Thermal comfort characteristics of textile apparel fabrics

Nine fabrics of various fiber content and construction were investigated. Seven of the fabrics represented materials that could be used for an indoor jacket and two fabrics represented materials that could be used for a shirt or blouse.

Fabric physical properties were measured according to standard textile testing procedures. The insulation value of the fabrics was measured using the heat flow and mass transfer apparatus which was designed and fabricated at the USDA Textiles and Clothing Laboratory, Knoxville, Tennessee.

The experiments were conducted with the fabrics in spatial configurations of single fabrics, jacket and shirt fabric touching, jacket and shirt spaced 0.125" apart, jacket and shirt fabric spaced 0.250" apart.

Each test was made at three different combinations of temperature and relative humidity to simulate conditions next to the skin and in the ambient environment. Saturated salt solutions were used to maintain a constant relative humidity.

Results of the study indicate that the layering of the fabrics is the most significant factor in thermal insulation for the fabrics under investigation; insulation increases with an increase in air space. The temperature-relative humidity was also a significant factor in providing insulation.

Fabric thickness was found to be the only statistically significant physical property under the prescribed conditions. A quantitative analysis of fabric surface indicated that the surface hairiness could possibly be a contributing factor to insulation value; the fabrics with the most protruding surface hairs gave the highest insulation values.