Regional Water-Vapor Partial-Pressure Responses in Film-Laminated Hardshell Jackets: An Exploratory Randomized Crossover Wear Study

This exploratory study examined regional water-vapor accumulation in four commercial film-laminated hardshell jackets during a structured wear protocol. Three healthy men each completed one trial per jacket in a randomized crossover design at 20 ± 2 °C and 60 ± 4% relative humidity. Temperature and relative humidity were recorded at the underarm (P-1) and chest (P-2), with local sweat rate measured at P-2. Water-vapor partial pressure (pv) was calculated to describe the combined temperature–humidity response; pressure differences were referenced to the nominal ambient value of 1.40 kPa. Reported mean P-1 pv was lowest for B (3.76 kPa), whereas P-2 pv and local sweat rate were lowest for C (3.29 kPa and 0.33 mg cm−2 min−1). The displayed trajectories suggested greater separation during a period of 0–15 min and convergence of relative humidity after approximately 16 min. These findings support the region-specific assessment of garment microclimates and show how dynamic pv analysis can complement standard material testing when screening garment designs.