What is BS 5266-1?

BS 5266-1 is the British Standard that sets out how emergency lighting should be designed, installed, tested and maintained in non-domestic premises. It works alongside the Regulatory Reform (Fire Safety) Order 2005, which is the actual legislation placing a legal duty on the "responsible person" for a building to ensure escape routes are properly lit if the mains power fails. BS 5266-1 is the accepted way of demonstrating you've met that legal duty - if your system is compliant with the standard, you're considered compliant with the law.

The new edition came into effect on 31 October 2025, replacing the version that had been in place since 2016.

The change most businesses don't know about yet

The headline change is a new requirement for photometric verification every five years. This means having the actual light levels at floor level across your escape routes and open areas independently measured and checked against the original design specification, rather than simply confirming the lights switch on.

This matters because a system can pass its monthly and annual functional tests - lights illuminate, batteries hold charge for the rated duration - while still failing to deliver enough light where it's actually needed. Layout changes, new partitions, added storage, or simply ageing fittings can all reduce effective illuminance over time without it being obvious from a standard test. Photometric verification catches that gap.

For many Surrey businesses, particularly those in premises that have been refitted, extended or had layout changes since the lighting was originally designed, this is a new audit requirement worth getting ahead of rather than discovering during a fire authority inspection or insurance review.

What hasn't changed

The existing testing schedule under BS 5266-1 and BS EN 50172 remains the foundation of compliance, and most businesses already have this in place:

A monthly functional test, where the mains supply is briefly interrupted to confirm every luminaire switches to battery power correctly, with any failures logged and repaired promptly. An annual full-duration test, which discharges the system for its complete rated duration - typically three hours for most commercial premises to confirm the batteries can actually sustain emergency lighting for the period needed.

Both of these remain mandatory and unchanged. The five-year photometric verification sits alongside them as an additional requirement, not a replacement.

Who does this affect?

Emergency lighting, and therefore this update, applies to virtually all non-domestic premises in the UK where people work, shop, or otherwise have access - offices, retail units, warehouses, industrial premises, restaurants and hospitality venues among them. If your premises has emergency lighting fitted - which almost all commercial buildings do, the new standard applies to you.

What Surrey businesses should do now

If your emergency lighting system has never had a photometric verification, or you're not sure when it was last assessed against its original design, this is worth raising at your next fire risk assessment review. Three practical steps:

Check your logbook. A compliant system should have documented records of every monthly and annual test. If these are incomplete or missing, that's typically treated as non-compliance regardless of whether the lighting itself is working correctly.

Establish when your system was last verified against its original design, not just functionally tested. If it's been more than five years, or you don't know, it's worth getting this scheduled.

Confirm your current contractor is aware of the October 2025 update. Compliance work carried out under the old assumptions won't necessarily meet the new requirement.

How MS Electrical Solutions can help

MS Electrical Solutions installs, tests and certifies emergency lighting systems to BS 5266 for commercial premises across Horley, Crawley, Reigate, Redhill, and the wider Surrey and West Sussex area, including businesses operating within the Gatwick Diamond business community. We carry out monthly and annual testing, maintain proper logbook documentation, and can advise on bringing existing systems up to the current 2025 standard. Call us directly on 07508 224603 to discuss your premises.