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 D 3822.

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.