Emergency Lighting Testing (BS 5266)
Emergency lighting only earns its keep in the seconds after a mains failure — so BS 5266 sets out a routine of monthly function tests and an annual full-duration discharge to prove it will work when it has to.
Emergency lighting is a life-safety system: when the normal supply fails, it has to illuminate escape routes and exit signs long enough for people to get out safely. Because a battery-backed fitting can look perfectly healthy while its battery is quietly dying, the only way to trust it is to test it on a schedule.
This guide covers the two tests that matter under BS 5266 — the monthly short function test and the annual full-rated-duration discharge test — the difference between maintained and non-maintained fittings, the log book you must keep, and how remedial action fits in.
Key takeaways
- BS 5266 sets a routine of monthly function tests and an annual full-duration discharge test.
- The monthly test is brief — just long enough to confirm each luminaire strikes on battery.
- The annual test runs for the full rated duration (commonly three hours) to prove battery capacity.
- Maintained fittings are lit all the time; non-maintained fittings light only when the mains fails.
- Every test must be recorded in the emergency lighting log book, with remedials tracked to completion.
The monthly short function test
The monthly test does one thing: it proves every emergency luminaire and exit sign actually switches to its battery and produces light. You simulate a mains failure — using the test facility, a test key switch or a key-operated test point — for a short period, only long enough to confirm each fitting strikes and illuminates.
The test is deliberately short so you don’t needlessly drain the batteries, because a battery that has just been fully discharged needs time to recharge before it can protect the building again. Walk the site, confirm each fitting is lit while the supply is simulated as failed, then restore the mains and check that every fitting returns to its normal state and begins charging.
Why short matters
Discharge a battery fully and it can take up to 24 hours to recharge. If you ran a long test every month you’d leave the building under-protected far too often — hence a brief monthly check and one full test a year.
The annual full-duration discharge test
The monthly test proves the fittings come on; it does not prove they will stay on. A battery can strike a lamp and then collapse after twenty minutes — useless if evacuation takes longer. The annual test closes that gap by running the system on battery for its full rated duration, most commonly three hours.
During the test the system is left in emergency mode for the whole rated period and then checked: every luminaire that was working at the start must still be providing adequate light at the end. Any fitting that dims or fails before time is up has a battery (or lamp) at the end of its life and needs attention. As with the monthly test, restore the mains afterwards and confirm the system recharges.
Maintained versus non-maintained
A maintained emergency luminaire is illuminated all the time — in normal use and during a mains failure. It is common in places of assembly such as cinemas, theatres and function rooms, where the escape-route lighting needs to be visible even when the main lights are deliberately dimmed.
A non-maintained luminaire is off during normal operation and only lights when the supply fails. It is typical in workplaces such as offices and warehouses that are only occupied while the normal lighting is on. The distinction matters when testing: a non-maintained fitting shows no light day to day, so its lamp or battery could be dead and no one would notice — which is exactly why the scheduled tests exist.
Log book and remedial action
BS 5266 expects a log book (or equivalent record) to be kept on site. Every function test and duration test is recorded with the date, the result and the person who carried it out, along with any defects found and the action taken. The log is the evidence that the system has been maintained, and it is what an enforcing authority or insurer will ask to see.
When a test finds a failed fitting, a flat battery or a sign that won’t illuminate, that becomes a remedial item: record it, act on it promptly and re-test once the repair is done. A defect logged but never closed out is worse than no log at all, because it shows a known fault was left unaddressed.
Keep the record with the certificate
TradePlanr lets you issue the BS 5266 certificate and note the test results and any remedials on site, so the paperwork matches what you actually found on the day.
Frequently asked questions
How long is the annual emergency lighting test?
It runs for the full rated duration of the system, which for most installations is three hours. The point is to prove the batteries hold up for the whole period they are rated for, not just that the fittings switch on.
What’s the difference between maintained and non-maintained?
Maintained fittings are lit continuously, in normal use and on mains failure — common in places of assembly. Non-maintained fittings light only when the mains fails, and are typical in workplaces occupied only while the normal lighting is on.
Do I need to keep records of emergency lighting tests?
Yes. BS 5266 expects a log book recording each function and duration test, the result, who carried it out and any remedial action. It is the evidence that the system has been maintained.
