Active Standard ASTM D2494 | Developed by Subcommittee: D13.58
Book of Standards Volume: 07.01
Historical (view previous versions of standard)
Significance and Use
5.1.1 If there are differences of practical significance between reported test results for two laboratories (or more), comparative tests should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, use the samples for such a comparative test that are as homogeneous as possible, drawn from the same lot of material as the samples that resulted in disparate results during initial testing and randomly assigned in equal numbers to each laboratory. The test results from the laboratories involved should be compared using a statistical test for unpaired data, a probability level chosen prior to the testing series. If a bias is found, either its casuse must be found and corrected, or future test results for that material must be adjusted in consideration of the known bias.
5.2 Option I is in common use in other countries, particularly in Europe.4
5.3 Option II is used to calculate the commercial mass of as-produced manufactured filament yarns (except some producer-textured yarns), manufactured staple fibers, and tows. This option is intended to reflect the mass of fiber remaining after fiber lubricants and processing aids are removed.
5.4 Option III is used to calculate the commercial mass of spun yarns, textured yarns, tops, and slivers. When materials are sold on a CMRU basis, the purchaser pays for the fiber lubricant or other removable processing aids.
5.6 When it can be shown that solvent extraction or another method of testing gives the same results, or results that have a constant ratio to those obtained by the scour procedure, that method may be used for routine testing of known production but should not be substituted for a scour on new or unknown material. For the determination of extractable matter, refer to Test Method D2257.
5.7 Under certain circumstances, samples taken from yarns and manufactured staple fibers and tows can change moisture content rapidly. For this reason, very careful planning and handling of samples are required to prevent major biases in commercial mass results.
1.1 This test method provides a measurement of the commercial mass of a shipment of yarn or manufactured staple fiber or tow. This test method applies to (1) yarn of all fiber types except silk, glass, asbestos, and bast; (2) tops and slivers of all fiber types except wool, silk, glass, asbestos, and bast; and (3) manufactured fibers or tow, except glass and other fibers used for special purposes such as flock (Note 1).
1.2 Commercial mass has been traditionally based on one of three options depending on the state of the material: (1) dried, unscoured yarn, staple fiber, tow, and so forth, using commercial moisture regain in the calculations; (2) dried, scoured yarn, staple fiber, tow, and so forth, using commercial moisture regain values in the calculations; and (3) dried, scoured yarn, staple fiber, tow, and so forth, using a defined allowance in the calculations.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D123 Terminology Relating to Textiles
D629 Test Methods for Quantitative Analysis of Textiles
D1909 Standard Table of Commercial Moisture Regains for Textile Fibers
D2257 Test Method for Extractable Matter in Textiles
D2258 Practice for Sampling Yarn for Testing
D2720 Practice for Calculation of Commercial Weight and Yield of Scoured Wool, Top, and Noil for Various Commercial Compositions
D3333 Practice for Sampling Manufactured Staple Fibers, Sliver, or Tow for Testing
D4849 Terminology Related to Yarns and Fibers
AATCC Standard150 Dimensional Changes in Automatic Home Laundering of Woven Garments Available from the American Association of Textile Chemists and Colorists, P.O. Box 12215, Research Triangle Park, NC 27709.
ICS Number Code 59.080.20 (Yarns)