BS 5266-1:2025 — What's Changed and What It Means for You

BS 5266-1:2025 — What's Changed and What It Means for You

Published in October 2025, BS 5266-1:2025 is now the industry reference for emergency lighting as we move through 2026. It replaces the 2016 edition in its entirety — and this isn't a light-touch refresh. BSI notes that the 2025 edition does more than update the guidance: it expands the scope of the standard to reflect advances in technology and supports a more complete approach to safety in modern buildings.

If you design, install, or maintain emergency lighting in non-domestic premises, this affects your work. Let's break it down.

Why the Update Was Needed

Buildings have changed. Multi-use spaces, progressive evacuation strategies, and the wider range of occupants needing support during an emergency mean that lighting now has to do more than simply show an exit route.

The 2016 standard was primarily focused on getting people out of buildings. That remains critical — but it's no longer the whole picture. This revision broadens the definition of emergency lighting beyond escape routes, placing greater emphasis on local area lighting and standby lighting where people may be expected to remain safely for longer periods. In a modern high-rise with a stay-put strategy, or a hospital ward that can't be evacuated in two minutes, that distinction matters enormously.

Another key driver for the revision was the need to align with updated European standards, EN 1838:2024 and EN 50172:2024. The industry benefits when product performance, photometric verification and ongoing testing are consistent across manufacturers and markets. BS 5266-1:2025 brings UK practice into line with those shared benchmarks. All three updates together — BS 5266-1:2025, BS EN 1838:2024, and BS EN 50172:2024 — aim to enhance safety and compliance, and provide clearer, more consistent guidance for the design, installation, and maintenance of emergency lighting systems in public and commercial buildings.

Three Types of Emergency Lighting — Formally Defined

The new edition expands its scope beyond emergency escape lighting to include three formally recognised categories:

• emergency escape lighting — illumination to guide people safely to an exit during an emergency;
• local area lighting — lighting specific tasks or points to enable safe completion of vital activities during power failure;
• and standby lighting — illumination that allows normal activities to continue when the main supply is lost.

This matters practically. A generator control room, a surgical suite, or a server room may all need standby lighting for operational continuity — not just escape. Designing a system that addresses only the escape route is no longer sufficient if the building's risk profile demands more.

Lux Levels and Performance Requirements

Key design values are now clearly stated. Escape routes require a minimum of 1 lux across the full route width, excluding borders. Open areas need at least 0.5 lux at floor level. High-risk task areas require a minimum of 15 lux or 10% of normal lighting, whichever is higher, with full illumination achieved within 0.5 seconds. Points of emphasis — including fire alarm call points, exit doors, firefighting equipment, and first aid posts — require a minimum of 5 lux vertical illumination.

One particularly important clarification: the standard explicitly states that borrowed light cannot be relied upon to meet emergency lighting requirements. If you've been relying on light spill from adjacent areas or exterior sources to supplement your emergency lighting design, that approach no longer holds water under the new standard.

The new lux level requirements now apply to the entire width of defined escape routes, not just the centreline. That's a meaningful change for anyone who has been verifying compliance by testing only the centre of a corridor. The whole route width must meet the standard — edge to edge.

Circuit Integrity in High-Risk Areas

This is one of the most operationally significant changes for installers. BS 5266-1:2025 introduces measures requiring emergency luminaires in high-risk areas to be wired from at least two separate circuits, with no more than 20 luminaires affected by a single circuit fault.

In plain terms: a single wiring failure must not take out a large portion of the emergency lighting in a critical area. This may require reviewing how circuits are arranged and, in some cases, introducing separate circuits to maintain adequate coverage.

This has direct implications for existing installations. If you're carrying out an inspection or EICR on a commercial premises and the emergency lighting is wired as a single circuit throughout a high-risk area, that's now something you need to flag. It's also something to build into any new design from day one — retrofitting circuit segregation is considerably more disruptive than getting it right first time.

Five-Year Photometric Verification

This is new — and it's going to catch a lot of people out. BS 5266-1:2025 introduces a strengthened requirement that every five years, premises undergo photometric testing, light level measurements and verification against the original design. This confirms that ageing fittings, layout changes or obstructions have not reduced effectiveness.

Think about how many commercial premises you've visited where the original emergency lighting design was done a decade ago, and nobody has checked whether the lux levels still comply. Layout changes, repainting of walls, new partitioning, LED retrofits — all of these can affect photometric performance. The new five-year verification requirement makes that check a formal obligation rather than an optional good practice.

For many businesses, this is now a key audit and insurance requirement. That's a commercial lever worth mentioning to clients — this isn't just about compliance for its own sake.

Testing, Documentation and Shutdown Procedures

The monthly functional test and annual full-duration test remain unchanged in principle. But the standard tightens up significantly around how those tests are recorded and managed.

The 2025 revision places greater emphasis on recording results clearly, staggering tests to avoid periods without protection, and ensuring handover information is complete and accessible.

New recommendations also include the requirement for emergency lighting systems to be protected from deep discharge during prolonged shutdowns, with clear procedures for safe recommissioning. Anyone who has left a building vacant for several months — a common scenario post-Covid, or during a fit-out — and then recommissioned the emergency lighting without a structured process needs to be aware of this.

Records must be kept on site and available for inspection. Missing or incomplete records are commonly treated as non-compliance — documentation is as important as the testing itself. Incomplete paperwork is consistently one of the most common findings during fire authority inspections. The new standard makes that even less of a grey area.

What About Automatic Test Systems?

The standard places greater emphasis on automatic test systems, and with good reason. Given the documentation burden now placed on responsible persons, automatic test and monitoring systems are no longer just a nice-to-have — they're a practical solution to a real compliance challenge. If you're specifying or recommending emergency lighting systems, this is worth having a conversation with your clients about.

What This Means for You

Whether you're a contractor, an EICR inspector, or a responsible person for a building, here's the practical upshot:

For new designs: Build in circuit segregation for high-risk areas from the outset. Size your system for the full route width, not just the centreline. Specify luminaires that support automatic testing where the building warrants it.

For existing installations: Any inspection or maintenance visit is now an opportunity to flag compliance gaps against the 2025 standard — particularly circuit integrity in high-risk areas, borrowed light reliance, and documentation quality.

For all non-domestic premises: Get the five-year photometric verification cycle in your diary now. Don't wait until an enforcement notice or an insurance claim brings it into focus.

For documentation: If your logbook isn't in good order, fix that before anything else. It's the first thing a fire authority will ask for.

Final Thoughts

BS 5266-1:2025 is a genuinely substantial update — not a box-ticking exercise. The expanded scope, the circuit integrity requirements, the photometric verification cycle, and the tightened documentation expectations all reflect real-world problems that the industry has been grappling with for years.

The buildings we're working in today are more complex, more mixed-use, and more dependent on life-safety systems than they were when the 2016 standard was written. It's right that the standard has caught up.

The question now is whether the industry responds with the same level of seriousness. Get familiar with the new requirements. Update your designs, your inspection processes, and your client conversations accordingly.

Because when the lights go out in an emergency, the gap between a system that was installed in good faith and one that was properly designed to the current standard isn't academic. It's life-safety.