Volume 46, Issue 6 - July 2011

feature

 

How to Make A Hurricane-Resistant Building
Hurricane-Resistant Glazing Suppliers Take Note of Potential Code, Product Changes
by Megan Headley

The Atlantic basin is expected to see an above-normal hurricane season this year, according to the seasonal outlook issued by the National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Center.

Across the entire Atlantic Basin for the six-month season, which runs June 1 through November 30, NOAA is predicting 12 to 18 named storms, of which 6 to 10 could become hurricanes (winds of 74 mph or higher), including 3 to 6 major hurricanes with winds of 111 mph or higher. Each of these ranges has a 70-percent likelihood, and indicates that activity will exceed the seasonal average of 11 named storms, six hurricanes and two major hurricanes.

Bill Enderle, senior estimator and director of preconstruction for Key Glass in Bradenton, Fla., isn’t expecting business to come knocking as a result of the dour forecast. “Business is really dictated by other things … because the forecast is generally
wrong,” he says.

Point taken.


“Last year the forecast was off—but you never know,” adds Fred Gebauer, business development manager with Insulgard Security Products in Brunswick, Ohio.

Right or wrong, the dubious forecast hardly seems to matter when it comes to demand for hurricane-resistant glazing products during this time of year.

“I have noticed a complacency in Florida, which is typical when some time has passed since a major storm has actually made landfall,” says Rick De La Guardia, president of DLG Engineering in South Miami, Fla. “The above-normal predictions have been such for several years now without any landfall in Florida so I believe this has actually contributed to the complacency. I do not think that the predictions will cause any additional demand more than the typical spike at the beginning of hurricane season.”

“As soon as one comes by or hits us, you may see a slight increase,” says Patrick Smith with Saf-Glas in West Palm Beach, Fla. “Sorry to say, the economy has affected too many people. I don’t see many people in a hurry to change out hurricane windows.”

However, small changes to the codes might lead to demand for these products in new areas (see “Hurricane Codes and Standards,” at the end of this page).

Safe Glass Rooms
Some manufacturers are seeing legislation on the local level that is leading to additional use of hurricane-resistant products.

“Alabama just last year had legislation pass that every new construction school has to have a safe room. Obviously they don’t want to have some separate safe room where you only use it if there’s a storm. What they want to do is try to incorporate that safe room into a part of the building that’s being used every day,” says Gerry Sagerman, sales development for Insulgard Security Products. “In order to have a classroom that you can use everyday you’ve got to have natural light in there. So they’re faced with how to have windows in those classrooms but then when a [storm] hits can use it as a shelter. That’s where we come along.”

Sagerman notes that for buildings to be used as safe rooms or for use by emergency responders, FEMA offers grants for construction, so long as all FEMA-tested products are used and requirements are met.

As one example, Sagerman recalls his company’s recently completed work on the Gulfport, Miss., police station. “It’s a three-story building and the whole building is literally not even a half mile off the coast,” he says. “When Hurricane Katrina came through, the storm surge came in I think 10 feet high in that area. So what they tried to do was create the police headquarters so that it was an emergency responders’ facility—so that building meets the FEMA testing requirements. It has been built to withstand that hurricane when it comes through and will stay a working facility.”

He adds, “Any type of window or door in that building obviously all has to be tested and meet the structural pressure that a hurricane creates, as well as the impact testing and then the cycling after that.”

Glass in a safe room is not such an unusual request today.

“The architects are continually pushing the limits,” Sagerman says. “Originally you didn’t have any windows in these units, these almost safe room ‘bunkers,’ and now they’ve started to design with windows. They look for not just punched windows, but storefront. We’ve designed a storefront that would meet the requirements. The next thing they came to us with is ‘okay, that’s great, but do you have an insulating glass that means the requirements?’ So we went and tested and we came up with a glazing that was insulating as well that was tested and met the requirements. It’s a process of continuing to push and to get as creative as you can and still meet the requirements of FEMA.”

More and more today, “layered performance requirements” is the new definition of “pushing the limits.”

More-Than-Hurricane Windows
John Blewis, general manager of Florida Glass & Aluminum Inc. in Fort Myers, Fla., would say that it’s usually not until after disaster has struck that business and homeowners take interest in hurricane-resistant products. “A lot of people don’t want to do it during hurricane season,” Blewis says.

But there are lots of new hurricane-resistant products on the market—and lots of reason to install them.

Michael Stremmel, P.E., senior project engineer for Architectural Testing Inc. in York, Pa., points out that the option to “install products above and beyond what is required in the building code” is “quite common for high value properties, like resort hotels in Orlando.”

Smith says, “Many are using [impact-resistant windows] for security reasons.” He explains, “Some people building to resell only want the least expensive option. Those buying to keep, upgrade a bit for safety and insurance reasons.”

Enderle finds Floridians are showing more concern these days with energy performance than hurricane resistance. “We’re doing more insulating low-E to meet energy codes,” he says. “Most of our buildings now have come out with energy performance calculations—that’s what they have to meet—and it’s even in excess of what’s required by the [Florida Building] Code. We’re doing a lot of premium tint glass and low-E glass.”

He adds, “We are now seeing more private work, and even private work is looking for better energy performance because they’re trying to gain LEED certification.”

“We hardly see a project today that doesn’t have an energy requirement,” Gebauer agrees. “[Designers] are looking at the U-value and what we can do to keep the heat out or the cold out, depending on the season … Not just these applications but when we’re doing bomb-resistant or bullet-resistant the energy performance has become very important.”

Smith notes that this growing interest is just the reason the company’s newest hurricane-resistant glass product—Energy Glass—also generates electricity.

In areas prone to hurricanes, a number of products are promoted to support the glass in its mission to resist debris’ impact and high winds.

“I am beginning to see new products utilizing screens as protection with enough separation from the windows/glass to prevent damage from wind and debris,” De La Guardia says. “In the past, these products were being marketed here in Florida but were not approved for use in the high velocity hurricane zone, nor had obtained product approval from Miami-Dade County. That is now changing.”

Window film companies long have promoted their product as an aftermarket way of improving a building’s safety performance, although glass companies remain skeptical of the performance.

“Films don’t give you a component tested unit,” Smith says. “It’s only a false safety.”

“Safety films as impact protection are very popular as an aftermarket product but the industry has yet to find a way to get these approved by the government agencies since they have to be tested in each specific product that would be utilizing them,” De La Guardia says. “Furthermore, the film would have to be integrated with the frames to perform satisfactorily under cyclic forces during a storm, which is not cost-effective to the consumer or manufacturer.”

Keeping Buildings Dry
Blewis notes that he is seeing a trend, away from dry-glazed products that have been used in these types of installations in recent years.

“A lot of people are getting away from the dry-glazed set down here because they’ve had a lot of problems with it, so they continue to use the wet glaze,” Blewis says. “They [manufacturers] make it sound great but when you actually install it it’s not so great,” he adds.

While Key Glass never adopted dry-glaze, the company has noticed that structural sealing in general seems to have improved in recent years.

“Waterproofing has taken major leaps and bounds in the last five years,” Enderle says.

He explains that the company’s products are tested to higher-than-required design pressures to keep buildings safe and dry.

“By nature of that, they’re pretty well sealed up, because they won’t let water through, and the surrounding conditions are better prepared with water intrusion preventive measures being taken, so what we’re caulking to is better than what it used to be,” he adds.

“You want to be able to handle this high structure requirement regarding the winds and the impacts, but it still has to perform like a normal window: it can’t leak,” Gebauer comments.

Water intrusion during a storm event has become a growing concern for home and building owners who may be taking it for granted that their high-performing hurricane-resistant windows will stay in the frame during high winds.

“Some building owners are concerned with keeping water out of the building after a debris impact event,” Stremmel says. He adds, however, “At the current time, the building codes, as well as the majority of the standards, are primarily focused on the structural integrity of the building and the fenestration products after a debris impact event rather than keeping water out of the building.”

“In my experience, homeowners are sometimes more concerned with water infiltration than with the structural capacity of the product,” De La Guardia adds. “I have visited condominiums where, in my professional opinion, the products need to be replaced due to structural deficiencies and nothing is done about it but much time and money is spent on waterproofing those structurally deficient products. Entry doors that typically do not provide water infiltration protection through their thresholds are now being designed to resist water intrusion. Canopies and overhangs are being used more prevalently to protect from direct rain and get around the products water infiltration deficiencies.”


Hurricane Glazing
CODES and STANDARDS

Glazing contractors and manufacturers are waiting to see how product requirements will change based upon the publication of the 2012 International Building Code (IBC); the updated code was released in June.

“The rumor is that the Florida Building Code is going to follow the IBC and that the design pressures and the way they figure them are going to change all across the state,” says Bill Enderle, senior estimator and director of preconstruction for Key Glass in Bradenton, Fla. “It will probably make it more stringent, which means that the manufacturers are going to have to look again and it’s going to keep engineers busy.”

Among the changes being incorporated into the updated code is a change to the American Society of Civil Engineers (ASCE) standard 7-10, Minimum Design Loads of Buildings and Other Structures.

Michael Stremmel, P.E., senior project engineer for Architectural Testing Inc. in York, Pa., says, “The method that is used within ASCE 7-10 to determine design pressure was changed when compared to ASCE 7-05.” Stremmel says in the grand scheme this is a small change, but even small change may mean adopting something new. “The end result of this change is minor when comparing the design pressure when calculated with ASCE 7-10 when compared with ASCE 7-05, but there will most certainly be confusion about proper interpretation of the changes,” he says.

Julie Ruth, code consultant for the American Architectural Manufacturers Association, elaborates, “The 2012 IBC will reference the 2010 edition of ASCE 7. These documents will require impact-resistant glass further inland from the East and Gulf Coast than it was previously. The changes will be even more pronounced for buildings of greater significance to life safety, such as hospitals and police and fire stations.” Ruth notes, “AAMA has formed a task group to specifically study the potential ramifications to our industry of this and other provisions of the 2010 edition of ASCE 7.”

Rick De La Guardia, president of DLG Engineering in South Miami, Fla., adds, “ASCE does not directly speak to the strength of glass but rather the wind pressures that it would need to sustain. I have read that ASCE 7-10 is making some radical changes to the make-up of the standard but how this affects the future design wind loads is yet to be determined.”

Alan Carr, S.E., Code and Standards, International Code Council (ICC) in Bellevue, Wash., explains.

“The good news is the technical requirements in the code under protective openings, specifically glazed openings, really haven’t undergone any changes in this cycle. But where there’s sort of a hidden change in there is that the new wind speed maps have been revised based on a new procedure that was promoted in the latest edition of the ASCE 7 load standard. What’s happening is the new IBC will now have, instead of a single wind speed map, three maps. So the map wind speeds that you get varies based on what’s now called the ‘risk category,’ what used to be the occupancy category of the building,” he says.

“How that impacts opening protection is that the definition of wind-borne debris region has been updated to reflect the new mapping wind speed. … By having the different maps based on risk category, a wind contour that defines the wind-borne debris location might be in a different location from where it was previously, particularly if you’re in the highest risk category—‘essential facilities,’” Carr continues.

Carr aims to put manufacturers and installers at ease by adding, “There could be some confusion surrounding this in the sense that the [ASTM standard for missile tests] was written for the old wind measure and hasn’t been updated to the new wind speed measure, but the IBC contains a section under the opening protection section that says ‘when you’re using the ASTM E standard for missile impact you have to reword it so you use these wind speeds.’ And ASCE 7 has a user note that says ‘the wind zones that are specified in ASTM E1996 for use in determining the appropriate missile size for the impact test have to be adjusted for use with the wind speeds of ASCE 7-10 and the corresponding wind-borne debris regions.’ Then it refers you to the commentary to see what the adjustments need to be.”

As De La Guardia points out, most affected parties will have some time to review the changes as the updated requirements would not be mandatory until the 2012 IBC is adopted by specific states or localities. States are not required to adopt the latest version of the IBC; in fact, 21 states at present have adopted the 2009 IBC statewide, according to information from the ICC. Missouri and Nebraska still use the 2000 edition.

Ruth adds, “Although our industry typically would not expect to see these changes taking place for another year or so, the state of Florida appears to be moving ahead with them more quickly than that.”

With tornadoes much in the news of late (see “Standing Up to Tornadoes” page 30), Fred Gebauer, business development manager with Insulgard Security Products in Brunswick, Ohio, notes that for many areas, FEMA 361-2008, Design and Construction Guidance for Community Safe Rooms, is the standard to pay attention to. As he explains, “The original FEMA 2000 basically was [focused on] tornadoes and now they’ve brought in the hurricane and the tornado requirements all under the same FEMA specification.” He adds, “What they learned from Katrina, as an example, is that while it was a hurricane it had tornadoes embedded in the hurricane.”

 


Megan Headley is the editor of USGlass.


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