Note: The information contained in this periodical weblog may be outdated. This was my personal weblog published before January 1, 2015. Since then I have been the co-owner and Principal Solar Designer at Florida Solar Design Group.

Solar Panels in Hurricane Prone Southwest Florida

Solar salespeople don’t like to talk about hurricanes when discussing solar panels with prospective customers. With hurricane season in full swing, there are understandable concerns about high winds and their effect on solar panels. The truth is that there is not much to fear. Hurricane prone Southwest Florida has seen its share of storm activity over the years, so there is some precedent for solar panel performance here.

Collier Wind Map Shows Challenges for Solar Panels
Collier Wind Map Shows Challenges for Solar Panels

Under the Florida Building Code (FBC), solar panel attachments must meet very stringent wind uplift requirements. In Collier County, for example, the maximum ultimate design wind speed we face is 172 mph for a typical residential solar installation (on Marco Island). Virtually all of Naples, FL requires a design wind speed of 170 mph. That kind of wind easily results in wind uplift forces that can exceed 50 pounds per square foot!

To meet requirements in ASCE 7-10 as required by the current code (FBC 2010), the number of roof attachments is selected based on the wind uplift of the solar array and the ability of each attachment to resist the point loads imposed by the fastener(s). Typical fasteners are lag screws that provide excellent wind uplift capability. For example, a single 5/16″ lag screw in a typical Southern Yellow Pine truss can provide upwards of 600 pounds of pull out strength in a 2×4 top chord.

Because of the stringent building code requirements, solar panels typically stay with the roof in a high wind event. It is not uncommon to see shingles lost from a roof surrounding the area where solar panels were installed. In other cases, roofs have been lost completely with solar panels still attached!

More likely is damage caused by flying debris. However, this type of damage is usually confined to relatively small geographic area and random.

The great news is that solar panels as a structural attachment to your residence are almost invariably covered under insurance policies. If you suffer a loss that exceeds your deductible, your panels can be replaced as part of your claim.

While you may be concerned about hurricanes in Southwest Florida, we have many, many operational systems installed that weathered many storms over the past decades. I just visited a home with a solar pool heating installation from 1984 that had all original panels. It was not installed to current codes, and it still handled Hurricanes Charley and Wilma among several other glancing blows by big storms.

1984 Solar Pool Heater
Ian Morrissey inspects an operational 1984 solar pool heater that was installed by Fafco Solar over 18 years ago!

 

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