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<div class=Section1>
<p class=MsoNormal><span style='color:#1F497D'>Hi Katherine,<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'>Your quote looks incomplete –
be sure you’re reading the whole section to avoid unnecessary confusion
;)<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo3'><![if !supportLists]><span
style='color:#1F497D'><span style='mso-list:Ignore'>1)<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='color:#1F497D'>Baseline fans are
auto-sized. Return fans (when required) must be specified with a CFM
capacity equal to either 0.90 x (the auto-sized CFM of the SA fan), or (the
auto-sized CFM of the SA fan) minus the OA for the same system, whichever is
greater. This is relatively simple if you let excel do the legwork.<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo3'><![if !supportLists]><span
style='color:#1F497D'><span style='mso-list:Ignore'>2)<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='color:#1F497D'>No. Whether
you model return fans in addition to your SA fans in your baseline model
systems is stipulated, not a choice. Re-read that section.<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo3'><![if !supportLists]><span
style='color:#1F497D'><span style='mso-list:Ignore'>3)<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='color:#1F497D'>No and Yes. “90%
of SA” = 0.90xSA = SA - (0.10xSA)<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo3'><![if !supportLists]><span
style='color:#1F497D'><span style='mso-list:Ignore'>4)<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='color:#1F497D'>Baseline RA fan
power is calculated following the same equations as SA fans. See
following section G3.1.2.9.<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>
<div>
<p class=MsoNormal><span style='color:#1F497D'><img width=119 height=37
id="Picture_x0020_1" src="cid:image001.jpg@01CB8577.63862810"
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;
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<p class=MsoNormal><span style='font-size:10.0pt;color:#2D4D5E'>fax 913
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<p class=MsoNormal><i><span style='font-size:10.0pt;color:#2D4D5E'>Check out
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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"'>
equest-users-bounces@lists.onebuilding.org
[mailto:equest-users-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Katherine
Roberts<br>
<b>Sent:</b> Tuesday, November 16, 2010 10:04 AM<br>
<b>To:</b> equest-users@lists.onebuilding.org<br>
<b>Subject:</b> Ashrae 90.1 query: Design air flow rates - return fans<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span lang=EN-GB>Dear all,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-GB>We are submitting a LEED project and have a
query regarding ASHRAE 90.1 (2004) section <b>G.3.1.2.8 – Design Air flow
rates. </b>It states that the baseline building should be modelled with fans
serving the ‘same functions and sized for the baseline system supply fan
air quantity less the minimum outdoor air, or 90% of the supply fan air
quantity, whichever is larger.’<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-GB>We figure there are 3 different ways to
interpret this sentence:<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span
lang=EN-GB><span style='mso-list:Ignore'>1)<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-GB>Model the baseline building with
supply fans as normal, plus return fans with either 90% supply or supply minus
outside air.<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span
lang=EN-GB><span style='mso-list:Ignore'>2)<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-GB>Only model supply fans but
change the supply flow rate to 90% or supply minus outside air.<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span
lang=EN-GB><span style='mso-list:Ignore'>3)<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-GB>Does 90% mean supply minus 90%
or supply minus 10%? <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-GB>If someone could provide an example that
would be very useful.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-GB>How do we incorporate the return fan power
when reporting total fan power allowances, i.e. do we subtract return fans from
the total?<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-GB>Thanks in advance<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-GB>Kat<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p>
<p class=MsoNormal><b><span style='font-family:"Times New Roman","serif";
color:#28AAE1'>Katherine Roberts<o:p></o:p></span></b></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Times New Roman","serif";
color:#595959'>Engineer | Enviromental Physics<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Times New Roman","serif";
color:#595959'><o:p> </o:p></span></p>
<p class=MsoNormal><b><span style='font-family:"Times New Roman","serif";
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<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Times New Roman","serif";
color:#595959'>13 Fitzroy Street London W1T 4BQ United Kingdom<o:p></o:p></span></p>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Times New Roman","serif";
color:#595959'>t</span></b><span style='font-size:10.0pt;font-family:"Times New Roman","serif";
color:#595959'> +44 20 7636 1531 <b>d</b> +44 20 7755 5454 <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Times New Roman","serif";
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<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Times New Roman","serif";
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<p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p>
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