More than 200 firefighters from five southern New Jersey counties responded to a massive 11-alarm fire over the Labor Day weekend at a 300,000-square-foot meat and cheese refrigeration and distribution center owned by Dietz & Watson. With sufficient manpower and equipment to fight the blaze, the ladder men still could not approach the roof—where 7,000 solar photovoltaic panels posed an electrocution hazard. As a result, the warehouse burned to the ground.
Unfortunately, this is not an isolated incident. Indeed, today, the National Fire Protection Association, a Quincy, Massachusetts-based trade group that develops standards for firefighting, is saying that solar modules may be environmentally friendly—and provide electrical backup and cost savings to building owners—however:
- The modules cannot be shut down during daylight hours (or when there is any ambient light), causing an electrocution hazard;
- They are used as habitats by all types of stinging insects, and
- their weight may make a roof unstable under the best circumstances.
Fighting the Dietz & Watson fire under bright blue skies on Sunday, September 1, Delanco Fire Chief Ron Holt told NBC-TV’s local news team, "With all that power and energy up there, I can't jeopardize a guy’s life for that,” said Holt. Those electrocution fears combined with concerns of a collapse forced firefighters to simply spray the building with water and foam from afar.
He is backed up by a 2011 study conducted by the Underwriters Laboratories (News - Alert), Inc., a safety consulting and certification company headquartered in Northbrook, Illinois, which found that—since solar panels are individual energy producers—they cannot easily be de-energized from a single point like other electric sources. Not only do they continue to generate power during daylight, but they do so even when illuminated by artificial light sources such as fire department light trucks or an exposure fire.
Researchers recommended throwing a tarp over the panels to block light, but only if crews could safely get to the area.
“Very often they’re not wired like your home, where you have a master breaker. Even if you turn the breaker off, the panels still generate electricity and you need to cover them and prevent any light from getting into them,” stated Ken Willette of NFPA's Public Fire Protection division.
Addressing the Problem
The NFPA’s 2010 study, “"Fire Fighter Safety and Emergency Response for Solar Power Systems,"recommends three tactics to minimize the danger to professionals at the scene:
- “Components are always hot!” The single most critical message is to always consider photovoltaic systems and all their components as electrically energized. The inability to power-down photovoltaic panels exposed to sunlight makes this an obvious hazard during the daytime, but it is also a potential concern at nighttime for systems equipped with battery storage.
- Operate normally, but don’t touch. Fire service personnel should follow normal tactics at structural fires involving solar power systems, but do so with awareness and understanding of exposure to energized electrical equipment.
- Size-up, identify and validate hazard. Accurate knowledge of the hazards present on the fireground is essential for minimizing personnel injuries. Identifying the type and extent of a solar power system during the emergency event size-up is critical to properly addressing the hazards they present. In particular, it is important to distinguish between a solar thermal system and a photovoltaic system, and the hazards presented by each type of system.
In addition, in recognition of the problem, several municipalities nationwide are proposing legislation. For example, the International Fire Code that the Boulder, Colorado, City Council is set to adopt calls for three-foot-wide, solar-panel-free paths from the gutters to the ridge lines on roofs and three-foot-wide paths along the ridge lines of new homes.
Boulder Chief Fire Marshal David Lowrey told the local newspaper, the Daily Camera, that he first sat down the operations team at the fire department to talk about how they work on roofs during fires. Lowrey said that firefighters felt comfortable amending the code to allow for smaller and fewer paths. The amendment allows for 30-inch paths, with the paths in the middle of roofs wherever possible. Paths on the outside edges of roofs are more dangerous, especially at night, Lowrey said.
image via Underwriters Laboratories, Inc.
Having the paths in the middle also makes it easier to cover solar panels with tarps to turn them off and reduce the risk of electric shock. Lowrey said that width gives firefighters enough room to operate, while allowing more solar panel coverage.
Local solar installers are worried that homeowners will not get the most solar mileage for their money with these changes, but they are willing to compromise. Dan Yechout, sales director of Boulder's Namaste Solar, said the amended code— which will apply to new home construction or new solar-panel installations —will still reduce the space available for solar panels. However, the industry also wants firefighters to be safe and can work with the requirements.
The 2006 fire code that the city currently uses doesn't address solar panels at all, but their growing popularity raised enough problems that newer codes took on the issue.
Edited by Ryan Sartor