Trenching

Care must be taken not to drag PVC pipe on the ground and cause wear on the pipe or to the spigot. Any excessively rough handling of the pipe can lead to leaks and breaks when the system is activated and pressurized.

Trenching and Excavating
Refer to OSHA standards regarding current safety regulations pertaining to excavation. The trench shall be sloped, supported, or drained when necessary so that the workers can work safely. The trench depth should be at least 6" below the deepest frost penetration.

Trench Width
The trench width at the ground surface may vary with and depend upon the depth and the type of soils. The minimum clear width of the trench measured at the springline of the pipe should be at least one foot greater than the outside diameter of the pipe to enable backfill material to be installed in the haunching area. If this trench width is exceeded, pipe zone haunching should be compacted to a point of at least 3 pipe diameters from the pipe on both sides of the pipe or to the trench walls, whichever is less.

Preparation of Trench Bottom
Regardless of the type of excavating equipment used, the trench bottom should be smooth and free from rocks, dirt clods, and frozen material. If the trench bottom is hard, a 4" layer of soft granular material should be spread evenly along the bottom of the trench.