This CE Center article is no longer eligible for receiving credits.
It struck with unexpected intensity the morning of August 24, 1992. Elliott Key was the first to feel its wrath; some 25 minutes later, Homestead, Florida, was in the bull’s-eye.
Hurricane Andrew’s August rampage in 1992 would become the costliest natural disaster in United States history to that date, and today it’s surpassed only by totals from Hurricane Katrina (2005), Hurricane Sandy (2012), and Hurricane Ike (2008). In all, the damage caused by Andrew in South Florida and Louisiana totaled $26 billion. Sixty-five deaths were attributed to the storm, while around 150,000 to 250,000 people in South Florida were left homeless. Approximately 600,000 homes and businesses were destroyed or severely impaired by the winds, waves, and rain. Communications and transportation infrastructures were significantly impaired, and there was tremendous loss of power and utilities, water, and other essentials.
Photo courtesy of Graham Architectural Products
Project: The Conservatory at Hammock Beach
Projects requiring hurricane-resistant windows and doors no longer have to compromise on aesthetics.
The Fallout from Hurricane Andrew
The lives lost and billions of dollars in damages served as a wake-up call for the construction industry.
Wind zone levels were not adequate, the existing standards were not being adhered to, and codes were not being enforced. As a result, missile impact test standards were developed and more stringent building codes have been put in place that are now enforced.
The damage and devastation brought by Hurricane Andrew in 1992, both physically and financially, spurred the industry to reevaluate building codes. In the many areas of the United States impacted by tropical storms and hurricanes, revised codes and standards became the key to better emergency preparedness.
Photos courtesy of the National Renewable Energy Laboratory/Solar Outdoor Lighting
These photos were taken before and after Hurricane Andrew. The destruction caused by Hurricane Andrew ushered in major changes to building codes all along the U.S. eastern seaboard and set the performance bar for hurricane-resistant products.
Anatomy of a Disaster
“Hurricanes form both in the Atlantic basin to the east of the continental United States (that is, in the Atlantic Ocean, the Gulf of Mexico, and the Caribbean Sea) and in the Northeast Pacific basin to the west of the United States,” writes Chris W. Landsea, researcher at the Atlantic Oceanographic and Meteorological Laboratory in Miami. “The hurricanes in the Northeast Pacific almost never hit the United States, however, whereas the ones in the Atlantic basin strike the U.S. mainland just less than twice a year on average.”
Close to seven hurricanes every four years strike the United States, while about three major hurricanes cross the U.S. coast every five years, according to the National Oceanic and Atmospheric Administration (NOAA).
The top 10 costliest hurricanes have all occurred since 1992, with the top three occurring within the past 12 years. Hurricane Katrina in 2005 was the costliest natural disaster as well as one of the five deadliest hurricanes in the history of the United States, with damages over $108 billion. Hurricane Sandy in 2012 ranks second with $65 billion, and Hurricane Ike in 2008 narrowly surpassed the damages from Hurricane Andrew in 1992, with total losses at $29.5 billion.
While 40 percent of all U.S. hurricanes hit Florida and 88 percent of major hurricane strikes hit either Florida or Texas, hurricanes have impacted states as far north as Maine, New Hampshire, and Massachusetts (NOAA).
Hurricanes are classified on the Saffir-Simpson Scale, based on sustained wind speeds and damage caused. Categories begin at One, the least severe event, and go up to Five, the most severe.
- Category One: 74 to 95 mph
- Category Two: 96 to 110 mph
- Category Three: 111 to 130 mph
- Category Four: 131 to 155 mph
- Category Five: Greater than 155 mph
It struck with unexpected intensity the morning of August 24, 1992. Elliott Key was the first to feel its wrath; some 25 minutes later, Homestead, Florida, was in the bull’s-eye.
Hurricane Andrew’s August rampage in 1992 would become the costliest natural disaster in United States history to that date, and today it’s surpassed only by totals from Hurricane Katrina (2005), Hurricane Sandy (2012), and Hurricane Ike (2008). In all, the damage caused by Andrew in South Florida and Louisiana totaled $26 billion. Sixty-five deaths were attributed to the storm, while around 150,000 to 250,000 people in South Florida were left homeless. Approximately 600,000 homes and businesses were destroyed or severely impaired by the winds, waves, and rain. Communications and transportation infrastructures were significantly impaired, and there was tremendous loss of power and utilities, water, and other essentials.
Photo courtesy of Graham Architectural Products
Project: The Conservatory at Hammock Beach
Projects requiring hurricane-resistant windows and doors no longer have to compromise on aesthetics.
The Fallout from Hurricane Andrew
The lives lost and billions of dollars in damages served as a wake-up call for the construction industry.
Wind zone levels were not adequate, the existing standards were not being adhered to, and codes were not being enforced. As a result, missile impact test standards were developed and more stringent building codes have been put in place that are now enforced.
The damage and devastation brought by Hurricane Andrew in 1992, both physically and financially, spurred the industry to reevaluate building codes. In the many areas of the United States impacted by tropical storms and hurricanes, revised codes and standards became the key to better emergency preparedness.
Photos courtesy of the National Renewable Energy Laboratory/Solar Outdoor Lighting
These photos were taken before and after Hurricane Andrew. The destruction caused by Hurricane Andrew ushered in major changes to building codes all along the U.S. eastern seaboard and set the performance bar for hurricane-resistant products.
Anatomy of a Disaster
“Hurricanes form both in the Atlantic basin to the east of the continental United States (that is, in the Atlantic Ocean, the Gulf of Mexico, and the Caribbean Sea) and in the Northeast Pacific basin to the west of the United States,” writes Chris W. Landsea, researcher at the Atlantic Oceanographic and Meteorological Laboratory in Miami. “The hurricanes in the Northeast Pacific almost never hit the United States, however, whereas the ones in the Atlantic basin strike the U.S. mainland just less than twice a year on average.”
Close to seven hurricanes every four years strike the United States, while about three major hurricanes cross the U.S. coast every five years, according to the National Oceanic and Atmospheric Administration (NOAA).
The top 10 costliest hurricanes have all occurred since 1992, with the top three occurring within the past 12 years. Hurricane Katrina in 2005 was the costliest natural disaster as well as one of the five deadliest hurricanes in the history of the United States, with damages over $108 billion. Hurricane Sandy in 2012 ranks second with $65 billion, and Hurricane Ike in 2008 narrowly surpassed the damages from Hurricane Andrew in 1992, with total losses at $29.5 billion.
While 40 percent of all U.S. hurricanes hit Florida and 88 percent of major hurricane strikes hit either Florida or Texas, hurricanes have impacted states as far north as Maine, New Hampshire, and Massachusetts (NOAA).
Hurricanes are classified on the Saffir-Simpson Scale, based on sustained wind speeds and damage caused. Categories begin at One, the least severe event, and go up to Five, the most severe.
- Category One: 74 to 95 mph
- Category Two: 96 to 110 mph
- Category Three: 111 to 130 mph
- Category Four: 131 to 155 mph
- Category Five: Greater than 155 mph
Understanding Potential Damages from Hurricanes
Category One: Very dangerous winds will produce some damage. Well-constructed frame homes could have damage to roofs, shingles, vinyl siding, and gutters. Large branches of trees will snap, and shallowly rooted trees may be toppled. Extensive damage to power lines and poles likely will result in power outages that could last a few to several days.
Category Two: Extremely dangerous winds will cause extensive damage. Well-constructed frame homes could sustain major roof and siding damage. Many shallowly rooted trees will be snapped or uprooted and block numerous roads. Near-total power loss is expected, with outages that could last from several days to weeks.
Category Three: Devastating damage will occur. Well-built framed homes may incur major damage or removal of roof decking and gable ends. Many trees will be snapped or uprooted, blocking numerous roads. Electricity and water will be unavailable for several days to weeks after the storm passes.
Category Four: Catastrophic damage will occur. Well-built framed homes can sustain severe damage with loss of most of the roof structures and/or some exterior walls. Most trees will be snapped or uprooted and power poles downed. Fallen trees and power poles will isolate residential areas. Power outages will last weeks to possibly months. Most of the area will be uninhabitable for weeks or months.
Category Five: Catastrophic damage will occur. A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.
Why Windows Fail
Windows and doors play a vital role in any structure. They act as centerpieces for design and architectural style, while also capturing natural daylight, allowing ventilation, and providing views.
Photo courtesy of the U.S. Navy/Interior Communications Electrician 1st Class Jason Stephens
Windows in a high-rise building in downtown Houston were shattered by winds from Hurricane Ike after the storm came ashore on the Texas Gulf Coast early Saturday morning, September 13, 2008 as a major hurricane. The storm left broken windows, flooded streets, and millions of Texans without power.
Under assault from a hurricane, however, improper windows go from enhancing a building to becoming its weakest link.
As hurricanes sweep onshore, they bring an arsenal of destructive forces with them. When a hurricane makes landfall, it often produces a devastating storm surge, or an abnormal wave of water sweeping inland at high speed. A hurricane’s high winds torque, twist, and flatten structures, and pick up and launch debris, creating wind-borne projectiles. Hurricane winds can spawn tornadoes. Finally, torrential rains cause floods and landslides, destabilizing what remains standing.
There are three main reasons why windows fail during a hurricane or severe storm event:
1) Glass breaks from wind pressure or more likely from windborne debris
2) Whole windows, frames and all, can be blown into the structure
3) Water infiltrates the joints of windows or leaks around the frames and into wall cavities
Wind-borne debris, or airborne projectiles that cause glass breakage and other damage to buildings during severe wind events, are one of the major causes of damage during a hurricane.
When a window is broken during a hurricane, water, glass, and debris are blown immediately into the structure. Flying glass and debris can cause serious injury and death. In addition, a failed window opens up the building to the full consequences of the storm. Depending on the location of the breached opening, with respect to wind direction during a hurricane, broken windows in the exterior envelope allow strong winds to rush inside the building. These trapped wind forces create extremely high internal pressures on the roof, sidewalls, and leeward wall that exceed the total wind pressure resistant limitation of the building’s structural elements. Consequently, the internal pressures can ultimately result in severe damage to, if not total destruction of, the building.
Mitigating damages from debris is a principle priority in hurricane-resistant windows and doors.
Beyond broken glass from high winds and projectile impacts, entire window systems may fail from wind forces on the assembly. In older buildings, if the window is not anchored into the wall well enough to resist high wind pressure, the entire window may be lost. While a 50-mph wind pushes on a window or door with about 5 to 7 pounds of force per square foot, a 100-mph wind applies 20 to 28 pounds per square foot. A 130-mph wind applies 34 to 47 pounds per square foot. An average 3-foot by 5-foot residential bedroom window, when subjected to a 100-mph wind, has between 300 to 420 pounds of force applied to the window and the frame.
Windows and doors that have been tested and rated for high levels of water resistance will perform better and allow less or no water into the structure.
After being confronted full force in 1992 with just how much devastation hurricanes could cause, codes and standards were dramatically revised. Codes for windows in any zone with a hurricane threat now address:
- Higher wind loading: Coastal wind load charts were redefined significantly higher.
- Negative pressures: Building components are required to withstand high wind loads; greatest impact realized from negative pressure loads.
- Impact and cyclic testing: Cladding and building components must be tested and certified for compliance.
Disaster Response: Hurricane-Resistant Requirements for Windows
ASCE 7
ASCE 7: Minimum Design Loads for Buildings and Other Structures provides requirements for general structural design and includes means for determining dead, live, soil, flood, wind, snow, rain, atmospheric ice, and earthquake loads, as well as their combinations, which are suitable for inclusion in building codes and other documents. These measures have been put in place to protect both property and lives as a result of significant changes in the building codes over the past two decades. Many codes and standards now contain hurricane provisions. Codes originally developed for Florida have expanded from Texas, along the Gulf, and up through the Atlantic seaboard to Maine. Windborne debris requirements are significant new factors in model building codes.
The American Society of Civil Engineers (ASCE) 7 is referenced in major U.S. model building codes. Hurricane provisions in ASCE 7 include:
- Definition of Hurricane-prone regions and Windborne debris regions
- Definition of impact-resistant glazing and impact-resistant coverings
Under ASCE 7, hurricane-prone regions are defined as U.S. Atlantic Ocean and Gulf of Mexico coasts where the basic wind speed is greater than 115 mph, as well as Hawaii, Puerto Rico, Guam, Virgin Islands, and American Samoa.
Wind debris regions are those areas within hurricane-prone regions located either within 1 mile of the coastal mean high water line, where the basic wind speed is equal to or greater than 130 mph, and in Hawaii, or in areas where the basic wind speed is equal to or greater than 140 mph.
Under this definition, a large portion of U.S. coastal regions fall within ASCE 7 requirements; all coastal areas from Texas to Maine are now regarded within ASCE 7 governance.
The current version of ASCE 7 is ASCE 7-10. Wind design in ASCE 7-10 incorporates several major changes. ASCE 7-10 wind maps are based on “ultimate strength” wind speeds, as opposed to “allowable stress” wind speeds used in ASCE 7-05. Additionally, ASCE 7-10 introduces new wind speed maps that vary by risk category instead of occupancy category. Risk category for a structure is rated as either a I, II, III, or IV and is defined by the nature of occupancy of the building.
- Risk Category I: Low hazard to human life. Examples include agricultural facilities, certain temporary facilities, and minor storage facilities.
- Risk Category II: Any building and other structure not listed in Categories I, III, and IV; Residential homes.
- Risk Category III: Substantial hazard to human life. Examples include building and other structures whose primary occupancy is public assembly, with an occupant load greater than 300; buildings and other structures containing elementary, secondary school, or day-care facilities with an occupant load greater than 250; adult education facilities with an occupant load greater than 500.
- Risk Category IV: Designation as an essential facility. Essential facilities include, but are not limited to, fire, rescue, ambulance and police stations, and emergency vehicle garages; designated earthquake, hurricane, or other emergency shelters; power-generating stations and other public utilities facilities required as emergency backup facilities; Categories I and II occupancies having surgery or emergency treatment facilities; buildings and other structures having critical national defense functions.
Photo courtesy of Graham Architectural Products
Under ASCE 7-10, a building’s purpose and occupancy level help determine risk. Structures containing elementary and secondary schools are viewed as higher risk and subject to more stringent requirements. Hurricane-resistant windows are featured throughout historic Leon High School in Tallahassee, Florida.
The International Building Code (IBC) and Florida Building Codes reference ASCE 7 to calculate a project’s “design pressure.”
After defining where hurricane-prone regions and windborne debris regions are, and setting structure risk categories, ASCE 7 also mandates debris impact provisions. These provisions can be divided into two categories:
- Glazing, impact-resistant: Glazing which has been shown by an approved test method to withstand the impact of windborne missiles likely to be generated in windborne debris regions during design winds.
- Impact-resistant covering: A covering designed to protect glazing, which has been shown by an approved test method acceptable to the authority having jurisdiction to withstand the impact of windborne missiles likely to be generated in windborne debris regions during design winds.
Glazing located more than 60 feet above ground and more than 30 feet above aggregate surface roof debris located within 1,500 feet of the building shall be permitted to be unprotected. To assure compliance, ASCE 7 references ASTM E1886 and E1996 testing methods for windborne debris performance validation.
Verifying Window Performance under ASCE 7
Impact and cycling tests have been developed to simulate large and small windborne debris encountered during a hurricane. Application of these tests demonstrates whether glazing and coverings are impact resistant. Positive and negative pressure cycling is also imposed on the products to reproduce the extreme gusts of wind during the hurricane event.
Tests evaluate two categories of debris encountered during a hurricane:
- Large missiles: Objects such as timbers, roof tiles, sheet metal, and bricks that fly or tumble near ground. Impact speed 1/3 to 1/2 of wind stream velocity. Larger missiles tended to fly and tumble within 30 feet of the ground, while small missiles fly at heights up to 30 feet above small missile sources. Large missiles such as roof tile, concrete blocks, timbers, sheet metal, and fascia are common during a hurricane. For testing, the 2-foot by 4-foot timber was determined to be representative of objects that commonly fly in hurricanes and was found to be easily propelled from an air cannon in a repeatable manner. Several different masses of 2-foot by 4-foot timbers have been defined for design use.
- Small missiles: Objects such as roof gravel or glass particles that fly at rooftop elevations. Impact speed 90 percent of wind stream velocity. Small missiles tend to fly at greater heights than large missiles. The most common small missile is roof gravel, but broken glass particles, bits of roofing material, and small chips of concrete and clay tile also have been observed. A 2-gram steel ball is considered representative of small missiles that fly in windstorms and is used during testing.
Photo courtesy of Graham Architectural Products
During launch missile impact testing, a 2-inch by 4-inch wood stud traveling nearly 35 mph is launched at the center of the window. To pass this phase, a window must successfully withstand impacts at the center and corner of the window.
ASTM E1886/1996 are the national consensus test method and specifications for windborne debris impacts in hurricanes.
The American Society for Testing & Materials (ASTM) has strict guidelines (E1886 and E1996) for impact-resistant windows before they can be certified as impact resistant. The debris impact test method is defined by ASTM E1886-02; specific impact requirements are defined in specification ASTM E1996-02. ASTM E1996 augments ASTM E1886 by specifying the weight of the large missile to be used in testing per ASTM E1886 and the impact velocities for the large and small missiles. The ASTM standards identify more stringent requirements for buildings in higher basic wind speed zones and for critical facilities.
Codes will vary by community, but generally, impact-resistant windows must meet these basic guidelines:
- The first test is called a launch missile impact test. A 9-pound, 2-inch by 4-inch wood stud is launched at 50 feet per second (fps), or almost 35 miles per hour, at the center of the window. If the window doesn’t fail, another stud is then shot at one of the corners of the window. Both the center and the corner of the window must be able to hold together to pass this test. Hurricane-prone Florida has slightly tougher testing standards, requiring windows to withstand boards launched at 80 fps.
- After the launch missile impact test, the window is then subjected to pressures that simulate winds of up to 200 miles per hour. If the window remains intact within the frame, it can be certified as an impact-resistant window.
Photo courtesy of Graham Architectural Products
Selecting impact-resistant windows, rather than shutter systems, allows for preservation of design and total preparedness of a structure during a storm. On the National Register of Historic Places, The Cigar Factory in Charleston, South Carolina, selected hurricane-resistant windows to preserve its Victorian-era industrial facade.
A product is considered large missile resistant after it has been exposed to various impacts with a piece of lumber weighing approximately 9 pounds, measuring 2 inches by 4 inches by 6 feet (no more than 8 feet) in size, traveling at a speed of 50 feet per second (34 mph). Then the product must pass positive and negative wind loads for 9,000 cycles, with impact creating no hole larger than 1/16 by 5 inches in the interlayer of the glass.
A product is considered small missile resistant after it has been exposed to various impacts with 10 ball bearings traveling at a speed of 80 feet per second (50 mph). The product is then subjected to wind loads for 9,000 cycles.
For buildings where doors and windows are located 30 feet or less above grade (e.g., above ground level), the products must pass the large missile test. If the doors and windows are more than 30 feet from the ground, they must be either large or small missile certified.
Impact-resistant windows offer several advantages over shutters. A product with hurricane-resistant status will offer 24-hour protection with no action required. Windows that are hurricane-resistant offer a more aesthetically appealing alternative to shutters. The use of impact-resistant windows and doors may also help reduce insurance premiums.
Other impact test standards may be encountered during project specification, depending on job location. These include Testing Application Standard (TAS) 201, 202, and 203 and Miami Dade Impact and Cycling Codes in the Florida Building Code (FBC).
Photo courtesy of Graham Architectural Products
Project: The Conservatory at Hammock Beach
To withstand the rigors of testing and secure a hurricane-resistant rating, hurricane-resistant windows require special glazing and extra attention to both frame and assembly.
The Components of a Hurricane-Resistant Window
To withstand the rigors of testing and secure a hurricane-resistant rating, hurricane-resistant windows require special glazing and extra attention to both frame and assembly. The type of glass used in hurricane-resistant windows is called laminate glazing. Laminated glass, sometimes also referred to as “safety glass,” consists of two or more panes of glass with one or more layers of polyvinyl butyl (PVB), urethane, or resin sandwiched between them and treated. The glass panes can be basic float glass, tempered glass, or heat-strengthened panels. The number of layers of each sheet of glass and the thickness of each, and the laminate interlayer, can be varied in order to achieve the required performance. Laminated glass provides durability, high-performance, and multifunctional benefits while at the same time preserving the aesthetic appearance of glass. Besides its requirement in hurricane-resistant products, laminate glazing is also found in designs for earthquake and ballistic and blasts zones.
Laminate glazing is specified for hurricane-resistant windows because of the unique properties of the glass and interlayer blend. Ordinary glass windows are brittle and, when broken, tend to break into long sharp pieces, which can cause serious and sometimes fatal injuries. In laminate glass, the interlayers have the capacity to absorb the energy of impact and resist penetration. Safety hazards caused due to breakages are minimized with the use of laminated glass. In the event that the glass is broken, fragments tend to adhere to the PVB interlayer, mitigating the risk of injury from falling glass and helping to resist further impact or weather damage. A PVB membrane or other interlayer adds good tenacity performance so that if the laminated glass breaks due to violent force, the PVB will absorb a large amount of impact energy and disperse it rapidly. Therefore, it is hard to break the laminate glass and the shape of the glass may be maintained, even if broken. Any glass fragments will adhere to the plastic interlayer, minimizing the risk of injury and property damage.
Sealed insulating laminated impact glass is also available to provide improved thermal efficiencies. Laminated glass reduces the amount of sound that is transmitted, earning a higher sound transmission class (STC) rating than traditional glazing and creating a quieter, more comfortable interior environment.
Depending on how it is manufactured, laminate glazing can also be more energy efficient. Laminated glass also filters out more than 99 percent of the sun’s harmful ultraviolet rays, helping to reduce fading of interior materials.
Compliance with enhanced energy codes is driving a new trend in laminate glazing. Traditionally, laminated glass is placed to the outside of a glazing unit, in the outboard position. This makes insulative low-e coatings prohibitively expensive or even unsourceable. Today’s design trend has certain suppliers offering laminate glazing in the inboard position, with a traditional piece of glass outboard. This position allows the outboard lite great flexibility, as the traditional glass can receive colored glass, energy coatings, and simulated divided lites, without affecting the integrity of the laminate glazing inboard.
Laminate glazing is only part of the hurricane-resistant window story. Anchorage and frame assembly are just as vital. When hurricane-resistant systems are tested, it is an evaluation of the entire system. It takes an entire window system to make an impact-resistant opening. While the earliest hurricane-resistant products were often limited to fixed, monolithic rectangles, which severely limited aesthetics, advances in technology have engineered a full range of frames and sashes that can duplicate the looks of traditional products and even replicate historic facades.
Frames for impact-resistant windows or doors may be constructed from wood, metal, vinyl, or any combination thereof. However, frames are generally heavier than those made for regular residential windows. Wind force experienced during a hurricane can be strong enough to cause an entire window frame to give way from its anchorage in the envelope. Certain manufacturers add stiffeners and reinforcements, like steel, to help support storm impacts, along with high-performance anchorage systems to provide a complete hurricane-resistant window system.
To ensure a window is hurricane resistant and has successfully passed ASTM procedures and other testing standards, it is important to look for a manufacturer who is a member of and certifies their product to the American Architectural Manufacturers Association, or AAMA. AAMA membership and certification helps to ensure quality performance and consistency in manufacturing.
Specifying Hurricane-Resistant Windows in the Field
When specifying hurricane-resistant windows and doors, there are several general guidelines:
- Consult local and regional code.
- Determine design pressures required.
- Decide what window type is desired or required.
- Establish whether the products selected have been tested or undergone engineering analysis.
- Decide what mulling options are, if required.
- Determine what anchorage is required to meet design pressures and code.
- Verify that possible manufacturers participate in a third party certification program like AAMA.
Hurricane codes and requirements can be confusing in and of themselves. Add to that specific local mandates, such as those in Texas and Florida, and the picture only gets murkier. In Florida, two different hurricane testing procedures are recognized: ASTM and TAS. While close, these testing procedures are not the same. A common misperception is that the entire state requires unique TAS testing, yet only Miami Dade and Broward county projects involve TAS impact and cycling protocols. A familiarity with requirements specific to the project will allow confidence when selecting manufacturers with certified products.
Photo courtesy of Graham Architectural Products
Project: Westin Hotel, Village of Imagine, Orlando, Florida
While specifying windows in hurricane zones involves extra steps, understanding regional requirements and product certifications means selecting and building with confidence. Westin Hotel, Village of Imagine, Orlando, Florida
Clarity early on about project goals, design, and codes is a key to success for both the project and the budget. Manufacturers must choose a test size window to demonstrate a product’s hurricane resistance. If changes are later made that would alter the size of the window to a larger unit or the window’s operation, that product may no longer meet testing or may require additional testing, which is expensive. Providing a window and wall chart allows a window manufacturer to determine what it can and can’t supply. Making sure risk category, exposure category, and wind speeds are clearly defined also ensures testing is performed correctly the first time. Verifying if any unique attachments are required based on code and manufacturer is also vital. While some manufacturers have impact products certified with standard attachment methods, helping architects detail and draw products, those units that may rely on a different system integration method need to be called out.
Specifying correctly means defending the integrity of a building and the lives of its occupants. By keeping in mind several key points: that the window system is tested, not just the glass; that there can be no substitution of components; that large or small missile tests must be conducted depending on elevation; and that there are many different possible glass interlayers; and carefully examining the test report for maximum size, a project can proceed into a storm with confidence.
Through the Storm in Style
While certified window units require glass and frames that have surpassed requirements for high-velocity hurricane zones, leading manufacturers can not only deliver products that perform, but products that perform in style. Depending on the manufacturer, all styles and configurations of window may be available for selection, making protection from tropical storms no harder than any other building project, without compromising aesthetics.
Photo courtesy of Graham Architectural Products
Project: 930 NoMo, Charleston, South Carolina
Developed by Campus Works, one of the largest student housing firms in the Southeast, the construction was self-performed by Campus Works. The project is a six-story private apartment facility geared to college students and within close proximity to several colleges and universities. Bronze and white windows lend detail to the exterior; windows are both fixed and casement style. All windows are hurricane resistant.
Confidence in the Face of Chaos
Hurricane-resistant windows and doors provide life and property protection from hurricanes and typhoons and windborne debris. After the damage and devastation brought by Hurricane Andrew in 1992, the industry reevaluated its building codes in order to ensure better emergency preparedness. Not only was testing scientifically developed to safeguard window performance during a real storm, but hurricane and wind debris codes were also expanded, encompassing the entire U.S. eastern seaboard. Today, hurricane windows are manufactured to perform under extreme wind loading, negative pressures, and windborne debris impact and cyclic testing.
While the first hurricane-certified units were monolithic rectangles with little aesthetic diversity, designed solely to meet code requirements, with innovations in frame and glazing technology, today, any style, even historical replication, can be achieved and certified. With these advancements, not only can hurricane-resistant windows perform in a storm, they can preserve the historical buildings and design gems they are placed in.
Amanda Voss, MPP, is an author, editor, and policy analyst. Writing for multiple publications, she also serves as the managing editor for Energy Design Update.
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Graham Architectural Products manufactures the most innovative and highest-quality products in the fenestration industry. We achieve this by developing customized, performance-based products and by providing solutions to architects’ fenestration challenges. We earn and retain the architectural community’s trust with our experience, expertise, and collaborative spirit. www.grahamwindows.com
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