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RE: Oklahoma Schools unpreparedness?

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Enhanced tornado protection areas have been formally designed for probably 
2 decades.  An EF 5 tornado CAN produce winds that could exceed the 
capacity of a ETPA, but tornados are ranked for the maximum velocity which 
is very inconsistent as it moves along the ground.  An EF 5 is very rare, 
but if you have no ETPA, you have no chance.  There were survivors in the 
building that consisted of partially grouted masonry walls with only a 
dropped cieling.  I discussed the nature of tornadic winds many years ago 
with Dr. Fujita in Chicago.

I could cite the 100's of schools that have been hit, and reconstructed 
with no ETPA.  ETPA's are not that expensive.  You take the bathrooms and 
provide solid grouted walls with a concrete roof and an indirect entry.  My 
 uncle built one for his resort in 1959 in Branson, MO.  It provided 
comfort for his guests even though in about 50 years of service his resort 
was not hit by a tornado of any size.

It is interesting to do the probabilistic survey of an EF 2 or greater for 
a building in tornado alley.  The odds are very long.  But if you look at a 
 county, the odds shorten.  A tornado does not cover a very large area. 
But if it is YOUR area, you are concerned.  It is just not worth the worry 
to NOT have a school or public building without an ETPA.

Regards, Harold Sprague

> From: sgordin(--nospam--at)
> Date: Thu, 23 May 2013 20:13:48 -0700
> Subject: Re: [SEAINT-SEAOSC] Oklahoma Schools unpreparedness?
> To: seaint-seaosc(--nospam--at)
> Bill,
> Are you saying that nothing can be done?
> Does not seem quite so...
> V. Steve Gordin SE
> On May 23, 2013, at 5:41 PM, Bill Polhemus <bill(--nospam--at)> wrote:
>> You do understand what direct hit by an EF-5 tornado would do to any
>> structure you can name above ground, right?
>> W. L. Polhemus, Jr. P.E.
>> 4

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