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Let's Talk Hurricane Resistant
By: Donnie Hunter
Hurricane Resistant – Product Development7:15AM on Wed 26 Aug 2009
How do you get building envelope products to meet the market need for hurricane resistance?
Good question! Where do you start: windows, curtain walls or entrances & framing? At first many thought, if it doesn’t open, close or lock it might be possible – or at least it should be easier.
Initial trial and errors:
After some initial R & D testing of standard off-the-shelf products it was clear they would not be able to meet these new impact and cycle requirements. Two common themes became apparent from the R & D testing: (1) these new products must be glazed with some type of laminated glass, and (2) the glass needs to be silicone glazed to the framing system.
Based on this premise, the glazing industry was off and running. The plan was to execute three basic steps: (1) design/modify existing products, (2) test the design, and (3) sell the product. After all, that’s what we do. Unfortunately, early product modification and testing efforts did not go as planned and the problems were numerous: glass failed, silicone failed, and hardware failed.
Small successes set the stage:
We didn’t give up, we continued to plow forward – weeks became months, months became years, and the years continued. Through mostly the dreaded trial and error process we began to make progress, modifying existing systems. The persistence was starting to show results, and even though early product offerings, glazing infill’s and hardware options were limited – they passed the test. The early R & D theories held true, incorporating laminated glass and structural silicone to hold the glass to the system.
A list of common impact resistant glass types can be viewed on the Kawneer web site. Go ->
A shift in approach allows for more product successes:
The shift in approach was key – now products are initially designed and developed with the impact/cycling requirements in mind. A product's ability to handle increased glass thickness is paramount. One of today’s practices is to incorporate the thicker monolithic laminated or insulating laminated glass requirements into a product’s basic design.
With the glass interlayer technology and system design improvements that have been made since the mid to late 1990’s, many of today’s systems can be conventionally glazed using dry gaskets in lieu of the structural silicone approach and still meet the stringent impact and cycling requirements.
Glass and glass interlayer manufacturers like DuPont®, Viracon, SAF-Glass and Saflex® continue to make product improvements.
Today’s offering no longer limited to only a few choices:
Today, product offerings include swing entrance doors, storefront framing systems, curtain wall systems, fixed windows, projected windows, hung windows, and sliding doors. Many of our products offer both the original glazing concept of laminated glass with wet glazing (structural silicone) and the newer glazing concept of laminated glass with dry gaskets.
A complete list of Kawneer impact/cycled tested products can be viewed on our website. Click on the link to see our Notice of Acceptance Documents (NOA) and Florida Product Approval Documents (FL). Go ->
Be sure to let me know about your glass and glazing successes with impact resistant products…
A Look at Testing Standards and Procedures8:30AM on Wed 12 Aug 2009
Hurricanes: it seemed growing up you rarely heard of them, though today we wait with anticipation for the yearly forecast of how many named storms there will be, and how many of those may develop into something more than just a rain storm over the ocean. As we seem to stay glued to the news when there is the possibility of the formation of a new storm, the real question everyone has is when and where will it make land fall? In most cases several scenarios or predicted paths of travel are discussed; however, the storms rarely hit the forecasted target. With hurricane season upon us, now might be a good time to discuss how hurricanes have changed the way we build.
Andrew, a person’s name, why is this important? Because terms like windborne debris, impact, impact resistant, hurricane rated, hurricane resistant, and Miami-Dade NOA became mainstays after Hurricane Andrew hit south Florida in August 1992. Across the region loss of property was huge and lives were turned upside down.
As a result, many within the building industry and local governments decided we couldn’t let such property damage happen again. So the development of impact standards as they are commonly known today began, Shoot a 2x4 at brick and block building components: probably doable; wood siding: might be doable; steel/wood doors: seems doable; a window with a piece of glass: are you crazy? But guess what? It was doable after all. As the development of the impact and cycling standards began the “probably”, “might be”, and “seems doable” were not doable at first. The 2x4 went right through. After many rounds of R&D testing a standard was finally developed, and the “not doable” became “doable” after all. But many felt the standards were unrealistic and would not gain acceptance. Guess what? Many people were wrong.
Click on the Kawneer website link below to learn more about missile test specifics.
The South Florida Building Code was the first to adopt impact testing standards, known as “Protocol PA 201-94 Impact Test Procedure” and “Protocol PA 203 Criteria for Testing Products Subject to Cyclic Wind Pressure Loading”. Additionally, the Southern Building Code Congress International (SBCCI) published its “SSTD 12-9 SBCCI Test Standard for Determining Impact Resistance from Windborne Debris”. The American Society for Testing and Materials (ASTM) got in the game in 1997 when it released its first publication, “ASTM E 1886-97 Standard Test Method for Performance of Exterior Windows, Curtain Walls, Doors and Storm Shutters Impacted by Missile(s) and Exposed to Cyclic Pressure Differentials”, to address the growing trend. In 1999 ASTM published its second document “ASTM E 1996-99 Standard Specification for Performance of Exterior Windows, Curtain Walls, Doors and Storm Shutters Impacted by Windborne Debris in Hurricanes”. In 2000 the American Architectural Manufacturers Association (AAMA) published “AAMA 506-00 Voluntary Specifications for Impact and Cycle Testing of Fenestration Products”. Enough about testing procedures? Not quite. In 2001 The Florida Building Commission published its first state wide building code known as the Florida Building Code (FBC) 2001. With the FBC came additional requirements known as Test Protocols for High Velocity Hurricane Zones, which established Testing Application Standards (TAS), TAS 201-94 Impact Test Procedures and TAS 203-94 Criteria for Testing Products Subject to Cyclic Wind Pressure Loading.