DC Voltage Gradient Survey   (DCVG)

Coatings and cathodic protection are relied upon for corrosion control on underground pipelines.  The coating is the primary barrier with the cathodic protection providing back-up protection.  Increasing coating deterioration results in a greater demand upon the cathodic protection system.  Coating breakdown occurs virtually from the day the pipeline is installed due to man-made or environmental factors.  Increasing cathodic protection current outputs will not necessarily provide the desired protection, indeed, in some instances the problem can become more acute due to over-protection and subsequent cathodic disbondment.

Developments in pipeline coating surveys over the last 20 years have led to an increased use of DC methods as an alternative to the Pearson type AC technique.  In Australia and New Zealand the DC voltage gradient survey method has been established as the preferred technique.  Close interval potential surveys have been popular in past years in some countries due to their superior results over the Pearson method and unavailability of DC voltage gradient survey technology.

PCS-2000 meets the requirements for equipment in NACE RP0502-2002  section 6.

NACE Standard

Recommended Practice

Pipeline External Corrosion

Direct Assessment Methodology

The PCS-2000 DCVG meter is capable of operating in all conditions and can cover between 10 and 18km per day.