Performance Characteristics of Waterproof Breathable Fabrics

The effect of atmospheric conditions on the water vapour permeability characteristics of waterproof breathable fabrics has been studied. Several types of waterproof breathable fabrics were tested for vapour permeability under a wide range of atmospheric temperatures and relative humidities. It was found that atmospheric conditions have a considerable effect on the vapour permeability characteristics and that there are differences in behaviour between the various types of fabric. The two main variables influencing vapour permeability are identified. Regression equations for the relationship between vapour permeability and the main atmospheric parameter are presented. Conclusions are drawn about the capabilities of the fabrics under conditions of use.