Rapid RH® L6 and Smart Sensor Installation

How to Install Rapid RH Steps

In Situ Concrete Testing Steps

Step 1: Drill the Hole

Correct hole depth and hole diameter are important in complying with the ASTM F2170 standard. Drill a hole in the concrete slab to the required depth using a rotary hammer drill and a ¾”-diameter masonry drill bit. Per the ASTM F2170 standard, drill the hole to a depth equaling 40% of the slab’s thickness for slabs that are drying from one side, or 20% depth for a slab drying from two sides.

Step 2: Clean the Hole

Attach the vacuum attachment to the straight extension of a shop vacuum cleaner hose* and thoroughly vacuum up the dust in and around the hole.

Next, insert the wire bristle brush into the hole. Turn the brush several times to loosen pulverized concrete from the walls of the hole. Vacuum again. Repeat this step twice to ensure no loose concrete particles remain in the hole.

IMPORTANT — Correct Diameter and Hole Uniformity: Use the ¾”-diameter section of the black Smart Sensor Insertion Tool as a diameter and uniformity gauge to ensure a correct and uniformly round hole. Not performing this step may cause damage to a Smart Sensor when attempting insertion.

*The vacuum attachment may require an adapter depending on vacuum model.

Step 3: Verify the Smart Sensor

Before inserting the Rapid RH L6 Smart Sensor, it is recommended that you confirm the L6 Smart Sensor is functional by quickly taking a reading while holding the L6 Smart Sensor. You can do this by simply inserting the Total Reader® into the L6 Smart Sensor and confirming that the Total Reader displays temperature and RH numbers approximate to the open air space where you are located.

Step 4: Insert the Smart Sensor

First, be sure you choose the system of Rapid RH Smart Sensors that makes the most sense for your application. Wagner Meters offers both the Rapid RH L6, for ease and simplicity of use, and the Rapid RH 5.0, for those who prefer a reusable RH sensor.

Each Smart Sensor pack includes ten (10) short (0.4”) extensions that can be inserted into the Smart Sensor barrel to enable use in thicker slabs. Adding one insert extends the Smart Sensor barrel length to 2” for testing 5”-thick slabs to the 40% depth.

For all installations, take the Smart Sensor directly out of the package, and with no extensions installed, insert the Smart Sensor into the hole using the insertion tool with the cap placed atop for ease in pushing down on the insertion tool. Push down on the insertion tool with the cap to force the Smart Sensor down inside the hole, “seating” it at the bottom.

Once installed, for 1.6” depth holes (40% of 4”), insert a protective cap into the top of the Smart Sensor base sleeve, and push down to the concrete surface. Or, if testing in thicker slabs, assemble the proper number of extensions, and with the protective cap inserted into the topmost extension, push down the extensions and cap into the hole to the concrete surface, until fully seated on the Smart Sensor, completing the installation.

Caution: NEVER use the Total Reader to install the Smart Sensor.

STEP 5: Take Readings

When ready to take readings, remove the protective cap from the Smart Sensor. Insert the Rapid RH Total Reader firmly until it comes fully into contact with the bottom of the Smart Sensor. Hold the Total Reader in place until the first RH reading appears on the screen (about three seconds), then immediately remove the Total Reader. The display will toggle back and forth between the RH value (when the cursor is next to the %RH symbol) and the temperature value. Once the Total Reader is removed from the Smart Sensor, the readings from that Smart Sensor will continue to display for approximately 5 minutes or until the Total Reader is reinserted into another Smart Sensor. After removal, wait at least 5 seconds before inserting the Total Reader into another Smart Sensor.

After the initial equilibration has been reached per ASTM F2170 requirements, subsequent readings can be taken instantly. If future testing is needed, replace the protective cap by snapping it back into the Smart Sensor.

Record readings on the report form in the spaces provided for information required by ASTM F2170, including the date, time, %RH and temperature. Or to enjoy added convenience and data integrity, be sure to check out the new Rapid RH Total Reader and the DataMaster L6 app. When paired with your smartphone or another mobile device, they offer you a powerful array of read, record, and report functions.

Once you have obtained RH readings, you’ll need to evaluate the slab’s readiness for the flooring installation. For additional questions related to what RH levels are appropriate, please contact the manufacturer of the product to be applied to the concrete slab.


Learn how to use the Rapid RH L6 for concrete moisture testing


  • Rapid RH Test Results Form
  • ASTM F2170 Checklist
  • Concrete In-Situ Relative Humidity and pH Test Spec
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