To date, there has never been a failure of a FEMA compliant shelter. There have been serious issues with improperly installed shelters.
For example, an insufficient slab or anchors for an above-ground steel safe room that goes in your garage, or new home construction. Improper anchoring of underground shelters. Installing an underground shelter in a flood zone or areas of a high water table.
I saw one picture on social media where a steel shelter was placed on a corner of a sidewalk! The shelter was compliant, but the installation at fault.
Proper installation is key to your survival in a direct hit by severe weather!
It gets very confusing when companies claim they have the best product in the world or the # 1 shelter over all others. Find competent shelter companies who have been in the business with long term A+ standards. Make sure the shelter has been tested and secured by using designated test methods, third party engineering evaluations, stamped engineered paperwork and NSSA (National Storm Shelter Association) or ATSA (American Tornado Shelter Association)certification. You should feel confident in your purchase.
When selecting a shelter look at your options and consider which type best suits your needs. There are FEMA-compliant shelters rated for F5+ in above-ground and below-ground types.
Underground shelters come in many shapes, sizes, and materials. The choices are steel, polymer, fiberglass, and concrete. Alabama’s soil doesn’t freeze, but we get a lot of moisture. Some shelters do better in different geographical areas than others, so consider that.
If your handicapped or just have trouble with stairs, in a flood zone or high water table, on top of rock or sandstone an underground shelter would not be wise.
If you don’t have a garage or house with a sufficient slab, a steel safe room would not work. Steel safe rooms are anchored into the slab. I’m not a believer in putting a steel safe room outside exposed to the weather because of rusting, but some people do.
A walk-in concrete shelter is a good option for someone who can’t manage stairs, don’t have an inside slab, are elderly or just want the convenience of having one close to a home or outbuilding. Typically, they’re set on a gravel pad and anchored to the ground with metal straps and augers, but if you have a slab they can be anchored into the slab. Some people place them into a bank, but concrete below grade can result in moisture issues.
You can also build your own shelter (usually poured or block reinforced with rebar) as long as the person building the shelter sticks to the FEMA plans and includes a FEMA compliant door. The FEMA website has these plans available online.