William,
Looking closely at your picture of the rack failure with
the tower in the background, it looks like there is some
discoloration/staining/rust? at the main spar center bolt. I went back
to some of my older installs to discover this happening and on a couple
of them was able to rock the rack E-W more than I should have been able
to. I think this was discussed on the list a ways back, you may be
aware of it that that center bolt needs to be reefed on to prevent any
movement. If the hole in that main spar was compromised and the rack
was able to shift back and forth...not sure if that would contribute to
failure of the kind you experienced.
Bill
Feather River Solar Electric
Bill Battagin, Owner
4291 Nelson St.
Taylorsville, CA 95983
530.284.7849
CA Lic 874049
www.frenergy.net
On 1/10/2017 5:26 PM, William Miller wrote:
Ray:
I can't say I have a solution to your problem, but I can share some photos
of two similar failures in case you can glean any information from them.
See:
http://www.millersolar.com/MillerSolar/case_studies/Wind_damage/_wind_dama
ge.html
The first failure is a Zomeworks. On the same exact spot we tried a DPW
TOP. Neither could withstand a funnel effect provided by the topography.
At the same location we installed a roof mount as well that has never
failed (to my knowledge, we don't service that customer anymore).
I think if you have terrain that is tilted in the correct direction a
mount that hugs the ground is best. That is a lay opinion, however.
William
Lic 773985
millersolar.com
805-438-5600
-----Original Message-----
From: RE-wrenches [mailto:[email protected]] On
Behalf Of Ray Walters
Sent: Tuesday, January 10, 2017 2:31 PM
To: RE-wrenches <[email protected]>
Subject: [RE-wrenches] Solar World Wind Damage
Greetings All;
I just had the dreaded call from one of my higher profile commercial
clients: a remote radio repeater station had modules ripped off the frame
by high winds.
Two SW285s were damaged. The wind was strong enough to rip right through
the aluminum side rails. We had used the proper stainless 1/4"
bolt hardware with washers on the inside, etc. All the hardware was still
tight, it just tore the aluminum past the washers. This is not a top down
clamp system, but uses bolts through the mounting holes on the back of the
module. This was all on a DP&W rack with high wind option.
In 20 years in business, I've never seen that happen. Is there a contact
at Solar World? I'm not getting through on the tech support line I have.
First, I need to know what the wind rating is on the modules blowing from
the back side, and Second, a suggested fix for the remaining modules.
One module was completely ripped from the frame and thrown 30 yds (total
destruction), a 2nd one has cracks in the Aluminum, but has not let go
yet. I was thinking of adding some angle aluminum on the inside to beef
it up. IMHO, the frames are pretty thin aluminum compared to older
modules. I'll share some pics when available.
As always thanks in advance for your comments,
--
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
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