Why Pipeline Rehabilitation
Where the performance of the pipeline is unsatisfactory but the fabric has a residual value, either structurally in its own right or as a lining support, rehabilitation is the solution.
An essential preliminary is to determine the condition of the existing pipeline. From hydraulic analysis and structural inspection using CCTV where it may be concluded that a pipeline is:
Structurally weak or;
Structurally sound, but hydraulically defective.
In either case it is more economic, environmentally friendly and non disruptive to rehabilitate the defective pipe than to excavate and replace.
Our specialized unit Kurtec Pipeline Services (KPS) offer a comprehensive range of rehabilitation techniques based on “Trenchless Technologies”
Our services include;
The structural condition and hydraulic capacity of an existing conduit determines the type of rehabilitation technique required. Thus, when there is doubt concerning the condition of an underground network, it is important to carry out a CCTV survey. The interpretation of the visual record can then be developed into a mapping of the entire pipeline.
It is essential that prior to any renovation process the pipeline must be cleaned of any deleterious material and debris.
Typical cleaning methods are mechanical/hydro pigging and hydro-jetting.
This is a well tried and tested technique for applying either an anti-corrosion or structural lining to pipes.
Cement Mortar Lining has been used for lining water mains from 75mm diameter upwards, to prevent encrustation, discoloured water and loss of capacity as well as structural reinforced linings on larger diameters.
Sliplining was one of the earliest forms of continuous structural lining processes. A new pipeline of smaller diameter is inserted into the defective pipe and the annulus grouted. It has the merit of simplicity and is relatively inexpensive. However, there can be significant loss of hydraulic capacity and grouting requires special care.
This has been overcome with the development of Subcoil & Subline which is installed by KPS to provide close fit interactive lining of water mains. It consists of a close fit, thin wall PE pipe, which has been folded and sleeved or taped to shape in the factory or at site. The external diameter of the folded pipe is typically about 80% of the ID of the pipe within which it will be installed.
It is installed into the host pipe by winching it into place. This followed by pressurisation, which splits the sleeve or tapes and reverts or re-rounds the liner into a close fit with the host pipe.
When improved hydraulic performance is taken into account, it is sometimes found that there is little or no loss of capacity.
Cured in Place Pipe
This structural renovation system involves a resin impregnated liner being inserted into the pipe or conduit (not necessarily circular) and subsequently forced against the pipe wall using water pressure to provide a continuous lining.
Curing of the resin may occur naturally or by heating the inversion water to form a resilient tight fitting lining. Any lateral connections are reopened on completion and there is little loss of capacity. The system can accommodate larger radius bends and is used from 100mm diameter upwards.
Localized Repairs (Gravity Systems)
Where local defects may be found in an otherwise sound pipeline, this could be due to point pressure loading causing cracking or individual joint failure it is possible to repair with a localized repair.
Localized repairs can also be used in conjunction with other linings to repair the localized defect and protect the rest of the pipe with a low cost protection system.
Where the survey shows that the pipeline is beyond repair or the system requires the line to be upsized the client has no option but to replace the pipeline. This can be done by open cut with all the associated costs and disruption or burst the existing pipeline whilst pulling in a new pipeline in its place. Pipebursting is one of the most economical ways to replace a buried pipeline. The direct costs are lower than the traditional costs of dig-and-replace method, but when pipes are buried under other structures or other services the cost are very low and in some cases the only the answer to replacement. When time, disruption and restoration are taken into account Pipebursting is the only logical way for pipe replacement.