There is no correlation between the tests. Relative humidity testing is a measure of moisture condition in the concrete. When a floor covering is placed on top of a slab, it restricts evaporation from the top surface of the slab; moisture within the slab then distributes itself to achieve equilibrium due to temperature and chemical interactions from the top to the bottom of the slab. In the long run, adhesive and flooring are then exposed to the equilibrium moisture condition at the top of the slab. The calcium chloride test does not reflect the long-term moisture situation that will be established by equilibration and can even artificially pull moisture out of the top few centimeters of the slab. Rapid RH^® 4.0 EX Smart Sensors measure the relative humidity that will exist after the floor is covered. See chart on measuring at the correct depth.

For the Flooring Contractor and as part of the project documentation process, ASTM F2170 requires that 3 tests be placed in the first 1,000 sq. ft. and one test be placed every 1,000 sq. ft. thereafter. If you are using the Rapid RH^® 4.0 EX as a monitoring tool early in a project to determine when final acceptance testing should be performed, several Rapid RH^® 4.0 EX Smart Sensors can be placed throughout the floor 28 days after the pour and readings taken as often as desired.

Sensors must have a current, accurate calibration at the time of use to provide trustworthy results. Rapid RH^® 4.0 EX Smart Sensors are supplied with a calibration certificate to prove traceability to the U.S. National Institute of Standards and Technology (NIST) as specified by ASTM F2170 section 6. Reusable moisture probes must be periodically checked or returned to the manufacturer for re-calibration.

Moisture meters should never be used to make the final determination as to whether or not a concrete slab is dry enough for a flooring installation. Here’s why:

No ‘moisture meter’ of any type can give consistently accurate ‘moisture’ readings across the different mixes and densities of concrete. Other components (metal reinforcing bar, aggregate size and amount, etc.) can also cause false indications of ‘moisture’, especially with non-pin meters. Pin-type ‘moisture’ meters are also not practical for moisture measurement because variable chemical and physical characteristics in concrete can cause false readings due to changes in electrical resistance that have nothing to do with moisture.

Even if the so-called ‘concrete moisture meters’ were sufficiently accurate, they only measure ‘moisture’ (not relative humidity) in a very small area near the surface of the concrete slab. This type of surface ‘moisture’ testing says nothing about the conditions inside the slab. Once a floor covering is placed on a concrete slab, the relative humidity (RH) within the slab will equilibrate throughout the thickness of the slab. A slab that may have been “dry” (low RH) at the surface (without a floor covering) will see a higher RH (migrated from within the concrete) at the surface when the floor covering has been installed.

Rapid RH^® 4.0 EX gives a relative humidity reading from within the slab for a much more accurate picture of what the final relative humidity reading will be under an installed flooring covering or coating.

Read more at www.wagnermeters.com/moisture_meters.php

Rapid RH^® 4.0 EX Smart Sensors are installed below the surface of your concrete slab, so there is far less risk of damage to the sensors or interference to normal activity on the floor. Once the Smart Sensors have been placed and equilibrated, future readings can be taken immediately without any further equilibration time. The Rapid RH^® 4.0 EX relative humidity testing system significantly improves your ability to monitor the drying progress of new and existing concrete slabs without adding substantial cost to the project. With the Rapid RH^® Easy Reader, jobsite personnel can easily monitor the drying progress of a slab for any period of time with minimal training. There is no need to have a testing agency return to the jobsite with their instruments to obtain more results.

Anyone who follows ASTM F2170 “Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes.” Once the Rapid RH^® 4.0 EX Sensors’ are installed, jobsite personnel can easily monitor the drying progress of a slab with minimal training. Checklist of steps to follow when taking RH readings.

Rapid RH^® 4.0 EX now features our patent pending Touch-n-Sense™ technology, eliminating the need for specific alignment between the Easy Reader and the Smart Sensor. Simply insert the Easy Reader into any test hole with a Rapid RH^® 4.0 EX Smart Sensor installed, and the two interact on contact. Once the reading has been taken, the data on the Easy Reader will continue to display for up to 5 minutes after being removed from the test hole, simplifying the testing and recording process at the job site.

Touch-n-Sense™ is our patent pending technology, integrated into the Rapid RH^® Easy Reader to enable it to automatically take a reading when placed in contact with the Rapid RH^® 4.0 EX Smart Sensors. Once the bottom of the Easy Reader makes contact with the Smart Sensor, the Easy Reader comes to life, takes a reading and holds it for 5 minutes, even when removed from the test hole, before turning itself off. It’s just that easy.

No. We have completely upgraded our Rapid RH^® 4.0 relative humidity testing system and the new version is not compatible with the previous Rapid RH^®.

The display on the Rapid RH^® Easy Reader will toggle between RH (%) and Temperature readings (°F or °C, depending on the Easy Reader model) for a period of five minutes before it turns itself off.

ASTM F2170 specifies that the floor must be at service conditions (building and room enclosed and the HVAC running). Relative humidity is calculated with temperature, so a significant difference between the temperature of the slab is when testing, and what it will be “in service” is an important consideration. However, relative humidity testing performed 40% below the surface of the concrete is less likely to be affected by the ambient conditions than calcium chloride testing or other surface testing methods, which are affected greatly by ambient conditions.

Yes. The Easy Reader comes with two AAAA alkaline batteries. If battery is low, the display will read "LO." Replace batteries immediately. To replace the batteries, open up the battery cover by removing the one battery cover screw with a jeweler's Philips screwdriver. DO NOT OPEN UP THE FULL BODY OF THE Easy Reader AT ANY TIME.

Rapid RH^® 4.0 EX Smart Sensors should be placed in holes drilled with a carbide-tipped drill bit that falls within the specifications for an ANSI standard ¾” bit. This range is from 0.775” to 0.787”. A tight-fitting Smart Sensor is most likely caused by one of two reasons: The first reason could be that your drill bit has “worn” down with use and has lost some of its “diameter”. This will most likely become noticeable after about 60-70 holes drilled. The other reason could be that you have purchased a new drill bit that is on the lower end of the tolerance spectrum for diameter.

In a few instances, even if you have a properly dimensioned drill bit, the Smart Sensor housing may have been deformed when inserted into the concrete. Deformation is most likely to occur if one does not use the proper insertion tool. Use the Insertion Tool that came with the Rapid RH^® 4.0 EX Complete Starter Kit (also available at the Rapid RH^® 4.0 EX online store) to re-form the Smart Sensor housing by inserting the tool and pressing down to re-shape the Smart Sensor housing. This method works quite well to re-form the Smart Sensor housing to the appropriate dimensions.

No. Each Rapid RH^® 4.0 EX Smart Sensor has an embedded calibration from the factory. The Easy Reader simply displays what the Smart Sensor tells it. That is what makes the Rapid RH^® 4.0 EX Smart Sensor and Easy Reader an intelligent system. Any Rapid RH^® Easy Reader will display the correct value from any Rapid RH^® 4.0 EX Smart Sensor.

The Rapid RH^® Easy Reader may not be properly communicating with the Smart Sensor for the following reasons: (1) The Easy Reader was not in contact with the Smart Sensor long enough. Hold the Easy Reader in the Smart Sensor until the first relative humidity reading appears on the screen, then remove. (2) Debris is blocking proper contact. Check the Smart Sensor housing for any debris. Try twisting the Rapid RH^® Easy Reader gently back and forth a few times to "sweep" away any particles that may have blocked complete contact. If this does not work, vacuum out the housing.