The effect of wind, body movement and garment adjustments on the effective thermal resistance of clothing with low and high air permeability insulation

Using a thermal manikin, the total clothing thermal resistance (IT) of two clothing ensembles with the same air-impermeable outer layer but with either high or low air permeability insulation was determined at three different walking (0, 1 and 2.5 km.h−1) and wind (0.1, 1 and 2.5 m.s−1) speeds. Three clothing ‘configurations’ (outer garment sealed, outer garment open, outer and mid layer garment open) were also tested. The IT of the high-permeability insulation was lower than that of the low-permeability insulation, indicating more heat transfer by radiation and the possibility of natural convection between clothing layers. When the outer garment was opened to favor ventilation, the IT of the high-permeability insulation was reduced by between 15% (surface-weighted average) and 25% (locally) more than that of the low-permeability insulation, but when the outer garment was ‘sealed’, the IT of the high-permeability insulation was not reduced by a greater extent. The use of high-permeability insulation may allow clothing designers to create more comfortable clothing by encouraging ventilation, particularly by creating localized cooling.