What is Cathodic Protection?

Cathodic Protection (CP) is an electrochemical corrosion-control method used to reduce corrosion of metallic structures exposed to soil, water, or other electrolytic environments. It works by making the structure being protected the cathode of an electrochemical cell, reducing the rate at which the metal undergoes corrosion.

At AQMOND, our Cathodic Protection services cover Impressed Current Cathodic Protection (ICCP) and Sacrificial Anode Cathodic Protection (SACP) systems for applications where corrosion can threaten the integrity, reliability, and service life of critical metallic assets.

Cathodic protection is commonly used alongside protective coatings. While coatings provide a physical barrier between the metal and its environment, cathodic protection can provide additional protection at areas where the coating is damaged, deteriorated, or otherwise unable to provide complete protection.

How Cathodic Protection Works

Initial Assessment:

• Asset Inspection:
• The structure is assessed to understand its material, condition, coating system, operating environment, and exposure to potential corrosion mechanisms.
• Environmental Assessment:
• Soil or electrolyte conditions are evaluated because factors such as resistivity, moisture, temperature, and exposure conditions influence cathodic protection requirements.
• Electrical Continuity Assessment:
• The electrical characteristics and continuity of the structure are reviewed to determine how the CP system can be applied and monitored.
• Baseline Measurements:
• Existing structure-to-electrolyte potentials and other relevant electrical measurements can be established before system design or installation.

Cathodic Protection Systems

Impressed Current Cathodic Protection (ICCP)

ICCP systems use an external DC power source to drive protective current from anodes to the metallic structure being protected.

A typical ICCP system may include:

• Transformer-rectifier or other DC power source
• Anode system or anode groundbed
• Positive and negative cables
• Test stations and junction boxes
• Reference electrodes
• Monitoring and measurement equipment

The negative output of the DC power source is connected to the structure, while the positive output is connected to the anode system. The resulting current flow provides the electrochemical protection required by the design.

For larger or longer structures, ICCP can be advantageous where higher and controllable current output is required. The appropriate configuration depends on the asset, environment, coating condition and design requirements.

Sacrificial Anode Cathodic Protection (SACP)

SACP systems use a more electrically active metal, known as a sacrificial anode, which is electrically connected to the structure being protected.

The sacrificial anode naturally provides the protective current and gradually consumes itself instead of the protected structure.

Depending on the application, materials such as zinc or magnesium alloys may be used as sacrificial anodes. SACP systems can be particularly suitable for applications where the required protection current is relatively low and an external power source is not practical or required.

How a Cathodic Protection System is Installed

Design & Engineering:

• Protection Requirements:
• The required level of corrosion protection is established based on the structure, environment, coating condition, surface area, and applicable design criteria.
• System Selection:
• ICCP or SACP is selected based on the characteristics and requirements of the asset rather than applying a single system to every application.
• Anode Design:
• The type, number, location, spacing, and expected service life of the anodes are determined as part of the CP design.
• Monitoring Points:
• Appropriate test stations, reference electrodes, junction boxes, and measurement points are incorporated where required to allow system performance to be assessed.

Installation:

• Anode Installation:
• Anodes are installed in the appropriate location and configuration for the application. For ICCP systems, this may include an engineered anode groundbed.
• Electrical Connections:
• Cables and electrical connections are installed between the power source, anodes, monitoring equipment, and protected structure as required by the system design.
• System Integration:
• The CP system is connected to the protected asset while ensuring appropriate electrical isolation, continuity, and compatibility with existing infrastructure.

Testing & Commissioning

• Electrical Testing:
• Electrical connections, continuity, isolation, cable integrity, and other relevant components are checked before the system is energised.
• Potential Measurements:
• Structure-to-electrolyte potential measurements are taken to assess the effectiveness of the protection system.
• Current Output Verification:
• For ICCP systems, the DC output is adjusted and verified against the requirements of the design.
• System Commissioning:
• The completed system is commissioned under controlled conditions, with operating measurements recorded to establish a performance baseline.

Cathodic protection systems must be controlled carefully. Excessive protection levels can create their own risks, including potential coating damage or other material-related effects, so system performance should be monitored against the applicable protection criteria rather than simply maximising current output.

Monitoring & Maintenance

Cathodic protection is not simply an install-and-forget system. Regular monitoring helps determine whether the system continues to provide the required level of protection throughout its operating life.

• Routine Monitoring:
• Structure-to-electrolyte potentials and other relevant CP parameters are measured at designated monitoring points.
• System Inspection:
• Rectifiers, anodes, cables, test stations, junction boxes, reference electrodes, and other system components are inspected as applicable.
• Performance Assessment:
• Recorded measurements are reviewed to identify changes in system performance, protection levels, or operating conditions.
• Corrective Maintenance:
• Where abnormal readings, damaged components, depleted sacrificial anodes, or other issues are identified, appropriate corrective action can be planned.

Applications

Cathodic protection can be applied to a range of metallic structures where corrosion control is required, including:

• Buried pipelines
• Above-ground and buried tanks
• Water storage systems
• Industrial piping
• Offshore and marine structures
• Pipe supports and structural components
• Other buried or immersed metallic assets

The appropriate CP system depends on the specific asset and environment. For example, engineering guidance identifies SACP as potentially suitable for shorter buried pipeline sections with good coatings and no convenient external power, while ICCP may be more appropriate for longer or larger-diameter pipelines requiring greater controllable current.

Our Approach to Cathodic Protection

At AQMOND Global Investment Ltd, we approach corrosion control as an engineering problem rather than simply installing an anode system.

• Assessment Before Installation:
• We consider the asset, environment, coating condition and protection requirements before determining the appropriate approach.
• Application-Specific Design:
• ICCP and SACP systems have different operating principles and are selected according to the requirements of the specific application.
• Controlled Protection:
• The objective is to provide sufficient protection while avoiding excessive protection levels that could negatively affect the asset or coating system.
• Monitoring & Maintenance:
• Ongoing measurement and inspection help verify system performance and identify when corrective maintenance may be required.

Why Choose AQMOND for Cathodic Protection?

By choosing AQMOND Global Investment Ltd for your Cathodic Protection requirements, you benefit from:

• ICCP and SACP corrosion-control solutions
• Application-specific system assessment
• Protection for pipelines, tanks, piping and other metallic assets
• Installation and commissioning support
• System monitoring and maintenance
• A focus on asset integrity and long-term corrosion control

Our objective is not simply to slow corrosion. It is to help clients protect critical metallic assets, maintain structural integrity, and support reliable long-term operation through appropriately designed and monitored cathodic protection systems.