ASTM D4920-98
(Terminology)Standard Terminology Relating to Moisture in Textiles
Standard Terminology Relating to Moisture in Textiles
SCOPE
1.1 This standard is a compilation of definitions of technical terms related to moisture in textiles. Terms that are generally understood or adequately defined in other readily available sources are not included.
1.2 For other ASTM defined conditioning terms, refer to Terminology E 41. For other terms associated with textiles, refer to Terminology D 123, Relating to Textiles.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 4920 – 98
Standard Terminology Relating to
Moisture in Textiles
This standard is issued under the fixed designation D 4920; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope ments are conducted. (See also standard atmosphere for
testing.)
1.1 This terminology is a compilation of definitions of
technical terms related to moisture in textiles. Terms that are
DISCUSSION—In the hierarchy of terms, atmosphere is the generic
generally understood or adequately defined in other readily term where the air is ambient with conditions “controlled” by local
weather and therefore variable. Atmosphere for testing is a delimited
available sources are not included.
term in which the use of the atmosphere is restricted for a certain
1.2 For other ASTM defined conditioning terms, refer to
purpose. In a standard atmosphere for testing, the conditions are
Terminology E 41. For other terms associated with textiles,
specified (standardized) and controlled for routine testing and for
refer to Terminology D 123, Relating to Textiles.
testing reproducibility. On this basis, there is no real reason for not
referring to the specified atmospheres that have been traditionally used
2. Referenced Documents
for testing glass textiles or tire cords, etc., as standard atmospheres
2.1 ASTM Standards:
for testing those materials.
D 123 Terminology Relating to Textiles
commercial allowance (CA), n—an arbitrary value, equal to
E 41 Terminology Relating to Conditioning
the commercial moisture regain, plus a specified allowance
for finish, used with the mass of scoured, oven-dried yarn, to
3. Terminology
compute (1) yarn linear density, (2) the commercial or legal
3.1 Definitions:
mass of a shipment or delivery of any specific textile
absolute humidity, n—the mass of water vapor present in a material (see also commercial moisture regain), or (3) the
unit volume of air.
mass of a specific component in the analysis of fiber blends.
D 1907, D 2494, D 3887
DISCUSSION—Common units of measure for absolute humidity are
commercial mass, n—billed mass as determined by a gener-
grams per cubic metre or grains per cubic foot. The amount of water
ally accepted method or as agreed upon between the pur-
vapor is also reported in terms of mass per unit mass of dry air, for
example, grams per kilogram, or grains per pound, of dry air. This value chaser and seller. D 2494
differs from values calculated on a volume basis and should not be
commercial moisture content, n—in wool, the moisture
referred to as absolute humidity. It is designated as humidity ratio,
calculated as a percentage of the mass of the wool, top, noils,
specific humidity, or moisture pick-up.
yarn, fabric, etc., in the “as-is” condition; that is, containing
whatever moisture, oil, grease, or other extraneous matter
absorption, n—a process in which one material (the absor-
that may be present. D2118
bent) takes in or absorbs another (the absorbate); as the
commercial moisture regain (CMR), n—a formally adopted,
absorption of moisture by fibers. (See also adsorption, and
arbitrary value, to be used with the oven-dried mass of
moisture equilibrium for testing. Compare desorption and
textile fibers, when calculating the commercial mass of a
resorption.) D 4772
shipment or delivery.
adsorption, n—a process in which the surface of a solid takes
on or adsorbs in an extremely thin layer molecules of gases,
DISCUSSION—The assigned commercial moisture regain value is
of dissolved substances, or of liquids with which it is in
usually higher than the experimental moisture regain value for the same
contact. (See also absorption and moisture equilibrium for
material.
testing. Compare desorption and resorption.)
condition, v—to bring a material to moisture equilibrium with
atmosphere for testing, n—air at ambient conditions of
a specified atmosphere.
relative humidity and temperature in which tests or experi-
desorption, n—a process in which a sorbed material is
released from another material, as the desorption of moisture
from fibers; the reverse of absorption, adsorption, or both.
This terminology is under the jurisdiction of ASTM Committee D-13 on
Textiles and is the direct responsibility of Subcommittee D13.51 on Chemical
dew point, n—the temperature below which condensation of
Conditioning and Performance.
water vapor begins to take place when the atmosphere is
Current edition approved Oct. 10, 1996. Published February 1997. Originally
cooled.
published as D 4920 – 89. Last previous edition D 4920 – 96b.
Annual Book of ASTM Standards, Vol 07.01.
DISCUSSION—As air is cooled, the amount of water vapor which it can
Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 4920
hold decreases. If air is cooled sufficiently, the saturation water-vapor which equilibrium is approached. Because of this difference, equilib-
pressure becomes equal to the actual water-vapor pressure and any rium for textiles should be approached from the dry (but not moisture-
further cooling beyond this point will normally result in the conden- free) side which is faster. Equilibrium with air in motion is considered
sation of moisture. to be achieved when successive weighings at specified time intervals do
not show a change in mass greater than the tolerance established for the
humidity, n—the condition of the atmosphere in respect to
material. If there is no established tolerance, consider 0.1 % of the mass
water vapor. (Compare absolute humidity and relative
after a 2-h exposure as satisfactory.
humidity.)
moisture equilibrium, n—for preconditioning, the moisture
hygrometer, n—any instrument for measuring the humidity of
condition reached by a material during free exposure to
the atmosphere.
moving air in the standard atmosphere for preconditioning.
moisture, n—as used with textiles, water absorbed, adsorbed,
D 1776
or resorbed by a material. (See also water.)
moisture equilibrium, n—for testing, the condition reached
moisture as-is, n—deprecated term. See moisture content.
by a material during free exposure to moving air in a
moisture as-received, n—deprecated term. See moisture
specified atmosphere for testing. D 885, D 885M, D 1776
content.
moisture-free, adj—in textiles, a descriptive term for a mate-
moisture content, n—that part of the total mass of a material
rial that (1) has been exposed to a flow of desiccated air at
that is absorbed or adsorbed water, compared to the total
a specified temperature until there is no further significant
mass. (Compare moisture pick-up and moisture regain.)
change in mass, or (2) has been treated by a distillation
DISCUSSION—Moisture is usually expressed as a percentage and is
process using a suitable solvent. (Syn. zero-moisture.)
calculated using the equation:
(Compare moisture equilibrium.)
C 5 100 ~A 2 D!/A
DISCUSSION—Moisture determinations frequently involve the change
in mass of an oven-dried specimen. If the air in the oven contains
where:
moisture, the oven-dried specimen will also contain some moisture
C 5 moisture content, %,
even though it no longer shows a significant change in mass. This is due
A 5 mass of material before drying, and
to the establishment of moisture equilibrium under the existing condi-
D 5 mass of the dried material.
tions. To ensure that the specimen is actually moisture-free, it must be
There is a relationship between moisture content and mois-
exposed to desiccated air until it shows no further significant change in
ture pick-up since both may be calculated from the same data.
mass. Although heating textiles in dessicated air to temperatures as high
as 110°C increases the rate of moisture loss without changing the final
The difference is in the bases used for calculating the percent-
equilibrium mass of the moisture-free textile, heating also increases the
ages, original versus dried material mass. The relationship
possibility of removing other matter. The distillation process may be
between moisture content and moisture pick-up is shown by
substituted provided the textile does not contain any distillable,
the equations:
water-soluble matter.
C 5 100 P/~100 1 P!
moisture pick-up, n—the mass of absorbed and adsorbed
P 5 100 C/~100 2 C!
water that is held by a material, compared to the mass of the
dried material. (Compare moisture content and moisture
where:
regain.)
C 5 moistu
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.