Iplex has a notable history of producing pipes suitable for trenchless installations, either as new pipelines or for the rehabilitation of existing water and sewerage systems. The company was one of the inaugural members of the Australasian Society for Trenchless Technology, and some examples of seemingly intractable civil engineering problems solved by Iplex are described here.
Iplex pipes for slip lining renovation work
For larger diameters
Flowtite GRP Pressure & Non pressure Pipes
(DN 3000)
For smaller diameters
PVC Non Pressure Pipes ( DN 50 to DN 575)
PE Pressure Pipes ( DN 20 to DN 1000)
C-Liner (DN 80 to DN 300)
Examples of major slip lining projects can be found in the inner suburbs of Sydney. The Sydney Water Corporation has been renovating old "man-entry size"
cast iron trunk mains installed over a century ago as in many cases these have reached the end of their economic life. GRP pressure pipes with the standard Plexiseal
couplings have been inserted inside the old mains with minimal traffic disruption to the congested roadways over the pipe alignments. Well known Sydney thoroughfares
such as Elizabeth Street in Redfern, Cleveland Street in Darlington, and Oxford Street in Paddington now have a combined total over 6 kilometres of rehabilitated water
mains where large diameter GRP pressure pipes have been used.
In smaller diameters, POLIplex polyethylene pipes are frequently employed for slip lining heavily corroded "non man-entry" cast iron water mains and cracked vitrified clay sewers. Where the internal diameter of the renovated pipeline has had to be the same or greater than the old pipes, pipe bursting techniques have been used. By the insertion of a diesel Impact hammer the old pipe is split open over the whole length to create sufficient space for the replacement pipe. The use of polyethylene pipe of sufficient wall thickness ensures there is adequate structural strength without the need for grouting around the pipe.
To facilitate sliding, small bore polyethylene pipes are welded longitudinally at intervals around the circumference to act as skids. This method was used for a DN 600 sewer at Coburg in Melbourne and river intake pipeline at Rydalmere in Sydney.
C-Liner is a "folded" PE pipe liner which is manufactured by Iplex for Thiess Environmental Services. This pipe is inserted in an existing pipeline and rerounded using steam pressure. C-Liner is a close fitting liner which minimizes the reduction in cross-sectional area after the renovation and is used to restore the integrity of leaking or cracked sewers. The maximum diameter where this method is practicable up to DN 300.
This pipe is an alternative to PVC in diameters up to DN3000 when either pressure or non-pressure slip lining pipe is required.
The telecommunications industry in particular uses large quantities of polyethylene conduit installed as cable duct. Iplex currently holds the Telstra contract for supply of these pipes and in recent years drillers for this industry have been active in most major Australian cities. The technique is used under roads, railways, waterways, and environmentally sensitive areas. While conduit is usually small in diameter, watermains of sizes of DN 800 and larger have also been installed by this method.
