How to perform an in-situ concrete Relative Humidity test as per ASTM F2170

Determine the locations for the ASTM F2170 in-situ RH test

As per ASTM F2170, the in-situ Relative Humidity test requires a hole to be drilled into the concrete slab.

Before drilling, it is necessary to locate the best spot on the slab to perform the test.

This is typically determined by the results of the non-destructive impedance tests, which indicate moisture content values in different areas of the slab. To find out how to perform an impedance test, click here.

Generally, areas with the highest moisture content value are deemed suitable for conducting the in-situ RH test, also known as the concrete humidity test.

Step 2: How to drill holes for the ASTM F2170 test

The holes must be drilled dry and perpendicular (90 ̊), do not use water for cooling or lubrication as this can affect the test results.

The depth of the hole depends on the slab thickness and the drying method:

• When drying is from the top only, drill the hole to approximately 40% of the slab thickness.

• When drying is from both sides, drill the hole to approximately 20% of the slab thickness.

Step 4: Place hole liner

Place the hole liner into the clean holes and seal it with the cap provided.

Leave it for a period of 24 hours to ensure that the heat from drilling does not affect readings.

Step 6: Read RH test results

Remove the cap, connect the interface cable (RHIE2B) to the CMEX5 (or DL-RHTX) and insert the other end of the cable into the Hygro-i2 probe.

Check that readings do not drift by more than 1% RH over a 5 minute period. 

With the Tramex system, it is possible to remove the probe and seal the sleeve for future testing, providing a more reliable and accurate test. 

Please Note: Tramex recommend that the RH probes are not left in-situ for prolonged periods of time when RH values are above 93%. The sensor in the Hygro-i2 probe may take longer to recover if exposed to such readings and can be damaged by prolonged exposure to high humidity. Calibration salts are available to perform on-site calibration checks.