A report was commissioned by the government to examine risks to roofs from fires involving PV panels.
Published in February,, external it warned that “roof performance in a fire scenario” could be altered by their presence.
Panels can trap heat closer to the roof surface, it said, increasing temperatures and “potentially accelerating fire spread”.
But fire spread “tends to cease after a relatively short distance” once it was no longer underneath PV panels.
Factors affecting the spread of flames in a fire involving solar panels included “panel elevation, inclination, mounting systems, wind, and spacing”, it added, while also calling for further research and a “comprehensive approach”.
It recommended that “focus should be placed on mitigating fire spread and roof penetration”, by leaving gaps between arrays of PV panels and ensuring roof surfaces were not made of combustible materials.
Wilkins said that during fire incidents, PV panels posed an electrical risk to firefighters, because “you can’t turn off the sun so it’s still going to be collecting that power”.
He spoke of a conversation with one firefighter who, following a review of local solar panel fires, said they were often caused by a mismatch of the PV panel itself and the wiring system.
“If they’re not fully compatible, they become loose and that’s where we get arcing and that’s where we have potential for fires.”
Sometimes, cables produced by the panel manufacturer were not used, he said, because an alternative was cheaper.
