The High Velocity Hurricane Zone
HVHZ is where the strictest wind-load and product-approval rules in the country apply — Miami-Dade and Broward counties, where ultimate design wind speeds typically run ~170–180 mph (Risk Cat II) and vary by site. Those speeds drive the highest wind load pressures in the country.
The four enhanced demands
HVHZ areas face the highest hurricane exposure in the continental U.S. — so the Florida Building Code raises the bar on four fronts.
Extreme Wind Speeds
Ultimate design wind speeds typically ~170–180 mph (ASCE 7-22, Risk Cat II) — higher on the very highest Risk Cat IV coastal maps. Always varies by site.
NOA-Approved Products
Every window, door, shutter and roof assembly needs a Miami-Dade NOA or equivalent certification.
Wind-Borne Debris
Impact-rated glazing or approved shutters on every building — regardless of distance from the coast.
Strict Inspections
Enhanced inspection protocols plus third-party testing verification under FBC enforcement.
What triggers HVHZ designation
Two criteria define an HVHZ area: a wind-speed threshold and statutory coastal designation.
Wind-Speed Criterion
A high-wind region — HVHZ corresponds to the historical wind-speed basis of 130 mph or greater. Today the statutory HVHZ counties carry ASCE 7-22 Risk Cat II design speeds of roughly 170–180 mph, varying by site.
Coastal Proximity
Specific coastal counties designated by the FBC regardless of the wind-speed map.
Where HVHZ rules apply
Florida codifies HVHZ statewide; comparable high-wind coastal provisions govern parts of the Texas Gulf coast and Hawaii.
Miami-Dade County
Entire county is HVHZ — the most stringent rules. Miami-Dade NOA required.
Broward County
Entire county is HVHZ. Broward NOA or Miami-Dade NOA accepted.
Other High-Wind Coast
Portions of Monroe, Palm Beach & Collier may qualify by wind-speed map; the Texas Gulf coast and Hawaii carry comparable high-wind provisions.
Run HVHZ-aware pressures with the Florida Wind Load Calculator →
The key differences
HVHZ is substantially more demanding than standard zones — the provisions an engineer or contractor notices first.
| Requirement | Standard (Non-HVHZ) | HVHZ · Miami-Dade / Broward |
|---|---|---|
| Design wind speed V (Risk Cat II) | ~120–170 mph | ~170–180 mph (varies by site) |
| Product approval | Florida Product Approval (basic) | Miami-Dade NOA / Broward NOA |
| Wind-borne debris protection | Within 1 mi of coast at V ≥ 140 mph | ALL buildings, any distance |
| Impact testing standard | ASTM E1996 / E1886 | Miami-Dade TAS 201 / 202 / 203 |
| Window / door design pressure | Per ASCE 7 wind loads | ASCE 7 + Protocol PA-201/203 |
| Typical residential window DP | DP-30 to DP-50 | DP-50 to DP-80+ |
| Cost premium vs standard | Baseline | +30% to +60% |
| Inspections | Standard dept. inspections | Enhanced + third-party verification |
Miami-Dade NOA & the TAS protocols
A Notice of Acceptance from the Miami-Dade Building Code Compliance Office (BCCO) is the most stringent hurricane-product approval in the U.S.
TAS 201
Impact resistance — large missile, 9 lb 2×4 at 50 fps.
TAS 202
Cyclic pressure testing — 9,000 pressure cycles.
TAS 203
Water resistance after impact & cyclic loading.
Verify NOA status before you buy
Search the BCCO Product Control database by manufacturer, product or NOA number; confirm it is current and active, that your exact model is listed, and review the installation requirements. Expired or invalid NOAs cause permit denial, costly tear-out, denied insurance claims and installer liability.
How high the ratings climb
DP is the maximum wind pressure (psf) a component withstands without failure — tested per ASTM E330 for both positive (push) and negative (suction) loads. HVHZ pushes those ratings far higher.
| Location / Zone | Residential Window DP | Commercial Curtain Wall DP |
|---|---|---|
| Inland Non-HVHZ · V ≈ 120 mph | DP-30 to DP-40 | DP-40 to DP-60 |
| Coastal Non-HVHZ · V ≈ 150 mph | DP-40 to DP-50 | DP-60 to DP-80 |
| HVHZ · V ≈ 170–180 mph (Risk II) | DP-50 to DP-70 | DP-80 to DP-100 |
| HVHZ · highest Risk IV coastal map (≈ 195 mph) | DP-70 to DP-90+ | DP-100 to DP-150+ |
HVHZ residential window in Miami Beach
Single-family home in Miami-Dade County HVHZ — corner wall zone, worst case.
Inputs
The math
qh = 0.00256 · Kh · Kd · V² qh = 0.00256 · 1.12 · 0.85 · 175² qh = 74.6 psf p = qh · G · Cp (G = 0.85) Zone 4 corner: Cp = −1.6 p = −101 psf (suction) p = +63 psf (pressure)
Required rating must exceed ±101 psf → specify DP-55 or higher.
Selection: impact-rated aluminum window, Miami-Dade NOA, DP-110, tested per TAS 201/202/203.
Six rules that keep HVHZ projects compliant
Compliance lives in the details — product selection, exact installation, and documentation.
1 · Verify NOAs Early
Check status for every product before ordering — via the official BCCO database, not a sales rep.
2 · Follow NOA Drawings
Match approved details exactly. Wrong fastener spacing or anchors voids the approval.
3 · Document Everything
Keep NOA letters, product labels, install photos and inspection reports on file.
4 · Third-Party Inspections
Coordinate inspection agencies early — HVHZ adds reviews beyond the building department.
5 · Use Certified Installers
Many products require manufacturer-certified technicians — verify credentials first.
6 · Plan for Higher Costs
Budget +30–60% for HVHZ products. Impact windows can run $100–$200+ per sf installed.
Common compliance mistakes to avoid
Skip the protocols. Run the pressures.
Our sister site WindLoadCalc.com automates HVHZ design pressures — Miami-Dade and Broward wind-speed lookup, latest ASCE 7-22 C&C calculations, DP recommendations and NOA compliance checks.