Quantum CIPS and Analogue DCVG have been designed to work together as a one pass survey using two different ( as required by ECDA ) but compatible techniques with a direct relationship to a pipelines basic corrosion mitigation techniques, the Protective Coating and Cathodic Protection. However, analogue DCVG can be used to assist other methods of inspection.

The combination of different technologies in the search for metal loss areas has distinct benefits in improving the cost effectiveness of the inspection techniques and enhancing the quality of the data recorded. From past work comparing DCVG coating fault locations with Inline Inspection metal loss pig data we know that more than 83% of all metal loss tool indications occur at coating faults. Hence using DCVG to direct two new above ground technologies, the best information on the integrity of the pipelines can be determined. These newer techniques are Guided Wave Ultrasonics and No Pig Technology. Using DCVG to identify and characterise the coating faults first it is possible to direct these two technologies to the most likely locations for metal loss for their confirmation. It has to be remembered that most coating faults do not have metal loss, the CP doing its job. Hence the two new techniques can then be applied to help distinguish those faults that do have metal loss.

Guided Wave Technology.
Guided Wave Technology uses a low frequency ultrasonic tool that is clamped onto the pipeline and can detect corrosion (metal loss ) up to 30 metres in either direction. This method obviously requires the pipe to be exposed and coating removed in the small bellhole where the tool is clamped on. Using a coating fault for the excavation and concentrating in areas identified by DCVG to have a high density of faults particularly in low soil resistivity areas, maximum benefit can be obtained from the technology.

No Pig Technology.

When the frequency of an electrical AC current which flows through a conductor (the pipeline) is increased, it tends to move from the body of the conductor to concentrate just below its surface. For different AC frequencies the magnetic field generated is monitored above ground and variations (distortions) of the magnetic field indicates wall thickness reduction of the pipeline, ie a metal loss areas. From various measurements it is possible to evaluate quantitatively the percentage of wall thickness loss. DCVG can direct where to pay most attention to any distorting magnetic field indicating metal loss.
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