Close Interval Survey

Close Interval Surveys (CIS) are completed on buried or submerged pipelines. Pipe-to-soil potentials are taken at regular intervals and are used to determine compliance with NACE SP0169 (-850 mV polarized potential, or 100 mV polarization) standards. CIS surveys are an integral part of an External Corrosion Direct Assessment (ECDA) program.

CIS Helps Identify:

• Polarized potentials along the pipeline

• Areas of low/sub criterion protection

• Areas experiencing DC stray current interference

• CP current in pipeline in survey areas

• Magnitude and direction of stray current

• Native potentials (via a depolarization survey)