I.P.S. Pressure/Irrigation (P.I.P) Installation Guide - JM Eagle

NOTICE: Since PVC pipe is a flexible pipe, trench width and shape have little
to no effect on loading experienced by the pipe, since the maximum load
that may be carried by the pipe is that due to the column of soil directly above
the pipe outside diameter. The reason for the trench width recommendations
above are to help installers realize the economies that may result from installation
of PVC pipe over other materials, while maintaining adequate control
over backfilling, compaction and placement to limit long-term deflection.
2.4 Trench Depths
Depth is governed by surface loads, earth loads and frost penetration.
A minimum of 12 inches depth of cover is recommended where frost
penetration need not be considered. Where frost is a factor, pipe should be
buried 6 inches below the greatest recorded frost penetration. If the line will
be drained and not used in winter, frost need not be considered.
Should unusual soil conditions and/or surface loads be anticipated and the
engineer wants to calculate deflection when working with pressure pipes,
“pipe stiffness” (f/ y) can be found in Table 3.
Table 3
PIPE SDR
STIFFNESS
(psi)
PIPE SDR
STIFFNESS
(psi)
64 7 25 129
51 14 21 224
41 28 18 364
35 46 17 437
32.5 57 14 815
26 115
For more information on deflection, see Section 5.1.
IRRIGATION & I.P.S. PRESSURE INSTALLATION GUIDE
17