Emergency lighting requirements: BS 5266-1 in plain English

Central battery vs self-contained systems

Self-contained luminaires each have their own battery and are simple to install and replace individually, but batteries age at different rates and need checking unit by unit. Central battery systems (a single battery bank feeding multiple luminaires) are common in larger buildings, simplify battery replacement and monitoring, but a fault at the central battery can affect the whole system, and cable runs to luminaires must themselves be fire-rated to maintain function during a fire. Neither approach is inherently more compliant; the choice is a design decision that should suit the building's risk and management capability, and should be documented in the emergency lighting design certificate issued when the system was installed or altered.

Common defects found on inspection

The pattern of failures we see on site is consistent across building types, and almost all of it is preventable with routine testing rather than expensive remedial work.

• Luminaires with dead or swollen batteries that pass a brief functional flick-test but fail within minutes of a genuine duration test.
• Emergency lighting obscured or blocked by later works — new partitions, signage, ductwork or storage placed in front of a luminaire.
• Missing or non-illuminated fire exit signage at points where the escape route is not obvious, particularly in refurbished buildings with altered layouts.
• No test records at all, or records that show only 'passed' with no evidence a genuine duration test was ever carried out.
• Emergency lighting present in communal areas but entirely absent from external escape routes such as rear yards, external stairs or fire escape balconies.
• Charging indicator LEDs not visible or not checked, meaning a flat battery might not be noticed until the unit is actually needed.

Design changes and refurbishment

Any layout change — a new partition, a repositioned reception desk, an extended corridor, a subdivided flat — has the potential to invalidate the original emergency lighting design without anyone realising, because the design was calculated against a specific route geometry and spacing, not a general 'some lighting is present' standard. Whenever a building undergoes internal alteration, the emergency lighting layout should be reassessed by a competent designer against the new geometry, and a revised design certificate issued, rather than assuming the existing luminaires still provide adequate coverage for the changed route.

Emergency lighting in individual flats

Emergency lighting requirements generally apply to common escape routes and non-domestic premises rather than the inside of individual dwellings, which rely on ordinary room lighting and, in daytime, natural light. This is worth stating clearly to residents who sometimes assume their own flat should have a dedicated emergency light fitting; the relevant protection for the flat interior comes from the smoke and heat detection system (see our guide to fire alarm categories) rather than from emergency lighting, which is focused on the communal means of escape once someone leaves their front door.

Cost of installing and maintaining emergency lighting

For a small block, a straightforward emergency lighting installation covering communal escape routes typically sits within the same general range as other core communal fire safety works, while ongoing testing and certification is a modest recurring cost once the system is in place and being tested correctly month to month. The real cost risk is neglect: a system that has never had a genuine duration test can fail wholesale when it is finally tested properly or, worse, when it is actually needed, turning what should have been a straightforward battery replacement programme into an urgent, disruptive, and more expensive remedial project.

Emergency lighting and evacuation strategy

The emergency lighting design should reflect the building's evacuation strategy just as much as its layout does, because a stay-put building and a simultaneous evacuation building place different demands on the escape route lighting. In a stay-put block, communal escape route lighting mainly needs to support the small number of residents from an affected flat, plus firefighters working their way up the stairway, so coverage tends to concentrate on the stairs, lobbies and final exits. In a simultaneous evacuation building, every resident may be using the stairway and exits at once, which makes consistent illumination along the entire route, not just at the obvious pinch points, considerably more important, since a single dim or failed section could bottleneck a much larger flow of people trying to leave together.

Signage and wayfinding alongside lighting

Emergency lighting and fire exit signage work as a pair, and one without the other leaves a real gap: a well-lit corridor with no legible signage still leaves an unfamiliar visitor unsure which way to go, while clear signage in the dark is simply invisible. Signage should be internally or externally illuminated to remain visible when normal lighting fails, positioned at every point of doubt along the route including changes of direction and floor-level signage close to the ground for situations where smoke has banked down at head height, and checked as part of the same monthly and annual test regime as the luminaires themselves.

• Illuminated or photoluminescent signage at every change of direction and at each final exit, not only at obvious doors.
• Low-level, close-to-floor signage on key escape routes where smoke logging at head height is a realistic risk.
• Signage kept clear of later additions such as noticeboards, artwork or storage that can obscure it over time.
• Consistent pictograms and running man symbols throughout the building, avoiding a mix of styles that can confuse an unfamiliar visitor under stress.
• Signage and luminaire checks combined into the same monthly test round so neither is quietly forgotten.