When ASCE7 is not enough, where do you turn? The code covers most typical building and non-building structures, but practicing engineers know there is always that odd job or new trends that aren’t always picked up by the code in a timely manner. Unless you own your own wind tunnel laboratory, it can be difficult to accurately predict wind loads on multiple roof top structures, or tall parapets or solar arrays. But perhaps ASCE7 isn’t the only solution for determining wind loads on non-building structures.
In November 2019, Emily Guglielmo, SE, from Martin/Martin presented Wind Loads on Non-Building Structures for SE University. Emily recognized that there are non-building structures and building components that are not expressly addressed in ASCE7. In those instances, the practicing engineer should seek guidance from other resources, and Emily was able to recommend several guides that may be helpful.
Emily referenced the SEAOC Technical Report PV2-2017 Wind Design for Solar Arrays. This guide is available for free download for members or for a $20 fee for non-members. The solar industry has moved much faster than structural standards are able to adapt, thus, SEAOC developed additional research-based guidelines, since the initial inclusion of PV2-2012, and issued this report which will be reflected in future editions of ASCE7. Engineers can use this guide to design arrays with tilted panels on low sloped roofs, flush mounted arrays on sloped roofs, and ground mounted solar arrays. However, it does not yet address roof mounted systems with tilted panels that are not low profile or arrays on other roof shapes. Further guidance is included in the Wind Design Manual developed by SEAOC which includes 7 design examples on solar PV systems. This manual can be purchased through ICC for $95 with ICC and SEAOC members receiving a discount.
Emily also recommended ASCE’s Wind Loads for Petrochemical and Other Industrial Facilities. This guide could prove useful for determining wind loads on various exterior yard-type structures, including duct work, trellised elements, pipe racks, vessels and tanks. For engineers that spend time designing lattice-type structures or steel antenna towers, the new version of the ANSI/TIA-222-G is a great resource. Emily suggested using ANSI/NAAMM FP-1001-97, 4th Edition to assist with wind calculations on flagpoles and flag loading. Another useful guide includes the IBHS Research Center’s Wind Loads on Small Roof-Mounted Air-Conditioning Units. This guide is available for free download and offers research on the effects of venting, elevation, and the location of the units on the roof.
While ASCE7 does not specifically address every non-building structure, these additional resources can help fill in the gap with wind provisions developed by other industries and researchers.