ASTM C1498-04a(2016)

Standard Test Method for Hygroscopic Sorption Isotherms of Building Materials

SIGNIFICANCE AND USE
4.1 The purpose of these tests is to obtain, for a specified temperature, by means of a specified laboratory procedure, the values of the equilibrium moisture content at various levels of RH. These values are used either as means to characterize the material or as material characteristics needed as input to appropriate computer models that can simulate wetting or drying potential of individual building materials or material assemblies under specified environmental conditions.  
4.2 A specified value of the equilibrium moisture content can also be used for material characterization. If this type of material characterization is called for in a material specification (for example, mineral or cellulose fiber insulation), the equilibrium at 95 ± 3 %RH shall be used.  
4.3 For ease and repeatability of measurements, the measurements for characterization are performed on adsorption isotherms. Though desorption is the reverse of adsorption, most porous materials reach different equilibrium levels during these two processes. Usually, the equilibrium moisture content on the desorption isotherm is higher than that on the adsorption isotherm for the same level of RH.
SCOPE
1.1 This test method specifies a laboratory procedure for the determination of hygroscopic sorption isotherms of any construction materials. The method was originally developed for the ASTM Thermal Insulation committee.  
1.2 For material characterization, the primary emphasis is on the adsorption isotherm (that is, sorption isotherm that describes the wetting process of the material from the oven-dry condition).  
1.3 Determination of desorption isotherm, (that is, sorption isotherm that describes the drying process of a material from the state of absolute saturation with water) is performed when information on drying characteristics of construction materials is required. Typically both adsorption and desorption isotherms are required for the purpose of hygrothermal models.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement 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.

General Information

• Status: Historical
• Publication Date: 14-Aug-2016
• ICS: 91.120.30 - Waterproofing
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.33 - Insulation Finishes and Moisture

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C1498 − 04a (Reapproved 2016)
Standard Test Method for
Hygroscopic Sorption Isotherms of Building Materials
This standard is issued under the fixed designation C1498; 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. Terminology
3.1 Definitions of Terms Specific to This Standard:
1.1 This test method specifies a laboratory procedure for the
determination of hygroscopic sorption isotherms of any con- 3.1.1 adsorption isotherm—the sorption isotherm measured
struction materials. The method was originally developed for exclusively during the hygroscopic adsorption process started
the ASTM Thermal Insulation committee. from the oven-dry condition.
3.1.2 desorption isotherm—the sorption isotherm measured
1.2 For material characterization, the primary emphasis is
exclusively during the hygroscopic desorption process started
on the adsorption isotherm (that is, sorption isotherm that
from the condition of full water saturation of the material.
describes the wetting process of the material from the oven-dry
condition).
3.1.3 hygroscopic adsorption—fixation of water molecules
from ambient air on surfaces of a material until equilibrium is
1.3 Determination of desorption isotherm, (that is, sorption
established.
isotherm that describes the drying process of a material from
the state of absolute saturation with water) is performed when
3.1.4 hygroscopic desorption—release of adsorbed water
information on drying characteristics of construction materials
molecules from surfaces of a material into the ambient air until
is required. Typically both adsorption and desorption isotherms
equilibrium is established.
are required for the purpose of hygrothermal models.
3.1.5 hysteresis—a physical phenomenon which makes the
1.4 The values stated in SI units are to be regarded as
desorption isotherm different from the adsorption isotherm due
standard. No other units of measurement are included in this
to the difference in the energy level of pore water.
standard.
3.1.6 moisture content, by mass—mass of water retained in
1.5 This standard does not purport to address all of the
the specimen divided by the dry mass of the specimen.
safety concerns, if any, associated with its use. It is the
3.1.7 moisture content, by volume—volume of water re-
responsibility of the user of this standard to establish appro-
tained in the specimen divided by the volume of the dry
priate safety and health practices and determine the applica-
specimen.
bility of regulatory limitations prior to use.
3.1.8 sorption isotherm—relationship between the relative
humidity (RH) (see Test Method E337) and the equilibrium
2. Referenced Documents
moisture content of the material, at a specified temperature.
2.1 ASTM Standards:
E104 Practice for Maintaining Constant Relative Humidity
4. Significance and Use
by Means of Aqueous Solutions
4.1 The purpose of these tests is to obtain, for a specified
E337 Test Method for Measuring Humidity with a Psy-
chrometer (the Measurement of Wet- and Dry-Bulb Tem- temperature, by means of a specified laboratory procedure, the
values of the equilibrium moisture content at various levels of
peratures)
RH. These values are used either as means to characterize the
material or as material characteristics needed as input to
appropriate computer models that can simulate wetting or
This test method is under the jurisdiction of ASTM Committee C16 on Thermal
drying potential of individual building materials or material
Insulation and is the direct responsibility of Subcommittee C16.33 on Insulation
Finishes and Moisture. assemblies under specified environmental conditions.
Current edition approved Aug. 15, 2016. Published August 2016. Originally
ɛ1
4.2 A specified value of the equilibrium moisture content
approved in 2001. Last previous edition approved in 2010 as C1498 – 04a (2010) .
DOI: 10.1520/C1498-04AR16.
can also be used for material characterization. If this type of
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
material characterization is called for in a material specification
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
(for example, mineral or cellulose fiber insulation), the equi-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. librium at 95 6 3 %RH shall be used.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1498 − 04a (2016)
4.3 For ease and repeatability of measurements, the mea- 6. Test Specimens
surements for characterization are performed on adsorption
6.1 A test specimen shall have a mass of at least 10 g. The
isotherms. Though desorption is the reverse of adsorption,
test specimen may be cut into several smaller pieces, but not
most porous materials reach different equilibrium levels during
powdered, to reduce the time to reach equilibrium with the
these two processes. Usually, the equilibrium moisture content
environment.
on the desorption isotherm is higher than that on the adsorption
6.2 A minimum of three specimens shall be tested in each
isotherm for the same level of RH.
environment. The test procedure as specified below, and the
5. Apparatus
precision of weighing in particular, shall be applied to each
specimen.
5.1 Weighing Cups—Weighing cups, made from non-
absorbing material , for example, glass, shall be provided with
7. Procedure
tight-fitting lids and the volume shall not be less than 15 cm .
5.2 Balance—An analytical balance capable of weighing the 7.1 Unless otherwise specified, the temperature of 23°C
cups within 1 mg shall be used. The accuracy of the balance shall be used for the test.
shall be at least 6 0.1 percent of the total specimen weight.
7.2 Determine the dry weight of each specimen by placing
5.3 Drying Oven—A ventilated drying oven, capable of
it in the drying oven (see 5.3) at the required temperature for a
maintaining the required drying temperature within 62K for
minimum of 24 h (see Note 1). Cool the specimen to room
temperatures less than 75°C and 64K for temperatures above
temperature (> 20–25°C) either in a desiccator with calcium
75°C, and a relative humidity of less than 10 %, shall be used.
chloride as desiccant or in a weighing cup with tight-fitting lids
In warm-humid laboratory environment or at low drying
and reweigh. Repeat the whole process, until three successive
temperatures, it will be necessary to provide a supply of dried
daily weighings agree to within 0.1 % of the specimen weight
air to achieve the less than 10 % relative humidity specification
obtained in the latest weighing. Record the average of these
in the drying oven.
three weights as the dry weight of the specimen.
5.4 Environment Chamber—The specimens shall be ex-
7.3 Determination of Adsorption Isotherms—Prior to testing
posed to controlled environmental conditions. The precise
water adsorption, each test specimen is to be dried to a constant
condition for the test environment shall be maintained in one of
mass. Note 1 provides recommendations on selection of the
the following two ways, (a) with desiccators placed in a room
appropriate temperature. Determination of adsorption iso-
with controlled temperature , or (b) with a climatic chamber.
therms can be performed with either the procedure described in
5.4.1 The test conditions can be generated within the
5.4.1 or with that described in 5.4.2 and the steps as described
desiccators that contain saturated salt solutions , (see also
below.
Practice E104). Since the partial pressure of the vapor above
7.3.1 Place the weighing cup with the dried specimen in the
the solution is strongly dependent on the temperature stability,
test environment having the lowest RH, typically about
temperature oscillation in the desiccator should be as small as
30 %RH. The test environment is achieved either in the
possible. The range 60.1K is recommended. The maximum
desiccator that contains a salt solution and placed in the
variation permitted by this standard shall not exceed 60.5K.
constant temperature room (5.4.1) or in the climatic chamber
Normally, the desiccators are placed inside a chamber or a
(5.4.2). Place the lid beside the weighing cup. Periodically
room with controlled temperature. In this case, it is recom-
weigh the weighing cup with the specimen until it is in
mended that the chamber or room is capable of maintaining the
equilibrium with the environment. At each weighing, before
test conditions within 61K.
the cup with the specimen is removed from the environment to
5.4.2 If the climatic chamber is used for the determination
the balance, put the lid on the cup. After weighing, return the
of the hygroscopic sorption isotherms, the chamber shall be
cup with the specimen to the test environment, with the lid
capable of maintaining the test conditions within 63 % for the
beside it. Constant mass is reached if in five successive
full range of RH. Temperature shall be maintained within
weighings, with 24 h intervals, the change of mass is less than
60.5K.
0.1 % of
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: C1498 − 04a (Reapproved 2010) C1498 − 04a (Reapproved 2016)
Standard Test Method for
Hygroscopic Sorption Isotherms of Building Materials
This standard is issued under the fixed designation C1498; 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.
ε NOTE—The units statement was editorially added and the units were editorially corrected in January 2011.
1. Scope
1.1 This test method specifies a laboratory procedure for the determination of hygroscopic sorption isotherms of any
construction materials. The method was originally developed for the ASTM Thermal Insulation committee.
1.2 For material characterization, the primary emphasis is on the adsorption isotherm (that is, sorption isotherm that describes
the wetting process of the material from the oven-dry condition).
1.3 Determination of desorption isotherm, (that is, sorption isotherm that describes the drying process of a material from the
state of absolute saturation with water) is performed when information on drying characteristics of construction materials is
required. Typically both adsorption and desorption isotherms are required for the purpose of hygrothermal models.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement 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.
2. Referenced Documents
2.1 ASTM Standards:
E104 Practice for Maintaining Constant Relative Humidity by Means of Aqueous Solutions
E337 Test Method for Measuring Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb Temperatures)
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 adsorption isotherm—the sorption isotherm measured exclusively during the hygroscopic adsorption process started from
the oven-dry condition.
3.1.2 desorption isotherm—the sorption isotherm measured exclusively during the hygroscopic desorption process started from
the condition of full water saturation of the material.
3.1.3 hygroscopic adsorption—fixation of water molecules from ambient air on surfaces of a material until equilibrium is
established.
3.1.4 hygroscopic desorption—release of adsorbed water molecules from surfaces of a material into the ambient air until
equilibrium is established.
3.1.5 hysteresis—a physical phenomenon which makes the desorption isotherm different from the adsorption isotherm due to
the difference in the energy level of pore water.
3.1.6 moisture content, by mass—mass of water retained in the specimen divided by the dry mass of the specimen.
3.1.7 moisture content, by volume—volume of water retained in the specimen divided by the volume of the dry specimen.
3.1.8 sorption isotherm—relationship between the relative humidity (RH) (see Test Method E337) and the equilibrium moisture
content of the material, at a specified temperature.
This test method is under the jurisdiction of ASTM Committee C16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.33 on Insulation Finishes
and Moisture.
Current edition approved Nov. 1, 2010Aug. 15, 2016. Published January 2011August 2016. Originally approved in 2001. Last previous edition approved in 20042010 as
ɛ1
C1498C1498 – 04a (2010) –04a. DOI: 10.1520/C1498-04AR10E01.10.1520/C1498-04AR16.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1498 − 04a (2016)
4. Significance and Use
4.1 The purpose of these tests is to obtain, for a specified temperature, by means of a specified laboratory procedure, the values
of the equilibrium moisture content at various levels of RH. These values are used either as means to characterize the material or
as material characteristics needed as input to appropriate computer models that can simulate wetting or drying potential of
individual building materials or material assemblies under specified environmental conditions.
4.2 A specified value of the equilibrium moisture content can also be used for material characterization. If this type of material
characterization is called for in a material specification (for example, mineral or cellulose fiber insulation), the equilibrium at 95
6 3 %RH shall be used.
4.3 For ease and repeatability of measurements, the measurements for characterization are performed on adsorption isotherms.
Though desorption is the reverse of adsorption, most porous materials reach different equilibrium levels during these two
processes. Usually, the equilibrium moisture content on the desorption isotherm is higher than that on the adsorption isotherm for
the same level of RH.
5. Apparatus
5.1 Weighing Cups—Weighing cups, made from non-absorbing material , for example, glass, shall be provided with tight-fitting
lids and the volume shall not be less than 15 cm .
5.2 Balance—An analytical balance capable of weighing the cups within 1 mg shall be used. The accuracy of the balance shall
be at least 6 0.1 percent of the total specimen weight.
5.3 Drying Oven—A ventilated drying oven, capable of maintaining the required drying temperature within 62K for
temperatures less than 75°C and 64K for temperatures above 75°C, and a relative humidity of less than 10 %, shall be used. In
warm-humid laboratory environment or at low drying temperatures, it will be necessary to provide a supply of dried air to achieve
the less than 10 % relative humidity specification in the drying oven.
5.4 Environment Chamber—The specimens shall be exposed to controlled environmental conditions. The precise condition for
the test environment shall be maintained in one of the following two ways, (a) with desiccators placed in a room with controlled
temperature , or (b) with a climatic chamber.
5.4.1 The test conditions can be generated within the desiccators that contain saturated salt solutions , (see also Practice E104).
Since the partial pressure of the vapor above the solution is strongly dependent on the temperature stability, temperature oscillation
in the desiccator should be as small as possible. The range 60.1K is recommended. The maximum variation permitted by this
standard shall not exceed 60.5K. Normally, the desiccators are placed inside a chamber or a room with controlled temperature.
In this case, it is recommended that the chamber or room is capable of maintaining the test conditions within 61K.
5.4.2 If the climatic chamber is used for the determination of the hygroscopic sorption isotherms, the chamber shall be capable
of maintaining the test conditions within 63 % for the full range of RH. Temperature shall be maintained within 60.5K.
5.5 Desiccator, with (a) calcium chloride as desiccant for drying, or (b) with saturated salt solution to generate specific relative
humidity level.
6. Test Specimens
6.1 A test specimen shall have a mass of at least 10 g. The test specimen may be cut into several smaller pieces, but not
powdered, to reduce the time to reach equilibrium with the environment.
6.2 A minimum of three specimens shall be tested in each environment. The test procedure as specified below, and the precision
of weighing in particular, shall be applied to each specimen.
7. Procedure
7.1 Unless otherwise specified, the temperature of 23°C shall be used for the test.
7.2 Determine the dry weight of each specimen by placing it in the drying oven (see 5.3) at the required temperature for a
minimum of 24 h (see Note 1). Cool the specimen to room temperature (> 20–25°C) either in a desiccator with calcium chloride
as desiccant or in a weighing cup with tight-fitting lids and reweigh. Repeat the whole process, until three successive daily
weighings agree to within 0.1 % of the specimen weight obtained in the latest weighing. Record the average of these three weights
as the dry weight of the specimen.
Normally, the specific area of a porous material is so large that adsorption on surfaces of the weighing cup may be omitted. Yet, when the amount of sorbed water is
low and requirements of high precision demand it, weighing of an empty container can be used as the way to improve the precision of sorption measurements.
Greenspan, L., “Humidity Fixed Points of Binary Saturated Aqueous Solutions,” Journal of Research of the National Bureau of Standards—A. Physics and Chemistry,
1977, Vol 81A, No 1.
This will increase the uncertainty of the test results in comparison with the procedure in 5.4.1. Therefore, when included in materials standards, due consideration shall
be given to the intended precision and either 5.4.1 or 5.4.2 shall be specified.
...