Keywords: fire safety; High-rise building; Fire prevention; Put out fires to save lives and property.
China Library Classification Number: TU998. 1 Document Identification Number: A.
1 fire hazard of high-rise buildings
In addition to the typical characteristics of general building fires, high-rise building fires also have the following characteristics:
1. 1 The fire was fierce and spread very quickly.
1. 1. 1 formed a three-dimensional firepower.
Elevator shafts, stairwells, air ducts, pipe shafts and cable shafts in high-rise buildings are prone to form stack effect in case of fire. The experiment shows that the smoke diffusion velocity caused by horizontal air convection is 0.3 m/s in the early stage of fire. The diffusion speed of flue gas along stairwells or other vertical tube wells is 3 ~ 4m/s. For example, in a 30-story high-rise building, flue gas can spread to the top floor along vertical tube wells in about half a minute without hindrance.
1. 1.2 There are many combustible materials for decoration.
High-rise buildings are decorated according to their own characteristics and are luxuriously decorated. There are a lot of combustible substances in the room, especially chemicals, such as furniture, curtains, carpets, ceiling decorations, etc., which will burn violently in case of fire. These chemical raw materials are mainly composed of hydrocarbons, which will produce a lot of toxic gases, as well as a lot of smoke and water vapor, which will do harm to human body, seriously affect the safe evacuation and fire fighting of people in buildings, and easily lead to the spread and expansion of fires.
1. 1.3 pipelines crisscross.
The air conditioning pipes, smoke exhaust pipes, exhaust pipes and cable pipes installed in high-rise buildings are complicated, both horizontally and vertically, which are important paths for the development and spread of smoke fires.
1.2 evacuation difficulty
It is difficult to evacuate the crowd. There are many floors in high-rise buildings, and the vertical evacuation distance is long, so the time required for evacuation to outdoor ground, roof helipad or refuge floor also increases accordingly. Due to the large number of personnel in high-rise buildings and the relatively concentrated personnel in public stadiums, it is more difficult to evacuate in case of fire, and it is easy to cause heavy casualties. When a fire breaks out in a high-rise building, the communication is often out of control, and there is often a fire in the lower floor, but the upper floor is still unknown. Especially in high-rise hotels, there are many people and strangers, which makes it more difficult to evacuate safely and more likely to lead to serious accidents.
1.3 fire fighting is more complicated.
The fire protection design of high-rise buildings is based on "self-rescue", and its fire protection equipment is complex and highly automated. As long as there is a problem in any link, the fire control facilities will not be able to play their full role. It is very important to put out the initial fire, but the field personnel will not use or use fire-fighting equipment. Firefighters arrive at the scene from the station and board the tall building armed to the teeth, which not only consumes a lot of physical strength, but also is inconvenient to contact with the fire center and the water pump room, and it is difficult to cooperate. The building is windy and the fire is fierce. It is much more difficult for firefighters to work under high heat and thick smoke than ordinary fires. At present, the domestic climbing fire trucks can not meet the needs of safe evacuation and fire fighting in high-rise buildings, and can not evacuate outdoor personnel in time.
2 high-rise building fire safety measures and countermeasures
2. 1 Fire prevention measures for high-rise buildings
2. 1. 1 should have sufficient technical support.
High-rise buildings must be equipped with fixed systems such as automatic sprinkler system, indoor fire hydrant system and smoke exhaust system. At the same time, in high-rise buildings, it is necessary to solve the problem of two-way power supply, implement fire partition and fire separation, and set up fire detection system, fire emergency broadcasting system and positive pressure air supply system for evacuation passages. In addition, it should also have information feedback and manual or linkage functions. When necessary, it is necessary to set up a refuge floor or shelter, and set up a helipad on the roof. It is necessary to implement the mandatory provisions related to fire protection in high standards and the fire protection requirements stipulated by special industries such as hospitals.
2. 1.2 should have perfect preventive facilities.
The fire control facilities of high-rise buildings must be complete, perfect, reliable and effective. First, the fire department must put forward rectification opinions in time and instruct the unit to eliminate all kinds of fire hazards in time. Second, the unit should have a sense of fire urgency, increase investment and rectify hidden dangers in time. It is necessary to strengthen the maintenance, inspection and maintenance of fire control facilities and improve the performance of the overall system of fire control facilities. Third, the fire department should test all high-rise buildings to ensure that wireless communication signals can be successfully transmitted to all floors during fire fighting and rescue, to prevent high-rise buildings, especially high-rise buildings with steel structures, from interfering with the communication system at the fire scene and to ensure smooth information. According to the needs of fire fighting in high-rise buildings, users of high-rise buildings should establish wireless or wired automatic alarm networks with the public security fire command center to facilitate the rapid dispatch of rescue forces in case of fire [4].
2.2 High-rise building fire protection measures
2.2. 1 reconnaissance should be fast, accurate, coordinated and unified.
High-rise building fire is seriously affected by smoke, high temperature, strong heat and strong pressure, and it is difficult to detect the fire, so it is difficult to grasp the fire location and fire information at one time. On the basis of strengthening the fire detection power, the first fire brigade can only determine the fire location through the reasonable division of labor and mutual cooperation of fire detectors (groups) and the comprehensive fire information obtained from different angles and directions, thus overcoming human errors and mistakes in the reconnaissance process.
2.2.2 Fire fighting actions should be rapid, orderly and coordinated.
Entering the fire and putting out the fire will buy time for fighting and controlling the fire. Green space, fountains, parking lots and service areas around high-rise buildings will seriously hinder the approach and operation of large secret service vehicles, especially mountaineering vehicles and ladder trucks; Distorted building components, doors and windows, collapsed stairs, roofs and partition walls in the fire floor prevent combatants from entering the fire site and limit the working place of combatants; The continuous combat of combatants, the shortage of fire fighting equipment and the intermittent supply of personal protective equipment have weakened the overall combat effectiveness of the troops. The existence of these factors in high-rise building fires will delay the fire fighting and be beneficial to the firefighters. Only through the mutual cooperation between the fire officers and soldiers and the fire brigade can seemingly independent fire fighting actions such as personnel and materials evacuation, fire site demolition, fire site equipment and combatant supply be organically combined and overlapped in the fire fighting process, thus shortening the emergency rescue and fire fighting time and reducing various additional losses.
2.2.3 Logistics supply should be strong.
The logistics supply of the fire site is mainly to dispatch firefighters, transport fire fighting equipment and enrich and replace personal protective equipment. It is not only required to deliver enough quantity to the fire site in time, but also to ensure the replacement of various equipment, such as the replacement of air respirator steel cylinders and the supply of standby power. Poor or insufficient fire fighting equipment will weaken the fighting capacity of emergency rescue and fire fighting to a certain extent. In addition, the fire-fighting equipment in high-rise building fire must also be transported to the centralized point of standby equipment. Inside the building, the concentration point of personnel and equipment should be located on the floor as close as possible to the fire floor, so as to call in time; Outdoor, fire fighting vehicles and equipment should be set in relatively spacious places, but should be close to burning buildings.
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To sum up, because of its unique structural characteristics and functions, as well as management and investment, high-rise buildings have buried congenital and acquired fire hazards. From the above analysis, we can draw the following conclusions:
High-rise and super-high-rise buildings in cities are the inevitable product and general trend of urban and economic development, and fire has become the deadly "killer" of high-rise and super-high-rise buildings, that is, "skyscrapers". Fire protection of high-rise buildings has become a worldwide realistic problem, and modern high-rise buildings have become the "soft rib" of urban fire protection.
Different from other fires, high-rise buildings have the characteristics of rapid fire, rapid spread, difficult evacuation, heavy casualties, poor fire resistance of steel structures, and great difficulty in fire fighting and rescue. Once a fire breaks out, it is difficult to control. The fire prevention of high-rise buildings must follow the principle of "prevention first, combining prevention with elimination".
To prevent and eliminate fire from the source, we must improve architectural design, strengthen fire management, improve and update fire-fighting facilities, and adopt flame-retardant building decoration materials to eliminate fire hazards.
When a fire breaks out in a high-rise building, we must take "self-help and mutual rescue" as the premise, get out of the misunderstanding through the accumulation of fire-fighting knowledge at ordinary times, escape calmly and wisely, and reduce casualties.
refer to
[1] Zhu Jie, Huo Ran, Fu Yongsheng. Study on fire smoke exhaust in super high-rise buildings [J]. Fire Science and Technology, 2007,26 (1): 54-56.
[2] Li, Ren,. Study on fire fighting and safe escape strategy of urban high-rise buildings [J].
[3] Cold runner-up, factors affecting fire safety evacuation of high-rise civil buildings and countermeasures [J]. Building Fire Protection Design, 2003(2).
Zong Xinzhou. Fire rescue of high-rise buildings has become a worldwide problem [J]. China Newsweek, 20 10.
[5] Liu Fang, performance-based design of building fire protection [M]. Chongqing: Chongqing University Press, 2007.