非膨胀型防火涂料等效热传导系数研究

基于防火涂料标准耐火试验方法,对涂覆非膨胀型防火涂料的钢板试件和工字型钢试件进行了耐火试验,用所得的试件升温曲线计算非膨胀型防火涂料的热传导系数随涂层温度变化曲线.提出将涂层温度为400~800℃时的热传导系数平均值作为涂层等效热传导系数,并用以进行被保护钢构件火灾下升温计算,所得钢构件的升温曲线与试验测得的升温曲线符合良好.参数分析表明,等效热传导系数与试件截面形状系数无关,与涂层厚度相关,表明用小尺寸钢板试件耐火试验结果计算所得的等效热传导系数可用于预测其他被保护钢构件在火灾下的升温.对不同涂层厚度热传导系数进行线性拟合,提出以涂层厚度20mm时的等效热传导系数作为非膨胀型防火涂料等效热传导系数特征值.

Study on Equivalent Thermal Conductivity of Fire Spray Coating

To investigate the feasibility of using a constant thermal conductivity for fire spray coating when calculating protected steel temperature in fire, a series of fire tests on spray coating protected steel sections with a range of section factors and coating thicknesses were tested in fire. The constant thermal conductivity was calculated as the average temperature within the temperature range of interest for fire resistance design and was used to calculate the protected steel temperatures. The calculated steel temperatures were compared with the measured values from the fire tests. The results of this comparison suggest that it is feasible to use a constant thermal conductivity for spray coating. The constant thermal conductivity value would be independent on the steel section factor and dependent on the coating thickness, which indicates that small steel plates can be used as standard specimens to predict the steel temperature of other steel members protected with spray coating. Linear fitting is performed on the equivalent thermal conductivity of different coating thickness, and result of coating thickness 20mm is selected as the characteristic value of the equivalent thermal conductivity of fire spray coating.