Monday, October 25, 2010

Think About It!


A fire-related emergency involving a structure with one or more solar panels would not be considered an unlikely or even rare occurrence in the United States anymore. There are, for the most part, two different 'types' of solar panels that firefighters need to be aware of, as well as a few basic hazards associated with each. Regardless of what type, either thermal or photovoltaic, the first unit on scene must relay the presence of solar panels to all incoming units.

Before I get started, let me state that I am just discussing the basic hazards we should all be aware of while operating near roof mounted solar panel systems, and am in no way an expert on these systems.

Thermal systems, for the most part, use solar panels to collect heat from the sun, and transfers it to the water that runs through the piping. This hot water feeds down to a storage tank, and acts as a pre-heater to the house's existing water heater. Some of the hazards that firefighters need to be aware of while operating near this type of panel are (but not limited to): tripping/slipping, structural collapse due to extra weight, flame spread, inhalation issues (from burning panel materials*) and hot fluid scalds. Fires in/near this type of system can be extinguished with normal tactical and strategic approaches (water).

Photovoltaic systems use the solar panel's cells to convert sunlight into direct current (DC) electricity. To provide electricity, these systems include several pieces of equipment in addition to the solar panels. The additional components typically include a charge controller, an inverter (to convert the DC current to household AC current), heavy cables, wiring, and some form of electricity storage (typically batteries).
Some of the hazards that firefighters need to be aware of while operating near this type of system are (but not limited to): tripping/slipping, structural collapse due to extra weight, flame spread, inhalation issues (from burning panel materials*), and most importantly: severe electrical shock and battery hazards. Be aware that a solar panel exposed to any sunlight is always "on" and the system remains energized. DAYLIGHT = DANGER.  The only way to eliminate the electrical output of a panel is to cover it with 100% light-blocking material (heavy tarps). Fires in/near this type of system should be attacked similarly to any piece of electrically energized equipment.

During roof operations, firefighters will need to remain aware of the added weight of the solar panels on a roof that may be weakened by fire below. An array of solar panels may also prevent direct access to the section of roof providing the optimum point of vertical ventilation. Under no circumstances should solar panels be cut or damaged to perform vertical ventilation.  -Keith

*Panels are made up of many materials that may include gallium arsenide, phosphorous, and cadmium telluride that, when exposed to fire conditions, introduces potentially dangerous levels of cadmium, a know carcinogen.

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