Comparison of Test Methods for Measuring Water Vapor Permeability of Fabrics

There are a variety of test methods in use to measure the ability of fabrics to transport water vapor. They vary with respect to construction mechanisms, test conditions, and measurement parameters. Five testing instruments plus a new test apparatus were employed to evaluate the water vapor transport properties of fabrics with low, medium, and high vapor permeability. The test results show that the desiccant inverted cup method generated the highest water vapor transmission rate, followed by the new method, the dynamic moisture permeation cell (DMPC), the inverted cup method, and the upright cup method. The statistical analyses indicated that the new method is in good agreement with other standard test methods. Most of the correlations between any two of the methods are strong, except the upright cup method. The new test method offers a short test time and calls for a small sample size.