By Brian Butler
We are currently starting to see more photovoltaic (PV) solar panels on the roofs in urban area housing, especially in New Jersey which has the most solar panels per square mile in the U.S. PV solar panels will be problematic when performing roof ventilation and ladder placement. In addition, the panels are always energized and their added weight may contribute to and accelerate collapse.
Solar panels cannot realistically be deenergized during fire operations unless correctly powered down and all panels completely covered with appropriate canvas or 100 percent light-blocking tarps. Firefighters are going to have to CAREFULLY deal with their presence and focus on isolation over deenergizing. PV solar panels are always live and can easily electrocute a complacent firefighter using a hand tool and roof ladder in their vicinity.
The primary concerns for the presence of panels during attic fires vary from electrocution, roof ventilation and the weight of the panels contributing to collapse. An array of panels weighting 150 lbs each, and carrying voltage between 500-1000 volts DC current are dangers the IC must consider. Another concern is overhaul. The electrical components (solar PV conduits and wiring) may extend into the attic space. When shutting off the breaker to secure the buildings power prior to opening up, hooks are being extended into an area that is potentially energized.
TIP: Truck firemen assigned to the roof and operating saws must avoid the panels, conduit, and wiring area when cutting the vent-h***. If panels are starting to burn, the acrid smoke is deadly and contains additional hazardous material. Wear an SCBA when solar panels are present! (Usually, I am against SCBA's on the roof, but not for solar panels)
The presence of 20 PV solar panels on a lightweight truss roof with fire in the attic or cockloft will be adding 3000 lbs to the roof, plus the weight of the firemen. There could be several inches of snow covering an array of solar panels on the roof at a top floor fire in a SFD with unsuspecting firemen below unaware of this additional weight.
IMPORTANT: Heavy solar panels sliding off the roof can kill firefighters below. Safety officers must address the potential for runaway panels at large fires, and keep those areas clear.
(Above) Solar panels are usually placed on one side of the roof, the side closest to achieving 180′ south. This location helps capture the maximum amount of thermal energy throughout the year. Vertical ventilation for an attic or cockloft fire can still be achieved by using the opposite side of the roof well below the ridge using extreme CAUTION to avoid conduits, wiring systems and the panels themselves. If that’s not effective or possible, the presence of a firewall combined with good horizontal ventilation might save the exposures.
Approximately 7% of solar panels are installed incorrectly.
Although rare occurrences, solar panels have started attic fires.
Another concern with solar power are solar shingles on the roof. Though not as common as PV panels, it eliminates altogether the possibility of venting the roof at top floor fires.
Photo by Brian Butler
For steep pitch roofs, work from an aerial device and vent the opposite side where no panels are present.
All firefighters should attend a course on solar panels to become familiar with them. The technology is always changing and the dangers are always going to be there for the duration of their careers.