Windstorm Solutions for Hurricanes and Tornadoes

Various codes apply when preparing for the forces of nature

• By Minu Youngkin
• Sep 01, 2014

Adverts Every year, the country braces for Mother Nature and the havoc she unleashes with major windstorms. At one time, only coastal states like Florida seemed to be affected. In recent years, however, the destruction has veered beyond Florida, requiring many states to seek shelter from the storm. Consider this:

• From 2010-2012, there were more than 3,900 tornadoes, resulting in 667 deaths in the United States.
• Between 2010 and 2011, 31 hurricanes or tropical storms caused more than 387 deaths and more than $33 billion in damages.
• Nearly every state is at risk for tornadoes or hurricanes.

It All Starts with Code

When it comes to windstorm solutions, it’s all code-driven as door, lock and hardware chosen for an opening are determined by hurricane or tornado codes. The challenge comes with knowing which codes apply.

“Windstorm solutions can be tricky because codes can vary by state, and even county,” said Lori Greene, manager of codes and resources at Allegion. “With hurricanes, for example, the old Southern Building Code (SBC) was the first code to include hurricane-resistance requirements in building construction design, and Miami-Dade County was the first state entity to enforce compliance of this code. However, these requirements and testing protocols to address the state of Florida have since been incorporated into the Florida Building Code.”

Additional requirements may apply to certain types of buildings for enhanced hurricane protection.

“Schools and hospitals, for example, may have additional hurricane code requirements in certain regions,” said Steven King, a specification writer with Allegion.

While most buildings in coastal states are subject to windstorm codes for hurricane protection, it’s a different story in tornado regions, namely the center of the United States.

“The current national codes are not specific about which facilities are required to have storm shelters,” Greene said.

Changes have been approved for the 2015 edition of the International Building Code that will require storm shelters in educational occupancies and emergency operations facilities in certain parts of the country. Green said that these new requirements will be adopted on a state-by-state basis, so it’s important to check with your state to know what is required. However, regardless of whether your state adopts them, Green advocates compliance with the new requirements because they reflect best practices nationwide.

The main codes and standards that apply to windstorm solutions are shown in Table 1.

Types of Buildings and Applications

In hurricane regions, many types of buildings are required to have windstorm solutions, including—but not limited to—schools, healthcare facilities, commercial buildings, retail locations and community storm shelters.

In tornado regions, typically schools and community shelters are subject to windstorm shelter requirements. Shelters, however, may be built in a variety of buildings.

According to Casey Cohorst, CSI, CDT, LEED GA, a specification consultant with Allegion, the type of application may also drive the final solution. “Like any other door solution, windstorm solutions have unique requirements based on the application,” Cohorst said. “What is done for an exterior door may be different than a door for a classroom wing or gymnasium used as a shelter. What you need may vary by building, or even door by door.”

Integrating Access Control

Openings equipped with windstorm solutions can still have access control. However, because of the unique windstorm assembly, there are special considerations.

“We can definitely provide access control for a hurricane or tornado door, and there are a couple ways to do that,” King said. “Because an electric strike can’t be used on these openings, we generally recommend an electronic lock.”

Electrifying a Von Duprin panic device is another way to add access control to an opening.

Proven to Perform

The last consideration for choosing a windstorm solution is performance testing. Allegion simulates wind speed and potential projectile impact to measure how its products hold up—individually and as an assembly, which includes doors, frames, locks and hinges.

For hurricanes, Allegion products are tested to resist windborne debris impact loads and cyclic, static wind pressures as prescribed by the Florida Building Code. With tornadoes, these products are tested to the most stringent FEMA 361/FEMA 320/ICC 500 requirements, withstanding 250 mph sustained winds and 15-lb projectile impacts at 100 mph.

This article originally appeared in the September 2014 issue of Security Today.