This test method is considered satisfactory for acceptance testing of commercial shipments of narrow elastic fabrics because the test method is used in the trade for acceptance testing.

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’t-test for unpaired data and an acceptable probability level chosen by the two parties before testing is begun. If bias is found, either the cause must be found and corrected or the purchaser and the supplier must agree to interpret future test results in the light of the known bias.

This test method specifies the use of a static load apparatus. Users of this test method are cautioned that elongation test data obtained using this test method are not comparable to elongation test data obtained using either constant-rate-of-extension (CRE) or constant-rate-of-loading (CRL) type tensile testing machines.

1.1 This test method determines the elongation characteristics of narrow elastic fabrics made from natural or man-made elastomers, either alone or in combination with other textile fibers, when tested with a static load testing procedure before or after laundering. Note 1For determination of similar characteristics using the constant-rate-of-extension (CRE) type tensile testing machine, refer to Test Method D 4964.

Note 2

For determination of similar characteristics using the constant-rate-of load (CRL) type tensile testing machine, refer to Test Method D 1775.

1.2 The use of this test method requires the selection of, or mutual agreement upon, the effective static load at which the test results will be determined.

1.3 Laundering procedures used will be those specified in Test Method AATCC 135 for 3 washing and drying cycles.

1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specifications.

This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.