Re: [TowerTalk] Calculations

["Alan C. Zack" <k7acz@cox.net>]

OK, I agree with what you said.  But why can't a major manufacturer 
like UST provide these calcs when required and smaller guys like 
Tashjian Towers and Heights Towers can?

Jim Lux wrote:
> Probably because most building departments don't require IBC-2000 yet. Codes
> get revised every few years, but municipalities don't have to adopt them,
> and sometimes prefer to stay with the older code, since everyone is used to
> it.  For instance, Thousand Oaks, where I live, uses the California Building
> code, 2001 Edition, which is based on UBC97.  I would assume that most of
> California is the same. One should also bear in mind that folks doing a LOT
> of construction, or who have significant development plans might agitate for
> a change in codes in a locality to make their life easier. Since you're in
> the Las Vegas area, where there's a lot of new residential development, and
> some pretty significant resort/hotel development as well, maybe one of the
> developers likes the particular provisions of the other code, for what
> they're spending their millions of dollars on, and is willing to convince
> the city to go along.
>
> It would probably cost a fair amount for the mfr (several thousand $,
> perhaps) to update all the calculations, etc., and unless a majority of
> their customers want it, they're not going to invest the dollars.  How many
> towers does the mfr sell in a year? How many of a particular model (because
> the calculations are model specific)?  Say they sell one tower of a given
> type a week (50 a year) at $2000 a crack, retail.  They actually only
> probably get $1500 or so wholesale for the tower, so they're making around
> $150 profit on each one.   Call it $7500 total profit on that model for a
> year.  Say it takes an engineer a week to do all the calculations. That's
> about $3000-$4000 (by the time you count the benefits, burden, taxes, etc.).
> It's just not worth it for the company to blow half their profit margin on a
> set of calculations that a small fraction of the customers need.  They'll
> figure that those folks who really need it will fork out the bucks needed to
> persuade their local building department.  As far as the retailer being able
> to get data where you can't, I would think it unlikely.  If the mfr has it,
> they'll supply it. If they don't, the retailer's probably not going to do
> any better than you, unless they can convince the mfr that they've got
> customers lined up to buy towers, if only the mfr had the calcs.
>
> So, in summary, it's just the economics of the situation.  When it comes to
> building regulations, hams are an anomaly, with little incentive on
> anybody's part to make life easier (at least not for free).
>
> Jim, W6RMK
>
>
> ----- Original Message -----
> From: "Alan C. Zack" <k7acz@cox.net>
> To: <WarrenWolff@aol.com>; <towertalk@contesting.com>
> Sent: Monday, September 13, 2004 7:53 PM
> Subject: Re: [TowerTalk] Calculations
>
>
>
> > And why does a major tower manufacturer stick to outdated UBC-97 50
> > and 70 MPH wind calcs rather than the newer IBC-2000 specs.  UST did
> > send me a nice set of drawings based on UBC-97 that my Bldg Dept said
> > were great IF they were based on IBC-2000 instead.  I suppose some
> > hams will order and install the towers without a Bldg Permit or some
> > Bldg Depts still accept the UBC-97 specs, but why can't they provide
> > what the Bldg Dept requires?
> > Even my local AES store tried to get the IBC-2000 specs for me and
> > were also unsuccessful.

--
__________________________________________________________________________ 

Alan Zack
Amateur Radio Station K7ACZ
Las Vegas, Nevada, USA
Quality Engineer, The Boeing Company, Retired
Aviation Chief Warrant Officer, U.S. Coast Guard, Retired
U.S. Coast Guard, Always Ready, Always There
Every hour, Every day, Around the Clock and Around the World
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http://gocoastguard.com


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