Florida Building Code: HVHZ Impact Window Requirements
Understanding Florida's High-Velocity Hurricane Zone (HVHZ) building code requirements for impact windows. What homeowners need to know about NOA approvals and compliance.
Florida's building code is one of the strictest in the world when it comes to hurricane protection. If your home is in the High-Velocity Hurricane Zone (HVHZ), you need impact-rated windows — no exceptions.
What Is the HVHZ?
The High-Velocity Hurricane Zone covers all of Miami-Dade County and coastal parts of Broward County. This zone requires the highest levels of wind and impact resistance because it faces the most direct hurricane threats.
The NOA Requirement
Every impact product installed in the HVHZ must have a Notice of Acceptance (NOA) from Miami-Dade County's Product Control Division. The NOA number proves the product has been independently tested and approved for use in the HVHZ.
An NOA certifies:
- Large Missile Impact: Product withstands a 9-pound 2x4 lumber striking at 50 fps
- Cyclic Pressure: Product survives 9,000 cycles of positive and negative pressure
- Water Infiltration: No water leaks under driving rain conditions
- Air Infiltration: Meets maximum allowable air leakage rates
Design Pressure Requirements
Design pressure (DP) measures the wind load a window can withstand, measured in pounds per square foot (PSF). Requirements vary by:
- Building height: Taller buildings need higher DP ratings
- Exposure category: Coastal locations require higher ratings
- Window size: Larger windows need higher DP ratings
Typical requirements for a 1-2 story home in the HVHZ:
- Positive pressure: +40 to +60 PSF
- Negative pressure: -50 to -80 PSF
What Happens if You Don't Comply?
Installing non-compliant windows in the HVHZ can result in:
- Failed building inspection: Your permit will not close
- Insurance denial: Carriers require HVHZ compliance
- Liability exposure: If a window fails in a storm, you're personally liable
- Resale problems: Future buyers' inspectors will flag non-compliant windows
The FBC (Non-HVHZ) Requirements
Outside the HVHZ (most of Palm Beach County, the Florida Gulf Coast), the Florida Building Code (FBC) still requires impact-rated or shutter-protected openings, but the testing standards are slightly less stringent than the HVHZ NOA requirements.
Not sure if your home is in the HVHZ? Contact Izoah — our jurisdiction lookup tool will tell you instantly what your property requires.