basement modelling

[p_sentobe]

Hi,
when modelling a basement zone for purposes of SBEM/NCM does ModelIT automatically assign the walls as being adjacent to ground?
The model browser does not show any change in colour for those particular envelops - they are all yellow for external.

The zone is definitely 'underground' as it is below the green horizon when viewed in the model viewer.

Thanks in advance.

[Complex Potential]

Hi Sentobe

I don't think Compliance or Apache assumes walls are ground contact by default even if it is below the 0 plane. Unless you specify as such the model will simply assume outside air as the adjacent condition (this is even true of the ground!)

If you go into the constructions database and open the wall in question I think there is a check box for it.

CP

[p_sentobe]

Great thanks CP.

[PCully]

you're right, the VE doesn't assume this. Z=O is a nominal "ground level" for the Model Viewer to draw a ground plane but doesn't have any meaning beyond that really.

Options to define a surface as below ground level for purposes (should be covered elsewhere on this forum) are to add an adjacent condition to represent a theoretical ground temperature or adjust ground contact constructions to include for the effects of the ground, you can do this manually or usingt he Ground-Contact function in VE.

Phil

[RossThompson87]

Hi you also need to keep an eye on the notional building.

To my mind it shouldn't put glazing on a ground contact wall.

'Blocking' the wall with topographical shade should prevent this.

It may significantly help your results if the notional building has lots of daylight dimming etc. It could work the other way too as less glazing generally means less heat loss.