Impressed current protection systems are widely recognised as a superior or a more controllable alternative to sacrificial anode systems for preventing corrosion. In this guide we will explain what they are, how they work and the different types available to you.
WHAT ARE IMPRESSED CURRENT CATHODIC PROTECTION ANODES?
Impressed Current Protection Anodes, or Impressed Current Cathodic Protection (ICCP) systems, are a method of corrosion protection that uses an external source of electricity to apply a current to the anodes which works to protect a steel structure in a variety of applications, such as a pipelines, steel tower or storage vessels.
These systems are often used when protecting larger structures, or in complex applications where sacrificial anodes cannot economically deliver sufficient current to all parts of the structure requiring protection..
Impressed current anodes can provide a more controllable and long-term solution to a corrosion problem by varying the driving output of individual anodes within an ICCP system. The impressed current system enables the current to be accurately controlled, giving you greater flexibility to match specific corrosion demands than can be found in sacrificial anode systems.
HOW DO IMPRESSED CURRENT CATHODIC PROTECTION ANODES WORK?
Impressed current anodes require an external source of electricity to power the system and thus set up the same type of electrical cell that is found naturally within sacrificial anodes systems. In this process electrons flow from the anode, through the electrolyte (often the soil) and to the cathode (often the pipeline or other protected steel structure).
These anodes can be made a variety of materials, including cast iron, mixed metal oxide (MMO), or graphite. The anode itself can come in many shapes and sizes, such as rods, tubes, wires, plates or even mesh.
The anode is installed within the electrolyte, around the structure to be protected, and connected to the positive terminal, whilst the structure is connected to the negative terminal.
TYPES OF IMPRESSED CURRENT PROTECTION ANODES
We offer two types of impressed anodes: Mixed Metal Oxide (MMO) and Silicon Iron.
Mixed Metal Oxide anodes (MMO), or dimensionally stable anodes (DSA), consist of a rare metal oxide coated onto a titanium substrate. They provide a highly effective corrosion prevention system for various applications and environments, including seawater, brackish water, fresh water, with or without carbon backfill, and also in concrete.
Due to the high stability and low consumption rate of the MMO coating, this type of anode has a much longer lifespan than alternative solutions and provides excellent chemical resistance, especially in acidic conditions.
Silicon Iron anodes, available in both tubular and stick form, are a proven cathodic protection solution commonly used in fresh water, seawater, and both shallow and deep grounded applications.
They are a popular choice for cathodic protection systems due to their low specific resistance, suitability for a variety of applications, proven low consumption rate and dependability.They are a popular choice for cathodic protection systems due to their low specific resistance, their low cost, their proven low consumption rate and suitability to a variety of applications.