Study On Smoke Control And Evacuation Of Atrium Commercial Buildings

With the development of economy,the atrium can be seen everywhere in China’s urban buildings due to its strong visual impact and beauty,but it also poses a huge challenge for fire prevention.Due to the difficulty in effective fire prevention and smoke separation,once the fire occurs,the smoke will spread rapidly,the fire will spread quickly,and the internal flow density will be larger,it will cause disastrous consequences.At present,although China has formulated the regulations on smoke prevention and evacuation of atrium buildings,it still needs to be further improved.Therefore,in-depth research on the smoke spreading law of atrium buildings and the influencing factors of personnel evacuation is of great significance for the fire risk control of this type of buildings and the effective organization of personnel safety evacuation.In this paper,a 3D simplified model is established for a large atrium mall.Numerical simulation test method is adopted to study the smoke spreading law of the most dangerous top floor corridor in the case of fire in the atrium building,and the evacuation process is simulated to analyze the factors affecting the safe evacuation of personnel.The smoke spread and evacuation were combined to evaluate the fire risk of the atrium building.The research contents and conclusions of this paper mainly include the following aspects.(1)The influencing factors of flue gas flow were analyzed from the aspects of fire source floor,fire source location,fire source power,smoke emission from surrounding places and smoke emission from corridors.It is found that the smoke spreading law is different in different floors and different positions.When the fire source is located in the middle of the atrium on the first floor,the smoke spreads the most widely and has the greatest influence on the corridor on the top floor.The greater the power of the fire source,the greater the influence on the top floor corridor and atrium,and the greater the danger.When the smoke discharge quantity of the surrounding places is 90m~3/(h·m~2),the smoke control effect in the top floor corridor and atrium is the best,which can greatly extend the available safe evacuation time of personnel.The smoke emission in the corridor has a certain effect on the control of the spread of the smoke in the corridor,but the smoke emission should be set to 60m~3/(h·m~2),the smoke control effect is not significant with the increase of the smoke emission.(2)Visibility is the most important factor restricting the safe evacuation of people in shopping malls.(3)From the number of evacuation,the width of the exit,number and evacuation way aspects analyzes the influence factors of the safety evacuation,the study found that 2～5layers of evacuation efficiency will be increased with the increase of stairwells exit width increase,but the layers of evacuation efficiency will reduce with the increase of floor,for more than 6 layer and personnel evacuation without help;The reduction of the number of safety exits will lead to a significant increase in the evacuation time of the personnel on each floor,among which the evacuation of the top-level personnel is the most unfavorable.The higher the number of evacuees on each floor,the longer the evacuation time.The evacuation efficiency of the top floor is the most sensitive to the change of the number of evacuees.Hierarchical evacuation can improve the evacuation efficiency of the top layer and reduce the time of the personnel exposed to the high-temperature smoke.(4)The available safe evacuation time obtained by fire simulation test is compared with the necessary safe evacuation time obtained by personnel evacuation simulation.When the smoke emission amount of the surrounding places is set to 90m~3/(h·m~2),the safe evacuation of personnel can be guaranteed to the maximum extent.