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Sacrificial Anode Cathodic Protection (SACP)

Sacrificial Anode Cathodic Protection (SACP)

Sacrificial Anode Cathodic Protection (SACP) is a technique uses the natural structural differences between two metals in an enviornment to provide a driving voltage. This voltage creats a current that ensures the corrosion occurs on the anode 'sacrificing' itseld protecting the main structure from corrosion. Sacrificial anodes are very active metals most commonly zinc, aluminium and magnesium.

 

Usually SACP methods have been found to be more effective in small well coated, low current demand structures. However in difficult areas such as offshore work where structure may not have coatings, sacrificial anodes can easily be installed without the need of a power source providing the required protection.

 

For applications such as marine structures the anode size must be determined by the requird lifetime, generally 15-20 years. The anode can be directly mounted (welded) onto the structure. If this is not possible the anode can be connected by cable. Moitoring is also possible by using reference electrodes using a multimeter.

 

Although Impressed Current Cathodic Protection (ICCP) is generally the prefered method for long overground pipelines SACP can still be used. Two methodes involve either installing anodes every few hundred meteres or by using ribbon anodes installed with the pipe along the entire length. Ribbon anodes are magnesium or zinc. Being able to monitor the CP effectiveness is an important aspect for our clients therefore the anodes are connected to pipeline using a junction box above ground.

 

Please get in contact with OTDS with your cathodic protection requirements by sending us an email enquiries@otds.co.uk.

Benefits

  • No power source required
  • Simple to install, operate and maintain
  • Additions easily installed
  • Less interaction with neighbouring structures

Applications

  • Used where soil or water resistivities are low
  • Small surface areas of protected structure
  • Where power source difficult to install - marine structures