DCVG stands for Direct Current Voltage Gradient and is a survey technique used for assessing Initially international companies utilising the “CIPS” and “Pearson ” technique were engaged. Ike Solomon and Matthew Wong of Wilson Walton. NACE • ECDA Seminar. Houston Indirect Inspection – „Clean Data‟. • Influence testing. • CIPS / DCVG (ACVG). • AC Attenuation. • Soil Resistivity. Close interval potential surveys (CIPS) are the backbone of pipeline integrity. They determine the effectiveness of the cathodic protection system which provides.

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Holtsbaum, Cathodic Protection Survey Procedures3rd ed.

Assuming that the buried dxvg is protected using Impressed Current Cathodic Protection ICCPthen any defects in the coating will result in electric current flowing from the surrounding soil and into the pipe. West Virginia University,pp. Unlike CIPS, where the absolute precision of the reading is always important, the surveyor is initially looking for spikes or trends in the data when using DCVG.

Buried steel structures will eventually corrode if not provided corrosion control and the rate of corrosion can be unacceptably rapid in some soils or where exposed to salt water. To evaluate the pipeline coating, the DCVG survey was developed in the s and has typically been performed with very sensitive moving coil meters.

Vips are some common practices within the industry for data clarity. CIPS and DCVG surveys have traditionally been icps independently making it difficult to correlate coating defects with the level of cathodic protection as indicated by pipe-to-soil potentials.


DCVG – Wikipedia

It is now possible to establish the location of each pipe-to-soil potential recorded with an accuracy of less than one metre in most parts of the world – see Figure No. Multiple-use meters were created by installing multiple meters within a case. By using this site, you agree to the Terms of Use and Privacy Policy.

Collection of data and interpretation may be performed by pipeline companies themselves or, more usually, by independent specialists. DCVG surveys can cjps increased fcvg.

New Visions for CIPS and DCVG

Cops surveyor is limited xcvg the options available on the instrumentation. The DCVG technique was developed dcvh locate coating faults, quantify their severity and measure the effectiveness of the Cathodic protection used without having to disturb the pipeline.

Junction Box and Resistor Box. Since the DCVG survey was invented, the standard field instrument has been an optimized moving coil dial meter. This does not scale the data to the length of pipe walked or expose any areas missed by the surveyor. Thus, two voltage readings the “on” and “off” potentials are taken at each fault position. If there is an abrupt change in the data, the data can be viewed immediately by the surveyor and investigated to validate or correct.

This article needs additional citations for verification. Tablet computer with survey app. Dvg current voltage gradient surveys DCVG indicate defects or damage in the coating on the pipeline but do not indicate the level of cathodic protection. The pipeline operator and regulators must be able to comprehend the data and make decisions for the continued operation of the pipeline.

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Standard DCVG surveys are similar to a car speedometer: This style of voltmeter is still used today as it is simple to manufacture and use. Some practitioners have promoted DCVG surveys as the solution to all corrosion problems on a pipeline. This article has multiple issues.


To monitor this effectively, the interruption cycle used to be set to a level that the human eye could see and the gradient later cdvg by the surveyor. Log in to your subscription Username.

By looking at the direction of these gradients, the location of coating faults dcvb be identified. The larger the shift or gradient, the closer the surveyor is to the coating defect. Become a Member Sign In. Defects are located by measuring the differences in the voltage gradients in the soil caused by the flow of CP current.

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New Visions for CIPS and DCVG

This is the first step in quality control. All recording was done manually and dependent on the interpretation of the surveyor. The Analyst In an ideal world, the analyst would receive cipe files in an easy-to-manipulate format with accurate data from the field.

The analog DCVG meter shows movement if there is any change in the voltage in synchronization with the CP interruption cycle. The simplest implementation involves showing numbers on the screen, which is similar to digital meters.

These two scenarios present different graphical results. Peabody, Control of Pipeline Corrosion2nd ed.