Proper Venting and Drainage Hole Placement and Dimensions for Rectangular Tube Truss
Each vertical member should have two holes at each end, 180 degrees apart, in line with the horizontal members. Hole locations for the vertical members should be as shown in A and B.- The size of the holes preferably should be equal, and the combined area of the two holes at either end of the verticals should be at least 30% of the cross-sectional area.
End-plates – Horizontal
- The most desirable fabrication is completely open.
- If H + W = 24” (61 cm) or larger, the area of the hole, plus clips, should equal 25% of the area of the tube (Area = H x W).
- If H + W is between 16” and 24” (41-61 cm), the area of the hole, plus clips, should equal 30% of the area of the tube.
- If H + W is between 8” and 16” (20-41cm), the area of the hole, plus clips, should equal 40% of the area of the tube.
- If H + W is less than 8” (20 cm), the tube should be left open.
