ASTM C920 is the ASTM standard for elastomeric joint sealants, providing a clear technical basis for evaluating sealant products used in joints and related construction applications. It helps define the expected characteristics of these materials so purchasers, specifiers, and manufacturers can compare products more consistently. By focusing on the performance and classification of elastomeric joint sealants, this specification supports more reliable selection, quality control, and compliance in procurement and project documentation.

Purpose of ASTM C920

The purpose of ASTM C920 is to establish a standard specification for elastomeric joint sealants, helping define how these materials are identified and assessed for use. In practical terms, it gives the construction and materials community a common reference for product evaluation, specification writing, and acceptance decisions. ASTM C920 is useful when a project needs a consistent way to compare sealant performance expectations rather than relying only on product names or general claims.

Common use cases of ASTM C920

ASTM C920 is commonly referenced when selecting or specifying sealants for joints in building and construction assemblies where elastic movement accommodation is important. It may be used in procurement documents, technical submittals, product data reviews, and quality control checks for sealant products. Because the standard focuses on elastomeric joint sealants, it is especially relevant when compatibility, durability, and performance classification matter during project planning and material approval.

Why ASTM C920 matters

This standard matters because it gives buyers and specifiers a dependable way to evaluate elastomeric joint sealants against a recognized ASTM framework. That helps reduce ambiguity during product selection, supports more consistent testing and documentation, and can lower the risk of using a sealant that does not fit the project requirements. ASTM C920 also helps align manufacturers and project teams around the same technical expectations, which is important for compliance and quality assurance.

• Standard specification for elastomeric joint sealants
• Supports product comparison and technical review
• Useful for procurement and submittal documentation
• Helps guide compliance and quality control
• Relevant to joint sealant selection and evaluation