Astm C920 Jun 2026

The core of ASTM C920 lies in its classification system, which revolves around a critical variable: . The standard designates sealants by a grade (P for self-leveling/pourable, T for gun-grade/thixotropic), a class (indicating the expected movement, typically ±12.5% to ±50%), and a use (T for traffic, NT for non-traffic, A for metal, O for other substrates). For example, a sealant labeled ASTM C920, Grade T, Class 25, Use NT signifies a non-sag gun-grade product capable of accommodating 25% movement (either extension or compression) in a non-traffic joint. This alphanumeric code is the Rosetta Stone of joint design, allowing a specifier in New York to trust that a sealant made in Ohio will perform predictably in a Seattle parking garage.

, officially titled the " Standard Specification for Elastomeric Joint Sealants ," is the primary performance standard used in the construction industry to evaluate and classify sealants. It establishes the minimum performance requirements for single- or multi-component cold-applied elastomeric sealants used in building joints. Why ASTM C920 Matters astm c920

This defines the environmental exposure the sealant can withstand. The core of ASTM C920 lies in its

The number is vital because it indicates the percentage of movement the sealant can handle. Class 12.5 : Handles ±12.5% movement. This alphanumeric code is the Rosetta Stone of

Using Grade P (Pourable) on a vertical wall will result in a mess and a wasted product, as the liquid will flow out before it cures. Conversely, using Grade NS (Non-Sag) in a horizontal traffic joint creates a bump in the road that can be tripped over or peeled away.