Fire Safety Problems Of Civil Buildings And The Corresponding Solutions

Fire safety in civil buildings is getting more and more attention in recent years by society development in China.Along with the introduction of fire protection laws and regulations,such as <Fire Protection Law of the People 's Republic of China>,works on fire safety in civil buildings are started comprehensively.Along with the developments of fire detection and fire safety assessment in recent years,a large number of fire safety problems are exposed.Many common problems are found in fire detection.These problems include that joints or kinks often appears in the cable duct,outdoor fire hydrants and water pump adapters are arranged unreasonably,ground drainage facilities of wet alarm valve are not completely,the residual pressure value is insufficient in smoke staircases and fire front rooms in high-rise building,smoke exhaust value by experimental test is less a lot than the theoretical one,fire door which need be always close cannot be closed automatically,illumination of emergency lighting in equipment rooms is insufficient,fire elevator is arranged unreasonably.It is showed that many hidden dangers which exist in fire facilities in civil buildings nowadays,mainly distributed in fire automatic alarm system,smoke control system and fire door system.Almost every problem in fire protecting system is related with construction process.Design problems exist in water fire extinguishing system and smoke controlling system and equipment product quality problems exist in fire automatic alarm system,smoke control system and fire door system.Solutions are proposed from many aspects of designing,construction,management,equipment quality.A lot of fire safety assessments shows that hidden fire dangers in the using process of buildings are usually caused by unqualified fire safety management.Because of different uses of buildings,industry differences also exist in fire safety management.In particular,problems appeared in colleges include that fire legality file is missed,the function of the room is changed casually and high fire risks are hidden in dormitories.Problems appeared in malls include that the responsibility for fire safety between the landlord and the tenant is unclear,electrical fire prevention and detection is insufficient,fire separation is not set between kitchen and other areas and the evacuation channel width is too small.Problem appeared in hotels is that Decoration materials are lack of flame retardant properties.Problems appeared in public entertainment places include that high fire risks are hidden in evacuations and smoke exhaust system is set incorrectly.It is showed that the quality of fire safety management is better in hotels and worse in malls and public entertainment places.The additional management focus is put forward based on different industry characteristics.Based on found common fire problems,importance of all basic cases for ‘civil building fire causing a lot of loss' is ranked by fault tree analysis and fuzzy mathematics evaluation method which use triangular fuzzy number.It is showed that the importance of those basic cases that causes fire is highest.Fortunately,the appearance frequency of these cases is very low because of the attention of fire departments and companies.Then those basic cases that causes inadequate evacuation ability is also important.Among these cases,inadequate number of safe evacuation identities,piling up sundries next to emergency exit and evacuation channel and the evacuation channel width being too small appear most frequently.In the rest basic cases,the importance of fire protection system and equipment about fire fighting and evacuation is a little high.The importance analysis provides working guide for fire departments and companies so that there are keys to follow in daily fire work and the loss caused by fire can be decreased to the lowest.In recent years,CFD numerical simulation method is used widely on the field of fire and correctly operated smoke control system is the basic guarantee of people's lives when they evacuate.In order to solve two common problems in smoke control system in civil buildings,CFD numerical simulation methods are used to establish a new method for calculating the residual pressure in smoke staircases and fire front rooms in high-rise building.A solution that adding a layer of galvanized steel in the blowhole close to the well wall is proposed to decrease the wall roughness and solve this problem.The feasibility and correctness of this solution is proved by the new CFD method.CFD numerical simulation methods are also used to establish another method for calculating wind velocity of exhaust outlet and pressure loss of the most unfavorable pipe section in smoke exhaust system.By using this method,this article analyzes reasons why smoke exhaust value by experimental test is less a lot than the theoretical one in an actual garage.A new layout method of wind velocity measurement point is proposed to decrease the system deviation for measuring wind velocity and and it is proved that can be used in actual engineering by CFD numerical simulation results and experiment results.Based on the results of fire detection and fire safety assessments of many actual engineerings in ChongQing,the article summarizes the common problems according to the fire system and building functions.Using these common problems as basic cases of ‘civil building fire causing a lot of loss' fault tree,the article analyzes their importance by fault tree analysis and fuzzy mathematics evaluation method and illustrates a macro understanding on the fire safety status of civil buildings.And to smoke control system as an example,the article analyzes the problem that residual pressure in smoke staircases and fire front rooms in pressurized air supply system is insufficient and smoke exhaust value by experimental test is less a lot than the theoretical one in an actual garage.This process helps related personnel understand common fire problems and solve them more specifically and deeply in their actual fire work.