I have the next build-up with water repellent and foil faced PIR in both sides modelled as vapor retarder (sd=1500).
is it right?
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Evaluating the WC in the PIR I have observed irregular, non-periodic changes in the total water content what makes me think that something can be wrong in the results. any thoughts about this change in trend?
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However there are no larger differences in balances as it can also be recognized in part by the total
water content curve above
The steep vertical increases in water content are obviously not correct. However, in the total balances these problem remain unvisible - this may be because the issue is simply a slightly incorrect distribution of moisture within the building component, which is not apparent either in the total water content or in the surface moisture fluxes.
In any case, you can assume that no moisture accumulation will occur between two layers with an sd value of 1500 m. And ss the total error ist only 0,01 kg or 10 g (0,1 kg/m³ * 0,1 m³) over 10 years, the influence on the neighbour materials remains completely negligable.
In other words, to sum up: You can perform a normal evaluation.
best regards
Daniel
Dr.-Ing. Daniel Zirkelbach, Deputy Head of Department Hygrothermics, IBP Holzkirchen
1- Could the "Assessing the Risk of Interstitial Condensation Runoff" guideline be applied for a foil face PIR insulation which is between an unventilated cavity and concrete?
for the case we have unventilated air layer facing in one side with a brick and the other side with a face foil aluminum PIR insulation, which value should we take? the one from the column Rmet to calculate µ* and lambda*?
