THE CLO - A UTILITARIAN UNIT TO MEASURE WEATHER CLIMATE COMFORT/

A number of indices have been devised to assess human comfort under a variety of atmospheric conditions. In the USA the most widely used, pa rticularly by the broadcast media, are windchill for cold conditions a nd the Heat Index for hot. Both provide measures of instantaneous cond itions and are useful as weather stress guides; each is evaluated in t his presentation. Thereafter, the do (a measure of comfort that provid es an indication of the clothing required under a given set of conditi ons) is examined as a potential alternative comfort index to those in current use. Derived many years ago, the do expresses the resistance t o heat transfer by clothing and is expressed relative to units of ther mal insulation. Derived do values are compared with values of Heat Ind ex and windchill for the same data sets at a selected station and sign ificant relationships are obtained. The results indicate that the do v alue could be used as an alternative to the current weather stress ind ices. Of note is that the do permits use of a single index applicable to all seasons. The do, however, may also be used as a guide to relati ve comfort representing long-term average as well as extreme, instanta neous atmospheric conditions. It serves as a climatic index by providi ng a seasonal clothing index. To demonstrate its potential value, seas onal clothing guides for the USA, Europe, and Australia are provided.