This illustration shows the best practice for venting and drainage hole placement and dimensions for pipe columns and girders as well as street light and transmission poles with base-plates and with or without cap-plates.

Location of Openings

1. The most desirable fabrication is to have the end completely open, with the same diameter as the section top and bottom.
2. This is an equal substitute if the full opening is not allowed.
3. This is an equal substitute if the full opening is not allowed.
4. This is an equal substitute if the full opening is not allowed.
5. This must be used when no holes are allowed in the cap or base-plate: two half-circles 180 degrees apart and at opposite ends of the pole.

Dimensions

Openings at each end must be at least 30% of the cross-sectional area of the pipe, for pipe 3” (8 cm) and greater and 45% of the cross-sectional area for pipe smaller than 3” (8 cm).

1. End completely open
2. Slot A = 3/4" (19 mm), Center Hole B = 3 inches (7.6 cm) in diameter
3. Half Circle C = 1 3/4" (4.5 cm) radius (examples of sizes for 6" (15 cm) diameter section)
4. Oval Opening = 1 3/4" (4.5 cm) radius
5. Half Circle D = 5/8" (1.9 cm) radius