ASTM C793-23

Standard Test Method for Effects of Laboratory Accelerated Weathering on Elastomeric Joint Sealants

SIGNIFICANCE AND USE
5.1 It is known that solar radiation contributes to the degradation of sealants in exterior building joints. The use of a laboratory accelerated weathering machine with actinic radiation, moisture and heat appears to be a feasible means to give indications of early degradation by the appearance of sealant cracking. However, simulated weather factors in combination with extension may produce more severe degradation than weather factors only. Therefore, the effect of the weathering test is made more sensitive by the addition of the bending of the specimen at cold temperature.
SCOPE
1.1 This test method covers a laboratory procedure for determining the effects of accelerated weathering on cured-in-place elastomeric joint sealants (single- and multicomponent) for use in building construction.  
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.  
1.3 The committee with jurisdiction over this standard is not aware of any comparable standards published by other ASTM committees or other organizations.  
1.4 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.  
1.5 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: 30-Apr-2023
• ICS: 83.060 - Rubber
• ICS: 91.100.50 - Binders. Sealing materials
• Technical Committee: C24 - Building Seals and Sealants
• Drafting Committee: C24.40 - Weathering

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: C793 − 23
Standard Test Method for
Effects of Laboratory Accelerated Weathering on
1
Elastomeric Joint Sealants
This standard is issued under the fixed designation C793; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 3. Terminology
3.1 Definitions—See Terminology C717 for applicable defi-
1.1 This test method covers a laboratory procedure for
nitions of the following terms: cure, elastomeric, joint, sealant,
determining the effects of accelerated weathering on cured-in-
and substrate.
place elastomeric joint sealants (single- and multicomponent)
for use in building construction.
4. Summary of Test Method
1.2 The values stated in SI units are to be regarded as the
4.1 Three sealant specimens are spread on aluminum plates
standard. The values in parentheses are for information only.
and exposed in one of the laboratory accelerated weathering
1.3 The committee with jurisdiction over this standard is not
chambers specified in Section 6 and operated in accordance
aware of any comparable standards published by other ASTM
with specifications in Section 8 and Practice C1442.
committees or other organizations.
4.2 Following this treatment the specimens are exposed for
1.4 This standard does not purport to address all of the
24 h in a freezer maintained at −26 °C 6 2 °C (−15 °F 6 4 °F).
safety concerns, if any, associated with its use. It is the
4.3 At the end of the cold exposure, the specimens are bent
responsibility of the user of this standard to establish appro-
over a mandrel within 1 s at the specified temperature.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
5. Significance and Use
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
5.1 It is known that solar radiation contributes to the
ization established in the Decision on Principles for the
degradation of sealants in exterior building joints. The use of a
Development of International Standards, Guides and Recom-
laboratory accelerated weathering machine with actinic
mendations issued by the World Trade Organization Technical
radiation, moisture and heat appears to be a feasible means to
Barriers to Trade (TBT) Committee.
give indications of early degradation by the appearance of
sealant cracking. However, simulated weather factors in com-
2. Referenced Documents
bination with extension may produce more severe degradation
2 than weather factors only. Therefore, the effect of the weath-
2.1 ASTM Standards:
ering test is made more sensitive by the addition of the bending
C717 Terminology of Building Seals and Sealants
of the specimen at cold temperature.
C1442 Practice for Conducting Tests on Sealants Using
Artificial Weathering Apparatus
6. Apparatus
G151 Practice for Exposing Nonmetallic Materials in Accel-
erated Test Devices that Use Laboratory Light Sources
6.1 Exposure Apparatus—The exposure apparatus shall be
one of the three types of laboratory accelerated weathering
devices described in Practice C1442 that use either xenon arc,
fluorescent UV, or open flame carbon arc radiation. Consult
1
This test method is under the jurisdiction of ASTM Committee C24 on Building
Practice C1442, Section 7 for the differences in test parameters
Seals and Sealants and is the direct responsibility of Subcommittee C24.40 on
Weathering.
among the devices. Because of differences in test conditions,
Current edition approved May 1, 2023. Published May 2023. Originally
test results may differ with the type of device used. The choice
approved in 1975. Last previous edition approved in 2017 as C793 – 05 (2017).
of device shall be by mutual agreement among the interested
DOI: 10.1520/C0793-23.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or parties.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
6.2 Freezer or Cold Box, having a temperature controlled
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. at −26 °C 6 2 °C (−15 °C 6 4 °F).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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C793 − 23
6.3 Rectangular Brass Frame, with inside dimensions tests
...

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: C793 − 05 (Reapproved 2017) C793 − 23
Standard Test Method for
Effects of Laboratory Accelerated Weathering on
1
Elastomeric Joint Sealants
This standard is issued under the fixed designation C793; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This test method covers a laboratory procedure for determining the effects of accelerated weathering on cured-in-place
elastomeric joint sealants (single- and multicomponent) for use in building construction.
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.
1.3 The committee with jurisdiction over this standard is not aware of any comparable standards published by other ASTM
committees or other organizations.
1.4 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.
1.5 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
2.1 ASTM Standards:
C717 Terminology of Building Seals and Sealants
C1442 Practice for Conducting Tests on Sealants Using Artificial Weathering Apparatus
G151 Practice for Exposing Nonmetallic Materials in Accelerated Test Devices that Use Laboratory Light Sources
3. Terminology
3.1 Definitions—See Terminology C717 for applicable definitions of the following terms: cure, elastomeric, joint, sealant, and
substrate.
4. Summary of Test Method
4.1 Three sealant specimens are spread on aluminum plates and exposed in one of the laboratory accelerated weathering chambers
specified in Section 6 and operated in accordance with specifications in Section 8 and Practice C1442.
1
This test method is under the jurisdiction of ASTM Committee C24 on Building Seals and Sealants and is the direct responsibility of Subcommittee C24.40 on
Weathering.
Current edition approved Feb. 1, 2017May 1, 2023. Published March 2017May 2023. Originally approved in 1975. Last previous edition approved in 20102017 as
C793 – 05 (2017).(2010). DOI: 10.1520/C0793-05R17.10.1520/C0793-23.
2
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
1

---------------------- Page: 1 ----------------------
C793 − 23
4.2 Following this treatment the specimens are exposed for 24 h in a freezer maintained at −26 6 2°C (−15 6 4°F).−26 °C 6
2 °C (−15 °F 6 4 °F).
4.3 At the end of the cold exposure, the specimens are bent over a mandrel within 1 s 1 s at the specified temperature.
5. Significance and Use
5.1 It is known that solar radiation contributes to the degradation of sealants in exterior building joints. The use of a laboratory
accelerated weathering machine with actinic radiation, moisture and heat appears to be a feasible means to give indications of early
degradation by the appearance of sealant cracking. However, simulated weather factors in combination with extension may
produce more severe degradation than weather factors only. Therefore, the effect of the weathering test is made more sensitive by
the addition of the bending of the specimen at cold temperature.
6. Apparatus
6.1 Exposure Apparatus—The exposure apparatus shall be one of the three types of laboratory accelerated weathering devices
described in Practice C1442 that use either xenon arc, fluorescent UV, or open flame carbon arc radiation. Consult Practice C1442,
Section 7 for the differences in test parameters among the devices. Because of differences in test conditions, test results may differ
with the type of device used. T
...