| Yunnan Province is a large province with strong historical and cultural background.There are many ancient wooden structures with historical and cultural background,and there are also many contemporary wooden structures.In China,a large number of traditional wood structure buildings in towns are facing severe fire situation,but the research on the fire protection performance of wood structure buildings is few,and there is no relevant basis.Most of the wooden structure buildings do not meet the safety fire protection standards.At the same time,the traditional town wooden structure building will not be renewable after fire,which will cause serious cultural and economic losses.Therefore,it is of great significance to study the fire resistance of traditional wood structure buildings in towns.This paper takes traditional wooden structure residential buildings in Yunnan Province as the research object,and uses FDS software to simulate the process of fire damage and smoke spread.The main research contents are as follows.(1)Taking a wooden structure building in Lijiang as the research object,the paper uses FDS software to simulate the fire development process and compares with the relevant test data.At the same time,the influence of reference temperature and reaction heat on the numerical simulation results is discussed,and the reasonable values of reference temperature and reaction heat are determined.(2)Taking typical wood structure building as the research object,the fire resistance of the building is studied by FDS software.The influence of opening and closing state of stairway,closing of hanging mountain entrance and fire load on the heat release rate and the development process of indoor fire are explored.In view of the thermal radiation effect of evacuation door on left building,the safe fire distance between the fire building and the left building is determined.According to the results of numerical simulation,the following conclusions are put forward.(1)Through the comparison and analysis of the numerical simulation results and test data,the real development and spread of fire can be simulated by software by setting the material and parameters of the software.The pyrolysis parameters of wood closest to the test data are obtained,namely,the reaction heat is 6000 kj /kg,and the reference temperature is 150 ℃.(2)When the stairway is open and closed,the time taken for the temperature of the second floor to reach the peak value is 800 s faster than the latter;The peak temperature of the second layer is 200 ℃ higher than that of the latter;The peak values of heat release rate are55 MW and 42 m W respectively,and the time difference when the heat release rate reaches the peak is about 1000 s.(3)When the entrance of the two sides of the mountain is closed,the fire risk increases in the early stage of the fire due to the accumulation of heat.But the maximum heat release rate of the whole combustion process is 50 MW,which is about 5% lower than that of the opening of the suspension mountain opening,the maximum temperature of the roof is 850 ℃,and the decrease is about 10.5% compared with the opening of the opening of the suspension mountain opening.In case of fire,it is most effective to put out fire in the primary stage of fire development,so the closure of the entrance of Mount hung has a negative impact on the spread of indoor fire.However,in general,it will reduce the risk of fire spread to adjacent buildings.(4)When the fire load increases by 10%,the time for the heat release rate to reach the peak is almost the same,but the peak value of the heat release rate increases with the increase.The peak value of the heat release rate is 69 mw,which is 20% higher than that of the fire load.The time to reach detonation is 720 s and 610 s,which is shortened by 12%.(5)According to the thermal radiation effect of the building after fire,the safe fire distance between the fire building and the left adjacent building is determined to be 4.8m. |
