Saferooms are hardened structures specifically designed to meet the Federal Emergency Management Agency (FEMA) criteria and provide “near-absolute protection” in extreme weather events, including tornadoes and hurricanes.  In a typical resident installation the saferooms are anchored to the garage concrete slab or a concrete slab outside of the home.
What is a safe room

Accordingly “FEMA strongly encourages homeowners and communities to build safe rooms, but cannot endorse or approve specific manufacturers or producers.” Saferooms manufactured by Valley Storm Shelters™ are among the strongest on the market. Each saferoom uses 1/4 inch steel plate (10.2 lbs per square foot) and 4” C- channel (5.4 lbs per linear foot) to construct our shelter. The C-channel is welded to quarter inch plate on 24” centers on all four sides and roof. The floor is made of ¼ inch thick steel.