Emergency lighting is specified by how much light lands on the floor when the mains supply fails, and for how long it stays there. The only routine failure at audit is a missing test record. Two standards do the work: IEC 60598-2-22 for the luminaire itself, and EN 1838 for the application, meaning how much light and where.
What the Application Standard Requires
EN 1838 divides an industrial site into zones, and each zone gets its own illuminance figure measured at floor level along the path people actually walk.
| Zone | Illuminance | Notes |
|---|---|---|
| Escape route, centre line | 1 lux | Measured horizontally at floor level |
| Open anti-panic area | 0.5 lux | Larger halls and open floors |
| High-risk task area | 10% of normal task lighting, minimum 15 lux | Where a shutdown would endanger the operator |
| Exit sign | Specified by luminance, commonly 2 cd/m2 or above | Must stay legible, not just lit |
Duration matters as much as level. One hour is the common baseline for escape route lighting where the building is evacuated immediately. Longer durations, typically 1.5 or 3 hours, are called for where occupants cannot leave at once or where the site must stay occupied during an outage. A plant with a night shift and no immediate evacuation route should be checked against the longer figure.
Self-Contained or Central Battery
A self-contained luminaire carries its own battery, charger and changeover circuit. A central battery system feeds all emergency fittings from one room. Self-contained units are easier to extend and fail one at a time. Central systems concentrate maintenance and monitoring in one place, which suits a large plant with many fittings on one floor plan, but a single fault takes out a whole zone.
Battery chemistry decides the temperature window. Nickel-cadmium tolerates heat and cold better than lithium chemistries but is heavier. Lithium iron phosphate packs hold capacity well in unheated warehouses and cold stores, and are the common choice when ambient temperature swings widely. Check the rated ambient range on the datasheet against the coldest and hottest point in the building, not the office temperature.
Maintained or Non-Maintained
A maintained fitting is lit all the time and doubles as normal lighting. A non-maintained fitting sits dark until the supply fails. Non-maintained is cheaper to run and standard in most industrial halls where general lighting already covers the space. Maintained units suit plant rooms, stairwells and corridors where normal lighting may be switched off at night.
The Test Routine
1. Monthly function test: cut the supply to each circuit and confirm every fitting switches to battery and stays lit for a short period.
2. Annual duration test: run each fitting on battery for its full rated duration and record the result.
3. Log every test with date, circuit, result and the action taken on any failure.
4. Replace batteries on the manufacturer’s schedule regardless of test results, since capacity falls gradually and a passing test does not predict the next year.
Automatic self-test fittings write their own log. On a DALI-2 emergency system the results can be read from the controller, which removes the manual walk-round for the function test and keeps the record in one file. For a plant with more than a few dozen fittings, the labour saved usually pays for the difference in fixture cost within a couple of years.
FAQ
Can I use the normal LED panels as emergency lighting? Only if the panel carries an emergency module with its own battery or a central supply, and only if the resulting floor illuminance meets the zone requirement.
How do I know the escape route compliance figure is met? Measure it. Take the illuminance at floor level along the centre line of the route, with the normal supply off, after the fitting has run on battery long enough to stabilise.
Does IP rating matter for emergency fittings? Yes in wet, dusty or washdown areas, because the battery compartment and the electronics sit inside the same housing as the light source.
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