A new ASTM International standard will help manufacturers and regulators better understand how building sealants change once they have been compressed or stretched. The new standard (C1815) was developed by ASTM International’s committee on building seals and sealants (C24).

“Think about the last time you rolled out pizza dough,” says ASTM International member Christopher White, a research chemist at the U.S. National Institute of Standards and Technology. “You would stretch the dough and it would change shape some, but then spring back as well. If you held it stretched out, it would spring back a smaller amount. This is exactly what some sealants do when installed in a building.”

White says that the new standard helps quantify that behavior.

“This is important, as the sealant will fail when the internal stress is greater than the tear strength,” says White. “This standard allows the community to start to understand and quantify the time-dependent response of the sealant.”

The new standard will be used by manufacturers to measure the residual stress in various sealant formulations. In addition, regulators will use the standard to modify existing sealant standards to more realistically incorporate sealant compression behavior.