BS ISO 7211-6-2020 Textiles一Methods for analysis of woven fa brics construction Part 6: Determination of the mass of warp and weft per unit area of fabric.
This document specifies methods for determining the mass of the warp and weft threads per unit area of fabric after the removal of any non-fibrous matter.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 139. Textiles — Standard atmospheres for conditioning and testing
ISO 1833-1. Textiles — Quantitative chemical analysis — Part 1: General principles of testing
3 Terms and definitions
No terms and definitions are listed In this document.
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Method A: The outline of the fabric specimen to be dissected is marked in the form of a square or rectangle, and the nonfibrous matter is removed while the marked area still forms part of a larger sample and the threads cannot, therefore, be lost from it. lithe amount of non-fibrous matter is to be determined, it is stipulated that the larger sample shall be a square cut with its diagonals parallel to the directions of the threads in the fabric, lithe amount of non-fibrous matter has not to be determined, the larger sample may be of any shape or size.
Method B: A specimen of known area is dissected and the non-fibrous matter is removed from the warp and welt threads.
5.1 Indelible marking Ink.
Determine the mass of the marked area to an accuracy of 0,1 %.
Working over paper of a colour suitable for showing up fragments of the yarn and fibre from the fabric being tested, fray out from one edge of the square or rectangle, and collect together the threads more easily removed from the fabric.
From time to time, cut off the fringe of threads remaining in the other direction of the fabric and collect the short lengths together, keeping them separate from the more easily removed threads. When the whole of the marked area has been dissected into warp and welt threads, determine the mass of the two sets of threads separately to an accuracy of 0,1 %. The sum of these two masses shall not differ from the mass of the fabric before dissection by more than 1 %. Where the sum of the masses of warp and welt threads differs by more than 1 % from the mass of the fabric specimen. the procedure has not been followed with sufficient accuracy. Repeat the procedure in order to achieve the required accuracy.
Long rectangular specimens are easier to dissect than squares, but the dissection of the latter may be facilitated by cutting into several rectangles with their lengths in the direction of the threads more easily removed from the fabric.
8.2 Method B
Dissect the specimen of known area into warp and weft threads over paper of a colour suitable for showing up fragments of yarn from the fabric being tested. When the dissection of the specimen has been completed, remove the non-fibrous matter from the two sets of threads separately by a method described in ISO 1833-1. taking care that no loss of fibre occurs during the process.
Dry the threads and bring them into equilibrium with the standard atmosphere for testing, from the dry side by exposing them freely to that atmosphere. Determine the mass of the two sets of threads separately to an accuracy of 0,1 %.BS ISO 7211-6 pdf download.