Astm C920 »

: How well the sealant sticks to various substrates.

Now, imagine you are sealing a .

This is perhaps the most critical spec. The "Class" number indicates the joint movement capability expressed as a percentage of the joint width. astm c920

: Gunnable sealants that stay in place, making them suitable for vertical or sloped joints. : How well the sealant sticks to various substrates

In the complex choreography of modern construction, where steel, glass, concrete, and wood must move, breathe, and endure together, the humble sealant often plays the role of unsung hero. While structural elements bear the loads, sealants bear the strain of the environment—expanding with summer heat, contracting with winter cold, and repelling wind-driven rain. But not all sealants are created equal. For engineers and contractors tasked with keeping skyscrapers watertight and bridges durable, one standard stands as the definitive benchmark for high-performance elastic joints: The "Class" number indicates the joint movement capability