Etude de cas
ASTM D3217Standard Test Methods for Breaking Tenacity of Manufactured Textile Fibers in Loop or Knot Configurations
Significance and Use
5.1 Both the loop breaking tenacity and the knot breaking tenacity, calculated from the breaking force measured under the conditions specified herein and the linear density of the fiber, are fundamental properties that are used to establish limitations on fiber-processing and upon their end-use applications. Physical properties, such as brittleness, not well defined by tests for breaking force and elongation can be estimated from the ratio of breaking tenacity measured in loop or knot tests, or both, and the normal tenacity as measured by Test Method D3822 provided both methods use the same gauge length and strain rate.
5.2 This test method is not recommended for acceptance testing of commercial shipments in the absence of reliable information on between-laboratory precision (see Note 3). In some cases the purchaser and the supplier may have to test a commercial shipment of one or more specific materials by the best available method, even though the method has not been recommended for acceptance testing of commercial shipments. In such a case, if there is a disagreement arising from differences in values reported by the purchaser and the supplier when using this test method for acceptance testing, the statistical bias, if any, between the laboratory of the purchaser and the laboratory of the supplier should be determined with each comparison being based on testing specimens randomly drawn from one sample of material of the type being evaluated.
1. Scope
1.1 These test methods cover the measurement of the breaking tenacity of manufactured textile fibers taken from filament yarns, staple, or tow fiber, either crimped or uncrimped, and tested in either a double loop or as a strand formed into a single overhand knot.
1.2 Methods for measuring the breaking tenacity of conditioned and wet (immersed) fibers in loop and knot form are included.
1.3 Elongation in loop or knot tests has no known significance, and is usually not recorded.
1.4 The basic distinction between the procedures described in these test methods and those included in Test Methods D2101 is the configuration of the specimen, that is, either as a double loop or in the configuration of a single overhand knot.
1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
1.6 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.
1.7 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.