How Do They Test Storm Shelters?

So, you’ve decided to buy a storm shelter. That’s probably a good choice, since tornadoes can form anywhere given the right conditions. In fact, nearly a third of the United States lies in an area that meteorologists call Tornado Alley.

According to the National Institute of Standards and Technology (NIST), a large portion of the United States falls into Wind Zone IV (see map), where the risk from extreme windstorms (tornadoes) can be up to 250 miles per hour.

In fact, the highest tornado wind speed ever recorded, 312 mph, was in an EF-5 tornado that hit just south of El Reno, OK on Friday, May 31, 2013. At times, this killer twister was over a mile wide.

How can you be sure that the storm shelter you choose will protect your family from such extreme weather? Look for proof of certification.

Safe Rooms vs. Storm Shelters

Manufacturers, government agencies, and standards organizations tend to use the terms safe room, storm shelter, and tornado shelter rather interchangeably.

The term “storm shelter” comes from the International Building Code, whereas the term “safe room” is used by the Federal Emergency Management Agency (FEMA) to mean a structure that meets the following standards:

For our purposes, we’ll use the term “storm shelter” as found in the ICC-500 standard.                                     

How Are Storm Shelters Tested and Certified?

Storm shelters and their components are tested for compliance with the ICC-500 standard. Currently, testing and certification of storm shelters is performed by Intertek and Underwriters Laboratory (UL).

Two kinds of tests are performed to test compliance with the ICC-500 standard:

  • Pressure equal to 1.2 times the maximum rated wind speed is applied to the component being tested.
  • Dynamic impact from windborne debris is simulated by launching a 15 lb. piece of 2×4 lumber from a pneumatic cannon. The speed and number of impact test locations are specified in the standard. (See a pneumatic cannon in action.)

How Can You Tell If a Storm Shelter is Certified?

Certification of shelters and their components is indicated by application of Intertek or UL labels showing the standard used, impact rating, and other test information. You should find these labels on the door, locking mechanism, and wall assemblies.

Make Sure Your Shelter Meets the Standards

Above-ground storm shelters are a relatively recent innovation, and the applicable FEMA and ICC standards have evolved over the last couple of decades.

Storm shelters built to today’s standards will protect you and your family from even the most extreme wind events. Certification provides proof that a shelter has been built (and tested) to comply with those standards.

To be sure, look for the certification label.

— — —

Questions? Want to learn more? Contact us at (417) 680-5118, (800) 781-0112 or

Contact Atlas

Use this form to enter any question.

  • This field is for validation purposes and should be left unchanged.