ISO 2:1973 Preview
Textiles -- Designation of the direction of twist in yarns and related products
Applicable to yarn intermediates such as slivers, slubbings or rovings; to single yarns, plied yarns, cabled yarns; and to threads, twine, cordage and rope. The direction of twist in yarns, slivers, slubbings and rovings is indicated by the capital letters S and Z. The directions of twist are described in two figures. Designation of complex yarns and related products is explained.