Z (ISO NTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKIYHAPOIHAS OPIAHH3ALINS IHIO CTAHIAPT3ALIWN.ORGANISATION INTERNATIONALE DE NORMALISATION Textiles -- Designation of the direction of twist in yarns and related products First edition - 1973-09-15 Ref. No. ISO 2-1973 (E) UDC 677.061 2-1973 Descriptors : textiles, yarns, twisting, orientation, designation. Price based on 1 page nsefromIHS Not for Resale FOREWORD sO (the International Organization for Standardization) is a worldwide federation of national standards institutes (isO Member Bodies). The work of developing International Standards is carried out through ISO Technical Committees. Every Member Body interested in a subject for which a Technical Committee has been set up has the right to be represented on that Committee. International organizations, governmental and non-governmental, in liaison with isO, also take part in the work. Draft International Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the ISO Council. Prior to 1972, the results of the work of the Technical Committees were published as iso Recommendations; these documents are now in the process of being transformed into International Standards. As part of this process, International Standard ISO 2 replaces ISO Recommendation R 2-1966 drawn up by Technical CommitteeISO/TC38,Textiles. The Member Bodies of the following countries approved the Recommendation : Australia Hungary Portugal Austria India Romania Belgium Israel South Africa, Rep. of Canada Italy Sweden Chile Mexico Switzerland Czechoslovakia Netherlands United Kingdom U.S.A. Denmark New Zealand Finland Norway U.S.S.R. France Poland Yugoslavia No Member Body expressed disapproval of the Recommendation. @ International Organization for Standardization, 1973 PrintedinSwitzerland ariz itted without license from IHS Not for Resale ISO 2-1973 (E) INTERNATIONAL STANDARD Textiles -- Designation of the direction of twist in yarns and related products 1 SCOPEAND FIELDOF APPLICATION b) Z twist. The product has Z twist if, when it is held in a vertical position, the spirals or helices formed by the This International Standard specifies the method of fibres or filaments around its axis incline in the same designating the direction of twist in textile yarns. It is direction as the central portion of the letter z (see applicable to yarn intermediates such as slivers, slubbings, Figure 2). or rovings; to single yarns, plied yarns, cabled yarns; and to NOTE - Small letters s and z may be used if necessitated by special threads, twine, cordage and rope. circumstances. OF SINGLE YARNS AND 2 DESIGNATIONS 3 DESIGNATIONS COMPLEX YARNS AND INTERMEDIATES RELATEDPRODUCTS The direction of twist in yarns, slivers, slubbings and The letters S and Z are used to indicate the direction of the rovings is indicated by the capital letters S and Z, thus : together to produce a plied or cabled yarn, or a thread, a) S twist. The product has S twist if, when it is held in twine, cordage or rope. a vertical position, the spirals or helices formed by the fibres or filaments around its axis incline in the same NOTE -- The letters S and Z may be used to indicate the direction direction as the central portion of the letters (see of winding (inclination or lay) of a yarn wound around a wire or Figure 1). any other core. FIGURE 2 - Z twist FIGURE 1 - S twist Copyright International Organization for Standardization e from IHS Not for Resale