ASTM C793-23 PDF

Full title and description

ASTM C793-23 — Standard Test Method for Effects of Laboratory Accelerated Weathering on Elastomeric Joint Sealants. This standard describes a laboratory procedure using actinic radiation, moisture, heat (and optional cyclic bending at low temperature) to evaluate the early degradation (for example cracking and loss of physical integrity) of cured-in-place elastomeric joint sealants used in building construction.

Abstract

This test method provides a controlled accelerated-weathering exposure for single- and multi-component elastomeric joint sealants to indicate susceptibility to solar radiation, moisture and temperature effects. The method is intended to reproduce and accelerate exterior weathering effects in a laboratory setting and to provide comparative performance information between sealants or formulations.

General information

• Status: Active.
• Publication date: May 1, 2023.
• Publisher: ASTM International (American Society for Testing and Materials).
• ICS / categories: 83.060 (Rubber); 91.100.50 (Binders, sealing materials); Book of Standards volume 04.07 (Building seals and sealants).
• Edition / version: C793-23 (designation indicates 2023 revision).
• Number of pages: 4 pages.

Key bibliographic and committee details (designation, DOI, developing subcommittee) are recorded in ASTM’s Book of Standards and related catalog entries.

Scope

This test method covers laboratory procedures for determining the effects of accelerated weathering on cured-in-place elastomeric joint sealants for building construction. It prescribes use of an accelerated-weathering machine (actinic radiation plus moisture and heat) and optional cyclic flexing at cold temperatures to increase sensitivity to cracking; results are intended for comparative evaluations of sealant durability rather than predicting absolute field life.

Key topics and requirements

• Applicability: cured-in-place elastomeric joint sealants (single- and multi-component).
• Test apparatus: laboratory accelerated-weathering chamber (actinic radiation source), moisture spray/condensation, temperature control, and optional cold-box or freezer for cyclic bending tests.
• Specimen preparation: standard specimen dimensions and mounting (frames/plates) as described in the method.
• Exposure cycles: defined radiation, moisture and temperature cycles; optional bending/mandrel flex at specified cold temperature to increase sensitivity to cracking.
• Evaluation criteria: visual examination for cracking, checking for adhesion loss or other degradation; documentation of exposure duration and observed changes.
• Reporting: exposure conditions, specimen descriptions, observations and any deviations from the method.

The method emphasizes comparative ranking and documented test conditions; it does not claim to provide a direct equivalence to any particular outdoor exposure period.

Typical use and users

Used by materials and sealant manufacturers, independent testing laboratories, façade and building-envelope consultants, architects, and specification writers to screen formulations, compare products, and support performance claims for exterior sealants. Test results inform product development, quality control, and specification decisions.

Related standards

Closely associated ASTM standards and practices include other C24 series methods and specifications such as C792 (effects of heat aging on elastomeric sealants), C794 (adhesion-in-peel of elastomeric joint sealants), C920 (Specification for Elastomeric Joint Sealants), and practice C1021 (laboratory practice for sealant testing). These documents are maintained under ASTM Committee C24 (Building Seals and Sealants) and relevant subcommittees.

Keywords

accelerated weathering; joint sealants; elastomeric sealants; actinic radiation; moisture; temperature cycling; bending/mandrel flex; C793-23; ASTM; building seals; durability testing.

FAQ

Q: What is this standard?

A: ASTM C793-23 is a laboratory test method that specifies a procedure for accelerated-weathering exposure of cured-in-place elastomeric joint sealants to evaluate early degradation (for example cracking) caused by radiation, moisture and temperature.

Q: What does it cover?

A: It covers specimen preparation, required apparatus (accelerated-weathering chamber with actinic radiation, moisture, temperature control and optional cold bending), exposure cycles, and visual/physical evaluation criteria for sealant degradation; intended for comparative performance assessments rather than direct field life prediction.

Q: Who typically uses it?

A: Manufacturers, R&D and QC labs, independent test labs, architects, building-envelope consultants and specifiers use the method to screen and compare exterior elastomeric joint sealants.

Q: Is it current or superseded?

A: It is current; the latest revision is C793-23 (published May 1, 2023). Historical earlier editions (for example C793-05, C793-04) exist but the 2023 edition is the active document.

Q: Is it part of a series?

A: Yes — it is part of the ASTM C24 suite of standards for building seals and sealants (developed under Committee C24 and subcommittee C24.40 for weathering). It is commonly referenced alongside related C24 test methods and specifications.

Q: What are the key keywords?

A: Accelerated weathering, elastomeric joint sealant, actinic radiation, moisture, temperature cycling, cracking, durability, ASTM C793-23.