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= Diffusion Resistance Factor, Moisture-dependent =


The [[Details:BasicMaterialData|diffusion resistance factor
(µ-value) of the dry material]] is a basic material parameter
and thus indispensable. If, in addition, the dependence of the
diffusion resistance factor on the moisture content must be taken
into account, WUFI can optionally employ a table with the relevant
data. WUFI interpolates linearly between table entries.


Please note, however, that in mineral building materials the
(fictitious) decrease of the diffusion resistance factor with
increasing moisture content is due to surface diffusion [1] and
may therefore also be included in the capillary conduction. In
this case, using a constant diffusion resistance factor and
choosing appropriate [[Details:LiquidTransportCoefficients|liquid
transport coefficients]] is more advisable.


During the calculation WUFI performs iterations where it samples
small regions of the tabulated curve. Very sharp bends in the curve
may throw the iteration off and thus impede its convergence. In
such a case, the curve should be smoothed by inserting additional
points. A large number of entries may slow the search in the
table, however.


The definition of the diffusion resistance factor (µ-value)
is discussed in the topic [[Details:WaterVaporDiffusion|Water
Vapor Diffusion]].


Even if you do not explicitly use a moisture-dependent diffusion
resistance factor, WUFI will treat it as moisture-dependent if the
moisture content exceeds the free saturation wf.
For details see the discussion of the
[[Details:BasicMaterialData|Diffusion Resistance Factor Dry]].


Literature:

<TABLE>
<TR><TD VALIGN="TOP">[1]</TD><TD>Krus, M.: Moisture Transport and
Storage Coefficients of Porous Mineral Building Materials.
Theoretical Principles and New Test Methods 
Fraunhofer IRB Verlag, 1996</TD></TR>
</TABLE>

Details:DiffusionResistanceFactorMoistureDependent - Versionsgeschichte

AntretterF: Die Seite wurde neu angelegt: = Diffusion Resistance Factor, Moisture-dependent = The diffusion resistance factor (µ-value) of the dry material is a b...

AntretterF: Die Seite wurde neu angelegt: = Diffusion Resistance Factor, Moisture-dependent =
The diffusion resistance factor (µ-value) of the dry material is a b...