Clothing surface area as related to body volume and clothing microenvironment volume.

The evaluation of clothing surface area becomes important in analyses of heat exchange between the clothed body and its environment. The evidence accumulated in the studies of radiation area has led to the conclusion that the ratio of clothing surface area to body surface area (fcl) may be defined as a function of clothing insulation. However, the effects of clothing fit have been disregarded. Radiation area factors (Ar/AD) were derived from pictures of five subjects wearing four different helicopter pilot suits. While sitting on a seat suspended in the center of a box-shaped frame, photographs were taken of the subjects with a fish-eye lens at 90 equidistant points on the six sides of the frame. The derived Ar/AD of 0.7 +/- 0.18 for the unclothed subjects closely agreed with that reported by Fanger, while it scattered in a relatively wide range for a given suit. The present study proposes a new approach for predicting fcl as related to body volume and the clothing microenvironment volume. The predictions show a good correlation with the values derived from the photographs. It is, therefore, suggested that improvement in the prediction of fcl has been achieved by incorporating clothing fit.