Hello everyone,
I am new to WUFI 2D and have a couple of questions about default assumptions and result interpretation. I have already reviewed the WUFI 2D example PDF, but I am still unsure how to apply the guidance to my case.
For the default Initial Conditions, is it generally acceptable to leave the default values as they are, or should they be adjusted for each material? If they should be adjusted, what is the recommended way to define material-specific initial moisture/temperature conditions?
After running the simulation, what are the key outputs I should review to confirm that the results are reasonable? For example, should I focus on total water content, material-specific water content, relative humidity/temperature at monitoring points, drying potential, or year-to-year moisture accumulation?
Any practical guidance, examples, or beginner-level checks would be greatly appreciated.
Thank you.
WUFI 2D - General question
-
Christian Bludau
- WUFI SupportTeam IBP
- Posts: 1276
- Joined: Tue Jul 04, 2006 10:08 pm -1100
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Re: WUFI 2D - General question
Initial conditions:
In many cases, it is acceptable to use the default initial conditions (e.g. around 80 % RH and 20 °C), especially if no better information is available. These values represent a reasonable approximation for materials close to equilibrium moisture conditions.
If you have specific information (e.g. built-in moisture, wet masonry, or very dry materials), you can define layer- or material-specific initial conditions. Otherwise, the default values are typically sufficient, as the system will adjust towards its dynamic equilibrium during the first simulation years.
Result evaluation:
More important than individual values is a consistent and structured evaluation of the results. The following checks are recommended:
Total water content:
Check whether the moisture content stabilizes over the years (seasonal variation is normal). A continuous increase indicates moisture accumulation.
Moisture balance / convergence:
Always verify numerical quality first (balances, convergence), before interpreting results.
Critical materials / locations:
Evaluate water content or relative humidity in critical layers or positions (e.g. cold side, interfaces, corners in 2D).
Limit values:
Depending on the materials, assess risks such as mould growth, condensation, frost, or increased thermal conductivity.
Year-to-year development:
The construction should reach a stable, repeating annual behaviour (dynamic equilibrium). A deviation of less than about 1 % per year is typically considered stable.
As a general rule, WUFI results should not be interpreted based on a single curve alone, but by combining moisture balance, critical values, and engineering judgement.
More information on the evaluation can be found in our Guideline for the evaluation and assessment of hygrothermal calculation results:
https://wufi.de/en/service/downloads/#result_evaluation
Christian
In many cases, it is acceptable to use the default initial conditions (e.g. around 80 % RH and 20 °C), especially if no better information is available. These values represent a reasonable approximation for materials close to equilibrium moisture conditions.
If you have specific information (e.g. built-in moisture, wet masonry, or very dry materials), you can define layer- or material-specific initial conditions. Otherwise, the default values are typically sufficient, as the system will adjust towards its dynamic equilibrium during the first simulation years.
Result evaluation:
More important than individual values is a consistent and structured evaluation of the results. The following checks are recommended:
Total water content:
Check whether the moisture content stabilizes over the years (seasonal variation is normal). A continuous increase indicates moisture accumulation.
Moisture balance / convergence:
Always verify numerical quality first (balances, convergence), before interpreting results.
Critical materials / locations:
Evaluate water content or relative humidity in critical layers or positions (e.g. cold side, interfaces, corners in 2D).
Limit values:
Depending on the materials, assess risks such as mould growth, condensation, frost, or increased thermal conductivity.
Year-to-year development:
The construction should reach a stable, repeating annual behaviour (dynamic equilibrium). A deviation of less than about 1 % per year is typically considered stable.
As a general rule, WUFI results should not be interpreted based on a single curve alone, but by combining moisture balance, critical values, and engineering judgement.
More information on the evaluation can be found in our Guideline for the evaluation and assessment of hygrothermal calculation results:
https://wufi.de/en/service/downloads/#result_evaluation
Christian