Window Wind Load

Window & Door Design Pressure Ratings Explained

Design pressure (DP) is the measure of a window or door's structural performance, rated in pounds per square foot (psf). It represents the maximum wind pressure the product can withstand without failure.

Positive vs. Negative Pressure

Positive Pressure (+psf) - Inward-acting pressure on the windward side of the building.
Negative Pressure (-psf) - Outward-acting suction on the leeward side and at corners. Typically larger than positive pressures.

Wall Zones

Zone 4 (Interior) - Majority of wall surface. Lower wind pressures.
Zone 5 (Corner) - Near building corners where wind accelerates. Higher pressures.

Common Design Pressure Ratings

DP Rating	Typical Use	Suitable For
DP 35-40	Basic residential	North FL inland, Zone 4
DP 45-50	Standard residential	Central FL, moderate zones
DP 55-65	Coastal residential	Coastal areas, Zone 5
DP 70+	High-performance	HVHZ, high-rise, severe coastal

Florida Product Approval vs. Miami-Dade NOA

Florida Product Approval (FL#) - Valid statewide except HVHZ.
Miami-Dade NOA - Required in HVHZ. Also accepted throughout rest of Florida.

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