During those horrid hurricane seasons of 2004 and 2005, the Texas Gulf Coast remained comparatively unscathed—except for a glancing blow from Hurricane Rita on September 24, 2005. Then came September 13, 2008, and Ike, a large Category 2 storm but with a Category 5 class storm surge, later termed “the most destructive hurricane to ever hit Texas.” If there ever was any residual complacency about hurricane-resistant building codes in those parts (compared to, say, in storm-ravaged Florida), there would be no more.

The Texas Windstorm Insurance Association (TWIA) is the “Insurer of Last Resort”—the state’s wind and hail insurance catastrophe pool. They provide windstorm and hail insurance for structures located in designated catastrophe areas along the Texas Gulf Coast. But, it is the Texas Department of Insurance (TDI) that is tasked with certifying to the TWIA that structures are insurable against windstorm and hail losses, providing inspection services and evaluating building products for compliance with adopted building specifications. As of January 1, 2008, TDI adopted the 2006 IRC and IBC with Texas Revisions.

Dr. Paul Bove, TDI Engineering Services Program Engineer, filled in Southeast Region Meeting attendees about the process of getting fenestration products accepted for use in the designated catastrophe areas. To be eligible for windstorm and hail insurance coverage through the TWIA, new construction, alterations, repairs and additions must be located in a “designated catastrophe area” and constructed and inspected for compliance with the TDI adopted building specifications. This catastrophe area is comprised of the 14 counties that are immediately adjacent to the Texas Gulf Coast plus several cities located in Harris County (Houston). This designated catastrophe area is divided into three zones, each with design wind speeds defined using the wind speed map in the 2006 IRC/IBC and ASCE 7-05. They are:

• Inland II - 110 mph 3-second gust design wind speed
• Inland I - 120 mph 3-second gust. The delineation between Inland II and Inland I is formed by roadways and city limits.
• Seaward - 130 mph 3-second gust. The delineation between Inland I and Seaward is the Intracoastal Waterway.

One of the Texas Revisions to the 2006 IRC/IBC is found in the definition of “Wind-borne Debris Region.” The I-codes define it as “areas 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 or greater…” For TDI and TWIA purposes, windborne debris protection is not required within the Inland II Zone; however, windborne debris protection is required for all exterior glazed openings within the Inland I Zone and windborne debris protection is required for all exterior openings in the Seaward Zone.

Product performance requirements for TDI acceptance are:

• AAMA/WDMA/CSA 101/I.S.2/A440-05 for windows, sliding glass doors, hinged doors, and skylights.ASTM E330 is permitted as an option for hinged doors. Products must bear a label showing compliance with these performance criteria, plus identification of the manufacturer, the performance characteristics, and the name of the inspection agency.

Mullions between windows and glass doors may optionally be tested at a laboratory in accordance with Section R613.9 of the IRC (which references AAMA 450) or engineered (analyzed) in accordance with Section R613.9 of the IRC.

• In addition, impact resistance requirements include testing and conformance with:
  • ASTM E1886, ASTM E1996
  • AAMA 506
  • Reference: Section R301.2.1.2 IRC
  • Section 1609.1.2 IBC
  • Texas Revisions to the 2006 IRC and 2006 IBC