ASTM C1134-23

Standard Test Method for Water Retention of Rigid Thermal Insulations Following Partial Immersion

SIGNIFICANCE AND USE
4.1 Materials less than or equal to 15 mm (0.59 in.) in thickness shall not be tested in accordance with this test method in order to avoid complete immersion of the specimens. This type of exposure is beyond the scope of this test method.  
4.2 This test method is used to assess both the short-term water retention and the long-term water retention. The short-term water retention is assessed as the average of the water retained following partial immersion intervals of 0.75-h and 3.00-h, in kilograms per square meter (percent by volume) (for materials tested at 25.4 mm (1.00 in.) thickness). The long-term water retention is assessed as the water retained following a 168-h partial immersion interval, in kilograms per square meter (percent by volume) (for materials tested at 25.4 mm (1.00 in.) thickness).  
4.3 Materials shall be tested at both actual product thickness and 25.4 mm (1.00 in.) thickness provided the materials can be cut to a thickness of 25.4 mm (1.00 in.) without changing the original character of the materials. If a product cannot be cut without changing the original character of the material, the corresponding information shall be provided in the test report. Results shall be reported on the basis of equal nominal wetted specimen surface area (in units of kilograms per square meter) for materials tested at actual product thickness and on the basis of equal specimen volume (in units of percent by volume) for materials tested at 25.4 mm (1.00 in.) thickness. If a product cannot be cut to a thickness of 25.4 mm (1.00 in.) or if the actual product thickness is less than 25.4 mm (1.00 in.) but greater than 15 mm (0.59 in.), the product shall only be tested at actual product thickness and results only reported on the basis of equal nominal wetted specimen surface area.  
4.3.1 By reporting results on the basis of equal nominal wetted specimen surface area, specimens of different thicknesses can be compared equitably. For some specimens, the water intake ...
SCOPE
1.1 This test method determines the amount of water retained (including surface water) by rigid block and board thermal insulations used in building construction applications after these materials have been partially immersed in liquid water for prescribed time intervals under isothermal conditions. This test method is intended to be used for the characterization of materials in the laboratory. It is not intended to simulate any particular environmental condition potentially encountered in building construction applications.  
1.2 This test method does not address all the possible mechanisms of water intake and retention and related phenomena for rigid thermal insulations. It relates only to those conditions outlined in 1.1. Determination of moisture accumulation in thermal insulations due to complete immersion, water vapor transmission, internal condensation, freeze-thaw cycling, or a combination of these effects requires different test procedures.  
1.3 Each partial immersion interval is followed by a brief free-drainage period. This test method does not address or attempt to quantify the drainage characteristics of materials. Therefore, results for materials with different internal structure and porosity, such as cellular materials and fibrous materials, are not necessarily directly comparable. Also, test results for specimens of different thickness are not necessarily directly comparable because of porosity effects. The surface characteristics of a material also affect drainage. It is possible that specimens with rough surfaces will retain more surface water than specimens with smooth surfaces, and that surface treatment during specimen preparation will affect water intake and retention. Therefore, it is not advisable to directly compare results for materials with different surface characteristics.  
1.4 For most materials the size of the test specimens is small compared with the size of the products actually inst...

General Information

• Status: Published
• Publication Date: 28-Feb-2023
• ICS: 27.220 - Heat recovery. Thermal insulation
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.33 - Insulation Finishes and Moisture

Relations

• Refers: ASTM C168-24 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 15-Apr-2024
• Refers: ASTM C168-18 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 15-Apr-2018
• Refers: ASTM C168-17 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 01-Jun-2017
• Refers: ASTM C168-15a - Standard Terminology Relating to Thermal Insulation
• Effective Date: 15-Oct-2015
• Refers: ASTM C168-15 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 01-Jun-2015
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM C168-13 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 01-Apr-2013
• Refers: ASTM E691-11 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2011
• Refers: ASTM C168-10 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 01-Jan-2010
• Refers: ASTM C168-08b - Standard Terminology Relating to Thermal Insulation
• Effective Date: 15-Dec-2008
• Refers: ASTM E691-08 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Oct-2008
• Refers: ASTM C168-08a - Standard Terminology Relating to Thermal Insulation
• Effective Date: 01-Sep-2008
• Refers: ASTM C168-08 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 01-Jun-2008
• Refers: ASTM E691-05 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2005
• Refers: ASTM C168-05a - Standard Terminology Relating to Thermal Insulation
• Effective Date: 01-Nov-2005

Overview

ASTM C1134-23 is the standardized test method for determining the water retention of rigid thermal insulation products following partial immersion. Developed by ASTM International, this standard provides an objective laboratory procedure for assessing how much water is absorbed and retained by rigid block and board insulation materials after they are partially submerged in liquid water for set time intervals. The results help characterize insulation materials used in building construction, ensuring product performance and facilitating informed selection and specification.

This method specifically applies to rigid thermal insulation products with thicknesses greater than 15 mm and is not intended to simulate real-world moisture exposure in field conditions.

Key Topics

• Scope Limitations

  • Only rigid insulation materials thicker than 15 mm are suitable for testing.
  • The test focuses on partial immersion under controlled, isothermal laboratory conditions.
  • Does not address all mechanisms of moisture absorption, such as water vapor transmission or complete immersion.

• Water Retention Assessment

  • Measures both short-term (after 0.75 and 3 hours) and long-term (after 168 hours) water retention.
  • Results can be reported as kilograms per square meter (by wetted surface area) or percent by volume (for 25.4 mm thick specimens).
  • Provides a method to compare specimens equitably by standardizing specimen dimensions and reporting metrics.

• Test Methodology

  • Specifies sample preparation, immersion procedures, and weighing protocols.
  • Testing includes conditioning specimens to constant mass, controlled temperature and humidity during testing, and draining post-immersion prior to final mass determination.
  • Determines density for reference and requires reporting of unusual test observations (e.g., warping or cracking).

• Reporting and Comparability

  • Test reports must include material identification, specimen description, test conditions, and both short and long-term retention results.
  • Due to differences in material structure and surface characteristics, direct comparison across different product types or thicknesses is discouraged unless reporting is standardized.

Applications

ASTM C1134-23 is an essential reference for:

• Building product manufacturers: Evaluating and qualifying rigid insulation materials for moisture resistance.
• Architects and engineers: Selecting appropriate insulation based on water retention performance.
• Specifiers and quality assurance personnel: Verifying compliance for construction documents, product submittals, and regulatory requirements.
• Laboratory technicians and product developers: Conducting product research, development, and comparative material analysis.

The standard’s protocols support quality assurance processes and ensure that insulation materials used in construction will maintain their thermal performance by minimizing unwanted water absorption. Although laboratory-based, the method provides baseline moisture absorption data relevant to long-term durability in building applications.

Related Standards

Several ASTM standards are referenced or related to ASTM C1134-23:

• ASTM C168 - Terminology Relating to Thermal Insulation: Provides definitions used throughout C1134.
• ASTM E691 - Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method: Basis for evaluating test precision and reproducibility.
• Other moisture and thermal insulation test methods: For comprehensive moisture performance assessment, consider standards addressing water vapor transmission, full immersion, freeze-thaw cycling, and internal condensation.

By following ASTM C1134-23, stakeholders can objectively assess and compare the water retention characteristics of rigid thermal insulation products, contributing to more durable, energy-efficient buildings and reliable material performance.

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: C1134 − 23
Standard Test Method for
Water Retention of Rigid Thermal Insulations Following
Partial Immersion
This standard is issued under the fixed designation C1134; 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 the corresponding products are different, it is possible that the
test results will be misleading.
1.1 This test method determines the amount of water re-
tained (including surface water) by rigid block and board 1.5 The values stated in SI units are to be regarded as
thermal insulations used in building construction applications standard. The values given in parentheses are mathematical
after these materials have been partially immersed in liquid conversions to inch-pound units that are provided for informa-
water for prescribed time intervals under isothermal condi- tion only and are not considered standard.
tions. This test method is intended to be used for the charac-
1.6 This standard does not purport to address all of the
terization of materials in the laboratory. It is not intended to
safety concerns, if any, associated with its use. It is the
simulate any particular environmental condition potentially
responsibility of the user of this standard to establish appro-
encountered in building construction applications.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.2 This test method does not address all the possible
1.7 This international standard was developed in accor-
mechanisms of water intake and retention and related phenom-
dance with internationally recognized principles on standard-
ena for rigid thermal insulations. It relates only to those
ization established in the Decision on Principles for the
conditions outlined in 1.1. Determination of moisture accumu-
Development of International Standards, Guides and Recom-
lation in thermal insulations due to complete immersion, water
mendations issued by the World Trade Organization Technical
vapor transmission, internal condensation, freeze-thaw cycling,
Barriers to Trade (TBT) Committee.
or a combination of these effects requires different test proce-
dures.
2. Referenced Documents
1.3 Each partial immersion interval is followed by a brief
2.1 ASTM Standards:
free-drainage period. This test method does not address or
C168 Terminology Relating to Thermal Insulation
attempt to quantify the drainage characteristics of materials.
E691 Practice for Conducting an Interlaboratory Study to
Therefore, results for materials with different internal structure
Determine the Precision of a Test Method
and porosity, such as cellular materials and fibrous materials,
are not necessarily directly comparable. Also, test results for
3. Terminology
specimens of different thickness are not necessarily directly
3.1 Definitions—Terminology C168 applies to terms used in
comparable because of porosity effects. The surface character-
this test method.
istics of a material also affect drainage. It is possible that
3.2 Descriptions of Terms Specific to This Standard:
specimens with rough surfaces will retain more surface water
3.2.1 WR —short-term water retention rating.
S
than specimens with smooth surfaces, and that surface treat-
ment during specimen preparation will affect water intake and 3.2.2 WR —long-term water retention rating.
L
retention. Therefore, it is not advisable to directly compare
4. Significance and Use
results for materials with different surface characteristics.
4.1 Materials less than or equal to 15 mm (0.59 in.) in
1.4 For most materials the size of the test specimens is small
thickness shall not be tested in accordance with this test
compared with the size of the products actually installed in the
method in order to avoid complete immersion of the speci-
field. If the surface-to-volume ratios for the test specimens and
mens. This type of exposure is beyond the scope of this test
method.
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. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 1, 2023. Published March 2023. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
ε1
approved in 1990. Last previous edition approved in 2017 as C1134 – 17 . DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C1134-23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1134 − 23
4.2 This test method is used to assess both the short-term 5.2 Immersion Tank—The immersion tank shall consist of
water retention and the long-term water retention. The short- an open tank of sufficient size to accommodate at least three
term water retention is assessed as the average of the water specimens. Included in the construction of the tank shall be a
retained following partial immersion intervals of 0.75-h and means for securing the specimens in a level position, that is, a
3.00-h, in kilograms per square meter (percent by volume) (for noncorrosive support for the bottom surface of the specimens
materials tested at 25.4 mm (1.00 in.) thickness). The long- and a similar constraining device for the top surface. The
term water retention is assessed as the water retained following support and constraining devices shall not contact more than
a 168-h partial immersion interval, in kilograms per square 15 % of the specimen surfaces. The pressure exerted on the
meter (percent by volume) (for materials tested at 25.4 mm specimens by the constraining device for the top surface shall
(1.00 in.) thickness). be limited to that required to counteract any buoyant force
exerted by the specimens at the beginning of the test. The
4.3 Materials shall be tested at both actual product thickness
immersion tank shall be provided with a water overflow level,
and 25.4 mm (1.00 in.) thickness provided the materials can be
as shown in Fig. 1.
cut to a thickness of 25.4 mm (1.00 in.) without changing the
original character of the materials. If a product cannot be cut 5.3 Balance—The balance shall have a sensitivity of at least
0.1 g. For some measurements, such a sensitivity will be more
without changing the original character of the material, the
corresponding information shall be provided in the test report. than is required, in which case a sensitivity of at least 0.1 % of
the total mass of the specimen after immersion and the
Results shall be reported on the basis of equal nominal wetted
specimen surface area (in units of kilograms per square meter) weighing container is acceptable. See 7.4.1. To achieve these
sensitivities, it is possible that two different balances will be
for materials tested at actual product thickness and on the basis
of equal specimen volume (in units of percent by volume) for required.
materials tested at 25.4 mm (1.00 in.) thickness. If a product
5.4 Weighing Container—The weighing container shall be
cannot be cut to a thickness of 25.4 mm (1.00 in.) or if the
made of a nonabsorbent, waterproof, lightweight material and
actual product thickness is less than 25.4 mm (1.00 in.) but
shall be large enough to allow a specimen to be laid flat in the
greater than 15 mm (0.59 in.), the product shall only be tested
container.
at actual product thickness and results only reported on the
5.5 Linear Measuring Instrument—The linear measuring
basis of equal nominal wetted specimen surface area.
instrument shall be capable of measuring specimen dimensions
4.3.1 By reporting results on the basis of equal nominal
to the nearest 0.25 mm (0.01 in.).
wetted specimen surface area, specimens of different thick-
5.6 Distilled or Deionized Water—Distilled or deionized
nesses can be compared equitably. For some specimens, the
water shall be used for testing.
water intake and retention primarily depends on the nominal
wetted surface area available for water intake.
5.7 Drainage Rack—The drainage rack shall be similar to
4.3.2 By reporting results on the basis of equal specimen
that shown in Figs. 2 and 3.
volume, specimens can be compared equitably using units that
6. Test Specimens
commonly are selected to represent results of water intake
testing (percent by volume). For some materials, water intake 6.1 Six test specimens shall be selected randomly from each
and retention primarily depends on the volume of the specimen sample. Only three specimens are required if the product is
available for water intake.
4.3.3 In most cases water retention is a secondary perfor-
mance characteristic that has an influence on a primary
performance characteristic, such as thermal performance, sur-
face accumulation of moisture (that will potentially contribute
to fungal growth), or localized collection of electrolytes (that
will potentially contribute to corrosion). Depending on the
primary performance characteristic that is of interest, the
preferred units for use in comparing the water retention of
different materials will be either kilograms per square meter or
percent by volume. (a) Typical dimensions for an immersion tank
4.4 Immersion times in addition to those required by this
test method shall be permitted to be selected provided that all
parties involved are in agreement.
4.5 The water retention characteristics of materials will
potentially be affected by conditions such as elevated tempera-
tures or chemical exposures.
5. Apparatus
5.1 Test Chamber—The test chamber or room where the test
(b) Typical dimensions for a noncorrosive support for the specimens
is to be run shall be maintained at a temperature of 23 6 2°C
(73 6 4°F) and a relative humidity of 50 6 5 %. FIG. 1 Immersion Tank
C1134 − 23
FIG. 2 Drainage Rack for Three Specimens
6.3.2 Composite materials normally produced with facings
or laminates shall be tested either with or without facings, as
required by the appropriate material specification. The corre-
sponding information shall be provided in the test report.
6.3.3 Ensure that no indentations are made when handling
specimens. Any specimens having surface indentations greater
than 5.0 mm (0.20 in.) in depth or any specimens damaged
during preparation shall be rejected and replaced by new
specimens prior to testing.
7. Procedure
7.1 Measure test specimen dimensions (length, l, width, w,
and thickness, t) to the nearest 0.2 mm (0.01 in.). Measure both
the length and width at three different locations and the
thickness at nine different locations, as shown in Fig. 4. The
average of each set of dimensions shall be used to calculate the
volume, V, of the specimen.
FIG. 3 Test Specimen in Drainage Rack
only to be tested at the actual product thickness or if the actual
product thickness is 5.4 mm (0.21 in.). See 4.3.
6.2 The test specimens shall be square with a length and
width of 300 6 10 mm (11.8 6 0.4 in.). The thickness of three
of the specimens shall be the same as that of the product or
sample from which the specimens are taken. The thickness of
the other three specimens shall be 25.4 6 1.6 mm (1.00 6 0.06
in.), provided the material is greater than 25.4 mm (1.00 in.) in
thickness. Specimens shall be cut to this size from thicker stock
if appropriate. See 4.3.
6.3 Specimen Preparation:
6.3.1 Materials normally produced with natural skins or
specially cut surfaces shall be tested with at least one skin or
surface intact, and that skin or surface shall be placed in
contact with the water when the test is conducted. The
FIG. 4 Measurement Locations for Determining Test Specimen
corresponding info
...

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: C1134 − 17 C1134 − 23
Standard Test Method for
Water Retention of Rigid Thermal Insulations Following
Partial Immersion
This standard is issued under the fixed designation C1134; 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—Editorially corrected 6.1 in January 2022.
1. Scope
1.1 This test method determines the amount of water retained (including surface water) by rigid block and board thermal
insulations used in building construction applications after these materials have been partially immersed in liquid water for
prescribed time intervals under isothermal conditions. This test method is intended to be used for the characterization of materials
in the laboratory. It is not intended to simulate any particular environmental condition potentially encountered in building
construction applications.
1.2 This test method does not address all the possible mechanisms of water intake and retention and related phenomena for rigid
thermal insulations. It relates only to those conditions outlined in 1.1. Determination of moisture accumulation in thermal
insulations due to complete immersion, water vapor transmission, internal condensation, freeze-thaw cycling, or a combination of
these effects requires different test procedures.
1.3 Each partial immersion interval is followed by a brief free-drainage period. This test method does not address or attempt to
quantify the drainage characteristics of materials. Therefore, results for materials with different internal structure and porosity, such
as cellular materials and fibrous materials, are not necessarily directly comparable. Also, test results for specimens of different
thickness are not necessarily directly comparable because of porosity effects. The surface characteristics of a material also affect
drainage. It is possible that specimens with rough surfaces will retain more surface water than specimens with smooth surfaces,
and that surface treatment during specimen preparation will affect water intake and retention. Therefore, it is not advisable to
directly compare results for materials with different surface characteristics.
1.4 For most materials the size of the test specimens is small compared with the size of the products actually installed in the field.
If the surface-to-volume ratios for the test specimens and the corresponding products are different, it is possible that the test results
will be misleading.
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to
inch-pound units that are provided for information only and are not considered standard.
1.6 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.
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 Oct. 1, 2017March 1, 2023. Published November 2017March 2023. Originally approved in 1990. Last previous edition approved in 20122017
ε1
as C1134 – 90 (2012)C1134 – 17 . DOI: 10.1520/C1134-17E01.10.1520/C1134-23.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1134 − 23
1.7 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.
2. Referenced Documents
2.1 ASTM Standards:
C168 Terminology Relating to Thermal Insulation
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions—Terminology C168 applies to terms used in this test method.
3.2 Descriptions of Terms Specific to This Standard:
3.2.1 WR —short-term water retention rating.
S
3.2.2 WR —long-term water retention rating.
L
4. Significance and Use
4.1 Materials less than or equal to 15 mm (0.59 in.) in thickness shall not be tested in accordance with this test method in order
to avoid complete immersion of the specimens. This type of exposure is beyond the scope of this test method.
4.2 This test method is used to assess both the short-term water retention and the long-term water retention. The short-term water
retention is assessed as the average of the water retained following partial immersion intervals of 0.75-h and 3.00-h, in kilograms
per square meter (percent by volume) (for materials tested at 25.4 mm (1.00 in.) thickness). The long-term water retention is
assessed as the water retained following a 168-h partial immersion interval, in kilograms per square meter (percent by volume)
(for materials tested at 25.4 mm (1.00 in.) thickness).
4.3 Materials shall be tested at both actual product thickness and 25.4 mm (1.00 in.) thickness provided the materials can be cut
to a thickness of 25.4 mm (1.00 in.) without changing the original character of the materials. If a product cannot be cut without
changing the original character of the material, the corresponding information shall be provided in the test report. Results shall be
reported on the basis of equal nominal wetted specimen surface area (in units of kilograms per square meter) for materials tested
at actual product thickness and on the basis of equal specimen volume (in units of percent by volume) for materials tested at 25.4
mm (1.00 in.) thickness. If a product cannot be cut to a thickness of 25.4 mm (1.00 in.) or if the actual product thickness is less
than 25.4 mm (1.00 in.) but greater than 15 mm (0.59 in.), the product shall only be tested at actual product thickness and results
only reported on the basis of equal nominal wetted specimen surface area.
4.3.1 By reporting results on the basis of equal nominal wetted specimen surface area, specimens of different thicknesses can be
compared equitably. For some specimens, the water intake and retention primarily depends on the nominal wetted surface area
available for water intake.
4.3.2 By reporting results on the basis of equal specimen volume, specimens can be compared equitably using units that commonly
are selected to represent results of water intake testing (percent by volume). For some materials, water intake and retention
primarily depends on the volume of the specimen available for water intake.
4.3.3 In most cases water retention is a secondary performance characteristic that has an influence on a primary performance
characteristic, such as thermal performance, surface accumulation of moisture (that will potentially contribute to fungal growth),
or localized collection of electrolytes (that will potentially contribute to corrosion). Depending on the primary performance
characteristic that is of interest, the preferred units for use in comparing the water retention of different materials will be either
kilograms per square meter or percent by volume.
4.4 Immersion times in addition to those required by this test method shall be permitted to be selected provided that all parties
involved are in agreement.
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.
C1134 − 23
4.5 The water retention characteristics of materials will potentially be affected by conditions such as elevated temperatures or
chemical exposures.
5. Apparatus
5.1 Test Chamber—The test chamber or room where the test is to be run shall be maintained at a temperature of 23 6 2°C (73
6 4°F) and a relative humidity of 50 6 5 %.
5.2 Immersion Tank—The immersion tank shall consist of an open tank of sufficient size to accommodate at least three specimens.
Included in the construction of the tank shall be a means for securing the specimens in a level position, that is, a noncorrosive
support for the bottom surface of the specimens and a similar constraining device for the top surface. The support and constraining
devices shall not contact more than 15 % of the specimen surfaces. The pressure exerted on the specimens by the constraining
device for the top surface shall be limited to that required to counteract any buoyant force exerted by the specimens at the
beginning of the test. The immersion tank shall be provided with a water overflow level, as shown in Fig. 1.
5.3 Balance—The balance shall have a sensitivity of at least 0.1 g. For some measurements, such a sensitivity will be more than
is required, in which case a sensitivity of at least 0.1 % of the total mass of the specimen after immersion and the weighing
container is acceptable. See 7.4.1. To achieve these sensitivities, it is possible that two different balances will be required.
5.4 Weighing Container—The weighing container shall be made of a nonabsorbent, waterproof, lightweight material and shall be
large enough to allow a specimen to be laid flat in the container.
5.5 Linear Measuring Instrument—The linear measuring instrument shall be capable of measuring specimen dimensions to the
nearest 0.25 mm (0.01 in.).
5.6 Distilled or Deionized Water—Distilled or deionized water shall be used for testing.
5.7 Drainage Rack—The drainage rack shall be similar to that shown in Figs. 2 and 3.
6. Test Specimens
6.1 Six test specimens shall be selected randomly from each sample. Only three specimens are required if the product is only to
be tested at the actual product thickness or if the actual product thickness is 5.4 mm (0.21 in.). See 4.3.
(a) Typical dimensions for an immersion tank
(b) Typical dimensions for a noncorrosive support for the specimens
FIG. 1 Immersion Tank
C1134 − 23
FIG. 2 Drainage Rack for Three Specimens
FIG. 3 Test Specimen in Drainage Rack
6.2 The test specimens shall be square with a length and width of 300 6 10 mm (11.8 6 0.4 in.). The thickness of three of the
specimens shall be the same as that of the product or sample from which the specimens are taken. The thickness of the other three
specimens shall be 25.4 6 1.6 mm (1.00 6 0.06 in.), provided the material is greater than 25.4 mm (1.00 in.) in thickness.
Specimens shall be cut to this size from thicker stock if appropriate. See 4.3.
6.3 Specimen Preparation:
6.3.1 Materials normally produced with natural skins or specially cut surfaces shall be tested with at least one skin or surface
intact, and that skin or surface shall be placed in contact with the water when the test is conducted. The corresponding information
shall be provided in the test report.
6.3.2 Composite materials normally produced with facings or laminates shall be tested either with or without facings, as required
by the appropriate material specification. The corresponding information shall be provided in the test report.
C1134 − 23
6.3.3 Ensure that no indentations are made when handling specimens. Any specimens having surface indentations greater than 5.0
mm (0.20 in.) in depth or any specimens damaged during preparation shall be rejected and replaced by new specimens prior to
testing.
7. Procedure
7.1 Measure test specimen dimensions (length, l, width, w, and thickness, t) to the nearest 0.2 mm (0.01 in.). Measure both the
length and width at three different locations and the thickness at nine different locations, as shown in Fig. 4. The average of each
set of dimensions shall be used to calculate the volume, V, of the spec
...