The renovation technique of trenchless pipe replacement includes: cement mortar lining, cipp lining, close fit lining, deformed pipe lining, epoxy spray lining, sliplining, spirally wound lining, tight-in-pipe short pipe relining, swagelining and rerounding.
CEMENT MORTAR LINING
Cement mortar lining is the application of a cement mortar (typically about 4mm thick) to the inside of pipelines to protect against corrosion.
Cipp lining (lining with cured in place pipes) is a renovation technique consisting of the insertion of a flexible tube of fibrous matrix, filled by a thermosetting resin, into a water main to produces a structural pipe when cured.
CLOSE FIT LINING
Close fit lining is a technique for pipeline renovation, in which the cross section of the liner is temporarily deformed before insertion into the carrier pipe. The different types of close fit lining systems are: deformed pipe, die drawing or swagelining and rolldown.
Deformed pipe is the alternative to reducing the diameter of the liner to deform it or fold it to enable it to be inserted into the carrier pipe.
DIE DRAWING OR SWAGELINING
Die drawing or swagelining, involves the reduction of the diameter of the liner by heating and pulling it through a tapered steel reducing die which squeezes it until its diameter has been reduced.
Rolldown process is where the diameter of the liner is semi-permanently reduced before it is inserted into the carrier pipeline.
DEFORMED PIPE LINING
Deformed pipe lining is used for the installation of the liner into the host, and includes:
compact pipe, subline system, subcoil system and thermopipe.
In this system PE pipe is factory extruded in a ``C`` shape and coiled onto a drum and pressurized with steam, which rounds the liner, to form a close fit within the host pipe.
The subline system involves the folding of thin walled polyethylene (PE) into a U shape to create a clearance for the installation of the PE pipe into the host pipe, which is then pressurized to snap the bands allowing the liner to revert back to its original shape.
In the subcoil system PE pipe is factory folded into a ``U`` shape, held by a continuous sleeve and then coiled onto a drum. The folding creates a reduction in diameter, giving clearance for installation of the liner.
Thermopipe is a circular woven, high tensile polyester reinforced, polyethylene lining system which is semi-rigid when cool, but once pulled into the pipe, inflated and heated, it becomes flexible and expands, providing structural lining.
EPOXY SPRAY LINING
Epoxy spray lining is a method of lining pipes with a thin lining of resin (typically 1mm thick), which is sprayed onto the surface of a cleaned main and isolate the host pipe from the conveyed medium.
Sliplining is the technique by which a continuous or discreet pipe is inserted within existing pipes.
SPIRALLY WOUND LINING
Spirally wound lining consists of a plastic strip spirally or helically wound to form a continuous lining and does not require special road openings to accommodate variations in cross section and large radius bends.
TIGHT-IN-PIPE SHORT PIPE RELINING
Tight-In-Pipe short pipe relining (TIP-method) allows short sewage pipes to be installed trenchlessly from manhole to manhole, reducing the necessity for filling the annulus.
In the swagelining and die drawing method, close fit thermoplastic pipe lining systems are achieved by stretching a liner pipe by pulling it through one or more dies, to produce a temporary reduction in its diameter. It includes:
Rolldown is the technique where close fit thermoplastic pipe lining systems are achieved by pushing a liner pipe by pulling it through one or more sets of rollers, to produce a temporary reduction in its diameter.
Rerounding, carried out prior to renovation of a pipeline, consists of the insertion of expansion devices or mechanical props to restore a deformed pipeline to its original shape.