Volume 6, Issue 4, July - August 2002
The Eye of the Storm
Industry Bewares as Hurricane Season Approaches South
by Steve Sabac
Statistically, we’re in trouble. Every June 1 marks the beginning of hurricane season. With that, everyone in the coastal Eastern United States and Gulf states watches and wonders—will this be the year another “Andrew” hits? This year, though, may be much more worrisome. The United States has never gone three years without a hurricane strike. In 2000 and 2001 there were no land falling hurricanes. Statistics don’t lie.
Florida’s New State-Wide Building Code
On March 1, 2002, the entire state of Florida adopted a new windborne debris hurricane code. This code is modeled after the very stringent Dade County Code in effect in South Florida since Hurricane Andrew hit in 1992. Finally, the entire state of Florida and many other states have begun to wake up and take notice. Hurricane mitigation is crucial. We need codes in effect that will help ensure that storms will not wipe out entire cities and infrastructures.
After Hurricane Andrew, teams of engineers visited South Florida to determine what made structures fail and what caused such major damage. Building envelope seal failure was prevalent everywhere. Windborne debris caused glass to break. When the glass breaks, a building is no longer “sealed” and begins to pressurize internally. Under intense wind loads, this can lead to roof lift.
Three testing protocols were designed to test windows to withstand these massive hurricane forces. First, a window must be struck multiple times by either small missile criteria or large missile criteria. Then that same window must be pressurized 9,000 times. The pressure gradually increased to 4,500 cycles and then begins to decrease. This is to simulate the stages of a hurricane (for example, an approaching storm [winds build], overhead [winds peak], and then passes [winds change direction and then subside]).
Lastly, the window is pressurized and hit with water spraying out of jets to simulate wind-driven rain. Not a drop of water is allowed to pass through the window.
In the end, the window truly looks like it has been through a war. As if this is not enough, for the window system to be listed as an “approved means of hurricane protection” by an independent approval agency, all three of three windows must pass all the protocols together.
Window Film and Hurricane Codes
Does any window film by itself carry a hurricane approval rating? The answer is no. Film by itself is an outstanding way to keep broken glass together and strengthen glass against the force of an impact. But window film is just one component of the entire system of approved protection. The film acts like a water-resistant membrane. To complete the system and seal the opening, this membrane must be attached adequately to the existing window frame. If the filmed glass panel is not anchored to the frame properly, the entire panel would most likely fall out of the opening during the impact testing. If not, the simulated wind-cycle testing would push it right out of the frame, which causes failure.
Anchored Film Systems
The only window films rated as an approved means of hurricane protection today are anchored film systems. Proper anchoring of the filmed glass panel to the existing window frame is critical. This is the most crucial area of concern when window film is deemed “hurricane-approved protection.”
There are anchored window film systems that have made it through all the rigors of the testing protocols and are listed as an “approved” means of hurricane protection.
Anchoring the film to the frame may not be the end of the securement process. During a pre-inspection of a major banking headquarters, Jason Kromolicki, M.E., for WindowLock® discovered that the existing window frames were not anchored to the building sufficiently. If these window frames were not secured properly, the whole window set-up, including the film system, could be dislodged from the building. This would happen because once the film and glass are anchored to the window frame the load is transferred to the windows anchoring to the building. He solved this by reanchoring each frame to the building with masonry screws during the installation of the film anchoring system.
Anchored Window Film
Built prior to the South Florida hurricane codes, the Kravis Center for the Performing Arts in West Palm Beach, Fla., was a disaster waiting to happen. With massive expanses of searing glass walls, the installation of typical hurricane protection, such as plywood shutters, was out of the question. It would take a small army of personnel with ahead start of many weeks just to accomplish this. Replacing all the glass with hurricane-approved laminated glass was not cost-effective.
The Kravis Center chose WindowLock® anchored film system for the project. WindowLock® incorporates Madico’s clear window film with in its anchoring system. The center’s installation was the ultimate challenge because of its beautiful high lobby windows. When completed, the protection system was nearly invisible. From the beginning, the original architect of the Kravis was extremely concerned and rigid about not changing the famous profile of the center.
Sun Coast Glass Protection provided the Kravis Center for the Performing Arts with an invisible attachment system to protect it from hurricane damage.
Anchored Film System as Hurricane Protection
Deviation from the original installation method of the film anchoring system that is tested and approved should be avoided. If after installing window film, a customer sees his electric bill decrease by 23 percent instead of the 25 percent anticipated, it most likely will not be scrutinized.
However, if the product a customer purchased to protect against hurricanes fails and the failure is due to corners being cut on the anchoring system, this could lead to a major liability. For example, structural adhesive is being used as an anchoring system by itself. If structural adhesive was applied in a large amount around the edge of the frame to pass testing and that is how it was tested and approved, then that is exactly how it should be installed in the field.
The structural adhesive is a bridge connecting the film and the frame. The bead, bite and throat thickness of the structural adhesive is absolutely critical in the performance of the film anchoring system as tested and approved. Engineered cross-section drawings sealed by a professional engineer and accepted by an approval agency such as Factory Mutual (FM) or Southern Building Code Congress International (SBCCI) should be studied closely and supplied to customers so they can verify the installation. The time may soon come when all types of hurricane protection will be put to the ultimate test. Let’s make sure window film reflects not only heat but professionalism as well.
Steve Sabac is the owner of Sun Coast Glass Protection Inc., the manufacturer of WindowLock®, in Boynton Beach, Fla.
© Copyright 2002 Key Communications Inc. All rights reserved. No reproduction of any type without expressed written permission.