subject: Large-span steel structure fire hazard and precautionary measures - large span steel structure, fire danger, fire prevention - Fire Industry [print this page] Large-span steel structure fire hazard and precautionary measures - large span steel structure, fire danger, fire prevention - Fire Industry
Large-span steel structure fire hazard and precautionary measures Jinhua detachment / Zheng Weiguo With the deepening of economic restructuring, the rapid development of industrial enterprises, large buildings is increasing. On the one hand because the production process on the other blind business owners seeking large, than the width, resulting in larger volumes, more construction. Steel structure with short construction period; available area, plasticity, seismic, bending, load big advantages to steel as the preferred long-span construction. However, fire-resistant steel as a building material because of its poor performance, easy to collapse of defects in a series of fire prevention work is facing new problems, this paper, the author of the work practice to talk about the large-span steel structure fire hazards and preventive measures:
A large span steel structure of the fire hazard
(1) fire rapid development, easy to form large-scale burning. Large span steel structure, a large space inside the building, doors, windows and more rapid air circulation, internal fire separation is not obvious in case of fire, spread way to more rapid development of fire, burning fiercely, extremely strong convection in the formation of a large area under fire. Large-span steel structure fire hazard exists is part of the main factors of construction projects without the fire of examination and acceptance.
(B) poor fire resistance of steel construction, easy to collapse. Steel material in the un-fire deal with the case, does not in itself a fire; but fire intensity will drop rapidly. It has been tested in full load condition, so that the stability of steel loss of static equilibrium critical temperature is 500 degrees, and general fire temperatures can reach 800-1000 degrees. In such a high temperature, the exposed steel will soon deformation, partial destruction, resulting in the collapse of steel as a whole. Ordinary steel plant is generally about 15 minutes after the fire will lose the load-bearing function and collapse, such as the Jiangnan Development Zone, Jinhua City Feilong Pharmaceutical Co., Ltd. steel warehouse fire, the fire less than 20 minutes after the fire in central heavy steel frame office the collapse occurred.
(C) put out the fire difficult. Large-span steel structure fire, the fire quickly developed into severe stages of the implementation of fire, due to plant large span, coupled with the internal equipment and more complex layout, directly hinder fire-fighting personnel to go to an internal attack, the general Water gun Jet difficult to reach the fire point, fire-fighting agents to use inefficient. And steel structure in fire fighting, the commander of " Collapse "The fear, and that the formation of operational commitment, the choice of offensive line will have an impact. Steel water gun fire in the fighting when the jet as the impact of cooling effect of the steel structure to collapse bending strength decreases, causing fire embers clean-up difficulties, fire fighting more difficult and the workload increases. Slump curved steel structure due to large volume and weight, clean up when large-scale mechanical work, to some extent also reduced fire Accident The progress of the investigation.
Second, there is a large span steel structure factors of fire risk
(A) part of the construction project without the fire of examination and acceptance. Some items not considered in the design of fire protection, construction process, failure to plan construction, after completion of the project without a fire inspection, allow for the checking of several links are ignored. As the owner of the fire safety consciousness, together with local governments in the process of re-introduction of capital investment to how much light procedures, tacit business built without trial, without first testing the illegal use of the phenomenon, and put into use in the steel construction is finds it difficult to fire prevention.
(B) the owner change the use without authorization function, increase the fire danger. Part of the steel plant fire review and acceptance of the declaration when the fire danger is small E, which may actually be a Class C plant, or put into use initially D E production, and later adjusted due to production projects are not promptly reported, such as Jinhua City Feilong Pharmaceutical Co., Ltd. is a small warehouse in the approval of E when in fact a large number of warehouses piled combustible inflammable materials; plant due to the need for thermal insulation, steel tile roof, ceiling, partition set flammable insulation materials, artificial lower fire rating. Another trend should be cause for concern, the economic interests of the Design Institute for intentional circle, or set a cap so you drill, so we can not blindly believe that since the examination table, because the fire department of the institute for processing no precedent.
