How and Why Laminated Glass Solutions Meet Expanding Hurricane Code Requirements

With hurricane-prone states adopting new building codes laminated glass with its many benefits takes on an increasingly critical role.

Karin Tetlow

Born in the 1930s, when a consortium of companies was asked to develop a clear, tough, adhesive material that could be manufactured efficiently into automobile windshields, laminated glass has become a necessity in the arsenal of building products. Not only does it provide the means for creating soaring winter gardens and light-filled concert halls, but it also offers a solution to many of today's complex building demands. But it was not until relatively recently that authorities appreciated the fact that laminated glass plays a critical role as safeguard against natural hazards such as hurricanes.

In 1992, after Hurricane Andrew ripped through South Florida, Miami-Dade County was the first to act on the need for building code requirements that address impact resistant glazing products. Since then, a number of states along the Atlantic and Gulf Coasts have followed suit with the result that there are now hundreds of products on the market, and even more expected. Since laminated glass is a critical component of glazing systems designed to withstand hurricane-force wind and rain, an understanding and familiarity regarding its testing and wide-ranging benefits, is fast becoming essential.

Florida Hospital Waterman is a 204-bed, state-of-the-art acute care hospital serving the Lake County, FL community. Impact resistant windows provide patients with a view to the outside, while protecting them from severe weather. Courtesy of: DuPont Glass Laminating Solutions

A Wake-Up Call

The second most costly catastrophe in the U.S.- Hurricane Katrina is the first-Hurricane Andrew claimed 65 lives, destroyed or severely damaged 600,000 homes and businesses and caused more than $25 billion in property damage. Post-storm investigations by the Dade County Building Code Evaluation Task Force determined that the most significant hurricane damage was from the loss of integrity of the building envelope when the exterior of a structure was breached. And that the leading cause of the severe property destruction was window and door penetration caused by debris blown by the 145 mph winds. Subsequent reviews of damage documentation, insurance records, and computer simulations of building failures confirmed the decisive role of windborne debris in causing damage, reports Joseph E. Minor, P.E., F.ASCE in the Journal of Architectural Engineering, Vol. 11, No. 1, March 1, 2005. He also points out that the immediate result of failures of windows and doors was an increase in internal pressure which, in combination with overall roof uplift pressures, initiated a chain of events that included removal of roof sheathing, wind and rain entering the building and the beginning of progressive failure of the building frame.

As a result of the findings, Miami-Dade County and industry representatives worked together to develop requirements that addressed impact protection of building openings that directly applied to windows, doors, skylights, storefront and curtain wall systems. The South Florida Building Code with its hurricane mitigation provisions was implemented in September of 1994. In 2002 the improved structural portions of the South Florida Building Code were absorbed into the Florida Building Code as the High Velocity Hurricane Zone provisions, which are applicable within Miami-Dade and Broward Counties.

Monolithic Glass Breakage Velocities from 2 gm Roof Gravel Mean minimum break velocity of¼ in glass from impact of 2 gm roof gravel from Minor et al. 1978 Wind speed for significant amounts of 2 gm roof gravel to leave roofs without parapets from Kind and Wardlaw 1976 Speed of 2 gm roof gravel after accelerating over 100 ft in 100 mi / h wind from Minor et al. 1978 Annealed glass Heat- strengthened glass 100 mi / h 70 ft / s 23 ft / s 36 ft / s Note: 1 gm=0.0044 lb; 1 ft =0.305 m; 1 mi / h=1.6 km/ h; 1 ft / s =0.305 m/ s Source: Lessons Learned from Failures of the Building Envelope in Windstorms, Joseph E. Minor, P.E., F.ASCE, Research Professor, Univ. of Missouri−Rolla, Journal of Architectural Engineering, Vol. 11, No. 1, March 1, 2005

Even very small amounts of gravel flying at sufficient speed will break the three basic types of monolithic window glass. Laminated glass, which tends to stay in the window opening when broken, is required to meet hurricane impact building codes.

Building code requirements apply to glazing systems, which comprise frame, attachments and the glazing infill. Window and door, skylight and curtain wall manufacturers, therefore, apply an integrated approach to designing their systems in order to pass missile impact and cycling tests, as well as required air, water and structural tests.

Laminated glass is a critical component of any impact resistant glazing system. It is manufactured by sandwiching "interlayers" (generally tough polymer sheet materials) between two pieces of glass and forming them into a composite by controlled processes combining heat and high pressure. The processing typically is done in large autoclaves capable of making finished, laminated glass suitable for buildings.

Its major benefit is that it remains intact even if broken, providing a weather barrier that reduces the likelihood of total collapse due to internal pressurization of the structure or widespread water damage. When adhesive plastic interlayers such as polyvinyl butyral (PVB) are laminated between glass, the plastic absorbs the energy of the impact, thus resisting penetration. This helps both hold the glazing system together even if the glass breaks and prevent injuries related to flying glass or exposed shards. When windows and doors are impact resistant, there is no need to board up window openings when a hurricane advisory is issued. Nor is there a need for the activation or mounting of shutters.

Depending on the location, size of the panels, and design pressures, the interlayer used in the laminate may be of different thicknesses or types. For example, a .060-in PVB interlayer is a typical thickness and type of interlayer for small missile glazed areas. Other stiffer, more structural, interlayers, in thicknesses of .090 and .100-in, provide better resistance to tearing when subjected to large missile impacts at higher design pressures. The strength and other properties of laminated glass can be tailored to meet specific needs.

Test Requirements and Standards

The Miami-Dade County test requirements currently define two distinct impact areas on a structure. Large missile impact resistance for glazing systems is required for the first 10 meters or 30 feet above the finished grade. Above the first 10 meters, small missile resistance is required for glazed openings to the top of the structure. The large missile impact test requires two impacts per specimen using a 9-pound 2-foot x 4-foot wood timber traveling at 50 feet per second. The small missile test requires two impacts to the glazing system, each with ten 2-gram steel balls traveling at 130 feet per second.

Once impacted, the test specimens are subjected to 9,000 pressure cycles, 4,500 positive pressure cycles and 4,500 negative pressure cycles. Failure is defined as a tear greater than 1/16-inch x 5-inches.

In 2002, the ASTM E1886 Test Method for Exterior Windows, Curtain Walls, Doors, and Impact Protective Systems Impacted by Missile(s) and Exposed to Cyclic Pressure Differentials was finalized. Similar to the Dade County protocol, the ASTM standard has both the large and small missile requirements. There are, however, some differences. In most areas, only one impact location is required per specimen. Two impact locations for each specimen are required in wind zones greater than 140 mph and within 1 mile of the coast. Failure is defined as an opening through which a 3-inch sphere can pass. No impact is required on the mullion outside of the 140 mph wind zone. Small missile impact resistance is required from 30 to 60 feet in height above grade.

Protection Zones − Large Missle Requirement
Level of protection	Wind Rating (mph)	Basic Protection	Enhanced Protection
Zone 1	110-119	C	D
Zone 2	120-129 (> 1 mile from coast)	C	D
Zone 3	120 to 129 ( < mile) 130 to 139	D	E
Zone 4	> 140	D	E
Source: ASTM E 1996-06

Missile Type and Speed for Basic and Enhanced Protection
Missile Level	Missile Type	Missile Speed
A	2 gm steel ball	130 ft/sec
B	2 lb. 2 x 4	50 ft/sec
C	4.5 lb. 2 x 4	40 ft/sec
D	9 lb. 2 x 4	50 ft/sec
E	9 lb. 2 x 4	80 ft/sec
Source: ASTM E 1996-06

In 2003, the ASTM E1996 Standard Specification for Performance of Exterior Windows, Curtain Walls, Doors, and Storm Shutters Impacted by Windborne Debris in Hurricanes was finalized. The specification created protection zones and additional missile types for users.

Specifiers seeking specific test requirements in the ASTM standards, must first identify the applicable wind rating for the site. This information is found in the American Society of Civil Engineering standard ASCE 7-98. Once the wind rating has been identified, the ASTM E1996 standard specifies the basic or enhanced protection requirements. In addition, the standard identifies the missile type and speed required for testing.

The International Building Code (IBC) defines a windborne debris region as one within hurricane-prone regions within one mile of the coastal mean high water line where the basic wind speed is 110 mph or greater; or where the basic wind speed is 120 mph. The IBC states that glazed openings located within 30 feet of grade shall meet the requirements of the large missile test of ASTM E1996 and glazed openings located more than 30 feet above grade shall meet the provision of the small missile test of ASTM E1996.

The Broward Center for the Performing Arts in Fort Lauderdale, FL was built before impact resistance requirements were adopted in the building codes. The 204,000 square foot facility opened in 1991 included 17,100 square feet of tall windows. After Hurricane Andrew, a decision was made to retrofit the windows with impact resistant laminated glass. Courtesy of: DuPont Glass Laminating Solutions

Test protocols for missile impact and pressure cycling are specified in the Florida Building Code, which includes the high velocity wind zone that applies to Miami-Dade and Broward Counties. According to the 2004 Florida Building Code, all Florida counties within the 110-150 mph wind zones have mandatory impact standards except for the northwest Florida Panhandle that specifies impact protection within one mile from the coast.

Hurricane Wilma Aftermath

But it was not until Hurricane Wilma struck South Florida on October 24, 2005, that improved structural building envelope provisions of the building code were put to the test in actual conditions. After causing widespread property damage in Cancun, Mexico, the hurricane made landfall in Southwest Florida near Naples as a Category 3 storm with sustained winds of 103 mph and a very large eye that was 55-65 miles across. The storm exited Florida in northern Palm Beach County only four hours later with the eye still intact and sustained winds of 104 mph. Due to the large size of the storm, heavily populated Dade, Broward and Palm Beach counties all felt the full effect of the winds.

Although the storm was reported to be only a Category 2 storm as it passed through South Florida, there was well-publicized glass breakage in high-rise buildings in Miami, Fort Lauderdale and West Palm Beach and in high-rise condominiums in North Miami Beach. Several buildings on Brickell Avenue in Miami had in excess of 1,000 lites of broken monolithic heat-treated glass. Much of the glass breakage was attributed to windborne debris. Storm investigations by various agencies confirmed that all of the high rise buildings that suffered glass damage were built under codes with lesser hurricane protection standards for high rise buildings than those currently in effect.

In a recent post-Hurricane Wilma study, buildings glazed with impact resistant laminated glass were surveyed to determine the extent of glass breakage and resulting damage to the property. The building types surveyed included condominiums, office buildings, government buildings, hospitals, retail buildings and hotels. Building sizes ranged from single story to multi-story high rises and locations included oceanfront, downtown urban and suburban. Glazing assembly types in the surveyed buildings included sliding glass doors, swing doors, operable windows, fixed glass and curtain wall systems.

Findings confirmed the need for adequate hurricane protection standards. Projects that reported broken or damaged laminated glass from windborne debris only experienced fractures of the glass layers. There were no reports of laminated glass failures resulting in breaches of the building envelope. The laminated glass performed as was intended and consistent with the pass-fail criteria of the Florida Building Code. "The requirement that all structures must have windborne debris protection represents the greatest success story regarding damage mitigation," concluded Miami-Dade County's 2006 Post Hurricane Wilma Progress Assessment.

Additional Benefits of Hurricane Impact Laminated Glass

The benefits of high impact laminated glass reach far beyond shard retention and battling flying debris. Those particularly applicable to hurricane zones relate to safety, noise reduction, intrusion resistance, greater bomb blast protection-and complying with the turtle code.

Safety from Accidental Injuries
Aside from hurricane impact requirements, glass installed in doors and large glass panels is often required to meet safety-glazing requirements designed to minimize cutting and piercing injuries resulting from accidental glass impact. Existing building code requirements are based on the federal safety-glazing standard, CPSC 16 CFR 1201, promulgated in 1977 by the Consumer Product Safety Commission. Two levels, Category I and Category II, define acceptable performance.

Sliding doors and windows of the Crawford residence were refitted with laminated glass to provide hurricane impact protection and reduce noise from the outside. Courtesy of: DuPont Glass Laminating Solutions

For Category I compliance, the glazing must withstand one 150 foot-pound impact produced by impacting the glazing material with a 100-pound shot bag from a vertical height of 18 inches. For Category II compliance, the glazing must withstand one 400 foot-pound impact produced by impacting the glazing material with a 100-pound shot bag from a vertical height of four feet. Pass-fail criteria for impacted laminated glass samples require that no openings are present which will allow the passage of a 3-inch diameter steel sphere.

Given the more rigorous testing standards required for hurricane impact resistance, hurricane glass will likely comply with building code requirements for safety.

Noise Control
Laminated glass used for hurricane impact resistance has proven to be an excellent barrier to noise, having a higher sound reduction index than monolithic glass of equal thickness between the frequencies of 125Hz and 3,000Hz. Compared with monolithic glass of the same thickness, laminated safety glass made with an engineered acoustical interlayer can reduce mid-frequency noise sensation by about one half. (Noises most objectionable to humans such as jet engines, dogs barking and electrical motors fall in the mid-frequency 1,000 to 3,000 Hz range.) Sound dampening is due to the "viscoelastic" properties of the interlayer material and varies depending on glass and interlayer thickness and softness.

Ray Crawford's waterfront home in South Florida incorporates more than 100 sq m of sliding doors and windows, affording the family a spectacular view of the water. With the view, however, came excessive noises from speedboats racing along the waterways. To solve this problem, Crawford decided to refit his home with laminated glass. He noted, "I knew it would allow us to continue enjoying clear, distortion-free views while solving our immediate noise problem."

Intrusion Resistance
Laminated glass ensures a safer building because glass interlayers retain glass fragments after breakage by intruders. This past June, employees of the Day Surgery Center in Winter Haven, Florida, arrived at work and noticed a broken window near the back of the facility. The exact motive for the break-in was unclear but, as employees surveyed the damage, they were relieved to find that nothing was missing or damaged. They realized, in fact, that the burglar never even entered the facility.

According to Dr. Robert Lerner, President of Physicians of Winter Haven, LLC, "When we were selecting windows for the surgical center, we wanted to provide hurricane protection, but the recent break-in attempt demonstrates the ability of laminated glass to resist impact as well." He noted that the burglar tried to remove the glass shards to gain entry, but his tools were no match for impact resistant glass, and he eventually fled the scene.

Blast Resistance
Laminated glass can be designed to withstand bullets and bomb blasts by using multiple or thick layers of glass and interlayer. The Wilkie D. Ferguson Jr. Courthouse in Miami is the first in the country designed to withstand both bomb blasts and hurricane-force winds. The new building, which spans two city blocks, is the largest federal courthouse in the United States and meets Miami's stringent hurricane codes as well as U.S. government security standards for blast mitigation. The courthouse is part of the GSA's Design Excellence Program, which commissions designers and artists to improve the design and quality of federal buildings.

Turtle Code Compliance
While architects may appreciate the many design and energy-saving options presented by laminated glass and its low-E and tinting options, those specifying glazing systems in hurricane zones, should be aware of the "Turtle Code." These are requirements intended to maximize protection of sea turtles that nest along the Atlantic and Gulf Coast beaches from May 1 to October 31 of each year. Sixty days after eggs are laid, the newborn hatchlings emerge. When they should head out to sea, the hatchlings, following their inborn tendency to move in the brightest direction, often become confused and are attracted back to the bright lights of the shoreline. As a result a number of local building codes or ordinances require a visible light transmittance of .45 or less on all new construction windows within line sight of the beach. A typical solution is to specify laminated glass with a tinted gray interlayer that falls within the acceptable visible light transmittance and meets hurricane impact requirements in coastal areas adjacent to turtle n

Glazing Recommendations

Glazing recommendations for architectural laminated glass are well established and published by the Glass Association of North America (GANA). The minimum requirements for typical commercial impact resistant glazing applications are 1/2-in or greater glass edge bite, 3/16-in or greater face clearance, and 1/4-in or greater edge clearance. Specific manufacturers may have special requirements regarding fastening, cleaning, spacing and contact with other materials. Because moisture near the laminated glass edge may have a deleterious effect on the adhesion of the glass to the interlayer, weep holes are recommended to prevent the accumulation of moisture in the glass pocket.

The windows of Cornerstone II office building in Fort Lauderdale, FL. were installed using a laborsaving dry glaxzing system. Courtesy of: DuPont Glass Laminating Solutions

Glazing Systems Performance

In addition to the laminated glass infill needing to meet impact requirements, the entire glazing system must meet dynamic performance criteria in large and small missile impact and cycle tests in order to manage impact events and loads of significant magnitude such as hurricane force winds. A common glazing solution for surviving the demanding dynamic loads applied to window test specimens is to adhesively bond the laminated glass composite to the supporting structure with a high performing architectural sealant. The design of this glazing detail is critical in order to achieve the maximum capability of the laminated glass infill. In hurricane regions with higher wind load requirements, the glass used in the laminate is required to be heat-treated.

Dry Glazed Systems

The most recent solution known as "dry glazing" uses gaskets in place of adhesives for large missile impact protection. Adopted within the past two years a dry glazed large missile impact system requires the use of a stiff interlayer within the glass laminate in order to limit deflection of the broken laminate during loading. Dry glazed large missile impact systems with laminate infill have been certified to +/- 90 psf for sizes up to 5 feet by 8 feet. Similarly sized laminated insulating glass systems achieve design pressures approximately 50% greater than systems using laminated glazing infill.

Applied to a field installed and glazed fenestration system, dry glazing can result in significant cost savings in labor and materials compared with wet glazed systems. Moreover, replacement of broken laminated glass infill is faster, easier and simpler. Sid Miller, whose company used dry glazing to install windows in the Cornerstone II office building in Fort Lauderdale, reports that in addition to savings in labor-setting the glass and running the gasket can be done at the same time thus eliminating the need for a caulker's return visit-dry glazing gives a more consistent performance since glazing pockets do not need to be cleaned of dust and contaminants.

Operating worldwide, DuPont Glass Laminating Solutions, E.I. du Pont de Nemours and Company provides improved personal safety, property protection, public security, energy efficiency and sustainable development through the use of laminated safety glass. From storm protection to life-saving accident and injury prevention, science-based products and services from DuPont Glass Laminating Solutions are helping people everywhere enjoy safer, healthier, more comfortable lives, while conserving energy and enjoying the view. DuPont was a founding company involved in the development of the laminated safety glass industry and remains a leading innovator in this field, offering the world's broadest range of traditional and specialty-performance interlayer technologies. dupont.com/safetyglass/en/productServices/index.html

State Building Codes
Building code requirements for impact protection have expanded beyond Florida as states have adopted the International Building Codes. Because the International Codes serve as models for the states or local jurisdictions, there are often differences in requirements from one state to another.

Texas
The Texas legislature has adopted the 2003 IRC and 2003 IBC, but has not established a Building Code Commission to administer the code and develop updates. The Texas Department of Insurance (TDI) has a strong program to enforce windborne debris protection. The area covered is essentially the same as found in the IRC and IBC, for about one half of the coastal counties. The TDI provides windstorm coverage to residential structures as long as they meet the program construction standards. TDI is currently reviewing the 2006 IRC with adoption expected in early 2007. Enforcement is at a very high level for TDI structures.

Louisiana
No form of statewide building code had existed until November, 2005, when Governor Kathleen Blanco signed Senate Bill 44 requiring common protection for 11 parishes along the coast-Calcasieu, Cameron, Vermillion, Iberia, St. Tammany, Orleans, Jefferson, St. Bernard, Plaquemines, Terrebonne and Lafourche. The legislation adopted the 2003 IRC and IBC and created the Louisiana Unified Construction Code Council to manage the code development process. The windborne debris area would include the entire area of each parish with wind maps being the responsibility of each parish. A major focus for the involved parishes is education for inspectors and the construction industry.

Mississippi
Governor Haley Barbour has signed HB1406 to establish a unified building code for five coastal counties-Jackson, Harrison, Hancock, Stone and Pearl River. The area has adopted the 2003 IRC and IBC, which contains windborne protection requirements. The other counties are not required to follow these codes. A provision in the signed legislation was the ability for the counties to "opt-out" of requiring construction using the unified building code. Several counties have been pursuing this direction. A Building Code Council has been established to administer the code and is in the process of formation.

Alabama
State building code applies only to state buildings, schools, hotels and movie theaters and is based on the 2003 IBC and IRC. Each jurisdiction may adopt different building codes for other types of construction. Legislation to adopt a statewide code failed in the 2006 Legislative Session, but a State Building Commission has been formed to further study the issue. The City of Mobile and some jurisdictions along the coast have adopted the 2000 IRC and IBC and require windborne debris protection. Mobile is currently reviewing the 2003 version of the codes and is planning for adoption late in 2006. Enforcement in the city is only being done for commercial buildings with residential requirements to be enforced with the adoption of the 2003 IRC.

Florida
Windborne debris protection has been required for the entire coastline with the adoption of the 2001 Florida Building Code (FBC) plus legislation that allows protection for only one mile inland for the seven western Panhandle coastal counties. The 2003 IRC and IBC have been incorporated into the 2004 Florida Building Code with numerous amendments. The 2006 Supplement to the 2004 FBC is scheduled to be voted on by the FBC and should go into effect in December 2006.

Governor Jeb Bush has signed Senate Bill 1774 giving authority to the Florida Building Commission to set the windborne debris protection line in the Panhandle. A consultant had been retained by the FBC to provide technical information related to the effects of trees in the area. In a final report, the consultant recommended moving the windborne debris line to the 130 mph contour. The FBC reviewed several other options, but voted in favor of the 130 mph with additional 1,500 feet for land on a bay. This change will go into effect in March 2007.

Relative to windborne debris enforcement, the state has a high compliance, as building officials and the construction industry well understand the threat to the state. This is also backed up with damage assessments after the 2004 and 2005 hurricane seasons that showed structures built after the adoption of the 2001 FBC had withstood the damaging effects of the storm.

Georgia
The state has adopted the 2000 IRC and IBC including the windborne debris provisions for the 120 and 130 mph wind zones. The state is on a six-year code revision cycle and will not adopt the 2003 IRC and IBC. The 2006 version of these codes are being reviewed with expectation of adoption in January 2007. The enforcement of debris protection varies along the coastline.

South Carolina
The South Carolina Building Code Council has adopted the 2003 IRC and IBC; with an effective date of January 2005 for the IBC and July 2005 for the IRC. The 2006 version of these codes are being reviewed with adoption expected by January 2008. The windborne debris residential moratorium was completely eliminated when the 2003 IRC was enforced. The state requires windborne debris protection for the 120 and 130 mph wind zones. Coastal enforcement is very high along the coast and to a lesser degree inland.

North Carolina
The 2000 IRC and IBC are in effect as part of the statewide building code with the 2003 versions to be enforced in January 2007. Windborne debris protection has been a challenging issue for the state for several years. The North Carolina Building Code Council had placed a moratorium on protection with the adoption of the 2000 IRC and IBC. Beginning January 1, 2006, the Council changed position and is requiring a 1,500 ft area from the coast for windborne debris protection. Enforcement is very limited as communities do not see or understand the need for it.

Virginia
Virginia Uniform Statewide Building Code is based on the 2003 IRC and IBC. The state has required one mile of protection from the coast as its coast is in a 100 mph wind zone. It appears that there is limited enforcement of windborne debris protection at this time.

Maryland
The Maryland Building Performance Standards serve as a base for jurisdictions throughout the state, but each jurisdiction can strengthen or weaken the requirements. The Performance Standards use the 2003 IRC and IBC, with the 2006 versions being reviewed and adoption is expected late in 2007. Windborne debris protection would only be required one mile from the coast, as a 110 mph zone exists at shore areas. Enforcement at this time is not being done; only advisory information is being supplied.

Delaware
There is no statewide building code, but each county has defined a building code for use. The coastal area (Sussex county) has adopted the 2003 IRC and IBC and has been enforcing this code since March 2005. A 100 mph wind zone exists at the coast and a mile windborne debris protection is required. The enforcement level appears to be very high at this point.

New Jersey
A statewide building code is being enforced with a 2000 IRC and IBC as the basis. The 2006 version of the codes are being reviewed with adoption planned for early 2007. Windborne debris protection is required one mile from the coast and a 110 mphwind zone exists along the entire shoreline. The enforcement level of this protection appears to be very strong among the many coastal communities.

New York
The 2000 IRC and IBC are the basis for the New York State Building Code. A review of the 2003 IRC and IBC is in progress with adoption expected by January 2007. Windborne debris protection is required as the eastern end of Long Island is in a 120 mph wind zone and the remaining area of the island being in 110 mph zone. Enforcement of this protection appears to vary throughout the area.

Connecticut
The Connecticut State Building Code is in use with the 2003 IRC and IBC being the basis. The effective date was January 2006. Windborne debris protection is required only in the 120 mph wind zone and not in the 100 mph area. The 120 mph area is south of Interstate I-95. Local enforcement of this protection appears to vary throughout the area.

Rhode Island
The 2003 IRC and IBC are the basis for the Rhode Island statewide building code. Adoption of the IRC and IBC provision went into effect in January 2006. Windborne debris protection is required in the 120 and 110 mph wind zones with enforcement varying.

Massachusetts
The state has not adopted any version of the IRC and IBC. The 2003 IRC is being reviewed for one and two story residential structures. Three story buildings would be included in a review of the IBC. The IRC requirements are scheduled to go into effect in late 2006 on a voluntary basis and will become mandatory March 1, 2007. Windborne debris requirements are part of this code and will affect construction one mile from the shore as the state has a 110 mph wind zone at the coastline. The 2003 IBC will be reviewed later this year with adoption possible by late 2007.

Conclusion

The expansion of building code requirements in states along the hurricane-prone Atlantic and Gulf Coasts has generated a growing demand for impact resistant windows, doors, skylights, storefront and curtain wall systems that can resist damage from windborne debris. In response, manufacturers are expanding and adding innovation and variety to their lines of products. While a familiarity regarding the performance of these integrated glazing systems is important to specifiers, an understanding of the special benefits of impact resistant laminated glass is essential for the delivery of safer and more secure buildings.