Emergency lighting for civil buildings

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.

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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