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<p class=MsoNormal>I have a general question about how to model and prove
compliance for a window in an interior wall that separates conditioned space from
unconditioned space.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>We have a project where there is a conditioned area in the
parking level with a full height storefront window system separating the room from
the unconditioned garage.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>As far as I know, this “wall” is actually an
interior wall per ASHRAE 90.1-2004. Or rather, it’s not defined as
an exterior wall (at least clearly enough). For certain modeling and
compliance programs, you can’t even assign a window to an interior wall.
To further complicate things, the entire wall is window, meaning there is no
actual cavity space for insulation (which proves difficult for things like
Comcheck compliance).<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Does anyone know how ASHRAE 90.1 views this “wall”.
Is it really an exterior walls? Are ALL walls that separate conditioned
from unconditioned space considered exterior walls? If so, this is not
properly defined in ASHRAE. And if not, there doesn’t appear to be
anywhere that governs U-values for windows in INTERIOR walls that <u>separate conditioned
from unconditioned area</u>. In fact, from what I can tell, ASHRAE
advises you to IGNORE windows in interior walls. Which is all fine,
unless your entire wall is window. But at the same time, interior walls
appear to require a maximum U-value of 0.120. For a window, this is
nearly impossible.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Can anyone interpret 90.1 for me? Am I really allowed
to ignore windows in interior walls even if they separate conditioned space
from unconditioned space? <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Thanks in advance!<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><b><span style='font-size:12.0pt;font-family:"Arial","sans-serif";
color:teal'>GHT Limited<br>
</span></b><b><span style='font-family:"Arial","sans-serif"'><ns0:PersonName><span
style='color:black'>James Hansen</span></ns0:PersonName></span></b><b><span
style='font-size:12.0pt;font-family:"Times New Roman","serif";color:black'>,
PE, LEED AP<o:p></o:p></span></b></p>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
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