With the continuous deepening and development of China's reform and opening up and the arrival of the new century, all walks of life are undergoing rapid changes. The rise and change of the construction industry is rapid and diverse. Modern buildings are different in shape and shape, and gradually It presents high, large, full and new features. Modern buildings have higher and higher layers, larger and larger areas, more and more internal facilities, new and new equipment and materials, and safety, flexibility and comfort. The level is also getting higher and higher. Building electrical is undoubtedly a very important part of measuring building standards. As a branch of building electrical, emergency lighting is also an important safety facility in modern architecture. Especially in the event of a fire or power failure in a public building, emergency lighting plays an important role in evacuating personnel, firefighting and rescue work, ensuring personal safety, performing necessary operations or maintaining work. In the following, I will only talk about emergency lighting about some of my experiences and opinions in design work and engineering practice. Please pay attention to criticism and correction.
First, the classification of emergency lighting
Emergency lighting is defined in the "Design Code for Civil Building Lighting" î—¤ GBJ133-90 is: lighting that is activated due to the failure of normal lighting power supply, also known as accident lighting. The standard and the International Commission on Illumination CIE publication "Guidelines for Emergency Lighting in Buildings" divide emergency lighting into evacuation lighting, safety lighting, and standby lighting. However, the International Electrotechnical Commission's IEC "Emergency Lighting" standard attributes safety lighting to standby lighting, which is divided into evacuation lighting and standby lighting. According to the relevant regulations of China, there are differences between the safety lighting and the standby lighting in the setting place and the handling method. Therefore, it is more appropriate to separate the two.
According to "Design Standards for Civil Building Lighting" î—¤ GBJ133-90 Article 4.1.2: "Lighting categories can be divided into normal lighting, emergency lighting, duty lighting, security lighting and obstacle lighting. Emergency lighting can include evacuation lighting, safety lighting and standby Lighting." For this emergency lighting, it can be understood as: the lighting that continues to work, personnel safety or smooth evacuation after the normal lighting system is extinguished due to the failure. Therefore, the emergency lighting design in the project must not only meet the requirements of the fire emergency lighting system required by the fire protection specification, but also meet the requirements of the overall emergency lighting system of various specifications and standards. Of course, the principle of setting emergency lighting, from the perspective of safety, there should be more building emergency lighting; from an economic point of view, it can only be set in some of the most needed buildings.
4. Determination of emergency lighting power supply mode
The selection of emergency lighting power supply mode should be determined by considering various types of emergency lighting, conversion time, continuous working time, various power supply characteristics and actual engineering requirements, etc., to achieve safety and reliability, advanced technology and economical rationality.
(1) Powered by an independent power source of the grid. It requires two independent power supplies from the outside to ensure that the other way can continue to work when one fault occurs. In this way, the capacity and time margin of the power supply are extremely large, and the conversion time is easy to meet the requirements. However, in the case of major disasters, the reliability of power supply may be destroyed and the role of emergency lighting power supply may be lost. Therefore, it is not enough to use this method for emergency lighting power supply for large-scale high-rise buildings and some particularly important buildings. Generally speaking, this kind of power supply is not specially set for emergency lighting. It is often combined with the actual situation of the local power grid and the actual situation of the project (if there is a large amount of primary load) to comprehensively consider the emergency power supply of the power equipment.
(2) Power supply from diesel generator sets. The characteristic is that the power supply capacity and the power supply time are basically not limited, but since the unit is put into operation and takes a long time, the unit that is often in the backup state needs 15s to start from the power failure, so it can only be used as evacuation lighting and standby lighting, but not Used for safety lighting and some alternative lighting for locations where conversion time is critical. This type of power supply is often set up in high-rise buildings to meet fire-fighting requirements, and it is uneconomical to set up emergency lighting.
(3) Use battery power. When the self-contained battery in the lamp is used, that is, the self-contained power emergency lamp has the advantages of high power supply reliability, rapid conversion, convenient increase and decrease, no trouble of line failure, and small influence of battery damage. The disadvantages are that the investment is large, the continuous lighting time is limited by the capacity, and the operation management and maintenance requirements are high. This method is suitable for buildings with few emergency lightings, relatively scattered installations, and small scales; When the battery pack power supply mode is set in a centralized manner, the power supply has high reliability and rapid conversion, and the investment is less than that of the self-contained battery method, and the management and maintenance are convenient. The disadvantage is that special rooms are needed, the battery failure has a large impact, and the line should consider fire protection. This method is suitable for buildings with more types of emergency lighting and larger scales.
(4) Due to the structure of the above several power sources, the degree of reliability is different, and the requirements and application scope of the system are different. Therefore, it is difficult to meet only the requirements of a certain power supply form in actual engineering, and it is difficult to achieve Safe and reliable, economically reasonable. Therefore, the determination of the power supply mode should be combined with the fire power load comprehensive consideration, and two or more types of emergency lighting power sources should be selected at the same time. There are not many emergency lighting lamps. Small-scale buildings use self-contained battery power supply. Large-scale high-rise buildings and some special important buildings are powered by independent power supply of the grid, with generator sets or battery packs, or by power generation. The power supply mode used by the unit in combination with its own battery.
Third, the laying of emergency lighting lines
1. Emergency lighting lines: including distribution trunk lines and branch lines, and common lighting lines must not be co-managed with common slots. Except for the branch line with its own battery fixture.
2. The emergency lighting distribution box should be set separately from the normal lighting distribution box, except for the distribution box with battery lamps, and it is located in a place without fire.
3. The lighting main line of the special grade and the first-class building should adopt the flame-retardant cable, and the emergency lighting branch line should adopt the fire-resistant wire and cable.
4. The distribution line of fire emergency lighting shall be protected by metal pipe. When it is darkly applied, it shall be laid in a non-combustion body with a protective layer greater than 30mm. When it is applied, fire protection measures shall be taken on the outer wall of the protection pipe. For example, when applying acrylic latex fireproof coating on metal pipe and using cable with insulation and sheath as non-flame retardant material, it can be protected without metal pipe, but it should be laid in cable shaft.
5. Emergency lighting should be divided according to fire compartments and must not cross fire zones.
4. Control of emergency lighting
With the increasing number of modern large-scale buildings, the incidence of fire accidents has increased accordingly. At the time of fire inspection, the fire department will require the fire control center to turn on emergency lights and evacuation lights. Therefore, we will focus on the control of emergency lights and evacuation lights during fires. In current electrical design, there are various methods of control, and the common forms are as follows:
One: emergency lighting fixtures are added on the spot, and can be controlled locally. It is suitable for emergency lighting fixtures all using self-contained battery lamps. The power supply is taken from non-fire-fighting power supply. In case of fire, the fire control center cuts off the non-fire-fighting power supply, and the lamps are automatically powered by the battery, so that the purpose of evacuation lighting can be achieved. : Increase the cost.
Second: emergency lighting fixtures do not have switches on the ground, which can be divided into two situations:
a) The distribution box is installed in layers, and the lamps are lit 24 hours a day or night. When the fire occurs, the lights are always bright and do not affect the evacuation of personnel. It is not necessary to be controlled by the fire control center. The disadvantage is: wasting power The lamp life is shortened. î—¤
b) The distribution box is installed in the fire control center. The lighting is turned on and off by the fire control center. Disadvantages: the site cannot be controlled, the use is inconvenient, and for high-rise buildings, the power supply wire is long and the voltage drop is too large to meet the voltage drop of the lamp. The requirements, it is necessary to increase the cross-section of the wire, thereby increasing the cost and construction difficulties.
Three: emergency lighting set switch on the ground, but add a control line, this applies to the case of fire power (dual power), and the emergency light fixtures use ordinary lamps. Usually, the luminaire is directly controlled by the site. When a fire occurs, even if the lamp is turned off, the fire control center supplies power to the intermediate relay KA, and the contact KA is closed, which drives the KM to short the switch, and the luminaire is turned off. If the luminaire is originally turned on, it will not be affected by the closure of the contact KA. This type of solution is the best solution, which is convenient and energy-saving, and can meet the requirements of the specification.
V. Conclusion
In the electrical design of buildings, emergency lighting has received more and more attention because of its unique importance and policy, but how to make emergency lighting design strictly implement national standards and norms, and also need to be in future engineering practice. Further Discussion.
1. Evacuation lighting: Illumination set to ensure that personnel are safely evacuated from the room in the event of an accident when the normal lighting is extinguished due to a power failure. From the point of view of the function, it can be divided into induced indicator lighting and evacuation general lighting. The induction indicator light is used to identify the direction of the safety exit and the location of the safety exit; evacuation of general illumination allows one to see any obstructions on the passage and pass safely. It makes it easy to find manual alarms, call communication devices and fire-fighting equipment along the evacuation route.
2. Safety lighting: Lighting that is set to ensure the safety of potentially dangerous personnel in the event of a malfunction of the normal lighting power supply. Such as the operating room of the hospital, the elevator, and dangerous places such as metallurgical workshops that may cause bruises, burns or falls in the dark.
3. Standby lighting: Illumination set to ensure normal operation or activity continues in the event of a normal lighting power failure.
According to the "High-rise Building Design Fire Protection Code" GB50045-95, its standby lighting should maintain normal illumination. In the "Electrical Design Code for Civil Buildings" JGJ/T16-92 Table 24.7.5, the standby lighting is divided into standby lighting for continued operation and standby lighting for temporary work. The illumination of the former should maintain normal illumination illumination, and the illumination of the latter is quite a lot. 50% of normal illumination. In Article 4.1.3 of the Civil Building Lighting Design Standard GBJ133-90, the standby lighting does not include the illumination of the fire control room, fire pump room, power distribution room and self-supplied generator room, etc., and should not be lower than general lighting. 10%. Different illuminance requirements are specified in each specification. How to meet the illuminance requirements, the illuminance value suitable for the site should be determined according to the different places and their importance and the principle of national standard priority industry standards. For the setting range and setting requirements of emergency lighting, please refer to Table C.1.12 in Appendix C of JGJ/T16-9 of Civil Building Design Code.
Second, emergency lighting power supply system
1. Classification of power supplies
Emergency lighting power can be roughly divided into the following types:
(1) A feeder line from the power grid that is effectively separated from the normal power source. Generally there are:
a. The building has two high-voltage power supplies and two or more transformers. The emergency lighting and normal lighting are connected to different transformers.
b. When the building is powered by only one voltage source, the emergency lighting is obtained by a substation connected from another high-voltage power source.
(2) Self-provided diesel generator sets.
(3) Battery pack: It is divided into the following two cases:
a. The lamp has its own battery, that is, its own power supply emergency light.
b. Battery packs that are concentrated or relatively concentrated, such as EPS, UBS, etc. currently used.
(4) Combined power supply: that is, the power supply mode of any combination of the above two or three power sources.
2. Determination of conversion time
The conversion time is determined according to the relevant regulations;
(1) The conversion time of evacuation lighting should not exceed 15S;
(2) The conversion time of standby lighting should not exceed 15S;  financial commercial trading place ≤ 1.5S
(3) The conversion time of safety lighting should not exceed 0.5S.
The determination of the conversion time is mainly due to the possibility of accidents and economic losses. Some places require shorter conversion times, such as financial business trading venues such as the checkout counter in the mall center, etc. should not be greater than 1.5S. For evacuation and standby lighting, the conversion time is slightly longer and is essentially unrestricted by the power supply. If a diesel generator set is used as the emergency power source, the conversion time can be satisfied by using automatic start and automatic conversion. For safety lighting and some alternative lighting with higher conversion time requirements, because the conversion time is extremely short, it is not possible to directly use the diesel generator set as the emergency power source, nor can use the fluorescent lamp as the power source. The incandescent lamp must be used for instantaneous ignition. Automatic conversion.
3. Determination of continuous lighting time
From the types of emergency lighting power supply and the conversion time requirements, it is not difficult to see that the continuous working hours of emergency lighting are subject to certain conditions. In the "High-rise civil building design fire protection code" GB50045-95 and "Building Design Fire Protection Code"  GBJ16-87 revised version: emergency lighting and evacuation indication signs, the battery can be used as a backup power supply, and the continuous power supply time should not be less than For 20 minutes, the continuous power supply time of high-rise buildings with a height of more than 100m should not be less than 30min. The emergency lighting supply time of the refuge layer should not be less than 1.00h. In the "Electrical Design Code for Civil Buildings" JGJ/T16-92 Appendix C.3.12: Continuous working hours of evacuation indicator lights: high-rise buildings ≥ 30min, super high-rise buildings ≥ 60min, standby lighting continuous working time > 120min; visible The continuous power supply time specified by the two specifications is different. The design should be based on the principle that the industry standard obeys the national standard. For emergency lighting systems connected to the grid or generator sets, the continuous working time is easy to meet the requirements. For battery-powered emergency lighting systems, the working time is limited by the capacity. Therefore, it is not advisable to use the battery pack separately for places requiring long working hours, and it should be considered for use with the generator set. In this case, it is powered by the battery pack and is only used as a backup power source for emergency lighting.
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