Design now has to explicitly cover more scenarios
Plans produced during consultation and design stages must include escape route signs and special locations for emergency lighting, not just the lighting itself.
Risk assessment integration
Design must integrate results of risk assessment more directly, including when local area and standby lighting are required as part of the lighting strategy. This formalises considerations that were previously more implicit.
2. Illumination and Coverage Criteria Have Been Clarified
Whole-route illuminance requirements
Minimum 1 lx is now required across the full width of escape routes (excluding defined borders) rather than only along the centre line — ensuring more uniform and reliable visibility for evacuees.
Open areas and escape lighting through non-linear spaces
If an escape route passes through an open area that isn’t defined by a clear path, the whole open area is treated as an escape route for design purposes — potentially increasing lighting requirements in some spaces.
Specific illuminance for critical points
Design now highlights vertical illuminance requirements at fire alarm call points, firefighting equipment and other safety controls (e.g., ≥5 lx vertical), supporting safe interaction with safety systems.
High-risk tasks
Where emergency lighting must support specific local tasks in a failure (e.g., shutdown or control activities), designers must now target higher illuminance levels (e.g., ≥15 lx or 10 % of normal lighting as a minimum) with a quick response time (≤0.5 s).
3. System Integrity and Circuit Design Rules
BS 5266-1:2025 has expanded electrical design requirements (affecting how luminaires and circuits are arranged):
No more than 20 luminaires may be affected by a single central circuit fault — this increases resilience by limiting the impact of one failure.
High-risk task areas must be served by at least two separate circuits, so a single circuit fault doesn’t leave critical areas in darkness.
Cable routing and fire resistance expectations (e.g., minimum fire-resistance ratings for cables supplying emergency lights) are now explicitly part of design guidance.
These design requirements push emergency lighting away from simple luminaire placement toward system reliability engineering, which was less prescriptive in the 2016 edition.
4. Photometric Verification and Performance Assurance
One of the big practical changes affecting design documentation and validation is:
Five-Year Photometric Verification
BS 5266-1:2025 requires actual measured photometric verification every five years to confirm that installed emergency lighting continues to meet the original design criteria and illuminance predictions, not just that light fittings function.
This means designers should produce lighting designs that can be demonstrably measured — making predicted performance tangible over the life of the installation.
5. Duration Requirements More Clearly Linked to Function
The 2025 edition gives more explicit guidance on required emergency lighting duration based on building use and occupant strategy:
3-hour minimum duration is now clearly linked to buildings with sleeping occupants, phased evacuation needs, or where re-occupation is likely before batteries recharge.
1-hour minimum duration remains acceptable only where immediate evacuation is assured, clarifying long-standing ambiguity in duration design.
6. Design Documentation and Competence Expectations
The 2025 standard places greater focus on design documentation:
Design intent, verification results, test regimes and handover records are now explicitly emphasised — meaning designers must prepare documentation that clearly demonstrates how the design meets BS 5266-1:2025 criteria.
There’s also stronger reinforcement that design should be carried out by a competent person or organisation, reflecting real-world expectations around professional practice.
Summary of Key Design-Related Changes
| Design Aspect | BS 5266-1:2016 | BS 5266-1:2025 |
|---|---|---|
| Escape route illuminance | Centre-line focus | Full width coverage (with defined border) |
| Open area lighting | >60 m² anti-panic only | Smaller spaces via risk assessment; escape route continuity |
| Circuit resilience | Less prescriptive | Max 20 luminaires per fault; dual circuits for high-risk areas |
| Verification | Functional tests & basic checks | 5-year photometric verification required |
| Documentation | Advisory | Stronger formal documentation and handover expectations |
| Duration guidance | Implicit | Clear duration requirements tied to risk/use |