Goedjn wrote:
On Wed, 18 Oct 2006 15:53:03 GMT, John~

wrote:

In article , Bret Miller
wrote:

.....
I also am searching the web for some info, ...

You can start at
http://www.fema.gov/txt/plan/prevent...ter_bkgrdr.txt
....

You are aware, are you not, that a simple concrete-filled
block wall won't stop a tornado launched 2x4? ...

Where did you get that? Hollow block, no; filled, yes...

"The following are examples of wall and
door materials that passed the debris impact test
(further information is available on the Texas
Tech University website at
http://www.wind.ttu.edu/inshelter/inshelte.asp):

* 6-inch to 12-inch concrete masonry unit
walls, with vertical and horizontal reinforcement
and all cells poured full with 3,000-psi concrete..."