Abstract: This study focuses on addressing thermal comfort challenges associated with the hermetic construction of chemical protective clothing. This study employed a thermal manikin experimental platform to investigate the relationship between air gap thickness and manikin surface temperature under multifactorial conditions by systematically measuring temperature variations across different air gap thicknesses, ambient temperatures, and activity intensities, thereby analyzing the impact of air gap thickness on microclimate heat transfer. The results demonstrate that when the air gap thickness reduced from 55 mm to 10 mm, the temperature rise amplitude of the manikin surface increased, indicating that increasing the air gap thickness significantly reduces the manikin's surface temperature. The manikin's surface temperature increased by 0.89 ℃ at 65 W/m² and 1.54 ℃ at 110 W/m² thermal loads, revealing a positive correlation between temperature rise amplitude and activity intensity. The temperature changes of the manikin corresponding to ambient temperatures of 32, 25, 15, 10 ℃ are 1.59, 1.54, 0.42, 0.12 ℃, respectively. The decrease in the thickness of the air layer results in a significant increase in the temperature rise of the manikin as the ambient temperature increases.

Key words: airtight chemical protective clothing, heat transfer, thermal manikin, air gap, ambient temperature, exercise intensity