Astm C 920

is the industry-standard specification for elastomeric joint sealants used in building construction. It serves as a benchmark for performance, ensuring that sealants can withstand the dynamic stresses of thermal expansion, moisture, and mechanical loads. 1. Scope and Core Purpose

Detailed technical documents and test reports can be found through resources like Euclid Chemical , Soudal , and Scribd . astm c 920

| Spec Code | Translation | Common Application | | :--- | :--- | :--- | | | Stretchy, Non-Sag, No Traffic | Standard vertical wall expansion joints, window perimeters. | | Class 25, Grade P, Use T | Stretchy, Self-Leveling, Traffic | Parking garage floor joints, sidewalks. | | Class 12.5 | Low Movement | Small gaps, static joints (less common in modern high-performance specs). | | Type M | Multi-Component | Large projects (like airports/malls) where fast cure and high durability are needed. | | Type S | Single-Component | General construction, smaller jobs, easy repair work. | Scope and Core Purpose Detailed technical documents and

: Measuring the cured sealant's resistance to indentation. | | Class 12

: Self-leveling; typically for horizontal joints. NS (Non-sag) : Gunnable; for vertical or overhead joints.

A compliant sealant label will read like: