typical build-in moisture

Everything that didn't fit in any other topic
Post Reply
jorne
WUFI User
WUFI User
Posts: 25
Joined: Sat Oct 17, 2009 3:56 am -1100

typical build-in moisture

Post by jorne »

Hi

In the menu : " Initial Conditions", have a choice: assign Typical build-in Moisture, when i choose the option : " in each layer". What is mean it? What is typical build-in moisture? i try to find at help, but I did not found anything about it.

regards
Manfred Kehrer
WUFI International Support Team
WUFI International Support Team
Posts: 351
Joined: Thu Mar 10, 2005 2:17 am -1100
Location: Northbrook, IL; USA
Contact:

Post by Manfred Kehrer »

Dear Jorne,

typical built in moisture can be set for each material in the material properties. This is normally the water content at 80% RH, except for material which are mixed with water e.g. masonry stones, plasters, ...

If you press "Assign Typical build-in Moisture" then these values from the material properties of each material will be copied into the Initial Water Content Column.
Manfred
Wiss, Janney, Elstner Associates, Inc.
Official WUFI® Collaboration Partner for USA/Canada
Enjoy WUFI® :) .... It is easy and complex.
Axelarris
WUFI User
WUFI User
Posts: 24
Joined: Tue Mar 25, 2014 5:44 am -1100

Re: typical build-in moisture

Post by Axelarris »

I am confused about the Typical Built-in Moisture. You seem to be saying that this value is the equilibrium moisture content of each material at 80%RH. However, when I use "Constant Across Component" and set RH = 80% (default), isn't that also providing the equilibrium moisture content of each material at 80%RH?
I am gettting very different values when I use these two different approaches, so they do not seem to be the same. For example, Gypsum Board (USA) has a water content of 0.39 lb/ft^3 when the "Constant across component" is used with 80% RH. But when I use "In each Layer" and click "Assign Typical Built-In Moisture", the Gypsum Board (USA) has a water content of 2.185 lb/ft^3. That is more than 5 times as much!! What is going on?
Also, what is the difference between Gypsum Board (USA) and Interior Gypsum Board - they have very different Built-in moisture content values? Thank you.
Christian Bludau
WUFI SupportTeam IBP
WUFI SupportTeam IBP
Posts: 1160
Joined: Tue Jul 04, 2006 10:08 pm -1100
Location: IBP Holzkirchen, the home of WUFI
Contact:

Re: typical build-in moisture

Post by Christian Bludau »

Dear Axelarris,

the typical build in moisture is the moisture which is theoretically in the freshly built up construction, taking in account the water for mix up the material (eg concrete, mortar).
For other materials it is at the equilibrium moisture at 80%. Thats the material not build in using additional water like gipsum board, wooden materials.
And then there are the materials not taking up much water from the humidity they are stored in. For that materials you can assume a build in moisture of zero (eg. Foamglas, Membranes, EPS)...

For the gypsum board in the Fraunhofer source a water content at 80% is given for the build in moisture. For the gipsum board USA it is at 97%. Maybe there is the water taken in account, which can get into the board by some finish render???
I think the value at 80% would be more realistic here.

Christian
Post Reply