What is High-Velocity Hurricane Zone (HVHZ)?

What is a High-Velocity Hurricane Zone (HVHZ)?

South Florida typically experiences severe tropical storms also known as Hurricanes. However, some areas feel the impact more. These areas are designated HVHZ (High-Velocity Hurricane Zone.) The HVHZ designation aims to ensure the safety and resilience of buildings in South Florida’s most hurricane-prone areas. It helps protect homes and businesses from the damaging effects of severe tropical storms, safeguarding lives and reducing property damage during these powerful weather events.

What is HVHZ?

The High-Velocity Hurricane Zone is an area in South Florida marked for its severe weather. The Florida Building Code applies it to Miami-Dade and Broward counties, which are built to its strictest wind standards. This designation mandates strict building standards to enhance structural resilience and protect lives.

Hurricanes are severe tropical storms with winds of at least 74 miles per hour. This weather condition forms over warm ocean waters to produce a large swirl of storms and pushes a wall of water on dry land causing a flood. 

At 38 mph, it is called a tropical depression. As the winds grow higher to exceed 39mph, it becomes a tropical storm and eventually reaches a hurricane at 74 miles per hour.. 

Hurricanes draw their energy from warm ocean water, and conditions such as wind shear and dry Saharan dust can strengthen or weaken them. The National Weather Service or local Hurricane Center broadcast a looming hurricane. 

This broadcast helps locals prepare for the challenging days ahead. Depending on the predicted damage, some locals may be advised to evacuate their homes. 

Areas Mostly Affected in South Florida

The Atlantic hurricane season runs from June 1 to November 30. The HVHZ covers Miami-Dade and Broward counties; if your property is in either county, you are in the HVHZ. Palm Beach County is not in the HVHZ, although it still has high design wind speeds. Living in the HVHZ means that residents need to be particularly prepared and aware during this period as they are more likely to be impacted by severe weather events. 

Recent Hurricanes in Florida

Hurricane Andrew (1992) and Hurricane Irma (2017) are two of the storms that shaped Florida’s building rules. Hurricane Andrew led directly to the HVHZ provisions; more recent storms include Ian (2022), Idalia (2023), and Helene and Milton (2024). 

Andrew, a category 5 hurricane, had landfall on August 24, 1992, while Irma, a category 4 and later a 3, was on September 10, 2017. Andrew destroyed more than 25,000 homes in Miami-Dade; Irma made landfall in the Florida Keys as a Category 4 and again at Marco Island as a Category 3, causing damage across much of the state. 

How Does HVHZ Affect You?

Living in the HVHZ means that your living conditions must adhere to HVHZ ratings. This rating starts with your building materials. 

Many homes are submerged in flood alongside animals and other valuables when hurricanes hit a community. Some lives are lost while others are left homeless. For this reason, the state has enforced a stricter building code with HVHZ ratings to help reduce the damage caused by hurricanes in these areas. 

Building materials are therefore tested and certified to withstand severe weather conditions.

Miami-Dade NOA and Florida Product Approval

Inside the HVHZ, roofing products must be approved for HVHZ use. That approval is typically shown by a Miami-Dade County Notice of Acceptance (NOA) or by a Florida Product Approval that carries an HVHZ designation. A statewide approval without the HVHZ designation is not enough in Miami-Dade or Broward.

A Notice of Acceptance is issued by the Product Control Section of Miami-Dade County’s Department of Regulatory and Economic Resources, which reviews and approves or denies building-envelope products, including roofing, windows, doors and shutters. HVHZ products are tested to the Florida Building Code’s own Testing Application Standards (TAS), for example TAS 101 for how roof tiles resist uplift and TAS 103 and TAS 104 for tile underlayments. See Miami-Dade’s product approval program.

A Florida Product Approval is the statewide system run by the Florida Building Commission. Each approval has its own FL number, and the listing shows whether the product is approved for use in the HVHZ. Published Miami-Dade NOAs say they are accepted for use in Miami-Dade County and in other areas where the local building official allows them.

An NOA number looks like 22-0714.11, and every NOA has an approval date and an expiration date. Approvals cover a whole system, not one product: the deck type, fasteners, underlayment, roof covering and installation method are approved together, so swapping one component can take the roof outside its approval and fail inspection.

The approval numbers are listed on the roofing permit, and you can look them up yourself on the Miami-Dade Product Control search and the Florida product approval search on floridabuilding.org. Your building department decides what is accepted at your address.

How to Prepare Your Home for Hurricane

Knowing your risk zone outside and within your home helps you prepare for hurricanes. Your building exposure determines the impact rating of the products you are allowed to use and these materials must come with the approved rating markings. 

The following are some tips to help prepare your home for hurricanes in Florida

1. Protect your Roof

Inspect your roof for leaks, gaps, and missing shingles and repair or replace them. For an extra layer of protection, consider roofing straps. Hurricane straps tie the roof framing to the walls, so strong winds are less likely to lift the roof structure off the house. They do not hold down shingles or tiles: the roof covering stays on through its own approved fastening.

You can also ask your contractor which roofing products carry a Miami-Dade Notice of Acceptance (NOA) or Florida product approval for use in the HVHZ. 

2. Secure Windows

Storm shutters will come in handy, providing a sturdy barrier against the battering winds and debris that can accompany a powerful storm. They not only shield your windows from potential damage but also help maintain the integrity of your home’s interior by preventing dust and dirt from being swept in by the gusts. For added protection, considering the installation of impact-resistant glass is a wise choice. This specially designed glass can withstand the force of flying objects during a storm, reducing the risk of shattered windows and maintaining a secure environment for your family and belongings.

3. Trim Trees 

This is perhaps the best time to go around your yard and inspect your trees. Look out for weak and hanging limbs and prune them. Collect fruits and trim shoots. 

If you find a weak tree that may be uprooted when the hurricane starts, it’s better to have it removed than leave it to destroy your home or your neighbor’s. 

Remove abnormally leaning trees and trees with decaying roots. Tree experts have the best tips when it comes to preparing your yard for hurricanes. 

4. Repair Garage Door

Get rid of a faulty garage door or repair it as necessary. Ensure the security of your possessions in your garage until the hurricane has passed. Avoid exposing your vehicle, furnishings, and other portable items to the elements. It is crucial to eliminate any objects that could potentially become projectiles during the hurricane.

5. Backup Generator

The chances of power disruption during the hurricane season are high. If you can afford one, consider a generator that can power up the basic home equipment. However, you must also put measures in place to keep your family safe from any potential generator risks. This includes ensuring proper ventilation to prevent carbon monoxide buildup, keeping the generator away from flammable materials, and regularly inspecting the equipment for any signs of wear or damage.

HVHZ questions homeowners ask

Which Florida counties are in the HVHZ?

Only Miami-Dade and Broward. The High-Velocity Hurricane Zone covers both counties entirely, not just the coast. Palm Beach County is not in the HVHZ, although it still has high design wind speeds.

What is a Miami-Dade NOA?

A Notice of Acceptance (NOA) is Miami-Dade County’s approval for a building-envelope product such as a roof system, window or door. The county’s Product Control Section issues it after the product has been tested and reviewed. Every NOA has an approval date and an expiration date, and you can look it up on the Miami-Dade Product Control search.

Is a Florida Product Approval the same as an NOA?

No. A Florida Product Approval comes from the statewide system run by the Florida Building Commission, while an NOA comes from Miami-Dade County. In Miami-Dade and Broward, a roofing product needs approval for HVHZ use: a Miami-Dade NOA or a Florida Product Approval that carries the HVHZ designation.

How can I check the roofing products on my permit?

Ask your roofer for the NOA or Florida Product Approval numbers listed on the permit, then look them up on the Miami-Dade Product Control search or on floridabuilding.org. Check that each approval is current and that the approved system matches your roof deck and roof type. Your building department is the authority for your address.

Takeaway

Residing in a High-Velocity Hurricane Zone is not a pleasant experience, especially during the exposure period. However, if you have no plans of relocating outside South Florida, your best bet is to prepare for the bad days, by protecting your home and reducing impacts. 

In the heart of the High-Velocity Hurricane Zone, Perkins Roofing Corp stands as your reliable partner for roofing services. Contact us today for expert roof contractors you can trust.