[Bldg-sim] Glas Curtain Wall - Appendix G

[Michael Tillou]

Matthew
 
Please remember that ASHRAE 90.1 defines fenestration area as the rough
opening for any window assembly including glazing , frame and sash, see the
definitions in Section 3 of the standard.  The minimum performance
requirements for fenestration include the performance of the frames.  The
frame area should be accounted for in your calculation of fenestration area
and performance.
 
Michael
 
 
Michael Tillou, PE, LEED
P: 413-458-9870 C: 413-652-1087
  
 
 

  _____  

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Leonard Sciarra
Sent: Thursday, February 14, 2008 7:07 PM
To: Michael Rosenberg; Higgins, Matthew
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Glas Curtain Wall - Appendix G


Matthew, 
If the clear glass, vision glass, daylight glass or whatever is greater than
40% reduce it proportionally to 40% and use the prescriptive 90.1 chapter 5
values.  For the remainder of the building (opaque portions) you then use
(for U-factor) the 'steel framed' wall values.
                                                    
Leonard Sciarra, AIA, LEEDR ap
Associate
312.577.6580  Direct
312.456.0123  Main
 <mailto:leonard_sciarra at gensler.com> leonard_sciarra at gensler.com
                                                     
Gensler
30 West Monroe
Suite 400
Chicago, Illinois 60603
USA 
 

  _____  

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Michael
Rosenberg
Sent: Thursday, February 14, 2008 1:33 PM
To: Higgins, Matthew
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Glas Curtain Wall - Appendix G


Matthew,
 
I think what you need to do is pull the opaque portion of the curtain wall
out. If the remaining glazing fraction is above 40%, than that portion needs
to be reduced in you baseline model. 
 
Mike
 
Michael Rosenberg
Oregon Department of Energy
625 Marion St. N.E.
Salem, OR 97301-3742
Phone : (503) 373-7809
Fax: (503) 373-7806

>>> Matthew Higgins <higgins at edi-arch.com> 2/14/2008 10:29:05 AM >>>

Michael - I assume you saw my previous post? (Below).... What I am wondering
is how LEED/ASHRAE 90.1-2004 Appendix-G treats glass curtain walls in
baseline models: either as a curtain wall with 90.1 climate-specific glass
properties or if I need to reduce the amount of glazing to 40% (the
prescriptive maximum Window/Wall ratio).

Your thoughts?

*PREVIOUS POST*

Has anyone modeled, submitted, and certified a LEED building with a 
glass curtain wall?

I ask because I am wondering how to treat the curtain wall in the 
baseline model. I've tried two scenarios thus far and there is a 10% 
consumption difference between them. The only thing that differs between 
the two is that the lower consuming model has a 40% window-to-wall area 
where the other is still a glass curtain wall, but using Appendix G 
window properties. And to put this in perspective the curtain wall is 
facing NNE and is 3 stories high.

I would also truly appreciate any reference to a LEED CIR regarding this 
issue, if there is one.

Matthew Higgins, LEED AP
Technical Specialist
Environmental Dynamics, Inc.
Architecture and Sustainability Consulting Services
505.242.2851



Matthew Higgins wrote:

>Has anyone modeled, submitted, and certified a LEED building with a 
>glass curtain wall?
>
>I ask because I am wondering how to treat the curtain wall in the 
>baseline model. I've tried two scenarios thus far and there is a 10% 
>consumption difference between them. The only thing that differs between 
>the two is that the lower consuming model has a 40% window-to-wall area 
>where the other is still a glass curtain wall, but using Appendix G 
>window properties. And to put this in perspective the curtain wall is 
>facing NNE and is 3 stories high.
>
>I would also truly appreciate any reference to a LEED CIR regarding this 
>issue, if there is one.
>
>  
>

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