Mechanisms of Heat Flow Through Clothing Insulation

A theoretical model of the combined conductive and radiative heat flow through fibrous insulating materials is presented and compared to experimental values of the thermal resistances of several synthetic fiber battings and of a down and feather mixture. The model is found to account for all the observed heat flow if appropriate infrared absorption constants are assumed. No evidence of convective heat transfer is found, even in very low-density battings. The differences in resistance per unit thickness among the various materials may be attributed to their different absorption constants.