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Over 10,000km of CIPS survey completed in the last 10 years and 25 successfully completed projects


also known as Close Interval Survey (CIS), is an above ground, non-intrusive survey used to accurately determine the effectiveness of a cathodic protection system along the entire buried or immersed length of a pipeline or pipework. 

This assessment is in accordance with national, international and industry standards (AS/NZS, CSA, ISO, AMPP) using recorded pipe-to-soil/water potential measurements against recognized potential measurement acceptance criteria. The CIPS survey technique is applicable to buried and immersed pipelines. 

Onshore Pipelines

Pipe-to-Soil potentials measured at permanently installed test points  often spaced at 1-kilometer intervals along the pipeline do not accurately consider the Pipe-to-Soil potentials along the entire route or between test points.

When performing a close interval potential survey incorporating GPS location, pipe-to-soil potentials are measured at intervals of between 1-3 meters, providing an accurate Pipe to Soil potentials profile for the entire pipeline length. A connection to the pipeline at an above ground test station via a trailing insulated copper wire mounted on a reel carried by the surveyor connected to a high input impedance voltage datalogger equipment the surveyor operates. Portable reference electrodes wired to the datalogger are then placed at known spacing across the top of the pipeline to obtain the Pipe to Soil potential readings.

Pipe-to-soil potentials measurements when cathodic protection current is applied are termed ‘On’ Potentials’.  ‘On’ Potentials are effected by the cathodic protection current flow creating a measurement error known as the ‘IR’ error, derived from Ohm’s Law: V = I x R volts. ‘IR’ errors become  reduced if all sources of cathodic protection current flow on  the pipeline are synchronously interrupted/disconnected with the pipe-to-soil measurement taken immediately after the currents have stopped flowing.  These interrupted/disconnected current flow readings are called ‘Off’ Potentials.

Upon completing the survey collected data is displayed graphically in a plot of potential against distance with notes added as required.

Marine / Offshore Pipelines

Offshore pipelines are typically sacrificial anode systems which are directly welded or connected to the pipeline and synchronous interruption/disconnection cannot be performed so that ‘Off’ Potentials cannot be obtained.  Some international Standards give potential criterion based on “On” Potentials only and it should be noted that where the pipeline is immersed in low resistivity seawater or seabed sand the IR error is equally low and or reduced.

The method of survey is similar to the that for  onshore pipelines, with a reel mounted trailing cable (located on the rear of a survey boat) connected to the pipeline onshore and to  data logging equipment on board. The Reference electrodes, using long cable tails are towed in the water behind the boat and immediately above the pipeline connected to the data logger on board.

JST Associated Surveys

Close Interval Potential Survey (CIPS) > Direct Current Voltage Gradient (DCVG) > Pearson Surveys > Soil Resistivity and pH 

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