EN
Operating manual – Material moisture measuring device T510
12
Sorption isotherm of plaster:
This was also confirmed by the calibration measurements of the
Institute of Building Materials Research (IBAC). Therefore, one
can conclude, that a direct correlation between measured value
and mass-related moisture content is not possible.
As sufficient criterion for the classification of the measured values
it can however be stated, that plaster can be considered dry,
when the measured resistance value is smaller than 30 digits.
When evaluating the measured values it is imperative to observe
that different marginal conditions prevail for every measurement.
Important variables influencing the worth of the measured value
are the connection of the electrodes to the material to be meas-
ured, the material temperature, the construction material's com-
position, salt loading and aggregates.
For construction materials not listed, usually sufficient conclu-
sions can be drawn owing to local reference values. As a conse-
quence, the affected damp area can be narrowed down to such
an extent that a comparative measurement is carried out at an
evidently dry wall or floor area as basis of valuation.
By use of the higher measured values of the area to be assessed,
the spreading of the damp area can well be determined.
Reference values for the assessment of areas damaged by
water
In case of water damage a resistance measurement can be car-
ried out to enable an evaluation of the area to be dried. Based on
the factual moisture content and the changeable marginal condi-
tions, the following table can be used to assess the necessity for
drying by use of technical means.
Here, one has to observe that the measurement results constitute
only one component of a comprehensive damage diagnosis. The
experience of the evaluator and local circumstances play just as
vital a role as the documentation of the measurement results. The
documentation further allows to demonstrate the success of a
technical drying procedure.
1,5
1,0
0,5
0
0
0,2 0,4 0,6 0,8 1,0
relative humidity ψ
water content
u
V
in %
Digit scale values
*
**
***
Insulation layers / packed bed
polystyrene (particle foam)
< 36
36 to 50
> 50
polystyrene hard foam (extruded)
< 36
36 to 50
> 50
polyurethane hard foam
< 36
36 to 50
> 50
glass fibre
< 36
36 to 45
> 45
rock wool or slag wool
< 36
36 to 45
> 45
silicate foam glass
< 36
36 to 50
> 50
cork, expanded volcanic rock
< 31
31 to 40
> 40
wood-wool slabs
< 41
41 to 50
> 50
clay fill
< 41
41 to 55
> 55
coir
< 36
36 to 40
> 40
Construction materials
anhydrite screed
< 36
36 to 50
> 50
cementitious screed
< 36
36 to 50
> 50
wood cement screed
< 36
36 to 50
> 50
xylolith
< 41
41 to 55
> 55
plaster
< 31
31 to 40
> 40
*
dry
– no drying required
**
threshold
– drying may be required after evaluation of the damage
characteristics
***
thorough moisture penetration
– drying by use of technical means
required
All values are approximations and without warranty.