More on Moisture: Do Both Tests
Larry Press, director of flooring for Helmitin Adhesives, is no stranger to installation standards. He has been involved with ASTM International since 1987 and sits on numerous committees and subcommittees related to adhesives, VOC emissions and evaluating moisture content in concrete. It’s that last one that led to a phone call with Larry recently.
He was responding to my editorial from the March issue, “When Testing a Flooring Job, Use Multiple Data Points.” In that editorial, I noted that Sonny Callaham of Divergent Adhesives had made a provocative statement about ASTM F2170 when we sat on a panel together. Sonny said that one of the reasons moisture issues are more prevalent today is that contractors are relying on F2170 alone instead of multiple data points.
Let’s back up. The two moisture tests recognized by the industry are ASTM F2170 (also known as the “RH test” or “in-situ probe test”) and ASTM F1869 (aka the “calcium chloride test”). Both tests measure different things: F2170 measures relative humidity, while F1869 measures moisture vapor emission rate. While most contractors will choose one test (if they choose any), most industry experts agree that the best approach for getting a complete picture of the moisture situation is to perform both tests.
Now Larry has gone on record with the same sentiment. He said that since moisture readings vary between manufacturers, someone conducting tests with multiple brands of meters will get inconsistent results. Performing both tests will help ensure that discrepancies are caught.
Additionally, in an email earlier this year to the ASTM Committee F06 on Resilient Floor Coverings, Press wrote that he is uncomfortable using F2170 testing alone since the short- and long-term effects of resilient flooring placed in various RH conditions have not been evaluated.
This does not mean you should never perform the F2170 test in a resilient installation again. You need to remember that Larry is steeped in the protocol of standards writing—and in the language of standards, results need to be consistent, repeatable and backed by a mountain of data. From his point of view, until every ‘i’ is dotted and every ‘t’ is crossed, the standard does not bear up to scrutiny. And I am definitely sympathetic to that point of view.
In the real world of fast-track jobs and constant production, however, where manufacturers spell out which test to use, it’s not realistic to wait for a standard to know how to be most efficient at your job. So, while Larry and his colleagues work on these issues from behind the scenes, just know that if you want to be as safe from liability as possible, take the time to perform both tests. And if you have any questions, reach out to the technical support lines of the flooring manufacturer, the adhesive manufacturer and—if applicable—the moisture meter manufacturer.