Page 67 - Security Today, January/February 2021
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250-mph wind zone), educational facilities are also subject to ICC-500 standards. This inter- national code provides the minimum require- ments to safeguard public health, safety, and general welfare relative to the design, con- struction, and installation of storm shelters constructed for protection from high winds associated with tornadoes and hurricanes.
At a base level, a safe room in these facilities must protect against high winds and flying objects. How high and how much of an impact depends on if the safe room is designed to withstand a tornado or a hurricane. Tornadoes involve short, violent wind bursts, pressures, and impacts. Hurricanes typically come on slower, last longer, and can deliver sustained wind and flooding. So top hurricane design wind speeds are 235 mph, while top tornado design wind speeds are 250 mph.
Impact speeds are similarly different — more intense for tornadoes, and less so for hurricanes. As such, hurricane shelters have impact test criteria of being able to withstand a 110 mph impact with a 9 lb. 2x4 projectile. Tornado shelters must be able to withstand a 100 mph impact with a 15 lb. 2x4 projectile.
It’s difficult to picture the difference between impact ratings, because different tests use different projectile weights, speeds, etc. Doors on normal Florida buildings would have to withstand (with a less than 3 inch permanent dent) a 16 lb bowling ball dropping from a two-story building. A door that is rated for a tornado safe room needs to be able to withstand that same 16 lb. bowling
ball dropping from a 32-story building.
But there are additional considerations to make when it comes to specifying rolling doors in areas prone to extreme weather. This includes states that fall within the Fed- eral Emergency Management Agency (FEMA) 250-mph wind speed zone for tor- nadoes, areas of Florida that are covered by Miami-Dade wind load requirements, and other regional codes and requirements areas. “We introduced an entirely new product a few years ago to combat natural disasters,” Davuluri said. “This advanced rolling steel door is designed specifically for safe room protection against life-threatening tornadoes and hurricanes and is one of few rolling door products tested and certified to meet ICC-
500 and FEMA P-361 standards.”
Davuluri went on to explain that a single
maximum protection rolling door can be used to cover multiple openings, or even banks of windows to maximize natural light — because of this, typical safe room spaces such as cafe- terias, classroom pods and gymnasiums can be open and airy instead of dark and claustro- phobic — helping designers create positive, learning-focused spaces that can also trans- form into safe rooms when needed.
When a storm is nearing and the tornado siren goes off, the rolling door can automati- cally deploy, turning an open space into an ICC-500/FEMA P-361 rated safe room to pro- tect occupants from harsh winds and deadly projectiles. After the storm, the door coils back into the structure until it is needed again.
“Rolling doors like these are best used in spaces with multiple points of ingress and egress because they provide maximum pro- tection at all openings,” Davuluri said. “They also have added psychological benefits, by covering windows and eliminating the chance that students can see a tornado barrel
down on a school–something that tornado- rated glass doesn’t do.”
These same products can be used for a best available refuge area. This refers to an area in an existing building that has been deemed by a registered design professional as likely to protect building occupants during an extreme wind event better than other areas in the building when a safe room is not available.
In addition to maximum protection roll- ing doors for best available refuge areas, manufacturers sell operational wind load doors as well as several other rolling door options. These allow specifiers to protect building occupants and contents in the event of extreme weather. However, it should be noted that they do not meet FEMA-361 and ICC-500 standards.
“New operable wind-rated products are designed with special wind locks which allow the door to seamlessly glide through the guides when exposed to a wind load of 20 psf (referred to as “operable windload rat- ing”) – which equates to roughly 88 miles per hour,” Davuluri said. “These doors are designed for facilities that must be accessed regardless of weather, including fire stations, hospitals, military facilities and airports, but are also helpful when installed in best avail- able refuge areas in schools.”
Wind load doors aren’t the only products that can help protect occupants. Companies manufacture a variety of other rolling doors and counter shutters that address static and operable wind load requirements. These include rolling service doors, insulated doors, fire doors, insulated fire doors and counter doors.
Heather Bender is the strategic marketing manager at CornellCookson.
By Heather Bender
Preparing for
Extreme Weather
What You Need to Know to Design the Safest School Storm Shelters

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