DIN EN ISO 13015:2013-12

Textile and clothing manufacturers assign a lot of importance to knowledge of the widthway distortion. In the case of woven fabrics with patterns or in which the weft threads are rather visible, the appearance of a textile article could be compromised. With some rare exceptions, the two sets of threads in woven textile fabrics are intended to lie straight and at right angles. If a fabric does not meet either of these requirements, it is described as distorted. Difficulties in making up may then arise and the made-up article may fail to function properly. The distortion may also detract from the appearance of fabric with checked patterns or coloured weft effects such as plaids or stripes. It is therefore desirable to have a means of specifying and measuring the distortion in woven fabric in terms of bow and skew. This standard specifies a method for the determination of the distortion of a woven fabric in which the weft yarns are, in principle, perpendicular to the warp yarns. In a piece of the woven fabric, laid on a flat surface and without tension, skew and bow are characterized as follows: Overall skew is specified as the distance between one end of a weft yarn and the point on the same edge intersected by a line running at right angles from the other end of the weft yarn to the fabric length. Local skew is specified as the distance between one end of a weft yarn to its perpendiculars to the warp running at right angles to a portion of the fabric length. Weft bow is specified (in a normative Annex) as the total perpendicular distance by which a weft yarn deviates from a straight line joining the far ends of the weft yarn. Warp bow is specified (in a normative Annex) as the greatest perpendicular distance between the edge of the fabric and a straight line joining two selected points on the edge. This document (EN ISO 13015:2011) has been prepared by Technical Committee ISO/TC 38 "Textiles" in collaboration with Technical Committee CEN/TC 248 "Textiles and textile products", the secretariat of which is held by BSI (United Kingdom). The responsible German committee is NA 062-05-21 AA "Physikalisch technologische Prüfverfahren für Textilien" ("Physical and technological test methods for textiles") of the Materials Testing Standards Committee (NMP) at DIN.