Page 477 - Trenchless Technology Piping Installation and Inspection

Glossary of Terms 427

Modified sliplining: A range of techniques in which the liner is reduced in
cross-sectional diameter before insertion into the carrier pipe. It is
subsequently restored close to its original diameter, generally forming a
close-fit with the original pipe. There are different methods of cross
sectional area reduction.
Needled felt: A highly absorbent felt material specially designed for the
CIPP tube fabrication.
Non-worker entry: Size of pipe, duct, or bore, less than that for worker-entry.
Occupational illness: Any abnormal condition or disorder caused by
exposure to environmental factors associated with employment. For
excavations this might include illnesses caused by the inhilation of toxic
vapors.
Open-cut: The method by which access is gained to the required level
underground for the installation, repair, or replacement of a pipe, conduit,
or cable. The excavation is then backfilled and the surface restored.
Open face shield: Shield in which manual excavation is carried out from
within a steel tube at the front of a pipe jacking operation.
On-site wet-out: A non-factory tube wet-out that is performed over the
hole in the field.

Ovality: There are two definitions: (1) the difference between the
maximum and mean diameter divided by the mean diameter, and (2) the
difference of the mean and minimum divided by the mean, at any
one cross section of a pipe, generally expressed as a percentage.
Overcut: The annular space between the excavated borehole and the
outside diameter of the pipe.
PACP: Pipeline Assessment Certification Program by NASSCO.

Panel lining: Panel lining is a modified sliplining method. The shape of
the culvert is covered by preparing panels and fitting them to the culvert.
It can be used to structurally renew large diameter pipes. This method
can accommodate different shapes.
PE: Polyethylene; a form of thermoplastic pipe.
pH: A measure of the acidity or alkalinity of a solution. A value of seven
is neutral; lower numbers indicate more acidity.
Physical pipe inspection: The crawling or walking through manually
accessible pipe lines. The logs for physical pipe inspection record
information of the kind detailed under television inspection. Manual
inspection is only undertaken when field conditions permit this to be
done safely. Precautions are necessary.

Piercing tool: Similar to closed-face pipe ramming, but for small diameter
(2 to 6 in.) boring; used for cable installations under roadways.