Hardwood Floors June/July 2018

AT THE SITE

RH MOISTURE TESTING IN CONCRETE NOW MUCH FASTER As the result of findings from an ASTM-commissioned study, the ASTMF06 Committee has issued a significant new update to the F2170 Standard for in situ relative humidity (RH) testing in concrete floor slabs. The update changes from 72 hours down to 24 hours as the amount of time needed to obtain official RH readings after drilling test holes.

All images courtesy of Jason Spangler

The change to 24 hours in ASTM F2170 gives just one more reason why the RH test is superior to other moisture testing methods.

virtually the same as those taken later. Based on the study’s findings, one does not sacrifice accuracy or reliability by taking RH readings at 24 hours. These “early” readings, in fact, provide an extremely reliable indication of the true moisture condition of the slab. This new development is significant. Having the opportunity to take earlier readings allows contractors and floor installers to make important decisions related to the installation of flooring much sooner than with other concrete moisture tests.

This is great news if you’re a builder or flooring professional who works with concrete slabs, because you now have the green light to record ASTM-compliant RH readings two full days earlier than previously required by the standard. This important change comes on the heels of an ASTM Precision and Bias (P&B) study in 2014 that demonstrated that test holes for in situ probes achieve moisture equilibrium in just 24 hours. In other words, the ASTMP&B study clearly revealed that “early” readings taken with in situ RH probes at 24 hours are

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