Wind Load vs. Wind Speed
When moving air - wind - is stopped by a surface - the dynamic energy in the wind is transformed to pressure. The pressure acting the surface transforms to a force
Fw = pd A
= 1/2 ρ v2 A (1)
where
Fw = wind force (N)
A = surface area (m2)
pd = dynamic pressure (Pa)
ρ = density of air (kg/m3)
v = wind speed (m/s)
Note - in practice wind force acting on a object creates more complex forces due to drag and other effects.
Wind Load Calculator
| Wind Speed (m/s) | Wind Load1) (Pa) |
|---|---|
| 1 | 0.6 |
| 2 | 2.4 |
| 3 | 5.4 |
| 4 | 9.6 |
| 5 | 15 |
| 6 | 22 |
| 7 | 29 |
| 8 | 38 |
| 9 | 49 |
| 10 | 60 |
| 11 | 73 |
| 12 | 86 |
| 13 | 101 |
| 14 | 118 |
| 15 | 135 |
| 16 | 154 |
| 17 | 173 |
| 18 | 194 |
| 19 | 217 |
| 20 | 240 |
| 21 | 265 |
| 22 | 290 |
| 23 | 317 |
| 24 | 346 |
| 25 | 375 |
| 26 | 406 |
| 27 | 437 |
| 28 | 470 |
| 29 | 505 |
| 30 | 540 |
| 31 | 577 |
| 32 | 614 |
| 33 | 653 |
| 34 | 694 |
| 35 | 735 |
| 36 | 778 |
| 37 | 821 |
| 38 | 866 |
| 39 | 913 |
| 40 | 960 |
| 41 | 1009 |
| 42 | 1058 |
| 43 | 1109 |
| 44 | 1162 |
| 45 | 1215 |
| 46 | 1270 |
| 47 | 1325 |
| 48 | 1382 |
| 49 | 1441 |
| 50 | 1500 |
1) density of air 1.2 kg/m3
- 1 m/s = 3.6 km/h = 196.85 ft/min = 2.237 mph
- 1 Pa = 1 N/m2 = 1.4504x10-4 psi (lb/in2)
Example - Hurricane Wind Load acting on a Wall Surface
A hurricane with wind speed 35 m/s is acting on a 10 m2 wall. The dynamic force can be calculated as
Fw = 1/2 ρ v2 A
= 1/2 (1.2 kg/m3) (35 m/s)2 (10 m2)
= 7350 N
= 7.35 kN
Or - from the table above the wind load per square metre is 735 N/m2. The total load on the wall can be calculated as
(735 N/m2) (10 m2) = 7350 N
A hurricane acting on a 10 m2 wall creates a force equal to the weight of aprox. 750 kg.
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