Standard Test Methods for Stretch Properties of Fabrics Woven from Stretch Yarns.
5.1 These test methods are used to determine the stretch, growth and recovery properties that garments made with the fabric tested may be expected to exhibit during use.
5.2 These test methods is not recommended for acceptance testing of commercial shipments because the between-laboratory precision is known to be poor.
5.2.1 If there are differences of practical significance between reported test results for two or more laboratories, comparative tests should be performed by those laboratories to determine if there is a statistical bias between them, using competent statistical assistance. Use test samples that are as homogeneous as possible, are drawn from the material from which the disparate test results were obtained, and are randomly assigned in equal numbers to each laboratory for testing. The test results from the two laboratories should be compared using a statistical test for unpaired data, at a probability level chosen prior to the testing series. If a bias is found, either its cause must be found and corrected, or future test results for that material must be adjusted in consideration of the known bias.
5.3 Some stretch fabrics are constructed with stretch yarns in only the filling direction. Consequently, for those fabrics, only the filling direction needs to be tested.