Curtain Wall

[DS40]

Hi,

I am trying to create a curtain wall construction in Building Template Manager but after entering the other materials it does not let me add glass as a layer in an external wall.

The wall construction is glass/airgap/glass/cavity/insulation/ plywood/ insulation/ cavity/ plasterboard.

Any help would be appreciated. Thanks

[KasperS]

Hello

You cannot do that i IES VE. The only thing i can think of is if you add another room to the surface, which have the window to the outside and then the other construction to the inside.

Kasper

[ZapBran]

From the IES knowledge Base:

How do I model Curtain Walling?
Model the curtain walling like you would model windows.Using the Apache Constructions Database create a construction for the curtain walling material then assign it to the glazed surface in Apache. To assign this construction to only one surface go down the levels of decomposition, using the blue arrow at the bottom of the screen.

Our understanding of the Part L2 regulations with regards to curtain walling, following discussions with some building control officers, is that transparent sections of curtain walling should have an average U-value of no greater than 2.2W/m2K and a limiting U-value of 3.3W/m2K. The opaque section of curtain walling should be treated the same as wall fabric so that the building has an overall external wall U-value of 0.35W/m2K and a limiting U-value of 0.7W/m2K.

In other projects we are aware that an additionally insulated section of wall is being installed behind the opaque sections in order to provide the required U-value.I suggest you contact building control to discuss the limiting U-Values applicable.

Not used the knowledge base before?
You can search the knowledge base by going here: http://www.iesve.com/support/search.

Zap messing about
Would another idea be to model a glass wall zone? I'm only putting it out there to get shot down but how about this:



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[DS40]

Thanks for the reponses Kasper and Zap. I will give them a try to determine which method gives the best results.

It is odd IES doesn't allow you to create a fabric construction using my combination of materials since they are all in the database?

Having to manually calculate a U value, Admittance, decrement factor etc of this fabric combination when the materials are hardly out of the ordinary is not good for a software package that does so many other intricate things so well.Perhaps this will be addressed in the next update.

[KasperS]

IESVE doesnt allow you to put glas on the floor either... there are many restrictions in the code, which most likely origins from the difficulties with the programming.

[luanaepb]

Hi!

Currently, I'm using the 2012 version of IES-VE and one of the options, when I define opaque constructions, is to tick "Curtain walls". I've tried to find how to use this in the most recent guide but I didn't find.

Does anyone knows how to use it or what changes when you tick that?

Thanks!

[DS40]

Hi luanaepb,

Yes I couldnt find anything in the latest user guide for curtain walling so I would be interested in the responses you get about this too.

I did solve my issue in a very simple way that the professors did not suggest and it appears to work ok. You CAN add glass as a layer to an opaque fabric. This is done using plate glass found in 'Boards, Sheets and Decking' rather than glass fabrics. If plate glass is not present in the standard choices under 'Boards, Sheets and Decking' you may need to import one of the preloaded construction templates.

Hope this is of use

[luanaepb]

Hi DS40, =)

I've tried this option in "'Boards, Sheets and Decking" and it works!

But what I don't see is how the glass propreties are translated to the construction, I mean, transmittance, reflectance, etc.

Do you have any idea?

Thanks for your answer!

[DS40]

Hi luanaepb,

Fabric information required for thermal calculation are included in the properties for plate glass ie thickness, SHC, conductivity etc.

Transmittance and reflectance are only relevant when looking at light transmittance through glazing. Curtain walling is opaque so no light passes through it.

Not sure if that answers your query?
If you have a curtain wall that also contains glass panes then create the curtain wall and apply it as external wall and then add windows/glazing in the usual way. If the problem is that you have more than one external wall type on the same wall this can be overcome by creating an external door fabric with the properties that you need for the smaller area of external wall. Apply this as a 'door' (It can be any rectangular shape/ size so does not have to be a standard door size) rather than an external wall.

Hope this helps. Post again if not and I will try and help you if I can. I know how frustrating some of these modelling issues can be!

[PCully]

hi,

Just to add a clarification to this as you seem to have made good progress yourselves.

The Curtain Wall option in CDB I believe is only relevant to Compliance regulations, certainly for Part L2 you would have to tick this so the surfaces were assessed in the correct category for the U-value checks. I don't think it does anything thermally (I could be wrong on that but the tests you have run yourself seem to back this up).

Phil