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Permalink Reply by Jack/dt on April 2, 2011 at 11:00am

The entire (front facing) roof is a large PhotoVoltaic Arrary. This system looks like it provides more electric than needed to run the house so it feeds the excess back into the grid. [if the house is oriented east/west then the entire roof most likely is a PVA]

Issue here is that during daylight hours it IS producing electricity (looks like local power lines may be underground), and given that the entire front roof (at least) is a PVA it has to be considered that the may be a battery storage system in the house for non-producing periods (equally probably is the presence of a generator as well.)

Construction-wise it looks new and most likely light weight construction. It appears to be on a slab as opposed to a basement and it also appears that we're looking at the Charlie side (no walkway to the door, grill left of door suggests back of the house). To the right of the door is a tall Palladium style window which suggest the Bravo side, first floor is open to the second, which means large open spaces, truss and Gluelam joist-type situatio

Back to TCO, daytime ops means extreme caution operating on the roof, vertical ventilation really has to be ignored (unless intimately understood) because no matter what is going on at the discharge end of the system the PVA is continuously producing electricity. Night time ops the system isn't operational but, not sure how much electricity could be produced when the house is lit up by scene lights.

Summary- PVA producing copious amounts of electricity, possible battery storage system, possible generator, roof top ops complicated (at best), lightweight construction material/techniques, rapid fire/smoke spread and possible early collapse.

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Permalink Reply by Wade Seely on April 2, 2011 at 11:18am

What Jack said.

The only thing that I would add is that the weight of the panels needs to be considered when thinking about a possbile collapse when coupled with the light weight construction.

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Permalink Reply by Sparky3317 on April 2, 2011 at 11:35am

How would you complete a vertical vent on this house?

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Permalink Reply by Wade Seely on April 2, 2011 at 12:08pm

Here is a link about this topic that sheds some light on how dangerous these panels can be, unfortunatly it doesn't say how to circumvent the problem.

http://www.emtbravo.net/index.php/topic/29407-safety-info-solar-pan...

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Permalink Reply by Wade Seely on April 2, 2011 at 12:12pm

If the roof is completley covered in panels the answer is you don't. However, in a lot of cases they only have the panels on the back side of the house so that the front still looks cosmetically appealing. Even if only half the roof is covered in panels you still need to make sur that the roof is stable, asthe weight of the panles on the other side could still pose a signifigant collapse hazaed. Whatever you do dont' mess with the panels themselves because even at night they can carry enough volatge to kill you.

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Permalink Reply by Jack/dt on April 2, 2011 at 12:41pm

Solar cells work when solar energy hits the panels/collectors and that energy is changed into electricity (simplified granted). When there is NO sunlight (night time) there is NO electricity produced by the system (other than, as I suggested earlier, scene lighting might create electricity, a possibility).

The link you provided showed up in another discussion here some time back. A PVA is built to collect sunlight, turn it into electricity and/or store it in a battery storage system. The PVA is NOT a storage system, there are no capacitors to store/build up charge and it produces Direct Current electricity only when sunlight is shining (and through some cloud cover.)

From here - http://www.swansolar.com/faq/#support

Can my roof support the weight of the solar array?

Solar panels and the associated mounting equipment will add very little load to your roof. Typically the solar array will add less than 3lbs/ft2 of load to the roof. Some older homes may require some structural work prior to installing the system but this is very rare. If needed a more detailed engineering assessment will be conducted.

This is NOT a do-it-yourself project and unless paranoid to a degree that you are completely off all "grids", permits, inspections and approvals ARE going to be needed, and a determination will be made if your existing roof can support the additional weight.

But...in a lightweight constructed home, with the additional weight (which could easily be a snow load, or a PVA), loss of structural integrity as a result of flame/heat impingement on the assembly, WITH the additional weight could mean a faster collapse, a more widespread collapse, or both.

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Permalink Reply by Wade Seely on April 2, 2011 at 1:22pm

Jack

Thanks for the correction on the electrical hazard. I was going by what the article said, do to the fact hat I have limited knowledge on solar panels. That being said I will have to do more research on them. As for the weight factor, I realize that under normal conditons that even light weight construction would be able to support the load and that permits and other documentation would be needed. My posts on the weight factor were using the assumption that there was fire impingment allowing for the added weight to play a factor.

TCSS

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