ISO 7211-6:2020 pdf download – Textiles —Methods for analysis ofwoven fabrics construction —Part 6: Determination of the mass of warp and weft per unit area of fabric
ISO 7211-6:2020 pdf download – Textiles —Methods for analysis ofwoven fabrics construction —Part 6: Determination of the mass of warp and weft per unit area of fabric.
5.3 Dissection needle.
5.4 Small template. Template to mark (or a die to cut) a square or a rectangle of known area of not less than 150 cm2. The length to width ratio of the rectangle shall not exceed 4.
5.5 Large template. Template to mark (or a die to cut) a square which is sufficiently large to enclose the area marked with the smaller template (SA) when placed with its diagonals parallel to the sides of the enclosed square or rectangle.
5.6 Balance, accurate to 0.1 % of the smallest quantity to be weighed.
6 Conditioning and testing atmosphere
The standard atmospheres for pre-conditioning, conditioning and testing textiles specified in ISO 139 shall he used.
7 Test specimens
Before marking or cutting, expose the samples from which the test specimens will be removed to the standard atmosphere for conditioning until It Is In equilibrium with that atmosphere.
Take the specimens from each sample.
7.2 Method A
With the aid of the large template (55). mark in pencil on the sample a square with its diagonals in the direction of the warp and welt threads. In the centre of the square, and with the aid of the small template (SA). mark in indelible ink (Sd) a square or rectangle with Its sides In the directions of the warp and weft threads. Cut the larger square from the sample by means of the scissors (52) and identify the warp and weft directions. Alternatively, remove the larger square from the sample by means of a die.
When the amount of non-fibrous matter has not to be determined, the larger specimen may be of any shape or size, provided that the threads are retained in the inner marked area during the removal of added matter.
7.3 Method B
With the aid of the small template (SA). mark in pencil a square or a rectangle with its sides as closely as possible parallel to the warp and weft threads. Cut the square or rectangle from the fabric by means of the scissors (52) and identify the warp and welt directions. Alternatively, remove a square of the appropriate size From the fabric by means of a die.
Determine the mass of the marked area to an accuracy olO,1 %.
Working over paper ala 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 I %. 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 %.
9 Calculation and expression of results
From the conditioned masses of warp and welt, free from added matter, and the known area of the specimens dissected, calculate the mass per unit area of warp, welt and fabric and express each in grams per square metre.
10 Test report
The test report shall include at least the following particulars:
a) a reference to this document (I.e. ISO 7211.6:2020);
b) atmosphere used (standard or one of the alternative atmospheres);
c) actual method used, i.e. method A or method B;
d) method used for removal of non-fibrous matter, Ilcarried out;
e) the mass olwarp and welt per unit area of each specimen and. if required. the mass per unit area o the fabric, all expressed In grams per square metre;
f) details of any deviation from the given procedure;
g) any unusual features observed;
h) date of the test.