U.S. Department of Energy Energy Efficiency and Renewable Energy

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April 15, 2013
Q.

Are there any solar panels that have passed hurricane impact or bomb blast tests? -Tony

SunShot Solar Outreach Partnership

The SunShot Solar Outreach Partnership has been tasked with helping accelerate adoption of photovoltaic (PV) solar at the local level by providing timely and actionable information to local governments.

A.

Your question is an important one, as many consumers and businesses may wish to reduce greenhouse gas emissions through solar energy, even as these pollutants drive climate change and threaten to increase the frequency and intensity of hurricanes and other severe weather events.

Solar panels are built to withstand the toughest elements like powerful winds from hurricanes, hail, and torrential downpours. Many panel manufacturers design their products to withstand wind loads of about 2400 pascals (Pa), or about 50 pounds per square foot (psf). Examples are available here, here, and here. However, some modules are designed to withstand even greater loads. Unfortunately, it is difficult to translate these ratings into an across-the-board maximum wind speed rating. Doing so requires a site-specific calculation that takes into consideration factors such as solar array orientation, system height, surrounding topography, and local wind conditions. An in-depth examination of how photovoltaic (PV) wind loads are calculated can be found in this guide published by the Solar America Board for Codes and Standards (SolarABCS).

Roof-mounted solar panels depend heavily on the strength of the roof to tolerate extreme impacts. Just as the roof of your home has to abide by strict state building codes, so does anything that is attached to the roof, like solar panels. These building codes list certain requirements for wind loads; meaning that the solar panels on your home must be installed to cope with specific amounts of wind. The American Society of Civil Engineers (ASCE) and its “Minimum Design Loads for Buildings and Other Structures” (Standard 7-05) provides standards for both wind and snow loading, along with many other factors, which can be applied to the design and installation of solar PV systems.

Some solar modules are also tested to gauge their resistance to hail strikes. ASTM International has developed methods to test module resistance to hail, and the International Electrotechnical Commission (IEC) has developed hail-related performance standards. According to the international testing service TÜV SÜD, most modules tested are able to withstand an impact from a 1-inch hailstone traveling at about 50 miles per hour. 

To our knowledge, no standards or tests currently exist to ensure a solar module’s resistance to bomb blasts.

Should you like to learn more about residential solar and solar energy technology, visit the Small Solar Electric Systems page on the Department of Energy’s website.

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