As we are in the midst of summer storm season, many hazards are encountered during storm restoration. One hazard that randomly reveals itself is a fall due to a wooden pole breaking under the lineman’s weight. Of course, “good” wooden poles don’t break; the area of concern is the wooden pole that has reached the end of its life cycle due to decay. But how do you know if a pole is safe to climb?
To answer the question you have to consider two important facts, first you have to acknowledge that like many things, poles “wear out”. Most utility poles are made of wood treated with some type of preservative designed to extend the condition of the wood and to ward off insects and fungus. Many different types of trees are used to make utility poles, including Douglas fir, Jack Pine, Lodgepole Pine, and Pacific Silver Fir. Western Red Cedar is also popular for its natural insecticidal properties and durability, though its higher price deters many utility companies. Despite the preservatives wood poles decay and have a life of approximately 30-40 years. The second consideration is that the number of utility poles estimated in the
Before climbing a wood pole, first inspect the pole for tags. It is industry practice to supplement preservative treatment, as a result, poles are inspected periodically and if found not to have decay will be marked with a tag typically indicating year of inspection and the company who performed the inspection. Decayed poles found through the inspection to be adequately strong are treated to halt further decay. Poles found to have extensive decay are typically tagged with a red tag or some other indicator that describes the poor condition of the pole. Additional visual inspection performed prior to climbing a pole includes looking for defects, rotted or hollow spots, and defective equipment.
Rocking – Poles that have no supporting overhead equipment, or wires running straight through, can be tested by rocking by hand, with a pike, or a handline. Lack of rigidity at the ground line can indicate a break, insufficient ground support, or a major decay area.
Sounding – Involves striking the pole with a hammer around the ground line and for six feet above for evidence of hollowness and heart rot. Generally, a good pole gives solid thud as it is struck, while a hollow heart or decay pocket in the pole gives a hollow sound.
Prodding - Probing the rotted shell or decay area with a large screwdriver or other blunt tool. Prodding should be deep enough to reach solid wood but not enter it. Never use a digging bar to prod, as it may damage a good pole. Additionally, it’s not recommended to probe at the ground line unless there is cause to doubt the condition of the pole.� Openings made by prodding can become entry points for fungus which causes decay. If possible, excavate around the base of the pole to examine the condition at and below the groundline.
By using the visual and physical examination techniques describe in this tailgate, you can have confidence in your ability to safely assess the condition of a pole to determine structural integrity.