Volume 50, Issue 6 - June 2015

NewsAnalysis:TORNADO GLAZING

Seeking Shelter: Tornado Glazing Finds Home in Impact Zones

Devastating tornadoes over the past couple years, including the 2013 Moore, Okla., tornado that destroyed two schools and took the lives of seven children, have drawn attention to the need for safe rooms in Tornado Alley and other susceptible regions.

The newly updated International Building Code (IBC) reflects that.

The 2015 IBC adopted the International Code Council’s ICC-500, a standard for the design and construction of storm shelters. The standard mandates storm shelters for schools with 50 or more occupants, as well as for critical facilities—including 911 call stations, fire stations, police stations and emergency operation centers.

The Federal Emergency Management Agency (FEMA) has updated its P-361, Safe Rooms for Tornadoes and Hurricanes safe room guide publication to its 2015 edition.

Gerry Sagerman, business development manager for Insulgard, expects the new IBC will result in increased demand for tornado glazing, though he says he’s already seen an uptick in the application of tornado-rated glazing products.
“There is a continued increase in the number of safe rooms being built, whether it’s for schools, community shelters, and those kinds of things,” he says, noting that it’s also being driven by FEMA’s grant efforts. Cassie Schlosser, president of Protective Structures, agrees, as over the last two years she has seen an increase in grants being awarded to publicly funded schools for safe rooms.

This, coupled with heightened recognition by architects and owners of glazing products that can be tested to standards that show they could withstand or mitigate the effects of tornados, has meant an increased application of tornado glazing.

“You don’t have to be in a dark, steel shelter anymore,” she says.

Safe rooms have very stringent requirements, but they don’t necessarily need to be limited to the gloomy shelter Schlosser describes. Schlosser and Sagerman say that designers and owners are finding ways to designate everyday rooms as safe rooms, and tornado glazing products are helping make it happen.

“Instead of building a room that is going to be used one or two days out of the year, we’re now seeing safe rooms that can be used 365 days a year,” says Sagerman. “We’re seeing [tornado glazing] in classrooms, gymnasiums, even in cafeterias.”

Valerie Block, a senior marketing specialist with Kuraray, plans to give a presentation this month at Glass Performance Days that will show the results of a testing program her company conducted with various glazing constructions using an ionoplast interlayer.


Community Safe Room Costs: Location-Dependent Design Parameter Examples
Wind Hazard ASCE 7-10
Risk Category
ASCE 7-10 Requirements for
Base Building Design Wind Speed/Debris Impact Protection
ICC 500
Design
Wind Speed
Comparison of
Design Wind Speeds (ASCE 7-10 for Base Building VS FEMA Safe Room Design)
Tornado II 115 mph
(e.g., Oklahoma City)
250 mph Significant difference
Tornado III/IV 200 mph
(e.g., South Florida)
200 mph No difference,
though FEMA design
parameters are higher than ASCE 7 requirements
Hurricane III/IV 120 mph
(e.g., New York City)
160 mph Moderate difference
Hurricane III/ IV 200 mph
(e.g., Florida)
225 mph Moderate difference


“From a fabricator’s perspective, laminated glass requires more capital, equipment, materials, labor and skills,” adds Nash. “Customers have a higher cost for laminated glass. It’s the price of gravity for overhead installations.”
Those kinds of challenges are not unique to North America, either.

Gary Aspden, marketing and technical manager at G. James Glass & Aluminum, says the Australia-based glass company made its policy years ago not to install tempered glass on balustrades of high-rise buildings due to the consequence of failure.

With that, the cost concern is one he sees come up as a result.

“Changing to heat-strengthened or [tempered] laminate for use in balustrades is a difficult sell due to the additional cost over monolithic [tempered] glass,” says Aspden. “However, like in North America, we hope changes to our building code will assist this process.”

Ultimately, time will tell how quickly the code changes will affect the demand for laminated glass—if at all. While there has been a lot of talk about the code changes of late, Butler says it hasn’t translated into significantly more purchase orders.

Viracon vice president Rick Voelker says laminated glass volume was virtually the same from 2013 to 2014, and he doesn’t anticipate a significant increase in 2015.

“Having been with Viracon for the past 38 years, the three most significant influences on laminated glass usage were the building code changes in the ‘70s requiring laminated glass overhead in skylights, hurricane impact code requirements and bomb blast applications,” he says. “We thought that laminated glass volumes may also be affected by the FEMA tornado glass design considerations, but as of yet haven’t seen this get legs under it, either.”

—Nick St. Denis



USG
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