Air infiltration

[guyEANZ]

How do you model air infiltration (from internal environment) in WUFI 2D?
I have a timber frame wall build-up

[Christian Bludau]

The air infiltration model is not yet implemented in WUFI 2D 3.4. An other way could be to use an air exchange source, but you have to assume the values of the air exchange, i do not know any literature about that.
Christian

[Kit Elsworth]

Seeing that the last response on this post was from 2014, I was wondering if there has been an update on air infiltration with WUFI 2D. Can you please confirm that there still does not exist a way to model air infiltration within an wall assembly?

[Christian Bludau]

Dear Kit,

yes, i have to confirm that at the moment. We are working on an upgrade for WUFI 2D, but that will need about one more year.
At the moment you can take in account the air infiltration by combining WUFI Pro and 2D:
1) Calculate your construction with WUFI Pro with air infiltration source included.
2) Export source to file (ASCII-Export)
3) Multiply source values with width of source in WUFI 2D (as in WUFI 2D unit of source is [kg/(m*s)] and in WUFI Pro [kg/(m²*s)], see attached pdf)
4) use source file for calculation in WUFI 2D. The WUFI 2D source should be in the same position as in WUFI Pro.

Christian

[msteinwender]

Hello,

I am posting this as a repost here, because I think "air infiltration" is the way to execute our task and we want to know, what's the up-to-date procedure.

We work with WUFI 2D 4.2 and the task is as following:

We want to simulate a timber-frame-wall (for special room usages) with OSB inside and a ventilated cladding (hinterlüftete Verkleidung) outside in 2 versions:
a) with a vapor barrier inside, and
b) only OSB (without additional vapor barrier). Herefore, the "Luftdurchlässigkeit" of the OSB according to EN 12114 (at 50 Pa pressure difference) of 0,12 m/(m²*h) should be taken into account. How can this be done properly?

Markus

[Christian Bludau]

Hi Markus,

sorry for the late answer, I just found your question.
As the infiltration source still did not find its way into WUFI 2D, the best way would be to do a simulation in WUFI Pro and use the source strength for your 2D simulation, as described above.

Christian

[Barbara]

Hello

I saw the description above but unfortunately I still feel unsecure how to convert the WUFI 1D source the right way into a WUFI 2D source.
I have the following WUFI 1D infiltration source (width 5 mm) which I want to convert into a WUFI 2D source (width 5mm, hight 278 mm):

Source.PNG (103.33 KiB) Viewed 8685 times

Do I have to multiply the WUFI 1D data with 0.005 m or with 0.278 m to get the right unit for the WUFI 2D source?

Thanks a lot for your help in advance.
Greetings,
Barbara

[Christian Bludau]

Hi Barbara,
you have to multiply with the height in your case (278mm).
See also drawing over here:
viewtopic.php?f=15&t=1103#p3166
Best regards
Christian

[Barbara]

Thank s al lot for your fast reply, Christian

Best regards
Barbara