Risk Category IV wind speeds v. tornado wind speeds
Risk Category IV wind speeds v. tornado wind speeds
(OP)
A client is asking us to evaluate the differences in structure due to the wind loads from typical risk category IV wind speeds [120 mph] and an F2 tornado highest value wind speed [157 mph].
I explained that these are two different things (3 second gust and a possibly longer sustained wind speed).
The IBC wind speeds are ultimate the Fujita scale wind speeds are not.
What would be your approach for trying to evaluate this situation?
Is there a way to bring the tornado wind speeds up to an ultimate value or bring the IBC wind speeds to a nominal value?
I at least would be starting from the same level, but still with different types of wind loads.
I explained that these are two different things (3 second gust and a possibly longer sustained wind speed).
The IBC wind speeds are ultimate the Fujita scale wind speeds are not.
What would be your approach for trying to evaluate this situation?
Is there a way to bring the tornado wind speeds up to an ultimate value or bring the IBC wind speeds to a nominal value?
I at least would be starting from the same level, but still with different types of wind loads.






RE: Risk Category IV wind speeds v. tornado wind speeds
RE: Risk Category IV wind speeds v. tornado wind speeds
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RE: Risk Category IV wind speeds v. tornado wind speeds
Check out Eng-Tips Forum's Policies here:
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RE: Risk Category IV wind speeds v. tornado wind speeds
https://www.fema.gov/wall-sections-passed-previous...
RE: Risk Category IV wind speeds v. tornado wind speeds
Wind gusts and tornado winds are different animals and this was explained to the client.
They asked for a study after hearing our explanation.
Do the FEMA documents use the Fujita scale for the wind speeds?
This is strictly a study at this time. The missiles and internal pressures will all be considered if the client opts for a tornado shelter.
RE: Risk Category IV wind speeds v. tornado wind speeds
(FEMA 361 is a free download found Here)
There are, however, various wind speed ranges given in this table from FEMA 361:
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