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.