Emergency lighting is an integral part of a building’s life safety system. Emergency lighting balances the illumination needs when a building’s power supply is interrupted due to utility failure, fire outbreaks, circuit-breaker breakdown, or manual act, including the accidental opening of the switch controlling regular lighting facilities.
These lighting systems aid by providing visibility for occupants evacuating the building, firefighters to coordinate the evacuation, keeping egressing occupants calm and preventing panic stress that can be caused due to darkness. Emergency lighting also reduces workplace accidents during blackouts. Hence undeniably, emergency lighting is a lifeline during a hazard.
Since emergency lighting is intended for safeguarding life, the requirement is regulated by laws. The International Building Codes, NFPA 101, UAE Fire and Life Safety Code, and EN 1838 all outline emergency-lighting requirements. These codes and standards guide and govern all parties involved in the provision of the emergency luminaire, from the manufacturer designing the light fixture to the engineer or specifier preparing the emergency-lighting detail and schedule and the installer or contractor fixing the installation. So, understanding and applying the codes and standards for emergency lighting is crucial for effective emergency-lighting systems.
There are two forms of emergency lighting systems:
1. Stand-by emergency lighting is used where work needs to continue uninterrupted with 100% illuminance during a power-supply failure. This system is used mainly for the healthcare facility and is described in NFPA 99.
2. Emergency lighting that provides illumination for the safe exit of a building is called escape emergency lighting. This system is significant from the point of view of fire-safety provisions; therefore, this article further focuses on the same.
Where must emergency lighting be installed?
Emergency lighting must be installed in all public buildings, including malls, theatres, educational centres, business occupancies, healthcare, residential occupancies, hotels, day-care occupancies, detention, correctional occupancies, etc.
Super high-rise buildings and high-rise buildings – Centrally supplied emergency luminaires are preferred to be installed in super high-rise and high-rise buildings. Malls and amusement buildings will also fall under this category.
Mid-rise buildings, low-rise buildings, warehouses and factories – A monitored-type self-contained emergency lighting system must be provided with dedicated control and monitoring equipment and computer interfacing.
Residential buildings – Emergency illumination systems are compulsory in residential buildings.
It is not mandatory to have emergency luminaires in private and commercial villas; however, it is required in basements and underground parking, if any.
Other occupancies where emergency luminaires are required include business groups, fuel dispensing stations, restaurants, minimarts, etc.
EN 1838 requires the below locations to be considered while installing emergency luminaires in a building:
- Near the exit door
- Near stairs
- Near any change in level
- Externally illuminated escape-route safety signs, escape-route direction signs, and other safety signs
- Change in direction
- At each intersection corridors
- Near each final exit and outside the building to a place of safety.
- Near first-aid post
- Near firefighting equipment or call point
- Near escape equipment provided for disabled people
- Near disabled refugees and call points, etc.
UAE Fire and Life Safety code establishes several additional areas requiring emergency lighting within premises. Emergency lighting must also be installed in the fire pump room, LV room, kitchen delivery areas, indoor loading-unloading areas, transformer rooms, washrooms, etc.
Illumination
Exit signs should identify the entire escape route, including any changes in direction. Exit and directional signs must be illuminated continuously.
The illuminance required on the floor of a corridor-like escape route up to 2m wide should be a minimum of 1 lux along the centreline and a minimum of 0.5 lux in the central band.
Escape routes wider than 2m should be treated as multiple strips of 2m or as open areas.
The egress path must be illuminated at an average level of 10.8 lux, with a minimum of 1.1 lux and a maximum-to-minimum illumination ratio of 40:1.
Open areas, like a room or open space, must have at least 0.5 lux of horizontal illumination at the floor level.
Lighting levels must be at least 15 lux or 10% of the normal lighting levels in high-risk areas.
First-aid posts, fire-alarm call points, firefighting equipment and panels must be provided with vertical illumination of 5 lux.
Duration of emergency luminaires
Emergency luminaires in emergency mode shall be illuminated for a minimum time so that effective evacuation is possible. This minimum amount of time is called ‘Duration’.
NFPA 101 requires the duration of the emergency luminaire as 1.5 hours (90 min), though most evacuations may require more time; therefore, UAE Fire and Life Safety Code mandate the duration as 3 hours (180 min).
The luminaire duration shall be easily identifiable on the product’s label to guide consumers in the correct selection per national regulations.
Self-contained and centrally supplied luminaires
Self-contained luminaires contain all the essential components such as battery, charger, control unit, lamp and any test switch to function as an independent emergency light. These are the most generic type of emergency luminaire.
Centrally supplied luminaires are slave luminaires for maintained or non-maintained operation energised from a central emergency power system that is not contained within the luminaire.
Slave luminaires include the lamp and some control gear, whereas the charger and batteries are located separately and provide the supply power to several luminaires. Central battery emergency luminaires are found in super high-rise buildings, malls, amusement parks, etc.
Testing and maintenance of installed emergency luminaires
Building owners or occupiers must ensure that their emergency lighting systems are maintained in good working condition over the system’s lifetime.
Periodic testing is a requirement to ensure the continued satisfactory operation of emergency lighting systems.
All emergency luminaires undergo a 30-second functional test every month and a 3-hour or 1.5 -hour duration test annually.
The self-tests are popular with inspectors. Evaluating them individually may not be possible in a complex structure with many luminaires. The central monitoring control unit will automatically diagnose the health of batteries, battery output, luminaire output level and circuit integrity, no matter how complicated the system is. All the connected luminaries can be tested through a test feature that simulates the power failure.
Standards
Regulations determine the necessity for emergency lighting, whereas standards assess compliance. Hence different product standards are to be considered while designing emergency lighting systems, including EN/IEC 60598-222, EN 50171, EN 62034, UL 924 etc., which define an emergency luminaire’s
construction, safety, performance and testing requirements.
For more information, email aparna.venugopalan@emirateslaboratory.com or visit www.emirateslaboratory.com
About the Author
Aparna Venugopalan
Aparna Venugopalan is a qualified regulatory, conformity assessment and product compliance specialist with expertise in different product conformity assessment programmes in GCC including Saudi Arabia (SASO), KUWAIT (KUCAS), GMARK, IECEE, UAE Fire and Life Safety Code.Aparna Venugopalan is a qualified regulatory, conformity assessment and product compliance specialist with expertise in different product conformity assessment programmes in GCC including Saudi Arabia (SASO), KUWAIT (KUCAS), GMARK, IECEE, UAE Fire and Life Safety Code.
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