非承重木骨架组合外墙火灾蔓延研究

发布时间：2018-08-13 16:36

【摘要】：目前非承重木骨架组合墙体在国内使用的不多,处于推广与发展阶段。针对其火灾方面的性能研究较少,一般仅限于耐火极限研究,通常设置一定厚度的防火石膏板即可达到耐火极限要求。而从窗洞口喷出火焰在外墙上的蔓延相对比较复杂,这也是建筑发生火灾蔓延的主要形式之一,因而本文主要针对火灾在木骨架组合外墙竖向蔓延进行了研究。本文主要通过FDS数值模拟火灾在木骨架组合外墙上的蔓延,通过小型火灾试验和软件模拟进行对比分析,从而验证了FDS对于本文火灾模拟研究的的适用性和可行性。采用FDS对非承重木骨架组合外墙进行了火灾模拟研究,通过设置不同的防火挑檐、窗槛墙、窗洞口、风速和不同维护构造来研究火灾在在组合外墙上的竖向蔓延,与此同时还将窗洞口喷火与门洞口喷火在组合外墙上的蔓延进行了分析与比较,总结出以下结论:(1)相比于位置和厚度,防火挑檐的宽度对于火灾在组合外墙上的蔓延影响最大,当宽度从无增加到500mm时,效果已经很明显。(2)窗槛墙虽可以阻碍火灾在组合外墙竖向蔓延,但是随着窗槛墙高度的增加,效果越来越不明显,故在条件有限时,可考虑将窗槛墙和防火挑檐结合起来阻隔火灾在组合外墙上竖向蔓延。(3)窗洞口宽度增加促进火灾在组合墙体上的蔓延,高度增加则减缓火灾蔓延,故设计窗洞口尺寸时,尽量避免宽高比过大;此外窗洞口位置越低,喷出火焰和烟气对组合外墙影响越大,故建议窗洞口的位置尽量选择房间相对较高的位置。(4)风对火灾在组合外墙的竖向蔓延影响比较复杂,本文仅考虑风垂直墙面,随着风速的增加,火灾在组合外墙温度逐渐升高,但是影响逐渐变小。(5)当室内发生火灾时,与门洞口相比,从窗洞口喷出的火焰和烟气对组合外墙产生影响较大,而从门洞口喷出的火焰对相邻的建筑物会产生较大影响。(6)通过外挂石膏板与木挂板进行火灾模拟研究,得出木挂板加速了火灾在组合外墙上的蔓延,当外挂板材料燃烧热释放率增加时组合外墙温度随之增加。故设置外挂板时,必须使用耐火等级高或经过特殊防火处理的材料。
[Abstract]:At present, non-load-bearing wood skeleton composite wall is not used much in our country, and it is in the stage of popularization and development. In view of its fire performance research is less, generally limited to the study of fire resistance limit, usually set a certain thickness of anti-fire gypsum board can meet the fire limit requirements. The spread of flame from the window hole on the exterior wall is relatively complex, which is also one of the main forms of fire spread in the building, so this paper mainly focuses on the vertical spread of the fire in the wood skeleton composite external wall. In this paper, the spread of fire on the wood skeleton composite exterior wall is simulated by FDS numerical simulation, and the feasibility and applicability of FDS for the fire simulation are verified by comparing and analyzing the small scale fire test and software simulation. The fire simulation of non-load-bearing wood skeleton composite exterior wall was carried out by using FDS. The vertical spread of fire on the composite exterior wall was studied by setting different fire prevention eaves, window sill walls, window openings, wind speeds and different maintenance structures. At the same time, the paper analyzes and compares the spread of the fire from the window hole and the door hole on the combined exterior wall, and concludes the following conclusions: (1) compared with the location and thickness, the width of the fire-proof eaves has the greatest influence on the fire spread on the combined exterior wall. When the width is increased from zero to 500mm, the effect is obvious. (2) although the fire can be prevented from spreading vertically in the composite wall, the effect becomes less and less obvious with the increase of the height of the sill wall, so when the condition is limited, The combination of sill wall and fire-proof eaves can be considered to prevent the fire from spreading vertically on the composite wall. (3) the increase of the width of the window opening promotes the spread of the fire on the composite wall, and the increase of the height will slow down the fire spread, so when the size of the window hole is designed, In addition, the lower the opening position of the window, the greater the impact of the flame and smoke on the combined exterior wall. Therefore, it is suggested that the location of the window entrance should be as high as possible. (4) the influence of wind on the vertical spread of the fire on the combined exterior wall is more complicated. In this paper, only the vertical wind wall is considered, with the increase of the wind speed, the fire temperature increases gradually in the combined exterior wall. But the influence becomes smaller gradually. (5) when there is a fire in the room, compared with the entrance of the door, the flame and smoke from the window hole have a greater impact on the combined exterior wall. However, the flame ejected from the entrance of the door will have a great impact on the adjacent buildings. (6) through the fire simulation study of plasterboard and wood hanging board, it is concluded that the wood hanging board accelerates the spread of fire on the combined exterior wall. When the combustion heat release rate of the external panel material increases, the temperature of the combined exterior wall increases. Therefore, when setting external boards, must use high fire-resistance or through special fire-resistant materials.
【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU998.1

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