Volume 47, Issue 8 - August 2012
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Ready and Able?
It’s now been 20 years since Hurricane Andrew struck the Florida coast, leaving widespread damage and a loss of lives across the southern region. Since then, several standards have been released, codes have been updated and tightened, creating a large market for hurricane and impact-resistant products. Ensuring the proper use of hurricane or impact-resistant products can be challenging, however, and there is a lot to learn about this field of glazing. USGlass spoke to several industry experts for this issue about what your company needs to know, challenges you may encounter and more.
The Final Exam
“The first is a test method and the other is a specification for missile impact testing,” says Paul Beers, founder of Glazing Consultants International in West Palm Beach, Fla. “That’s pretty much the universally accepted requirement for hurricane protection for certifying products. All the code jurisdictions use that—the Florida building code, Miami-Dade County, the International Building Code, etc.”
The standards were developed in response to the requirements Miami-Dade County, Fla., created in the 1990s for glazing systems, says Valerie Block, senior marketing specialist for Dupont. “After that, ASTM and members of the industry worked to develop an industry standard, which wouldn’t be Florida-based or Miami-Dade-based. That’s when the ASTM standards were developed,” she says.
In turn, building codes began referencing the ASTM standards (see box at right). “The building code has a preference to refer to industry-based standards,” says Block. “They weren’t looking to reference a standard developed for one specific jurisdiction.”
It’s crucial that manufacturers of hurricane-resistant glazing systems fully understand the codes before delving into this arena, though, according to Dean Lewis, chief engineer of certification programs for the American Architectural Manufacturers Association. “In order to ensure product performance under hurricane conditions, manufacturers should understand the design considerations implied by these codes, and market their design features accordingly [they need] to be clearly understandable by the consumer,” says Lewis.
Block suggests that when manufacturers decide to release a hurricane or impact product, they first must answer a simple question. “The first thing you have to know is whether you’re going for product approval,” she says. “If so, you’d be checking Florida for Florida product approval and Miami-Dade product approval requirements.”
Each area has its own set of criteria to follow, according to Block. “Typically Miami-Dade County requires the impact in pressure cycling, but also calculations that are based around windload and air water leakage,” she says. “Miami-Dade County has a department that basically is charged with review of all the data. Once the Miami-Dade approval department gives you the stamp that you’ve been approved and you become a part of their approved system, it shows you’ve gone through testing.”
Preparation is key. “First you’ve got to develop your product, then you’ve got to confirm that it’s going to be tested in a way that will meet the requirements of the code authorities who are ultimately going to approve it,” says Beers. “The testing itself doesn’t take that long, just a day or two. After the testing’s done you’ve got to submit drawings to whomever you want to get approval from, Florida or Miami-Dade, so the process can take months.”
In addition, collaboration among a variety of parties often is necessary. “There’s a lot of experience and technology now to comply with the standard,” says Beers. “Two things I’d recommend is that [manufacturers] work closely with the test laboratories doing the testing and work closely with the manufacturers that they’re going to be using—particularly those of the glass.”
And that’s a crucial point to remember—that products in these areas are tested as full systems. “It’s not really just about the glass,” says Block. “It’s about the total system and how the total system gets through this testing and evaluation process.”
An Early Start
“Even if you’re well-intended, you’re probably going to need someone to help you get through this,” she adds.
Urmilla Sowell, technical director for the Glass Association of North America (GANA) and president of the Protective Glazing Council, points out that ASTM E 1996 offers three levels of building protection, basic, unprotected and enhanced protection. “Enhanced protection is typically used for essential facilities, [which are] defined in ASTM as ‘buildings and other structures designated as essential facilities, jails and detention facilities, fire, rescue and police stations and emergency vehicle garages, designated emergency shelters, communications centers and other facilities required for emergency response, power-generating stations, other public utility facilities required in an emergency, and buildings and other structures having critical national defense functions.’”
Glazing systems designed for such use are subjected to even more stringent testing than other hurricane products. “Glazing systems designed for enhanced protection are tested using a 9-lb. two-by-four missile with a velocity of 80 feet per second (50 mph), which is higher than the 50 feet per second (34 mph) velocity used to test for basic protection,” she says.
Taking a step back from the system also can be helpful. “It’s always helpful to take a fresh look at your system,” says Block. “ … There’s no automatic guarantee that just because you have a good system that it’s going to be sustainable in [the testing] environment.”
What if you don’t pass? “You may need to make some adjustments to try again,” says Beers.
This doesn’t come without costs, though. “From a budgeting perspective, it would be good for manufacturers to know that they may have to go through some additional expense if they don’t make it through the first time,” says Beers.
Despite challenges, industry experts say the results of today’s testing methods for hurricane products, many of which were developed in response to the damage incurred after Hurricane Andrew, are certainly worth it. “We’ve taken a big step forward in glazing construction,” says Block. “ … After [Hurricane] Wilma, we did a study of 100 different buildings and we were looking to see how they held up, and there was very little damage noted. From the point of view of protecting buildings and protecting people, the requirements for improved glazing or other solutions to prevent against internal pressures building up in a home or building have really improved construction and made construction safer for people.”
Beers agrees. “I think it’s been proven that the standards work well,” he says. “… The purpose of the standards is to protect people and property inside the building and I don’t think anyone would dispute that they’re doing that … It’s good to see how far we’ve come.”
The Codes and Standards
For testing to the Florida Building Codes’s HVHZ areas, the following criteria is used, according to Sowell: large missile with two impacts per glazing; 1/16- by 5-inch maximum opening with no penetration; impact on the mullion or cross bar; and a small missile for all floors 30 feet above grade level.
Following is the criteria used for ASTM E 1886 and 1996: large missile - one impact per glazing in Wind Zone 3 and 2 impacts per glazing in Wind Zone 4; 3-inch sphere cannot freely pass through any opening; no impact of the mullion; and a small missile from 30 to 60 feet.
Sowell says ASTM defines small and large missiles as follows:
Need More Information?
GANA also has available the Laminated Glazing Reference Manual, which “discusses all applications that utilize laminated glazing products, from safety and security to acoustics and energy, in addition to natural and man-made disasters,” says Sowell.
Tornado Testing—One More Step
He adds, “If it’s tested for FEMA requirements, their hope is that after the hurricane or tornado comes through the that safe room hasn’t been impacted or fragmented. They’re looking for complete protection on those types of things.”
In many cases, glazing systems are needed, even for safe rooms, because local officials are placing them in locations such as schools, where they might have other uses as well, according to Sagerman. “Alabama put in legislation that any new school that’s being built has to have a safe room to house kids in tornadoes,” he says. “[But] those schools are looking for rooms that they can use for other uses. They might build a classroom, but in order to have a classroom they have to have windows … and when the tornado comes they can use that room for a safe room.”
Hospitals also are a market for such products. “You saw what happened with that hospital in Joplin, Mo.,” says Sagerman. “[Hospital officials] are really faced with the decision of whether to move patients in intensive care to a safe room, or whether it makes more sense to make the windows in the intensive care unit tornado-resistant.” Testing to offer FEMA products can be quite costly, though, according to Fred Gebauer, business development manager for Insulgard in Grand Rapids, Mich. “Just your samples alone can cost $10,000,” he says. “We do a lot of structural engineering before we even build a sample or test a sample.” www.fema.gov
Penny Stacey is the editor of USGlass magazine. She can be reached at firstname.lastname@example.org. Read her blog at http://penny.usglassmag.com, follow her on Twitter @USGlass, and like USGlass magazine on Facebook to receive the latest updates.