Wind-Borne Debris Region in Florida
Where the Florida Building Code requires impact protection on glazed openings, how that differs from the High-Velocity Hurricane Zone, and why a design wind speed is only the first fact.
What a wind-borne debris region is
A design wind speed tells you how hard the wind pushes. A wind-borne debris region tells you something else: in that area, the code expects wind to pick up debris and throw it at the glass. ASCE 7, the standard the 2023 Florida Building Code uses for wind loads, draws the region inside the broader hurricane-prone coast (design wind speeds above 115 mph). Inside it, glazed openings need opening protection.
That protection is impact-resistant glazing, such as impact windows and impact doors, or an approved impact protective system such as shutters or panels. The Florida-licensed PE who seals the wind load calculation, and the building department that reviews the permit, confirm what your address requires.
The two ways an address qualifies
The thresholds use the basic design wind speed for the building's risk category. Homes are Risk Category II. The Florida wind zone map lists those speeds for Miami-Dade, Broward, and Palm Beach.
Within one mile of the coast, at least 130 mph
Locations within one mile of the coastal mean high water line are in the wind-borne debris region when the design wind speed is at least 130 mph. This is the rule that pulls some lower-speed shorelines into the region.
Anywhere the speed is at least 140 mph
Anywhere the design wind speed is at least 140 mph is in the region, including lots miles inland. South Florida's mapped speeds sit well above that line, which is why the beach rule is not the reason Miami-Dade, Broward, and Palm Beach are included.
South Florida: debris region and HVHZ
Risk Category II speeds from the same county table as the wind zone map and the wind load calculator. A county is marked in the wind-borne debris region when every listed speed is at least 140 mph.
| County | Design wind speed | Wind-borne debris region | HVHZ | Product approval accepted |
|---|---|---|---|---|
| Miami-Dade | 175 mph | Yes | Yes | Miami-Dade NOA or a Florida Product Approval approved for HVHZ use |
| Broward | 170 mph | Yes | Yes | Miami-Dade NOA or a Florida Product Approval approved for HVHZ use |
| Palm Beach | 160 to 170 mph, varies by location | Yes | No | Florida Product Approval or Miami-Dade NOA |
Palm Beach County's speed changes by location. Use the county wind speed map linked from the Florida wind zone map when you need the value for one address. Higher risk categories, such as schools and hospitals, use higher mapped speeds, so they remain in the region wherever a house already is.
HVHZ is stricter than the debris region
The High-Velocity Hurricane Zone is Miami-Dade County and Broward County. It lies inside the wind-borne debris region. Glazed openings there still need impact protection, and the product approval has to be valid for HVHZ use: a Miami-Dade Notice of Acceptance, or a Florida Product Approval specifically approved for HVHZ use.
HVHZ testing is Miami-Dade's TAS protocols. TAS 201 is the impact test, TAS 202 is uniform static air pressure, and TAS 203 is cyclic pressure. Outside the HVHZ, including Palm Beach County, opening protection is usually shown with a Florida Product Approval tested to ASTM E1886 and ASTM E1996. An NOA can be used there as well. A product approved for the HVHZ also satisfies the debris-region protection rules. A statewide approval without the HVHZ designation is not enough in Miami-Dade or Broward.
Impact windows and doors
Laminated impact glazing stays in the frame. It protects the opening without a separate panel to close before a storm. The approval has to cover the size, the glass, the frame, and the hardware actually installed.
Shutters and panels
An approved impact protective system can cover the same glazed opening. It counts when it is rated for that opening and deployed. A shutter left open does not protect the glass.
On a house, the glazed openings are within 30 feet of grade, which is the height where the code calls for large-missile protection. Glazing higher on a tower can fall under the small-missile test instead. The product approval states which test the assembly met. The Florida Building Code hub describes those tests and the permit path in more detail.
Why a wind speed map is not a window rating
Homeowners often stop at the mapped speed. The code uses that speed for three separate decisions, and only one of them is "are we in the wind-borne debris region?"
- Region. Compare the speed with 130 mph near the coast and 140 mph everywhere else. That decides whether glazed openings need impact protection at all.
- Exposure. The wind exposure category describes the ground the wind crosses. Exposure C is the usual South Florida neighborhood. Exposure D is open water. Exposure changes the pressure. It does not move the debris-region line.
- Design pressure. Engineers turn the speed into a velocity pressure at the roof, then apply coefficients for wall zone and opening size. The wind load calculator estimates that chain for planning, and the wind speed to psf calculator shows the speed-to-pressure step on its own. The design pressure ratings guide explains how to read the positive and negative numbers on an approval.
An impact-rated product still has to meet the positive and negative design pressure for that specific opening. Being inside the wind-borne debris region answers the impact question. It does not pick the pressure rating, and it does not replace a sealed calculation. The hurricane window ratings guide shows how the pressure rating, the missile test, and the approval read on one product.
What to do next
- Find the county design wind speed on the Florida wind zone map. In Palm Beach, confirm the speed for the address.
- In Miami-Dade or Broward, shop products with an HVHZ approval. In Palm Beach, a Florida Product Approval tested for wind-borne debris is the usual path.
- Cover every glazed opening with impact-resistant glazing or an approved shutter or panel, installed the way the approval describes.
- Estimate each opening's pressures with the wind load calculator, including inland versus shoreline exposure.
- Submit wind load calculations sealed by a Florida-licensed Professional Engineer with the permit, unless the building department accepts an approved county chart for the home.
Wind-borne debris region questions
What is a wind-borne debris region?
In ASCE 7, the wind standard the 2023 Florida Building Code uses, a wind-borne debris region is the part of a hurricane-prone region where wind can drive debris into glazed openings. It includes locations within one mile of the coastal mean high water line where the design wind speed is at least 130 mph, and any location where that speed is at least 140 mph. Glazed openings there need impact-resistant glazing or an approved impact protective system.
Is South Florida in the wind-borne debris region?
Yes for a typical home. Risk Category II design wind speeds are 175 mph in Miami-Dade, 170 mph in Broward, and about 160 to 170 mph in Palm Beach depending on the address. Each of those is at least 140 mph, so the three counties are inside the region, including inland neighborhoods. The one-mile coastal rule is not what puts these counties in the region.
How is the wind-borne debris region different from the HVHZ?
The High-Velocity Hurricane Zone is Miami-Dade and Broward only. Those counties are also in the wind-borne debris region, and the HVHZ adds its own product rules: a Miami-Dade Notice of Acceptance or a Florida Product Approval approved for HVHZ use, tested to TAS 201 (impact), TAS 202 (uniform static pressure), and TAS 203 (cyclic pressure). Palm Beach County is in the wind-borne debris region and outside the HVHZ. A product accepted for HVHZ use also meets the debris-region protection rules. A product accepted only outside the HVHZ may not be permitted in Miami-Dade or Broward.
Do I need impact windows, or are shutters enough?
Either can satisfy the code when the product is approved for that opening and installed the way it was tested. Impact windows and impact doors stay in the frame year-round. Shutters and panels protect the glass when they are deployed before the storm. A house can mix the two. Every glazed opening still needs an approved method.
Why is a design wind speed map not enough to choose a window?
The map gives the design wind speed, which is also how you tell whether the address is in the wind-borne debris region. It does not set the design pressure. Pressure still depends on mean roof height, wind exposure category, the size of the opening, and whether the opening sits in a corner zone. The map also does not say whether a product approval is valid for HVHZ use. A wind load calculator can estimate pressures for planning. The permit still needs pressures sealed by a Florida-licensed Professional Engineer, or a method the building department accepts.
Does a waterfront exposure category put me in the wind-borne debris region?
No. Exposure category describes the terrain the wind crosses before it reaches the house. The debris region follows design wind speed and, near the coast, distance to the water. An inland Miami-Dade lot and a bayfront lot are both in the region. Exposure D can raise the design pressure the product has to be rated for. The engineer who seals the calculation decides the exposure.
Who confirms that my openings meet the wind-borne debris rules?
The Florida-licensed Professional Engineer who seals the wind load calculations, the product approvals submitted with the permit, and the building department that reviews the work. This page is an educational guide, not a sealed calculation. It does not assign approval numbers, design pressures, or permit requirements to a specific house.
Impact products for your county's opening protection
National Glass & Construction quotes impact windows and doors for South Florida homes in the wind-borne debris region, including HVHZ approvals in Miami-Dade and Broward. This site is the guide. The estimate comes from National Glass.