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ASCE 7-22 Wind Velocity Pressure qz

Eq. 26.10-1, qz = 0.00256·Kz·Kzt·Ke·V². In ASCE 7-22 the directionality factor Kd is no longer in qz — it moved into the pressure equations. Many “ASCE 7-22” tools still put Kd here; applying it again in the pressure equation under-predicts pressure by 15%. Kz uses the ASCE 7-22 formula (coefficient 2.41) and the revised terrain constants.

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Kz Table 26.10-1—
Ke §26.9—
qz Eq. 26.10-1—

Kd (Table 26.6-1; 0.85 for buildings) is applied in the pressure equations, e.g. p = q·Kd·G·Cp − qi·Kd·(GCpi) (Eq. 27.3-1). Do not apply it to this qz and again later.

Table 26.10-1 Note 1Kz = 2.41(15/zg)2/α for z < 15 ft; 2.41(z/zg)2/α for 15 ft ≤ z ≤ zg; 2.41 above zg (ASCE 7-16 used 2.01). The formula is permitted; tabulated values may differ by ±0.01 from rounding.
Table 26.11-1Constants used — B: α = 7.5, zg = 3,280 ft; C: α = 9.8, zg = 2,460 ft (check: Kz(33 ft, C) = 1.00 by definition → zg ≈ 2,456 ft); D: α = 11.5, zg = 1,935 ft (single secondary source; within 1% of tabulated Kz). The zmin column of Table 26.11-1 is for the gust-effect factor, not a floor for Kz.
VerifyExposure B, ASCE 7-22-specific values at 50 / 100 / 200 ft: 0.79 / 0.95 / 1.14 (ASCE 7-16: 0.81 / 0.99 / 1.20). Published example: Exposure C, z = 15 ft, V = 100 mph, Kz = 0.85 → qz = 21.76 psf.
ScopeVelocity pressure only. Pressures and forces (Chapters 27–30), gust-effect factor, enclosure classification and tornado loads (new Chapter 32) are separate steps.

Preliminary calculation tool. Final design requires the full text of the referenced standard (see the sources on this page) and review by a licensed PE.