User Manual

DRAFT
Chapter 2 - Installation Considerations 9
Calculating Wind Load
7. Tighten the through-bolt and the lag bolt until the bracket is firmly attached to the pole and
the end of the support arm is parallel to the ground.
Figure 3: Attaching a Davit to the Wood Pole
Calculating Wind Load
Wind load is the combination of maximum weight and Effective Projected Area (EPA) that the
davit or pole can withstand. EPA, the actual projected area of an object multiplied by its
coefficient of drag, is expressed as a decimal, such as 1.3. The manufacturer of the davit or pole
should provide wind load rating specifications.
Before mounting a CCU4 collector onto the davit of a pole, you must calculate the wind load and
determine whether the combined weight and the combined EPA of the collector and any light
fixture or other equipment already installed on the davit exceeds the limits for which the
particular davit and pole are rated.
Follow the equations below to calculate wind load for each installation:
(weight of light fixture, etc.) + (weight of CCU4 and mounting hardware) = total weight
(EPA of light fixture, etc.) + (EPA of CCU4 and mounting hardware) = total EPA
The following example describes calculating the wind load for a light pole with one light fixture
and one CCU4 collector.
Wood Pole
Upsweep Arm
Lag Bolt
Through-Bolt
Downsweep Arm
Davit