What is the purpose of "Tornado Resistant Doors and Frames"?
Tornado resistant doors and frames are designed to be resistant to the FEMA
(Federal Emergency Management Authority) 361 standard. This is an American federal standard that has established stringent criteria to resist the wind pressure and possible debris damage caused by tornadoes. Doors and frames that comply with this standard have been tested at independent laboratories.
How do "Tornado Resistant Doors and Frames" differ from "Hurricane Doors and Frames"?
The types of wind pressures that doors and frames are subject to in these two instances
are completely different. Consequently, the standards that govern these products are
distinct. In the case of tornadoes, the units must resist wind loads up to 250 mph
in the outswinging position as well as debris actually shot at the doors at 100 mph.
FEMA 361 is a national standard currently supported by the USA Department of Homeland
Security. In the case of hurricanes, the door/frame units are designed to withstand the
relatively lighter wind loads experienced in a hurricane environment. As well, the
hurricane standards require that door/frame units withstand a minimum level of water
resistance. The Dade County test has been adopted in some coastal areas of the USA.
Currently, national test standards do not exist.
Are there any size or hardware restrictions for "Tornado Resistant Doors and Frames"?
Restrictions with respect to door and frame size as well as hardware configurations conform to
the laboratory prototypes tested by specific firms. Ambico Limited currently has test data to
support the supply of door leafs as large as 4'0" x 8'0" in singles or in pairs. All items
tested require the supply of door hardware actually used in the lab tests and include
heavyweight butt hinges and a multi-point mortise lockset which are factory supplied and
pre-installed.
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