Significance and Use
This test method for determining micronaire reading of cotton fibers is considered satisfactory for acceptance testing of commercial shipments when the levels are controlled by use of a full range of calibration cotton standards.
5.1.1 In case of a dispute arising from differences in reported test results when using this test method 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. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the two parties should take a group of test specimens that are as homogeneous as possible and that are from a lot of material of the type 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 Student’t-test for unpaired data and an acceptable probability level chosen by the two parties before the testing is begun. If a bias is found, either its cause must be found and corrected or the purchaser and the supplier must agree to interpret future test results in the light of the known bias.
The micronaire reading of cotton fibers is a function of both fineness and maturity and is related to mill processing performance and to the quality of the end products. Factors correlated with micronaire reading include cleaning efficiency, neppiness, and the strength and uniformity of the yarn.
Note 2—A modification of this test method is used in commercial trading to select bales which will conform to contract guarantees for specified micronaire readings. For this purpose, it is usual practice to test only one specimen per sample.
1.1 This test method covers the determination of the micronaire reading of loose cotton fibers by measuring the resistance of a plug of cotton fibers to air flow under prescribed conditions. Note 1For other methods for determining the fineness of fibers based on the air-flow principle, refer to Test Method D 1449, Test Method for Specific Area and Immaturity Ratio of Cotton Fibers (Arealometer Method), and to Test Method D 1282, Test Method for Resistance to Air Flow as an Indication of Average Fiber Diameter of Wool Top, Card Sliver, and Scoured Wool.
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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.