Page 464 - Trenchless Technology Piping Installation and Inspection

414 App endix D

Bedding: A prepared layer of material below a pipeline to ensure
uniform support.
Bent sub: An offset section of drill stem close behind the drill head that
allows steering corrections to be made by rotation of the drill string to
orientate the cutting head (used in horizontal directional drilling).
Bentonite: Colloidal clay sold under various trade names that form a
slick slurry or gel when water is added; also known as driller’s mud. See
drilling fluids.
Bits: Replaceable cutting tools on the cutting head or drill string.
Bore: A generally horizontal hole produced underground, primarily for
the purpose of installing services.
Boring: (1) The dislodging or displacement of spoil by a TBM; a rotating
auger or drill string to produce a hole called a bore. (2) An earth-drilling
process used for installing conduits or pipelines. (3) Obtaining soil
samples for evaluation and testing.
Boring machine: An automated mechanism to drill earth.
Boring pit: Also entrance pit, launch or drive pit; an excavation in the
earth of specified length, depth, and width for placing the boring machine
on required line and grade.
Bottom inversion: The CIPP tube is inverted through a specially designed
elbow located at the elevation of the pipe, typically in a manhole or
excavated pit.
Breakout: Controls the joint make and/or break mechanism (in HDD
operations).
Burst strength: The internal pressure required to cause a pipe or fitting
to fail within a specified time period.
Butt-fusion: A method of joining polyethylene and PVC pipe where two
pipe ends and are rapidly brought together under pressure to form a
homogeneous bond.
Bypass: An arrangement of pipes and valves whereby the flow may be
passed around a hydraulic structure or appurtenance. Also, a temporary
setup to route flows around a part of a sewer system.
Bypass pumping: Taking all existing flow in a pipe and routing around
the section of pipe to be renewed, replaced, or repaired.

Calibration hose: A flexible hose inverted into a pulled-in liner and used
to hold the resin saturated fabric tube up tight against the existing, old, or
host pipe until final cure has been achieved.

Can: A principal module, which is part of a shield machine as in
microtunneling or tunnel boring machines (TBMs). Two or more may be
used, depending on the installation dimensions required and the presence