What does this ASCE 7-22 C&C calculator compute?

It computes velocity pressure at height and mean roof height and returns net design pressures p = qz·GCp − qi·GCpi for both internal pressure signs, in psf or kPa.

Does the tool include code-lookup tables for Kz or GCp?

No. To respect licensing, the tool requires you to input Kz and GCp from the official standard or your firm’s library. It then performs accurate calculations and envelopes.

Is Kd included for Components & Cladding in this tool?

Kd is a user-editable input. Default is 0.85. Consult ASCE 7-22 and your jurisdictional practice for whether to include it in C&C.

Can I switch between Imperial and SI units?

Yes. Choose Imperial (mph, ft, psf) or Metric (m/s, m, kPa). The tool converts constants accordingly.

Will the calculator save or share my inputs?

Use the Share link to copy a URL with query parameters that preserve your inputs, useful for peer review.

Is this a substitute for sealed engineering calculations?

No. The tool assists professionals but does not replace engineering judgment, peer review, or sealed documents.

ASCE 7-22 Wind Load Calculator (Components & Cladding)

Data Source and Methodology

Authoritative Data Source: ASCE/SEI 7-22, Minimum Design Loads and Associated Criteria for Buildings and Other Structures (Chapter 26 and Chapter 30 for Components & Cladding), 2022. Official information is available from the American Society of Civil Engineers: ASCE 7 Standard. Selected overview and educational resources: STRUCTURE Magazine summary, ASCE Amplify (Chapter 30), Engineering Express: Wind Loads per ASCE 7.

All calculations strictly follow the formulas and coefficient relationships provided by this source. To respect licensing, this tool does not reproduce proprietary tables (e.g., Kz or GCp). Instead, it performs accurate computations using your verified inputs from ASCE 7-22 or your firm’s library.

The Formula Explained

$$\text{Imperial: } q = 0.00256 \cdot K_z \cdot K_{zt} \cdot K_d \cdot V^2 \cdot I \quad [\text{psf}]$$ $$\text{SI: } q = 0.613 \cdot K_z \cdot K_{zt} \cdot K_d \cdot V^2 \cdot I \quad [\text{kPa}]$$ $$p = q_z \cdot (GC_p) - q_i \cdot (GC_{pi})$$ Where: $$q_z = \text{velocity pressure at component height}, \quad q_i = \text{velocity pressure at mean roof height}$$ The tool evaluates net pressures for both internal pressure signs, using $GC_{pi} = \pm |GC_{pi}|$, and reports the envelope.

Glossary of Variables

V: Basic wind speed (3-sec gust; mph or m/s).
Kz: Exposure coefficient at the point of interest (component height).
Kz,MRH: Exposure coefficient at mean roof height (for internal pressure, labeled Kz at MRH in the tool).
Kzt: Topographic factor (≥ 1.0 where speed-up applies).
Kd: Directionality factor (commonly 0.85; confirm per practice).
I (Iw): Importance factor for wind (often 1.0; verify per ASCE 7-22).
GCp: External pressure coefficient for the C&C zone and effective wind area (may be positive or negative).
|GCpi|: Magnitude of internal pressure coefficient; tool evaluates both ± signs.
qz, qi: Velocity pressures at component height and at mean roof height.
p: Net design pressure on the component or cladding surface.

Worked Example: Step-by-Step

How It Works: A Step-by-Step Example

Assume Imperial units. Enter V = 140 mph, Kz = 0.98 (component height), Kz,MRH = 1.03, Kzt = 1.0, Kd = 0.85, I = 1.0, GCp = −0.90, and |GCpi| = 0.18.
Compute velocity pressures: qz = 0.00256 × 0.98 × 1.0 × 0.85 × 140² × 1.0 = 42.2 psf (approx), qi = 0.00256 × 1.03 × 1.0 × 0.85 × 140² × 1.0 = 44.4 psf (approx).
Evaluate both internal pressure signs:
- p(+|GCpi|) = qz·GCp − qi·(+0.18) ≈ 42.2×(−0.90) − 44.4×0.18 = −38.0 − 8.0 = −46.0 psf
- p(−|GCpi|) = qz·GCp − qi·(−0.18) ≈ 42.2×(−0.90) + 44.4×0.18 = −38.0 + 8.0 = −30.0 psf
Envelope: Maximum pressure ≈ −30.0 psf (less suction), Maximum suction ≈ −46.0 psf (more negative).

Note: Use code-authorized values for Kz and GCp from ASCE 7-22 tables for your exact exposure, height, zone, and effective wind area.

Frequently Asked Questions (FAQ)

Does this calculator replace code tables?

No. To honor ASCE licensing and ensure accuracy, you enter coefficients from the official standard; the tool performs precise computations and envelopes the results.

What’s the difference between qz and qi?

qz is evaluated at the component height; qi is evaluated at mean roof height and used with the internal pressure coefficient GCpi.

How do I choose GCp?

GCp depends on the C&C zone, geometry, and effective wind area. Use the correct sign and magnitude from ASCE 7-22 Chapter 30 for your case.

Can I include or exclude Kd?

Kd is user-editable (default 0.85). Practices vary for C&C; confirm with ASCE 7-22 and your AHJ. The tool transparently applies whatever you specify.

Is the result LRFD or ASD?

The p values here are nominal pressures based on input coefficients. Apply load factors or combinations per your design methodology outside the tool.

Will this work on small screens?

Yes. The interface is mobile-first and fully keyboard-accessible with visible focus states and high contrast.

What are typical |GCpi| values?

They depend on enclosure classification. Consult ASCE 7-22 for authoritative values; 0.18 and 0.55 are commonly encountered magnitudes in practice.

Tool developed by Ugo Candido. Contents verified by CalcDomain Engineering Editorial Board.
Last reviewed for accuracy on: September 14, 2025.