The thermal conductivity of textiles

A review is given of measurements of the thermal conductivity of natural clothing fibres and of formulae that have been proposed for the overall thermal conductivity of fibre-air mixtures in terms of their density and fibre conductivity. Measurements of the conductivity of wool felts ranging in density from 0.01 to 1.0 gm./cc. have been made, using Hercus and Laby's method for determining the conductivity of air. The conductivity of solid keratin (horn) has also been measured by the Lees disc method, and it is suggested that wool fibres and horn have identical conductivities of 4.62×10-4 c.g.s. units at 0.7% regain and 5.32×10-4 c.g.s. units at 10.7% regain. The data given for wool felts and horn are used to obtain an empirical relation between conductivity and bulk density. Results obtained with cotton fabrics indicate that published values of the thermal conductivity of cotton fibres are too high.