Storm shelter standards: what to look for

"FEMA approved" gets said a lot. FEMA doesn't approve or certify individual shelters. What matters is whether the shelter was designed and tested to the published criteria below — and whether the installer can show you the paperwork.

The documents

• ICC 500 — the ICC/NSSA Standard for the Design and Construction of Storm Shelters. It's the building-code standard. The City of Springfield lists the 2014 edition among its adopted building codes.
• FEMA P-320 — Taking Shelter from the Storm, FEMA's guide for residential safe rooms, with designs a homeowner or builder can use.
• FEMA P-361 — FEMA's design criteria for safe rooms, used mainly for community and school safe rooms. Its residential criteria line up with P-320.

FEMA's safe room pages have the full documents.

What the standards require, in plain terms

• 250 mph design wind speed. FEMA recommends residential safe rooms be designed for 250 mph winds, the highest safe room design wind speed. Missouri sits inside the 250 mph tornado shelter zone on the ICC 500 map.
• Debris impact. Walls, roof, and door must stop a 15-pound 2x4 board. At the 250 mph design wind speed, FEMA's criteria have it fired horizontally at 100 mph (with a slower vertical test for roofs).
• Tested as an assembly. The door, its frame, hinges, and latches have to pass together, not just the wall panel.
• Anchoring. The shelter must stay put — no sliding, overturning, or lifting — under those loads. For garage units, that depends on the slab and the anchors.
• Space and ventilation. Minimum floor area per occupant and enough ventilation for the people inside.

What to ask an installer for

• The test report or documentation showing the model's walls and door passed ICC 500 / FEMA debris and pressure testing, and who did the testing.
• The anchoring specification and how they'll confirm your slab meets it.
• Whether the shelter carries an NSSA (National Storm Shelter Association) verification or similar third-party listing.
• Who pulls the permit, if one is required where you live. Inside Springfield, start with Building Development Services. Larger and community shelters in the city also require an independent peer review of the design.