DCVG Survey - A Beginner's Guide [Part 1]

Direct Current Voltage Gradient [DCVG] Survey


This non-intrusive, above ground survey allows the operator to identify the location of coating defects (holidays).

We are pleased to announce the first uploaded animation to our YouTube channel (shown within this post).

The YouTube video represents the first instalment within a series. Its purpose is to give an introductory overview to people not familiar with the technique e.g. asset owners, operators, supervisors.

Recognition within International Standards for Buried Pipelines

The technique is an approved ECDA (External Corrosion Direct Assessment) method as detailed in ANSI / NACE Standard Practice SP 0502-2010.

DCVG is also listed as an above-ground survey used to assess the coating condition and to locate coating defects within:

  • BS EN 13509:2003 - Cathodic protection measurement techniques
  • BS EN ISO 15589-1:2017. Petroleum, petrochemical and natural gas industries. Cathodic protection of pipeline systems. On-land pipelines

All DCVG surveys should be undertaken by competent and qualified personnel in accordance with BS EN ISO 15257:2017 - Cathodic protection - Competence levels of cathodic protection persons.


This short animation shows the technique to be utilised for a DCVG (Direct Current Voltage Gradient) survey using an analogue voltmeter and matched electrodes.

The video covers the basic methodology in identifying, centering and measuring coating defects (holidays) in the field [OL/RE Potential]

This "How To" guide is intended for asset owners, operators and supervisors that may not be familiar with the technique.