New NIST Testing Device May Help to 'Seal the Deal' for Building Owners

From NIST Tech Beat March 15, 2011
Contact: Mark Bello
(301) 975-3776

Just as a chain is as strong as its weakest link, a building is as secure against the environment as its most degraded joint sealants, about 50 percent of which fail in less than 10 years after installation.

Mounted on the roof of a building on NIST’s Gaithersburg, Md., campus, this NIST-developed device is designed to induce temperature-caused strains on sealant specimens while monitoring loads and displacements. Affixed to a rigid base, the top segments of PVC pipe expand and contract with changes in temperature. Sensors, load cells, and specimens--sandwiched between aluminum blocks--are suspended from the top crosspiece, which moves, and are attached to the same rigid base. Credit: NIST View hi-resolution image

The upshot for U.S. homeowners is that moisture damage due to failed sealants is responsible for much of the $65 billion to $80 billion they collectively shell out for house repairs annually.
Researchers at the National Institute of Standards and Technology (NIST) are assembling a toolkit of measurement devices and scientific data that will help manufacturers of sealants systematically improve the protective performance of their products. Their latest contribution, described in the current issue of the Review of Scientific Instruments,* is an outdoor testing system that tracks real weather conditions—by the minute—and measures the squeezing and stretching that occur in sealants as the building moves with temperature changes.

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