Based on the BC Building Code 1998 I found the following
for your question. Remember the acutal jurisdiction may
have a different requirement:
The BC code and National Building Code of Canada do not
use wind velocity. They use a design velocity pressure
in kPa based on recurrence frequencies of 1 in 10yrs, 1
in 30yrs, and 1 in 100yrs. The value you seek is the 1
in 30yr value.
>From Appendix C 1998 BCBC, the values for Vancouver,
including Richmond, Surrey and W. Vancouver are as
1 in 10 : 0.36 kPa = 7.72 psf
1 in 30 : 0.44 kPa = 9.19 psf
You could convert these to mph via p=0.00256*V^2.
Like all codes the design pressure is modified by
several factors to account for terrain, gusting and
height above the ground.
The design wind speeds in US codes are based on
approximately a 1 in 50yr occurance and are based on
fastest mile velocity for 3 seconds at 30 feet in height.
the B.C. Code formulae is: p=q*Ce*Cg*Cp where:
q= design velocity pressure
Ce= exposure factor
Cg= gust factor
Cp= pressure coefficient
I will stop now and suggest you get a copy of the B.C.
Building Code or Xerox the sections you need at the
library and call the jurisdiction your are in for actual
Hank Lonberg, P.E.,S.E.
> Can anybody tell me where to find wind speed info for VE7 or, more
> particularly, Vancouver? I may be wrong but I don't believe that I can
> simply use the value for Seattle. In any event, from a legal point of
> view I think it would be hard to defend decisions based on wind data
> from a different country than the one I live in.
> TIA for your help de Jim Smith VE7FO
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