When constructing or erecting objects that will be exposed to wind, it is important to know the potential loads that can be placed on the object from these winds. The load is directly proportional to the area of the object, and thus substantial loads can occur from relatively light wind gusts if the exposed area is large. Rather than take a chance on a wind gust causing a dangerous situation, you can calculate the area wind load before undertaking a project by using a mathematical formula.

- Skill level:
- Moderate

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### Things you need

- Area of object
- Drag coefficient of object (see resources section)
- Wind speed measured in miles per hour

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## Instructions

- 1
Use the following formula to calculate the area wind load of an object:

L = A x .00256 x V x V x Cd

where A is the area of the object, V is the wind speed in Mph, and Cd is the drag coefficient of the object.

- 2
Find the Cd of the object for which you are measuring area wind load. The resources section lists a web site with a table of drag coefficients for common shapes. For example, the Cd of a long cylinder like a pole is 1.2 (a hollow semicylinder opposite stream).

- 3
Multiply the area of the object by .00256. Take the resulting product and multiply it by the square of the measured (or maximum expected) wind velocity. Take this resulting product and multiply it by the drag coefficient you found in Step 2. The resulting value is the area wind load of the object.

#### Tips and warnings

- Provide for a 30 per cent increase over an expected maximum wind speed to account for unexpected gusts.
- For safety's sake and to make sure you are in compliance with any local building codes, any plans for structures or erected objects should be properly inspected and improved before proceeding.