Oh, to have 85 mph winds. Code changes just brought us up to 180 mph design wind speeds in Southwest Florida. Yay.
Jason Szumlanski Fafco Solar On Mar 24, 2012, at 5:05 PM, Kent Osterberg <[email protected]> wrote: > William, > > There are auger mounted systems that don't require any concrete. For > locations with suitable soil, they probably save some time and are a little > less expensive than concrete. But it takes a substantial structure to > withstand 85 mph, or greater, winds. There's no getting around the physics of > that. > > Oregon also requires PV mounting structures to be engineered unless they meet > conditions prescribed in the solar installation code. The prescriptive rules > only apply to roof mounted systems, so ground mounts require a structural > engineer to sign off on the construction plans. > > Kent Osterberg > Blue Mountain Solar, Inc. > www.bluemountainsolar.com > > > On 3/24/2012 10:29 AM, William Miller wrote: >> Daryl: >> >> Thanks for the photos and description of the mounts you are installing. We >> have installed many of the DPW ground mount systems in similar >> configurations. >> http://millersolar.com/MillerSolar/Portfolio/ground-mount/engineered_ground_mount.jpg >> >> We are realizing two things: >> >> 1. Concrete footings of any type are expensive. The cost of excavation, >> forming and concrete really adds up. >> >> 2. For off-grid, when the module tilt angle increases to 45 degrees, the >> foundations need to be substantial. During one install we had our heavy PV >> trailer blow over due to high winds. We decided to have the foundations >> reviewed by an engineer and when we received the results, we had to go back >> and double our piers and strut. We had bid the job so the updates came out >> of our pocket. See: >> http://millersolar.com/MillerSolar/Portfolio/ground-mount/full_size_photos/engineered_ground_mount.JPG >> >> We are now required by the AHJ to provide a wet stamp from a structural >> engineer for every PV structure over 6 feet in height. This means every >> off-grid. We know the engineers will require massive foundations which will >> cost a lot. I am looking for a cheaper way to install these racks. I have >> not found it yet. >> >> Thanks for your input. >> >> William Miller >> >> >> At 04:37 AM 3/24/2012, you wrote: >>> William, >>> I'm attaching a picture of a system we just completed in Eleuthera >>> using DPW racks on concrete pilings. We tied the pilings and rebar >>> reinforcement into the limestone bedrock with rebar down 16 inches and >>> used 12 inch sono tubes as forms. >>> We do a lot of ground mounting since our summer work is mostly in New >>> England and snow removal is always a factor. I have two pole mounted >>> arrays at my home, but it is the most expensive option, and therefore >>> do a lot of this type of ground mounting. We also have an economical >>> "cribworks" type structure made from solid railroad ties and weighing >>> in at about 2800 lbs each that we will sometimes offer to customers in >>> off grid situations. >>> >>> Daryl >> >> >> > _______________________________________________ > List sponsored by Home Power magazine > > List Address: [email protected] > > Options & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
