Emergency Lighting Explained: BS 5266, Maintained vs Non-Maintained, and Test Regimes

Emergency lighting is a legal requirement in virtually every commercial, industrial, and multi-occupancy residential building in the UK. Yet the rules around classification, positioning, testing, and certification are frequently misunderstood — and incorrect installations can mean failed inspections, enforcement notices, or worse, putting occupants at risk during a fire.

This guide covers the essentials: the standard that governs UK emergency lighting, the difference between maintained and non-maintained fittings, category types, photometric requirements, and the test regimes you need to follow and log.

The Governing Standard: BS 5266

Emergency lighting in the UK is governed by BS 5266-1:2016 — Code of practice for the emergency lighting of premises. This is the primary document electricians, fire engineers, and responsible persons refer to when specifying, installing, and maintaining systems.

BS 5266 is not a statutory instrument itself, but it is referenced by:

• The Regulatory Reform (Fire Safety) Order 2005 (RRO) — the main fire safety legislation for non-domestic premises in England and Wales
• Building Regulations Approved Document B — covers means of escape and emergency lighting in new builds and material alterations
• BS 7671:2018+A2:2022 (18th Edition) — Section 560 covers safety services including emergency lighting circuits
• The Housing Act 2004 / HMO regulations — requiring emergency lighting in houses in multiple occupation

The responsible person (typically the building owner or employer) is legally required to ensure emergency lighting is fit for purpose, regularly tested, and documented. Non-compliance with the RRO can result in prosecution, unlimited fines, and imprisonment.

Maintained vs Non-Maintained Emergency Lighting

This is the most common source of confusion on site. The distinction is simple but critical:

Non-Maintained Emergency Luminaires

The lamp only illuminates when the normal supply fails. Under normal conditions, the lamp is off. When mains power is lost, the integral battery takes over and powers the lamp.

Typical application: Offices, warehouses, retail units, corridors — anywhere the normal lighting is adequate for everyday use and the emergency lighting only needs to activate during a power cut or fire-related supply loss.

Maintained Emergency Luminaires

The lamp is energised from both the normal supply and the battery — it illuminates at all times, whether on mains or on battery. In maintained mode, the lamp is powered by the mains; if the supply fails, the battery automatically takes over without the lamp going out.

Typical application: Cinemas, theatres, clubs, and any venue where occupants are in darkness or where the lighting circuit may be switched off while people are still present. If the exit sign or emergency luminaire is the primary light source for that area, it must be maintained.

Combined (Dual-Mode) Luminaires

Some fittings can be switched between maintained and non-maintained operation using a selector switch or by wiring configuration. These are common where a single product needs to serve multiple scenarios during a building fit-out.

Emergency Lighting Categories

BS 5266-1 defines emergency lighting by function. The three main categories are:

1. Escape Route Lighting

Provides illumination along escape routes so occupants can safely reach a place of safety. Requirements include:

• Minimum horizontal illuminance of 1 lux along the centreline of the escape route
• Ratio of maximum to minimum illuminance must not exceed 40:1
• Duration: minimum 1 hour (3 hours for buildings with sleeping risk — see below)

2. Open Area (Anti-Panic) Lighting

Covers large open areas where people may need to find their way to an escape route. Required in areas greater than 60 m². Minimum illuminance: 0.5 lux anywhere within the area, excluding a 0.5 m border at the perimeter.

3. High-Risk Task Area Lighting

Provides a minimum of 10% of the normal task illuminance (minimum 15 lux) in areas where personnel need to complete a safety procedure before evacuating — such as a machine shutdown or process isolation. This must be achieved within 0.5 seconds of supply failure (or 0.5 seconds with pre-arcing, for certain luminaire types).

Duration Requirements

The minimum duration for emergency lighting is determined by risk:

In practice, most modern self-contained emergency luminaires offer a choice of 1-hour or 3-hour battery versions. Always specify 3-hour units for any premises with a sleeping risk, and confirm the battery capacity on the label before installation.

Self-Contained vs Central Battery Systems

Self-Contained Units

Each luminaire has its own integral battery, charger, and control gear. This is the most common approach in smaller buildings. Advantages include simple installation (no dedicated battery room, no central wiring), ease of replacement, and clear local identification of faults (usually via a test/charge indicator LED on the fitting).

Disadvantages: individual batteries age at different rates, testing is more labour-intensive, and battery replacement requires access to each fitting individually.

Central Battery Systems

A central battery bank supplies emergency power to all luminaires via dedicated wiring. The luminaires themselves are standard mains fittings — the central battery takes over the supply on mains failure. This is more common in larger buildings, hospitals, schools, and high-specification commercial builds.

Advantages: single point of battery maintenance, consistent backup duration, easier monitoring. Disadvantages: higher initial cost, complex design, dedicated battery room required, more complex wiring.

Addressable Systems

Modern addressable emergency lighting systems (compliant with BS EN 62034) allow each fitting to be individually monitored, tested, and logged from a central panel. Faults are automatically identified and time-stamped. This is increasingly specified in large or complex buildings where manual testing of hundreds of fittings is impractical.

Positioning and Spacing Requirements

BS 5266-1 gives guidance on where emergency luminaires must be provided. Key positions include:

• At each exit door and final exit door
• Near each change of direction on an escape route
• Near each intersection of corridors
• Outside and near each final exit
• Near each staircase, so that each flight receives direct light
• Near any change of floor level
• At each fire alarm call point and fire-fighting equipment position
• Near each first aid point
• Outside and near any toilet accommodation greater than 8 m² floor area
• In car parks
• In motor generator, control, and plant rooms

Spacing between luminaires along an escape route should be determined by a photometric calculation to achieve the 1 lux minimum. As a rule of thumb, standard self-contained 3 W LED emergency downlights with good optics are typically spaced at 6–8 m centres in a 2–3 m-wide corridor — but always verify with a calculation or manufacturer's photometric data.

LED Emergency Luminaires: What to Look For

The vast majority of emergency fittings installed today use LED light sources. When specifying or procuring LED emergency luminaires, key parameters to check are:

Lumen Output in Emergency Mode

Unlike normal lighting where you compare wattage, emergency luminaires must be assessed on their emergency lumen output — the lumens delivered in emergency mode (battery power), not normal mains mode. Many fittings produce significantly fewer lumens in emergency mode than in normal mode. Always check the datasheet.

Battery Type and Capacity

Modern self-contained emergency fittings typically use:

• NiCd (Nickel Cadmium) — traditional, robust, wide temperature range, but restricted under RoHS in some applications and require specialist disposal
• NiMH (Nickel Metal Hydride) — environmentally preferable to NiCd, now widely used
• LiFePO4 (Lithium Iron Phosphate) — longest service life (up to 10 years), lighter, better deep-discharge tolerance; increasingly common in premium fittings

IP and IK Rating

Emergency luminaires must be appropriate for their environment. Corridors and stairwells typically need IP20 minimum. Toilets, plant rooms, or external canopies require at least IP65. High-traffic areas or vandal-prone locations need appropriate IK impact ratings.

Self-Test Functionality

Many modern units are self-testing — the fitting automatically performs the required functional test (typically weekly) and duration test (typically annually), logging results internally via an indicator LED or display. Self-test fittings can significantly reduce maintenance cost in larger buildings.

Testing and Maintenance Regimes

BS 5266-1 and the Regulatory Reform (Fire Safety) Order both require that emergency lighting is regularly tested and the results logged. The responsible person is accountable for this — and the records must be available for inspection by the fire authority.

Daily

Visual inspection of all indicator LEDs (charge indicators) on self-contained units. Any fault indicators must be investigated immediately. This is typically carried out by the responsible person or building facilities team, not the electrician.

Monthly — Functional Test

Each self-contained unit must be switched to emergency mode (by cutting the supply or using a test key/push-button) for a sufficient period to check the luminaire lights up. This is typically a short functional test — not a full duration test. Duration must be long enough to confirm operation but short enough not to discharge the battery fully. In practice, 30 seconds to 5 minutes is typical.

Record required: Date, which units were tested, results (pass/fail), person responsible.

Annual — Full Duration Test

Each unit must be switched to emergency mode and run for its full rated duration (1 or 3 hours), confirming it achieves and maintains the required light level throughout. This is a significant event — it requires the building to be managed carefully during the test (emergency power only, occupants aware), and batteries will be fully discharged and need time to recharge.

Record required: Date, units tested, test duration, pass/fail, person who carried out the test, any remedial action taken.

Periodic Inspection and Certification

Emergency lighting systems should be inspected and certified periodically by a competent electrician. The NICEIC, ECA, and NAPIT publish guidance on certification of emergency lighting systems, and some schemes include emergency lighting certification as an add-on to EICR work.

The EIC (Electrical Installation Certificate) or a separate emergency lighting commissioning certificate should be issued when a new system is installed or significantly altered.

Wiring Requirements — BS 7671 Section 560

Emergency lighting circuits are classed as safety services under BS 7671:2018+A2:2022, Section 560. Key requirements include:

• Emergency lighting circuits must be separate from other circuits and wired so that a fault on the general lighting circuit does not simultaneously disable the emergency lighting supply
• Where wiring passes through areas of increased fire risk, fire-rated cable (typically BS 6387 CWZ-rated or equivalent) must be used to maintain circuit integrity during a fire for the rated period
• Self-contained non-maintained luminaires powered from a final circuit of the normal supply are acceptable, but the supply must be taken from the distribution board in a way that does not also supply the normal luminaires — so that a local switching fault or RCD trip cannot disable both
• Central battery systems require dedicated cabling from the battery room and careful segregation from normal wiring
• Overcurrent protection must be appropriate for the cable cross-section

A common practical approach for self-contained non-maintained fittings: wire them on a dedicated final circuit from the distribution board, not on the same circuit as the area's normal lighting. This ensures the emergency circuit is energised even when the normal lighting is switched off.

Exit Signs and Safety Signs

Emergency exit signs fall under two regimes:

1. The Safety Signs and Signals Regulations 1996 — prescribe the design of fire safety signs, including the ISO 7010 green running figure exit sign (replacing the older text "EXIT" signs)
2. BS 5266-1 and BS EN 1838 — specify photometric performance for illuminated exit signs

Maintained LED exit signs must produce a minimum luminance on the green pictogram of 2 cd/m² in normal conditions and in emergency mode. Exit sign placement must ensure the signs are visible from all approaches to the escape route, with no point along the route where a sign is not clearly visible.

Internally illuminated exit signs (the box type with the green running figure) are maintained by definition — they must always be lit. Single-sided and double-sided variants are available; specify double-sided at junctions where the sign must be visible from two directions.

Common Faults and Non-Compliances Found on Site

• No testing records — the most common finding during fire authority inspections; no logbook, no test records
• Dead batteries — self-contained units with end-of-life batteries that pass visual inspection but fail the duration test
• Wrong category — non-maintained fittings in a cinema or club where maintained are required
• Insufficient coverage — gaps in escape route coverage, particularly at staircase landings or changes of direction
• Normal and emergency circuits on the same MCB — a local trip disables the escape route lighting entirely
• Incorrect IP rating — IP20 fittings in wet plant rooms or external canopy areas
• Exit signs not visible — placed too high, obstructed by doors or partitions, or not double-sided at junctions
• No commissioning certificate — no EIC or emergency lighting commissioning record when the system was installed

Practical Tips for Electricians

• Always confirm with the responsible person whether the premises have sleeping risk — this determines 1-hour vs 3-hour battery selection
• Carry a selection of 1-hour and 3-hour self-contained LED emergency downlights and bulkheads — the most common formats on UK sites
• Use self-test fittings wherever possible in commercial premises — they reduce the client's ongoing testing burden and make your installation more maintainable
• Photograph the logbook and fittings during commissioning; it takes two minutes and protects you if there's a dispute later
• When replacing fittings, check the battery condition of all fittings in the area — if one has a dead battery, others of the same age likely will too
• Ensure the test key (if used) is kept with the building's fire safety documentation, not lost in a drawer

Summary

Emergency lighting is non-negotiable in commercial and multi-occupancy residential buildings. The key points:

• BS 5266-1:2016 is the governing standard; compliance with the RRO is a legal requirement
• Non-maintained = on only in emergency; maintained = always on (required where area may be in darkness with occupants present)
• 1-hour battery for standard premises; 3-hour for sleeping risk
• Monthly functional tests and annual full-duration tests — all logged
• Self-contained LED fittings are the most common solution; central battery systems for larger buildings
• Wire emergency circuits separately from normal lighting; use fire-rated cable where required

Getting emergency lighting right protects occupants, satisfies the fire authority, and gives building owners and the responsible person the confidence that their means of escape is reliably illuminated when it matters most.