"All-in-one" In The Urban-rural Fringe Based On Numerical Simulation Research On Building Fire Risk Assessment

"All-in-one" building fire accidents occur frequently in the urban-rural fringe,causing huge losses.Effective prevention and control of "all-in-one" building fire accidents in the urban-rural fringe is of great significance and practical urgency to the safety of local residents’ lives and property and social stability.The most fundamental purpose of fire risk assessment and control is to minimize casualties and property losses in fire.This article analyzes the research results of many domestic and foreign researchers on "all-in-one" building fires and personnel safety evacuation in the urban-rural fringe.Refer to the relevant theories of fire risk assessment,fire spread simulation and personnel safety evacuation simulation,this paper proposes to use the fire risk assessment method to draw the assessment conclusion,and then use numerical simulation to further determine the safety of the area where the "all-in-one" building is located.Finally,the "all-in-one" area and buildings in the urban-rural fringe are proposed.Corresponding prevention and control countermeasures.Specific research contents and methods are as follows:1)This paper combines fault tree,analytic hierarchy process and fuzzy comprehensive evaluation to analyze the fire risk situation of an "all-in-one" building.The evaluation index system of 6 first-level indexes,including building’s own condition,fire occurrence factors,fire fighting facilities,fire fighting ability,safety evacuation system and fire safety management,and 26 second-level indexes is established.Through calculation,the safety level of the "all-in-one" building is relatively safe,and the weight value of fire safety evacuation is0.3312,which is the most important factor affecting the fire risk of the "all-in-one" building.2)According to the conclusion of fire risk assessment,the method of computer numerical simulation is selected.The fire simulation software Pyro Sim is used to simulate and analyze the three possible fire scenarios of the "all-in-one" building-warehouse,right bedroom on the second floor and business area,and to determine the time when the only evacuation exit and the temperature,CO concentration and visibility of each floor reach discomfort under these three fire scenarios.The three scenes are 180s;180s;275s.After,the evacuation simulation software Pathfinder was used to simulate the evacuation of people in the building to obtain the required safe evacuation time for all people to evacuate,172.56 s.3)In order to quantify the fire safety of the "all-in-one" building,from the perspective of reducing casualties,redundant evacuation time is introduced,that is,the ratio of evacuation time to necessary evacuation time.It is concluded that the redundant evacuation time of the warehouse is 1.0547,the redundant evacuation time of the right bedroom is 1.2170,and the redundant evacuation time of the business area is 1.5963.The corresponding safety is relatively safe,safe and safe.Therefore,the comprehensive safety of the buildings in the "all-in-one" area is evaluated as relatively safe,and the corresponding prevention and control measures are put forward.