By Curt Peterson, Standard Correspondent
Many Vermonters are installing solar panels on their homes to save money on their electric bills and help preserve the environment. They may not realize covering their roofs with these heavy power generation appliances can have serious implications for the volunteer firefighters who may be called to put out a blaze.
Solar power popularity came to Vermont somewhat later than to other parts of the country, so public agencies are trying to catch up regarding training firemen to deal with fires where solar systems are present.
Jim Litevich, chief fire service training officer at the Vermont Fire Academy said his department has trained instructors to run clinics to prepare local firefighters to operate safely when they find solar panels on a blazing house.
Training will be done on a county basis, one clinic for each, and will start early in July.
According to Litevich, smoke and heat from a residential fire get trapped under the roof, increasing the temperature inside and causing the smoke to become even more dense. Firefighters usually try to create openings in the roof to vent them, and to allow water or other extinguishing materials to be applied to the fire from above.
A large array of solar panels mounted on a rooftop can inhibit the firemen’s efforts to vent the fire.
Scott Mills, chief of the Barnard Volunteer Fire Department, said the panels are usually mounted on only one side of a peaked roof, the side that faces the sun most of the time.
“It that’s the case, we can just vent through the other side that doesn’t have the panels,” he said.
Litevich agreed, but said that some roofs do have panels on both sides, and that can be a problem.
“We can vent at the ends of the roof peak,” he said, “but that is not nearly as efficient for letting the heat escape.”
Chief John Sanders of the Hartland Volunteer Fire Department said the standard minimum for roof venting is a four-square-foot hole, which he thinks might be difficult when there’s a large solar array installation. And, he said, even if the north side of a roof has no panels, wind conditions and the position of the fire within the structure might require south side venting.
Solar energy system installers, building inspectors, designers and builders are all in a learning curve regarding the firefighting implications of a rooftop array. In Weston, Massachusetts, for example, where their firemen have already been educated in fighting residential fires involving solar systems, the town requires at least three feet of access around the panels.
Of course the panels are also heavy.
“Responsible installers will recommend that the homeowner or builder compensate for the increased live load,” Litevich said. “And besides the panels, in Vermont we have to take the added weight of snow into consideration.”
Hartland’s Sanders said a fireman inside a house has a standard calculation regarding how long it will be before the roof caves in on a fire, and the added weight of the panels shortens time it is safe to stay inside. He said the same thing is true when steel roof trusses are used instead of wood — the endurance of the roof changes with materials used and added weight, such as solar panels.
According to Litevich the metal frames used to attach the arrays to the structure also become coated with ice when there is a storm, making it more dangerous for firemen to move around on the roof.
He added that the major threat to firefighters from solar power units is the potential for electrical accidents.
“Just as an example,” he said, “if the panels are mounted on one of our popular metal roofs and they short out, the entire roof becomes energized and dangerous to anyone trying to access it.”
The panels are constantly converting sunlight into electrical current, he explained. “You can’t shut off the panels. They continue to work no matter what you do. They even pick up energy from the light of the fire itself – not much, but a little.”
“And the juice coming from the panels is direct current, which is much more dangerous when you come into contact with it than alternating current, which is the form of power everything inside the house uses.”
He said there is an inverter included in every installation that converts the solar-produced direct current into safer alternating current.
“It’s important to install the inverter as close to the panels as possible,” he said. “The farther away it is, the more the threat of exposure to direct current.”
“Our first experience with a solar installation was the barn at Cobb Hill Cohousing,” Chief Sanders said. “It’s basically a shell without a lot of partitions or insulation inside, so we found out where the disconnect was and just decided to stay away from the system as much as possible.”
Litevich said there is no special equipment required when fighting fires in solar-equipped homes. The firemen already use breathing protection called air-packs, so any increased toxins that burning panels might emit do not increase the danger. And dry chemicals are always handy in case a fire is electrical, so water-conducted shock isn’t necessarily an issue.
“Should firemen use power company linemen’s gloves? Probably a good idea,” Litevich said. “But we aren’t making it a requirement. That’s a local fire department decision to be made.”
He said he knows of no fires in Vermont to date that have involved solar panel-equipped homes. The training program is an attempt to be prepared for the eventuality.
Sanders was surprised when asked about metal roofs being energized by panels if there’s a short circuit during a fire.
“I am very glad we are having the training sessions,” he said. “There’s obviously a lot that we need to learn about this issue.”
“Above all,” Litevich said, “we are recommending that local fire departments inspect all solar installations in their jurisdiction so they can make recommendations that minimize danger to firefighters and so they have a record of where shut-offs and inverters are located.”
Sanders said Hartland, for example, has no building permit process whatsoever, so the fire department finds out the details about a house being built or a solar installation after the fact.
“I’d be a strong advocate for a fire department permit requirement when a new home goes up or a rooftop solar installation is planned,” he said, “so we can provide some safety input and make a record of what we might be facing if there’s a fire.”
There are about 800 homes in Hartland, and the fire department has no record of which ones might have solar panels on their roofs. Most of the installations Sanders has seen are not attached to homes. He had a solar installer take a look at his home and he asked about a roof array.
“The agent told me they almost never recommend putting the panels on the roof,” he said. “They consider a yard array easier to install and maintain and less trouble.”
This article first appeared in the June 9, 2016 edition of the Vermont Standard.