Firefighters battling an 11-alarm blaze at a distribution center in South Jersey faced an unlikely foe during the fight: solar panels. A solar array with more than 7,000 photovoltaic panels lined the roof of the nearly 300,000 square-foot refrigeration facility, which served as a temporary storage center for Dietz & Watson’s deli meats and cheeses. Though environmentally sustainable and cost saving, the panels may have led to the complete destruction of the warehouse.

From 2010 to 2012, photovoltaic solar panel installations jumped nearly 300 percent, according to the Solar Energy Industries Association. And in 2012, the top 10 global solar development companies installed about 3.5 terawatts of solar panel capacity globally. Forecasts show the trend will continue to increase sharply through 2017.

A number of other factors will propel growth:
  • federal tax credits;
  • state tax credits (particularly in New Jersey, Massachusetts, Arizona and California);
  • state mandates for renewal energy development (with timelines);
  • rapid reduction in installation costs (from $8/watt to about $3-$4 currently);
  • major production increases in solar panels and cells from China, which the United States has responded to by imposing tariffs due to “dumping” (i.e., selling below production costs); and·
  • increased solar cell efficiency, from 14 percent previously to about 18 percent currently for higher quality (but still reasonable pricing). 
Additionally, commercial and industrial facilities can “lease” their land and roof space to solar development companies. They agree to purchase the solar-generated electricity at a price per kilowatt below utility charged cost. These contracts usually have a fixed price for the cost per kilowatt for 10 to 20 years at little to no cost to the facility. 

While these installations offer many positive attributes, such as helping reduce greenhouse gases and electrical costs for the users, they can pose additional risks to both property and personnel safety.
  • Fire/shock and electrocution. When there is light, the panels produce electricity, so there is no way to practically shut off the power. As such, the fire department needs to take special precautions to avoid shock and electrocution when they respond to a building fire. As noted below, they may decide to simply “protect the perimeter.”
  • Windstorm. The tilted panels found in many installations create an additional windstorm risk (e.g., panels that come loose can tumble across roofs, damage the covering and create the potential for water damage during a storm). The panel installation tends to add about 5 pounds per square foot as another dead load to the roof structure. A structural analysis needs to be performed to determine if the roof has the capacity to bear this additional load. Many of the roof installations are simply held down via a ballasted arrangement (the added weight of cement blocks or sandbags). On standing seam roofs, they are often clamped to the upper seams. Panels, particularly the tilted type, can create additional wind resistance and thus greater uplift to the roof during storms. Tilted panels also can trap more drifting snow than would be expected from a simple flat roof. There is not a generally accepted standard for calculating the additional wind or snow loads due to solar panel installations.
  • Poor quality panels. The industry has spawned many solar array installation and management companies; some are small, family-owned shops and others are very large. The same can be said for the actual panel assemblers, the materials, and quality of the panels and systems. Good quality panels will have a useful life of at least 20 years. Recently, certain Chinese-made panels started to show significant deterioration after five years. This does not mean all Chinese-made panels are low quality; the point is the quality of the installation, the panels, and the overall system can vary significantly and thus pose a hazard. 
While there is no judgment yet that the solar panels started the Dietz & Watson warehouse fire, Delanco Fire Chief Ron Holt was forced to keep firefighters from attacking the blaze from the roof because of electrocution concerns. “With all that power and energy up there, I can’t jeopardize a guy’s life for that,” Holt says. Those electrocution fears combined with concerns of a collapse forced firefighters to simply spray the building with water and foam from afar.

Ken Willette from the National Fire Protection Association, a nonprofit that develops standards for firefighting, says electrocution is one of the hazards firefighters are increasingly facing at structures where solar panels are deployed.

“Those panels, as long as there’s any kind of light present, whether it’s daylight or its electronic lamp light, will generate electricity,” he said.

A 2011 study from the Underwriters Laboratory found solar panels, being individual energy producers, could not be easily de-energized from a single point like other electric sources. 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,” Willette says.

Flooding a roof with solar panels also presents access issues that can stop firefighters from making ventilation holes used to extinguish the fire.

Willette says the issues force firefighters to take a defensive approach to fighting the flames by staying away from the building, rather than going inside and attacking the fire source. “It definitely impedes the firefighting operation, and any time you impede firefighting operation, you slow down suppression efforts,” he says.

With the continued growth of solar panels and other alternative energies, code officials, builders and developers must work with local fire departments to ensure installations are designed with firefighting in mind.

“The new paradigm is firefighters might encounter building systems they have little or no knowledge of,” Willette says. “It used to be homes and commercial buildings had roofs and walls and heating and ventilation systems that the fire service was used to dealing with. Modern technology, both in building construction and these other alternative energy systems, have changed that.”

Following are recommended risk reduction precautions.
  • Whenever possible, commercial and industrial facilities with roof-mounted solar array systems should have adequately designed and maintained fire sprinkler systems,together with acceptable housekeeping and storage array maintenance. This will help assure significant firefighter response is not required, including roof access by firefighters not being needed.
  • Standard human element programs should be in place to help assure the integrity and reliability of the sprinkler system.
  • Structural engineering analysis of the roof should be undertaken prior to a solar panel installation for both the additional wind and dead loads.
  • The local fire department should be informed of the installation and should be invited to visit the facility so they can become familiar with the location of the array (which often do not take up the entire roof area) so they can pre-plan.  

Brad Hart is senior property risk consultant for Lockton. For more information, email