Storm & Security

CODE/UPDATE | by Joseph D. Belcher | What Have They Done to Wind Zone 4? Good intentions, a glitch and changes to be submitted. I can alreadyZone 4?!?���it now: hear ���What the heck is Wind For businesses in the hurricane protection industry not operating in Miami-Dade County, FL, this may be a new term. Simply put, Wind Zone 4 is a convention created to apply to Miami-Dade County, which due to changes to the 2012 International Codes now will apply to a much larger area. The change has been felt first in Florida because Florida adopted ASCE 7-10 in the 2010 Florida Building Code rather than waiting for the publication of the 2012 International Building Code. For parts of the country outside of Florida this will not be an issue until jurisdictions begin adopting the 2012 International Building Code. In an effort to correlate the wind speeds of ASCE 7-10 with the Wind Zones of ASTM E 1996, changes were made to ASTM E 1996 within the International Codes. The changes were made without consulting the ASTM committee responsible for the specification (ASTM Committee E06). While the proponent of the change has stated there was no intent to expand Wind Zone 4, the changes do in fact expand Wind Zone 4 considerably. The assertion brings to mind an old saw related to paths to certain undesirable locations being paved with good intentions. What at one time applied solely to Miami-Dade County now applies to Lee, Collier, Palm Beach, Martin, Saint Lucie, Broward, and Monroe counties. Other states will be affected by the changes with the adoption of the 2012 International Codes. The provisions have generated considerable controversy in Florida, the most impacted region, but any area with a basic wind speed of greater than 160 mph per ASCE 7-2010 is impacted as well, and might be affected with the adoption of the 2012 International Codes. Unfortunately, the proponent of the change was not aware of the impact of the change and its unintended consequences. Correcting the Glitch The ASTM Wind Zone 4 is defined by ASTM as areas with a wind speed of greater than 140 mph and was intended to apply solely to Miami-Dade County. The attempt to correlate the wind speeds of ASCE 7-10 and the wind zones of ASTM 1996 simply added a provision within the International Codes changing ASTM E 1996 by increasing the ASTM Wind Zone defined wind speeds by 20 mph. The change results in a much larger Wind Zone 4. The International Hurricane Protection Association (IHPA) was able to correct this in the 2010 Florida Building Code through a glitch change proposal to increase the ���greater than 160 mph��� to ���greater than 170 mph.��� The Florida Building Commission agreed and the change was accepted for the 2010 Florida Building Code 10 STORM & SECURITY PROTECTION / IBS PREVIEW 2013 Supplement. There is a multitude of evidence this is the correct number and the ASTM E06 Committee is considering updating the Standard as this column is being written. While the greatest impact of the changes is felt in Florida, companies manufacturing, distributing, selling and installing impact protective systems, including impact resistant windows, need to be aware of the newly expanded zone. Simply re-stated, products for use in Wind Zone 4 are subject to provisions similar to those required in Florida Test Protocols for High Velocity Hurricane Zones (HVHZ)���a/k/a Testing Application Standards (TAS)���of the Florida Building Code. For Wind Zone 4 the ASTM Standard calls for two strikes per specimen; contains different impact site provisions for mullions, meetings or checkrails, and meeting stiles; and applies more stringent deflection criteria. The provisions in the ASTM Standard, however, are not mandatory unless the specifying authority applies them. Why Wind Zone 4 Was Created Earlier versions of the Standard defined three wind zones primarily for use in the missile selection for a given region. The specifying authority is charged with selecting an applicable missile by selecting, among other things, a wind zone as defined by the Standard. Wind Zone 4 first appeared in the 2002 Edition of ASTM E 1996 and originally was an effort to encourage Miami-Dade County to adopt the Standard. Minutes of the meetings of ASTM Committee E06 from the time indicate the intent was to create a wind zone acceptable for use in Miami-Dade County. The effort to create the wind zone was initiated at the request of the IHPA in an effort to get Miami-Dade County to adopt ASTM Standards in lieu of the locally developed standards. IHPA���s intent was to have one standard for its members to live and do business under. IHPA���s desire was to address the existence of multiple standards affecting the business of its members. The idea was to incorporate the more stringent provisions adopted by Miami-Dade County by adopting them into the ASTM Standard, thereby encouraging the adoption of ASTM E 1996 by Miami-Dade County. The Florida Test Protocols for High Velocity Hurricane Zones (TAS 201 and 203, a/k/a Miami-Dade County Testing Application Standards) are more stringent than those of ASTM E 1996 Wind Zones 1, 2 and 3. In response, ASTM created Wind Zone 4 in ASTM E 1996 to incorporate the Miami-Dade Standards and allow the use of ASTM E 1996 in Miami-Dade County. The wind speed trigger of greater than 140 mph was selected to limit the application to Miami-Dade County. The problems with the economy resulted in Miami-Dade personnel withdrawing from the ASTM E06 Committee, and the changes did not result in the adoption of the Standard by Miami-Dade County.

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