[Nigel Bolton]

Having taken my young son for a long walk this evening around Tiverton, it is interesting to see the local Council is installing large numbers of solar panels to the roofs of many council properties, maybe in order to beat the cut in tarriff paid for those that 'add' power to the National Grid. They are generally arranged in arrays of 'four-by-two', or 'eight-by-two', and as one would expect, on the southern or southwesterly aspect of the properties, where possible.

However, one thing does strike me. These are adjoined flat panels anchored to roofs, with a gap in between the panels and the roof tiles or slates, such that the wind can get underneath them

Can someone assure me that these panels can withstand wind speeds of 80 to 100 miles an hour, that they won't become airbourne missiles during a storm, and that they don't drag half the roof with them if they do detatch. I am sure the ground work has been done, such that the structures can withstand a one in one hundred year gust, or whatever neccesary parameters that manufacturers and installers use, but I cannot help thinking that during the next strong storm, some of these panels and related debris may become a significant threat to life and property.

I would also wonder what would happen to these panels, if there is another tornado similar in size, longevity and strength to the one that affected Birmingham back in 2005, or Selsey back in 1998, occurring within a built up area.

N.

[grahamread]

Quote

As far as I am aware they are just anchored to the tiles

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Solar PV panels are bolted to a frame. The frame is bolted to the main roof timbers via a steel support that runs under the tiles and bolts onto the timbers that are holding the roof up. So it's more than likely if a panel came off something *really* bad is happening to the roof anyway - like a tornado. In which case there'll be plenty of tiles flying all over as well.

The worry is that some panels haven't been installed correctly - such as sticking above the roof line / too close to the gutter or roof edge; or bolted onto thin rooft timber that hasn't been strengthened.

In theory a PV installer should run wind loading calcs to ensure the roof can take the added weight. I bet most don't though.

Added: Generally house insurers consider solar PV as part of the house fabric and covered by building insurance (at least mine did)

This post has been edited by grahamread: 11 March 2012 - 22:49

[Peter H]

AIUI the gap has to be there because to get best efficiency solar panels need to be below 25C(?) so the air needs to circulate - indeed I have heard we'll do surprisingly well in the UK because though we can be down on sun we don't lose out due to the heat (that will be the day...) . oh, and the whole house will have to go to get ours off the roof, they're really part of the house...

So, only if the roof becomes a missile do the panels likewise.

This post has been edited by Peter H: 11 March 2012 - 23:04