Emergency Lighting Systems for Buildings
Emergency lighting systems in buildings are rarely used but absolutely necessary. When the main power goes out, these units provide light to a safe passage. When the fire alarm bells are ringing and smoke is in the air, these backup lights save lives by preventing people from panicking.
Emergency lighting illuminate safe exit routes out of commercial buildings.
Emergency lighting is a part of a building's life safety system and are standard features in commercial, industrial and multi-residential buildings. After the main power is cut by fire, they provide illumination for a minimum of 30 minutes to allow the building to be evacuated.
Most times the emergency lights are separate from exit signs. and their purpose is to:
- Illuminate the path along the exit routes, especially in hallways, office spaces and floor spaces with large occupancy levels
- Provide a minimum level of lighting in the most populated areas of the building
- Highlight equipment hazards and falling hazards such as stairways
- Keep people calm when the main lights go out
- Emphasize muster areas as people instinctively 'head towards the light' during a crisis.
Emergency lighting is required in high-occupancy residential buildings. The suites do not require emergency lamps but the common areas, corridors and stairwells do.
Emergency lights are powered by a battery-backup system that switch on automatically in a power outage. Remote lamp heads use separate conductors (usually DC) from the main lighting circuits and are spread throughout the tenant space.
Most modern installations use low power, high output LED lamps while the older units still use the incandescent spot lights. All units have a reflector and lens to focus the light along a pathway, not a flood light.
As electrical engineering consultants, we design emergency lighting systems to meet the minimum requirements set out in the building code, fire code and Canadian Electrical Code and then customize the system to the client's situation, special hazards and path of egress.
Emergency lighting are out of site but always on the ready to provide safe illumination.
For instance, in a parcel sorting plant, when the main power is interrupted, the warehouse area will be lit to a minimum of 1 lux while the areas around the conveyors will have added emergency lights to allow workers to safely evacuate from the machinery.
In Alberta and BC, a minimum of 30-120 minutes of battery power is required for these systems, depending on the building designation. Their emergency power source can be a battery or a back up generator, the latter not being as common in this part of Canada.
BC Building Code / Alberta Building Code Requirements for Emergency Lighting Systems
Both provinces base the requirements for emergency lighting systems on the National Building Code of Canada. There are some minor differences between the provinces but the main similarities of Section 18.104.22.168 that pertain to Part 3 buildings are:
- Average illumination level not less than 10 lx at floor or tread level with the minimum value at 1 lx.
- Principal routes providing access to exits in open floor areas shall be lit.
- Emergency lighting in service rooms. We usually provide emergency lighting beyond the minimum stated duration since this is where work on the critical building systems take place.
- Corridors servicing sleeping rooms for certain types of building occupancy.
- Corridors servicing classrooms, underground walkways and public corridors.
- Floor areas of certain types of building occupancy.
- Food preparation areas in commercial kitchens.
- Emergency lighting in treatment centres also must conform to CSA Z32, "Electrical Safety and Essential Electrical Systems in Health Care Facilities."
BC Fire Code Requirements for Emergency Lighting
- Each remote must have a backup bulb meaning that you will always see a two lamp unit. Single head units do not provide redundancy for evacuation purposes.
Canadian Electrical Code Requirements for Emergency Lighting
The circuits that power the emergency lighting system must conform to the Canadian Electrical Code section 46. The following requirements are necessary:
Depending on the type of building, emergency lights provide 30 minutes of light after the power goes out.
- 46-304(4) - The emergency lighting equipment will automatically activate upon failure of the power supply to the normal lighting circuit in the area. Multiple battery backup units should be distributed across the normal lighting circuits to allow for select operation if individual circuits fail, not just the main power source.
- Some systems have a central battery bank storage but these are more complicated to provided coverage for outages for local lighting circuits, as just discussed.
- Battery backup ballasts are available from manufacturers but are not popular in Canada as of yet. These may be used in stairways to simply the electrical distribution for the lighting circuits but are not in major use as of yet.
- The wiring for the emergency lighting circuit should be kept separate from the normal lighting so damage to the main lighting conductors will not knock out the emergency lights as well.
- Equipment must be mounted not less than 2 m above the floor (measured from the floor to the bottom of the equipment).
- Receptacles for these battery-backed units shall not be less than 2.5m above the floor and not more than 1.5m from the location of the equipment.
- Permanent connections, not a receptacle, are required for units operating off of 250V or higher or if the AC current draw is more than 24 A.
In some areas of western Canada, power outages are frequent, especially in northern Alberta, the BC coast and Vancouver Island. Depending on the outage duration and the associated risk to those in the building, we use our engineering discretion in determining the type of back power system for the emergency power. This may be more stringent than the minimum set forth in the code to ensure safety. It's important to work with the local fire safety and building inspectors in these rare circumstances (see BCBC/ABC Appendix A-22.214.171.124(1).
The building codes require that your emergency lighting systems be tested monthly to ensure safe operation when really needed. This testing is usually done by electrical contractors and fire alarm companies.
Emergency lightings are essential components of a building's life safety system and are the last systems operating when emergency situations occur. Let's keep lives and livelihoods safe.