This International Standard specifies a method for the determination of the direction of twist in single yarns and the amount of twist, in terms of turns per unit length, by the indirect untwist/retwist method. This International Standard is applicable to single spun yarns. This International Standard is not applicable to: a) open-end spun yarns; b) false twist and self twist yarns; c) air-jet yarns; d) yarns that stretch more than 0,5 % when the tension increases from 0,5 cN/tex to 1,0 cN/tex. NOTE Such yarns may be tested under special conditions of tension which are accepted by all parties interested in the test results. e) yarns that are too large to permit their being placed in the clamps of testing apparatus without crushing or distortion severe enough to affect the test results. The method is designed primarily for yarns in packages, but by the application of special precautions the procedures can be used for yarns taken from fabrics.