Mother Nature has met her Match

While no single product offers complete protection from hurricanes, typhoons and violent storms, laminated glass windows and doors made with Saflex® , Saflex HP or Saflex® Storm protective interlayers can be a critical first line of defense.

In properly designed systems, laminated glass effectively withstands these natural forces to help maintain the critical exterior envelope. If broken by impact from wind-borne debris, the glass fragments bond firmly to the protective interlayer, continuing to safeguard building occupants and contents.

Protecting the Building Envelope
Meeting Hurricane Codes and Standards
Where the Standards are Applied
Designing Impact Systems
Designing for Essential Facilities: Level E Protection
Additional Benefits of Laminated Glass

Protecting the Building Envelope
Under normal circumstances, buildings are designed to allow wind to flow over the structure. During a hurricane, a fully intact building envelope or "outer skin" allows wind to flow at, over and past the structure without damage. Preventing a breach in the building envelop, therefore, is among the most important steps to maintaining the integrity of the structure and ensuring non-destructive windflow during hurricane-force winds.

During the sustained, high-speed winds of a hurricane, debris can be lifted and become an airborne missile or wind-borne debris. Large missiles, such as roof shingles and other construction materials, are common at heights up to 30 ft. (9 m) above grade; small missiles, such as roof gravel, are most prevalent at heights above 30 ft. (9m).

When wind-borne debris breaks glass windows and doors, the building's protective exterior "envelope" is compromised, allowing strong winds to rush into the structure. These trapped wind forces then exert upward pressure on the roof and outward pressure on exterior walls, and can eventually cause total destruction.

Laminated glass with Saflex interlayer in properly designed windows and doors can withstand the damaging impact of wind-borne debris and remain in the opening during hurricane-force winds because the glass will stay intact even if cracked.

Meeting Hurricane Codes and Standards
In order to meet hurricane building codes, commercial and residential window and door systems have to meet vigorous impact, wind-borne debris and cyclic pressure test standards. Test procedures call for the entire system to resist wind-borne debris impact followed by pressure cycling. To comply with the test requirements for an impact-resistant product, the systems may also need to pass additional tests such as air and water infiltration, structural load and forced-entry resistance.

Properly designed laminated glazing systems made with Saflex® , Saflex HP or Saflex® Storm interlayers perform well during large missile impacts and cycling. When focusing on the use of laminated glass, it is crucial to understand the importance of the overall system design including:

  • Glass size of the window or door opening
  • Glazing materials thickness and composition
  • Framing component design
  • Glazing installation within the frame

Solutia's interlayers are commonly found in windows and doors that meet the newest and most stringent hurricane resistant codes, state approval programs and testing standards including:

  • Model building codes such as International Building and Residential Codes (IBC and IRC)
  • State product approval programs including Florida Building Code (FBC) and the Texas Department of Insurance (TDI)
  • Relevant testing protocols and standards including Dade County TAS 201, 202 and 203, ASTM E1886, ASTM E 1996 and SSTD 12
Missile Type and Wind Zone

Where the Standards are Applied
The map below indicates the wind speeds in the ASCE 7 (need year) standard that tend to govern the design pressure needed for a window or door system. ASTM International has a test method (ASTM E1886) and a corresponding specification(ASTM E 1996), that instructs how to perform the test and indicates what missile and speed shall be used depending upon application and wind zone, location, pass/fail criteria and substitution limitations for the project. For example, below 30 feet from grade is typically the zone for impact by a timber (large missile), whereas above 30 feet from grade is the zone for impact by 2 gram steel ball bearings (small missile).

Designing Impact Systems
When designing hurricane-resistant window and door systems, the key elements are the framing system, laminated glass, anchoring and sealant. All must work together to withstand structural, impact and cycling loads. Different interlayers and thicknesses have a direct effect on the performance during impact and cycling loads. As with the qualification of any system, no single variable independently affects the outcome. The performance of the system depends upon the factors working together.

As shown in the following chart, different interlayers are recommended based on basic window type, average glass size, geometry, and design pressure. For instance, a typical large missile system (or window system below 30 ft.) utilizes laminated glass with an interlayer that is 0.090 in. in thickness, with specialty interlayers available with composite technology that can be thinner (Saflex Storm 0.075 in. thick). A typical small missile system (or window system above 30 ft.) utilizes laminated glass with an interlayer that is 0.060 in. in thickness.

Designing for Essential Facilities: Level E Protection
While most hurricane-related building codes are designed to protect homes and businesses during a hurricane, experts still advise people to evacuate. A tough performance standard known as ASTM E1996 "Level E" was designed to protect buildings and the people inside when evacuation is not an option. However, until now, there were few solutions available for achieving Level E. Those that were available were so costly that they were often value-engineered out of the plans.

In early 2008, Saflex introduced a hurricane interlayer system that can meet Level E in a single piece of laminated glazing. The new Saflex® Level E hurricane solution uses a combination of Saflex's most powerful interlayers, laminated between two pieces of glass under heat and pressure. The resulting piece of glass looks and functions like a single piece of ordinary glass but is stronger and tougher than even standard laminated glass. It's convenient and cost-effective for architects and building owners who demand the highest level of protection.

Download Structural Building Code Websites By State

Additional Benefits of Laminated Glass

For more information on Saflex or Vanceva interlayer, contact us.

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