<div dir="ltr"><div class="gmail_default" style=""><p class="MsoNormal" style="margin-bottom:0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><br><font color="#274e13" face="Arial, sans-serif"><span style="font-size:10pt">
Dear all,</span></font><br><br><font color="#274e13" face="Arial, sans-serif"><span style="font-size:10pt">
I am modeling a historic building and the scope of work is to modify the existing windows
by adding a storm window to the existing industrial steel </span><span style="font-size:13.3333px">sash</span><span style="font-size:10pt"> windows. The
storm window is one layer Low-E glass with aluminum framing with </span><span style="font-size:13.3333px">brake</span><span style="font-size:10pt"> (assembly
U-0.67).</span></font><br><font color="#274e13" face="Arial, sans-serif"><span style="font-size:10pt">
Assuming the existing one layer clear glass window has U-value of 5.8, can I
assume the assembly R-value of the window system as the total R-values of both
of the windows as following, and would it be acceptable by the LEED reviewer?</span></font><br><br><font color="#274e13" face="Arial, sans-serif"><span style="font-size:10pt"></span></font></p>

<p class="MsoNormal" style="color:rgb(39,78,19);font-family:tahoma,sans-serif;margin-bottom:0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span style="font-size:10pt;font-family:Arial,sans-serif">Total R-Value: 1/5.8 +
1/0.67 = 0.172 + 1.49 = 1.662<br>
U-Value = 1/1.662 = 0.6<br><br><span></span></span></p>

<p class="MsoNormal" style="color:rgb(39,78,19);font-family:tahoma,sans-serif;margin-bottom:0.0001pt;line-height:normal;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><span style="font-size:10pt;font-family:Arial,sans-serif">I would appreciate
your help in this matter,<br>
Morteza<span></span></span></p></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(39,78,19)"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;color:rgb(39,78,19)"><br></div><div><div class="gmail_signature"><div dir="ltr"><img src="https://lh6.googleusercontent.com/Uuukta80GuFfvKouzA0mdSvUXqml7MtSwSiw-evuGMU=w147-h43-p-no"><br><div><br></div></div></div></div>
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