5.1 This test method is not recommended for acceptance testing of commercial shipments in the absence of reliable information on between-laboratory precision.

5.1.1 If there are differences of practical significance between the reported test results for two laboratories (or more), a comparative test should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, test samples should be used that are as homogeneous as possible, that are drawn from a material from which the disparate test results were obtained, and that are randomly assigned in equal numbers to each laboratory for testing. Other fabrics with established test values may be used for this purpose. The test results from the two laboratories should be compared using a statistical test for unpaired data, at a probability level chosen prior to the testing series. If a bias is found, either its cause must be found and corrected, or future test results must be adjusted in consideration of the known bias.

1.1 This test method covers the determination of fatigue of tire cords in rubber due to compression or extension, or both, using a disc fatigue tester. The fatigue is measured as a loss in strength.

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

1.3 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 and health practices to determine the applicability of regulatory limitations prior to use.