CAN/CGSB-4.2 No 8.2-2004/ISO 2601:1995

This National Standard of Canada is equivalent to International Standard ISO 2061:1995. 1. Scope 1.1 This International Standard specifies a method for the determination of the direction of twist in yarns, the amount of twist, in terms of turns per unit length, and the change in length on untwisting, by the direct counting method. 1.2 This International Standard is applicable to: a) single yarns (spun or multifilament); b) folded (plied) yarns; c) cabled yarns. Separate procedures are given for each type of yarn. The method is designed primarily for yarns in packages, but with special precautions the procedures can be used for yarns taken from fabrics. It is not suitable for the determination of twist in a monofilament. Note 1 - See also ISO 1890 (1) Reinforcement Yarns - Determination of twist, which was prepared especially for the needs of glass textile technology, and ISO 7211-4:1984, Textiles - Woven fabrics - Construction - Methods of analysis - Part 4: Determination of twist in yarn removed from fabric. (1) To be publised. (Revision of ISO 1890:1986) 1.3 This International Standard covers the determination of twist in plied and cabled yarns as follows: - In plied yarns: the final twist of the plied yarns and the original twist of the single yarn before plying. - In cabled yarns: a) the final cabling twist of the yarn; b) the original twist of the plied yarn after plying, but prior to the last stage of processing; c) the twist of the single yarn before plying. 1.4 If desired, the twist of single and plied yarn components as they lie in the final structure may be determined by the special procedure given in 10.5.7. 1.5 The International Standard is not applicable, except by agreement, to yarns which stretch more than 0.5% when the tension increases from 0.5 to 1.0 cN per unit linear density of the yarn expressed in tex. Such yarns, may be tested under special conditions of tension which are accepted by all parties interested in the test results. 1.6 This International Standard is not suitable for products of open-end spinning and intermingled (interlaced) multifilament yarns. 1.7 This International Standard is not applicable to yarns which are too large to permit their being placed in the clamps of the testing apparatus without crushing or distortion severe enough to affect the test results.