ASTM D7642-12(2020)
(Practice)Standard Practice for Establishment of Calibration Cottons for Cotton Classification Instruments
Standard Practice for Establishment of Calibration Cottons for Cotton Classification Instruments
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 1: Benchmark 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.
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, 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.
General Information
Relations
Standards Content (Sample)
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.
Designation:D7642 −12 (Reapproved 2020)
Standard Practice for
Establishment of Calibration Cottons for Cotton
Classification Instruments
This standard is issued under the fixed designation D7642; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.1 This practice provides instructions for the development
Barriers to Trade (TBT) Committee.
of calibration cotton standards by establishing cotton fiber
values for micronaire, length, uniformity index, and strength.
2. Referenced Documents
The purpose of calibration cotton standards is for calibration of
2.1 ASTM Standards:
cotton classification instruments to the level of the internation-
D123 Terminology Relating to Textiles
ally recognized United States Department of Agriculture
D7139 Terminology for Cotton Fibers
(USDA) Benchmark Reference Cotton Standards. The USDA
D7410 Practice for Qualification of Cotton Classification
has established calibration cotton standards for domestic up-
Instruments for Cotton Marketing
land and Extra Long Staple (ELS) cottons and this practice
provides an instruction for other geographical regions to
3. Terminology
establish their own calibration cotton standards for cotton
3.1 For all the terminology related to D13.11, refer to
classification instruments.
Terminology D7139.
1.2 This practice shall be used for the establishment of
3.1.1 The following terms are relevant to this standard:
calibration cottons for the testing of Upland and ELS cottons.
calibration cotton standards, candidate bale, Extra Long Staple
1.3 Only saw ginned cottons shall be used in this practice. Cotton, fanhead, fanheading, length, ringer cotton, roller
ginned cotton, saw ginned cotton, strength, Universal mi-
Roller gin cottons are not valid for use due to higher measure-
ment variability. cronaire calibration cotton standards, USDA benchmark refer-
ence cotton standard, value setting, value setting group, value
1.4 The calibration cotton established by this practice is not
setting subgroup.
valid for use as a micronaire calibration standard. The mi-
cronaire standard value is not for the instrument calibration of 3.2 For definitions of all other textile terms seeTerminology
D123.
the micronaire module; it is utilized by the instrument for the
correction of the strength measurement during the calibration
4. Summary of Practice
routine.
4.1 In order to establish calibration cotton standards for use
1.5 Thevaluesstatedininch-poundaretoberegardedasthe
in calibration of cotton classification instruments, testing shall
standard. The values given in parentheses are mathematical
be performed on samples from each candidate bale while being
conversions to SI units that are provided for information only.
tested in conjunction with benchmark cottons and ringer
1.6 This standard does not purport to address all of the
cottons. The samples shall be tested in a minimum of four
safety concerns, if any, associated with its use. It is the
laboratories and on a minimum of six cotton classification
responsibility of the user of this standard to establish appro-
instruments. Established values are calculated based on the
priate safety, health, and environmental practices and deter-
level of the benchmark cottons.
mine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accor- 5. Significance and Use
dance with internationally recognized principles on standard-
5.1 The purpose of this practice is to provide standardiza-
ization established in the Decision on Principles for the
tion in the value setting of calibration cotton standards to be
used for cotton classification instrument calibration.
This test method is under the jurisdiction ofASTM Committee D13 on Textiles
and is the direct responsibility of Subcommittee D13.11 on Cotton Fibers. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved July 1, 2020. Published August 2020. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2012. Last previous edition approved in 2012 as E7642-12. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D7642-12R20 the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7642−12 (2020)
5.2 The practice provides procedures for the value setting 7.1.1 Candidate bales shall be saw-ginned. Ginning shall
for calibration cotton standards. These procedures are for use take place a minimum of one calendar year prior to being
by cotton fiber testing organizations that establish standard included in a value setting group.
values on candidate bales that will be utilized as calibration
7.1.2 Candidate bales for short/weak and long/strong cali-
cotton standards for cotton classification instruments on the
bration cottons are selected according to Table 1.
level of the benchmark cottons.
7.1.3 Atotal of ten (10) samples shall be removed from ten
NOTE 1—Benchmark cottons are of high value and of limited supply.
(10) equally spaced positions across the fanheaded candidate
Long term accuracy and stability of the internationally recognized USDA
bale (see Fig. 1). Ensure each sample is no less than 4 lb (2000
cotton standards are dependent on long term maintenance of the bench-
g) or 1 lb (450 g) times the number of laboratories.
mark cottons. Therefore, distribution of the benchmark cottons will be
tightly controlled by the USDA.
7.2 A value setting group also includes a total of ten (10)
samples of cotton for each designated benchmark and ringer
6. Apparatus and Materials
cotton.
6.1 Cotton classification instruments with a fully automated
7.2.1 Benchmark and ringer samples shall be obtained from
comb sampling device.
USDA, AMS, Cotton Division.
6.1.1 A minimum of six (6) total cotton classification
7.2.2 Ten (10) samples of cotton for each designated bench-
instruments from a minimum of four (4) total laboratories shall
mark and ringer cotton shall be subdivided into the number of
be utilized in value setting. One (1) USDAcotton classification
value setting subgroups to be prepared (minimum of 4). Ensure
instrument from one (1) USDAlaboratory shall be included as
that each subdivided sample is a minimum of 1 lb (450 g).
part of the total instruments and laboratories.
7.3 Assign the sample identification numbers such that the
6.1.2 The cotton classification instruments shall adhere to
sample identification is associated with the bale number and
the requirements of Practice D7410 for the qualification of
the location within the fanheaded bale. SeeAttachment 1 as an
cotton classification instruments. Each instrument to be in-
example.
cluded in value setting shall successfully complete the quali-
fication process within one month prior to testing. If multiple
7.3.1 Subdivide the ten samples taken from each bale into
value settings will be performed, the instrument qualification the number of value setting subgroups to be prepared (mini-
process shall be successfully completed on a six-month basis
mum of 4). Ensure that each subdivided sample is a minimum
during value settings. of 1 lb (450 g).
6.2 Benchmark cotton (short/weak), with established values
7.4 Distribute the value setting subgroups to the laborato-
for length, uniformity index, strength and micronaire.
ries.An additional 1 lb (450 g) of each benchmark cotton shall
be included in each subgroup for calibration of the cotton
6.3 Benchmarkcotton(long/strong),withestablishedvalues
classification instruments.
for length, uniformity index, strength and micronaire.
6.4 Ringer cotton (short/weak), with established values for
8. Conditioning
length, uniformity index, strength and micronaire.
8.1 Standard atmospheric conditions shall be maintained in
6.5 Ringer cotton (long/strong), with established values for
eachlaboratoryat21 61°C(70 62°F)and65 62%relative
length, uniformity index, strength and micronaire.
humidity.
6.6 Candidate bales (up to 18), saw-ginned cotton with
8.1.1 Condition each value setting subgroup for a minimum
targeted measurement ranges for micronaire, length, unifor-
of 72 h prior to testing according to 8.1.
mity index and strength as given in 7.1.2.
9. Procedure
7. Sampling
9.1 Arrange the individual samples of the value setting
7.1 Value setting begins by obtaining test samples from a
subgroup in numerical order.
maximum of twenty-two (22) bales. Samples from one bench-
mark cotton (short/weak), one benchmark cotton (long/str
...
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