Stronghold certified storm shelters are compliant to the highest quality standards in the industry, which includes the following: FEMA P-361 2015 and ICC 500/NSSA 2014 and IBC 2015. Installed shelters include the NSSA quality verification seal and NSSA certificate of installation. All shelter models have been debris impact tested at the National Wind Institute (NWI) and verified to withstand winds over 250 mph (EF-5 resistant). Our NWI PASS Letter is on file for customer review. Shelters have also been wind engineered evaluated and documentation is available for customer review.