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[TowerTalk] Opinions on U.S. Towers Tubulars

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Subject: [TowerTalk] Opinions on U.S. Towers Tubulars
From: (Stan Griffiths)
Date: Sat, 31 May 1997 17:18:13 -0700 (PDT)
>>     Since you asked, most times obtaining a building permit entails having
>>stamped PE drawings in your document package.
>That's the way it is around here.
>> Crank-ups are mostly rated at 50 MPH
>>where the minimum TIA-222 wind speed is 70 MPH. UBC and other building
>>codes are generally in the same ballpark. Also, the crank-up drawings are
>>only PE stamped in their state of manufacture; you need a local PE to stamp
>>your local drawings. 

  In our county it doesn't
>matter, you still need the signed calcs no matter what kind of tower.  Also I
>would think that since PEs are licensed by the states, and many states do not
>accept work from out-of-state PEs that this would be the same problem, no
>matter what kind of tower you are putting up.  It would be out here.  Am I
>missing something?

The thing that is different about crankups is that they are the ONLY type of
tower I have ever seen advertised or speced for windspeeds of only 50 MPH.
I think the reason is obvious:  If you really speced them for the winds they
will actually experience, they are too weak to hold up much of an antenna
with any safety factor at all.  If the manufacturers speced them
conservatively, they wouldn't sell any of them.


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