[RE-wrenches] Tight roof layout questions: edge walkway requirements & "small gap" hardware options

Nick Soleil nicksoleilsolar at yahoo.com
Thu Aug 26 23:24:47 PDT 2010 

Almost all city jurisdictions in the North Bay Area are currently requiring the 
fire access walkways.  So we have definitely had to scale back a few of our 
system sizes to accommodate the walkways, and one project even cancelled when 
they realized they couldn't fit the system size that they wanted.  One of the 
more difficult jurisdictions, Napa City, requires walkways on both sides of the 
roof and along the top.  

    Also, to clarify a statement that made earlier, regarding the gap with 
Prosolar's TileTrac system, the mid clip is 5/8" wide.  This is 3/8" thinner 
than the Unirac mid-clip, which is 1".  This results in a 3" savings across an 8 
module array.

 Nick Soleil
Project Manager
Advanced Alternative Energy Solutions, LLC
PO Box 657
Petaluma, CA 94953
Cell:   707-321-2937
Office: 707-789-9537
Fax:    707-769-9037




________________________________
From: Mick Abraham <mick at abrahamsolar.com>
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Sent: Thu, August 26, 2010 5:53:31 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 CaptainSan 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 <philboutelle at 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 <max at 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 <bteitelbaum at aeesolar.com>
>>To: RE-wrenches  <re-wrenches at 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-bounces at lists.re-wrenches.org 
>>[mailto:re-wrenches-bounces at 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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