Ballasted panel mounting [RE-wrenches]

[John Berdner]

Wrenches:

Be a little bit careful with ballasted structures.
When I was at Endecon (PG&E) we did a ballasted structure as part of the
EPA PV project.
We found a problem with ballasted structures and the Uniform Building
Code.
The UBC has a section for seismic loading and it says you can't use
friction to resist seismic forces.
The basic idea is that during an earthquake the ballasted structure
bounces up into the air and it can "walk" off the roof as the building
moves around.

According to the UBC you have to attach it to the roof somehow.
As I recall a Zone 4 area (most of CA) requires you to resist a lateral
force of about 0.3 times the weight.
The city of San Ramon made us tie the system down with a cable leash
attached to the building structure.
Really ugly and expensive.

The good news is that UBC is not as widely adopted as the NEC and so you
might be ok.
But then again if the inspector requires you to meet the UBC requirement
it can be a big unplanned expense.

If you have any questions or I can be of any further assistance please
do not hesitate to contact me.

Best regards,

John Berdner

SMA-America, Inc.
20830 Red Dog Road
Grass Valley, CA  95945
Tel: 530.273.4895
Fax: 530.274.7271



-----Original Message-----
From: Joel Davidson [mailto:joeldavidson at earthlink.net]
Sent: Wednesday, January 02, 2002 4:28 PM
To: RE-wrenches at topica.com
Subject: Re: Ballasted panel mounting [RE-wrenches]


Bob,
The ConSole ballast pan
http://www.ibc-solar.de/english/html/Untermenues/produkte/kunststoffwann
en/CONSOLEE.PDF
will work on very strong flat roofs. Most "flat" roofs in SoCal are 1 in
12 pitch and not strong enough to support a lot of ballast. The 4 kg.
weight is just the tub so you have to factor in the gravel ballast in
the equation. Be prepared to spend time and money on structural
engineering to convince the building department that ConSole will work
here. Powerlight PV systems in Anaheim, L.A. and elsewhere in SoCal
weigh under 7 pounds per square foot and have steel cables tying the
perimeter ballasted pans together to make the array a monolithic block.
Best regards,
Joel Davidson

Bob Galbreath wrote:
>
> I've got a client whom we have done some remote site work for who is
now
> interested in an installation using some of our equipment for his
> business and home. He has done some research and is very interested in
> avoiding roof penetrations. He has suggested using ballast pans for
the
> PV panel mounting and is particularly interested a Dutch product
called
> Console.
>
> Both these installations would be on flat roofs in southern CA.  One
> roof is composition material, the other is membrane. Both roofs have
> parapet walls which might allow some lateral bracing.
>
> Anybody have experience with these systems?
>
> Is this going to fly with So Cal's seismic codes?
>
> Bob Galbreath
> Geo-Lite Systems
> www.geolitesystems.com
>
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