Elcometer 7250 Bedienungsanleitung Seite 5

• Timber adhesive - composite
materials such as plywood will give
artificially high readings due to
adhesive content.
• Homogeneity - different densities
in a material, such as knots in wood
will produce erroneous results.
• Electrical contact - it is important to
maintain good contact between the
pins and the measured substance.
Hard surfaces may require 1.2 mm
diameter holes to be drilled.
• Moisture gradient - the moisture
content of a material may vary across
it's section due to various factors.
• As a general rule of good practice,
results should be obtained from
different areas of the material. If in
any doubt then the (Oven Dry) test
method should be used. A linear scale
is provided for relative measurement,
therefore, facilitating the comparison
of unknown moisture measurements
against known standards obtained by
the (Oven Dry) test method, i.e.:
Wet Weight - Dry Weight x 100 = MC%
Wet Weight
Testing and calibration of our
moisture meters is carried out using
electrical resistance as the basis for
measurement. Standard resistance
values are verified by empirical testing
in accordance with OIML R 92. moisture
meters - verification methods and
equipment: general provisions, issued
by Organisation Internationale De
Métrologie Légale, - 1989.
In conclusion, it must be reiterated that
the meter reading is only a guide as to
the water content of the material under
test. Knowing the actual moisture
content does not indicate whether or
not that a particular material will be
damaged; as different materials can
survive different levels of water content.
A comparison test with a known
sample is always recommended.