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6.4 Material specific calibration and moisture index
The sensing heads MOIST-PM V2 and MOIST-R1M V2 are material specific calibrated.
The calibration curves were generated in the moisture laboratory of hf sensor very
carefully.
At the moment calibrations are available for these materials:
- Brickwork new (density 1.6 ... 1.8 g/cm³)
- Brickwork old (density 1.1 ... 1.3 g/cm³)
- Clinker
- Wood (pine, spruce)
- Calcareous Sandstone
- Porous Concrete
- Sandstone
- Gypsum Floor (MOIST-R1M V2 and MOIST-R2M V2 only)
- Cement Floor (MOIST-R1M V2 and MOIST-R2M V2 only)
Other calibration curves will be added gradually following the progress in hf sensor’s
internal calibrations. Calibration curves can also be added customer specific. Hf sensor
will have great pleasure to offer such customer specific calibrations.
The material specific calibration is only valid for homogenous materials which have the
required minimum volume (→ 6.3). If the main constituent of a test object is known,
measurements will also be possible through thin surface layers (for instants plaster)
without significant falsification.
In real applications, building materials must be considered to be inhomogeneous. This
inhomogenity can be in the material itself or can correspond to the materials water
binding mechanisms or to the moisture distribution in the material.
That’s why measuring in such test objects always requires averages to be generated
from single measurements to get the required significance.
For the realisation of measurements in materials, whose calibration curves aren’t
known, and for relative measurements - for instance lateral moisture distributions -
Moisture Index can be used. Moisture Index is a dimensionless number between 0 and
4000.
Under the conditions described in 6.3 low Moisture Index means low water
content and high Moisture Index means high water content.
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