Cath-Tech International Ltd
Specialist Pipeline Surveyours and Equipment Suppliers
Cath-Tech International Ltd
DCVG survey in process
DCVG is a method developed to determine and evaluate the condition of pipeline coatings. As the coating is the prime corrosion defence mechanism it is important to be able to assess its effectiveness particularly in situations where the status of the secondary corrosion prevention system (the Cathodic Protection system) is in question.
A common method uses a highly accurate and multi ranged centre zero voltmeter in conjunction with current interrupters to measure voltage gradients in the soil along the pipeline route. Localised changes in measured gradients indicate increased current flow and by deduction this usually means a coating defect is present. The accuracy of the instrument and the skill of the operator allows detailed investigation of the location and the collected data can be interpreted to categorise many defects along the route and prioritise on coating repairs.
