The cooling water pipelines vary in diameter from 25 mm to 600 mm with buried sections of between 8.75 m and 83.65 m. The total surface area to be protected was 426 square metres. Soil resistivity testing, undertaken to enable the design to be prepared, showed the ground to have a relatively high resistance of 80,000 ohm cm. As the design life required was a minimum of 50 years and the pipelines were to be laid in a congested area in high resistance soil, a conservative design approach was adopted.

The decision was made to install an ICCP system using distributed anodes with the anodes running parallel to, and a short distance away from, the pipelines being protected.

The anodes used are a special unit comprising a 3.175 mm diameter titanium wire coated with platinum group metal oxides and encased inside a 100 mm diameter ‘sock’ containing a high quality, low ash carbonaceous backfill. As the titanium wire has a high electrical resistance it is paralleled by a copper cored conductor, which is connected to the titanium approximately every 10 m, ensuring uniform distribution of the protective current. Each anode is manufactured individually with a length to suit the pipe run.

Positive DC power to the anodes is supplied by a transformer rectifier unit located adjacent to the electrical switch room. The T/R unit is fitted with a constant current control to cater for the changing soil resistivity, which may be affected substantially by the weather.

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Individual negative connections from the transformer rectifier unit were made to the six pipelines to complete the cathodic protection circuit. Monitoring of pipelines terminated in three test points at the extremities of the pipeline runs.

To maximise protection on the pipelines, all buried sections are isolated from above ground pipe work using insulating flange kits and fittings.

Commissioning was undertaken in accordance with Australian Standard AS2832.2-2003. The test results confirmed all buried sections to be fully protected with potentials at all locations being more negative than –0.85 volts with respect to copper/copper sulphate. The low current required to achieve protection was 113 mA at 2 volts, a particularly pleasing result.

Savcor Products makes cutting and bevelling pipe easy when using the latest pipeline machinery supplied by E.H. Wachs Company. All machines are engineered to a high quality including ISO 9001-2000 manufacturing standards.

Reliability is assured, with Wachs having over 120 years of experience in engineering and manufacturing. Wachs first started selling pipe cutting machinery in 1949 and since then, Wachs has continued to design and develop cutting machines based on reliability and the need to fit customer requirements. The complete range of Wachs equipment can be viewed at savcorproducts.com.au

Contractors have a variety of machines to choose from, not only for above ground works, but underwater sub-sea conditions as well.