Can Metal Wall Systems Be Engineered to 140 Mile per Hour Winds?

Yes. And no. There are many things that could potentially change that answer, for example:

• 140mph in the middle of a populated city center does not have the same effect as 140mph on an open lake or water surface.
• 140mph on flat ground does not have the same effect as 140 mph located on the side of a mountain.
• A wall panel fastened with supports at 1’ on center might withstand 140mph, but the same panel with supports at 5’ on center may not.

There’s no magic to 140 mph. In some areas like South Florida and USVI, we are frequently asked to engineer wall projects to 180 mph and can successfully do so.

How Are Windspeeds Determined/Engineered

In the United States, the entity that publishes the nationwide standard on wind design (for buildings) is ASCE, the American Society of Civil Engineers. The standard that is used is titled: ASCE 7. This book is updated once every 4-6 years on average, with the most current version as of this writing being the 2022 version, commonly called ASCE 7-22. This book is created using research from respected authorities in the industry (predominantly university-based research).

This research is frequently done for wind loads with weather station-type data and wind tunnel research.

Wind speed and the resulting wind pressure can vary based on numerous factors:

• Rough terrain (forests, buildings, etc) tends to ‘slow down’ the wind and therefore lowers wind pressures. Smooth terrain does not and therefore increases wind pressures.
• Flat topography tends to have a neutral effect on wind pressures, whereas steep hills or plateaus speed upwind, therefore increasing wind pressures.
• The elevation of the project affects the pressures; projects closer to sea level increase wind pressure.

The most important factor affecting wind pressure is the shape of the building itself. Gable roofs have different wind pressures than monoslope roofs, hip roofs have different wind pressures than curved roofs. Buildings with no walls at all have different pressures than buildings with walls.

Avoid Dangerous Assumptions

So, for some customers with the right applications and the right product choices, absolutely, the system will withstand 140-180 mph winds. But for other customers, the product may very well NOT be able to withstand those extreme wind speeds.

Therefore, many engineers avoid stating absolute wind speeds because it can create problems downstream

Next Steps

Assume nothing; realize building location, geometry, and size carry implications.

If you’re looking for specific structural performance, work with a registered engineer who is familiar with the specific products you’re using and have the following info readily available:

• Local building code
• Building purpose/occupants (used to determine the factor of safety code)
• Contact your manufacturer’s technical department - they should be able to help - but you will be expected to provide a lot of technical information about your project, the location, the support system, etc.