State of Technology Report for Force Main Rehabilitation, Final ...

pipe size that minimizes the interstitial gap and therefore loss of capacity. The thickness of HDPE can
also be a negative factor for flow, especially for high pressure. An SDR 11 is needed for a 160 psi
(11 bar) pressure rating and SDR 17 for a 100 psi (7 bar) pressure rating. Of course, this is based on
using the pipe as a fully structural pipe since a slipliner is independent, not interactive, with the existing
host pipe.
FusiblePVC
In 2003, Underground Solutions introduced a patented
PVC pipe product that could be butt fused together,
much in the same manner as HDPE (Figure 3-22).
Their first commercial installation was in January 2004
and since over 2 million linear feet (0.6 million meters)
have been installed. FusiblePVC has been used in over
43 states, plus Canada and Mexico. The primary use
has been for pressurized potable water, reclaim, and
wastewater lines.
The resin and compound meets the PVC formulation in Figure 3-22. Fusion of PVC Joint
PPI Technical Report #2, so the same hydrostatic design stress may be used (2009). The fusible pipe
meets both AWWA C900 and AWWA C905, is made in DI pipe size (DIPS) and iron pipe size (IPS) OD
series, and is NSF 61 certified for use with potable water. With the proprietary formulation, the fused
joint is nearly as strong (minimum 95%) as the pipe wall.
With the fully restrained butt-fused joints, FusiblePVC can be used for directional drilling, pipe bursting,
and sliplining. The same equipment that is used for butt welding PE pipe can be used for PVC.
However, the fusion temperature, time, and pressure are different and only technicians that have been
trained and certified by Underground Solutions are permitted to fuse joints. Certification lasts one year.
Fusible C-900 ® , designed for water distribution systems, is available in diameters of 4 to 12 inches (100
to 300 mm) with DRs of 14, 18, and 25. Fusible C-905 ® , designed for water transmission systems, is
available in diameters of 14 to 36 inches (350 to 900 mm) with DRs of 14, 18, 21, 25, 32.5, 41, and 51.
AWWA C-900 and C905 incorporates a long-term factor of safety of 2 with no surge allowance.
Transient pressure is added to working pressure for maximum pressure and is not to exceed 1.6 times the
pressure class of the pipe. Underground Solutions also produces FPVC, which is Fusible PVC in
diameter dimensions other than the DIPS and IPS series in the AWWA standards.
For sliplining, the host pipe would be moderately cleaned and a CCTV inspection made. The degree of
cleaning is not as stringent as for close-fit liners. Depending on site logistics, the Fusible PVC can be
strung out and the joints butt fused above grade prior to insertion or butt fused in the ditch. The fused
PVC is then winched into the host pipe, following the maximum recommended pull force which is based
on either an axial stress of 2,600 psi (179 bar) or a factor of safety of 2.25 against joint strength,
whichever is less. Sliplining lengths of 3,500 feet (1,067 meters) in a single pull have been completed.
Discrete Pipe Lengths
Some of the same diameter and thickness considerations apply when sliplining with discrete pipe lengths.
Normally, discrete pipe lengths will have bell and spigot joints or coupling joints with an outside diameter
greater than the barrel of the pipe. Often, it is the outside dimension of this joint that will control the
nominal diameter for insertion. Some pipe manufacturers make a special low profile joint to facilitate the
insertion. The process for the insertion of discrete pipe lengths is to set up and assemble each pipe joint
one at a time in the ditch. Next, the column of pipe is jacked forward by the length of each pipe section,
before making the next joint assembly. Discrete pipe sliplining is favored when job site logistics are not
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