F.E.M.A. DESIGN REQUIREMENTS
FOR IN-GROUND TORNADO SHELTERS
Based on Criteria Listed in Federal Emergency Management Agency publication
FEMA 320 /August 2008;
ICC 500-2008 ICC/NSSA Standard For The Design and Construction of Storm Shelters;
ASTM E 1886-05 Standard Test Method for Protective Systems Impacted by Missiles
NPCTS -National Performance Criteria for Tornado Shelters
ALL STORM SHELTER MODELS MEET
OR EXCEED THE REQUIREMENTS LISTED BELOW
ICC 500 Sect 502.2
Access Opening — Requires access opening minimum size 24″ wide x 30″ long.
All STORM SHELTERS exceed requirement
ICC 500 Sect 502.3.1
Vertical Access — Requires minimum tread depth 8″ and maximum riser height 9-9/16″
All STORM SHELTERS exceed requirement
ICC 500 Sect 502.3.1
Vertical Access — Requires minimum Stair width 22″ and slip resistant surface.
All STORM SHELTERS exceed requirement
ICC 500 Sect 502.3.1
Overhead Clearance — Requires minimum overhead clearance 6′-8″ or 5′-0″ with signage.
All STORM SHELTERS exceed requirement
ICC 500 Sect 502.3.1.2
Handrail required on stairways having more than three stairs.
All All STORM SHELTERS have a continuous handrail on one side of stairway.
ICC 500 Sect 502.4
Occupant Density — Requires minimum 3 sq ft usable shelter area per occupant.
All STORM SHELTERS exceed requirement.
FEMA 320 & 361
NPCTS
Requires minimum 3 hinge attachment points and 3 positive latch points.
All STORM SHELTERS have full length hinge with 3 point lock system
NPCTS
Requires exterior key accessibility for post storm Emergency Entry by EMS personnel if needed when latches are engaged from the inside.
All STORM SHELTERS exceed requirement. Emergency access can be made by removal of full length hinge from outside with 2- 7/16” wrenches.
ICC 500 Sect 302303/304
Loads and load combinations, Hydrostatic loads, wind loads, required for the construction of shelters
All STORM SHELTERS have been tested by a third party engineering firm for underground structural design. All models exceed the requirements.
Windborne Debris Hazards — Requires tornado shelters exposed surfaces to be designed tested to emulate wind speeds of 250 mph. 15-lb sawn lumber 2×4 missiles impacting exposed surfaces less than 30 degrees from horizontal at 67 mph and exposed vertical surfaces at 100 mph.
DESIGN TESTED AND PASSED TESTING AT T.T.U. WIND ENGINEERING FACILITY DATA AVAILABLE UPON REQUEST
ICC 500 Sect 702.1
Requires 2 sq. in. or 4 sq. in. of natural ventilation based on location of ventilation ports per occupant.
All STORM SHELTERS manufactured to meet or exceed ventilation requirements.
