Page 479 - Trenchless Technology Piping Installation and Inspection

Glossary of Terms 429

Pipe splitting: Replacement method for breaking an existing pipe by
longitudinal slitting. At the same time a new pipe of the same or larger
diameter may be drawn in behind the splitting tool. See also pipe bursting.

Pipeline rehabilitation: See pipeline renewal.
Pipeline renewal: The in-situ renewal of an existing pipeline, which has
become deteriorated. The selection of appropriate renewal method is
dependent on type of application and characteristics and types of defects
of the existing pipe. See Chap. 2 for method selection criteria.
Plastic: Any of a variety of thermoplastic and thermoset material used
in pipeline construction and renewal (e.g., polypropylene, PVC, fiberglass
reinforced plastics, polyester felt reinforced pipe, epoxy and polyester
mortars, and so on).
Point CIPP: CIPP techniques entail impregnating fabric with a suitable
resin, pulling this into place within the sewer around an inflatable packer
or mandrel, and then filling the packer with water, steam, or air under
pressure to press the patch against the existing sewer wall while the resin
cures.
Point repairs: Repair works on an existing pipe, to an extent less than the
run between two access points or manholes.

Point source repair: See localized repair.
Polyester: Resin formed by condensation of polybasic and monobasic
acids with polyhydric alcohols.
Polyethylene: A ductile, durable, virtually inert thermoplastic composed
by polymers of ethylene. It is normally a translucent, tough solid. In pipe
grade resins, ethylene-hexene copolymers are usually specified with
carbon black pigment for weatherability.

Polymer coating: It is a thermoset coating made up of inert plastic-like
epoxies, urethanes and ureas, polyesters, which have a high resistance to
corrosion; they are applied by trained professionals using special spraying
equipments and as per the manufacturers specifications.
Polyolefin: A family of plastic material used to make pipes.
Polypropylene (PP): A type of plastic pipe from the polyolefin family.
Potholing: Digging a vertical hole to visually locate a utility.
Preparatory cleaning: Internal cleaning of pipelines, particularly sewers,
prior to inspection, usually with water jetting and removal of material
where appropriate.
Preventative maintenance: Routine maintenance designed to prevent
pipeline system failures and resulting emergency repairs.
Product pipe: Permanent pipeline for operational use. Pipe for conveyance
for water, gas, sewage, and other products.