ASTM D2495-07(2012)
(Test Method)Standard Test Method for Moisture in Cotton by Oven-Drying
Standard Test Method for Moisture in Cotton by Oven-Drying
SIGNIFICANCE AND USE
5.1 This test method for testing the moisture content of cotton can be used for acceptance testing of commercial shipments of lint cotton provided the between-laboratory bias is known.
5.1.1 If there are differences or practical significance between reported test results for two laboratories, or more, comparative test should be performed to determine if there is a statistical bias, using competent statistical assistance. As a minimum, use test samples as homogeneous as possible, drawn from the material from which the disparate test results are obtained, and assigned randomly in equal numbers to each laboratory for testing. Other materials with established test values may be used for this purpose. Compare the test results from the two laboratories using a statistical test for unpaired data at a probability level chosen prior to the testing series. If a bias is found, either its cause must be found and corrected, or future test results must be adjusted in consideration of the known bias.
5.2 Information on the moisture content of cotton is desirable since the physical properties of cotton are significantly affected by its moisture content. High moisture content increases flexibility, toughness, elongation, and tensile strength. Too high a moisture content causes difficulty in processing due to the tendency of the stock to “lap-up” on drafting rolls. Low moisture, on the other hand, facilitates cleaning but increases the brittleness of the fiber and results in fiber breakage during ginning, cleaning, and mill processing. Low moisture also increases fly waste and may cause manufacturing difficulties due to static electricity.
5.3 Variations in the amount of moisture present affect the mass and hence the market value of a lot of material sold at a definite price per unit mass. Knowledge of the moisture content or regain can be accordingly an important financial consideration.
5.4 Moisture content variation affects lap, sliver, and roving linear density which ...
SCOPE
1.1 This test method covers the determination of the amount of moisture in cotton by oven-drying and is applicable to raw cotton, cotton stock in process, and cotton waste.
1.2 This test method may also, by agreement, be used for determining moisture in blends of cotton with other fibers.
1.3 This test method offers alternative procedures for weighing the dried specimens, one procedure using an oven balance (9.3) and the other using a desiccator (9.4). Note 1—For other methods of determination of moisture in textile materials refer to Test Method D2654, which includes two options based on drying in an oven, and one option based on distillation with an immiscible solvent: Methods D885, Test Method D1576, Test Method D2462.
1.4 The values stated in SI units are to be regarded as the standard. No other units are included in this standard.
1.5 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.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D2495 − 07 (Reapproved 2012)
Standard Test Method for
Moisture in Cotton by Oven-Drying
This standard is issued under the fixed designation D2495; 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 D2654 Test Method for Moisture in Textiles (Withdrawn
1998)
1.1 Thistestmethodcoversthedeterminationoftheamount
D7139 Terminology for Cotton Fibers
of moisture in cotton by oven-drying and is applicable to raw
cotton, cotton stock in process, and cotton waste.
3. Terminology
1.2 This test method may also, by agreement, be used for
3.1 For all terminology relating to D13.11, Cotton Fibers,
determining moisture in blends of cotton with other fibers.
refer to Terminology D7139.
3.1.1 The following terms are relevant to this standard:
1.3 This test method offers alternative procedures for
cotton waste, ginned lint (cotton), lint cotton, moisture content,
weighing the dried specimens, one procedure using an oven
moisture-free,moistureregain,oven-dry,percentagepoint,raw
balance (9.3) and the other using a desiccator (9.4).
cotton, seed cotton, stock in process.
NOTE 1—For other methods of determination of moisture in textile
3.2 For all other terminology related to textiles, refer to
materials refer to Test Method D2654, which includes two options based
on drying in an oven, and one option based on distillation with an Terminology D123.
immiscible solvent: Methods D885, Test Method D1576, Test Method
D2462.
4. Summary of Test Method
1.4 The values stated in SI units are to be regarded as the
4.1 Specimens are weighed, dried in an oven, and re-
standard. No other units are included in this standard.
weighed. The difference between the original mass and the
oven-dry mass is calculated in percent, either as moisture
1.5 This standard does not purport to address all of the
content or moisture regain.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Significance and Use
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
5.1 This test method for testing the moisture content of
cotton can be used for acceptance testing of commercial
2. Referenced Documents
shipments of lint cotton provided the between-laboratory bias
is known.
2.1 ASTM Standards:
5.1.1 If there are differences or practical significance be-
D123 Terminology Relating to Textiles
tween reported test results for two laboratories, or more,
D885 Test Methods for Tire Cords, Tire Cord Fabrics, and
comparative test should be performed to determine if there is a
Industrial Filament Yarns Made from Manufactured
statistical bias, using competent statistical assistance. As a
Organic-Base Fibers
minimum,usetestsamplesashomogeneousaspossible,drawn
D1441 Practice for Sampling Cotton Fibers for Testing
from the material from which the disparate test results are
D1576 Test Method for Moisture in Wool by Oven-Drying
obtained, and assigned randomly in equal numbers to each
D2462 Test Method for Moisture in Wool by Distillation
laboratory for testing. Other materials with established test
With Toluene
values may be used for this purpose. Compare the test results
from the two laboratories using a statistical test for unpaired
data at a probability level chosen prior to the testing series. If
This test method is under the jurisdiction ofASTM Committee D13 on Textiles
a bias is found, either its cause must be found and corrected, or
and is the direct responsibility of Subcommittee D13.11 on Cotton Fibers.
future test results must be adjusted in consideration of the
Current edition approved July 1, 2012. Published August 2012. Originally
known bias.
approved in 1961 T. Last previous edition approved in 2007 as D2495–07. DOI:
10.1520/D2495-07R12.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2495 − 07 (2012)
5.2 Information on the moisture content of cotton is desir- 6.5 Desiccant—Calcium chloride is satisfactory, provided
able since the physical properties of cotton are significantly that it is redried or replaced as required for effective desicca-
affected by its moisture content. High moisture content in- tion. Any other effective, noncaustic desiccant may be used.
creases flexibility, toughness, elongation, and tensile strength. (For the desiccator procedure only, see 9.1.2 and 9.4.)
Too high a moisture content causes difficulty in processing due
6.6 Sample Containers—Metal cans, glass jars, or plastic
to the tendency of the stock to “lap-up” on drafting rolls. Low
containers of approximately 1-L (1-qt) capacity with airtight
moisture, on the other hand, facilitates cleaning but increases
covers are recommended for use when sampling cotton outside
the brittleness of the fiber and results in fiber breakage during
the laboratory.
ginning, cleaning, and mill processing. Low moisture also
NOTE 3—For very dry material, that must be weighed in the containers,
increases fly waste and may cause manufacturing difficulties
lightweight containers are desirable. For damp cotton, which would rust
due to static electricity.
tin-plated cans, the containers should be made of rustproof material (such
as aluminum, glass, or plastic).
5.3 Variations in the amount of moisture present affect the
mass and hence the market value of a lot of material sold at a
7. Sampling and Test Specimens
definitepriceperunitmass.Knowledgeofthemoisturecontent
7.1 Primary Sampling Unit—Consider bales or other ship-
or regain can be accordingly an important financial consider-
ation. ping containers to be the primary sampling unit.
7.2 Laboratory Sample Unit—As a laboratory sample unit
5.4 Moisture content variation affects lap, sliver, and roving
for acceptance testing, take at random from the primary
linear density which in turn controls yarn number variation.
sampling units as directed in Practice D1441.
5.5 The mass of the oven-dry specimen used in this method
7.3 Since the purpose of this test method is to determine the
is the mass observed after the specimen has been dried in an
moisture content of the cotton in the shipping containers in the
oven supplied with ambient air. The observed mass is accord-
lot sample, the laboratory sampling units are taken directly
ingly subject to minor variations as discussed in 3.6.1. These
from the shipping container and placed directly into the sample
variations, however, are believed to be without significance in
container. Therefore, for this test method, laboratory sampling
commercial transactions.
units will be used as specimens and the terms “laboratory
sampling unit,” “sample,” and “specimen” can be used inter-
6. Apparatus
changeably.
6.1 Oven, thermostatically controlled at a temperature of
7.4 Sample Size:
105 6 2°C (220 6 4°F) with fan-forced ventilation and
7.4.1 The recommended minimum size for a specimen of
preferably equipped with a balance that permits weighing the
lint cotton or waste containing at least 50 % lint cotton is 5 g.
specimens without opening the oven.The air entering the oven
7.4.2 The recommended minimum size for a specimen of
must come from the standard atmosphere for testing textiles.
waste containing less than 50 % lint cotton is 10 g.
7.4.3 It is anticipated that only one specimen will be tested
6.2 Balance(s), of sufficient capacity to weigh the speci-
from each sample container. However, a 1-L (1-qt) container
mensinthecontainersthatwillbeusedandhavingasensitivity
will hold ample material for testing more than one specimen.
of 0.01 g.
The container should be well filled with the material being
NOTE 2—Although all the weighing can be done on the oven balance,
sampled to minimize changes in moisture content caused by
it is more convenient and the work can be completed more quickly if a
confined ambient air.
separate balance is available for weighing the specimens before drying.
7.4.4 In identifying containers or specimens, do not use any
Otherwise, the oven must be allowed to cool to room temperature before
material of variable moisture content. For example, do not
a new set of specimens can be weighed.
place identifying tags or slips of paper inside the sample
6.3 Weighing Containers, to be used when the specimens
containers and do not paste labels on the outside if the
are weighed in the oven (see 9.1.1 and 9.2).
specimens are to be weighed in the containers. Identify
6.3.1 The weighing containers may be perforated metal
containers by etching, stamping, or by scratching numbers on
baskets or shallow pans, of a size to fit the particular oven in
them, or by marking with crayon, ink, or paint.
which they are used. For specimens containing particles of
7.5 Sample Collection:
foreign matter that are easily shaken out, use baskets made of
7.5.1 When sampling lint cotton as it passes through (1) lint
or lined with wire screening fine enough to hold the trash, or
cleaners or condensers in the ginnery, (2) opening and cleaning
line the lower part of the basket with metal foil, but this
machinery in the mill, or (3) mechanical or pneumatic convey-
technique may prolong the drying period required.
ors between machines, take the specimen as the material flows
6.3.2 Weighing Bottles or Weighing Cans, with tight-fitting
past the sampling location. Place it in the sample container
covers, for use with the desiccator procedure (9.1.2 and 9.4).
without delay, and immediately close the container with a
To expedite drying, the diameter of each container should be
tightly fitting cover.
greater than its height.
7.5.2 Sliver and roving are usually in approximate moisture
6.4 Desiccator, large enough to hold as many weighing equilibrium with the air in the mill. Take short sections from a
containers as will be dried at one time. (For the desiccator number of strands as directed in 7.5.1 and place enough of
procedure only, see 9.1.2 and 9.4.) them in the container so that the total mass is as specified in
D2495 − 07 (2012)
2 2 2 2
7.4. Extreme haste is not necessary, but avoid handling the n 5 t 3s /E 5 15.4 3s (1)
~ !
material more than necessary to minimize adsorption of
where:
moisture from the hands. Immediately after the sample has
n = number of specimens (rounded upward to a whole
been placed in the container, close the latter with a tightly
number),
fitting cover.
s = reliable estimate of the standard deviation of indi-
7.5.3 To sample raw cotton in bales, cut out a section
vidual observations on similar materials in the user’s
approximately 0.15 m (6 in.) wide across the bale and at least
laboratory under conditions of single-operator
0.15mdeepfromthespacebetweentwobaleties.Immediately
precision,
take the specimen (1) by taking the surface cotton from the
t = 1.960, the value of Student’s t for infinite degrees of
bottom of the cavity, or (2) by pulling cotton from the face of
freedom, for two-sided limits, and a 95 % probabil-
the section that was nearest the inside of the bale.
ity level (t = 3.842),
7.5.4 When the material is far from moisture equilibrium
E = 0.50 percentage points, the value of the allowable
with the surrounding air, seal the containers as quickly as
variation of the test result, and
possibleanddonottaketimetoadjustthespecimentoanexact 2 2
15.4 =
a value calculated from t /E .
mass. If specimens are taken while the material is very dry
7.6.2 No Reliable Estimate of s—When there is no reliable
(less than 2 %), the containers must not be opened before the
estimate of s for the user’s laboratory, Eq 1 should not be used
first weighing.
directly. Instead, specify the fixed numbers of specimens
7.5.5 When sampling material over a period of time (for
shown in Table 1. These numbers of specimens are calculated
example, in ginning or other processing experiments that are
using values of s that are listed in Table 1 and which are
not conducted under controlled atmospheric conditions), take
somewhat larger values of s than are usually found in practice.
at least three specimens from each lot: one near the beginning
When a reliable estimate ofs for the user’s laboratory becomes
of the test, one at about the middle, and one at the end. If the
available, Eq 1 will usually require fewer specimens than are
experiment runs for more than 2 h, take additional specimens
listed in Table 1.
so that the time interval between specimens does not exceed 1
h. If atmospheric conditions are changing rapidly, it may be
8. Conditioning
necessary to sample as often as every 15 min.
8.1 Since the purpose of this method is to determine the
7.5.6 When the material to be tested comprises a number of
moisture content of the material at a specified time or under
bales of raw cotton, or a number of finished units of stock in
prevailing conditions, do not precondition or condition the
process,suchaspickerlaps,cansofsliver,orbobbinsofroving
specimens after they are taken.
all sampled at one time, take one or more specimens from each
such unit if the number of units is not greater than the number
9. Procedure
of specimens required (see Section 9). Otherwise, take one
9.1 Alternative Weighing Procedures:
specimen from each of the required number of units drawn at
9.1.1 Oven-Balance Procedure—An oven with a built-in
random from the entire quantity to be represented by the
balance is usually preferred for speed and convenience. The
specimens.
precisionofsuchequipmentisadequateformosttestpurposes,
7.5.7 When sampling stock in process from a group of
the error in weighing being less than the usual sampling error.
machines, take one or more specimens from each machine if
When the equipment is in good condition and the procedure is
the number of machines is not greater than the number of
carried out exactly as specified, moisture content or moisture
specimens required (see Section 9). Otherwise, take one
regain may be determined within 60.5 percentage points at the
specimen from each of the required number of machines
95 % probability level.
selected at random. If the machines, such as drawing frames,
9.1.2 Desiccator Procedure—When an oven with a built-in
combers, or roving frames, have two to six points at which
balance is not
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