Factors and Countermeasures of the most fire-fight

Factors hindering the use of fire elevators and Countermeasures

China's high-rise building fire prevention Code stipulates that public buildings, industrial buildings and residential buildings with a height of more than 32 meters should be equipped with fire elevators. In case of fire, the current fire elevator is difficult to play its due role, and its safety and reliability are not very high. There are many factors that hinder the reliable use of fire elevators, mainly in the following aspects:

first, factors affecting the reliable use of fire elevators:

(first) fire elevators are vulnerable to fire damage. 1. The fire elevator machine room is generally located on the top of the building. According to the specification requirements, from the perspective of machine room safety, it is required to make an independent fire compartment treatment. However, in fact, due to the existence of cracks caused by cables and air ducts passing through the wall, and the fact that the fire door cannot be kept normally closed, the heart equipment of the elevator is extremely vulnerable to high temperature in case of fire, resulting in paralysis. 2. The hoistway of fire elevator is not set independently according to the specification requirements, but how to upgrade some fire testing machines? The elevator and passenger elevator share the shaft, and there is no effective fire separation between them. Since the passenger elevator has no requirements for the fire front room, it is vulnerable to fire damage, which will affect the "neighbors", resulting in the normal use of the fire elevator. 3. Generally, the cables supplying the power supply of the fire elevator are discharged from the strong current shaft of the building to the top, and then discharged into the elevator machine room through the bridge. Although the use of fire-proof cables has a certain fire resistance capacity, it is difficult to maintain normal power supply permanently in case of building fire

(II) fire elevators are vulnerable to smoke. 1. There is no effective fire separation in the front room of the fire elevator, mainly because the wall of the front room has holes and the fire door cannot be kept closed. 2. The mechanical pressurized air supply system in the front room of the fire elevator failed to work effectively. Generally, there is no natural ventilation and daylighting in the front room of the fire elevator, so it is necessary to use the mechanical pressurized air supply system to prevent the smoke from entering. However, because the fire door of the front room cannot be closed when a fire occurs, the mechanical positive pressure air supply fails, and the eddy current is generated due to the improper setting of the mechanical pressurized air supply outlet, the piston effect of the elevator car, etc., harmful smoke will invade the front room of the fire elevator. 3. There is no effective fire separation between the fire elevator machine room and other elevator machine rooms according to the specification requirements. Because the fire and smoke prevention requirements of non fire elevators are different, and because of the role of the car piston effect, it is very easy to suck smoke into the elevator machine room, and then suck smoke into the fire elevator shaft from the machine room, and enter the fire elevator car. After the completion of the project, personal safety will be endangered

(III) the technology of fire elevator is still difficult to fully ensure its safe use. 1. The fire elevator itself has no waterproof function, which is a worldwide problem. The control panel of the fire elevator has no waterproof function, and all building fires need to use a lot of water to fight the fire. Even if water retaining facilities are set according to the current specifications, it is difficult for the fire elevator to adhere to the use in the process of fire fighting. 2. The control mode of fire elevator has not been unified. Since there is no unified national standard, some fire elevators have special fire start buttons for fire protection, while others can achieve the same function only by opening the special matching keys; After some special buttons are activated, the car will automatically make a forced landing to the first floor door open, the internal buttons can be used by firefighters, and the external floor buttons will automatically fail. However, after some fire elevator special buttons are activated, the fire elevator can still be used normally. The car can still be used as usual without forced landing to the first floor or the external floor, which cannot meet the use requirements of the fire elevator. 3. The fire elevator itself has no reliable safety performance. Most of the currently used fire elevators have no fall prevention function, and there is no emergency exit in the lift car. There are many reasons for the above problems, including standards, technology, design, construction and management. The omission and disconnection of any link will affect the reliable use of the fire elevator

second, several methods to improve the reliability of fire elevators should be improved from the following aspects based on the principle of setting for use and using for reliability

(I) revise and improve the technical standards of fire elevators to improve the reliability of fire elevators. 1. Clarify the technical standards of fire elevators, unify the control procedures, clarify the priority of special fire functions, and uniformly set the special fire start button on the first floor as the fire function transfer switch. 2. On the basis of investigation, the corresponding technical requirements can be put forward for the waterproof problem of fire elevators, so as to gradually develop in the direction of waterproof elevators. 3. Add the function of combining floors when the fire elevator is powered off (the function of automatic door opening and parking of the elevator car on the nearest floor), set the anti falling function by mechanical means, and add an emergency escape exit on the top of the elevator car to ensure that people can safely escape from the car in case of fire elevator failure

(II) adjust the relevant requirements of the current code for fire protection design of buildings, so that the fire elevator can have a safe operation environment. 1. Improve the smoke prevention design of fire elevator. At present, the specification emphasizes that with the further development of the manufacturing and materials industry, the positive pressure air supply in the front room of the ladder is used to increase the air pressure in the front room to prevent the smoke from entering. Due to the setting position of positive pressure air supply outlet and the difficulty of keeping the fire door closed, the actual smoke prevention effect of this method is not necessarily ideal. The effect of air supply and pressurization through the fire elevator shaft may be more ideal, and the effect of preventing smoke from entering the front room and lift car should be more obvious. 2. Strengthen the blocking and drainage capacity of the front room of the fire elevator. Although the specification has requirements for this, it has not been successfully applied in engineering. As fire fighting requires a lot of water, it is very easy to cause water to flow into the elevator and affect the use. Therefore, it should be emphasized that in the front room of the fire elevator, there is a certain drainage slope from the elevator entrance to the door. At the same time, a drainage trough should be added at the elevator entrance to drain the water to the water collecting well through the special drainage pipe in the elevator shaft, so as to effectively prevent the water from entering the fire elevator. 3. Improve the cable laying method of fire elevator. The cable laid in the current way is vulnerable to fire. The fire elevator cable can be directly connected to the elevator machine room from its shaft from the lower power distribution room to reduce the threat of fire to the cable. 4. Appropriately reduce the conditions for building to be equipped with fire elevators. In order to really play a role, the setting requirements of fire elevators are quite high, and cities with relatively concentrated high-rise buildings are equipped with fire climbing vehicles of about 45 meters. In order to reduce the construction cost, it is suggested to adjust the standard of setting fire elevators, and the building height from 32 meters to 45 meters, or even higher

(III) increase the construction quality and operation management of fire elevators. In our work, we often find that fire elevators cannot be used normally due to inadequate construction and management. Therefore, on the one hand, there should be practical and effective standards, on the other hand, we should also increase the construction quality and operation management of fire elevators

(IV) strengthen the training of firefighters' ability to use fire elevators and escape in case of emergency. Due to the different structural forms and fire function operation methods of various fire elevators, it is very necessary to train firefighters in this regard and make up this lesson to ensure that firefighters can escape smoothly in case of emergency and avoid life safety threats. (end)