Wind From the code or the brief

Design Wind Speed m/s

The gust speed the wind code or the installer's brief sets for the site, not a daily mean. km/h divided by 3.6.

Air Density kg/m³

Standard sea-level air is 1.225; thinner at altitude, denser in cold.

Force Coefficient x

The code's coefficient for a canopy or free-standing fabric of your shape, pitch and blockage. The default is a placeholder, not a recommendation.

Sail & Fixings From the drawing

Sail Area m²

The fabric area the wind acts on, not the footprint of a sloped sail.

Fixing Points points

Share of the Load on the Worst Fixing %

Corners do not share equally; the engineer sets the share the most loaded anchor carries. 100 / fixings is the equal share.

Wind Force on the Sail

— kN

Dynamic pressure times the force coefficient times the area

Loads

Dynamic Pressure: — Pa
Dynamic Pressure: — kgf/m²
Wind Force: — kgf
Equal Share per Fixing: — kN
Load on the Worst Fixing: — kN
Load on the Worst Fixing: — kgf
Design Wind Speed: — km/h
Force at 10% More Wind: — kN

The physics is the dynamic pressure of moving air, half the density times the speed squared, multiplied by a force coefficient and the area. Everything that makes a real canopy differ from a flat plate, its pitch, curvature, edge shape, the blockage behind it and the gust factor, sits in the force coefficient and the design speed, and both belong to the wind code for the site (EN 1991-1-4, ASCE 7, AS/NZS 1170.2 or the local equivalent) and to the engineer who applies it. Knitted shade cloth sheds part of the load through its open area; the maker's reduction, if any, applies to the force shown here, and a coated or solid fabric takes it all. Fabric pretension adds to the corner loads on top of the wind and is not included. **This is the wind-load arithmetic for a quotation or a sanity check; the fixings, posts and footings are the engineer's design.**

Shade Sail & Awning Wind Load: Pressure, Force & Load per Fixing — free, with the formula and a worked example, at Textile School.