Design Pressure Estimator

Windows & doors — ASCE 7 components & cladding method · Majestic Permits
Estimation tool only — not for permit submission. This uses simplified, approximate coefficient values to give a ballpark design pressure. Actual permit-ready calculations must be performed with the official ASCE 7 tables/figures (or engineering software) and sealed by a Florida-licensed engineer. For product selection, match against the window/door's tested DP rating on its Miami-Dade NOA, Broward BC approval, or Florida Product Approval — don't install based on this number alone.

Site & Building Inputs

From ASCE 7 wind speed map for the site — HVHZ (Miami-Dade/Broward) often 170–175 mph for Risk Category II.
1.0 for typical flat sites; higher near hills/escarpments/ridges (rare in most of FL).
0.85 is the standard ASCE 7 value for components & cladding.
Product NOA/FPA "DP" ratings are conventionally stated at ASD level (≈0.6× strength-level pressure). Use ASD to compare against a product's rated DP.

Opening Inputs

Most finished homes/buildings are "enclosed."
Corner-zone openings see higher suction than field-of-wall openings.
Roughly the opening's area — smaller openings see higher localized pressure.
Velocity Pressure qz
psf
Kz (interpolated)
unitless
Positive DP (inward)
psf
Negative DP (outward)
psf
Estimated Product Rating Needed
psf, rounded up to nearest 5

Calculation Trace

qz = 0.00256 × Kz × Kzt × Kd × V²
GCp (positive, this zone/area)
GCp (negative, this zone/area)
GCpi (enclosure)
p(+) strength = qz × (GCp+ + |GCpi|)
p(−) strength = qz × (GCp− − |GCpi|)
ASD factor applied