ASTM D7642-12(2020)

1.1 This practice provides instructions for the development of calibration cotton standards by establishing cotton fiber values for micronaire, length, uniformity index, and strength. The purpose of calibration cotton standards is for calibration of cotton classification instruments to the level of the internationally recognized United States Department of Agriculture (USDA) Benchmark Reference Cotton Standards. The USDA has established calibration cotton standards for domestic upland and Extra Long Staple (ELS) cottons and this practice provides an instruction for other geographical regions to establish their own calibration cotton standards for cotton classification instruments.

1.2 This practice shall be used for the establishment of calibration cottons for the testing of Upland and ELS cottons.

1.3 Only saw ginned cottons shall be used in this practice. Roller gin cottons are not valid for use due to higher measurement variability.

1.4 The calibration cotton established by this practice is not valid for use as a micronaire calibration standard. The micronaire standard value is not for the instrument calibration of the micronaire module; it is utilized by the instrument for the correction of the strength measurement during the calibration routine.

1.5 The values stated in inch-pound are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only.

1.6 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.