What Is the HVHZ? Miami-Dade and Broward's High-Velocity Hurricane Zone Explained

The short answer: the High-Velocity Hurricane Zone (HVHZ) is a section of the Florida Building Code that applies only to Miami-Dade and Broward counties. Products installed there must meet a stricter approval and testing standard than products used elsewhere in Florida. A window that is perfectly legal in Orlando can fail inspection in Hialeah.

Why the HVHZ exists

The HVHZ came out of Hurricane Andrew in 1992. Investigators found that a great deal of the catastrophic damage was not caused by wind alone, but by wind-borne debris breaking a window or door. Once an opening fails, the house pressurises from the inside, and that internal pressure is what lifts roofs and pushes out walls.

The response was to treat openings as structural. In the HVHZ, a window is not just a window. It is part of the building envelope, and it has to be proven to survive an impact and then hold up under hours of pressure cycling.

Which areas are in the HVHZ

Only two counties: Miami-Dade and Broward. Everything from Hialeah and Miami down through Homestead, and everything from Hollywood up through Deerfield Beach, falls inside it.

Palm Beach, Martin and St. Lucie counties are outside the HVHZ. They still require impact-rated or otherwise protected openings under the Florida Building Code, and coastal design pressures there can be very high, but the approval pathway is different.

This is the single most common point of confusion we run into. Homeowners in Boca Raton sometimes assume they need Miami-Dade NOA products, and homeowners in Miami sometimes get quoted products that are approved for Florida but not for the HVHZ.

NOA versus Florida Product Approval

There are two approval systems, and the difference matters.

Florida Product Approval is the statewide system. A product tested to the relevant standards receives a statewide approval number and can be used anywhere in Florida that its design pressure rating covers.

Miami-Dade Notice of Acceptance (NOA) is issued by Miami-Dade County's Product Control Section. It is the approval required inside the HVHZ, and it involves testing to Miami-Dade's own protocols rather than only the national ones. Because the NOA is the stricter of the two, NOA-approved products are widely used outside the HVHZ as well, and are often treated as a general marker of quality.

We cover the NOA in more detail in What Is Miami-Dade NOA Approval for Impact Windows?

What HVHZ testing actually involves

Products destined for the HVHZ are tested under Miami-Dade's Testing Application Standards, usually referred to as TAS:

TAS 201 — Impact. The product is struck with a wind-borne debris missile. For openings in the lower portion of a building, that missile is a length of dimensional lumber fired at the glass. For higher openings, it is a spray of small steel spheres at much higher velocity.

TAS 202 — Uniform static air pressure. The product is loaded to its rated positive and negative design pressure and has to hold without failing.

TAS 203 — Cyclic wind pressure. This is the one people underestimate. After being hit, the already-damaged unit is put through thousands of pressure cycles that simulate the hours of buffeting that follow the initial debris strike. Plenty of assemblies survive the impact and then fail here.

That sequence is the point. A product does not pass by surviving a single hit. It passes by surviving the hit and then the storm that follows it.

Design pressure is address-specific

HVHZ approval is necessary but not sufficient. Each opening also needs a design pressure rating appropriate to your specific building — and that depends on wind speed for your location, the height of the opening, how exposed the site is, and where the opening sits on the wall. Corners and gable ends see higher loads than the middle of a wall.

This is why a serious quote is written after someone measures at your address rather than over the phone. A barrier-island home in Sunny Isles Beach and an inland home in Doral can need materially different products even though both are inside the HVHZ.

What to ask before you sign

Three questions will tell you most of what you need to know about a quote:

1. Is this product NOA-approved, and what is the NOA number? If your home is in Miami-Dade or Broward, the answer needs to be yes, and the number should be verifiable.

2. What design pressure is each opening rated for? A quote that lists one rating for the whole house has probably not been engineered per opening.

3. Who pulls the permit? HVHZ permitting requires the approval documentation to be submitted with the application. If a contractor asks you to pull an owner-builder permit, you are taking on the liability.

Getting it right the first time

We install products carrying both Florida Product Approval and, where the HVHZ requires it, Miami-Dade NOA — including Mr. Glass and Eco Window Systems. We measure every opening individually, specify to that opening, and file the approval paperwork with the permit ourselves.

If you want to know exactly which approval pathway applies at your address, get a free measurement and written quote or call (561) 464-6272.

FL License #CGC1530499 • In-house W-2 crews • Fixed-price written quotes • Permits pulled directly with your local building department.