Sign engineering keeps up with code compliance

File photo

File photo

By Louis Cortina
The next iteration of the International Building Code (IBC), which includes safety-related guidelines for structural sign design, has been slated for release in 2015. The last update was in 2012.

While signs in Canada are governed by other codes, restrictions, zoning and regulations, including the country’s own building codes, IBC’s rules affect many signs built in Canada and shipped to the U.S.

The first IBC was published in 2000, bringing together three previously separate documents: the Standard Building Code (SBC), the Building Officials Code Administrators International (BOCA) National Building Code (NBC) and the Uniform Building Code (UBC). Since then, it has been updated every three years.

While some jurisdictions delay enforcing current codes, the majority are now following IBC with regard to signs. Specifically, Chapters 16 to 23 cover the structural design of signs, including minimum loads acting on buildings and other structures with reference to wind speeds. These ratios are key, as a small rise in wind speed will greatly increase the pressure on a sign.

IBC also references guidelines published every five years by the American Society of Civil Engineering (ASCE) that relate to sign structures and load combinations, i.e. which forces need to be applied at the same time and in which ratios. So, the current guideline is the 2010 version and, like IBC, a new edition will be released in 2015.

ASCE has changed its wind speed maps and their corresponding importance factors. For the majority of jurisdictions, the allowable wind speed for signs was changed from 145 to 185 km/h (90 to 115 mph). There are notable exceptions, however, such as the wind speed along Florida’s southeast coast, which was changed from 233 to 298 km/h (145 to 185 mph).

When jurisdictions change their local codes, the changes are usually unlikely to affect the design of signs, but it is always important to be sure. Signmakers should consult with a structural engineer who is familiar with sign design to determine a given project’s loading and structural requirements. There are many other factors in calculating the load on a sign, which an engineer will also take into consideration.

Louis Cortina is president of Michael Brady, an architectural and engineering services firm. For more information, visit www.michaelbradyinc.com.

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