Taking Shelter From the Storm: Building a Safe Room For Your Home or Small Business
"Having a safe room in your home or small business can help provide "near-absolute protection" for you and your family or your employees from injury or death caused by the dangerous forces of extreme winds. Near-absolute protection means that, based on our current knowledge of tornadoes and hurricanes, there is a very high probability that the occupants of a safe room built according to this guidance will avoid injury or death. A safe room can also relieve some of the anxiety created by the threat of an incoming tornado or hurricane. Our knowledge of tornadoes and hurricanes and their effects is based on substantial meteorological records as well as extensive investigation of damage to buildings from extreme winds. All information contained in this publication is applicable to safe rooms for use in homes as well as in small businesses..."

Also available as a cd-rom product:
HS 5.120:Sh 4/2008/CD
Taking Shelter from the Storm: building a Safe Room for Your Home or Small Business., 3rd edition.
U.S. Department of Homeland Security, August 2008