Emergency Stairwell Lighting During a Power Outage

Two approaches: self-contained luminaires and a central source

There are two fundamentally different ways to provide light on the stairs. The first: self-contained luminaires with a built-in battery that switch on when voltage disappears. The second: a central source that feeds dedicated emergency lighting circuits. The choice depends on the number of floors, the current state of the wiring and the requirements of the safety design.

Which requirements are important to clarify

Requirements for evacuation and emergency lighting are set by building and fire codes and by the design of the specific building. On this page we do not quote figures from the codes, because we have not checked them against the current edition of the documents. The board should ask the design engineer or a fire safety specialist which codes the building complies with and what its design requires.

• Which areas must be lit: stair flights, landings, the exit outside, evacuation routes.
• The minimum operating time from backup according to the design.
• Whether the building has evacuation direction signs and whether they have separate backup power.
• Who keeps the system inspection log and how often.

How much energy this needs: orders of magnitude

Emergency stairwell lighting needs little energy: modern LED luminaires consume little, so unlike elevators or pumps, power is not the problem. A hypothetical example, not the characteristics of real devices: suppose the building has five floors with three 10 W luminaires per floor, so the total power is 150 W. For one hour of outage that is 150 Wh, and for eight hours 1.2 kWh before accounting for margins and inverter losses.

This figure is small compared with elevator consumption, so emergency lighting is usually part of the first phase of any backup system. If the building gets a central inverter, the emergency lighting circuit is added to the list at the highest priority, not together with the rest of the lighting.

Maintenance: what is forgotten most often

Batteries in self-contained luminaires degrade, and without checks nobody knows whether they work. So the board should have a simple procedure: an inspection calendar, a responsible person, a log and a stock of replacement cells. Luminaires have a test function; its purpose and how to trigger it are described in the datasheet.

1. Inventory. Count all emergency luminaires and note the type, installation date and whether there is a test function.
2. Outage test. At an agreed interval, simulate a loss of voltage following the manufacturer’s instructions and record the result.
3. Replacement. Replace faulty luminaires or power cells according to the datasheet, recording the date.
4. Report to residents. Post a short confirmation in the shared chat or on the notice board that the system has been checked.

Stairwell zones: where light is needed most

Not all areas are equally important. The greatest risk comes from stair flights and landings, level changes, exits outside and vestibules, where the lighting changes sharply. In the basement and on the technical floor there are additional hazardous places with stray objects and equipment. Walk through the building in the evening with the lights off and note the places where it becomes truly dangerous without light: this is a cheaper and more accurate way to set priorities than assumptions on paper.

The result of the walkthrough should form the basis of the circuit list: put emergency circuits for flights and exits at the highest priority and add the rest on a residual basis. That way ordinary luminaires in floor corridors will not drain the capacity.

Typical mistakes

• Installing luminaires and not drawing up an inspection schedule.
• Connecting the emergency circuit to the general panel without separation, so that it depends on the same circuit breaker.
• Forgetting vestibules, exits and basement rooms.
• Assuming that yard and stairwell lighting need the same priority, and spending capacity on secondary needs.
• Not recording who is responsible for the tests after the board changes.

Short checklist

Frequently asked questions

Are self-contained luminaires enough if the building plans central backup?

Possibly, but only if the safety design allows it. A central system reduces the number of separate batteries, but the choice must be agreed with the design engineer and a fire specialist.

How often should emergency lighting be checked?

The frequency is set by the manufacturer’s datasheet, the building design and the requirements a specialist will give you. The main rule: the check must be scheduled and the result recorded.

Next steps

Preliminary backup power calculationPrepare a fundraiser for the OSBB