Tso 920 NTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKIYHAPOHAA OPIAHW3ALM HIO CTAHIAPTH3ALIH.ORGANISATION INTERNATIONALE DE NORMALISATION Wool -- Determination of fibre length (barbe and hauteur) using a comb sorter Laine - Détermination de la longueur de barbe et de la hauteur des fibres sur appareil a peignes First edition - 1976-10-15 Ref. No. 1SO 920-1976 (E) ISO 920-1976 (E) UDC 677.31/.34.017.222.23 Descripto : natural fibres, animal fibres, wool fibres, dimensional measurement, length. Price based on 5 pages ed without license from IHS Not for Resale FOREWORD ISO (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 in the process of being transformed into International Standards. As part of this process, Technical Committee technically suitable for transformation. International Standard IsO 920 therefore to which it is technically identical. IsO Recommendation R 920 had been approved by the member bodies of the following countries : Australia Ireland South Africa, Rep. of Spain Austria Israel Chile Italy Sweden Japan Switzerland Czechoslovakia Denmark Korea, Rep. of Turkey France New Zealand United Kingdom Hungary Norway U.S.S.R. India Portugal Yugoslavia Iran Romania The member bodies of the following countries had expressed disapproval of the Recommendation on technical grounds : Germany Belgium Egypt, Arab Rep. of Netherlands The member bodies of the following countries disapproved the transformation of the Recommendation into an International Standard : Germany U.S.S.R. @ International Organization for Standardization, 1976 · Printed in Switzerland itted without license from IHS Not for Resale ISO 920-1976 (E) INTERNATIONAL STANDARD Wool -- Determination of fibre length (barbe and hauteur) using a comb sorter 1 SCOPE AND FIELD OF APPLICATION 4 PRINCIPLE A numerical sample of the fibres is taken and the fibres are This International Standard specifies a method for the classified by lengths. They are then divided into length determination of wool fibre length, barbe and hauteur, and groups and weighed. their coefficients .of variation, by means of a comb sorter. This method is applicable to twistless combed wool slivers and to prepared wool slivers (rovings). 5 APPARATUS 2 REFERENCE 5.1 Balance, having an accuracy of 1 mg. iSO 139, Textiles -- Standard atmospheres for conditioning and testing. 5.2 Comb sorter, consisting basically of a bed of .combs which . can be lowered successively and of which the 3 DEFINITIONS spacings determine the classes of the fibre lengths. 3.1 barbe : The mean length of the fibres of a sliver or of This apparatus shall permit the following operations : a roving, calculated from the proportions by mass of the successive draws of several tufts of fibres at the fibres in the sliver or the roving. squared-off end of a sliver or a roving; If - the deposition of these tufts as they are drawn onto n1, n2 ... represent the number of fibres in each length the comb bed so that the aligned ends of the combed fibres in each tuft are placed on the last comb; group, represent the length of each group determined the removal of the fibres which project beyond each L1, L2 ... on partially decrimped fibres, expressed in millimetres, comb by means