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[TowerTalk] Opinions on U.S. Towers Tubulars

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Subject: [TowerTalk] Opinions on U.S. Towers Tubulars
From: (JC Smith) (JC Smith)
Date: Wed, 28 May 1997 11:29:49 GMT
Hi Steve, you wrote:

>     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. 

That 50 mph is going to have to change.  The 1991 UBC used tables based on a 50
mph wind speed, but the new 1994 UBC used tables based on 70 mph winds.  I just
ran into that with my newest tower.  The calcs I got with the tower were
supposed to be done to the new UBC, but the engineer "skimped" a bit (used some
of the old data to keep from having to do it all over again) and was caught by
the county engineer.  They had to redo their calcs completely.  Now they are to
the new UBC standards and I got the permit.  I would think this would all be
the same whether the tower is crank up or not.  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?

An interesting side note is that up until just a few months ago permits were
being granted based on calcs using the old (1991) UBC tables.  I'm not sure
what happened to change that.  Perhaps someone finally did their job and
discovered that the tower mfgr. was "cheating" (saying UBC 1994 on the cover
sheet but using UBC 1991 data inside).
>       So you wind up having to present engineering data for a down-rated
>tower and come up with a wet PE stamp as well. Sometimes local building
>departments will accept the manufacturer's drawings, but most times they

Maybe this is different with some manufacturers.  In my limited experience the
manufacturer's drawings and the calcs are one and the same.  The manufacturer
pays a PE to do the drawings and calcs for them (or to go over the drawings
they did in house) and then hands out copies with their towers.  Are you saying
some building departments require "custom calcs" be done for every
installation?  Mine did need an original signature, but not much else (other
than the afore mentioned corrections).  But again, why would this be any
different for a crankup?
>      Building permit requirements are a lot different than the kind of
>zoning conditions that you enumerated. Once you conform to the zoning, then
>you can apply for your permit. The PRB-1 and other visible tower fights have
>more to do with zoning and restrictions than with building permit matters.

Out here they go hand in hand.  First you get your plans stamped by the
"communtiy development department" (planning, they check zoning, setbacks,
etc.), then you get blessed by the sanitary district (to ensure you are not
building on an easement) and then you get your plans checked by the engineers &
plan checkers who issue the permit.  Some municipalities even have "one stop
shopping" where you can go to one place to do it all.  But it would still be
the same no matter what kind of tower you wanted to put up.  Around here I
suspect if any type of tower was going to be more of a problem to get approved
than another it would be the guyed tower that would be the most hassle.  Out in
the rural areas it probably doesn't matter.

73 - JC,

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