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Joined: Jun 2004
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Here is one quote I read...

"The fire broke out at the Dietz & Watson cold storage facility on Cooperstown Road in Delanco, Burlington County, N.J. around 1:30 p.m. Sunday and caused the roof, lined with thousands of solar panels, to collapse within hours. Thick, black smoke could be seen billowing from the facility miles away."

The roof which is the size of 5 football fields was completely covered with 7000 panels and firefighters could not go on the roof or in the building to fight this fire.

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I don't believe the report is accurate, or complete.

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You telling me Reno that mondern day journelism that has access to so much more data is report half truths and filling in the blanks to make it sound good instead of reporting just the facts so we can decide?... Was it reported by Fox News...?


"Live Awesome!" - Kevin Carosa
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http://www.fireengineering.com/news...s-it-can-work-around-warehouse-fire.html

If you look with Google it is well covered with panels. The firefighters were worried they would be electrocuted if they went up to ventilate the roof. On a large bldg like this it is important to cut a hole or trench cut the roof to contain the fire to one area. Having been in the fire service as well as an electrician, I would have gone on the roof, but I can understand firefighters not wanting to get near those panels. With as many panels as there were, during a sunny day, lots of volts & amps.and no meter to pull to shut it all down.

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As far as I know, there has not been a definitive cause released for this fire.

Water pressure and availability was an issue, based on article I read. Yes, the solar panels were an 'issue'. The Fire Chief refused to allow any firefighters onto the roof because of the panels.

It was reported as an eleven (11) alarm fire.

Dietz & Watson released comments that they will continue to take care of their customers and employees.


John
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Problem of not venting the roof is cant let the smoke out


"Live Awesome!" - Kevin Carosa
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When we built one of the big exhibition buildings in Chicago, we installed dozens of spring-loaded roof hatches that would pop open on command from the FACP when the firemen wanted the space ventilated.
You can see them spaced in a neat grid on GoogleEarth if you look at the white building with the rounded SE corner right where I-55 and US-41 meet.
It's around 41 degrees 51' North and 87 degrees 36.5' West.


Ghost307
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NBC News 10 out of Philapelphia has an update Mon. AM 9/9/13 that there are still flare-ups at the site.

Hot spots under the colapsed roof are not accessable, and the plan is to let it burn out.

I am not aware of a definite cause as of yet.


John
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John
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Thanks for the update link.

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It will be interesting to see what the final determination of a cause for this fire is.



John
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I posted a local (to me) fire that involved solar panels here ("Question") in Alt. Energy.


John
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Originally Posted by HotLine1
I posted a local (to me) fire that involved solar panels here ("Question") in Alt. Energy.


Question??? What was the final cause of that fire?

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Laast word was possibility of condensation build-up in combiner box. Possible bad sealing from interior to exterior within raceway. Not ruled as definitive cause.


John
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Update:
The remaining rancid, rotten meat and other food products clean up is scheduled to be completed today 9/25/13

There has been no cause announced to date.



John
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http://www.youtube.com/watch?v=IeHxHTi1TJ4
Note solar panels covering most of the roof

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I can say that all the large comm solar installs in the Twp I work in do not cover antwhere near 100% of the roof.

Clear 'aisles' for lack of a better description are required, and addressed during the plan review process.

Yes, panels do present various issues for firefighters. We request that all comm jobs have a facility walk-thru with the firefighters, both officers and regular firefighters. Tours are arranged via the solar contractors, and the FD.

I would be curious as to the cause of the California resi fire that is in one video.



John
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Seams like a connector like this http://www.andersonpower.com/products/multipole-sb.html mounted on the side of each panel would isolate the panel from the house. Equipped with a handle (They make one for that connector) that could be opened with a Pike pole (a firefighters tool use to pull ceilings) the fire fighter could operate from a distance and disconnect all the panels from the system. Good for residential aps but may be impracticable for commercial aps. I like the carport mounted panels used on some commercial locations. Gets them off the roof, easy to isolate and does not interfere with firefighting or re-roofing.

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In watching the home fire video, you can see the roof venting was done on the side of the roof without the panels.

A UL video I watched recommends that solar panels can be covered to de-energize the system during a fire.

Those fire fighters did not cover the panels they were working near. I can't imagine the fire department taking the time cover panels or even start disconnecting a system when they arrive at a fully engulfed fire situation. They need to concentrate on putting out the fire as trained, not spend valuable time trying to disconnect a solar system.

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IMHO, the structure under the panels (visable) seems to have been fully active, as flames were licking over the gutter. Venting there would create a more hazardous situation.

As to 'covering' the panels, yes that will either kill or reduce the output dramatically, but....who carries enough tarps?? We (myself & local FD) had that conversation. Another 'idae' that was thrown around was using foam, but I heard of no more comments about that.

It would be interesting if Trumpy would jump in here with his opinion, as he is/was in the fire service.



John
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Here is a link to a 150 page study done by UL on Firefighter Safety and Photovoltaic Installations Research Project...

http://www.ul.com/global/documents/.../fireservice/PV-FF_SafetyFinalReport.pdf

I have not review it in awhile but they say foam will not help much I believe...

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Hi John,
Personally, I have to agree with the Fire Chief in this situation, I think he made the right call there.
Not in any way because of any perceived electrical hazard, but one of the golden rules of firefighting is to never get yourself or others into a position that can't be escaped from.

Also, with the amount of weight already on the roof (with the PV panels) and the likelihood of collapse caused by heat from the fire below compromising the roof structure, I'm pretty certain I wouldn't put my fellow FF's in that situation either, it's a dangerous enough occupation as it is, without making it worse with bad decisions.

Having been involved with fire investigation in the past, I can say that any verdict as to the cause can take ages, some fires are easy to work out what started them, others can take a LOT of pain-staking work (I've had a pair of tweezers in my hands on the odd job), but that is what you have to do, instead of putting it in the "too hard" basket".

This is why it REALLY annoys me when I read somewhere that some "fire investigator" deems a fire to be started by electricity alone, "Ohhh, it's electrical!" they say, bollocks, 9 times out of 10, this couldn't be further from the truth, electricity itself, can't start a fire, there has to be something like negligence, criminal intent or plain stupidity to cause that electricity to start that fire.

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John,

I heard about that fire and it did make the news up north here, but not much in the way of follow up news. Thanks for keeping us posted here. I have a very large PV system about to start in 1 of my towns. They are looking to cover a large roof with about 1,000-2,000 panels for 2-3 systems. Each system with produce 400 amps at 480 volts 3 phase. I can't wait to see this one.

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Before panels go on the roof, it must be verified and in most cases reenforced to carry the load, safely. Especially in snowy areas. It should have gone for a building review prior to permitting and construction.


"Live Awesome!" - Kevin Carosa
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A bigger issue is whether the building faces high wind conditions.

PV arrays become vast sails that can produce lift.

Instead of plunging down it may take of like Dorothy! (Wizard of Oz)

Personally, I think that PV only makes sense if done down low -- never on roof tops. Eventually the casualties will mount to such a point that today's folly will be stopped.

Between fire hazards, roof falls, and sailing effects... it's the wrong place to use. It's inspired by Sci Fi writing, by those ignorant of engineering issues.

As I've posted before, most of the money for PV power is wasted on hazardous labor -- and difficult NON-UNIFORM mounting situations. There are so many different roofs to anchor to, it's tricky to get them all correct.

In this mania, there are sure to be no end of faulty installations which will haunt America for years. In the fullness of time, PV arrays will be seen as a negative during home sales: roof leaks!

The nation would've been much better off if vast arrays were merely parked in New Mexico. There are high deserts there with no one on them -- and not much wildlife, either.

They could've been, should've been, plopped down in one vast complex -- sort of a TVA or BPA for our times.

In the long run, in the larger picture, the true market for PV power is electrolysis. By generating hydrogen gas this way all of the other issues drop away.

It is obvious, though, that ultra-cheap methane makes PV sourced hydrogen gas uneconomic.

So the market for PV energy is going to be saturated quicker than you might think.

I'm in California. The only reason for PV economics is vicious government policy -- that is taxation at the power meter. We're forced to pay $0.45/ kWHr! If your home is big enough -- and the climate is warm -- your power bills go into orbit.

This billing rate has absolutely no relation to the actual cost of power to the utilities. It's a sumptuary tax forced down from above by politicians.

It's obviously ruined the upgrade after market hereabouts. Everyone is tossing out their hot tubs -- and all the rest.


Tesla
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Quote
Everyone is tossing out their hot tubs


Now that is a place where solar power really makes a difference. You just use low tech pool style water heating collectors and you can boil that sucker if you aren't careful.
If you glaze them or just cover the collector with Visqueen, you can increase cold day performance by at least 50%.


Greg Fretwell
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Tesla,

You talk about sailing away as Dorthy from the Wizard of OZ, well we were working on a large neon sign once upon a time ago, with 3 people. I was on the top part of the sign, my foreman was in the middle and the apprentice was on the bottom. We started to remove the large piece of plexiglass cover, we were on a very busy and windy highway, I kept asking all my men, "Are you OK, shall we keep going?" They both said, "OK so far." So we would pull out the cover farther and farther, when finally it was just about to loosen free. Next thing you know, you hear the apprentice yelling, "OH, Oh, I'm flying away!" The wind caught the large sign, and was trying to blow him off the ladder and sail him away. We were only about 15-20' off the ground, but we didn't want to see anyone get hurt. My foreman and I grab the sign as hard as we could to keep the apprentice from flying away. We got it and him down to the ground safely and continued to fix the sign, get it lit back up and replace the plexiglass.

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In Florida you need engineering to put PV on a roof.
In my area it is the 160mph wind code


Greg Fretwell
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Greg...

The typical stanchion is PRIMARILY designed to resist gravity.

I'm of the opinion that very, very, few are designed to combat sail effect.

Further, as you know from Florida's 'wind issue' that the WHOLE dang roof may do a 'Dorothy' if not tied down.

These are issues that are very hard to deal with -- after the dang house is old work.

I can see massive lawsuits, just around the corner, that will wipe out 'solar electric' players. Kind of like the move against aluminum siding. -- See "Tin Men" -- funny as all get out, BTW.



Tesla
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The basic design criteria in Florida is if the roof flies away, it is taking the foundation with it.


Greg Fretwell
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Tesla:
All solar installs, from resi roof (dingle family) to the largest comm REQUIRE engineering submittals. For roof loading, and wind uplift.

The majority of the large comm jobs use 'self-ballasted' racking for the panels. (Concrete blocks)

Our Building Inspectors verify the 'spec' on the blocks, including the weights of the block. You may be surprised on reading some of the red tags.


John
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Quote
The majority of the large comm jobs use 'self-ballasted' racking for the panels. (Concrete blocks)


Doesn't that just make it a bigger missile when it goes? wink
Everything here is strapped down


Greg Fretwell
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Maybe if we get a real 'cane like you guys in Fla., we will see if the self-ballasted systems work.

I'll have to hunt up a pic.


John
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It wasn't that long ago that you saw 70-80. There is a lot of uplift, even in a cat 1.


Greg Fretwell
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It's the gusts that do you in.

Just a few seconds beyond the critical value begin a cascade of failure.

PV really doesn't have a disconnect switch -- from the point of view of firemen.

I expect that they'll have to sport some darkening foam that can be shot up to be-cloud the cells.

At this time, most departments are behind the curve.


Tesla
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I expect that if we have a few more big fires involving PV, there will be a panel level shunt trip in the listing standard that shuts down all output from each one internally.
It would be a pain to go up and reset it but if you really had a fire, you would want to inspect them for damage anyway.

I suppose it could just be a relay controlled from the ground tho.


Greg Fretwell
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I'm thinking...

Last edited by Tesla; 11/18/13 03:51 AM.

Tesla
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I'm still thinking...


Tesla
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Greg:
From Sandy ('13) and Irene ('12) and the Nor'easters we have had, I am aware of no issues.

Common problems at a few sites are bird related droppings, and a few panels that had been vandalized by rock throwers.



John
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Isn't the 2014 NEC going to require a "quick disconnect" for all new PV systems? I thought that I read it somewhere.

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Originally Posted by harold endean
Isn't the 2014 NEC going to require a "quick disconnect" for all new PV systems? I thought that I read it somewhere.


Hi Harold...this is from the 2014 NEC draft...

690.12 PV Arrays on Buildings Response to Emergency
Shutdown. . For PV Systems installed on roofs of buildings,
photovoltaic source circuits shall be deenergized from
all sources within 10 seconds of when emergency shutdown
is initiated or when the PV power source disconnecting
means is opened. When the source circuits are deenergized,
the maximum voltage at the module and module conductors
shall be 80 volts.

And here is a link to a piece of equipment that will do the job...

http://www.solarbos.com/products/combiner-boxes/contactor-combiners

shortcircuit


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80 volts max? That gonna run costs up. More circuits bigger wire. It's good thing I'm not planning putting my systems of roofs. Most if not all of my systems are exceed 80 volts at the modules


"Live Awesome!" - Kevin Carosa
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This is 2014 NEC 690.12 from the softbound PDF:

690.12 Rapid Shutdown of PV Systems on Buildings.
PV system circuits installed on or in buildings shall include
a rapid shutdown function that controls specific conductors
in accordance with 690.12(1) through (5) as follows.
(1) Requirements for controlled conductors shall apply
only to PV system conductors of more than 1.5 m (5 ft)
in length inside a building, or more than 3 m (10 ft)
from a PV array.
(2) Controlled conductors shall be limited to not more than
30 volts and 240 volt-amperes within 10 seconds of
rapid shutdown initiation.
(3) Voltage and power shall be measured between any two
conductors and between any conductor and ground.
(4) The rapid shutdown initiation methods shall be labeled
in accordance with 690.56(B).
(5) Equipment that performs the rapid shutdown shall be
listed and identified.

I have a lot of reading to do, starting thru the NFPA version of the '14 Changes.


John
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So the 5 and 10 foot rule is how the book reads? I have seen both proposals...but have not bought a 2014 NEC yet...

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I have the '14 NFPA version with te PDF, and the Changes package.

Could not get it thru Mr Bill, as the PDF is 'NFPA Only'

I really miss the CD/DVD formats, but it seems they are gone by the wayside since '08


John
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Shortcircuit,

That quick disconnect looks very nice. I always thought that there should be a way of disconnecting the current coming down from the roof without having to climb up there.

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This new quick disconnect will only have to be installed on the full DC type systems where the send the DC down from the roof to the inverters right?

If the system on the roof has the micro inverters, would the quick disconnect be required? After all if you interrupt the AC going up to the roof, the inverter stops the current right there at the solar panel.

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Originally Posted by harold endean
This new quick disconnect will only have to be installed on the full DC type systems where the send the DC down from the roof to the inverters right?


Yes on the DC systems with photovoltaic output circuits leaving the array. The large arrays on rooftops will probably have many of the shunt trip combiner boxes.

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Originally Posted by harold endean
If the system on the roof has the micro inverters, would the quick disconnect be required? After all if you interrupt the AC going up to the roof, the inverter stops the current right there at the solar panel.


With the micro inverter systems when the AC is shut down, it kills the power right to the individual panel. The micro inverter systems are a best choice for fire fighters.

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There's a nice graphic in the 'Changes' book. I'll see if I can scan it & post it here; no promises thou.


John
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