The new hospital will have three types of storm-hardened windows. Lobbies and other public areas that can be evacuated quickly will have windows with a rating for 110 mph winds, stronger than the typical 90 mph rating for commercial buildings. Mercy is adding a film of plastic laminate to prevent the glass from shattering. Patient rooms will have laminated glass designed to withstand winds of 140 mph. For the intensive care unit, technicians in Minnesota are developing windows that will withstand impact from a 15-pound, 2x4 wooden missiles at 100 mph, which replicates debris flying in a 250-mph tornado.
"There is a field-applied safety laminate [that] will stand up a lot better than normal glass," Farnen says. "It will keep the glass from breaking up into shards and flying all over so that if the glass does give, the whole piece will pop out and it doesn't become a weapon or projectiles flying through the air."
When tornado warnings are issued, hospital staff will move patients and visitors into the interior.
"Every floor of this hospital will have a center core area where the ceilings will be reinforced and the interior walls will be reinforced and the end of the core area will have metal storm doors," Farnen says. "Everybody who can be moved will be moved into the center core area. The patients that can't move, that is where we have the 250 mph graded glass and we will defend those in place."