Does temperature affect the accuracy of a wood moisture meter reading?
The short answer is yes, but usually to a very small extent in needle gauges. As the temperature of the wood increases, its resistance decreases, resulting in an increase in the indicated% MC of the sample. For on-site conditions, if the temperature of the tested wood sample is between 50 ° F (10 ° C) and 90 ° F (32.2 ° C), there is no need to calibrate the temperature reading results.
When measuring wood materials beyond these temperature values and the instrument itself does not have built-in temperature calibration, you can use a temperature calibration chart to find the calibration (Delmhorst provides these calibrations for each hygrometer).
Needle free measuring instruments do not measure resistance, so their readings are not affected by the temperature of the wood unless the sample is completely frozen.
How to correct the readings of different types of wood?
Using needle and needle free moisture meters, the type of wood will affect the readings you obtain. For needle instruments, the difference in readings is due to the different inherent resistance characteristics of different types of wood. For needle less instruments, the specific gravity (SG) of wood can affect the reading results.
Each hygrometer is typically calibrated using a specific type of wood, such as Douglas fir or oak, which makes the instrument accurate when measuring that type of wood, but less accurate for other types of wood.
Usually, there are two methods to correct the readings of a given type of wood:
Use the species calibration table provided by the instrument manufacturer.
Use instruments with built-in species calibration.
Using instruments with built-in calibration functions is usually easier and faster than referring to manuals and performing mathematical calculations on your own.
