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<DIV dir=ltr align=left><SPAN class=598085323-14022008>Matthew, </SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=598085323-14022008>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.</SPAN></DIV>
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<FONT face=Tahoma><B>From:</B> bldg-sim-bounces@lists.onebuilding.org
[mailto:bldg-sim-bounces@lists.onebuilding.org] <B>On Behalf Of </B>Michael
Rosenberg<BR><B>Sent:</B> Thursday, February 14, 2008 1:33 PM<BR><B>To:</B>
Higgins, Matthew<BR><B>Cc:</B> bldg-sim@lists.onebuilding.org<BR><B>Subject:</B>
Re: [Bldg-sim] Glas Curtain Wall - Appendix G<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV>Matthew,</DIV>
<DIV> </DIV>
<DIV>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. </DIV>
<DIV> </DIV>
<DIV>Mike</DIV>
<DIV> </DIV>
<DIV>Michael Rosenberg<BR>Oregon Department of Energy<BR>625 Marion St.
N.E.<BR>Salem, OR 97301-3742<BR>Phone : (503) 373-7809<BR>Fax: (503)
373-7806<BR><BR>>>> Matthew Higgins <higgins@edi-arch.com>
2/14/2008 10:29:05 AM >>><BR></DIV>
<DIV style="COLOR: #000000">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).<BR><BR>Your
thoughts?<BR><BR>*PREVIOUS POST*<BR><BR>Has anyone modeled, submitted, and
certified a LEED building with a <BR>glass curtain wall?<BR><BR>I ask because I
am wondering how to treat the curtain wall in the <BR>baseline model. I've tried
two scenarios thus far and there is a 10% <BR>consumption difference between
them. The only thing that differs between <BR>the two is that the lower
consuming model has a 40% window-to-wall area <BR>where the other is still a
glass curtain wall, but using Appendix G <BR>window properties. And to put this
in perspective the curtain wall is <BR>facing NNE and is 3 stories
high.<BR><BR>I would also truly appreciate any reference to a LEED CIR regarding
this <BR>issue, if there is one.<BR><BR>Matthew Higgins, LEED AP<BR>Technical
Specialist<BR>Environmental Dynamics, Inc.<BR>Architecture and Sustainability
Consulting Services<BR>505.242.2851<BR><BR><BR><BR>Matthew Higgins
wrote:<BR><BR>>Has anyone modeled, submitted, and certified a LEED building
with a <BR>>glass curtain wall?<BR>><BR>>I ask because I am wondering
how to treat the curtain wall in the <BR>>baseline model. I've tried two
scenarios thus far and there is a 10% <BR>>consumption difference between
them. The only thing that differs between <BR>>the two is that the lower
consuming model has a 40% window-to-wall area <BR>>where the other is still a
glass curtain wall, but using Appendix G <BR>>window properties. And to put
this in perspective the curtain wall is <BR>>facing NNE and is 3 stories
high.<BR>><BR>>I would also truly appreciate any reference to a LEED CIR
regarding this <BR>>issue, if there is one.<BR>><BR>>
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