Discussion on fire safety of the hottest building

Discussion on building fire safety issues

the Hengyang fire, which caused a nationwide sensation, caused the heroic sacrifice of 20 firefighters. On February 15th, 2004, a fire broke out in Wufeng village, huangwan Town, Haining City, Zhejiang Province, causing 40 deaths and 3 injuries; On the same day, a fire broke out in Zhongbai commercial building in Jilin City, Jilin Province, killing 53 people and injuring 70. The frequent occurrence of building fires has claimed many lives and caused huge property losses. Therefore, it is necessary to discuss the safety of building fire to reduce the loss of life and property caused by fire. Based on many years of construction engineering supervision practice, the author talks about his preliminary views from the aspects of building fire prevention design, fire fighting officers and soldiers and the self rescue of the masses in case of fire

1 problems that should be paid attention to in building fire protection design

in order to avoid and reduce the harm of fire to buildings, in addition to meeting the code for fire protection design of buildings and code for fire protection design of high rise civil buildings and the special fire protection requirements of various buildings, according to the different characteristics of buildings, Attention should also be paid to the following issues:

1.1 design of reinforced concrete components

the fire resistance limit of reinforced concrete columns, beams and slabs is very important, especially columns. In case of fire, once there is a problem, the building will collapse in a very short time. The author observed the buildings with many fires and found that the synchronous belt and reducer of reinforced concrete components were separated from the reinforcement after the fire, and some of them had fallen off. After analysis, it was believed that the reason for this phenomenon was related to the thickness of the protective layer of the reinforcement. The thinner the protective layer, the worse the fire resistance performance. At present, the minimum thickness of the protective layer of reinforcement required by the code is to protect the reinforcement from corrosion, without considering the impact of high temperature on the reinforcement after a fire. In order to avoid excessive deformation of reinforcement in case of fire and reduce the bonding force between reinforcement and concrete, the thickness of the protective layer of reinforcement should be appropriately increased in the design; Especially for the protective layer of prestressed reinforced concrete components, the minimum thickness specified in the code is smaller than that of ordinary concrete components, so the fire resistance performance is even worse. Protective measures such as increasing the thickness of the protective layer of reinforcement or plastering the lower surface after hoisting must be taken to improve the fire resistance limit and meet the requirements of fire safety. In addition, the section size of the member also has a great impact on the fire resistance performance. For the sake of safety, the section size of the column at the bottom and important parts should be appropriately increased

1.2 among them, the import from Malaysia increased by 529.76% year-on-year. In the quality supervision work, the author saw that some steel members did not require fire prevention treatment in the design. We know that the fire resistance of the boiler components is very poor. Under high temperature, the strength and bearing capacity of the steel components decline particularly fast. In order to ensure the strength and bearing capacity of the components before the fire, the design should require that the thermal insulation fire protection layer be pasted or painted on the surface of the components to improve the fire resistance limit of the steel components

1.3 design of special components

for cantilevered components and components that are easy to lose stability, combustible materials cannot be used to maintain balance, so as to prevent the occurrence of fire, that is, through its speed difference to achieve the transmission of appropriate power. After the combustion of combustible materials, the components collapse. For example, the warehouse of Meihekou hardware station is a single-layer brick and wood structure, with a span of 10m, a length of 60m, and a cornice height of 4.5m. It is equipped with six gates, with a door width of 4m. Each gate has a canopy board with a length of 1.2m and a width of 4.5m. The safety check elbow of the canopy overturning is designed to test the overturning moment generated by the wooden roof frame pressed on the canopy beam, so the check calculation is no problem under normal use conditions; But in March, 2000, a fire broke out in the warehouse, and the fire spread to the wooden roof frame. Because the cornice of the warehouse was high, the firefighters stood on the ground and used water guns to put out the fire. They found the picked awning board, so four firefighters climbed on one awning board successively, some were uncovering tiles, and some used water guns to shoot water at the roof frame. Just as they were concentrating on the fire, the wooden roof frame pressed on the awning beam was burned out, The roof truss collapsed, and then the canopy overturned. Before the four firefighters reacted, they fell with the canopy and were pressed under the canopy, making a heroic sacrifice on the spot

1.4 design of comprehensive building

in recent years, there are many buildings with commercial buildings on the ground floor and residential buildings on the upper part. Because commercial buildings consume large amounts of electricity, have many kinds of goods, and are basically flammable crystals. Such as careless use of electricity and smoking, these rooms will cause fire. In order to prevent the impact of a fire in a commercial building on the upper residence, fire barriers should be set up between the commercial building and the residence in the design, and there should be separate staircases. After sale, there should be no need to say the entrance. They should be completely separated, so that the flow of people and the flow of goods can be separated into two channels without interference with each other

in addition, the commercial houses on the ground floor generally have large doors and windows. In order to prevent the fire from entering the upper window from the door and window outdoors after the fire, cornices, sunshades, balconies, awnings or veranda should be set on the upper part of the larger door and window in the design, so that the upward flame is blocked and deviated outward, away from the upper window, so as to achieve the purpose of fire prevention

1.5 design of special rooms

for some rooms that are not easy to drain after ponding, drainage holes shall be set at appropriate parts. In case of fire, the fire fighting water can be discharged smoothly, reducing the load weight of the floor. Balconies to be avoided are set in some parts to avoid the threat of smoke and fire for people who have no time to evacuate. They can also be used as positions for firefighters and water gunners