valley-storm-shelters-debris-cannon-testingHere is what the National Oceanic and Atmospheric Administration of the Department of Commerce has to say about it:

“There’s no one authority to tell you what the best storm shelter is, nor can the federal government endorse a specific type of storm shelter as being ‘the best.’ However, safety standards for storm shelters and shelter components have been established by the Federal Emergency Management Agency to ensure that you will be protected in most tornadoes, while the National Storm Shelter Association has also established a shelter standard. The Wind Science and Engineering Research Center at Texas Tech University performs tests on shelters and various shelter components to see if they meet both sets of guidelines. Researchers use a high-powered air cannon to shoot wooden two-by-fours at shelter walls and doors to simulate flying debris, while another test uses a wind tunnel to simulate the high winds and stress that walls would encounter. Depending on the type of shelter that’s right for you, these tests and guidelines can help you choose the shelter that can best protect your family when a real tornado hits.”