Services / Close Interval Survey


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 often an integral part of an External Corrosion Direct Assessment (ECDA) program.

CIS Helps Identify:

  • Polarized potentials along the pipeline
  • Pinpoint areas of low/sub criterion protection
  • Identify specific areas experience DC stray current interference
  • Measure CP current in pipeline in survey areas
  • Identify magnitude and direction of stray current
  • Obtain native potentials (via a depolarization survey)