ASTM C870-96(2004)
(Practice)Standard Practice for Conditioning of Thermal Insulating Materials
Standard Practice for Conditioning of Thermal Insulating Materials
SIGNIFICANCE AND USE
The conditioning prescribed in this recommended practice is designed to obtain reproducible test results on thermal insulating materials. Results of tests obtained on these materials under uncontrolled atmospheric conditions may not be comparable with each other. Some of the physical properties of thermal insulating materials are influenced by relative humidity and temperature in a manner that affects the results of tests. In order that reliable comparisons may be made among different materials and products, and between different laboratories, it is necessary to standardize the humidity and temperature conditions to which insulating materials are subjected prior to and during testing.
Note 1—In some cases (for example, dimensionally unstable materials), the dry mass cannot easily be established and original mass has to be used.
It may be important to the user of thermal insulation to know physical properties (influenced by humidity) at the ambient conditions of use, as well as at standard conditions customarily specified for testing. In such instances, those special ambient conditions should be stated in the pertinent material specifications and test methods.
SCOPE
1.1 This practice covers the conditioning of thermal insulating materials for tests. Since prior exposure of insulating materials to high or low humidity may affect the equilibrium moisture content, a procedure is also given for preconditioning the materials.
1.2 This standard does not purport to address all of the safety problems, 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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Designation:C870–96(Reapproved 2004)
Standard Practice for
Conditioning of Thermal Insulating Materials
This standard is issued under the fixed designation C870; 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 percentage of the mass of the sample on either of the following
bases: (1) original mass (see 3.1.1); (2) moisture-free weight
1.1 This practice covers the conditioning of thermal insu-
(see 3.1.2).
lating materials for tests. Since prior exposure of insulating
3.1.1.1 Discussion—This is variously referred to as mois-
materials to high or low humidity may affect the equilibrium
ture content, or moisture “as is” or “as received.”
moisture content, a procedure is also given for preconditioning
3.1.1.2 Discussion—This is also referred to as moisture
the materials.
regain (frequently contracted to “regain”), or moisture content
1.2 This standard does not purport to address all of the
on the “oven-dry,” “moisture-free,” or “dry” basis.
safety concerns, if any, associated with its use. It is the
3.1.2 moisture equilibrium—the condition reached by a
responsibility of the user of this standard to establish appro-
sample when the net difference between the amount of mois-
priate safety and health practices and determine the applica-
ture sorbed and the amount desorbed, as shown by a change in
bility of regulatory limitations prior to use.
mass, shows no trend and becomes insignificant.
2. Referenced Documents
3.1.2.1 Discussion—Superficialequilibriumwiththefilmof
air in contact with the specimen is reached very rapidly. Stable
2.1 ASTM Standards:
equilibrium can be reached in a reasonable time only if the air
C168 Terminology Relating to Thermal Insulation
towhichthesampleisexposedisinmotion.Stableequilibrium
E41 Terminology Relating To Conditioning
with air in motion is considered to be realized when successive
E171 Specification for Atmospheres for Conditioning and
weighings do not show a progressive change in mass greater
Testing Flexible Barrier Materials
than the tolerances established for the various insulating
E337 Test Method for Measuring Humidity with a Psy-
materials.
chrometer (the Measurement of Wet- and Dry-Bulb Tem-
3.1.3 moisture regain—the moisture in a material deter-
peratures)
minedunderprescribedconditions,andexpressedasapercent-
2.2 ISO Standard:
age of the mass of the moisture-free specimen.
ISO 544 Standard Atmospheres for Conditioning and/or
3.1.3.1 Discussion—Moisture regain calculations are com-
Testing
monly based on the mass of a specimen that has been dried by
3. Terminology
heating in an oven. If the air in the oven contains moisture, the
oven-dried specimen will contain some moisture even when it
3.1 Definitions—Definitions of terms in the field of thermal
no longer shows a significant change in mass. In order to
insulating materials are given in Terminology C168. The
ensurethatthespecimenismoisture-free,itmustbeexposedto
following definitions are derived from Terminology E41:
desiccated air until it shows no further significant change in its
3.1.1 moisture content—the moisture present in a material,
mass. For drying temperatures above 100°C (212°F), the
as determined by definite prescribed methods, expressed as a
moisture content of the oven atmosphere is negligible.
3.1.3.2 Discussion—Moisture regain may be calculated
This practice is under the jurisdiction of ASTM Committee C16 on Thermal
frommoisturecontentusingEq1,andmoisturecontentmaybe
Insulation and is the direct responsibility of Subcommittee C16.31 on Chemical and
calculated from moisture regain using Eq 2 as follows:
Physical Properties.
Current edition approved Nov. 1, 2004. Published November 2004. Originally
C
R 5 3 100 (1)
approved in 1977. Last previous edition approved in 2000 as C870 – 77 (2000).
100 2 C
DOI: 10.1520/C0870-96R04.
R
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
C 5 3 100 (2)
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 100 1 R
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
where:
Available from American National Standards Institute, 11 West 42nd Street,
13th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C870–96 (2004)
and temperature in a manner that affects the results of tests. In
C = moisture content, % (see 3.1.1), and
order that reliable comparisons may be made among different
R = moisture regain, % (see 3.1.3).
materials and products, and between different laboratories, it is
3.2 Definitions of Terms Specific to This Standard—The
necessary to standardize the humidity and temperature condi-
following descriptions apply only to the usage of terms in this
tions to which insulating materials are subjected prior to and
practice:
during testing.
3.2.1 conditioned moisture equilibrium—The moisture con-
ditionreachedbyasampleorspecimenduringfreeexposureto
NOTE 1—In some cases (for example, dimensionally unstable materi-
movingaircontrolledatspecifiedconditions.Fortestpurposes,
als), the dry mass cannot easily be established and original mass has to be
moisture equilibrium must be reached by absorption, starting
used.
from a relatively low moisture content (see 3.2.4). Moisture
5.2 It may be important to the user of thermal insulation to
equilibrium for testing is considered to have been reached
know physical properties (influenced by humidity) at the
when the rate of increase in the mass of a sample or specimen
ambient conditions of use, as well as at standard conditions
does not exceed that specified for the material being tested. In
customarily specified for testing. In such instances, those
the absence of a specified rate, an increase of less than 0.1 %
special ambient conditions should be stated in the pertinent
of the sample mass after a 24-h exposure is considered
material specifications and test methods.
satisfactory.
3.2.2 preconditioned moisture equilibrium—The moisture
6. Apparatus
condition reached by a sample or specimen after exposure to
movingairatthestandardatmosphereforpreconditioning.The
6.1 Conditioning Room or Chamber:
final condition may be established after a specified period of
6.1.1 Equipment for maintaining the standard atmosphere
time, or at a moisture equilibrium that is considered to have
fortestinginsulatingmaterialsthroughouttheroomorchamber
been reached when the change in mass of a specimen in
within the tolerance given in 3.2.4, and including facilities for
successive weighings made at intervals of not less than 2 h
circulating the air over the exposed sample or specimen or,
does not exceed 0.2 % of the mass of the specimen.
alternatively, facilities such as a revolving rack for moving the
3.2.2.1 Discussion—Because the standard preconditioning
specimens in the prevailing atmosphere.
atmosphere covers a range of relative humidities, the close
6.1.2 Equipment for recording the temperature and relative
approachtoequilibriumis,ingeneral,warrantedonlyatthetop
humidity of the air in the conditioni
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