PV panels
because of the pitch of the roof or the way they are mounted, and they are slick surfaces. This is a physical problem to start with, but also significant damage will be done by walking on them.
Another problem is caused by the weight of solar cells on a roof. A 5kW installation with 20 panels can weigh 900lbs, adding to the hazard of roof collapse if a fire is located under the roof. In addition, a growing segment of the industry is using ‘solar shingles’, which are really solar cells although they look like ordinary shingles.
Voltage issues
Industrial installations will typically use higher voltages and may be in megawatt (mW) capacity. Added to that is the fact that solar cells are always ‘on’, as long as there is sunlight. Responders may turn off control panels and electrical switches, but power is still being generated and voltage is present. Even at night, adjacent lighting can generate some voltage. Some fire departments have taken to carrying covers to be placed on the cells to minimise the electrical hazard to responders. The voltages involved can be up to 150 Vdc (although some systems go up to 600 Vdc), and there are no instruments, unlike those for AC voltages, to warn the firefighter. Also, the wattage available varies with the size of the cell area, so a solar panel should
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www.frmjournal.com OCTOBER 2019
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