Volume 47, Issue 6 - June 2012
The Joplin, Mo.-based Mercy Hospital garnered national attention following its destruction in May 2011 (see September 2011 USGlass, page 24), images of its tornado-devastated, windowless shell gracing national outlets. When the replacement structure reopened in April 2012, reporters were quick to point out that the windows, supplied by All Weather Architectural Aluminum, were designed with glass ratings that can withstand winds up to 200 miles per hour, exceeding building code requirements.
Since then, the National Oceanic and Atmospheric Administration (NOAA) reported in its State of the Climate report on tornadoes, issued January 2012, that the U.S. spring and summer of 2011 will likely be remembered as one of the most destructive and deadly tornado seasons to ever impact the nation. The Administration explains that during 2012 there were seven individual tornado and severe weather outbreaks with damages exceeding $1 billion, and total damage from the outbreaks exceeding $28 billion. “This represents the most property damage from severe weather in a single year since recordkeeping began in 1980. As of mid-January 2012, the 2011 confirmed tornado count stood at 1,625, with 93 tornado reports still pending for November and December. This places 2011 as the second or third most active year on record for number of tornadoes since the modern record began in 1950, depending on the confirmation rate of the end-of-year tornado reports.”
There were six EF-5 tornadoes confirmed during 2011, and a total of 553 fatalities, the most in the 62-year period of record.
Does that mean building owners and designers are taking a closer look at tornado ratings for windows?
Certainly tornadoes are getting more notice from the codes, though. On April 16, 2002, the International Code Council (ICC) announced that it was extending its support to communities affected by severe weather, including the more than 100 tornadoes in the Plains region, with its Disaster Response Network. The database lists volunteers available to assist with building damage assessment, inspections and other code-related functions. But ICC isn’t yet seeing additional adoption of its ICC 500, Standard for the Design and Construction of Storm Shelters, according to code watchers.
When it comes to windows, few structures in tornado zones are getting the beyond-code protection that has become more common in hurricane zones.
Has Interest Gone with the Wind?
Do these experts expect these requirements in place anytime soon?
“As far as I know, the shelter code, ICC500-08, is only approved in Alabama for schools and in Florida for community shelters,” Condon says. “This code incorporates tornado resistant glazing but is limited to community shelters. ASCE 7-10 and IBC-12 have not introduced any tornado code for non-shelters. Therefore, Risk IV facilities can still be built without impact glazing; even though they are operational during the storm, same as shelters.”
Vinu Abraham, vice president Southeast region for Architectural Testing Inc. in Riviera Beach, Fla., says there’s been a renewed interest in Oklahoma to adopt ICC 500. “… FEMA is taking a more aggressive posture with regard to people who are putting in-residence tornado shelters and are applying to FEMA for grant subsidies,” he says. “We’re seeing FEMA take a stance that those shelters that FEMA is helping pay for, one, have been tested to meet the requirements of ICC 500 and two, have a design professional that will sign off on the installation of the product after the installation is complete.”
“With the widespread devastation that has occurred already this year, many jurisdictions are looking into their local building codes to see if improvements can be made,” adds Ken Brenden, technical services manager for the American Architectural Manufacturers Association (AAMA). However, he points out, “Tornado hazard mitigation is not limited to just the window system. It requires the entire structure to withstand the forces associated with a designed tornadic event.”
Amping Up Design
“I have heard about a couple of hospitals that are interested in hardening their facilities after seeing what happened in Joplin, Mo., last year. I personally think it makes sense for essential facilities to design for this type of potential event if they are in a tornado-prone area,” says Paul Beers, managing member of Glazing Consultants International in West Palm Beach, Fla. “Unfortunately,” he adds of this interest, “usually it blows over.”
Testing labs, however, are seeing more interest in developing tornado-resistant products for the potential niche.
“There are definitely a handful of players who are aggressively developing window products to meet the requirements of ICC 500,” says Abraham. “I know of at least two that have passed [tornado] test requirements successfully. There are several others that are actively trying to develop it. It’s a pretty tough challenge to try to solve.”
The codes aren’t leading the charge; developers of facilities such as schools and community shelters are.
“We haven’t seen any new state mandates but we have seen an increased interest in the FEMA-tested windows for community shelters and safe rooms throughout the Midwest,” says Gerry Sagerman, business development manager for Insulgard Security Products in Brunswick, Ohio. “With the increase in tornadoes and the bad weather and everything going on in the Midwest, we’ve seen an increase in [interest from] a number of schools and community shelters. I don’t know if it’s that the product is getting out there and people are more aware of it, but we definitely have seen an increase in both the hurricane and really the tornado glazing.”
Sagerman adds, “A lot of schools are looking to have safe rooms; Alabama said last year that any new school must have a safe room. I hadn’t seen other states put those kinds of mandates out recently, but whether it’s mandated or not I think the people in charge of the schools, who do construction or renovation, are thinking if we’re putting the money into doing an addition to a school we need to look at adding a safe room.”
Adding Strength Where It Counts
“I think it’s appropriate if you have a hospital or essential facility no matter where it is you should build it to a higher standard, a higher level of quality,” Beers says. However, he notes, “The cost to do that and the will to do that—I’m not sure if it’s out there. But it’s the responsible thing to do.”
Sagerman says his company has seen a couple of hospitals seeking tornado defenses. “I think it’s out there. Obviously the hospital administrators are forced to say ‘do we evacuate the rooms when a storm event comes?’ In some cases, they can’t evacuate the patients, so they’re trying to weigh the cost of doing these windows in these rooms as opposed to trying to evacuate,” he says.
Right now, the more likely scenario involves hardening an interior hallway or room, sans windows. “They won’t have all the windows, but they’ll harden an interior hallway or room in a hospital to try to diminish the cost.”
According to Sagerman, half the battle now is letting designers know they don’t have to include a windowless vault as a defense option. “I think in the past [the design intent] has been to build a concrete vault inside of a school … Now I think they’re saying, ‘Hey, we can use these rooms for other purposes if it had windows in it,’” Sagerman says.
As that knowledge grows, so will the demand for tornado-resistant glazing.
“Definitely you’re seeing it in all types of buildings, from schools to community shelters to hospitals to, really, any place,” Sagerman says. “We’ve even had individuals contact us when they’re looking at putting in a safe room, asking, ‘Are windows available?’”
Confusion Comes Standard
“Our primary business is building bullet- and blast-resistant doors, windows and composite wall panels. We occasionally get inquiries for tornado-rated windows or doors,” says Rick Snelling, vice president and general manager of Armortex in San Antonio, Texas. “There may be some confusion given the similarities between bullet, blast- and tornado- (FEMA) rated windows and doors,” Snelling adds.
Beers hears similar confusion from clients. He recalls hearing from hospital administrators, having watched the events in Joplin, of their interest in learning more about how to prevent such destruction in their own buildings.
“They were saying, ‘We don’t want this to happen to us. What do we do?’ The problem is, even if they want to know to how to do something [to protect their building] they don’t know how to go about it,” he says.
Sagerman adds that confusion on this point is found among design professionals, as well as within the glass industry itself.
“What we still see out there is a real confusion and maybe not an awareness of what the requirements are for some of these windows, and the requirements for testing. From architects to building owners, just not really knowing what all the testing needs to be on these windows and so there’s still a little bit of confusion out there as to what needs to be tested and to be honest there are products that don’t meet all of the requirements of the testing. That’s something we still struggle with as an industry,” he says.
In response to this confusion, AAMA, in collaboration with the National Institute of Building Sciences’ Building Enclosure Technology and Environmental Council (BETEC), published as AAMA 512-11, Voluntary Specifications for Tornado Hazard Mitigating Fenestration Products in 2011. The document provides a system for testing and rating the ability of windows and their anchorage to withstand extreme wind loading, debris impact and water penetration typical of tornadoes. Although AAMA 512 drew from the testing parameters, Protection Levels and geographical wind zones described by ICC 500 and FEMA 361 tornado wind zone charts, it is applicable to the fenestration of any building for which maximum practical tornado protective design is specified.
As the association points out, an EF-4 or EF-5 tornado has the potential to level an entire building, making little difference as to how well its windows perform. However, hazard mitigation opportunities do exist for buildings exposed to the most common tornadoes.
“Prior to the publication of AAMA 512, there wasn’t a voluntary specification that designers and builders could look to for rating and qualifying fenestration products for this type of environment,” Brenden points out. “We fully expect that awareness and the market will increase as more manufacturers expand their product lines to include options for tornado hazard mitigating framing systems.”
Brenden notes that the association has sold several copies of the document and several members are already putting it to use within their own product lines. The expectation is that the document will help promote the manufacture of these products, to some extent.
“The release of AAMA 512 has generated interest in these enhanced products,” says Greg McKenna, PE, of Kawneer Co. Inc. in Norcross, Ga. “Interest has also grown with the increasing frequency of severe weather events. However, since the International Building Code does not specifically address tornados, it [AAMA 512] will remain a standard for niche applications.”
Winds of Change
“We are definitely a lot more interest in people testing products to the tornado standards,” Abraham says. “We’re definitely doing a lot more tornado testing today than we did a year ago.”
Still, it’s all relative when only a handful of players are eyeing this minimal market.
As Condon reiterates, “I do not believe tornado-resistant glazing will advance far until the building code requires it.”
Megan Headley is special projects editor for USGlass magazine. She can be reached at email@example.com.