摘要： 钢结构防火涂料在电缆工程中，可用于对明敷穿管电缆的防火保护，但防火涂料的种类和厚度与保护效果之间没有明确的规律和依据可循。文章在实验研究的基础上，运用传热学理论建立了电缆穿涂敷钢结构防火涂料后在火灾条件下的内部温度分布模型，并采用 MATLAB软件求得了模型的数值解，并据此获得电缆绝缘失效时间。对电缆在90种不同保护条件下的绝缘失效时间进行了计算，并对计算结果进行拟合，得到失效时间与防火涂料涂层膨胀厚度及热扩散系数之间的函数关系式，可为电缆防火设计、施工时确定涂料选型及涂刷厚度等参数的定量参考依据。

关键词: 钢结构防火涂料, 电缆, 绝缘失效, 保护作用, 数值计算

Abstract: In cable projects, steel fire retardant coating can be used for fire protection of surface laid cable which was laid in cable conduit. However, there is no clear rule and basis to follow between the type and thickness and the performance of fire retardant coating. A modelsof inner temperature distribution of a cable conduit protected with fire retardant coating was established when it was exposed to fire condition in basis of experiment findings and heat transfer theory. The time-temperature relation at each point in the cable was obtained by MATLAB, and the cable insulation failure time could be calculated. The insulation failure time of cable protected by 90 different ways were computed, the relation formula of failure time and intumescent coating thickness and thermal diffusivity was fitted. The formula could be used as a quantitative reference for the cable fire protection design and construction.

Key words: steel fire retardant coating, cable, failure of insulation, protection, numerical calculation