ASTM C792-23

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Designation: C792 − 15 (Reapproved 2020) C792 − 23
Standard Test Method for
Effects of Heat Aging on Weight Loss, Cracking, and
Chalking of Elastomeric Sealants
This standard is issued under the fixed designation C792; 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 heat aging on weight loss, cracking, and chalking
of cured-in-place elastomeric joint sealants (single- and multi-component) for use in building construction.
1.2 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.
1.3 There is no known ISO equivalent to this test method.
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:
C717 Terminology of Building Seals and Sealants
3. Terminology
3.1 Definitions—See Terminology C717 for definitions of the following terms used in this test method: compound, elastomeric,
non-sag sealant, sealant, standard conditions, and self-leveling sealant.
4. Summary of Test Method
4.1 Three sealant specimens are spread on thin aluminum plates and, after determining net weights of sealant, are cured for 7 days
at Standard Conditions.standard conditions. Immediately following this initial cure time two specimens are exposed in a
forced-draft oven maintained at 70 6 2°C (1586 3.6°F) 70 °C 6 2 °C (158 °F 6 3.6 °F) for 21 days. At the end of this exposure
the percentage weight loss of the sealant is determined and examination is made for presence of cracks and chalking.
This test method is under the jurisdiction of ASTM Committee C24 on Building Seals and Sealants and is the direct responsibility of Subcommittee C24.20 on General
Test Methods.
Current edition approved Jan. 15, 2020May 1, 2023. Published February 2020May 2023. Originally approved in 1975. Last previous edition approved in 20152020 as
C792 – 15.C792 – 15 (2020). DOI: 10.1520/C0792-15R20.10.1520/C0792-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
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C792 − 23
5. Significance and Use
5.1 Weight loss through volatilization of components of a sealant in a building joint may affect sealant appearance because of
shrinkage, and sealant performance because of the loss of functional sealant components. Exposure to high-temperature
environments will accelerate the loss of volatiles.
5.2 This test method measures weight loss. It can be used in combination with a knowledge of sealant density to estimate
shrinkage. In addition, when compared to sealant theoretical weight solids, it provides an estimate of the extent to which functional
sealant components can be volatilized when exposed to high service temperatures. Substantial losses of this type may help predict
early failures in durability. Also, development of cracks or chalking, or both, lessens sealant service life. However, a sealant that
develops no cracks or chalking, or low weight loss in this test method, does not necessarily assure good durability.
6. Apparatus
6.1 Forced-Draft Oven, controlled at 70 6 2°C (158 6 3.6°F).70 °C 6 2 °C (158 °F 6 3.6 °F).
6.2 Balance, sensitive to 0.01 g.
1 1
6.3 Rectangular Brass Frame, with inside dimensions 130 by 40130 mm by 40 mm by 6.4 mm (5(5 in. by 1 ⁄2 in. by ⁄4 in.). in.).
6.4 Aluminum Plates, three, each 152 by 80 by 0.6 to 1.6 mm (24 152 mm by 80 mm by 0.6 mm to 1.6 mm (24 gauge to 16 gauge).
6.5 Straightedge, metal or plastic, about 152 mm (6 in.) long.
6.6 Thin Knife Blade.
6.7 Spatula, steel, about 152 mm (6 in.) long.
7. Procedure
7.1 Unless otherwise specified by those authorizing the test, standard conditions of temperature and relative humidity for the test
shall be found in Terminology C717.
7.2 T
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