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
Escape route illuminance
Escape route illuminance requirements are set out in BS EN 1838 and should be checked against the current edition.
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 design needs to establish how the route through it is lit.
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):
Circuit design should limit the number of luminaires affected by a single 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:
Photometric verification
BS 5266-1:2025 places more emphasis on photometric verification 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.
Duration should be confirmed against the fire risk assessment and the current standard.
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 | Stronger circuit resilience criteria |
| Verification | Functional tests & basic checks | Photometric verification |
| Documentation | Advisory | Stronger formal documentation and handover expectations |
| Duration guidance | Implicit | Clear duration requirements tied to risk/use |