【国外标准】 Standard Test Method for Resistance to Unsnapping of Snap Fasteners

5.1 This test method may be used for acceptance testing of commercial shipments of snap fasteners, but caution is advised since information on between laboratory precision is incomplete. Comparative tests as directed in 5.1.1 are advisable.5.1.1 In case of a dispute arising from differences in reported test results when using Test Method D4846 for acceptance testing of commercial shipments, the purchaser and seller should conduct comparative tests to determine if there is 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 then should be assigned randomly in equal numbers to each laboratory for testing. The average results from the two laboratories should be compared using Student's t-test for unpaired data and an acceptable probability level chosen by the two parties before testing is begun. If a bias is found, either its cause must be found and corrected or the purchaser and seller must agree to interpret future test results in the light of the known bias.1.1 This test method covers the determination of the force required to disengage snap fasteners by a pull perpendicular to and parallel with the plane of the snap fastener.1.2 This test method requires attachment of snaps to specimens using specifications provided by the producers of the snaps.1.3 This test method is used to establish correlation to wear conditions and for comparing different brands and types of snap fasteners.1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.1.5 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.1.6 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.