In response to the escalating frequency and intensity of windstorms across the United States, the installation of storm shelters on educational campuses emerges as a critical component of ensuring safety for students and staff.
Storm shelters are pivotal in providing a secure refuge during extreme weather events as they are designed to protect occupants from the high winds and flying debris that often occur during tornadoes and hurricanes. The International Building Code (IBC) defines a storm shelter as a building or structure constructed under ICC 500, Standard for the Design and Construction of Storm Shelters, and designated for use during severe windstorm events.
Given the unpredictable nature of tornadoes, which often strike with minimal warning, having designated storm shelters on educational campuses can significantly reduce safety risks in severe weather emergencies.
Necessity Based on Weather Patterns
The IBC mandates storm shelters in regions where severe weather conditions pose a significant threat, such as areas with wind speeds of 250 mph as determined by the American Society of Civil Engineers (ASCE). This requirement applies across 23 states and may span the whole state or a portion of the state. Minnesota, Louisiana, Texas, and New York are examples of states that define the edges of the affected area and highlight the geographic scope of vulnerability.
As climate patterns shift and windstorm activity potentially increases in unexpected areas, the need for robust storm shelter infrastructure becomes apparent. Beginning with the 2015 edition, the IBC includes requirements for storm shelters in two types of buildings: educational occupancies and critical emergency operations centers including 911 call stations, as well as fire, rescue, ambulance, and police stations.
IBC Requirements for Storm Shelters in Schools
Under the IBC, storm shelters are mandatory for Group E educational occupancies with a calculated occupant load of 50 or more occupants. The 2015 IBC mandates storm shelters in educational facilities to accommodate the total Group E occupancy load. Following this, the subsequent editions specify that shelters must accommodate the greater of either: a) the total load of classrooms, vocational rooms, and offices or b) the load of any associated indoor assembly space.
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According to the recent editions of the code, if a new building added to existing Group E sites cannot house the required shelter load for all buildings on-site, the existing shelter must meet at least the capacity needed for the new building. Officials may adjust the shelter’s load requirement based on existing shelters, but the shelter must be inside or within 1,000 feet of an exterior door of each building it serves.
A storm shelter can also serve as a multipurpose facility. It may be a building specifically designated as a shelter or an existing building used for other purposes, such as a gymnasium. Even in these cases, the building must still meet the shelter-design requirements of ICC 500.
ICC 500 Storm Shelter Requirements for Schools
When an educational facility meets the IBC storm shelter criteria, ICC 500 requires shelters to meet stringent requirements and undergo rigorous testing, including requisites related to egress, fire protection, and accessibility.
Door assemblies are subjected to large pressure loads and multiple impacts at speeds of 100 mph to verify that the door can withstand severe windstorm conditions by remaining closed and latched. Upon completion of this test, the approval must be listed with a third-party agency and labeled as complying with the performance requirements of ICC 500.
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ICC 500 designates that hardware securing these doors must automatically engage when closed or be capable of engagement by a building occupant, be permanently mounted, and be operable without tools. The 2014 edition of ICC 500 addresses weather exposure and requires a maximum undercut of ¾-inch with a weather seal at the bottom of the door. This version also addresses requirements for anchorage and inspections and specifies the minimum and maximum door sizes that must be tested.
In addition to the criteria above, the 2020 edition of ICC 500 includes changes to egress, fire protection, and accessibility requirements, among other factors. To stay informed on updates, it’s important to consult the newest editions of the applicable codes and standards.
Egress, Fire Protection, and Accessibility of School Storm Shelters
The number of egress doors required for a storm shelter depends on its occupant load, calculated by dividing the shelter’s area by the occupant load factor in the building code. If the space is solely a shelter, ICC 500 provides a table for occupant load calculation. Doors serving more than 50 occupants must swing in the direction of egress. If one door is sufficient for the load, an additional emergency escape opening is needed, unless the load is less than 16 occupants. Egress doors for educational spaces with 50 or more occupants must ensure that latching hardware is panic hardware and complies with applicable standards.
ICC 500’s fire barrier requirements call for partitions with a two-hour fire-resistance rating and 90-minute opening protectives. In compliance with NFPA 80, Standard for Fire Doors and Other Opening Protectives, fire door assemblies must include positive-latching hardware, suitable hinges, gasketing, and other listed/labeled components.
One important consideration is that if the fire rating is only required for compliance with ICC 500 and is not required by the adopted building code, ICC 500 does not require the door to be self-closing or automatic-closing. The intent is that the doors will be closed manually and will provide the required protection when they are in the closed position.
Accessibility standards are also paramount, ensuring all occupants, including those with disabilities, can safely access and utilize shelter facilities. Per ICC A117.1, Accessible and Usable Buildings and Facilities, shelters must have accessible routes with clear opening sizes and compliant operation without tight grasping, pinching, or twisting of the wrist.
Other factors must be taken into consideration as well as these regulations and requirements only represent a small portion of the codes required. Consulting with a shelter expert familiar with IBC and ICC regulations and requirements is recommended for proper design.
Future Considerations and Adaptations
As weather patterns shift and tornadoes increasingly impact regions previously deemed less vulnerable, it is crucial to maintain flexibility and adherence to storm shelter design and construction standards. Even educational facilities currently not mandated by the IBC to have storm shelters can proactively consider installing one on campus to mitigate risks from severe weather events. In doing so, building administrators can play a crucial role in campus safety.
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To meet the criteria of a certified storm shelter, compliance with all relevant requirements and codes is imperative. This ensures that the structure not only meets current standards but also undergoes regular inspections, adheres to maintenance protocols, and provides staff training on shelter operations to maintain its effectiveness over time.
As educational institutions refine their emergency preparedness strategies, integrating robust storm shelter solutions will continue to be essential for fostering a safe and secure learning environment.
Lori Greene, DAHC/CDC, FDAI, FDHI is the manager, codes and resources for Allegion. She has worked in the door and hardware industry for more than 35 years and is responsible for support and training on the code requirements related to door openings. She participates in the code development process with the Builders Hardware Manufacturers Association (BHMA).
Note: The views expressed by guest bloggers and contributors are those of the authors and do not necessarily represent the views of, and should not be attributed to, Campus Safety.
