WIND RATING
Wind Rating: The primary function of a light pole is to resist the physical forces of luminaire weight, ice and wind loads that poles may encounter over their expected design life. Along with the foundation system, the primary force a pole must withstand is from the wind. A Wind Rating map is used for pole selection (see below). Because of the variety of pole shapes, heights, size and quantity of luminaires to be supported (including other items that may be attached to the pole), an engineering analysis must be done to ensure the customer will receive a pole adequate for the task. It must be capable of providing a long service life, be relatively maintenance free, and be aesthetically pleasing. Due to unforeseen loadings and wind events which may occur, it is advisable to select a pole with an ample margin of structural capacity.
EPA
 
This is not the Environmental Protection Agency.
 
Light fixtures or luminaires are rated in EPA ( E ffective P rojected A rea) which refers to the apparent wind profile of a fixture or object based on its’ geometric shape. It helps to think of a sail on a boat that “catches” the wind – because some fixture shapes and sizes can “catch” the wind, just like a sail, more than others.
For example, a round fixture being more streamlined has a lower EPA than a flat sided fixture of the same profile, since the wind passes around the round shape easier.
 
Engineers can measure how much a fixture will “catch” the wind, and EPA is the technical term used. If you think of slipping through the wind easily with little resistance (Low EPA) vs catching and grabbing a lot of the wind (Higher EPA) – - you’ve got the idea. 
Mountains, coastal areas and shorelines around the Great Lakes will experience different levels of wind speeds than other inland areas.
 
Consulting a local Engineering firm is the best way to ensure you are purchasing equipment that can stand up to windy areas.
The best way to determine the requirements of the project is to:

1.Determine the geographic location of the light pole and fixture
 
2.Determine to total weight and EPA of the pole and fixture (Check the Spec Sheets for EPA values)
 
3.Determine the wind load requirement (see map below)
 
4. Check with the pole manufacturer to ensure the pole can support the weight of the fixture and hold up to the wind load
 
If additional engineering calculations are required you should contact a local Engineering firm. These typically are not extremely expensive and some range from $500 - $1000 for signed and sealed calculations.

Bill Nagengast, Lighting Engineer
Solas Ray Lighting
Holds over 20 patents in the lighting industry.
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TJ-42 9.14.18