Under EN 1838, escape route lighting for routes up to 2 m wide needs at least 1 lx on the centre line, anti-panic (open) areas need at least 0.5 lx, and high-risk task areas need at least 10 % of the normal illuminance, but never less than 15 lx. Fire-fighting equipment, manual call points and first aid points need at least 5 lx vertical. Escape route lighting must reach 50 % of the required illuminance within 5 seconds and 100 % within 60 seconds.
Which standard defines emergency lighting illuminance?
EN 1838 is the European standard that sets the photometric requirements for emergency escape lighting – illuminance, uniformity, glare limitation, colour rendering, response times and minimum duration. It applies in all CEN member countries, published nationally as, for example, DIN EN 1838 in Germany or BS EN 1838 in the UK. Design, installation and testing of systems are covered by EN 50172, supplemented by national rules such as DIN VDE V 0108-100-1 in Germany. For an overview of how these fit together, see Emergency lighting standards.
Illuminance is measured in lux (lx). One lux is the illuminance produced by a luminous flux of one lumen falling evenly on one square metre. For comparison, office workstations are typically lit to around 500 lx – emergency lighting values are deliberately low because they serve orientation, not work.
All EN 1838 minimum values at a glance
| Area | Illuminance | Uniformity | Response time | Duration |
|---|---|---|---|---|
| Escape routes up to 2 m wide | at least 1 lx horizontal at floor level on the centre line; central band (at least half the route width) at least 50 % of that | Emax : Emin no more than 40 : 1 along the centre line | 50 % within 5 s, 100 % within 60 s | at least 1 h |
| Anti-panic (open) areas | at least 0.5 lx horizontal on the empty floor area, excluding a 0.5 m border | Emax : Emin no more than 40 : 1 | 50 % within 5 s, 100 % within 60 s | at least 1 h |
| High-risk task areas | at least 10 % of the maintained illuminance required for the task, minimum 15 lx | at least 0.1 (Emin : Eaverage) | 100 % permanently or within 0.5 s | as long as the hazard exists |
| Safety equipment (fire-fighting equipment, manual call points, first aid points) | at least 5 lx vertical at the equipment | – | as escape route | as escape route |
For all areas, EN 1838 also requires a colour rendering index of at least Ra 40, so that safety colours such as green and red remain recognisable. The one-hour minimum duration is a floor: national building regulations often require longer, frequently three hours for certain building types – see Emergency lighting duration.
Escape routes: what does "1 lx on the centre line" mean?
For escape routes up to 2 m wide, the horizontal illuminance at floor level is assessed along the centre line. Every point on that line must receive at least 1 lx. In addition, a central band covering at least half the width of the route must receive at least 50 % of that value. Wider routes are either treated as several 2 m strips or as open areas.
The ratio of maximum to minimum illuminance along the centre line must not exceed 40 : 1. This prevents bright pools of light followed by dark zones the eye cannot adapt to quickly enough.
Practical tip: The values apply to the worst case – at the end of the rated duration and over the life of the installation. Calculate with realistic maintenance and ageing factors and without reflected light from walls and ceilings; EN 1838 generally considers direct light only.
Anti-panic lighting: 0.5 lx on the open floor
In larger areas without defined escape routes, a minimum horizontal illuminance of 0.5 lx applies on the empty floor area. A 0.5 m border along the walls is excluded from the calculation. Uniformity must again not exceed 40 : 1. The room size from which anti-panic lighting is needed depends on the standard, the risk assessment and national rules.
High-risk task areas: 10 %, at least 15 lx
Where a sudden loss of light creates an immediate danger, emergency lighting must provide at least 10 % of the maintained illuminance required for the task, and never less than 15 lx. Example: if machine operation requires 500 lx, at least 50 lx is needed in emergency mode. With 100 lx normal lighting, the 15 lx minimum applies instead.
Speed is critical here: the full illuminance must be available permanently or within 0.5 seconds. The duration must cover the period for which the hazard exists.
Safety equipment: 5 lx vertical
Fire extinguishers, hose reels, manual call points and first aid points must remain easy to find and use in emergency mode. Where they are not already on a lit escape route or in a lit open area, EN 1838 requires at least 5 lx vertical at the location of the equipment. In practice this usually means a luminaire within about 2 m horizontally of the equipment.
National workplace rules: the German example
Many countries add workplace rules on top of EN 1838. In Germany, the Technical Rules for Workplaces (ASR) apply: emergency escape lighting was long covered by ASR A3.4/3 "Safety lighting, optical safety guidance systems", whose content has since been incorporated into the revised ASR A3.4. The values there essentially match EN 1838 – at least 1 lx on escape routes and at least 15 lx at high-risk workplaces. Whether a workplace needs escape lighting at all follows from the risk assessment and ASR A2.3. Other countries have their own equivalents; always check the current national version.
How do you plan illuminance correctly?
A compliant installation is the result of a photometric calculation, not guesswork. A proven approach:
- Clarify layout and use: mark escape routes, open areas, high-risk task areas and safety equipment on the floor plan.
- Define mandatory positions: exits, stairs, changes of direction, intersections, safety equipment.
- Plan with LDT files: the light distribution of each luminaire is available as a EULUMDAT (LDT) file. Software such as DIALux or Relux uses it to calculate floor-level illuminance in emergency mode.
- Check spacing tables: manufacturers publish maximum spacings for 1 lx and 0.5 lx at different mounting heights for each optic.
- Document the result: the calculation belongs in the system documentation and the emergency lighting logbook.
Optics matter a great deal. A wide corridor lens (around 135 × 55°) allows larger spacings along an escape route than a rotationally symmetric optic, which is better suited to open areas.
Frequently asked questions
How many lux does an escape route need?
Under EN 1838, at least 1 lx on the centre line at floor level for routes up to 2 m wide. The central band must reach at least 50 % of that, and the ratio of maximum to minimum illuminance must not exceed 40 : 1.
How bright must anti-panic lighting be?
At least 0.5 lx horizontal on the empty floor area, ignoring a 0.5 m border along the walls. Uniformity must not exceed 40 : 1.
How quickly must emergency lighting switch on?
Escape route lighting must provide 50 % of the required illuminance within 5 seconds and 100 % within 60 seconds. In high-risk task areas the full illuminance must be present permanently or reached within 0.5 seconds.
How many lux are needed at a fire extinguisher?
At least 5 lx vertical at its location, unless the extinguisher is already on a lit escape route or in a lit open area. The same applies to manual call points and first aid points.
Can illuminance be measured on site?
Yes, with a calibrated lux meter in emergency mode and with normal lighting switched off, ideally at night or in darkened rooms. Because very low values are measured, the meter needs adequate resolution below 1 lx.
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