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<DIV><FONT size=2 face=Arial>Hi Wes,</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV>I agree, but for lack of someone else's better (or
any) standards, I'll use my standards. Point dead-loading at fasteners is a
design consideration as is fastener wind-loading. A well designed PV array will
disperse dead load points when wind loading is practically dealt with. I'm
all for standardized designs instead of having to get each rack reviewed and
possibly burdened with a structural engineering fee. I have done boilerplate
rack designs as have other designers, but that does not help you in your
jurisdiction. I think UniRac has done a good job of blazing the way toward
standardized rack designs. Perhaps wrenches can spring-board off their work to
establish a standard.</DIV>
<DIV> </DIV>
<DIV>For a while, one jurisdiction in Southern California did not require
structural engineering calculations for roof-mounted commercial PV arrays that
weighed less than 6 lb/ft2 on flat roofs less than 75 feet above grade.
Then they changed it to 4 lb/ft2. Now it is up to the Planning whether a
structural engineering stamp is required. The fundamental problems are (1) no
uniform nationwide requirement and (2) arbitrary and continuous AHJ requirement
changes. We can have a national standard and local AHJs can have specific
requirements, but please please please let's get them to stop changing the
rules for a couple of years so we can spend time on refining
designs that we now have.</DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Joel Davidson</FONT></DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=hathasolar@yahoo.com href="mailto:hathasolar@yahoo.com">wes
kennedy</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=re-wrenches@lists.re-wrenches.org
href="mailto:re-wrenches@lists.re-wrenches.org">RE-wrenches</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, July 10, 2009 10:44
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [RE-wrenches] Roof Loading
request for help</DIV>
<DIV><BR></DIV>
<TABLE border=0 cellSpacing=0 cellPadding=0>
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<TR>
<TD vAlign=top>Hi All,<BR><BR>I am fully in favor of standardized
permitting, and streamlining the process of installing PV. With
that said, I do think the "one layer of shingles = PV on roof thing" is
apples and oranges. Though the deadloading in psf is similar, PV
doesn't sit on the roof, it lands on some sort of attachment, standoff,
l-foot, what-have-you.<BR><BR>This leads to pretty high point loading
values, doesn't it? If you spread your 1000 lb array around 300
square feet, you get your 3.3 psf, BUT if it lands on 30 L feet, each of
4 square inches you end up with much higher points of concentrated
loading.<BR><BR>Anybody worry about that? <BR><BR>Thanks!<BR>Wes
Kennedy<BR>NABCEPian<BR> <BR><BR>--- On <B>Tue, 7/7/09, Joel
Davidson <I><joel.davidson@sbcglobal.net></I></B> wrote:<BR>
<BLOCKQUOTE
style="BORDER-LEFT: rgb(16,16,255) 2px solid; PADDING-LEFT: 5px; MARGIN-LEFT: 5px"><BR>From:
Joel Davidson <joel.davidson@sbcglobal.net><BR>Subject: Re:
[RE-wrenches] Roof Loading request for help<BR>To: "RE-wrenches"
<re-wrenches@lists.re-wrenches.org><BR>Date: Tuesday, July 7,
2009, 7:13 PM<BR><BR>
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<DIV><FONT size=2 face=Arial>Allan,</FONT></DIV>
<DIV><FONT size=2 face=Arial>In most of California (seismic zone 4)
residential PV systems with solar arrays weighing less than 4 lb/ft2
do not require structural engineering if the roof has one layer of
composition shingles. The reasoning is that roofs are allowed 2 layers
of shingles (old set and re-roof set) and a layer of shingles
weighs 4 lb/ft2 so 1 shingle layer and 1 solar array weighing less
than 4 lb/ft2 is within the dead weight load limit. Hope this
helps.</FONT></DIV>
<DIV><FONT size=2 face=Arial>Joel Davidson</FONT></DIV>
<BLOCKQUOTE
style="BORDER-LEFT: rgb(0,0,0) 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV
style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal; -x-system-font: none">-----
Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: rgb(228,228,228); font-size-adjust: none; font-stretch: normal; -x-system-font: none; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial"><B>From:</B>
<A title=allan@positiveenergysolar.com
href="/mc/compose?to=allan@positiveenergysolar.com" rel=nofollow
target=_blank ymailto="mailto:allan@positiveenergysolar.com">Allan
Sindelar</A> </DIV>
<DIV
style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal; -x-system-font: none"><B>To:</B>
<A title=re-wrenches@lists.re-wrenches.org
href="/mc/compose?to=re-wrenches@lists.re-wrenches.org" rel=nofollow
target=_blank
ymailto="mailto:re-wrenches@lists.re-wrenches.org">'RE-wrenches'</A>
</DIV>
<DIV
style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal; -x-system-font: none"><B>Sent:</B>
Tuesday, July 07, 2009 5:26 PM</DIV>
<DIV
style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal; -x-system-font: none"><B>Subject:</B>
[RE-wrenches] Roof Loading request for help</DIV>
<DIV><BR></DIV>
<DIV class=Section1>
<P class=MsoNormal><FONT size=2 face=Arial><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt">Wrenches,</SPAN></FONT></P>
<P class=MsoNormal><FONT size=2 face=Arial><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt">We are currently facing
a city permitting bureaucracy that has recently discovered solar –
that is, suddenly each department in the permitting and plan review
departments is coming up with standards for PV systems. Some of the
standards, of course, make no sense. </SPAN></FONT></P>
<P class=MsoNormal><FONT size=2 face=Arial><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt"></SPAN></FONT> </P>
<P class=MsoNormal><FONT size=2 face=Arial><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt">PV systems typically add
about three pounds per square foot to the loading on a roof. We are
facing a city requirement for structural
engineering work for standard roof attachment if the
mounting approach is to make penetrations into the roof structure.
This is a typical requirement that will only add considerable cost
to each PV system, and we’re looking to have our ammunition to fight
this well stocked in advance. Specifically, are building authorities
in other jurisdictions requiring structural
engineering work for this type of roof
attachment?</SPAN></FONT></P>
<P class=MsoNormal><FONT size=2 face=Arial><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt"></SPAN></FONT> </P>
<P class=MsoNormal><FONT size=2 face=Arial><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt">Thanks
</SPAN></FONT></P>
<P class=MsoNormal><FONT size=2 face=Arial><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt">Allan</SPAN></FONT></P>
<P class=MsoNormal><FONT size=2 face=Arial><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt"></SPAN></FONT> </P>
<P class=MsoNormal><FONT size=3 face="Times New Roman"><SPAN
style="FONT-SIZE: 12pt">Allan Sindelar</SPAN></FONT></P>
<P class=MsoNormal><FONT size=2 face="Times New Roman"><SPAN
style="FONT-SIZE: 10pt"><A
href="/mc/compose?to=Allan@positiveenergysolar.com" rel=nofollow
target=_blank
ymailto="mailto:Allan@positiveenergysolar.com">Allan@positiveenergysolar.com</A></SPAN></FONT></P>
<P class=MsoNormal><FONT size=2 face="Times New Roman"><SPAN
style="FONT-SIZE: 10pt">NABCEP Certified Photovoltaic
Installer</SPAN></FONT></P>
<P class=MsoNormal><FONT size=2 face="Times New Roman"><SPAN
style="FONT-SIZE: 10pt">EE98J Journeyman
Electrician</SPAN></FONT></P>
<P class=MsoNormal><FONT size=3 face="Times New Roman"><SPAN
style="FONT-SIZE: 12pt">Positive Energy, Inc.</SPAN></FONT></P>
<P class=MsoNormal><FONT size=3 face="Times New Roman"><SPAN
style="FONT-SIZE: 12pt">3201 Calle Marie</SPAN></FONT></P>
<P class=MsoNormal><FONT size=3 face="Times New Roman"><SPAN
style="FONT-SIZE: 12pt">Santa Fe</SPAN></FONT> , New Mexico
87507</P>
<P class=MsoNormal><FONT size=3 face="Times New Roman"><SPAN
style="FONT-SIZE: 12pt">505 424-1112</SPAN></FONT></P>
<P class=MsoNormal><FONT size=2 face=Arial><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt"><A
href="http://www.positiveenergysolar.com" rel=nofollow
target=_blank>www.positiveenergysolar.com</A></SPAN></FONT></P>
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style="FONT-SIZE: 12pt"></SPAN></FONT> </P></DIV>
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