7211/4 International Standard (TSO INTE RNATIONAL ORGANIZATION FOR STANDARDIZATION MEKAYHAPOAHAR OPrAHM3ALWA nO CTAHAAPTW3AuWMORGANISATION INTE RNATIONALE DE NORMALISATION Textiles - Woven fabrics - Construction - Methods of analysis - Part 4: Determination of twist in yarn removed from fabric Textiles - Tissus - Construction - Methodes d'analyse - Partie 4: Détermination de la torsion d'un fil preleve dans un tissu First edition - 1984-03-15 SO7211/4-1984(E) UDC 677.064: 677.014.885 Ref.No.ISO7211/4-1984 (E) Descriptors : textiles, woven fabrics, tests, determination, twisting, yarns, test specimens, test equipment, test results. Price based on 2 pages Popyintl No reproduction or networking permitted without license from IHS Not for Resale Foreword ISO(theInternational OrganizationforStandardization)is a worldwide federationof national standards bodies (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 authorized has the and non-governmental,in liaison withIsO,also take part in the work. Draft International Standards adopted by the technical committees are circuiated to the member bodies for approval before their acceptance as International Standards by the ISO Council. International Standard ISO7211/4 4wasdeveloped by Technical Committee ISO/Tc 38, Textiles, and was circulated to the member bodies in November 1982. Australia Iran Romania Belgium Iraq South Africa, Rep. of Brazil Israel Spain Bulgaria Italy Sweden China Jamaica Tanzania Czechoslovakia Japan Thailand Egypt, Arab Rep. of Korea, Rep. of Turkey Finland Mexico United Kingdom Germany, F.R. Netherlands USA Ghana New Zealand USSR Hungary Poland Venezuela India Portugal The member bodies of the following countries expressed disapproval of the document on technical grounds: Canada France International Organization for Standardization, 1984 Printed in Switzerland No reproduction or networking permited withoutlicense from IHs Not for Resale ISO 7211/4-1984 (E) INTERNATIONALSTANDARD Textiles - Woven fabrics Construction - Methods of analysis Part 4: Determination of twist in yarn removed from fabric 0 Introduction 3Principle Although the twist in a yarn removed from a fabric is deter- A length of yarn is removed from the fabric and, while under mined on the same apparatus as is used for determining the tension, is secured in two clamps which are at a known twist in yarn withdrawn from a package (see IS0 2061), there distance apart. One of these clamps is then rotated until all are some differences of technique. In particular, care must be twist is removed from the length of yarn. taken to avoid alteration of twist during transfer of the yarn from the fabric to the apparatus. 4 Apparatus A standard mounting tension is also required to remove the crimpwhich ispresent inmostyarns asaresult ofincorporation 4.1 Twist counter, consisting of a pair of clamps, one of in fabrics. which shall be rotatable in either direction and positively con- nected to a revolution counter. The clamps shall be adjustable Alterations intwistmayoccur whenayarn is incorporated into or removed from a more complex structure. To determine the to permit testing yarn lengths as specified in the table. For cer- tain folded, cabled and similar yarns, it may be convenient to twist in the single yarns from a sample of the folded yarn, make provision for displacement of the non-rotatable clamp to however, it is essential to untwist the latter, thus re-inserting allow for change in length of the test specimen during un- twist in the single yarns. The results of twist tests on these single yarns will, therefore, indicate the state of the yarn prior twisting. Means shall be provided for applying the appropriate straightening tension (see ISo 7211/3) prior to clamping. to the folding operation and not when it is functioning as a component of the folded yarn. 4.2 D