Page 66 - Security Today, January/February 2021

"Aside from the specific code requirements for a safe room, an important place to start for any specifier or decision maker is to learn about the many aspects of designing for wind load."
Across the nation, educational facilities are being designed with not only edu- cation in mind – but to ensure stu- dents, faculty and staff are protected during extreme weather events. The inclusion of storm shelters, safe rooms and best available refuge areas are steadily increas- ing, especially due to recent code changes in the heart of the United States. By specifying commercial rolling doors and shutters that meet strict wind load and flying projectile requirements, classroom pods, cafeterias and gymnasiums can maintain a welcoming appeal while able to transform into a safe space within seconds.
While the science is clear behind the life- saving abilities of these spaces, storm shelters and safe rooms are not common nationwide. This is due to cost and the perceived lack of need in areas outside of “Tornado Alley.” But as the threat of extreme weather continues to grow, including in states that rarely saw torna- does and extreme weather events in the past, there are more reasons than ever for school districts to create life-saving spaces in schools.
That is why it is increasingly important for facility managers, school administrators and architects to better understand how building for safety — including specific storm shelter and safe room code requirements — can save lives and protect communities.
Understanding Wind Load and Rolling Doors
Aside from the specific code requirements for a safe room, an important place to start for any specifier or decision maker is to learn about the many aspects of designing for wind load. The term “wind load” is used to refer to any pressures or forces that wind exerts on a build- ing or structure. There are three types of wind forces that can be exerted on a building, includ- ing uplift, shear and lateral wind load — all common in a tornado, hurricane or strong thunderstorm with straight line winds.
Uplift wind load is an upwards force of wind that affects roof structures or similar horizon- tal structures in a building, such as canopies or awnings. Shear wind load is a horizontal pres- sure or force that can cause walls or vertical structural elements to shift or crack, causing a building to tilt. And lateral wind load is anoth- er horizontal wind pressure that can make a structure move off its foundations or overturn.
All three of these forces contribute to cal- culating structural wind loads, but wind shear has a major effect on the performance of roll- ing doors. Unlike static wind load, shear wind load can change wildly based on weather con- ditions. Extreme weather, such as hurricanes, tornadoes and thunderstorms with straight line winds, put extreme forces on a building and can lead to doors blowing out due to wild swings in positive and negative pressure.
Even “regular” gusts of wind due to sur- rounding topography and common weather patterns can affect the performance of a rolling door as well as the building envelope. That’s why rolling door and shutter products are tested for both static and operable wind load. Static wind load specifies the maximum wind load at which a door is able to remain safely in place while closed. Operable wind load speci- fies the maximum wind load at which a par- ticular door is able to safely operate.
Although one can use a simple formula to calculate wind loads from wind speed, it’s not best practice. Architects, designers and engineers should incorporate many addi- tional factors into wind load calculations to ensure structures won't blow over during high winds. This is particularly important in areas of the country where high wind speeds dictate special design considerations.
“It’s vital for specifiers and decision mak- ers to reach out to manufacturers to learn more about wind load requirements, and options for rolling doors and counter shut- ters,” said Siva Davuluri, vice president, mar-
keting, CornellCookson. “Our architectural specialists and consultants use a Door & Access Systems Manufacturers Association (DASMA) calculator to identify comprehen- sive wind load needs and create custom clo- sure solutions,” he added. “Plus, they can work with the designer, architect or facility manager to ensure they are making the best decision when it comes to safety.”
How Does This Apply to Schools?
As extreme weather continues to wreak havoc throughout the United States, school districts have a fundamental responsibility to keep occupants safe. This includes installing rolling doors and shutters in safe rooms, storm shelters and areas of best refuge to provide protection against strong winds and flying debris. But this responsibility goes far beyond ethical considerations.
Many school districts are not even aware that the current International Building Code (IBC) requires all educational facilities with more than 50 occupants to provide a safe room to protect students and staff from torna- does and other extreme weather events in cer- tain areas of the country. This requirement, which first appeared more than a decade ago, applies to any new construction, retrofit addi- tion, or significant improvement projects. The 2015 and 2018 IBC updates include the same requirement, and it is expected to remain in future releases of the IBC.
In states or localities that have adopted IBC 2015 or newer and are in an area that has an increased risk of tornadoes (identified as the
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