窗口火作用下建筑幕墙外保温系统防火性能的试验

建筑幕墙外保温系统火灾事故发生频率高,火灾危险性大,其防火安全性能已成为社会关注的焦点。采用大尺度实体火试验方法,选取具有代表性的金属幕墙保温系统和保温装饰板外保温系统作为试验对象,对防火隔离带和防火封堵位于墙体不同位置的4种工况,开展了一系列窗口火试验。通过采集试验表观现象、火焰蔓延特性、温度分布特性、系统损坏特征等耐火性能试验数据,综合比较分析了不同工况下不同燃烧性能等级的建筑幕墙外保温系统的耐火性能。结果表明,建筑幕墙上下贯通的空腔结构加剧了火蔓延的烟囱效应,存在较大的安全隐患。防火封堵可以阻断空腔中的热对流,防火隔离带可以阻隔材料之间的热传导,二者均可以有效抑制火焰在垂直和水平方向上的蔓延,大幅提高建筑幕墙外保温系统的防火性能。在建筑外墙窗口上方、水平线1及水平线2下方20 mm处分别设置宽度为100 mm的防火封堵和宽度为300 mm的防火隔离带时,系统具有较好的防火性能,综合考虑实际工程的应用性和经济性,可将其设为防火构造设计的基准参数。

Fire resistance of external thermal insulation systems with curtain on the fire resistance of the external thermal insulation system with curtain wall under the impact of the window spill plume

This paper is aimed at making an experimental study on the fire resistance power of the external thermos insulation system by means of a curtain wall under the impact of the window spill plume method in case of a real serious fire accident.As is known,the external wall insulation systems to be used for the buildiing facade are prone to a high frequency of fire accidents and fire risks,which makes it an urgent social need to study the fireresistance and safety necessities.For the said research purpose,we have chosen a typical metal curtain wall insulation system and the external thermal insulation system based on an insulated decorative panel as a testing object through a series of window fire tests under the four kinds of working conditions with the fire-barrier belt and the fire blocking wall arranged at the different points of the wall.In proceeding with our research,we have analyzed the different combustion features of the fire-resistant external wall insulation system to be used for the building facade under the different fire working conditions through a comprehensive comparison by collecting the noticeable testing phenomena,the flame spreading features,the temperature distributions,the system damage and other fire-resistant behaviors through the experimental data.The results of the analysis of the experimental data and the testing features show that the cavity structure penetration into the building curtain wall tends to aggravate the chimney functions which may result in some potential safety hazards.However,well-done fire-proof sealing can prevent heat convection in the cavity whereas the fire-barrier belt can help to cut off the heat conduction through the materials.Both of the above mentioned measures,if well done,can effectively restrain the spread of the flame in the vertical and horizontal direction and substantially improve the fireproof capability of the external wall thermal insulation system.Thus,it would be possible for the systems to have fine fire-resistant performance if they are built with 100 mm width of the systems and fire-barrier belt with 300 mm width at the top of the building external window with a 20 mm width below Level 1 and Level 2.Taking practical application and engineering economy into comprehensive account,the above said systems we have developed are expected to be as the basic reference to the fire-resistant system construction design.