ISO 7211-4:1984

Textiles — Woven fabrics — Construction — Methods of analysis — Part 4: Determination of twist in yarn removed from fabric

Only applicable to yarns spun on conventional systems and not applicable to OE (open-end spun) or interlaced yarns, for example. A length of yarn is removed from the fabric and, while under tension, is secured in two clamps which are at a known distance apart. One of these clamps is then rotated until all twist is removed from the length of yarn.