On-Site Wastewater Treatment and Disposal Systems - Forced ...

The rock is placed in the excavation to the elevation of the pipe in-
vert. The rock must be leveled by hand to establish the proper grade.
Once the pipe is laid, more rock is carefully placed over the top of the
pipe. Care must also be taken when flexible corrugated plastic pipe is
used, because the pipe tends to "float" up as rock is placed over the
top of the pipe. One method is to employ special holders which can be
removed once all the rock is in place (see Figure 7-34).
Metal Holder
FIGURE 7-34
USE OF METAL HOLDERS FOR THE
LAYING OF FLEXIBLE PLASTIC PIPE
b. Pressure Network Pipe Placement
Pressure distribution networks are usually fabricated at the construc-
tion site. This may include drilling holes in distribution laterals.
The holes must be drilled on a straight line along the length of the
pipe. This can be accomplished best by using l-in. by l-in. angle iron
as a straight-edge to mark the pipe. The holes are then drilled at the
proper spacing. Care must be used to drill the holes perpendicular to
the pipe and not at an angle. All burrs left around the holes inside
the pipe should be removed. This can be done by sliding a smaller
diameter pipe or rod down the pipe to knock the burrs off.
Solvent weld joints are used to assemble the network. The laterals are
attached to the manifold such that the perforations lie at the bottom of
the pipe.
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