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Cathodic protection

Cathodic protection (CP) is a technique to control the corrosion of a metal surface by making that surface the cathode of an electrochemical cell.

It is a method used to protect metal structures from corrosion. Cathodic protection systems are most commonly used to protect steel, water/fuel pipelines and storage tanks; steel pier piles, ships, offshore oil platforms and onshore oil well casings.

A side effect of improperly performed cathodic protection may be production of molecular hydrogen, leading to its absorption in the protected metal and subsequent hydrogen embrittlement.

 Cathodic protection
Aluminum anodes mounted on
steel structure
Cathodic protection is an effective method of preventing stress corrosion cracking.
Testing

Electrochemical potential is measured with reference electrodes. Copper-copper(II) sulfate electrodes are used for structures in contact with soil or fresh water. Silver-chloride electrodes are used for seawater applications.

The company provides surveys for operational and in construction structures as follow:		 Testing
CIS / DCVG

Soil or Water resistivity - for gaining CP system design basic parameter
Insulators or continuity check
Native (Baseline) potential of a structure (Offshore or Onshore) - Neccesary for future asssesment of the effectivity of a CP system. This survey is done before secrificial electrodes are mounted
Close Interval Potential Survey (CIS) - is usde to determine if adequate cathodic protection is achieved at all points along the structure.
Direct Current Voltage Gradient Survey (DCVG) - is used for Cathodic protection current pick up at coating holidays (small pits)