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