Wind Velocity Chart
| Class/Design Pressure in PSF (inches of water) | Class/Design Pressure Equivalent Wind Velocity in MPH | Structural Test Pressure in PSF (inches of water) | Structural Test Pressure Equivalent Wind Velocity in MPH | Water Test Pressure in PSF (inches of water) | Water Test Pressure Equivalent Wind Velocity in MPH |
|---|---|---|---|---|---|
| 15 (2.88) | 77.52 | 22.50 (4.32) | 94.94 | 2.86 (0.55) | 33.85 |
| 20 (3.84) | 89.51 | 30.00 (5.76) | 109.63 | 3.00 (0.58) | 24.67 |
| 25 (4.80) | 100.08 | 37.50 (7.20) | 122.57 | 3.75 (0.72) | 38.76 |
| 30 (5.76) | 109.63 | 45.00 (8.64) | 134.27 | 4.50 (0.86) | 42.46 |
| 35 (6.72) | 118.42 | 52.50 (10.08) | 145.03 | 5.25 (1.01) | 45.86 |
| 40 (7.68) | 126.59 | 60.00 (11.52) | 155.04 | 6.00 (1.15) | 49.03 |
| 45 (8.64) | 134.27 | 67.50 (12.96) | 164.45 | 6.75 (1.30) | 52.00 |
| 50 (9.60) | 141.53 | 75.00 (14.40) | 173.34 | 7.50 (1.44) | 54.82 |
| 55 (10.56) | 148.44 | 82.50 (15.84) | 181.80 | 8.25 (1.58) | 57.49 |
| 60 (11.52) | 155.04 | 90.00 (17.28) | 189.89 | 9.00 (1.73) | 60.05 |
| 65 (12.48) | 161.37 | 97.50 (18.72) | 197.64 | 9.75 (1.87) | 62.50 |
| 70 (13.44) | 167.47 | 105.00 (20.16) | 205.10 | 10.50 (2.02) | 64.86 |
| 75 (14.40) | 173.34 | 112.50 (21.60) | 212.30 | 11.25 (2.16) | 67.14 |
| 80 (15.36) | 179.03 | 120.00 (23.04) | 219.26 | 12.00 (2.30) | 69.34 |
| 85 (16.32) | 184.54 | 127.50 (24.48) | 226.01 | 12.00 (2.30) | 69.34 |
| 90 (17.28) | 189.89 | 135.00 (25.92) | 232.56 | 12.00 (2.30) | 69.34 |
| 95 (18.24) | 195.09 | 142.50 (27.36) | 238.94 | 12.00 (2.30) | 69.34 |
| 100 (19.20) | 200.16 | 150.00 (28.80) | 245.14 | 12.00 (2.30) | 69.34 |
| Air Infiltration Pressure in PSF (inches of water) | Equivalent Wind Velocity in MPH |
|---|---|
| 1.57 (0.30) | 25.08 |
| 6.24 (1.20) | 50.00 |
These values are calculated from the Ensewiler Formula, P = .002496 V2, where V = Wind Velocity in MPH and P = the Differential Pressure across the window in Pounds per Square Foot (PSF).The equation assumes the direction of wind is perpendicular to the window and there are no effects from surrounding terrain or the shape of the building in which it is installed. Positive (+) pressures act inward and Negative (-) pressures act outward on the window.
An easier way to perform this calculation would be as follows:
Square Root of PSF X 20.016 (e.g. 15 Sq.Rt. = 3.87 X 20.016 = 77.52)
