Standard Test Method for Twist in Single Spun Yarns by the Untwist-Retwist Method

1.1 This test method describes the determination of twist in single spun yarns when only an approximation of the true twist is required. For a more accurate method see Test Method D1423.

1.2 This test method is applicable to spun single yarns in continuous lengths, and also to spun yarns raveled from fabrics, provided specimens at least 200 mm (8 in.) long can be obtained.

1.3 This test method is not applicable to yarns that have been subjected to any chemical treatment or mechanical process that results in a condition that prevents easy removal of twist from the yarn, nor to bast fiber yarns in which the bundles of fibers split, nor to yarns that extend more than 5.0% when tension is increased from 2.5 to 7.5 mN/tex (0.25 to 0.75 gf/tex).

1.4 This test method has been found satisfactory for use in determining twist in all single ring spun yarns and 100% cotton open-end yarns. For all open-end spun yarns that are not 100% cotton this test method has not been found to be satisfactory for determining twist but may be used to measure deviation from an average value.

1.5 This specification shows the values in both inch-pound units and SI units. The "inch-pound" units is the technically correct name for the customary units used in the United States. The "SI" units is the technically corrected name for the system of metric units known as the International System of Units. The values stated in either acceptable metric units or in other units shall be regarded separately as standard. The values expressed in each system may not be exact equivalents; therefore, each system must be used independently of the other, without combining in any way.

1.6 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.>