material values

[WUFI User]

Hello!

First of all, excuse my poor english skills.
I'm using WUFI 2D 3.3 and i try to make calculations for flat roofs. I checked the material database, but could not find enough materials for my project. Some very common materials like Villas ALGV-45, EPDM-sealing, rubber granulate, ceramic tiles, ... seem to be not in the database.
Am i wrong? If not, where could i get this data from?

My second question is, if it is always necessary to indicate all the characteristic material values like approximation parameters and hygrothermal functions or if it's sufficient to define the basic values. If not, where do i get all the necessary values from?

One more Thing: Can i export the user defined database as a file and import it on another computer?

I would appreciate your help a lot.

Best greetings,
M

[Christian Bludau]

Hello,
for materials like roofing membranes, where mainly the vapor diffusion is important, you can either use an sd-value in the surface coefficients or just change a existing foil and set the wanted water vapor resistance.

For calculation minimum the basic values are needed. For materials like retarders and so on thats enough. If the material can store water, you need a moisture storage function. If you do not have measured values, you also can generate them This can also be approximated from the reference water content and the free water saturation. If you want your material to have an capillary transport you also need Transport Coefficients. They can be generated from the water absorption coefficient. But be careful, always do a sensibility control for the values you use. If there is a high influence in the hydrothermal behavior of certain values, you should try to get some measured values.

Please also press F1 and see what the help is telling...

Database transfer:
At the moment all databases are saved in one file. So easiest way is to find the ibp_24.mdb and replace it on the other computer. For newer installations (this year) the file is located at "\all users\appdata\wufi\database", for older versions it is "\program files\ibp-software\database". But in this case the userdefined materials in the target-database are deleted.
If you want to combine two databases you have to use "dbmaterialpump.exe" in the WUFI tools folder (sorry, it is undocumented, before you use it, make a copy of the destination database (just in case), close all WUFI software, then choose source and destination mdb-file (mda file has to bee in the same folder), unhook "delete userdefined materials" and press "Pump Data")

Christian

[WUFI User]

Hello,

Thanks a lot for your fast reply!
I thought to do so for the foils, and it works fine. I just have a very hard time to find any values of ceramic tiles, for example. Nevertheless, I started to work with WUFI Pro as well. It seems to be easier to understand.
Do you happen to have any link, which i could help me with watercontent and free saturation of ceramic tiles and "Mörtel" and "Zementestrich"?

Best regards,
Martin

[Christian Bludau]

Hello Martin,
for ceramic tiles you also could use an effective sd-value in the boundary conditions, depending if the tiles do have an water uptake or not.
For the Mörtel, open up the catalog "mortar and plaster" (Mörtel und Putz) and you will get displayed all these materials in the source. I would assume that you can use a plaster as mortar, the properties should be quite similar.
If you like to generate an own material, it is always a good idea to use a similar one from the database and change the values... But remember to think about the sensibility of the changes...
For the Estrich got to the catalog "Beton und Estrich", there are two different ones. You have to build them in with all the layers (see info text)
Christian



PS: If you are German, it may be easier to ask you question in German language, you are allowed to do both in our forum. But please use a new thread for that...

[WUFI User]

Hi again!

Thanks, I did create my own materials or used values from similar ones.
For materials like tiles or stone the database does offer basic values, but not the hygrothermal functions or any approximation parameters.
As i want to take account of tile and stone capillarity, i need to define the corresponding values. If you know where to look for this values, it would appreciatet a lot.

Thanks for your time and best regards,
Martin

P.S.:I thought it might be easier for non german speaking users, if i write in english - but perhaps its the opposite

[Christian Bludau]

Hello Martin,

can you specify the construction you like to calculate and the kind of tiles/stones?
The problem with the capillary functions is, that they are highly dependent on the material properties. So it is usually not possible to find a "universal" function for a material.

Christian

[Eduardo]

Christian and Martin,

I run into a similar problem, when tried to create an assembly with an interior tile finish. I could not find tile in the materials data base, so I gather generic information from different sources in the internet and created the material (I gathered: bulk density, porosity, specific heat capacity, and thermal conductivity). Interestingly, when I remove the new tile material from the surface of the wall, and instead use an interior surface transfer coefficient for tile (permeance), the results are completely different. Which way should I go, new material, or just tile at the interior surface transfer coefficient?
I found the data in different sources, not necessarily reliable, but hope the data lets create a very generic, average, material that can help in the simulation. Below are the sources and values I used (sorry about the units):

Bulk Density: 119.9 lbs/cf ------> http://personals.ac.upc.edu/jarnau/2010151.pdf
Porosity: 0.05 cf/cf -----> http://www.avidtiledesign.com/id69.html
Specific Heat Capacity: 0.15 BTU/lb F ------> http://www.engineeringtoolbox.com/speci ... d_154.html
Thermal Conductivity Dry: 0.69 Btu/lb F ------> http://www.new-learn.info/packages/clea ... ivity.html
Permeability: Not Found thus assumed to be a Class I Vapor Retarder (at least over the tile, since it may be different over the grout joint).
Thickness: Assumed to be about 1/2" thick

I hope this helps, and also hope you guys can answer my questions above.

Thanks,

Eduardo

[Christian Bludau]

Hello Eduardo,

there should be the same results, if you use a permeance in the surface conditions or if you instead use a material. Please keep in mind if using a material the value permeability is dependent also on the thickness of the layer, while using the permeance, the thickness already is included.

BTW, there is a value for tiles in the drop-down list for the inner permeance.

Christian