在高温环境下工作时，人们需要穿着专用服装以避免灼伤。专用服装通常由三层织物材料构成，记为I、II、III层，其中I层与外界环境接触，III层与皮肤之间还存在空隙，将此空隙记为IV层。确定高温作业下的人体皮肤温度以及热防护服最优厚度，有利于设计出更合理安全的热防护服。当人体处于高温环境中，穿着热防护服，分别讨论：1) 当环境温度为65℃、IV层的厚度为5.5 mm时，确定II层的最优厚度，确保工作60分钟时，假人皮肤外侧温度不超过47℃，且超过44℃的时间不超过5分钟；2) 当环境温度为80℃时，确定II层和IV层的最优厚度，确保工作30分钟时，假人皮肤外侧温度不超过47℃，且超过44℃的时间不超过5分钟。运用有限差分法、最小二乘法、双变量优化等方法分析数据，进而得到安全风险系数，以及确定热防护服各层材料的最优厚度。
When working in a high temperature environment, people need to wear special clothing to avoid burns. The special clothing is usually composed of three layers of fabric materials, which are re-ferred to as layers I, II and III, wherein the layer I is in contact with the external environment, and there is a gap between the layer III and the skin, and the gap is recorded as an IV layer. Determin-ing the skin temperature of human body under high temperature operation and the optimal thickness of thermal protective clothing is conducive to designing more reasonable and safe thermal protective clothing. When the human body is in a high temperature environment, wearing thermal protective clothing, respectively, to discuss: 1) When the ambient temperature is 65？C and the thickness of the IV layer is 5.5 mm, the optimal thickness of the II layer is determined to ensure that the skin of the dummy is 60 minutes after work. The outside temperature does not exceed 47？C, and the time exceeding 44？C does not exceed 5 minutes; 2) when the ambient temperature is 80？C, the optimal thickness of layer II and IV is determined to ensure that the outside temperature of the dummy skin does not exceed 47？C after working 30 minutes, and more than 44？C for less than 5 minutes. The finite difference method, least squares method, and bivariate optimization method are used to analyze the data, and then the safety risk coefficient is obtained, and the optimal thickness of each layer of the thermal protective clothing is determined.
