ASTM D7992/D7992M-23

Standard Practice for Elevated Temperature and Moisture Conditioning of Pultruded Fiber Reinforced Polymer (FRP) Composites Used in Structural Designs

SIGNIFICANCE AND USE
4.1 The elevated temperature and moisture conditioning procedures prescribed in this practice are designed to provide a standard procedure to be used to evaluate and compare the effect of elevated temperature and moisture conditioning under controlled laboratory conditions on pultruded FRP composites to be used in structural design applications. The conditioning procedures prescribed in this practice are designed to obtain reproducible results to compare and evaluate these materials but are not intended to produce equilibrium conditions or actual service conditions for these materials.
SCOPE
1.1 In general, it is feasible that the mechanical properties of FRP composites will be affected by environmental conditions such as exposure to moisture at elevated temperatures. In order to make reliable comparisons between different materials under elevated temperature and moisture environmental conditions, it is necessary to standardize the elevated temperature and moisture conditions to which specimens of these materials are subjected prior to and during testing. This practice defines procedures for elevated temperature and moisture conditioning of pultruded FRP composites intended for use in structural design applications. The conditioning medium representing elevated temperature and moisture exposure described in this standard practice is distilled water maintained at 37.8 ± 1.5°C [100 ± 3°F] for 1000 hours.  
1.2 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems has the potential to result in nonconformance with the standard.  
1.3 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.  
1.4 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.

General Information

• Status: Published
• Publication Date: 14-Dec-2023
• ICS: 83.120 - Reinforced plastics
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.18 - Reinforced Thermosetting Plastics

Relations

• Replaces: ASTM D7992/D7992M-15 - Standard Practice for Elevated Temperature and Moisture Conditioning of Pultruded Fiber Reinforced Polymer (FRP) Composites Used in Structural Designs
• Effective Date: 15-Dec-2023
• Refers: ASTM D883-24 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2024
• Refers: ASTM D883-23 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2023

Overview

ASTM D7992/D7992M-23 establishes a standardized practice for evaluating the effects of elevated temperature and moisture on pultruded fiber reinforced polymer (FRP) composites used in structural design applications. Developed by ASTM International, this standard addresses the importance of reproducible laboratory procedures for conditioning FRP composites, ensuring consistent results for comparison and evaluation of mechanical properties after exposure to environmental stresses.

By specifying detailed procedures for elevated temperature and moisture conditioning, ASTM D7992/D7992M-23 enhances the reliability of mechanical property testing for structural FRP composites. The practice is especially crucial for comparing various materials prior to their use in building and infrastructure projects, as environmental conditions such as heat and humidity can significantly impact composite performance.

Key Topics

• Significance of Environmental Conditioning
  The mechanical properties of pultruded FRP composites can degrade when exposed to moisture at elevated temperatures. Standardizing conditioning protocols allows for fair, accurate comparisons between different materials and manufacturing processes.

• Conditioning Procedure

  • Specimens are immersed in distilled water at 37.8 ± 1.5°C (100 ± 3°F) for 1000 hours.
  • The practice describes apparatus requirements for uniform exposure and residual monitoring.
  • The conditioning process is not intended to emulate real-world service or equilibrium conditions but rather to provide a controlled basis for comparative testing.

• Test Specimens and Sampling

  • Test specimens must be prepared and their origin documented according to relevant ASTM methods.
  • At least 10 samples are recommended for control conditions and another 10 for conditioned testing when determining characteristic values.
  • Initial baseline measurements are compared to post-conditioning mechanical property results.

• Reporting Requirements
  Reports referencing this standard must include:

  • Identification of the composite material
  • Specimen geometry and location
  • Any deviations from standard procedures
  • Testing timeframes and observable changes

Applications

ASTM D7992/D7992M-23 serves professionals in structural engineering, construction, and civil infrastructure who need to assess the durability and performance of pultruded FRP composites exposed to humid, high-temperature environments. Key applications include:

• Material Qualification and Comparison:
  Enables effective selection of FRP products by assessing their mechanical property retention after environmental conditioning.

• Design Validation:
  Supports engineers in confirming that chosen FRP composites are suitable for use in structures where exposure to moisture and heat is expected, such as bridges, buildings, or marine applications.

• Quality Control and Research:
  Provides a repeatable process for manufacturers or researchers developing new pultruded FRP formulations or evaluating batch consistency.

Related Standards

• ASTM D618 – Practice for Conditioning Plastics for Testing:
  Procedures for standard laboratory conditioning prior to testing.

• ASTM D883 – Terminology Relating to Plastics:
  Reference for terms and definitions relevant to plastic materials and composites.

• ASTM D6641/D6641M – Test Method for Compressive Properties of Polymer Matrix Composite Materials:
  Mechanical property testing for composites under compressive loading.

• ASTM D7290 – Practice for Evaluating Material Property Characteristic Values for Polymeric Composites in Civil Engineering:
  Statistical evaluation of material properties for design codes.

• ASTM D7745 – Practice for Testing Pultruded Composites:
  Guidance on sampling and test procedures specific to pultruded composite products.

By adhering to ASTM D7992/D7992M-23, stakeholders in the construction and composites industries can ensure consistency, safety, and durability in the specification and use of pultruded FRP structural components, particularly where exposure to challenging environmental conditions is expected.

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: D7992/D7992M − 23
Standard Practice for
Elevated Temperature and Moisture Conditioning of
Pultruded Fiber Reinforced Polymer (FRP) Composites Used
in Structural Designs
This standard is issued under the fixed designation D7992/D7992M; 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* 2. Referenced Documents
2.1 ASTM Standards:
1.1 In general, it is feasible that the mechanical properties of
D618 Practice for Conditioning Plastics for Testing
FRP composites will be affected by environmental conditions
D883 Terminology Relating to Plastics
such as exposure to moisture at elevated temperatures. In order
D3918 Terminology Relating to Reinforced Plastic Pul-
to make reliable comparisons between different materials under
truded Products (Withdrawn 2020)
elevated temperature and moisture environmental conditions, it
D6641/D6641M Test Method for Compressive Properties of
is necessary to standardize the elevated temperature and
Polymer Matrix Composite Materials Using a Combined
moisture conditions to which specimens of these materials are
Loading Compression (CLC) Test Fixture
subjected prior to and during testing. This practice defines
D7290 Practice for Evaluating Material Property Character-
procedures for elevated temperature and moisture conditioning
istic Values for Polymeric Composites for Civil Engineer-
of pultruded FRP composites intended for use in structural
ing Structural Applications
design applications. The conditioning medium representing
D7745 Practice for Testing Pultruded Composites
elevated temperature and moisture exposure described in this
standard practice is distilled water maintained at 37.8 6 1.5°C
3. Terminology
[100 6 3°F] for 1000 hours.
3.1 Definitions:
1.2 Units—The values stated in either SI units or inch- 3.1.1 standard laboratory temperature, n—a temperature of
pound units are to be regarded separately as standard. The
23 6 2°C [73.4 6 3.6°F]
values stated in each system are not necessarily exact equiva-
3.1.2 standard laboratory atmosphere, n—an atmosphere
lents; therefore, each system shall be used independently of the
having a temperature of 23 6 2°C [73.4 6 3.6°F] and a rela-
other. Combining values from the two systems has the potential
tive humidity of 50 6 10 %.
to result in nonconformance with the standard.
3.1.3 elevated temperature and moisture resistance, n—the
1.3 This standard does not purport to address all of the ability of a thermoset pultruded composite to withstand el-
safety concerns, if any, associated with its use. It is the evated temperature and moisture exposure at 37.8 6 1.5°C
responsibility of the user of this standard to establish appro- [100 6 3°F] for 1000 hours. This ability will be quantified in
terms of the % retention of the mechanical property of interest
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. as compared to samples held at standard laboratory atmo-
sphere.
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3.2 Terminology relating to pultruded composites is found
ization established in the Decision on Principles for the
in Terminology D3918.
Development of International Standards, Guides and Recom-
4. Significance and Use
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4.1 The elevated temperature and moisture conditioning
procedures prescribed in this practice are designed to provide
1 2
This test method is under the jurisdiction of ASTM Committee D20 on Plastics For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and is the direct responsibility of Subcommittee D20.18 on Reinforced Thermoset- contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
ting Plastics. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Dec. 15, 2023. Published January 2024. Originally the ASTM website.
approved in 2015. Last previous edition approved in 2015 as D7992/ The last approved version of this historical standard is referenced on
D7992M – 15.DOI: 10.1520/D7992_D7992M-23. www.astm.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7992/D7992M − 23
a standard procedure to be used to evaluate and compare the other at the grip area. The chamber dimensions need to be such
effect of elevated temperature and moisture conditioning under that the depth of the water necessary to immerse the samples is
controlled laboratory conditions on pultruded FRP composites no more than 0.5 m [19.7 in.]. The temperature of the water
to be used in structural design applications. The conditioning bath is to be monitored at least daily, and the water bath must
procedures prescribed in this practice are designed to obtain possess a cover in order to minimize loss of water to the air
reproducible results to compare and evaluate these materials through evaporation.
but are not intended to produce equilibrium conditions or
7.2 Water Pump—In order to reduce or minimize ‘dead
actual service conditions for these materials.
zones’ in the water bath of the conditioning chamber, a small
water pump (or similar device) shall be placed in the water
5. Sampling
bath. It is acceptable to utilize and air pump for this purpose;
5.1 Sampling shall be in accordance with the locations from
if such an air pump is used, the information shall be reported.
which test specimens shall be taken from the reinforced
pultruded composites as defined in Practice D7745. 8. Procedure
5.2 Sampling shall be in accordance with the ASTM test 8.1 Distilled water shall be used for all conditioning. Dis-
methods for the specific mechanical properties to be deter- tilled water is to be used to serve as a standard medium for the
mined. conditioning procedure; however, distilled water is not in-
tended to mimic field conditions.
6. Test Specimens
8.2 The presence of any residue in the water bath during the
6.1 The numbers and types of test specimens shall be in
exposure time shall be noted in the report as the presence of
accordance with the AST
...

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.
Designation: D7992/D7992M − 15 D7992/D7992M − 23
Standard Practice for
Elevated Temperature and Moisture Conditioning of
Pultruded Fiber Reinforced Polymer (FRP) Composites Used
in Structural Designs
This standard is issued under the fixed designation D7992/D7992M; 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 Scope*
1.1 In general, it is feasible that the mechanical properties of FRP composites will be affected by environmental conditions such
as exposure to moisture at elevated temperatures. In order to make reliable comparisons between different materials under elevated
temperature and moisture environmental conditions, it is necessary to standardize the elevated temperature and moisture conditions
to which specimens of these materials are subjected prior to and during testing. This practice defines procedures for elevated
temperature and moisture conditioning of pultruded FRP composites intended for use in structural design applications. The
conditioning medium representing elevated temperature and moisture exposure described in this standard practice is distilled water
maintained at 37.8 6 1.5°C (100 6 3°F)[100 6 3°F] for 1000 hours.
1.2 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in
each system may not beare not necessarily exact equivalents; therefore, each system shall be used independently of the other.
Combining values from the two systems may has the potential to result in nonconformance with the standard.
1.3 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 healthsafety, health, and environmental practices and determine
the applicability of regulatory limitations prior to use.
1.4 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:
D618 Practice for Conditioning Plastics for Testing
D883 Terminology Relating to Plastics
D3918 Terminology Relating to Reinforced Plastic Pultruded Products (Withdrawn 2020)
D6641/D6641M Test Method for Compressive Properties of Polymer Matrix Composite Materials Using a Combined Loading
Compression (CLC) Test Fixture
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.18 on Reinforced Thermosetting
Plastics.
Current edition approved Sept. 1, 2015Dec. 15, 2023. Published October 2015January 2024. Originally approved in 2015. Last previous edition approved in 2015 as
D7992/D7992M – 15.DOI: 10.1520/D7992_D7992M-15.10.1520/D7992_D7992M-23.
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.
The last approved version of this historical standard is referenced on www.astm.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7992/D7992M − 23
D7290 Practice for Evaluating Material Property Characteristic Values for Polymeric Composites for Civil Engineering
Structural Applications
D7745 Practice for Testing Pultruded Composites
3. Terminology
3.1 Definitions:
3.1.1 standard laboratory temperature, n—a temperature of 23 6 2°C (73.4 6 3.6°F)[73.4 6 3.6°F]
3.1.2 standard laboratory atmosphere, n—an atmosphere having a temperature of 23 6 2°C (73.4 6 3.6°F)[73.4 6 3.6°F] and a
relative humidity of 50 6 10 %.
3.1.3 elevated temperature and moisture resistance, n—the ability of a thermoset pultruded composite to withstand elevated
temperature and moisture exposure at 37.8 6 1.5°C (100 6 3°F)[100 6 3°F] for 1000 hours. This ability will be quantified in
terms of the % retention of the mechanical property of interest as compared to samples held at standard laboratory atmosphere.
3.2 Terminology relating to pultruded composites is found in Terminology D3918.
4. Significance and Use
4.1 The elevated temperature and moisture conditioning procedures prescribed in this practice are designed to provide a standard
procedure to be used to evaluate and compare the effect of elevated temperature and moisture conditioning under controlled
laboratory conditions on pultruded FRP composites to be used in structural design applications. The conditioning procedures
prescribed in this practice are designed to obtain reproducible results to compare and evaluate these materials but are not intended
to produce equilibrium conditions or actual service conditions for these materials.
5. Sampling
5.1 Sampling shall be in accordance with the locations from which test specimens shall be taken from the reinforced pultruded
composites as defined in Practice D7745.
5.2 Sampling shall be in accordance with the ASTM test methods for the specific mechanical properties to be determined.
6. Test Specimens
6.1 The numbers and types of test specimens shall be in accordance with the ASTM test methods for the specific mechanical
properties to be determined. If Practice D7290 is to be used to determine characteristic values for a particular mechanical property,
at least ten samples are needed for the control and ten samples are needed for the elevated temperature and moisture conditioning
for a total of at least 20 samples.
6.2 Test specimens shall be machined or otherwise fabricated to the test coupon geometry specified by the ASTM test method for
the property to be determined prior to their exposure to the environmental conditioning.
6.3 The thickness of the test specimens shall be the original product thickness without any machining of the surface. The specimen
thickness needs to be compatible with the thickness requirements of the mechanical property test method that will be used to
evaluate the samples.
6.4 All test specimens shall be conditioned in the standard laboratory at
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