UK Overhauls Emergency Lighting Standard

Background: Why the Standard Was Revised
What Has Changed in BS 5266-1:2025
Direct Impact on LED Emergency Drivers
What Building Owners and Installers Must Do Now
Industry Reaction
Sources

Background: Why the Standard Was Revised

On 29 October 2025, the British Standards Institution (BSI) published BS 5266-1:2025 Emergency Lighting — Emergency Lighting of Premises: Code of Practice. The new edition replaces BS 5266-1:2016 and constitutes a full revision, not a minor amendment. It is now the operative reference standard for any emergency lighting design, installation, or maintenance work carried out in the UK.

The revision was driven by three converging pressures. First, buildings have become more complex — mixed-use, multi-occupancy structures with progressive evacuation strategies require emergency lighting to do more than simply mark an exit route. Second, the standard needed to align with updated European benchmarks: BS EN 1838:2024 Lighting Applications — Emergency Lighting for Buildings and BS EN 50172:2024 Emergency Escape Lighting Systems, both of which were themselves revised in 2024. Third, recurring real-world failures — battery degradation, circuit faults, and incomplete testing records — exposed gaps between theoretical compliance and actual system performance.

The Building Safety Act 2022 and the Regulatory Reform (Fire Safety) Order 2005 both require premises to maintain adequate emergency lighting. BS 5266-1:2025 is the practical framework that supports compliance with those legal duties.

What Has Changed in BS 5266-1:2025

The 2025 edition introduces several technical changes with direct consequences for how emergency lighting systems are specified and built:

Expanded scope: The standard now formally covers three categories of emergency lighting — emergency escape lighting, local area lighting, and standby lighting. Previous editions were primarily focused on escape routes. This broadened scope means more areas of a building may now require dedicated emergency lighting coverage.
Full-width lux levels: Minimum illuminance of 1 lux must now be achieved across the entire width of an escape route, not just along its centreline. Open areas require at least 0.5 lux at floor level. High-risk task areas must reach 15 lux (or 10% of normal lighting, whichever is higher) within 0.5 seconds of mains failure.
Circuit resilience: No more than 20 luminaires may be affected by a single circuit fault on centrally supplied final circuits. High-risk task areas must have dual circuit supply from at least two separate circuits.
Five-year photometric verification: All three standards now require formal verification of system photometric performance every five years to confirm continued compliance with the original design specification.
Battery and shutdown protection: New requirements address deep discharge prevention during prolonged shutdowns and specify clear recommissioning procedures — directly affecting battery management in self-contained LED emergency drivers.
Documentation and handover: Handover documentation requirements are significantly more detailed, with a clearer structure for testing records and audit trails.

Direct Impact on LED Emergency Drivers

LED emergency drivers — the self-contained or centrally supplied modules that switch luminaires to battery backup when mains power fails — sit at the technical heart of every emergency lighting system covered by BS 5266-1:2025. The revised standard raises the bar in several ways that directly affect driver selection and system design:

Battery management: The new requirements around deep discharge protection and recommissioning mean that LED emergency drivers must include robust battery management circuits capable of preventing overdischarge during extended shutdowns, such as building closures or planned maintenance windows. LiFePO₄ battery chemistry, which offers greater cycle stability and discharge tolerance than older NiCd or NiMH cells, is increasingly relevant here.

Automatic testing: BS 5266-1:2025 places a stronger emphasis on automatic test systems, particularly in premises where occupants may be present during a mains failure. LED emergency drivers with built-in self-test functionality — including DALI-connected monitoring — directly support this requirement and reduce reliance on manual testing regimes that have historically produced gaps in compliance evidence.

Circuit fault tolerance: The 20-luminaire limit per circuit fault means designers can no longer rely on a small number of high-output centrally supplied circuits. This may require moving toward more distributed self-contained LED emergency drivers, each with its own backup module, to satisfy fault tolerance requirements without rewiring entire circuits.

Lumen output and photometrics: The full-width lux requirement for escape routes increases the demand on driver output accuracy. Drivers that allow programmable emergency output levels — typically expressed as a percentage of normal operating current — give designers the control needed to meet specific lux targets without over-specifying luminaire wattage.

What Building Owners and Installers Must Do Now

BS 5266-1:2025 is a code of practice, not a legally enforceable regulation in itself — but compliance with it is strong evidence of due diligence under the Building Safety Act 2022 and fire safety legislation. For existing buildings, the standard does not automatically invalidate systems installed to the 2016 edition, but it does set the benchmark against which those systems will be assessed during inspection, audit, or post-incident review.

Practical steps recommended by industry bodies include: reviewing existing circuit layouts against the new fault tolerance requirements; checking whether self-contained driver units include adequate battery protection for shutdown scenarios; confirming that testing regimes and logbooks meet the updated documentation expectations; and scheduling photometric verification where systems are approaching or beyond five years old.

For new installations and major refurbishments, specifiers should confirm that LED emergency drivers on the specification comply with the battery management, self-test, and output control requirements implied by the new standard.

Industry Reaction

The Electrotechnical Contractors’ Association (ECA) welcomed the update. Mike Smith, Technical Director at ECA, noted that the organisation and its members contributed directly to the BSI committee that developed the revisions, describing the outcome as delivering “clearer guidance, improved safety, and more robust compliance frameworks across the sector.”

Industry commentators have also noted that the alignment with EN 1838:2024 and EN 50172:2024 reduces cross-border ambiguity for manufacturers supplying LED emergency driver products across the UK and European markets, supporting more consistent product performance verification and reducing the risk of divergent compliance interpretations post-Brexit.