ASTM D4964-96(2016)

5.1.1 In case of a dispute arising from differences in reported test results when using this test method for acceptance testing of commercial shipments, the parties should conduct comparative tests to determine if there is a statistical bias between their laboratories. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the two parties should take a group of test specimens that are as homogeneous as possible and that are from a lot of material of the type in question. The test specimens should then be randomly assigned in equal numbers to each laboratory for testing. The average results from the two laboratories should be compared using student's 5.2 This test method specifies the use of the CRE-type tensile testing machine. Users of this test method are cautioned that loop tension test data obtained using this method are not comparable to tension test data obtained using Test Method D1775 because of the differences in testing machines. Test Method D1775 uses a CRL-type tensile testing machine.

5.3 The loop tension and extension relationship of an elastic fabric is an important criterion for judging the suitability of the fabric for various end uses, such as: foundation garments, brassieres, and swimsuits.

5.4 Data from loop tension-recovery curves can be compared only if the tension testing machine, rate-of-extension, maximum loading (or extension), and specimen specifications are comparable. Since different machine set-ups will cause different results on the same fabric, machine set-ups must always be specified before making a test and be reported with the test results.

5.5 The test for measuring loop tension at specified elongation(s) is used to determine the tension of an elastic fabric when subjected to a specified elongation which is less than the elongation required to rupture the fabric. The test prescribes points of measurement on the extending (outgoing) cycle only.

5.6 The test for measuring elongation at specified tension(s) is used to determine the elongation of an elastic fabric when subjected to a specified loop tension which is less than the tension required to rupture the fabric. The test prescribes points of measurement on the loading (outgoing) cycle only.