The brennenstuhl® FM-01 moisture meter displays the moisture content of a material as a percentage by weight. The possible measurement range depends on the selected material mode and ranges overall from 0 to 54.8%.
Important: The displayed percentage value is not a measurement of relative humidity, but refers to the moisture content of the tested material. It is also exclusively a surface-near, local measurement at the point where the measuring pins are inserted or applied to the material. Deeper material layers are not detected.
What measurement ranges apply to the different materials?
Depending on the selected mode, the FM-01 has the following measurement ranges:
- SOFT WOOD: 8.8 to 54.8%
- HARD WOOD: 7.0 to 47.9%
- BUILDING MATERIALS A – Cement mortar layer, concrete: 0.9 to 22.1%
- BUILDING MATERIALS B – Anhydrite mortar: 0.0 to 11.0%
- BUILDING MATERIALS C – Cement mortar: 0.7 to 8.6%
- BUILDING MATERIALS D – Lime mortar, gypsum: 0.6 to 9.9%
- BUILDING MATERIALS E – Brick: 0.1 to 16.5%
The resolution of the meter is 0.1%, and the accuracy specified in the user manual is ±2%.
What reference values does the user manual provide for building materials?
As a guideline, the user manual includes the following moisture limit values at 68 °F (20 °C) and 65% relative humidity:
- Anhydrite mortar: below 0.5%
- Concrete: below 2.2%
- Gypsum: below 0.8%
- Lime mortar: below 2.0%
- Fired brick: below 1.0%
- Cement mortar layer: below 3.0%
- Cement mortar: below 3.0%
These values are guidelines from the user manual. Whether a material is sufficiently dry for a specific purpose can depend on other factors and the particular requirements of the material or construction project.
Why should I measure at multiple locations?
Moisture can be unevenly distributed within a component or piece of wood. For a better assessment, it is therefore recommended to take multiple measurements at different spots and compare the values.
Also, make sure to always use the measurement mode that matches the material. A measurement value can only be meaningfully evaluated if the correct material group is selected.