ASTM D2494-13(R2020) pdf free download

ASTM D2494-13(R2020) pdf free download.Standard Test Method for Commercial Mass of a Shipment of Yarn or Manufactured Staple Fiber or Tow
1. Scope
1.1 This test method provides a measurement of the com- mercial 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). N OTE 1—For other test methods for measuring mass of fibrous materials, refer to Practice D2720. 1.1.1 Sampling in this test method is primarily for use in acceptance testing rather than production control. manufac- tured fiber producers usually sample for the commercial “mass” of product on an on-going basis rather than each shipment to a customer. 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 commer- cial 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. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.5 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Summary of Test Method
4.1 Representative specimens from a shipment are dried, weighed, and, in some cases, scoured and weighed again. From the net mass of the shipment and the masses of the specimens before and after treatment, commercial mass ofthe shipment is calculated using one of the following options: 4.1.1 Option I—CAS basis treatment consists of scouring and drying. Commercial mass includes a correction for com- mercial allowance. 4.1.2 Option II—CMRS basis treatment consists ofscouring and drying. Commercial mass excludes scourables but includes a correction for commercial moisture regain. 4.1.3 Option III—CMRU basis treatment consists of drying only. Commercial mass includes finishes and a correction for commercial moisture regain. 4.1.4 Option IV—UN basis requires no samples and no treatment. Commercial mass equals the net mass of the shipment without adjustment for scourables or moisture.
5. Significance and Use
5.1 This test method is considered satisfactory as a referee method for acceptance testing ofcommercial shipments ofyarn or manufactured staple fibers. 5.1.1 If there are differences of practical significance be- tween 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 com- parative test that are as homogeneous as possible, drawn from the same lot ofmaterial 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 labora- tories 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.