[RE-wrenches] fire safety vs. fire hysteria?

Mon Jan 5 15:12:10 PST 2009

Hello Nick,

PV cells and modules only produce electricity when exposed to light. It 
sounds like someone is confusing PV modules with batteries and capacitors.

I know of no instance where firefighters let anything burn because PV 
modules were present.

The roof mounted PV array protected the roof from burning embers and 
actually prevented fire from spreading to our customer's home in the town of 
Devore in the San Bernardino Mountain foothills during the big fire of 2003.

November 2008, California Fire Safety personnel had a PV training seminar in 
Santa Monica. The information presented was accurate and the general mood 
was positive. The Santa Monica Fire Chief told fire safety personnel that 
they have to work with the PV industry on the issue of safety because the 
state of California is giving incentives for 3,000 MW of PV by 2017 and 
Santa Monica plans to have 17,000 solar roofs by 2030.

Education will help to overcome ignorance, superstition, and fear.

Joel Davidson

----- Original Message ----- 
From: "Nicholas Ponzio" <nponzio at buildingenergyus.com>
To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Sent: Monday, January 05, 2009 1:07 PM
Subject: [RE-wrenches] fire safety vs. fire hysteria?

>I just got this email forwarded from a coworker that volunteers as a 
>firefigher. Your comments are welcome:
>
> Forwarded Message:
>
> At this past Monday's Twp. Chief's meeting, I went to the presentation put 
> on by the State of NJ last night at Amwell Valley Fire concerning solar 
> panels and the danger they present to the Fire Service.
>
> The presentation lasted for about 2 1/2 hours and was what I believe time 
> well spent.  It really opened my eyes to the potential danger and problems 
> they will be for us for any dwelling fire we will encounter where they are 
> present.  I'm going to attempt to give everyone a quick snapshot of what 
> was covered.
>
> The thing to know with solar panels are that they cannot be shut down - 
> they are ALWAYS ENERGIZED.  And they are energized with up to 600 volts of 
> DC current.  For example, you cannot put an ax through them to open up a 
> roof to vent - your putting the ax through 600 volts.  If fire is 
> infringing upon solar panels on the roof it will compromise the integrity 
> of the panels.  You then have 600 volts of live electrical energy - and 
> what don't you do when you have live electrical energy? - you don't put 
> water on it.  Even if the roof burned through and the panels fell into the 
> structure, unless the panels were destroyed (de-energized) by the fire 
> and/or falling into the structure, they can still have the potential to be 
> live,they  have to be treated as such and have the potential of 600 volts 
> of DC current.
> A basic solar system consists of:  The solar panels themselves; a 
> combination box; a disconnect box; and a inverter.  The panels all feed 
> into a combination box.  The combination box (which is almost always 
> located on the roof) takes in all the energy and sends it to a disconnect 
> box.  The disconnect box takes the energy and then sends it into the 
> inverter which converts the DC current into AC current.  From there the AC 
> energy "pushes" into the structure's normal electrical system.
>
> The combination box has fuses in it that come from the solar panels 
> themselves.  If you access that box, you can pull all the fuses inside and 
> "kill" anything after the combination box.  But remember the panels are 
> still live and have up to 600 volts in them.  If you "kill" the energy at 
> the disconnect box - anything up to that box is still energized - the 
> solar panels, the combination box, the line going from the combination box 
> into the structure and into the disconnect box are all still energized. 
> The power company pulling the meter for normal service has no effect 
> whatsoever on the solar panel system - it is all still live and has up to 
> 600 volts of DC current.  The only "good" thing when it comes to the 
> disconnect box and the inverter is that they need to be co-located with 
> the normal service panel for the structure and each should be marked as 
> appropriate.
>
> Even if it's nighttime and the solar panels have not been exposed to 
> direct sunlight for several hours, they still are energized and can kill 
> you.  It is estimated that the panels would need to be covered with an 
> opaque tarp for 7-10 days before the panels will "de-energized" down to 
> minuscule levels.  (although the handouts specify that this is an option 
> for safety steps - it is not accurate per the presenter)
> In closing there are people who have greater minds and resources than we 
> do in developing a process to safely handle fires which may involve these 
> systems - such as the NFPA, OSHA, etc.  Per the presenter, the situation - 
> and these organizations, are now starting to become aware of the potential 
> problems.  So far in the State of NJ, there is no recorded injury to a 
> Firefighter being caused by coming into contact with a solar panel system. 
> Ironically, New Jersey comes in 2nd when it comes to solar panel system 
> installations in the nation, behind Califorina.
>
> The final question which was asked really put things in prospective - 
> someone asked that since Califorina is number one when it comes to Solar 
> Panel Syatem installations, "...what do their Firefighters do when a 
> structure fire involves these systems?"  Answer was "... they let it 
> burn!"
>
> Please, I'm not suggesting that we adopt this strategy.  But the reality 
> is - I really don't have an answer and it seems as if the Fire Service 
> industry, nor the Solar Panel Companies, don't either.
>
> Just - please be aware and please be careful if you roll up to a structure 
> where a solar panel system is installed - bottom line, if can kill you.
>
>
> <End Forwarded Message>
>
> Is this even possible? "Even if it's nighttime and the solar panels have 
> not been exposed to direct sunlight for several hours, they still are 
> energized and can kill you.  It is estimated that the panels would need to 
> be covered with an opaque tarp for 7-10 days before the panels will 
> "de-energized" down to minuscule levels. "
>
> And are there documented cases where firefighters let a house burn because 
> it had PV on the roof?
>
> Thanks again,
> nik
>
> -- 
>
>
> Nicholas Ponzio
> Building Energy
> 1570 South Brownell Road
> Williston, VT 05495
>
> t: 802-859-3384 x15
> f: 802-658-3982
> www.BuildingEnergyVT.com
>
> "Building Solutions for a Sustainable Future"
>
>
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