As Chatham County expands its solar installations on municipal buildings, Chatham Fire officials want to make sure their firefighters are well suited and trained to tackle any potential solar photovoltaic emergency.

On Wednesday, September 4, 2024, Chatham Fire Command Staff met with members from Cherry Street Energy who installed the solar panel systems. At that meeting, command staff were briefed on the operational elements and functionality of the systems. Fire suppression methods were also evaluated should an emergency situation develop.

Deputy Chief Keith Hardin, Division Training Chief Joshua Anderson and Training Coordinator Jonathan Campbell were on site for the demonstration. Roof top Solar Photovoltaic installations pose a significant threat to firefighters. The greatest hazard presented by rooftop PV is electric shock; solar arrays should be treated as electrically charged at all times. Even systems rated for outdoor weather exposure may not be resistant to water penetration from a fire hose, and firefighter’s gloves and boots provide only limited protection against the electrical shock that could be caused by a damaged solar array. There are several methods for mitigating the risk of electric shock, but it is important to remember that none of these factors eliminates the threat entirely.

Typically, firefighters break through the roof of a building to create vertical ventilation and relieve the structure of some of the heat, smoke and gases from the fire. If there is solar on the roof, though, firefighters must take care to never damage the solar panels in the process of creating vertical ventilation, as doing so could result in electric shock (or a burn from scalding fluids in the case of solar thermal).
Placing dense tarps over solar panels reduces the light that passes through and thus reduces the electricity the modules can generate, but it is unlikely that it will block 100% of light. Even solar panels that have been covered with a tarp should be treated as electrically charged.

The foam firefighters use is thick enough to reduce the light that reaches solar panels; however, like tarps, it cannot completely block the generation of electricity within the cells.

While fires that occur at night greatly reduce the risk of electrical shock from a solar panel, the artificial light produced by a fire department light truck or potentially even by the fire itself may be enough to cause the solar system to begin producing electricity.

There are additional hazards firefighters face when addressing rooftop solar PV systems. The weight of solar panels could threaten the structural integrity of the roof, if the roof is damaged in the fire, or as the fire progresses and compromises other sections of the structure. Also, most solar panels are raised several inches above the surface of the roof, creating an ideal setting for stinging/biting insects to nest. Risks of slipping or tripping must be considered as well, any pitched roof inherently creates the risk of tripping/slipping, but firefighters should be especially cognizant of this risk when on a roof with solar PV, so as to avoid falling onto a panel and potentially damaging it and being electrically shocked. Finally, solar thermal systems present all of the same threats as PV does, except that there is no risk of electrical shock, nor is there the potential for any battery hazards. Rather, in the event that a solar thermal cell is damaged, there is a risk of being scalded with the hot fluids inside the panel.

Cherry Street Energy systems have two ways of keeping firefighters safe when responding. First, half of the system has RSD switches on every single module and the other half has the inverter close enough to the system to kill the power. Additionally, their system is able to read frequency to the power company and when the power is shut off by the main breaker or main disconnect by first responders it will automatically shut down keeping firefighters safe from inadvertent shock.

Chatham Fire prioritizes training, and this effort will ultimately keep their firefighters not only in the know of new technology but just may save a life!