A storm shelter is an underground or above ground bunker designed to protect the occupants from extreme weather, particularly tornadoes. Storm shelters are used where tornadoes are frequent, and a low water table permits underground structures. Areas of Texas with low water tables and no flooding would be suitable for a “TornadoShield” storm shelter.
Storm shelters are built close enough to a house or employment building to allow instant access in an emergency, but not so close that the building could tumble on the door during a storm, trapping the occupants inside. This is the reason that the main door on most underground shelters is angled rather than parallel with the ground. An angled door allows debris to blow up and over the door, or for sand to slide off, without blocking it. The angle reduces the force necessary to open the door if rubble has piled on top.
Storm shelters must be designed, built, tested, and installed properly to meet any of the US FEMA-320, FEMA-361, ICC-500, NPCTS (National Performance Criteria for Tornado Shelters), or ICC/NSSA Standards.