Florida is the most hurricane prone area of the United States: every hurricane season more tropical systems and cyclones make landfall in Florida than anywhere else in the United States. These storms range in severity from what are effectively just really nasty thunderstorms, to dangerous city-leveling superstorms that can cause billions of dollars of damage. To help mitigate this massive environmental threat, some counties and municipalities enact their own special set of building codes and regulations to ensure buildings are more resilient to hurricanes. Miami-Dade county in particular is known for being at the forefront of these efforts and is nationally recognized for their rigorous hurricane certification standards – often referred to as the Miami-Dade certification.
The Miami-Dade certification as we know it today has been a continually evolving effort developed in response to Hurricane Andrew, which wreaked havoc all over South Florida and the Bahamas in 1992. In total, Andrew is believed to be responsible for over $25 billion in damages, $45 billion adjusted for inflation. Post-hoc analyses of Andrew’s devastation determined that its severity was in part catalyzed by the shoddy building construction in the Miami-Dade area that proliferated the region as it attempted to accommodate the massive population influx that occurred throughout the ‘80s and into the early ‘90s.
All-in-all, the Miami-Dade certification involves lots of aspects of the building and construction industry – from people and practices, to materials and project management. One of the most important aspects of the Miami-Dade certification is the requirement that certain building materials meet its rigorous standards. Specifically, §8-40 of the Miami-Dade County Code of Ordinances prescribes that: “materials/products used for protection of the envelope of the structure, limited to windows, exterior glazing, wall cladding, roofing, exterior doors, skylights, glass block, siding and shutters shall obtain a high wind velocity zone approval from the Florida Building Commission.” This means that any project, commercial or residential, within Florida’s pre-defined High Velocity Hurricane Zone (HVHZ), which includes all of Miami-Dade and Broward counties, must use materials and employ practices that conform to this standard. Additionally, although the standard is not compulsory outside of these counties, some builders do follow it due to its high regard within the building community.
This certification is so well outlined that it even designates products as either being approved or not approved for use within the HVHZ. A product is typically viewed as something sold by a manufacturer or distributors in a discrete unit for use by a builder. This means that in the case of rainscreens and other external cladding systems, the system as a whole sold by a manufacturer or distributor would need to be approved for use in the HVHZ. In order to receive approval, a manufacturer must submit their product for testing to demonstrate that it meets relevant wind resistance and strength standards. Depending on the product this will often include sending it to a pre-approved laboratory for testing . When a product is approved it receives a Notice of Acceptance (NOA) and is also subject to periodic Quality Assurance reviews to confirm its still performs as it did when the NOA was first issued. Additionally, manufacturers or fabricators of more expendable single use products can also be issued a Certificate of Competency after demonstrating they produce their products in accordance with county regulations. See the flowchart below for a full picture of the approval process.
Is the Miami-Dade certification the future of hurricane certification nationwide? Well – yes and no. As mentioned, the certification is recognized and accepted for its rigor outside of HVHZ counties, for example regulators and builders in Hawaii, Japan, South America, Guam and the Caribbean have all taken it as proxy for local standards. Yet, the standard is also extremely rigorous and recognized in these areas because they are regions most prone to hurricanes, typhoons, and other major tropical storms on the planet. In other words, in many places the rigor of the Miami-Dade certification could rightly be thought of as overkill and put an unnecessary burden on builders and property owners because the statistical risk of major wind storms is significantly lower. Nonetheless, the frequency of severe storms has been increasing at an alarming rate and more and more parts of the country are beginning to be viewed as at-risk for being impacted by hurricanes and other high-wind tropical storms. So overall, the spread of the Miami-Dade standard will likely depend on whether or not this disturbing increase in severe storms continues.