In February of 2015, CPP Principal Dr. David Banks, P.E., an expert on how solar panels behave in the wind, co-hosted a webinar with Ron LaPlante, S.E., chair of the Solar Photovoltaic Systems Committee of the Structural Engineers Association of California (SEAOC). Wind Design for Solar Photovoltaic Arrays highlighted the challenges and recommended solutions for designing solar arrays that meet widely accepted wind loading criteria. The webinar was co-sponsored by the SEAOC and S.K. Ghosh Associates, Inc., a seismic and building code consulting firm with offices in Orange County and the Chicago area.

Solar panel installations, bolstered by federal and state tax credits and incentives, have witnessed widespread adoption by utilities and private investors alike over the past two decades. Just in May 2018, California made history by becoming the first state to require every new home built to have solar panel installations, which will surely increase residential solar power. But like countless other technological innovations, deployment technologies have far outpaced the regulatory framework required to ensure safety.

Nowhere has this disconnect been more apparent than when a local permitting official, tasked with signing off on a proposed PV layout, realizes that the provisions in such standards as Minimum Design Loads for Buildings and Other Structures, ASCE/SEI 7-10, offer no guidance in how to accurately estimate critical wind loads. Structural engineers have used local building codes as best they can, but the process has been a classic example of the square peg and round hole dilemma.

But this situation is changing. SEAOC, working closely with Dr. Banks, has developed guidelines in Report SEAOC PV2-2012 for roof-mounted PV, many of which are expected to be adopted in ASCE 7-16. The webinar detailed the provisions of this report and addressed valuable information for those who design, approve, and install photovoltaic installations. Topics included:

• Recommendations in Report SEAOC PV2-2012 regarding wind loads for sloped PV arrays on flat roofs, and their adoption into ASCE 7-16.
• Implications and issues when applying ASCE 7-10 wind design methods to ground-mounted PV arrays.
• Acceptable test methods to generalize wind loads when using the ASCE 7 wind tunnel procedure for the design of PV arrays.
• New provisions in the 2015 IBC (International Building Code) related to wind loads on PV arrays.
• A practical numerical example of a tilted array on a flat roof
• Three question-and-answer periods.

If photovoltaics are integral to your business, use design methods that are expected to become part of the building code. For more information, please contact us.

Originally published: February 1, 2015