Discussion on emergency lighting? [Daily Question 090314]

Emergency lighting is used for personnel evacuation, to ensure safety, or to allow continued work when the normal lighting system fails to provide adequate light due to a power outage. 　　Emergency lighting is different from regular lighting; it includes three types: backup lighting, evacuation lighting, and safety lighting. Determination of conversion time The conversion time is determined in accordance with the actual project requirements and relevant specifications. 　　(1) The switching time for backup lighting should not exceed 15 s ； 　　(2) The switching time of the evacuation lighting shall not exceed 15 s ； 　　(3) The switching time of the safety lighting should not be greater than 0.5s ； Based on the types of emergency lighting power supplies and the requirements regarding switching time, it is clear that the duration for which emergency lighting can operate is subject to certain constraints. It is generally stipulated that the operating time of evacuation lighting should not be less than 30 minutes; depending on various requirements, it can be divided into 6 categories: 30, 60, 90, 120, and 180 minutes. The continuous operating time for backup lighting and safety lighting should be determined based on the specific requirements of the location where it is used. For emergency lighting systems powered from the power grid or generator sets, their operational duration can easily meet the requirements ； For emergency lighting systems powered by batteries, their operation time is limited by the battery capacity; in locations where a longer operating time is required, battery packs should not be used alone, and it is advisable to consider using them in combination with generator sets. In this case, powered by a battery pack, it is used only as a temporary solution for emergency lighting; therefore, its operating time can be appropriately reduced. When selecting a power supply for emergency lighting, the continuous operation time should be determined based on specific circumstances. As for the wiring requirements for emergency lighting, they have not been found yet. This post was last edited by jingsan on 2009-3-14 09:43]

1. What are the types of emergency lighting? The request must be justified. Emergency lighting includes the following types: A. Backup lighting designed to enable continued operation (or temporary continued operation) in the event that normal lighting fails ； 　　B. Evacuation lighting designed to enable people to safely exit indoors and reach the outside (or a safe area) in case of a fire ； 　　C. Safety lighting installed to ensure the safety of people in potential danger in the event of a sudden interruption of normal lighting. 2. What are the wiring requirements for emergency lighting? The request must be justified. A. The charging cable for emergency lights equipped with batteries must not be disconnected under any circumstances, and this should be clearly indicated in the labeling box of the distribution panel. 　　B. Both the charging cable and the contactor circuit should be equipped with circuit protection switches. 　　C. Emergency lighting fixtures installed at a height of less than 2.4 meters should be equipped with a PE wire. 3. What are the activation time and operating time of emergency lighting? The request must be justified. A. Startup time: The power-on time for backup lighting and evacuation lighting should not exceed 15 seconds; (the startup time for backup lighting used for anti-theft purposes should be within 1.5 seconds.) ； The power switching time for safety lighting should not exceed 0.5 seconds. B. Backup lighting must continue to operate for at least 8 hours ； The backup lighting for temporary use should be able to continue operating for more than 1 hour; evacuation lighting and safety lighting should be able to continue operating for more than 20 minutes ； For buildings with a height of over 100m, the duration should be no less than 30 minutes (according to the requirements of \"Emergency Lighting for Fire Fighting\" (GB17945-2000), the operating time of standard emergency lighting fixtures must be no less than 90 minutes).

There are 1 type each for backup lighting, evacuation lighting, and safety lighting; their switching times should be no more than 15 s, 15 s, and 0 s respectively

I. Classification 1. According to GB7000.2-1996 \"Safety Requirements for Emergency Lighting Fixtures\", emergency lighting includes evacuation lighting and standby lighting. 2. According to the \"Guidelines for Emergency Lighting Design\", emergency lighting includes evacuation lighting, safety lighting, and backup lighting. 3. According to the \"General Technical Requirements for Fire Emergency Lighting Fixtures\", Category 4, Subsection 4.1: Classified by emergency power supply method as follows: a. Self-powered type ； b. Centralized power supply type ； 4.2 Classified by purpose: a. Evacuation indicator lights ； b、 Evacuation lighting lamps ； 4.3 Classified by operation mode: a. Continuous ； b. Non-continuous. II. Wiring requirements for emergency lighting: According to section 6.4.1 of the \"Emergency Lighting Design Guidelines\", the wiring method to be used is as follows: a. When there are two or more transformers in a building, each connected to a different high-voltage power source, the emergency lighting system should be connected to a different transformer from that used for the normal lighting. b. When a dedicated emergency power supply or backup power source from the power grid is available inside or near the building, the emergency lighting shall be powered by that dedicated emergency power supply or backup power source. c. When the power supply within a building (including substations or low-voltage power supplies) is powered by only one high-voltage power source, the emergency lighting shall be supplied by a substation located near the building and connected to another high-voltage power source. d. When the above conditions are not met and there is only one high-voltage power supply, the backup lighting power supply can be determined based on the importance of the location. For areas where the potential hazards and losses are minimal, the backup lighting and the regular lighting can be powered by different transformers connected to the same high-voltage power supply, or by different low-voltage distribution circuits from the same transformer. 7.2 Installation of emergency lighting circuits 7.2.1 The installation of emergency lighting circuits in different types of environments shall comply with the requirements of relevant specifications. 7.2.2 In the event of a failure in the normal lighting circuit, it shall not affect the operation of the emergency lighting; its installation shall meet the following requirements: a. The emergency lighting circuit and the normal lighting circuit shall be installed separately, and shall not be run in the same conduit. b. The emergency lighting circuit shall not share a neutral wire with the normal lighting circuit. When the protective earth wire (PE wire) of the power distribution system used is not combined with the neutral wire (N wire) into a single wire, the protective earth wire (PE wire) can be shared. c. The emergency lighting distribution box should be installed separately from the normal lighting distribution box, and in a location free from fire hazards. 7.2.3 The evacuation lighting circuits and the backup lighting circuits for the areas specified in item d of 5.4 shall, in addition to meeting the requirements of 7.2.2, also comply with the following requirements: a. The lighting branch circuits shall be divided according to fire compartments, and should not cross them; where it is necessary for the main power distribution circuits to cross such compartments, thermal insulation and fire protection measures shall be taken. b. The circuit should not pass through flammable areas, such as warehouses of combustible materials. c. Ordinary wires and cables can be used for the wiring, but they should be protected by metal tubes or flame-retardant rigid plastic wire conduits. When installed concealed, it should be placed within a non-combustible structure, and the thickness of its protective layer should not be less than 30 mm ； When installed openly, fire protection measures should be taken on the outer wall of the metal pipe, such as applying acrylic latex fire-resistant coating. d. When flame-retardant or heat-resistant cables are used, they can be installed in cable shafts, cable tunnels, cable trays, or cable trenches with fire-resistant properties. The walls and covers of such shafts, tunnels, and trenches must have the same fire resistance rating as the building itself, and the doors of the shafts should be fire-resistant doors. When fire-resistant cables or flame-retardant cables/wires are used for the wiring, they can be installed openly on non-combustible or slowly combustible components; however, the flame-retardant duration of such cables and wires must not be shorter than the duration of emergency lighting. e. When cables and wires pass through walls or floor slabs, they should be protected by metal tubes; the joints between the tubes and the walls or slabs must be sealed tightly, and the inside of the tubes should be filled with non-flammable materials. f. For particularly important buildings, fire-resistant cables should be used for the main circuits that supply power to emergency lighting. III. Activation time and operating time of emergency lighting 1. In accordance with Requirement 5.1 of the \"General Technical Conditions for Fire Emergency Lighting Fixtures,\" the emergency switching time for such fixtures shall not exceed 5 seconds. 5.2 The emergency operation time of fire emergency lighting fixtures shall be no less than 30 minutes. 2. In accordance with the requirements of \"Fire Emergency Lighting Fixtures\" (GB17945-2000), the operating time of standard emergency lighting fixtures shall be no less than 90 minutes.

1. Classification of emergency lighting； 1) Classified by emergency power supply type:　　　a. Self-powered type　　　b. Centralized power type　　　c. Mother-child power type 2) Classified by purpose:　　　a. Sign lights　　　b. Lighting lamps　　　c. Both lighting and sign lights 3) Classified by operation mode:　　　a. Continuous type　　　b. Non-continuous type 4) Classified by emergency implementation method:　　　a. Independent type　　　b. Centralized control type　　　c. Mother-child control type 2. Requirements for emergency lighting 1) Requirements for illuminance According to CIE test results, people are highly likely to collide with obstacles when the illuminance is below 0.2 LX; at 0.5 LX, it is possible to avoid collisions with obstacles to some extent. The higher the illuminance, the more agile and confident people’s movements become. Generally, an illuminance of at least 10 LX or 10% of the normal lighting level is considered satisfactory. Furthermore, due to the sudden disappearance of normal lighting, the illuminance drops significantly, and it takes some time for human eyes to adapt and regain their ability to see properly. The CIE also specifies a lighting ratio of 40:1; for large areas with high foot traffic such as shopping malls and theaters, it is appropriate to raise the evacuation illuminance to between 5LX and 11LX. 2) Time requirements: The switching-on time for our current fire emergency lighting fixtures is generally around 1 second, which is usually sufficient to meet the requirements. Meanwhile, to allow all people to evacuate the area, a certain amount of time is needed; this time varies depending on the specific location, with a standard requirement that the emergency lighting should be operational for at least 1.5 hours. 3) Emergency sign lights and emergency lighting should be used in combination; it is unreasonable to focus only on the design of emergency sign lights while neglecting the design of emergency lighting, or to focus only on the design of emergency lighting while ignoring the design of emergency sign lights. 4) Emergency power supply and control: ① In the event of a fire in a building, it may cause short circuits in electrical circuits and failures in other equipment. Electrical circuits can contribute to the spread of the fire, and during rescue operations, contact with live, leaking equipment or circuits may result in injuries or deaths. Therefore, after a fire breaks out, firefighters must first cut off the main power supply before attempting to extinguish the fire to ensure safety. Hence, using a power supply with a voltage of over 220V as an emergency power source is unreasonable. This is because, unlike regular fire-fighting power distribution systems, emergency lighting fixtures are installed in many locations throughout the building, covering virtually all public areas. The wiring is arranged in various directions, and most of these fixtures are located inside ceilings. In practice, most of the wiring for emergency lighting does not have any fireproofing measures in place. Even if some fireproofing measures are applied to the wiring, it is very difficult to ensure that the hoses leading to the fixtures, junction boxes, connectors, and the fixtures themselves are also properly fireproofed. b. In the event of a fire, the ceiling is highly prone to burning. Under such circumstances, pipes break and lighting fixtures shatter. If the sprinkler system and fire suppression system are activated at this time, large amounts of water will flow into the vertical areas on each floor. The 220V power supply could then pose a serious threat to the lives of those evacuating and firefighters, and it might also cause the fire to spread to other areas due to short circuits in the emergency lighting circuits. C. Due to the complex conditions at the fire scene, it is most likely that this section of the wiring will short-circuit and catch fire, generating a large fault current that can affect the operation of other fire-fighting equipment or potentially cause the fire to spread. Based on the above analysis, it is unreasonable to use a 220V urban power grid supply, as well as generator set power or a transformer to convert the voltage to 36V; it is better to employ an independent emergency power source. ②The most fundamental principle of emergency lighting is that, in the event of a fire, all evacuation sign lights as well as the lighting fixtures along the evacuation routes should be activated immediately under the control of the fire control center, right after the normal lighting is turned off. These lights should not be controlled by nearby switches and must remain lit at all times to facilitate the immediate evacuation of people. It would be highly impractical to require those who need to evacuate to turn on the lighting switches first before evacuating.

I. Classification 1. According to GB7000.2-1996 \"Safety Requirements for Emergency Lighting Fixtures\", emergency lighting includes evacuation lighting and standby lighting. 2. According to the \"Guidelines for Emergency Lighting Design\", emergency lighting includes evacuation lighting, safety lighting, and backup lighting. 3. According to the \"General Technical Requirements for Fire Emergency Lighting Fixtures\", Category 4, Subsection 4.1: Classified by emergency power supply method as follows: a. Self-powered type ； b. Centralized power supply type ； 4.2 Classified by purpose: a. Evacuation indicator lights ； b、 Evacuation lighting lamps ； 4.3 Classified by operation mode: a. Continuous ； b. Non-continuous. II. Wiring requirements for emergency lighting: According to section 6.4.1 of the \"Emergency Lighting Design Guidelines\", the wiring method to be used is as follows: a. When there are two or more transformers in a building, each connected to a different high-voltage power source, the emergency lighting system should be connected to a different transformer from that used for the normal lighting. b. When a dedicated emergency power supply or backup power source from the power grid is available inside or near the building, the emergency lighting shall be powered by that dedicated emergency power supply or backup power source. c. When the power supply within a building (including substations or low-voltage power supplies) is powered by only one high-voltage power source, the emergency lighting shall be supplied by a substation located near the building and connected to another high-voltage power source. d. When the above conditions are not met and there is only one high-voltage power supply, the backup lighting power supply can be determined based on the importance of the location. For areas where the potential hazards and losses are minimal, the backup lighting and the regular lighting can be powered by different transformers connected to the same high-voltage power supply, or by different low-voltage distribution circuits from the same transformer. 7.2 Installation of emergency lighting circuits 7.2.1 The installation of emergency lighting circuits in different types of environments shall comply with the requirements of relevant specifications. 7.2.2 In the event of a failure in the normal lighting circuit, it shall not affect the operation of the emergency lighting; its installation shall meet the following requirements: a. The emergency lighting circuit and the normal lighting circuit shall be installed separately, and shall not be run in the same conduit. b. The emergency lighting circuit shall not share a neutral wire with the normal lighting circuit. When the protective earth wire (PE wire) of the power distribution system used is not combined with the neutral wire (N wire) into a single wire, the protective earth wire (PE wire) can be shared. c. The emergency lighting distribution box should be installed separately from the normal lighting distribution box, and in a location free from fire hazards. 7.2.3 The evacuation lighting circuits and the backup lighting circuits for the areas specified in item d of 5.4 shall, in addition to meeting the requirements of 7.2.2, also comply with the following requirements: a. The lighting branch circuits shall be divided according to fire compartments, and should not cross them; where it is necessary for the main power distribution circuits to cross such compartments, thermal insulation and fire protection measures shall be taken. b. The circuit should not pass through flammable areas, such as warehouses of combustible materials. c. Ordinary wires and cables can be used for the wiring, but they should be protected by metal tubes or flame-retardant rigid plastic wire conduits. When installed concealed, it should be placed within a non-combustible structure, and the thickness of its protective layer should not be less than 30 mm ； When installed openly, fire protection measures should be taken on the outer wall of the metal pipe, such as applying acrylic latex fire-resistant coating. d. When flame-retardant or heat-resistant cables are used, they can be installed in cable shafts, cable tunnels, cable trays, or cable trenches with fire-resistant properties. The walls and covers of such shafts, tunnels, and trenches must have the same fire resistance rating as the building itself, and the doors of the shafts should be fire-resistant doors. When fire-resistant cables or flame-retardant cables/wires are used for the wiring, they can be installed openly on non-combustible or slowly combustible components; however, the flame-retardant duration of such cables and wires must not be shorter than the duration of emergency lighting. e. When cables and wires pass through walls or floor slabs, they should be protected by metal tubes; the joints between the tubes and the walls or slabs must be sealed tightly, and the inside of the tubes should be filled with non-flammable materials. f. For particularly important buildings, fire-resistant cables should be used for the main circuits that supply power to emergency lighting. III. Activation time and operating time of emergency lighting 1. In accordance with Requirement 5.1 of the \"General Technical Conditions for Fire Emergency Lighting Fixtures,\" the emergency switching time for such fixtures shall not exceed 5 seconds. 5.2 The emergency operation time of fire emergency lighting fixtures shall be no less than 30 minutes. 2. In accordance with the requirements of \"Fire Emergency Lighting Fixtures\" (GB17945-2000), the operating time of standard emergency lighting fixtures shall be no less than 90 minutes.

According to the Emergency Lighting Guidelines, 1. What are the types of emergency lighting? Scope of the Emergency Lighting Guide: This guide applies to the design of indoor emergency lighting in new, expanded, and renovated civil and industrial construction projects. Purpose of the Emergency Lighting Guide: a. To provide recommended practices for the design of emergency lighting (including evacuation lighting, safety lighting, and backup lighting). b. Put forward safety and technical requirements for evacuation sign lights (including evacuation exit sign lights and evacuation direction sign lights). 2. What are the wiring requirements for emergency lighting? 6.4.1 Wiring method adopted: a. When there are two or more transformers in a building, each connected to a different high-voltage power source, the emergency lighting should be connected to a different transformer from that used for normal lighting. b. When a dedicated emergency power supply or backup power source from the power grid is available inside or near the building, the emergency lighting shall be powered by that dedicated emergency power supply or backup power source. c. When the power supply within a building (including substations or low-voltage power supplies) is powered by only one high-voltage power source, the emergency lighting shall be supplied by a substation located near the building and connected to another high-voltage power source. d. When the above conditions are not met and there is only one high-voltage power supply, the backup lighting power supply can be determined based on the importance of the location. For areas where the potential hazards and losses are minimal, the backup lighting and the regular lighting can be powered by different transformers connected to the same high-voltage power supply, or by different low-voltage distribution circuits from the same transformer. 3. What are the activation time and operating time of the emergency lighting? The request must be justified. 6.1 For normal power failures, the transition time required to switch to emergency power supply is as follows: a. The evacuation lighting should take no more than 15 seconds. When possible, the conversion time should be shortened. b. The safety lighting duration should not exceed 0.5s. c. The standby lighting should not exceed 15 seconds. Primarily due to the need for proper operations and handling, as well as to avoid accidents and economic losses, certain locations require a shorter switching time; for example, the time required at cash registers in shopping malls should not exceed 1.5 seconds ； For production sites with serious hazards, it shall be determined according to the actual production needs. 6.2 In the event of a normal power failure and operation from emergency power supply, the required duration of operation for emergency lighting is as follows: a. The evacuation lighting should last no less than 30 minutes. Depending on different requirements, it can be divided into 6 settings: 30, 45, 60, 90, 120, and 180 minutes. b. The continuous operating time of safety lighting and backup lighting shall be determined based on the specific requirements of use.

According to GB17945-2000 for fire emergency lighting: 1. What are the types of emergency lighting? Fire emergency lighting fixtures: Various types of fixtures that provide markings and/or illumination for the evacuation of people and for firefighting operations in case of a fire. Fire emergency lighting lamps: Fire emergency lighting fixtures that provide illumination for the evacuation of people and/or for firefighting operations. Fire emergency sign lamps: Fire emergency lighting fixtures that use graphics and/or text to fulfill the following functions: a) indicating safe exits and their directions; b) indicating floors with shelters and other safe locations; c) indicating the location and direction of fire extinguishing equipment; d) indicating areas where entry is prohibited and locations where hazardous materials are stored. Fire emergency lighting and sign lamps: Fire emergency lighting fixtures that combine the functions of both fire emergency lighting lamps and fire emergency sign lamps. 2. What are the wiring requirements for emergency lighting? Self-powered type, centralized power supply type, master-slave power supply type. 3. What are the startup time and operating time of emergency lighting? The emergency switching time of fire emergency lighting fixtures should be no more than 5 seconds; for those used in high-hazard areas, this time should be no more than 0.25 seconds. The emergency operation time of such lighting fixtures should be at least 45 minutes, and it must also be equal to or greater than the emergency operation time specified by the fixture itself

Taking these three criteria into account: Startup time: the shortest is 0.25 seconds, with an average of 5 seconds. Power supply/wiring method: it can be either a unit with its own power source, an independent transformer, or centralized power supply. Type: all are lighting systems designed for fire evacuation purposes. In my opinion, emergency lighting is intended to enable people to quickly locate relevant emergency equipment and evacuation routes in case of an emergency, serving as a safety indicator and an auxiliary to fire signs. For this question, the answer from floor 6 was quite thorough, and floor 8 provided a good explanation of the requirements regarding power supply. Reference from Floor 8: Emergency power supply and control: ① In the event of a fire in a building, it may cause short circuits in electrical wiring and other equipment failures. Electrical wiring can contribute to the spread of the fire, and during rescue operations, contact with live, leaking equipment or wiring may result in casualties. Therefore, after a fire breaks out, firefighters must first cut off the main power supply before attempting to extinguish the fire to ensure safety. Hence, using a power supply with a voltage of over 220V as an emergency power source is unreasonable. This is because, unlike regular fire-fighting power distribution systems, emergency lighting fixtures are installed in many locations throughout the building, covering virtually all public areas. The wiring is arranged in various directions, and most of these fixtures are located inside ceilings. In practice, most of the wiring for emergency lighting does not have any fireproofing measures in place. Even if some fireproofing measures are applied to the wiring, it is very difficult to ensure that the hoses leading to the fixtures, junction boxes, connectors, and the fixtures themselves are also properly fireproofed. b. In the event of a fire, the ceiling is highly prone to burning. Under such circumstances, pipes break and lighting fixtures shatter. If the sprinkler system and fire suppression system are activated at this time, large amounts of water will flow into the vertical areas on each floor. The 220V power supply could then pose a serious threat to the lives of those evacuating and firefighters, and it might also cause the fire to spread to other areas due to short circuits in the emergency lighting circuits. C. Due to the complex conditions at the fire scene, it is most likely that this section of the wiring will short-circuit and catch fire, generating a large fault current that can affect the operation of other fire-fighting equipment or potentially cause the fire to spread. Based on the above analysis, it is unreasonable to use a 220V urban power grid supply, as well as generator set power or a transformer to convert the voltage to 36V; it is better to employ an independent emergency power source. Last edited by Striving for victory in solitude on 2009-3-14 20:45]