The design of effective clothing for use in windy conditionS

In windy conditions, air penetration into permeable clothing is a major cause of a reduction in thermal insulation[1]. The traditional method used for preventing air penetration is to cover the clothing systems with outer fabrics which have low air permeabilities. However, fabrics which are impermeable or have low permeabilities are inherently highly resistant to the moisture vapour transmission. Consequently, when such clothing systems are worn in cold and windy conditions, condensation often occurs inside the clothing system, resulting in severe discomfort, such as "after chill", which can be experienced by the wearer. Although a wide range of breathable or water vapour permeable fabrics have been introduced during recent years in an attempt to alleviate this problem, research has shown that the breathabilities of such fabrics are insufficient to prevent condensation without due regard to functional garment design[2]. As a consequence, it is desirable to construct wind protective clothing systems by using outer fabrics which are permeable to air. On this basis, two moderately permeable fabric layers were proposed as alternative covers to clothing systems for use in windy conditions[3]. Based on the understanding of the mechanism of the air penetration into permeable clothing systems, this paper proposes three methods for the design of both moisture vapour permeable and wind protective clothing systems, using air permeable fabrics as covers. These design methods are verified by testing clothing assemblies on a cylindrical togmeter in a wind tunnel. © 1989, MCB UP Limited