ASTM D1440-07(2019)

Standard Test Method for Length and Length Distribution of Cotton Fibers (Array Method)

SIGNIFICANCE AND USE
5.1 The array method provides objective measurements for determining the fiber length and length distribution in a sample of cotton. The results can be plotted to show the length-weight distribution of all the fibers in the sample. Data obtained from array tests are useful in fiber length research studies, for investigation of changes in fiber length distribution in ginning and mill processing, and for other research purposes.  
5.2 Upper quartile length is correlated with, but usually longer than, Fibrograph and 2.5 % span length as defined in Test Method D1447. Judgment must be used in making comparisons between length measures from arrays and measures obtained by other methods, which may be basically different.  
5.3 The coefficient of length variation is a measure of length distribution, or nonuniformity of length. Because the fiber weight-length distribution is usually highly skewed, statistical judgments based on the assumption of normality are not justified.
FIG. 1 Combs and Accessories for Arraying Fibers According to Length  
a and c—Banks of combs.
b—Forceps, tips padded with hard leather, for transferring fibers from one set of combs to the other.
d—Depressor for placing fibers in combs.
f—Dissecting needle.
g—Fork for scooping up fiber groups off velvet surface.
h—Aluminum plate covered with velvet cloth.
i—Special rule for measuring length of fiber groups.
k—Smooth plate for placing fibers onto velvet surfaces.
l—Wire rack for holding fiber groups wrapped in papers.
m—Smooth pointed tweezers.
n—Lift for raising combs in place.
o—Rack for holding velvet-covered boards.
p—Velvet-covered boards on which several pulls have been arrayed.
Note 1: Other accessories required for length arraying, not shown above, consist of the following: small whisk broom for cleaning velvet surfaces, one pair of tweezers with smooth round tips, forceps similar to b but having tips padded with rubber for laying groups on velvet surfaces, small pap...
SCOPE
1.1 This test method covers the determination of the fiber length and length distribution in loose cotton fibers.
Note 1: For another method for measuring fiber length, see Test Method D1447.  
1.2 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.  
1.3 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

• Status: Published
• Publication Date: 30-Jun-2019
• ICS: 59.060.10 - Natural fibres
• Technical Committee: D13 - Textiles
• Drafting Committee: D13.11 - Cotton Fibers

Relations

• Replaces: ASTM D1440-07(2012) - Standard Test Method for Length and Length Distribution of Cotton Fibers (Array Method)
• Effective Date: 01-Jul-2019
• Refers: ASTM D123-17 - Standard Terminology Relating to Textiles
• Effective Date: 01-Mar-2017
• Refers: ASTM D123-15b - Standard Terminology Relating to Textiles
• Effective Date: 15-Sep-2015
• Refers: ASTM D123-15a - Standard Terminology Relating to Textiles
• Effective Date: 01-Sep-2015
• Refers: ASTM D123-15 - Standard Terminology Relating to Textiles
• Effective Date: 01-Apr-2015
• Refers: ASTM D7139-09(2013) - Standard Terminology for Cotton Fibers
• Effective Date: 01-Jul-2013
• Refers: ASTM D123-13a - Standard Terminology Relating to Textiles
• Effective Date: 15-Jun-2013
• Refers: ASTM D123-13ae1 - Standard Terminology Relating to Textiles
• Effective Date: 15-Jun-2013
• Refers: ASTM D123-13 - Standard Terminology Relating to Textiles
• Effective Date: 15-May-2013
• Refers: ASTM D1441-12 - Standard Practice for Sampling Cotton Fibers for Testing
• Effective Date: 01-Jul-2012
• Refers: ASTM D123-12e1 - Standard Terminology Relating to Textiles
• Effective Date: 01-Feb-2012
• Refers: ASTM D123-12 - Standard Terminology Relating to Textiles
• Effective Date: 01-Feb-2012
• Refers: ASTM D123-09e1 - Standard Terminology Relating to Textiles
• Effective Date: 15-Jan-2009
• Refers: ASTM D123-09 - Standard Terminology Relating to Textiles
• Effective Date: 15-Jan-2009
• Refers: ASTM D7139-09e1 - Standard Terminology for Cotton Fibers
• Effective Date: 15-Jan-2009

Overview

ASTM D1440-07(2019), published by ASTM International, is the Standard Test Method for Length and Length Distribution of Cotton Fibers (Array Method). This international standard describes an objective method for determining both the length and length distribution in loose cotton fibers using the array method, involving mechanical separation and organization of fibers. Data generated through this method are useful for quality control, research studies on cotton fiber properties, and for evaluating the impact of textile processing (such as ginning and mill processing) on cotton fiber length and distribution.

Key Topics

• Objective Measurement: The array method provides repeatable, precise measurements of fiber length and length distribution in cotton samples.
• Length-Weight Distribution: The process allows for plotting the length-weight distribution of fibers, offering insight into cotton quality and uniformity.
• Upper Quartile Length and Coefficient of Variation: Key results include upper quartile length, mean length, and coefficient of length variation, which measure fiber uniformity and quality.
• Physical Arraying: The method physically separates fibers of different lengths, using combs, forceps, velvet boards, and other accessories to create organized arrays for measurement.
• Statistical Sensitivity: The coefficient of length variation gives a measure of nonuniformity, while also acknowledging that fiber distribution is often not normally distributed, warranting careful statistical judgement.

Applications

• Cotton Fiber Quality Research: Data from ASTM D1440 are essential for researchers investigating fiber properties, varietal performance, and process-induced changes in cotton length during ginning and textile manufacturing.
• Benchmarking and Method Comparison: The array method serves as a standard for comparison with other fiber length measurement techniques such as Fibrograph or span length methods (including ASTM D1447). It acts as a reference to judge precision and accuracy.
• Process Optimization in Textile Manufacturing: By monitoring fiber length distribution before and after processing, manufacturers can evaluate and control the impact of mechanical operations on cotton fiber quality.
• Calibration and Standardization: Standard cotton samples and the use of defined sampling and conditioning practices ensure consistency and reproducibility of results across laboratories.

Related Standards

• ASTM D123: Terminology Relating to Textiles - Provides standard definitions for terms used in textile testing.
• ASTM D1441: Practice for Sampling Cotton Fibers for Testing - Specifies sampling methods for reliable analysis.
• ASTM D1447: Test Method for Length and Length Uniformity of Cotton Fibers by Photoelectric Measurement - Offers an alternative, photoelectric-based technique for fiber length analysis.
• ASTM D1776: Practice for Conditioning and Testing Textiles - Covers procedures for conditioning samples to ensure environmental consistency during testing.
• ASTM D7139: Terminology for Cotton Fibers - Details specific terminology for cotton fiber tests and classification.

Practical Value

• Quality Control: Ensures reliable measurement of cotton fiber length and distribution, supporting textile quality assurance efforts.
• Industry Alignment: Developed following globally accepted international standardization principles, facilitating international trade and regulatory compliance.
• Accuracy and Reproducibility: Recognized as one of the most accurate available methods for physical measurement of cotton fiber length, serving as a reference point for evaluating other length measurement techniques.
• Research and Development: Enables innovation in cotton processing and textile engineering by providing foundational data on fiber properties essential for process improvements and new product development.

Keywords

cotton fiber length, array method, ASTM D1440, cotton fiber length distribution, textile testing standards, fiber quality, cotton research, textile manufacturing, fiber length uniformity, cotton length measurement

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: D1440 − 07 (Reapproved 2019)
Standard Test Method for
Length and Length Distribution of Cotton Fibers (Array
Method)
This standard is issued under the fixed designation D1440; 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 3.2 For all other terminology related to textiles see Termi-
nology D123.
1.1 This test method covers the determination of the fiber
length and length distribution in loose cotton fibers.
4. Summary of Test Method
NOTE 1—For another method for measuring fiber length, see Test
Method D1447. 4.1 A sorting apparatus consisting of two banks of parallel
combs is used to straighten and align the fibers in a 75-mg test
1.2 This standard does not purport to address all of the
specimen. The fibers are pulled from one bank of combs and
safety concerns, if any, associated with its use. It is the
transferred to the other in such a manner that one end of each
responsibility of the user of this standard to establish appro-
fiber is aligned with the base comb. The transfer is repeated to
priate safety, health, and environmental practices and deter-
straighten the other ends of the fibers. As the fibers are
mine the applicability of regulatory limitations prior to use.
withdrawn from the combs for the third time, they are placed
1.3 This international standard was developed in accor-
in order of length on velvet covered boards. The pulls are
dance with internationally recognized principles on standard-
measured, and those that fall within each length interval are
ization established in the Decision on Principles for the
collected and weighed. From these weight-length data, the
Development of International Standards, Guides and Recom-
upper quartile length, mean length, and coefficient of length
mendations issued by the World Trade Organization Technical
variation are calculated.
Barriers to Trade (TBT) Committee.
5. Significance and Use
2. Referenced Documents
2.1 ASTM Standards:
5.1 The array method provides objective measurements for
D123 Terminology Relating to Textiles
determining the fiber length and length distribution in a sample
D1441 Practice for Sampling Cotton Fibers for Testing
of cotton. The results can be plotted to show the length-weight
D1447 Test Method for Length and Length Uniformity of
distribution of all the fibers in the sample. Data obtained from
Cotton Fibers by Photoelectric Measurement
array tests are useful in fiber length research studies, for
D1776 Practice for Conditioning and Testing Textiles
investigation of changes in fiber length distribution in ginning
D7139 Terminology for Cotton Fibers
and mill processing, and for other research purposes.
5.2 Upper quartile length is correlated with, but usually
3. Terminology
longer than, Fibrograph and 2.5 % span length as defined in
3.1 ForallterminologyrelatedtoD13.11,CottonFibers,see
Test Method D1447. Judgment must be used in making
Terminology D7139.
comparisons between length measures from arrays and mea-
3.1.1 The following terms are relevant to this standard:
sures obtained by other methods, which may be basically
coefficient of variation, length group, length interval, mean
different.
length, pull, upper quartile length.
5.3 The coefficient of length variation is a measure of length
distribution, or nonuniformity of length. Because the fiber
weight-length distribution is usually highly skewed, statistical
This test method is under the jurisdiction ofASTM Committee D13 on Textiles
and is the direct responsibility of Subcommittee D13.11 on Cotton Fibers. judgments based on the assumption of normality are not
Current edition approved July 1, 2019. Published July 2019. Originally approved
justified.
in 1955. Last previous edition approved in 2012 as D1440 – 07 (2012). DOI:
10.1520/D1440-07R19.
5.4 The array method makes a physical separation of fibers
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
of different lengths. It therefore serves as a standard, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
benchmark, with which other methods may be compared and
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. by which their precision and accuracy may be judged.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1440 − 07 (2019)
a and c—Banks of combs.
b—Forceps, tips padded with hard leather, for transferring fibers from one set of combs to the other.
d—Depressor for placing fibers in combs.
f—Dissecting needle.
g—Fork for scooping up fiber groups off velvet surface.
h—Aluminum plate covered with velvet cloth.
i—Special rule for measuring length of fiber groups.
k—Smooth plate for placing fibers onto velvet surfaces.
l—Wire rack for holding fiber groups wrapped in papers.
m—Smooth pointed tweezers.
n—Lift for raising combs in place.
o—Rack for holding velvet-covered boards.
p—Velvet-covered boards on which several pulls have been arrayed.
NOTE 1—Other accessories required for length arraying, not shown above, consist of the following: small whisk broom for cleaning velvet surfaces,
one pair of tweezers with smooth round tips, forceps similar to b but having tips padded with rubber for laying groups on velvet surfaces, small papers
1 1 1
for wrapping groups of fibers (papers 2 ⁄2 by 3 in. (62 by 75 mm)) with small envelopes for them (2 ⁄2 by 4 ⁄4 in. (62 by 110 mm)), and balances having
ranges from 0 to 25 mg and 0 to 100 mg.
FIG. 1 Combs and Accessories for Arraying Fibers According to Length
5.5 Test Method D1440 for testing length and length distri- 6.5 Secondary Standard Cotton—Lots of cotton the length
bution of cotton fibers (array method) is not commonly used of which has been established by extensive comparisons with
for acceptance testing of commercial shipments. USDA standards.
6. Apparatus and Materials
7. Sampling
6.1 Double Bank Sorter, and equipment as illustrated in Fig.
7.1 Prepare the laboratory sample as directed in Practice
1. The method outlined here is especially adapted to the
D1441. Take either two or three subsamples depending on the
Suter-Webb Duplex Cotton Fiber Sorter, but the procedure
precision desired. Take subsamples that weigh approximately
may be carried out with other similar apparatus with more or
80 mg each for use in preparing the test specimen in one of the
less obvious alterations.
following manners:
6.2 Balance, with a capacity of at least 25 mg and a 7.1.1 From a hand sliver, carefully separate a 2-in. (50-mm)
sensitivity of 60.05 mg. length of the sliver for each subsample.
7.1.2 From a mechanically blended 3-g sliver, separate 2-in.
6.3 Balance, with a capacity of at least 100 mg and a
(50-mm) subsamples.
sensitivity of 60.1 mg.
7.1.3 From a mechanically blended 10-g sliver, pull out of
6.4 Standard Calibration Cotton Samples, for the calibra-
themiddleofthesampleasubsampleabout2in.(50mm)long,
tion of array length measurements.
extending through its whole thickness, and wide enough to
weigh approximately 80 mg. Take subsamples from near the
NOTE 2—Standard calibration cotton samples are available from the
Cotton Division, Agricultural Marketing Service, U.S. Department of
beginning, midway, and near the end of the sliver.
Agriculture, 3275 Appling Rd., Memphis, TN 38133.
7.2 If the laboratory samples have not been in the standard
atmosphere for at least 2 h before the preparation of
The sole source of supply of the apparatus known to the committee at this time
subsamples, bring the subsamples to approximate equilibrium
is the Alfred Suter Co., New York, NY. If you are aware of alternative suppliers,
with the standard atmosphere for testing before preparing
pleaseprovidethisinformationtoASTMHeadquarters.Yourcommentswillreceive
specimens. Exposure to moving air in the laboratory for2his
careful consideration at a meeting of the responsible technical committee, which
you may attend. sufficient.
D1440 − 07 (2019)
8. Preparation of Test Specimen 10.4.1 Place the test specimen in the left bank of combs
perpendicular to and approximately in the center of the combs.
8.1 Prepare one specimen from each of the three sub-
Using the depressor (Fig. 1, d), depress the test specimen at
samples. Gently parallelize the fibers by hand. Remove all
least ⁄16 in. (2 mm) below the tips of the comb teeth, but no
foreign matter, but do not discard any fibers.
lower than half the length of the teeth. The comb fork can be
8.2 Separate from each subsample, by longitudinal division,
used to raise any fibers that are depressed below this level.
a portion weighing approximately 76 mg. If the specimen
10.4.2 Drop front combs of the left bank until a smaller
weighs more than 77 mg, reduce its weight by removing a
number of fibers protrude beyond the comb nearest the
small group of fibers from the side of the specimen. If the
operator.
specimen weighs less than 75 mg, add a small group of fibers
10.4.3 Griptheendsofafewofthesefiberswiththeforceps
taken from the side of the subsample. Never remove fibers
(Fig. 1, b) and withdraw them from the combs with a smooth
from either the specimen or subsample by pulling from the
horizontal motion.
ends, as this tends to remove the longest fibers.After adjusting
10.4.4 Continue holding the fiber ends with the forceps.
the specimen weight to approximately 76 mg, condition the
Place the forceps at the farther edge of the right bank of combs
specimen and the remaining portion of the subsample in
and draw the fibers carefully through the combs until the edge
accordance with Section 9.
of the forceps is just touching the near edge of the first comb.
Release the fibers from the forceps. With the depressor, push
9. Conditioning
the fibers down for a short distance into the teeth of the combs.
9.1 Practice D1776 covers the conditioning of textiles for
Repeat this procedure until the transfer of all protruding fibers
testing. If the laboratory samples have a moisture content of
is complete.The fibers should not protrude more than ⁄16 in. (2
10 % or higher, Practice D1776 should be used to condition the
mm) beyond the nearer comb of the right bank.
samples for testing. For samples below 10 % moisture content,
10.4.5 Drop an additional comb of the left bank and
the conditioning procedure outlined in 9.2 and 9.3 is consid-
continuetransferringthefibers.Donotwithdrawinonepullall
ered adequate for length testing by this test method.
of the fibers protruding from a comb, but take four or more
separate pulls, withdrawing in each pull those fibers which
9.2 If the laboratory samples have not been in the standard
protrude farthest.The width of the specimen placed in the right
atmosphere for at least 2 h before the preparation of the
comb bank should be no greater than the width of the forceps
subsample, bring the subsamples to approximate equilibrium
being used.
with the standard atmosphere for testing before preparing
10.4.6 Continue the transferring procedure, dropping combs
specimens. Exposure to moving air in the laboratory for4his
as necessary, until all the fibers have been transferred from the
sufficient.
left to the right set of combs.
9.3 After the specimens have been prepared, condition them
10.4.7 Using the dissecting needle (Fig. 1, f ), gently un-
in the standard atmosphere for testing. Exposure to moving air
tangle the fiber ends extending beyond the front comb. With
in the standard atmosphere for a minimum period of2his
the forceps, pull out any fibers that extend more than approxi
...