This May 2010 UL/NFPA report "Fire Fighter Safety and Emergency Response for
Solar Power Systems" shows eave-to-ridge solar arrays and has a lot of good
information for designers. See
http://www.nfpa.org/assets/files/PDF/Research/FFTacticsSolarPower.pdf
----- Original Message -----
From: Mick Abraham
To: RE-wrenches
Sent: Thursday, August 26, 2010 5:53 PM
Subject: Re: [RE-wrenches] Tight roof layout questions: edge walkway
requirements & "small gap" hardware options
The Wrench List participants have again responded with aplomb. Thanks to all
for the dozen or so replies. My takeaway from this is that I need to send my
roof layouts to the nearby fire department...it's another "authority having
jurisdiction" situation.
I received the below mail "off list" from a fire captain in San Jose. He
cannot post to the List so he asked me to post on his behalf. Moderator Michael
approved, so Matt Paiss' remarks are copied below.
Jolliness,
Mick Abraham, Proprietor
www.abrahamsolar.com
Voice: 970-731-4675
Mick,
I wanted to reply to your post. As a firefighter, and an instructor of PV
safety for the fire service like Dan Fink, I would like to take a moment to
expand on what Dan was eluding to. Firefighters will not always look at an
edge-to-edge array and decide to "Let it burn" just based on the array size.
We will take into account the size of the fire, the involvement of the actual
structural members, and the potential life risk within the structure before any
tactical strategy is implemented. I have written off buildings just based on
wind, or available water supply.
What a setback (the term being used for walkways) allows is primarily for
access to a roof, or rapid egress off a roof when the fire gets out of control,
not necessarily for cutting a hole. I teach firefighters to vent on the other
side of the ridge from the array. There is no time to remove modules, and
while micro-inverters definitely address the safety issues of a 600vdc string,
they do not address access or egress. I am not going to recommend that ANY
firefighter tear off a module to vent a roof because he "thinks" a
micro-inverter is present.
I realize that these new codes are more restrictive, but even wind load
zones recommend against edge-to-edge installs. There will be some latitude in
the fire codes for setbacks, so I recommend building a good relationship with
your local AHJ's. One way of doing this is by demonstrating safe, high quality
installs. I have seen too many wire-ties holding up PV wire that will be
rubbing against comp shingles for a decade. How confident are you that that
will not be a problem?
Regards,
Matt Paiss
Matthew Paiss, Fire Captain
San Jose Fire Department
170 W. San Carlos St.
San Jose, CA 95113
(831) 566-3057 cell
On Thu, Aug 26, 2010 at 12:45 AM, Philip Boutelle <philboute...@gmail.com>
wrote:
Just to clarify what is and isn't law in California:
the final draft guidelines developed and adopted by Cal Fire are
guidelines, not law, unless the local fire/AHJ has adopted them or parts of
them into local ordinances. I have heard that in Southern Cal, those guidelines
have been adopted all over the place already, but not so in the rest of the
state.... yet. I think the guideline was officially incorporated into the next
NEC/NFPA cycle, so it will be law pretty soon. Bill Brooks could probably
confirm here on future adoption.
Not that any of this helps your Atlanta install....
-Phil Boutelle
Real Goods Solar
On Wed, Aug 25, 2010 at 12:38 PM, Max Balchowsky <m...@seesolar.com> wrote:
Mick, here in California the fire department in the various agencies has
the final say on clearances. There is a very clear cut standard in place for
the state, but we have been successful a few times in getting allowances to
vary due to various site conditions. A call to the local AHJ is the place to
start. In the early days of our installations (mid 1990's) we used power strut
and bolted panels directly to the rails. A lot slower but no gaps between
panels. We went from there to designing our own "T" clamps. There wasn't as
many choices then for mounting hardware.
Max Balchowsky
Design Engineer
SEE Systems
1048 Irvine Ave Suite 217
Newport Beach, Ca. 92660
760-403-6810
--------------------------------------------------------------------------
From: Brian Teitelbaum <bteitelb...@aeesolar.com>
To: RE-wrenches <re-wrenches@lists.re-wrenches.org>
Sent: Wed, August 25, 2010 11:40:04 AM
Subject: Re: [RE-wrenches] Tight roof layout questions: edge walkway
requirements & "small gap" hardware options
Hi Mick,
To answer part of your post, the DPW Power Rail mid-clamps give you a
3/8” gap between modules, and the SnapNrack mids give you a 1/2" gap.
I doubt if that will give you much of a walkway though….
Brian Teitelbaum
AEE Solar
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Mick Abraham
Sent: Wednesday, August 25, 2010 11:09 AM
To: RE-wrenches
Subject: [RE-wrenches] Tight roof layout questions: edge walkway
requirements & "small gap" hardware options
Hello, Team~
I'm laying out some Sanyo modules on paper. Twelve of them fit the roof
with almost too much perfection: this would be difficult to install as it would
fill the roof "edge to edge" in both directions. Are there consistent
guidelines about the amount of roof edge which must remain uncluttered or is
this mainly driven by the amount of aggravation that the installer is willing
to tolerate? Which organizations would want to influence such decisions in the
Atlanta region? Details are: residential, new construction, wooden truss type
roof framing, finish roofing yet to be decided.
I've seen fancy photos of rooftops which are covered edge to edge, but I
suppose those are "building integrated" PV systems instead of discrete modules
mounted above the roofing material. Who decides if those are "OK' for no
walkways compared to a roof that is fully loaded with Sanyo type modules? How
are such decisions made?
I like the "top clamp" style mounts but UniRac SolarMount rail systems
need about a 1" gap from one module to the next. Is there anyone with similar
hardware that can get a grip within a smaller gap?
Thanks in advance,
Mick Abraham, Proprietor
www.abrahamsolar.com
Voice: 970-731-4675
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