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<p class=MsoNormal><span style='color:#1F497D'>Janne et al,<o:p></o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'>Since IECC 2009 section 501.1 continues
the happy tradition of permitting one to dismiss IECC entirely and instead defer
to 90.1-2007 for commercial buildings, here’s my interpretation under
90.1-2007 (all the figures should match regardless for this exercise)…<o:p></o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'>The prescriptive envelope option
of 90.1-2007 has the same following 3 independent requirements for a steel
framed wall in climate zone 5:<o:p></o:p></span></p>

<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span
style='color:#1F497D'><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'>         
</span></span></span><![endif]><span style='color:#1F497D'>R-13 batt <o:p></o:p></span></p>

<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span
style='color:#1F497D'><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'>         
</span></span></span><![endif]><span style='color:#1F497D'>R-7.5 c.i.<o:p></o:p></span></p>

<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span
style='color:#1F497D'><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'>         
</span></span></span><![endif]><span style='color:#1F497D'>Assembly Maximum U-0.064<o:p></o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'>The wall you’re describing
does not meet the prescriptive requirements for a ‘steel framed’
assembly on two fronts:  The U-value exceeds the maximum (not minimum!) of
0.064, and from what your description there’s also no batt insulation... 
<o:p></o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'>Combining the first two steel
framed requirements into an “effective c.i.” figure is an
interpretation of compliance I haven’t encountered… But it would
appear even by that metric that the proposed assembly falls short from your
description.<o:p></o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'>ON THE OTHER HAND, the envelope appears
to fall neatly within the requirements for a ‘mass’ wall (no batt
requirement, min c.i. 11.4, max U-0.09).  A very important nuance (re:  the
90.1 glossary and/or IECC 502.2.3) is that walls with steel framing can still
be ‘mass’ walls.  I did the math once under 90.1’s
definitions, and came away with a rule of thumb that <u>any</u> assembly including
a 4” brick/masonry layer = a ‘mass’ wall as far as these prescriptive
tables are concerned.  <o:p></o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'>Also to confirm Larry’s hunch
- The maximum assembly U-values correspond closely to the assembly R-value you’d
calculate if you added up all the base assembly layers as detailed in 90.1
Appendix A section A3 (re: archived discussion in the [equest-users] list if
interested).<o:p></o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'>~Nick<o:p></o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'>PS: Anyone in the position of
designing around or enforcing IECC should be keenly aware of that deferral to
90.1, and should probably have the corresponding referenced version handy as a
reference.  I think you’ll find 90.1 is much more clearly organized
and worded for those moments when IECC causes raised eyebrows =).  <o:p></o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>

<div>

<p class=MsoNormal><span style='color:#1F497D'><img width=119 height=37
id="Picture_x0020_1" src="cid:image001.jpg@01CB9C78.DDE78FA0"
alt="cid:489575314@22072009-0ABB"></span><b><span style='font-family:"Stylus BT","sans-serif";
color:#2D4D5E'><o:p></o:p></span></b></p>

<p class=MsoNormal><b><span style='font-family:"Stylus BT","sans-serif";
color:#2D4D5E'><o:p> </o:p></span></b></p>

<p class=MsoNormal><b><span style='font-family:"Stylus BT","sans-serif";
color:#2D4D5E'>NICK CATON, E.I.T.</span></b><b><span style='font-size:12.0pt;
font-family:"Stylus BT","sans-serif";color:#2D4D5E'><o:p></o:p></span></b></p>

<p class=MsoNormal><span style='font-size:7.5pt;color:#CC9900'>PROJECT ENGINEER<o:p></o:p></span></p>

<p class=MsoNormal><span style='font-size:10.0pt;color:#2D4D5E'>Smith &
Boucher Engineers</span><span style='font-size:7.5pt;font-family:"Times New Roman","serif";
color:#CC9900'><o:p></o:p></span></p>

<p class=MsoNormal><span style='font-size:10.0pt;color:#2D4D5E'>25501 west
valley parkway<o:p></o:p></span></p>

<p class=MsoNormal><span style='font-size:10.0pt;color:#2D4D5E'>olathe ks 66061<o:p></o:p></span></p>

<p class=MsoNormal><span style='font-size:10.0pt;color:#2D4D5E'>direct 913
344.0036<o:p></o:p></span></p>

<p class=MsoNormal><span style='font-size:10.0pt;color:#2D4D5E'>fax 913
345.0617<o:p></o:p></span></p>

<p class=MsoNormal><span style='color:#1F497D'><a href="www.smithboucher.com"
title="blocked::www.smithboucher.com"><span style='font-size:10.0pt'>www.smithboucher.com</span></a></span><u><span
style='font-size:10.0pt;color:blue'> </span></u><span style='color:#1F497D'><o:p></o:p></span></p>

</div>

<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>

<div>

<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>

<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
bldg-sim-bounces@lists.onebuilding.org [mailto:bldg-sim-bounces@lists.onebuilding.org]
<b>On Behalf Of </b>Larry Degelman<br>
<b>Sent:</b> Wednesday, December 15, 2010 4:00 PM<br>
<b>To:</b> Janne Kairento; bldg-sim@lists.onebuilding.org<br>
<b>Subject:</b> Re: [Bldg-sim] Mass. Energy Code<o:p></o:p></span></p>

</div>

</div>

<p class=MsoNormal><o:p> </o:p></p>

<div>

<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Janne,</span><span
style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p>

</div>

<div>

<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></p>

</div>

<div>

<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>R-values
in the energy code tables are just for insulation materials.  The intent
of the code when limiting U-factors is that you include all layers of the
entire assembly, and not just the insulating materials.  This is why the
U-value requirement is very seldom equal to 1/R.  What you should do is
add all R-values for the insulation, skin materials on the wall, and the
indoor and outdoor air film coefficients.  Then compute the U-value and
see if it meets the 0.064 limit.</span><span style='font-size:12.0pt;
font-family:"Times New Roman","serif"'><o:p></o:p></span></p>

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<div>

<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></p>

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<div>

<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>I
believe that most of the values presented in the tables have already assumed
certain bridging conditions, and that is why (repeating what I said above)
the R-values for insulation materials do not usually match the inverse of the
overall U-factors.  You can see this more clearly when you look at below
grade walls.  Since no air film would be present, the insulation
requirement is expressed as C.  The value C-0.119 inverted is R-8.4,
whereas the R-value requirement is just R-7.5.  In this case, the
remaining 0.9 R-value is assumed to be available from the masonry wall. </span><span
style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p>

</div>

<div>

<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></p>

</div>

<div>

<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Regards,</span><span
style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p>

</div>

<div>

<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></p>

</div>

<div>

<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>LOD  </span><span
style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></p>

</div>

<div>

<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>===========================<br>
Larry O. Degelman, P.E.<br>
Professor Emeritus of Architecture<br>
Texas A&M University<br>
<a href="mailto:ldegelman@suddenlink.net"
title="mailto:ldegelman@suddenlink.net CTRL + Click to follow link">ldegelman@suddenlink.net</a><br>
===========================</span><span style='font-size:12.0pt;font-family:
"Times New Roman","serif"'><o:p></o:p></span></p>

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<div>

<div>

<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><o:p> </o:p></span></p>

</div>

<div>

<div>

<p class=MsoNormal style='background:whitesmoke'><b><span style='font-size:
10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> <a
href="mailto:JKairento@B2Qassociates.com"
title="mailto:JKairento@B2Qassociates.com CTRL + Click to follow link">Janne
Kairento</a> <o:p></o:p></span></p>

</div>

<div>

<p class=MsoNormal style='background:whitesmoke'><b><span style='font-size:
10.0pt;font-family:"Tahoma","sans-serif"'>Sent:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Wednesday, December
15, 2010 2:16 PM<o:p></o:p></span></p>

</div>

<div>

<p class=MsoNormal style='background:whitesmoke'><b><span style='font-size:
10.0pt;font-family:"Tahoma","sans-serif"'>To:</span></b><span style='font-size:
10.0pt;font-family:"Tahoma","sans-serif"'> <a
href="mailto:bldg-sim@lists.onebuilding.org"
title="bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a> <o:p></o:p></span></p>

</div>

<div>

<p class=MsoNormal style='background:whitesmoke'><b><span style='font-size:
10.0pt;font-family:"Tahoma","sans-serif"'>Subject:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> [Bldg-sim] Mass.
Energy Code<o:p></o:p></span></p>

</div>

</div>

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<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></p>

</div>

<p class=MsoNormal>Hello!<o:p></o:p></p>

<p class=MsoNormal><o:p> </o:p></p>

<p class=MsoNormal>For Climate Zone 5, IECC requires a minimum insulation value
of R-13 + R-7.5 c.i. for a steel framed building. If the studs are 16” on
center, the thermal bridging degrades the batt R-value of 13 down to an
effective R-6 c.i. which bring the total insulation value to R-13.5 c.i. Currently,
I am reviewing a building with 2.5” of R-5 extruded polystyrene total an
insulation value of R-12.5 c.i. However, the building wall assembly exceeds the
‘Assembly Minimum’ of U-value 0.064. Since IECC 2009 is the
effective energy code of Massachusetts since June 30, 2010, is the insulation
assembly in agreement with the Minimum Envelope Requirements if the
‘Assembly Maximum’ is exceeded? Any input will be much appreciated!<o:p></o:p></p>

<p class=MsoNormal><o:p> </o:p></p>

<p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:black'>Regards,<o:p></o:p></span></p>

<p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:black'><o:p> </o:p></span></p>

<p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:black'>Janne
Kairento</span><o:p></o:p></p>

<p class=MsoNormal><o:p> </o:p></p>

<p class=MsoNormal><o:p> </o:p></p>

<div class=MsoNormal align=center style='text-align:center'><span
style='font-size:12.0pt;font-family:"Times New Roman","serif"'>

<hr size=2 width="100%" align=center>

</span></div>

<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'>_______________________________________________<br>
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To unsubscribe from this mailing list send  a blank message to
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