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

is produced by Wavin and Glynwed Pipe Systems in diameters from 4 to 12 inches (100 to 300 mm) and
is made from PE3408 resin. The liner is only intended to be a semi-structural liner (Class II). At the
present time, Subcoil is not distributed in the US.
Mainsaver
Originally called Cemfil, Mainsaver was first introduced in the UK in 1999 and later in the US in 2006.
Marketed by Mainsaver out of Golden, CO, approximately 5,000 feet (1,524 meters) of the product has
been installed in several municipal water systems in the Rocky Mountain region. Annual installations of
Mainsaver are expected to grow to 20,000 feet (6,098 meters) per year. Mainsaver is a flexible MDPE
tube with integral grout key hooks on the outside surface. Before insertion of the tube, any open service
connections are robotically plugged so that grout cannot migrate. After the tube is inserted into the main,
a proprietary grout is placed between the tube and the host pipe, and a rounding swab is driven through
the tube by air pressure. The swab progressively expands the tube and distributes the grout against the
interior surface of the host pipe. Air pressure is maintained for 16 hours to allow time for the grout to
hydrate. After hydration, the liner is inspected with closed circuit television (CCTV) and infrared
thermography (as a QC check against grout voids). Mainsaver’s RoboTap is used to remotely reinstate
any plugged service connections and special end seals are installed to protect the ends of the new liner.
The liner can be laid through 22.5 o long radius elbows and renewal lengths of up to 500 feet (152 meters)
are possible. The cementitious grout provides corrosion protection to the underlying ferrous mains, while
the PE liner ensures water quality. Mainsaver is not a fully structural liner, but rather a semi-structural
liner that relies upon adhesion to the host pipe for strength (Class III). It can be used with ferrous or
cementitious pipes. Mainsaver is available in diameters 4 to 12 inches (100 to 300 mm). The total
thickness of the PE and grout is approximately 3/16 inches (3 mm). It can bridge a maximum hole size of
2.4 or a gap of 0.4 inches (10 mm) with pressures up to 294 psi (30 bar). The cost for installing
Mainsaver was said to be comparable to cement mortar lining, but no cost data were provided.
On-Site Folded PE Close-Fit Lining
The close-fit PE liners that are available in larger diameters tend to be on-site folded products. The
relationship between the diameter of pipe and the maximum thickness (lowest SDR) that can be folded is
given in Figure 3-14. Note that the higher strength PE4710 (PE100) is less capable of being folded than
the standard grade.
1600
1400
1200
1000
Maximum
Diameter - mm 800
600
400
200
0
26 33 42 50 61 80
Liner SDR
Figure 3-14. Relationship Between Diameter and SDR for Folding
27
PE80
PE100