ASTM D7142-05(2021) PDF

SIGNIFICANCE AND USE 5.1 Both test methods are considered satisfactory for acceptance testing of commercial shipments of garments with prong-ring type snap fasteners. 5.1.1 In case of dispute arising from differences in reported test results when using this test method for acceptance of commercial shipment, the purchaser and the supplier 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 appropriate statistical analysis and an acceptable probability level chosen by the parties before testing is begun. If a bias is found, either the cause must be determined and corrected, or the purchaser and supplier must agree to interpret future test results with consideration to the known bias. 5.2 Comparison of results from test equipment operating on different principles is not recommended. In cases of conflict between the test results achieved with manual test equipment (Option 2) and motorized CRE (constant rate of extension) tensile testing machine (Option 1), the results from the motorized equipment shall take precedence. 5.3 This test method may be used to determine the compatibility of prong-ring type snap fasteners and fabrics for use in apparel. In which case, the fasteners are attached to the fabric in the manner in which they will be used and the combined units tested. See Annex A1. SCOPE 1.1 This test method covers the determination of the holding strength of a prong-ring to the socket or stud of a snap fastener using a tensile testing machine (Option 1) or a manual test stand and force-measuring gage (Option 2). 1.2 This test method is applicable to prong-ring type snap fasteners in garments or to be attached to fabrics intended for use in apparel (see Annex A1). 1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are shown in parentheses. 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 non-conformance with the standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.