[TowerTalk] wind loading

[K7LXC@aol.com]

In a message dated 04/06/2000 9:32:42 PM Pacific Daylight Time, 
alwilliams@olywa.net writes:

> My local area regulations require meeting 80 mph winds.  Is there a simple
>  derating factor for ratings for 70mph to 80mph?

      Here's a chart of wind speed/pressures:

WIND SPEED PRESSURES

Wind pressure           Mean velocity
(Pounds per Square Foot)        (Miles Per Hour)

10.0 PSF            50 MPH

14.4  PSF           60 MPH

20.0  PSF           70.7 MPH

30.0 PSF            86.6 MPH

40.0 PSF            100 MPH

50.0 PSF            111.8 MPH

60.0 PSF            122.5 MPH

      You can see that going from 70 to 80 results in an increase of almost 
50% wind pressure - a big increase.

Cheers,   Steve    K7LXC
Tower Tech 

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