Textile-Designation of the direction of twist in yarns and related products
ISO 2:1973 applies to yarn intermediates like silvers, rovings, piled yarns, single yarns, cable yards, threads, ropes, cordage, twine, etc
The direction of the twist is indicated in the capital letters S & Z, in silvers, yarns, slubbings, and rovings. The handedness of the twist is the direction of the twist as they progress away from the observer, Z twist is required to be right-handed & S twist is required to be left-handed.
The directions are described in two figures. The designation of the yarns and relevant products is explained.
This standard was developed in the year 1973 by ISO/TC 38/SC 23 committee and was adopted by ISO.
Read About: ISO 2145:1978(EN)