I've seen, first hand, in Oklahoma, the damage a F-4 tornado can do. In a tornado of that class the only place safe is underground in an anchored shelter. Large tornado's have been known to suck, shallow buried, storage tanks out of the ground. An F-4 tornado can lift a railroad locomotive and toss it just like a car. I'm sure an APC will protect people from flying debris but a near miss or direct hit is going to be bad news.
We had a F4 in 1995 June 2 and it lifted and moved two trains & locomotives. Loaded boxcars went through the cemetery cutting off trees, stones, anything in it's path throwing the cars around. Rail was twisted and rolled around looked one of those giant roller coaster rails in the sky was sticking up 60 ft or so in the air rolled around sticking through more boxcars one twisted pile of scrap metal !
The next thing to consider is debris on the egress/access opening after an event. That's why some tools would be expedient. But largely, as long as it is an official record with First Responders they would know how to locate the shelter and get any occupants to safety within a reasonable period of time after it was safe to do so.
Plus, in many of those cases, you would want more than one to provide for all those present in the facility and especially to have one close to different areas of a large campus. Thus, the chances are not all of them would be blocked.
I'll look up the author and publisher when I get home tonight. That should help in locating a copy. Like I said, depending upon one's viewpoint of the bomb scenarios people may have a difficult time with some of it. BUT, they definitely bring out all the other purposes for such protection and provide much information.
Have a Great Day, Brent
Found it:
'Fighting Chance: Ten Feet to Survival' [Arthur Robinson, Gary North] on ...Publication Date: June 1, 1986 | ISBN-10: 0930462106 | ISBN-13: 978-0930462109
Available at Amazon and others.
Have a Great Day, Brent
One more time:
These guys make quite a case for spending money to protect our children and how little money would be involved to do this even with no other construction going on at the time. Areas in storm alleys, fire zones, and cities with high bomb probabilities should really consider this move.
Just my two tin pennies worth. All part of why I really like the area I live in...not near a big city, not in the jet stream path from a big city, not in normal storm area (though Flagstaff has had tornadoes only 60 miles as the crow flies from us), not a military target, etc.
But, still need to have your resources and be prepared.
Have a Great Day, Brent