Linsheng – The Meaning Of Emergency Lighting
linsheng stated that emergency lighting is lighting that operates when the main power supply fails. Emergency lighting must include at least emergency escape lighting, which is designed to prevent panic and allow safe passage through buildings, especially in real emergency situations such as fires. However, emergency lighting can also be designed to allow the occupants of the building to “keep”, for example in the event of a main power failure, but without an emergency requiring evacuation. The procedure to be taken during the operation of this “left-behind” strategy will depend on the level of daylighting and whether emergency lighting is provided as full backup lighting or only as emergency safety lighting.
The following are some of the key terms related to emergency lighting design:
Emergency Escape Lighting: Part of emergency lighting that provides illumination for people leaving a location or attempting to terminate a potentially hazardous process (also providing lighting equipment, location and use of safety equipment);
Emergency lighting: Illumination provided when a normal lighting supply fails;
Emergency safety lighting: part of emergency lighting that provides illumination for the safety of personnel living in the home when normal lighting supply fails;
Escape route: Specify a route to a safe place in an emergency;
Final exit: the end of the escape route;
High-risk mission area lighting: Part of emergency escape lighting that illuminates the safety of personnel involved in potentially hazardous processes or situations and makes appropriate closure procedures for the safety of operators and other occupants of the home;
Open area lighting: Provides a portion of emergency escape lighting to avoid panic and provide illumination, enabling people to reach places where escape routes can be identified;
Alternate lighting: Provides a portion of emergency lighting so that normal activities continue to remain substantially unchanged.
Type of emergency lighting
Luminaires (lamps) provide emergency lighting. There are three types, as follows:
Maintaining emergency luminaires is a popular choice for many specifiers because they make the emergency components of the luminaire almost invisible. Typically, emergency operating devices (modules and batteries) are hidden within the luminaire housing or hidden in a remote gearbox in a false ceiling space. The disadvantage is that the lamp is always in use and must be monitored and replaced.
Please note that some emergency lights can also be used as an internal lighting safety sign to mark exit and exit routes. Most people are familiar with the green “EXIT” non-maintenance emergency luminaires that are common on the door. These can also be operated in maintenance mode. Non-maintenance luminaires have lower operating costs and last longer because they are rarely used.
Additional functions, such as a rest mode, may be included to allow the emergency light to be turned off during normal lighting power failure to maintain battery power for emergency evacuation.
High-risk work lighting is emergency lighting designed for high-risk mission areas; it has faster response times than standard emergency lighting.
Duration is the period of time during which the emergency light will run once triggered.
The duration required will depend on the time required to evacuate the home, the size and complexity of the home, and whether it will be evacuated immediately in the event of a supply failure and whether it will be re-occupied as soon as the supply is restored.
The recommended minimum value is an absolute minimum duration of one hour. If it is not expected to evacuate the home immediately in the event of a supply failure, such as sleeping in a shelter or entertainment venue, or if the home is expected to be re-occupied, an emergency lighting time of at least 3 hours should be used. Power is restored without waiting for the battery to charge. If it is expected that the house will be evacuated immediately in the event of a power failure and will not be re-occupied until the battery is fully loaded, only a minimum duration of one hour should be used.
Most systems last for 3 hours
Powering emergency lighting
There are two ways to supply emergency light accessories:
Separately, each accessory is self-contained with its own battery pack that is charged by the power supply during normal operation, sufficient to provide the required duration for powering the accessory in an emergency;
Pass the central power supply (battery or generator).
The advantages of stand-alone accessories are as follows:
Installation is faster and cheaper;
Standard wiring materials can be used without battery ventilation, etc.
Low maintenance costs – only regular testing and general cleaning are required;
Each accessory is independent and the system integrity is higher;
Easy to expand.
The disadvantages are as follows:
Battery life is limited to two to four years,
Testing requires analysis and observation of the luminaire on an individual basis.
Central power supply
The central power supply system has the following advantages:
Maintenance and routine testing are easier because all emergency luminaires can be tested intensively;
The battery can be used for 5 to 25 years;
Large unit batteries are cheaper and the lamps are usually cheaper (although the upfront wiring and installation costs can be high).
The disadvantages are as follows:
The initial installation cost is high, and the wiring of fire-resistant cables for each accessory is much more;
Lower system integrity – failure of the battery or wiring circuit can cause most of the system to fail;
Requires a normally ventilated “battery compartment” to accommodate the battery and charger circuitry;
Local power failures may not trigger emergency lighting operations in the area;
The voltage drop across the luminaire furthest from the central battery can be a problem.
In general, centralized power supply systems are installed on larger projects, where lower maintenance and lower service life are priorities, and the overall project budget can absorb higher system costs. Small and medium business locations typically use a combination of maintenance and non-maintenance independent luminaires.
Testing emergency lighting
Emergency lighting should be tested monthly and an annual “duration” test performed to demonstrate that the lighting can be performed within a specified time (usually 3 hours).
The test should be recorded in the log. See our dedicated emergency light test page for more details. It is important to consider testing during the design phase to ensure that testing does not become more burdensome than it actually needs.