# Wind Load Code Requirements



## fj80 (Jan 18, 2017)

I'm designing a single family residence in Tennessee, an area I'm not familiar with, and the builder has asked me to check for any wind load code issues. We're using IRC 2012.

I've looked at Figure R301.2(4)A, B, and C and that area is not within any of the shaded areas for required wind design. Is that the only thing I need to look for, or are there any other parts of the code that pertain to wind?


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## CityKin (Jan 18, 2017)

Look at the lines on the map.  If for example you are between the 90 and the 100 lines, then you design for 90mph. I don't have the 2012 code right in front of me but by looking at the 2009 version, it looks like you will need to design for 90mph 3 second gust of wind.


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## Francis Vineyard (Jan 18, 2017)

See R301.2.1 "Wind speeds for localities in special wind regions, near mountainous terrain, and near gorges shall be based on elevation. Areas at 4,000 feet in elevation or higher shall use 110 V mph (48.4 m/s) and areas under 4,000 feet in elevation shall use 90 V mph (39.6 m/s). Gorge areas shall be based on the highest recorded speed per locality or in accordance with local jurisdiction requirements determined in accordance with Section 26.5.1 of ASCE 7."

It's on the eastern border in map R301.2(4)B


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## Francis Vineyard (Jan 18, 2017)




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## fj80 (Jan 18, 2017)

There are no special wind regions anywhere in Tennessee on Figure R301.2(4)B, and 90mph winds. The gray area near there appears to be in North Carolina and Virginia. So does this mean wind design is not required?


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## JBI (Jan 18, 2017)

Lacking some local history of unusual wind conditions (or possibly a local amendment to the IRC), it would appear that 'wind design' is not automatically required.


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## fj80 (Jan 18, 2017)

JBI said:


> Lacking some local history of unusual wind conditions (or possibly a local amendment to the IRC), it would appear that 'wind design' is not automatically required.


Ok, thanks. That what I am thinking too. I have a call in to the local building department to ask for their local climatic and geographical design criteria from Table R301.2(1). I think that should be everything I need.


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