MIAMI – Fifteen years have passed since Hurricane Andrew reduced houses, businesses and an Air Force Base to piles of matchsticks. Few physical scars remain in South Dade testifying to the ferocious 175 mile per hour winds, that resulted—at the time – in the costliest natural disaster in American history.
However, among the few positive outcomes that could be associated with the August 24, 1992 storm, it would be the commitment by the Miami-Dade County Building Code Compliance Office (BCCO) to assess field damage and advocate for stronger building codes with the most up-to-date technology in order to protect residents and their families.
Many building code provisions and procedures changed after the $26.5 billion hurricane wreaked havoc on Homestead, Florida City and surrounding South Dade communities.
“You can only test scenarios in a laboratory,” said BCCO Director Herminio Gonzalez. “There is no truer test to see how components and structures will hold up than to see the effects of Mother Nature.”
BCCO spearheaded an exhaustive review and supported significant changes to the then effective South Florida Building Code directed at failure investigations, coordination of local and national construction entities and active participation in the Building Code and Product Review Committee, the Board of Rules and Appeals and their various sub-committees.
Those recommendations resulted in the 1994 Edition of the South Florida Building Code. This Edition of that code dictated that building construction be revised to ensure that high wind provisions were adequately established to meet a demonstrated threat. All building envelope components and systems would be verified to be in compliance with the Code by meeting established standards. Where standards did not exist, BCCO developed Testing Protocols for construction products and systems. Only after successfully demonstrating compliance could a Notice of Acceptance for the product, component or system be issued, therefore allowing use in Miami-Dade County.
These enhancements the expansion of the BCCO Product Control Division, which has set the benchmark for product evaluation and approval and has in fact become the recognized leader, nationally, in construction product, system and component approval. Inspectors and Plans Examiners received comprehensive training in the revised post-Andrew building code. They were then required to maintain annual continuing education levels well beyond those required by the State of Florida.
Additional inspections also became required at critical stages of building construction. Testing and Application Protocols were established for various roofing systems.
Many of the provisions of the 1994 South Florida Building Code were later included in the High Velocity Hurricane Zone Volume of the Florida Building Code when the state adopted a single state code in 2002.
“Property-owners must be aware that building codes are only the legal minimum acceptable standard,” said Gonzalez. “We strive for the most stringent requirements possible because this process is like that of a chain; the house can only perform, as well as its weakest part.”
Quick facts about homes built in 1994 or after:
• Newly constructed residences must be equipped with impact resistant glass or hurricane shutters that are approved for use in Miami-Dade County. That means that shutters approved for use from the ground floor to 30 feet elevation, a large missile test must be passed. It consists of a nine-pound, two by four shot at the shutter at 50 feet per second or the equivalent of 34 miles per hour. For shutters placed from 30 feet elevation to roof top, a small missile test is administered, which requires steel ball bearings shot at the shutters at 130 feet per second or 88 miles per hour.
• Thicker plywood (5/8th thickness) is now used in construction. Concrete and masonry reinforcements undergo more stringent requirements.
• All trusses require strap tie-downs with minimum uplift force of 700 pounds.
• Oriented Strand Boards (OSB) are no longer allowed in construction on a house’s second story or roof decking. OSB was widely used in the Country Walk development and almost all second sustained significant damage.
• The Building Envelope of a house is reviewed by structural analysis.
• All components of the Building Envelope (windows, doors, roof tiles, etc.) must have BCCO Product Approval and withstand windloads of 146 mph.
The City of Homestead is one of the cities that underwent major rebuilding and renovation since 1992. After Andrew, much of its population fled leaving behind approximately 26,000 residents behind to rebuild. Fifteen years later, the second-oldest municipality in the County now boasts a population of 57,605 with more than 12,000 residential units being constructed under the more stringent codes during the last seven years.
“Homes built after 1994 have benefited from new methodologies and technology,” said Gonzalez, “however, homeowners should never be complacent during Hurricane Season. Always prepare in advance of a threatening storm.”