Wind Force and Swing on a Suspended Load
Velocity pressure, lateral wind force, and swing angle on a suspended load from the sail area, wind speed.
Example
You enter
- Projected sail area (ft²) 200
- Sustained wind at the load (mph) 20
- Shape coefficient (flat panel ~1.2-2.0) 1.6
- Load weight (lb) 4000
You get
- Velocity pressure 1.024 psf
- Lateral wind force 327.7 lb
- Swing angle off vertical 4.7 deg
Checked against published worked examples from: ASCE 7 velocity pressure / OSHA 1926 Subpart CC.
Details, formula, and sources
ScopeVelocity pressure, lateral wind force, and swing angle on a suspended load from the sail area, wind speed, and shape coefficient. The manufacturer's in-service wind limit governs.
Formula or tableq = 0.00256 x V^2 (ASCE velocity-pressure constant); wind_lb = q x sail_area x shape_coef; swing_deg = atan(wind_lb / load_weight) x 180 / pi.
Source and editionASCE 7 velocity-pressure constant (the same 0.00256 the wind-pressure tile uses) and OSHA 1926 Subpart CC by name; first-principles.
Free accessThe 0.00256 velocity-pressure constant is public (ASCE 7). OSHA 1926 Subpart CC is free at osha.gov.
What governsEstimate. Head rigger and manufacturer working-load-limit charts govern. Inspect every piece of hardware before the show.
API field namessail_area_ft2, wind_mph, shape_coef, load_weight_lb, q_psf, wind_lb, swing_deg
- Velocity pressure q = 0.00256 V^2 (V in mph, q in psf)ASCE 7
- Shape coefficient flat panel ~1.2-2.0 (default 1.6)ASCE 7 force coefficients