BS 5266 emergency lighting: design, testing and duration explained

Where emergency lighting is required

BS 5266-1 identifies the locations that must be covered:

• Every escape route, at changes of direction, stairs, and intersections of corridors
• At each final exit and outside the building near the exit
• At each fire alarm call point and each item of firefighting equipment
• In plant rooms, lift cars, toilets over 8 square metres and any windowless room
• Open areas over 60 square metres — anti-panic lighting
• Areas of high risk where a task must be safely shut down

Illuminance and duration

Escape routes up to two metres wide require a minimum of 1 lux along the centre line, with anti-panic areas requiring 0.5 lux and high-risk task areas 10% of normal illuminance or 15 lux, whichever is greater.

Duration is normally three hours for premises where occupants stay on site or where the building will not be re-occupied immediately. One hour is permitted in limited circumstances, but three hours is the practical default for almost all commercial and residential buildings in the UK.

Maintained, non-maintained and self-contained systems

Maintained luminaires are lit all the time and switch to battery on failure — required in places of assembly such as cinemas and clubs where the room may be dark in normal use. Non-maintained luminaires only illuminate when the supply fails, which suits offices and industrial premises.

Most modern installations are self-contained, each luminaire holding its own battery. Central battery systems remain common in larger buildings and simplify testing but concentrate the point of failure. Automatic self-testing luminaires remove most of the manual work and are worth specifying on any new install.

The testing regime

This is the part that must be recorded. A short function test every month: simulate a supply failure long enough to check every luminaire and exit sign illuminates, then restore and confirm the charging indicators.

Annually, a full-duration test — the rated duration, normally three hours — with every luminaire confirmed as still illuminated at the end. Batteries that fail must be replaced and retested. Record the date, the result, any failures and the remedial action in the fire logbook.

Plan the annual test for a time when the building can be left unoccupied afterwards, because the batteries will need up to 24 hours to recharge and the building is not protected in the meantime.

Common failures we find

Escape signage that points along a route that has since been altered. Luminaires removed during a refurbishment and never reinstated. Batteries five or more years old that hold charge for twenty minutes rather than three hours. Test switches installed but never operated. External exit doors with no illumination outside them.

None of these are expensive to fix. All of them appear in enforcement notices.