| 摘要: |
| 对水溶性(W型)和溶剂型(S型)这2种膨胀型钢结构防火涂层在ISO 834标准火及3条非标准火升温曲线下的隔热性能进行了试验研究,其中3条非标准火曲线的升温速率及最高温度均低于标准火.试验结束后对不同升温机制下防火涂层的膨胀倍率和膨胀层的泡孔结构进行定性对比分析,并根据隔热性能试验中温度的测量结果计算防火涂层的等效导热系数,用以对不同升温机制下防火涂层的隔热性能进行定量分析.分析结果表明: 升温速率影响膨胀固化阶段气体的逸出率,进而对防火涂层的膨胀倍率产生影响;升温速率不同,发泡剂分解释放气体的时间与熔融态涂层黏滞性的匹配度不同,炭层的泡孔尺寸不同;膨胀倍率越大,泡孔尺寸越小,炭层的隔热性能越好;与标准火下防火涂层的等效导热系数相比,非标准火下防火涂层的等效导热系数均有不同程度的提高,最大差异为65%(W型)和35%(S型);用标准火下膨胀型防火涂层隔热性能的检测结果来指导非标准火(火场温度和升温速率均比标准火低)下防火涂层的设计将导致不安全的结果. |
| 关键词: 膨胀型防火涂层 升温机制 膨胀倍率 泡孔尺寸 等效导热系数 |
| DOI：103969/j.issn.1007 9629201901015 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目(51308237);华侨大学中青年教师科技创新资助计划(ZQN PY414) |
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| Effect of Heating Regime on Thermal Insulation Properties of Intumescent Coating |
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WANG Lingling1, SUN Yi1, FAN Guangming1, LI Guoqiang2
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1.College of Civil Engineering, Huaqiao University, Xiamen 361021, China;2.College of Civil Engineering, Tongji University, Shanghai 200092, China
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| Abstract: |
| The results of an experimental study were reported on insulation properties of two types of intumescent coating（type W and type S） under the ISO 834 fire and three non standard fire curves which are less severe than the standard fire. After heating test, expansion ratio of intumescent coating and pore structure of chars were measured and compared. Effective thermal conductivities were calculated based on temperature measurements. The results show that expansion ratios can be different when heating speeds up or slows down because more or less gas can be trapped within the coating with varied heating rate. The difference of heating rate affects the matching between timing of gas emission and viscosity of molten polymer, and therefore affects the pore size of intumescent char. The insulative properties of intumescent coating char are better when the expansion ratios are larger and the pore sizes are smaller. The constant effective thermal conductivities derived from non standard fire tests are 65% and 35% higher than that from standard fire tests for type W coating and type S coating respectively, which implies that it is unconservative using standard fire test results to guide design of intumescent coatings under non standard fire conditions which are less severe than the standard fire. |
| Key words: intumescent coating heating regime expansion ratio pore size effective thermal conductivity |
