The effect of fabric air permeability on clothing ventilation

Abstract Dry and evaporative heat losses of clothed people are highly affected by the air exchange between the clothing microclimate and the environment. This air exchange, or clothing ventilation, is highly affected by the air permeability of the fabric materials as well as the clothing design. To examine the effect of the air permeability of fabric on clothing ventilation, the ventilation rate of three suits with identical design but with different air permeability (air resistance: 0.3 and 20.5 kPa·s −1 ·m −1 , and impermeable) was determined for subjects under the following conditions: standing still or walking, both in still air and in air moving at 1 m s −1 . In addition tests were performed with the suit's openings at neck and wrist cuffs both opened and closed, under the same conditions, to determine the effect of the openings on ventilation. The microclimate ventilation was significantly higher in the more permeable suit compared with the less permeable ones when standing with no wind and when walking with wind. The air permeability of the two permeable suits increased ventilation significantly when walking with no wind and when standing with wind. These increases in ventilation ranged from 30 to 90 l min −1 and corresponded to the level of clothing ventilation required to remove sweat produced as a result of light work. Compared to the suits with the openings tightened, the suits with the collars and cuffs open showed greater ventilation, but this increase in ventilation made a smaller difference as the air permeability of the fabric increased. These data imply that the air permeability of fabric can induce the proper dry and evaporative heat loss for keeping comfortable under light-work conditions, provided that clothing apertures are considered as a combined factor.