Page 196 - Trenchless Technology Piping Installation and Inspection

160 Cha pte r F o u r

enabling the design of a complete PVC system. It also allows
municipal entities to inventory a single type of fittings and
restraints for all situations. Tapping is also performed in the
same manner as gasket-joint PVC pipes.
2. TerraBrute™: This product meets AWWA C900 standard
requirements, but has a modified bell-and-spigot joint as
shown in Table 4.10. Currently manufactured in diameters of
up to 12 in., this pipe has been used in several buried and at
least one nonburied pressure application in Canada. The bell-
and-spigot joint modification increases the tensile load capac-
ity of the pipe joint by a factor dependant on the diameter
and the wall thickness of the pipe. Also, controlling the num-
ber of pins, pin diameter, depth of groove in the spigot, and
wall thickness of the internal ring can optimize the tensile
capacity of the joint. Installation involves insertion of the
spigot into the bell, alignment of the pins with the metal band
built into a groove on the spigot, and then hammering down
of the pins. Once again, utilities in Canada have the ability to
build complete PVC systems, even when portions of a project
comprise trenchless construction.
3. Certa-Lok C900/RJ™: This is another product conforming to
AWWA C900 and C905 standards, with a proprietary joint
type that makes the product ideal for trenchless installation
via HDD. The pipe is also NSF certified for potable water
usage. This was the only PVC alternative for trenchless con-
struction in the past decade. The Certa-Lok C900/RJ is used
in the new construction of water distribution or transmission
lines or sewer force mains, or for new gravity sewer main
installation. The joint has a groove machined in the pipe and
in the coupling to allow the insertion of a flexible thermoplas-
tic spline that provides a full 360° restrained joint with evenly
distributed loading. Available diameters currently include
4 through 16 in., in both DR18 and DR14. The recent intro-
duction of 16-in. pipe uses a fiberglass-based coupling joint
system. According to contractors, availability of 16 in. pipe
has been an issue since it was introduced.
4. Internally restrained PVC pipe: This product also conforms to
AWWA C900. The joint is patented and is licensed to several
PVC pipe and fabricated fitting manufacturers. The mecha-
nism consists of a metal casing that sits adjacent to the Rieber
gasket in the bell; and the casing is molded into the “race-
way” of the bell during pipe belling. A C-shaped grip-ring
with several rows of unidirectional serrations is manually
inserted into the casing at the manufacturing facility. Both the
casing and the grip ring are made of ductile iron that has been