Standard Test Method for Linear Density of Yarn (Yarn Number) by the Skein Method

Importancia y uso:

5.1 Test Method D1907/D1907M is considered satisfactory for acceptance testing of commercial shipments, since it has been used extensively in the trade for that purpose.

5.1.1 In case of dispute arising from differences in reported test results when using Test Method D1907/D1907M for acceptance testing of commercial shipments, the purchaser and the supplier should conduct comparative tests to determine if there is a statistical bias between their laboratories.

5.1.2 Competent statistical assistance is recommended for the determination of such a bias. As a minimum, the two parties should take a group of test specimens that are as homogeneous as possible, and that are from the same lot of the material in question. The test specimens should then be randomly assigned in equal numbers to each laboratory for testing. The average results from the two laboratories should be compared using statistical analysis for unpaired data, and an acceptable probability level chosen by the parties before testing begins. If a bias is found, either its cause must be identified and corrected, or the purchaser and supplier must agree to interpret future test results for that material with consideration to the known bias.

5.2 This test method is intended primarily for the determination of the average linear density of yarns. However, the variations identified by the results may also provide useful information. If the coefficient of variation is to be calculated, each skein must be weighed separately, and a larger number of skeins will need to be tested (as compared to the number of skeins to be tested for the determination of the average yarn linear density alone).

5.3 This test method includes seven options, depending on whether the yarn is scoured before weighing, weighed in the conditioned or oven-dried state, or whether or not the results obtained are adjusted for commercial moisture regain, or a commercial allowance. Option 1 (unscoured, conditioned yarn) is generally used for yarns spun on the cotton system, while Options 6 and 7 (scoured, oven dried yarn, plus commercial moisture regain, or allowance) are generally used for filament yarns, or yarns containing wool fibers. The specific options to be used in any instance shall be agreed upon by the parties, or as prescribed in test methods or tolerances.

5.4 In Options 2, 3, 5, 6, and 7, an oven-dried sample is obtained by exposing the yarn in an oven with a supply of air at standard textile testing conditions, as described in 6.3.

Subcomité:

D13.58

Referida por:

D2644-12R18, D8054_D8054M-22, D0578_D0578M-23, D8448_D8448M-22, F2848-21, D2497-07R25, D2645-07R18, D8395-23, D1577-07R24E01, D0204-02R21

Volúmen:

07.01

Número ICS:

59.080.20 (Yarns)

Palabras clave:

yarn linear density, yarn number;