Ancient man draped his body with skins and hides to protect himself from his environment. In recent years, attention has focused on developing a thermally comfortable environment in which man functions and carries on his life activities. Thermally neutral controlled envrionments have received considerable attention. which is commendable. At the same time, the function of clothing has received lesser attention than other environmental factors.

Rohles (1) identifies clothing in "The Ecosystem Complex" as a reciprocative factor to be considered or controlled in environmental research. Review of comfort research literature indicates clothing has more often been controlled and less often investigated. Clothing has been an integral consideration in the KSU-ASHRAE Comfort Envelope (2) and the Fanger comfort equation (3). Fanger as well as other members of ASHRAE indicated a great need for research concerning the transfer of heat through clothing systems since little research of this nature had been done. Most of that which had been done involved military and aeronautical application and usually corrsidered clothing suitable for severe environmental conditions.

The need for clothing research as it related to thermal comfort prompted an ASHRAE supported research investigation by the Institute for Environmental Research at Kansas State University. Efforts resulted in the development of a Clo Value Index (4) assessing clo values for many individual items of clothing and several ensembles, and a linear regression formula (5) which allows the assessing of clo value for an entire ensemble from individual items of clothing.