On Sep 20, 11:48*am, "Eisboch" wrote:
wrote in message

...

While a structure is designed using specific wind data, in Florida's
case, the FBC basically the IBC with amendments, and the IBC uses ASCE
7-05 which most building codes use, and those wind maps are based on
100 year data. BUT a structure isn't "rated" by anyone, unless a
private entity, say the builder, decides to do so to make a selling
point. Here is why. Let's say we have a wind of a certain speed and a
certain direction blowing on a rectangular building. Even though the
speed is constant (here's where we show Harry and JimH don't know
****~!) the wind PRESSURE is NOT constant. Have you ever seen a mobile
home on the side of the highway where part of the siding has blown off
when towing? Notice where the siding fails nine out of ten times. The
rear corner. Negative pressure from the wind coming around that corner
has sucked the siding off! In short, the windward wall has a postive
pressure of X amount, the leeward wall has a negative pressure of Y
amount, they are hardly ever the same value. Then you have the roof.
Slope, wind direction, area, etc. all have an affect on the PRESSURE.
In short, we are really designing for this negative and positive
pressure as opposed to wind speed. We simply use data in the form of
wind speed to mathematically arrive at those pressures. And it goes
further, terrain makes a big impact, as well as nearby structure.

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Thanks for the explanation. *It makes sense. * Apparently to us laypeople,
they simply tell us it has to be designed for *XXX amount of wind speed..

Eisboch

You're a smart guy, I knew I could explain it to you and you'd
understand, with an open mind, instead of acting like you know all and
everyone else is an dumbfoch!