Slip lining is perhaps the oldest of all trenchless techniques.
It involves the insertion of a new pipe into an existing pipe.
Under the right conditions, slip lining is also the simplest
trenchless technique. A new pipe with an outside dimension
smaller than the inside dimension of the host pipe is either
pulled or pushed into the host pipe. The ideal host pipe for
slip lining are straight with no deformities, that is pipes with
no or modest bends, no severe protrusions into the pipe, and
only modest offset joints. Slip lining may be continuous or
segmental. Polyurethane (HDPE and PE) and polyvinyl chloride
(PVC) pipes are most commonly used for continuous slip lining
circular, non-man entry pipes. The new pipe is laid out above
ground and pulled through an excavated pit into the host pipe.
The new pipe is then winched through the host pipe to an exit
pit or manhole. In situations where space for layout of the pipe
above ground is limited, the new PE or PVC pipe can be butt-
fused during the installation proc