The following four factors are crucial to understanding how to choose a pole correctly: EPA (Effective Projected Area), Force Speed, Wind Speed, and the effective Friction Coefficient on the fixture.
Effective Projected Area
EPA, calculated in square feet, is the maximum surface area of the pole exposed to wind force. EPA multiplied by wind speed is equal to the force applied to the pole.
Wind speed is a sudden increase in wind speed that can cause an instantaneous pole movement. All Depar Energy poles are designed to withstand beyond constant wind speeds with a force factor of 1.3. Engineering data for the posts are available on the cut sheets.
Constant Wind Speed
This is the maximum constant speed expressed in miles per hour that is expected to occur at a given location.
The friction coefficient is a factor number applied to reflect different levels of drag in different ways. For example, a square fixture will have more friction and therefore a higher coefficient of friction than a round fixture. When calculating the EPA of a fixture, we take the Actual Projected Area and multiply it by the drag coefficient (EPA = APA x Coefficient of Friction).
Pole Selection Steps
Identify all the lighting equipment used (fixtures, elbows, arms, etc.).
Add up the EPAs of each component used to get the total.
Use the wind chart provided to find the maximum constant wind speed for the site location of your pole (s).
With the above information, contact Depar Energy for a precise price quote.
The maximum EPA supported by each pole is shown on the direct cut sheets. The provided wind chart provides an overview of the maximum constant speed. Please refer to local sources and regional climate data as there are some places with unusual wind conditions. The pole selection procedures discussed here are a simple guide. A qualified professional should be consulted to verify the overall system design (post, fixture, elbow, arm, base, foundation, and accessories).