Shell Limestone (Muschelkalk) as a cladding

[PScharfA]

Dear WUFI people,



currently there seems to be just one option for Shell Limestone (Muschelkalk) in WUFI.
We often find listed buildings with these claddings (at least here in Germany). The natural stone cladding is often times d = 50 mm thick and sits in a for example d = 20 mm mortar bed.

The component in the WUFI Dataset is "Krensheimer Shelly Limestone"

Unfortunately it shows no data in "Liquid Transport Coefficient, Suction:


How is such a component considered within the calculation? Does it still make sense to use it, or not since a crucial parameter seems to be missing.

It could be one option to unlock it and generate data from approximation parameters but therefore you would need to measure it in advance.
Is there another way?

Thank you all! Greetings

[Thomas]

Hi PScharfA,

I consulted the original data sheet from which the Shell Limestone data for the material database were taken, and it has no liquid transport coefficients either. (So these coefficients have not been lost at some point - they never existed.)

The reason may be explained by the note "extreme variation in material properties". It seems that liquid transport coefficients have been measured, but apparently it was not found useful to report data which could potentially be very misleading if the building for which the simulation is done has a different kind of Krensheimer which may behave very differently.

I agree that this incomplete data set is not very useful for an exterior cladding - I don't know if Krensheimer is used for indoor spaces where there is no rain but where it might still be of interest to investigate vapour diffusion...

What you could do is this: Create a series of Krensheimer clones, with liquid transport coefficents "generated" for a series of A-values within a plausible range. If simulations with these test materials show that no problem occurs in any case, then you are fine. If the simulations show that problems occur for a certain range of A-values you will have to investigate whether the A-values of the limestone on your object is within this range.

This kind of procedure which uses test simulations to investigate the "sensitivity" of simulation results with respect to some parameter is always recommended if there are unknown or poorly known parameters. Please see also the section "Uncertainties" in the topic "Assessment Criteria" of the help file:

Appendix | Assessment Criteria

Kind regards,
Thomas