Construction of steel structure fire plan

Construction of steel structure fire plan
First, we have to analyze the characteristics of fire steel construction. Steel construction beams, columns, roof trusses are built skeleton, its security is directly related to the security of the entire building construction, they mostly use the steel, the steel Although non-combustible material, but its fire resistance is poor, with the temperature changes, mechanical target will change substantially, capacity and balance stability with temperature increases significantly. Steel at the temperature reaches 350 ℃, 500 ℃, 600 ℃, its strength parting down 1 / 3,1 / 2,2 / 3, the internal stress of change can also occur under high temperature conditions, so steel bearing system presents problems , according to theoretical calculations, at full load, loss of balance stability steel critical temperature of 500 ℃, fire temperatures are generally about 800 ℃ -1000 ℃, at such a high temperature condition, no maintenance of steel soon will be presented plastically deformed, probably will be destroyed within 15 minutes of collapse. September 11, 2002, New York World Trade Center collapses in terrorist attacks, resulting in more than 300 firefighters innocent lives. After the aircraft loaded with fuel crashing building, causing the building's load-bearing steel cylinder maintenance layer is damaged in the strong temperature effect, steel cylinder bearing strength declined rapidly, just 20 minutes after the world's most famous construction on disappear in our faces. In 2003, China Chia Tai Food Factory steel plant in Qingdao catastrophic fire, resulting in a large area of ​​the plant collapses, many workers buried raw flames; 1972 Tianjin stadium fire, causing the roof to collapse, causing huge casualties. These cases are a large number of fires exposed the steel construction of the existence of a fatal weakness is the poor fire resistance, which gives us the majority of construction planners proposed a new topic, how to do fire planning steel construction, make steel construction to better serve our economic development. Hainan Steel
How can we do fire planning steel construction it? I think that should do the following three aspects:
First, according to fire risk and the importance of the construction material, reasonably determine the construction of fire rating. All kinds of construction due to its use of different functions and importance of fire risk differences, when we plan to build the request according to the owners, according to "construction plan for fire protection" and "planning the construction of high-rise residential fire norms", determined to build things fire risk, according to fire risk, determine the fire resistance rating of construction, such as comprehensive building a 60-meter-high, according to the "high regulation" which belongs to a class of high-rise construction, its fire resistance rating should be level, its beams, column, the fire resistance of roof bearing member should leave no less than two hours, three hours, 1.5 hours, if we do not properly approved fire rating in the planning, determine the fire resistance rating is too high or too low, will cause our planning mistakes, too High wasteful, too low, resulting in insecurity.
Second, planning to choose the appropriate fireproof protection measures. At present, China mainly uses three types of steel maintenance methods: spraying, cladding method, water spray cooling method, they are by some technical means to improve the fire resistance of steel structures. Specifically, the spray coating method that is coated with a layer of fire retardant coating on the steel surface to form a protective film, thereby improving the fire resistance of construction components, it has thick and thin points, different coating thicknesses different fire resistance ; cladding method is the use of brick, concrete, calcium silicate board and other materials will be wrapped in steel, thereby forming protective layer, to improve the fire resistance of members; washout cooling method when automatic sprinkler system is arranged in the upper part of the steel structure, fire, start Spray the steel surface constitutes a continuous film of water to reach the maintenance effect. When we plan, according to the request of members of different fire resistance of construction, scientific comparison, select the most appropriate fire protection measures, reach economic and security requests.
Third, the steel construction planning to fully consider the staff dispersion problems. Since the steel construction of its own weaknesses, we should give full consideration when planning staff dispersion factor, the occupant density target and steel construction features, taken together, to strengthen road safety dispersion, dispersion distance, dispersion width of planning requests, assurance personnel dispersion time is less than the fire resistance of construction components, make sure that when people can safely escape a fire, Qunsiqunshang avoid fire accidents. Hainan Steel