ASTM D7642 - 12

    Standard Practice for Establishment of Calibration Cottons for Cotton Classification Instruments

    Active Standard ASTM D7642 | Developed by Subcommittee: D13.11

    Book of Standards Volume: 07.02


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    Significance and Use

    5.1 The purpose of this practice is to provide standardization in the value setting of calibration cotton standards to be used for cotton classification instrument calibration.

    5.2 The practice provides procedures for the value setting for calibration cotton standards. These procedures are for use by cotton fiber testing organizations that establish standard values on candidate bales that will be utilized as calibration cotton standards for cotton classification instruments on the level of the benchmark cottons.

    Note 1Benchmark cottons are of high value and of limited supply. Long term accuracy and stability of the internationally recognized USDA cotton standards are dependent on long term maintenance of the benchmark cottons. Therefore, distribution of the benchmark cottons will be tightly controlled by the USDA.

    1. Scope

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


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D123 Terminology Relating to Textiles

    D7139 Terminology for Cotton Fibers

    D7410 Practice for Qualification of Cotton Classification Instruments for Cotton Marketing


    ICS Code

    ICS Number Code 59.060.10 (Natural fibres)

    UNSPSC Code

    UNSPSC Code 11151507(Cotton fibers)


    Referencing This Standard

    DOI: 10.1520/D7642-12

    ASTM International is a member of CrossRef.

    Citation Format

    ASTM D7642-12, Standard Practice for Establishment of Calibration Cottons for Cotton Classification Instruments, ASTM International, West Conshohocken, PA, 2012, www.astm.org

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