What emergency lighting has to achieve
Emergency lighting is not ordinary lighting that happens to stay on when the power fails. It is a safety system with a defined job: to let people see their way out of a building, and to let them find and use fire-fighting or safety equipment, when the normal supply is lost.
That purpose shapes everything about the design. The luminaires have a dedicated supply, a guaranteed duration, and positions chosen for escape and safety rather than for comfort. In the wider framework of IEC 60364 the system is treated as a safety service, which is why it is separated from the general lighting circuits and protected accordingly.
Getting the design right starts with the escape routes and the safety equipment, not with the fittings. Decide what has to stay lit, and for how long, before choosing any hardware.
The main duty types
Emergency lighting is usually divided by purpose, and each type has its own placement logic.
| Type | Purpose | Typical location |
|---|---|---|
| Escape route lighting | Keep the exit path visible and usable | Corridors, stairs, exits |
| Open area lighting | Stop people being stranded in large spaces | Halls, open-plan floors |
| High-risk task lighting | Allow a dangerous task to be shut down safely | Plant rooms, kitchens |
| Safety sign lighting | Make exit and equipment signs readable | Above doors, at equipment |
A single project often needs more than one type. A small shop may need only escape route lighting and a lit exit sign; a factory floor may need all four.
Minimum duration and autonomy
Emergency lighting must run on its own supply for a defined time after the mains fails. That duration is the autonomy, and it is one of the first numbers fixed in the design because it drives battery size or the sizing of the standby source.
Common durations are one hour and three hours, with the longer periods used where evacuation is slow or where the building may be occupied during a prolonged supply loss. The exact requirement comes from the applicable standard and from the building's use and occupancy, not from a default assumption.
Duration is quoted for the full design load, including signage, so adding fittings late in the project can quietly reduce the autonomy below the required figure. That is one reason the count of luminaires should be settled before the standby source is specified.
How the supply is arranged
Two broad arrangements are used. In a self-contained system each luminaire carries its own battery and charger. In a central system the batteries or the standby generator sit in one place and feed the whole emergency installation.
- Self-contained fittings are simpler to install and easy to relocate, but each one needs to be checked and maintained individually.
- Central systems concentrate maintenance in one location and suit large buildings, but they need dedicated wiring to every luminaire.
- Where a standby generator is used, changeover to it must be automatic and fast enough to keep the escape routes usable.
Whichever arrangement is chosen, the emergency circuits are kept separate from general lighting so that a single fault cannot take both down at once.
Placement and escape route logic
Escape route lighting follows the path a person actually takes, not the geometry of the building plan.
- Illuminate the route itself, including changes of direction, stairs and ramps.
- Cover every exit and the immediate approach to it.
- Light any change of floor level and any obstacle along the route.
- Add lighting and signs at fire-fighting and first-aid equipment.
- Cover intersections and any point where the route is not obvious.
Walking the route on the drawing, and again on site, is the quickest way to catch a gap that a schedule misses.
Testing and verification
A system that is never tested is a system that may not work. Emergency lighting is therefore designed for testing from the start.
- Short functional checks confirm that each luminaire switches to its battery when the supply is interrupted.
- A full-duration test confirms the autonomy, with the fittings run on battery for the whole specified period.
- Results are recorded so that a degraded battery or lamp is visible over time.
Designing with testing in mind — sensible access, clear identification of each emergency circuit and a written schedule of fittings — saves time on every future inspection.
Common design mistakes
Several of the most frequent problems are decisions made too early and never revisited.
- Sizing the battery before the final count of emergency luminaires is known.
- Lighting the plan rather than the escape route, and leaving an exit approach in darkness.
- Sharing a final circuit between emergency and general lighting.
- Forgetting signs at fire-fighting equipment and at changes of direction.
- Leaving the design with no provision for routine testing.
Each of these is cheap to fix on the drawing and expensive to fix after commissioning.
Emergency lighting in the project model
Step back from the fittings and emergency lighting is one more system inside a larger electrical design. In GorkyCAD those systems — power, lighting, boards and cable routes — live in a single model, so the emergency circuit can be traced from the source to each fitting on the same set of drawings. The toolset includes checks against IEC 60364 and a broad set of lighting and load calculations.
Because the model drives the documentation, the emergency schedule and the panel drawing stay consistent with the design as it changes, which is exactly the discipline this kind of safety system depends on.
Next steps
Design emergency lighting from the escape route outward: settle the duty types, fix the duration, choose the supply arrangement, then place the fittings and plan the testing. Everything else follows from those decisions.
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FAQ
How long must emergency lighting last?
It must stay lit for the required autonomy, commonly one hour or three hours, set by the applicable standard and the building's use. The duration applies to the full design load.
What is the difference between escape route and open area lighting?
Escape route lighting keeps the exit path and its signs usable. Open area lighting stops people being stranded in a large space, such as a hall or an open floor.
Should emergency lighting share a circuit with normal lighting?
No. The emergency circuits are kept separate so that one fault cannot disable both the general and the emergency lighting at the same time.
Why test the installation regularly?
Batteries and lamps degrade with age. Short functional checks and a full-duration test show whether each fitting still runs for its specified time, and the results guide replacement.