Introduction and discussion on fire emergency lighting design
1 Introduction
In industrial and civil buildings, fire emergency lighting is an important part of the overall security system in the building. Fire emergency lighting design has attracted great attention, especially in some large public buildings, such as office buildings, theaters, libraries, shopping malls, supermarkets, hotels, passenger stations, hospitals and other public places with high density of people, if the emergency lighting design and setting are unreasonable , Once a fire or power failure occurs, it is extremely prone to chaos in the evacuation of people, trampling on each other, etc., resulting in serious casualties.
2 Classification of fire emergency lighting
In order to design more effective and comprehensive emergency lighting, we must first understand the classification of fire emergency lighting. As described in "Civil Building Electrical Design Manual" (Second Edition), it is generally divided into standby lighting, evacuation sign lighting and full lighting.
2.1 Backup lighting
Backup lighting refers to the backup lighting set to continue working (or temporarily continue working) when the normal lighting fails. As the power outage will lead to work interruption or misoperation, and may cause explosion, fire, casualties, or cause serious political consequences and economic losses, consideration should be given to setting up backup lighting for temporary continuation of work. Such as power distribution room, fire control room, operating room and other places must be equipped with backup lighting.
2.2 Evacuation sign lighting
Evacuation sign lighting is a route sign set for people to reach the outdoor or temporary refuge floor under abnormal circumstances (such as fire, accidental power failure, etc.). Such as all exits, all doors, refuge floors, etc. In addition, there are directional signs, that is, pointing by means of arrows or some kind of graphics or text that distinguishes the direction.
2.3 Full lighting
Full lighting refers to the full lighting set to ensure that the personnel in potential danger are fully illuminated when the normal lighting is suddenly interrupted. For example, the operating room of a hospital should be fully illuminated, because an instantaneous power outage will endanger life.
3 Setting of fire emergency lighting
The design of fire emergency lighting is extremely critical in the entire design process. Whether the design is reasonable or not is directly related to whether the fire accident can fully and effectively evacuate the flow of people and whether the firefighting and rescue work can be carried out smoothly.
Article 13.8.2 of "Code for Electrical Design of Civil Buildings" (JGJ 16-2008) stipulates that spare lighting should be provided in places for fire fighting operations and rescue personnel to continue to work, such as fire control room, self-provided power supply room, power distribution room, Fire water pump room, smoke prevention and exhaust machine room, telephone switchboard room, communication room, large and medium-sized electronic computer room, BAS central control station, full prevention control center, and the refuge floor and roof helipad of high-rise civil buildings with a building height of more than 100m etc., and other places that still need to work in the event of a fire; Article 13.8.3 of "Code for Electrical Design of Civil Buildings" (JGJ 16-2008) stipulates that in the evacuation stairwells, smoke-proof stairwell front rooms, Evacuation passages, fire elevator rooms and their front rooms, shared front rooms, audience halls, exhibition halls, multi-function halls, restaurants, banquet halls, conference halls, waiting (machine) halls, business halls, office halls and other high-rise public buildings. Refuge floors (rooms) and other places, exhibition halls, business halls, singing and dancing entertainment, screening and entertainment halls with a construction area of more than 1 500m2, underground buildings with a densely populated area of more than 300m2, studios with an area of more than 200m2, etc., as well as high-rise residences Building evacuation stairwells, inner walkways with a length of more than 20m, fire elevators and their front rooms, and shared front rooms, in addition to evacuation walkway lighting, all exit signs should be installed at all exits and evacuation walkways. and evacuation walkway signs. The operating room of the hospital should be equipped with full lighting, and special lighting fixtures should be used. In the process of fire emergency lighting design, the above regulations must be strictly implemented to ensure that the emergency lighting settings are standardized, reasonable and effective.
4 Installation design of fire emergency lighting fixtures
The backup lighting in emergency lighting should be installed on the wall or ceiling. Evacuation lighting fixtures include all exit sign lights, evacuation indicator lights and evacuation lighting. Generally speaking, the all-exit sign light should be installed above the evacuation door. For the evacuation stairs on the first floor, it should be installed above the inner side of the stairway, and the height of the all-exit sign light from the ground should not be lower than 2m; The location should refer to Figure 13.8.5 of "Code for Electrical Design of Civil Buildings" (JGJ 16-2008), as shown in Figure 1.
Figure 1 Location of evacuation sign lights
The installation design of fire emergency lighting fixtures must meet the relevant regulations in Article 13.8 of "Code for Electrical Design of Civil Buildings" (JGJ 16-2008), and its installation height and position should ensure that in the event of a fire, it can be Quickly and clearly identified.
5 Selection of fire emergency lighting power supply
In the design of fire emergency lighting, the choice of power supply is the top priority in the design. Article 3.2.3.1 of "Code for Electrical Design of Civil Buildings" (JGJ 16-2008) "The fire emergency lighting and evacuation indication signs of Class I high-rise civil buildings shall be Class I load, and the fire emergency lighting and evacuation of Class II high-rise civil buildings shall be The indicator should be the secondary load", Article 3.2.8 of "Code for Electrical Design of Civil Buildings" (JGJ 16-2008) "The primary load should be powered by two power sources, and when one power source fails, the other power source should not be damaged at the same time."
In the electrical design of modern buildings, in addition to the normal mains, the backup power supply for emergency lighting is also called emergency power supply. There are generally two types: diesel generator sets and EPS emergency power supply devices. Under different municipal power supply conditions, please refer to Table 4.1.4 of "National Civil Building Engineering Design Technical Measures-Electrical" (2009) for the configuration requirements of emergency lighting power supply, as shown in Table 1.
Note: A. Two-way independent power supply refers to two-way dedicated power supply drawn from different upper-level substations, or two-way dedicated power supply drawn from different transformer busbar sections of the same substation. The different transformers should be powered by different high-voltage Grid power supply.
B. One line of public power supply refers to the power supply directed from the public trunk line, that is, one line of power supply supplies power to two or more households.
C. Two-circuit power supply refers to the two-way power supply drawn from the same transformer busbar section of the same superior substation, or the two-way power supply drawn from different transformer busbar sections, but the transformer is powered by the same high-voltage power grid.
D. Two-way low-voltage power supply refers to two-way low-voltage 220/380 power supply, and the two-way low-voltage power supply should be derived from two different transformer busbar sections of the substation.
①Dual mains + generator + EPS refers to the emergency power supply system composed of dual mains, generator and EPS. ②Dual mains + EPS refers to the emergency power supply system composed of two high-voltage power supplies and EPS. ③ Mains + generator + EPS refers to the emergency power supply system consisting of one mains, generator and EPS. ④ Mains + EPS refers to the emergency power supply system composed of mains and EPS. ⑤Dual mains power supply refers to the emergency power supply system composed of two mains mains power supply, without EPS power supply device.
6 Design Examples
The author is responsible for the electrical design of a five-star hotel in a city in Guangxi. The hotel integrates shopping, catering, recreation, conferences, and accommodation, with a construction area of 45 069m2 and a first-class high-rise building with a building height of 92.90m. The emergency lighting power is primary load. In the design of this project, the emergency lighting part is a self-contained power distribution system, which is provided by the mains and diesel generators to provide dual power supplies, and is powered by tree trunks. The emergency lighting power supply in this partition, and in each emergency lighting fixture, are equipped with batteries. The diesel generator set can pick up the delay time of the diesel generator from the dual power transfer switch side (mains side) when the mains power failure, phase loss, voltage or frequency is out of range, or when two transformers in the substation fail at the same time. The start signal is sent to the diesel generator room, and the signal delay is 0~10s (adjustable) to automatically start the diesel generator set. After the diesel generator set reaches the rated speed, voltage and frequency within 30s, it will be put into operation with rated load. When the mains is restored for 30s ~ 60s (adjustable), the mains power supply will be automatically restored, and the diesel generator set will automatically shut down after the cooling delay to ensure the reliability of the power supply.
Emergency lighting, also called accident lighting. In the design of this project, the author has fully considered the specific situation of the fire, not only the situation when the power is suddenly cut off during the non-fire. As we all know, in a fire, the power supply lines and electrical appliances are usually damaged first. Once these devices are damaged, it is easy to cause short circuits, overloads, etc. Includes emergency circuit. In addition, in practice, when a fire breaks out in a building, water is often used as a fire extinguishing medium. In order to prevent firefighters and other personnel on site from risking electric shock, it is also necessary to manually cut off the power supply and then put out the fire, including the firefighting power supply; During the process, the fire water will inevitably wet the equipment and lines, which will cause short circuits and leakage, and then cause tripping and power outages. Therefore, due to the above reasons, following the design concept of "people-oriented, life first", when designing the emergency lighting system of this project, in addition to providing dual power supplies in the terminal emergency lighting distribution box, in each emergency lighting fixture, All batteries are attached, and the continuous power supply time of the battery is required to be no less than 30 minutes, of which the substation, generator room, water pump room, and fire control room are required to be no less than 180 minutes to ensure that emergency lighting is provided when the above worst situation occurs. The lamps can still work normally, maximizing the needs of lighting and power supply for full evacuation, and ensuring the safety of personnel. In the design of this project, the author realized the effective combination of the centralized power supply of emergency lighting power and the independent decentralized power supply of a single lamp, which minimized the dependence of emergency lighting equipment on the integrity of power supply lines, and ensured the reliability of emergency lighting power supply. Thus protecting people's lives.
