
No. A monthly function test only confirms that luminaires light on battery. Only a measured survey with the normal lighting off confirms that the required lux levels are actually achieved across routes, open areas and points of emphasis.
Can daylight or street lighting count towards emergency lighting?
No. BS 5266-1:2025 makes clear that borrowed light cannot be relied on to meet emergency lighting requirements, so surveys are carried out in darkness with ambient light excluded or subtracted.