WUFI

Dear all WUFI users,

I'm trying to model a wall, where one of the layers is a steel sheet. Because of the issue that there are several steam-tight layers in this construction, we need to make a hole in the steel sheet to allow the wall to dry out The purpose is to find out how big and how many holes (how many percent perforation) I need in the steel plate so that the moisture in the wall is able to dry out. Do anyone have any suggestions on how to solve this? Is there a layer in the program that is a perforated steel sheet?

Thank you in advance,

Anna Eknes

Hi Anna,

In the North American Database there is a material called 'Metal perforated' which may be of use.

Unfortunately the material information section is silent about the proportion of metal that is perforated. An on line search for the source reference: "ORNL/CON-380" reveals nothing.

In a somewhat dated reference: Seiffert, K. (1970). Damp diffusion and buildings. Prevention of Damp Diffusion Damage in Building Design there is some information which may be relevant: 1.5mm thick aluminium sheeting perforated with 2.5mm diameter holes:

26 holes/m2 - 6195 diffusion resistance factor (mu-value)
56 ditto - 1345 ditto
112 ditto - 610 ditto

Regards

Peter