大空间火下膨胀型防火涂层隔热性能试验研究

Experimental Study on Fire Protection Performance of Intumescent Coating Under Large Space Fires

对应3种不同类型的大空间建筑火灾场景,选取3种典型升温条件进行36个试件的隔热性能试验。根据试验测量结果计算膨胀型钢结构防火涂层的等效导热系数,研究大空间火下涂层的膨胀特点及隔热性能,结合热重分析试验结果考察升温速率对涂层隔热性能的影响。结果表明:不同类型大空间建筑发生火灾时火场的最高温度及升温速率不同,导致涂层的膨胀倍率及炭化层泡孔结构不同,最终表现为涂层隔热性能的差异。在作者所考察范围内,升温速率越快,火场温度越高,涂层的反应越充分,隔热性能越好。不同升温条件下涂层等效导热系数代表值$min的最大差异为48.8%。此外,膨胀型钢结构防火涂层等效导热系数随升温条件的变化程度受涂层厚度的影响,薄涂层对升温条件的变化敏感,厚涂层对升温条件的变化表现出"惰性"。

36 specimens were tested under three different heating conditions corresponding to three different kinds of large space fires. Effective thermal conductivities of intumescent coatings were calculated based on the test measurements. TGA tests were conducted to investigate the effect of heating rate on fire performance of intumescent coating. The study found that the maximum temperature and heating rate were different Under different heating conditions of large space fire, which resulted in different expansion rate and inner structure of intumescent char. The consequence of this is the different insulating properties of intumescent coating under different heating conditions. Increasing the heating rate and the temperature resulted in better insulating properties of intumescent coating. The maximum difference of 48.8% for γmin Was obtained when the coatings were exposed to different heating conditions. In addition,the variation degree of effective thermal conductivities of intumescent coating under different heating conditions was affected by coating thickness, thin coating is more sensitive to the change of heating conditions.