This test method for yarn number is satisfactory for acceptance of commercial shipments and is used in the trade.

In case of a dispute arising from differences in reported test results when using this Test Method for acceptance testing of commercial shipments, the purchaser and the supplier should either use the referee Test Method D1907 for yarn number or 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 a probability level chosen by the two parties before the testing is begun. If a bias is found, either its cause must be found and corrected or the purchaser and the supplier must agree to interpret future test results with consideration to the known bias.

This test method is also used for the quality control for both filament and spun yarns.

1.1 This test method covers the measurement of yarn number of filament and spun yarns using automated testers. Some of the instruments are stand-alone and others are optional modules for instruments that perform additional tests.

1.1.1 The instruments are capable of measuring yarn numbers up to 4000 dtex (3600 denier).

Note 1—For determination of yarn number by use of reel and balance, refer to Test Method D1907.

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 non-conformance 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 and determine the applicability of regulatory limitations prior to use.