ASTM International recently published its revised ASTM F2170 standard, formally named the “Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes.” ASTM is an international standards organization that has developed and published over 12,000 standards covering a wide range of materials, products, systems, and services.
The updated F2170 standard reduces the mandatory wait period from 72 hours to 24 hours to obtain official, documentable results from an in situ relative humidity (RH) moisture test performed in concrete floor slabs.
This significant reduction in wait time allows contractors and flooring installers to take action on RH test results two days earlier than the standard previously allowed. It also should enable contractors and flooring professionals to accelerate their construction and remodeling projects, according to moisture measurement solutions provider Wagner Meters.
Precision and Bias Study
ASTM updated the industry standard for measuring the moisture condition of concrete slabs in response to an ASTM-commissioned precision and bias (P&B) interlaboratory study conducted in 2014. That study documented the temperature and RH readings of in situ RH probes at various times within the 72-hour window of the older standard, including at the 24-hour mark.
The study’s findings confirmed that the readings obtained at 24 hours were statistically equivalent to readings taken at 72 hours.
“Everyone at Wagner Meters is excited about the change to 24 hours, but we weren’t that surprised,” said Jason Spangler, flooring division manager at Wagner Meters. “Our own internal testing with the Rapid RH system has long shown essentially identical results between the 72-hour and earlier readings.”
“What’s a game changer for flooring professionals is that with the revised F2170 standard,” Spangler added. “They can now take action after just one day instead of having to wait three days. No other industry-accepted test method for concrete moisture offers such fast results, and certainly none are more reliable or accurate than the RH test.”
Standard Supports RH Testing
ASTM first published its F2170 standard in 2002, in response to Scandinavian research that detailed many of the significant advantages of using RH testing to prevent moisture-related flooring failures.
The P&B study results lends further credence to the scientific superiority of RH testing over surface-based moisture condition test methods, according to Wagner officials.
Today, the RH test is shown to be not only more scientifically accurate and reliable, but also more actionable because it provides contractors with usable results in a fraction of the time of other test methods.