The High Velocity Hurricane Zone (or HVHZ) in Florida encompasses only Miami-Dade And Broward Counties. It is a special section of the Florida Building Code (2017 FBC as of this writing) which lays out special codes which apply to these counties.
Many chapters of the Florida Code offer an HVHZ and non-HVHZ section of the code. Most (but not all) sections of the HVHZ are more stringent than non-HVHZ.
The Florida Product Approval System also separates approved products by outside and/or inside the HVHZ.
We recommend reviewing applicable sections of the Florida Building Code before designing and constructing in Florida. If at all in doubt, Engineering Express is here to help. Use our Live Chat feature for quickest response.