One new tool is a video produced and narrated by a captain for the San Jose Fire Department. “Being a firefighter, I understand what firefighters want to know,” said Matt Paiss.
The video gives working firefighters practical advice for minimizing the risk of electrocution as they clamber on a fiery roof that holds photovoltaic (PV) panels.
“There are some high voltage hazards,” said Paiss. “My thrust is to teach them what can hurt them. The last thing we want is a firefighter getting shocked and falling off a roof.”
Initially, the city of San Jose distributed 500 copies of the video. It is also available on YouTube.
With a house fire, a firefighter’s inclination is to use an ax or chainsaw to open up the roof and let the rising hot smoke and gases escape. But a rooftop PV system curbs that strategy because of the risk of an electric shock if you chop through a solar panel.
A set of guidelines by the office of the California Fire Marshal dictates that solar panel installers leave a 3-foot clearance around a grid of panels to give firefighters an opportunity to poke that hole in the roof. The 2008 document, “Solar Photovoltaic Installation Guideline,” was developed by a task force that included Paiss. View here.
Another house-fire standard procedure is to shut off circuit breakers. But with the solar panel risk, according to the San Jose video, it’s not enough to shut off the main electrical panel. During daylight hours, there will still be direct current running in wires between solar modules and a solar inverter panel that is likely to be in the garage or basement, near the main electrical panel.
The San Jose video advises fire crews to lay tarps over solar panels, when practical, to block sunlight and stop this current.
Paiss has been advocating that manufacturers and installers, as they develop the next generation of solar modules, design internal switches in the modules or inverters to shut off power to solar inverters and include arcing protections.
“Everything with the new green building standards is pretty much new to everyone in the fire system,” said Vickie Sakamoto, division chief for the state Office of the Fire Marshal. “The technology of building materials is changing.”
“We want the systems to be safe and they can be safer,” said Paiss, who has solar modules at his house. “The manufacturers are acknowledging our concerns … I’m optimistic because I understand the strength that public safety has on code development.”
Paiss, who holds associate degrees in solar energy technology and fire science from Cabrillo College, said firefighters (and insurers and manufacturers) need a clearinghouse of information about the few fires involving solar modules.
Paiss’s advocacy includes the video, an appearance at a solar industry conference in Germany in September and a San Jose training session for firefighters in August. The latter drew 80 firefighters from the San Francisco Bay Area and as far away as Soledad and Bakersfield. It included a visit to the roof of Gunderson High School in San Jose to give firefighters a closeup look at solar panels there. Paiss has also provided PV safety training to more than a dozen Bay Area fire departments.
San Jose, with an estimated 1,200 houses with rooftop solar systems, has not had a fire involving solar technology. Paiss said there was some discussion at the recent San Jose seminar about a Bakersfield solar panel fire that was caused by arcing. There was minor damage in the fire on the metal roof of a Target store April 5.
An electrical wiring problem caused the solar panels to catch fire on April 5, said Michael Nicholas, an engineer for the Kern County Fire Department.
“The impact to our department is that it was most evident that we had to increase the awareness of solar panels and some of the risks posed to our first responders,” Nicholas said.
Lance Howland can be reached at firstname.lastname@example.org