Surveys
From surveys and asset management, Allied Corrosion Industries’ field-proven specialists are fully trained and operator qualified in the technology of taking and efficiently recording a full suite of surveys and testing.
Interference Testing
Interference current comes in two basic categories: AC interference sources and DC interference sources. Both categories of interference current damage the pipeline. Allied Corrosion’s field specialists have extensive experience in identifying interference problems, along with providing the correct mitigation solution. Identifying stray currents, whether static or dynamic, is a key step in preventing stray current corrosion and extending the life of your asset.
Potential Surveys
Potential Surveys are used to predict corrosion, especially when used in conjunction with other surveys, such as soil resistivity. Potential surveys record pipe-to-soil potentials across the pipeline at regular intervals. Those potentials that are less negative than the negative potential of 850 mV as measured with an copper-copper sulfate reference electrode, the greater the possibility of corrosion. Allied Corrosion Industries, Inc., routinely performs a full suite of potential surveys, and are the first choice for pipeline owners/operators.
Gradient Surveys
Gradient Surveys are used primarily to assess the integrity of the pipelines’ coating. Corrosion can only occur where bare metal is in direct contact with the electrolyte (soil, water, etc). A coating defect is referred to as a “holiday”. Hence, all pipeline corrosion only occur only where coating holidays exist. The gradient survey allows the technician to locate holiday locations to include a relative size of the holiday. Using the gradient survey data along with the corresponding potential survey pipeline, allows the technician to classify the severity of the corrosion activity at each holiday location. This allows the pipeline owner the ability to prioritize and categorize the order in which holiday areas should be inspected.
- DCVG – Direct Current Variation Gradient Survey
- ACVG – Alternating Current Gradient Surveys