What was the pressure rating for the modules that got sucked off the
racks? Also, is it possible that flying debris caused some of the
random location module failures?
Ray Walters
Remote Solar
On 9/14/17 1:53 PM, Jason Szumlanski wrote:
More early anecdotal data...
We are finding NO anchors pulled out of roofs, regardless of roof type
or attachment type. That is clearly not the failure point. We also see
no attachment to L-foot or L-foot to rail issues. And contrary to my
expectation, we see no t-bolt failures. What's happening? The panels
themselves are flexing (bowing) sufficiently to work their way right
out of the mid-clamps. This applies both to Unirac's older 1-inch
space clamps and newer 1/4 inch bonding mid-clamps.
This attached pictured system had panels on a north roof pitched very
slightly to the south. We had northeast hurricane winds in this area,
and the way the wind went under these panels was obviously what caused
the panels themselves to fail. This is an essentially flat roof
commercial application. It was bad luck to have the wind direction
from the northeast corner (the NW edge of the eye wall passed right
over this area). But we are seeing similar results on residential
pitched hip and gable roofs in terms of the failure mode.
What's interesting is that there is no rhyme or reason to where in the
array we see damage. I have seen absolutely no catastrophic damage on
a residential roof - just one or 2 modules mostly. And the missing
module can be on the lower edge, upper edge, or right in the middle of
the array. More often than not, the t-bolt and mid-clamp assembly is
still sitting right there in the channel of the Unirac Solarmount
rail, but a module is missing. It's quite freaky.
And much like tornado damage I have seen on TV, houses adjacent to
each other have very different fates. We have a new community (100+
homes slated for solar) with about two dozen homes completed, and just
one home had a panel pop out in the middle of an array. It was gently
deposited onto the adjacent panel with absolutely no damage and the DC
leads still connected to the microinverter.
One issue we are facing is that when panels fly off, something has to
give with the DC leads to microinverters. No panel leads have been
broken so far. In most cases, the MC4 connectors simple un-snap
somehow - no loss of crimped connectors. We have a few cases of leads
ripped out of the microinverter case completely. The microinverter
bracket is badly bent on many microinverters, indicating that there
was tremendous force until something gave up. I am extremely hesitant
to reuse these microinverters because the force on the DC input leads
must have been huge. I think we are going to insist on microinverter
replacement when replacing modules in these cases.
Hopefully I will have more, but not too much more to come. It looks
like we did very well here (as an industry). There are spotty issues,
but it's far from the catastrophe that kept me up for multiple nights
before and after Irma. Then again, many people have not returned home yet.
Jason Szumlanski
Florida Solar Design Group
On Wed, Sep 13, 2017 at 6:18 PM, Jason Szumlanski
<ja...@floridasolardesigngroup.com
<mailto:ja...@floridasolardesigngroup.com>> wrote:
Inline image 1
I'm based in Fort Myers and we cover the hardest hit areas from
Irma. We are in the "stuff" right now, so I'll make this brief
until I have more time, which might be a while. We are seeing
quite a bit of minor damage and some major damage. We're getting
calls from all dealers' customers and a couple of our own clients.
We have several homes with one or two panels dislodged. There is
no rhyme or reason. Some are middle of arrays, some on edges.
Panels are ripped right off rails, leads ripped from
microinverters. Strangely, it looks like the panel j-box
connection and MC4 connectors survived better than the
microinverter end of the DC leads. Amazingly, we have several
panels that were blown onto driveways, other roofs, and pool cages
with NO DAMAGE except frame scrapes. Very weird. We haven't seen a
shattered panel yet, but it's early.
I'm heading to a self-storage facility tomorrow where there are
three 25kw systems on different buildings. Two buildings are
unscathed. One building lost ALL of the panels apparently.
Tornado? Hard to say.
So far (other than the 25kw I have not evaluated) we have not seen
a single fastener pulled out. All of the failures are panel top
and mid clamps at this time. Anchor and rails remain intact.
Possibly installation errors? Possibly sheared off T-bolts? Hard
to tell and we may never fully know.
We generally require 48 inch spacing between anchors into trusses
for engineered systems. The pullout values are pretty high. It
looks like the attachment points into the roof are not going to be
the failure point in the systems in Florida, but there is a LOT of
work to be done still. It's going to be a very interesting few
months ahead!
Jason Szumlanski
Florida Solar Design Group
On Tue, Sep 12, 2017 at 3:09 PM, James Rudolph
<jamesrudolp...@gmail.com <mailto:jamesrudolp...@gmail.com>> wrote:
Aloha Everyone,
I was just wondering how all the PV arrays did during these
storms?
Does Florida have higher pull out values and wind designs for
their PV/H20 systems?
Is there any thing the rest of us could learn from all this?
Photos?
Mahalo Nui Loa,
*James B. Rudolph*
*Hawaii Unified*
*Director of Energy*
*ES Electrician # 10816*
*NABCEP Certified PV Installer # 091209-155*
*80*
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