48—AN INVESTIGATION OF THE PHYSIOLOGICAL VALUE OF SORPTION HEAT IN CLOTHING ASSEMBLIES

Abstract

This paper gives the historical background of sorption heat in textile materials and makes an appreciation of the physics of the phenomenon, together with its physiological implications. Details are given both of the laboratory evaluation of the ‘comfort’ properties of the fabrics or garments used and of a series of physiological investigations aimed at assessing the value of sorption heat to the wearer.

The physiological experiments were performed on groups of men wearing clothing assemblies of matched construction made from fihres having very large differences in regain characteristics, namely, wool and Terylene. The conditions under which experiments were made were as follows:

1. at rest in simulated environments (indoor conditions 68°F (20°0) and 43% r.h., outdoor damp–cold at 43°F (6·1°C and 93% r.h.;

2. as in (1) with a 5-miles/hr turbulent wind;

3. sweating from work in a cool environment (58°F (14·4°C) and 50% r.h.); a

4. sweating slightly at rest in a hot–dry environment (88°F (31·l°C) and 26% r.h.) and then being exposed to winter outdoor conditions as in (1) above.

Results in brief show no consistent, statistically significant physiological differences between the wool and Terylene clothing assemblies on exposure to damp–cold conditions. Differences between means, when present, were marginal. However, a small significant mean difference (higher for wool) was found in weighted-average skin temperature in the unusual environmental conditions indicated as (4) above. Sorption-heat eflFects were shown to exist in a physical model for wool (and, to a less extent, Terylene) clothing under both warmhumid and damp–cold conditions.

It is concluded that, under the conditions of the investigation, the sorption heat of textile materials has not shown convincing evidence for its physiological value in clothing worn under simulated damp–cold winter conditions.