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

Subline
Subline, offered by Subterra, is a close-fit and fold-and-form liner made
of standard grade PE (PE3408). After butt-fusion welding, the
continuous liner is pushed through a former that folds the liner into a
“C” shape and temporarily maintained by restraining bands (see Figure
3-15). After insertion, the liner is pressurized with water at ambient
temperature breaking the bands and reverting the pipe back to its
original dimensions. The liner can negotiate up to 45 o bends during
insertion. Proprietary couplings are then attached to the end of the
exposed pipe sections and make-up pieces are inserted to reconnect to
the existing main. Installations of up to 3,500 feet (1,067 meters) are
achievable. Subline is designed to be a thin-wall PE liner that bridges
over holes and gaps in the host pipe (semi-structural – Class II) and
comes in diameters from 3 to 60 inches (75 to 1,600 mm). Thicknesses
range from 0.12 to 0.80 inches (3 to 20 mm).
PolyFold
In 2008, Insituform Blue introduced two close-fit PE liner products, one
being a fold-and-form product called PolyFold (Figure 3-16). Like
PolyFlex, PolyFold is made with the improved toughness and crack
resistant PE4710 (PE100) resin. PolyFold is available in diameters from
4 to 63 inches (100 to 1,575 mm) and pressure ratings up to 150 psi (10.3
bar). With NSF 61 certification, PolyFold also is suitable for potable
water applications. PolyFold is site folded into a “C” by pushing the
continuous PE pipe through a folding machine and then banding the
folded shape. A diameter reduction of up to 40% can be achieved, which
greatly facilitates the insertion of PolyFold into an existing pipe.
PolyFold can easily navigate bends up to 22.5 o . Once the liner is in place,
it is cut to length, end fittings are attached, and the liner is pressurized to
snap the bands. Depending on the pressure and diameter, PolyFold can
either be a semi-structural or fully structural liner for a sewer force main.
3.4.3.3 Fold-and-Form Close-Fit Lining – PVC (Alloy)
Factory-Folded PVC Close-Fit Lining
Figure 3-15. Subline
Forming into “C” Shape
Figure 3-16. PolyFold TM
Banding
All of the fold-and-form liners based on PVC resin formulations are factory-folded as heat is required to
deform the liner.
Ultraliner PVC Alloy Pipeliner
PVC Alloy Pipeline was first introduced in 1994 by Ultraliner and since then the company has installed
over 4.5 million feet (1.37 million meters) of liner. The usage of Ultraliner appears to be equally
dispersed across its diameter range of 4 to 30 inches (100 to 750 mm). PVC Alloy Pipeliner has been
used in 36 states and is approved by 30 State Departments of Transportation (DOTs) for use on drainage
culverts, which is one of Ultraliner’s largest markets.
Ultraliner PVC Alloy Pipeline is a solid wall PVC pipe manufactured from virgin PVC homopolymer
resin with no fillers, which is later modified with special additives to improve ductility and toughness.
The Pipeliner is collapsed flat and coiled on a reel in continuous, jointless lengths. Small diameters (12
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