Astm C920 ((new)) -

Compliance reports, such as those found on Scribd or provided by manufacturers like Silicones for Building , measure several critical properties: C920 Standard Specification for Elastomeric Joint Sealants

If a joint is expected to expand and contract significantly due to thermal changes, a Class 12.5 sealant will tear. A Class 25 is the industry standard for most vertical and horizontal construction. astm c920