Corrosion Inspection & Cathodic Protection Assessment
we help port operators, terminal owners and industrial clients identify corrosion risks, assess the effectiveness of existing protection systems and recommend practical measures to extend the service life of critical marine infrastructure.
Corrosion Inspection & Cathodic Protection Assessment
Corrosion Inspection & Cathodic Protection Assessment is a critical asset integrity service designed to evaluate, monitor and control corrosion in port and marine structures exposed to aggressive salt-water environments. In ports, structures such as steel piles, quay walls, jetties, piers, dolphins, sheet piles, mooring systems, pipe supports, access platforms and submerged steel components are constantly exposed to seawater, humidity, oxygen, marine growth, tidal action and chloride attack.
Over time, these conditions can reduce steel thickness, damage protective coatings, expose reinforcement, weaken connections and compromise the structural capacity of port assets. PIANC specifically addresses the inspection, maintenance and repair of maritime structures exposed to material degradation caused by salt-water environments, making corrosion control a key part of port infrastructure integrity management.
Purpose of Corrosion Inspection
The main purpose of corrosion inspection is to determine the current condition of metallic and reinforced concrete elements and to understand how corrosion is affecting the safety, durability and performance of the structure.
In marine environments, corrosion does not affect all areas equally. The splash zone, tidal zone, submerged zone and atmospheric zone may experience different corrosion mechanisms. For example, steel elements in splash and tidal zones often suffer accelerated deterioration due to repeated wetting and drying, oxygen exposure and chloride contamination.
This inspection helps answer important questions such as:
- Is the structure losing thickness due to corrosion?
- Are steel piles, beams or plates still within acceptable limits?
- Are coatings still protecting the structure effectively?
- Is the cathodic protection system working properly?
- Are sacrificial anodes consumed or missing?
- Is there a risk of accelerated corrosion in hidden or submerged areas?
- Are repairs, recoating, anode replacement or structural strengthening required?
What Is Cathodic Protection Assessment?
- Cathodic protection assessment is the evaluation of a corrosion control system designed to protect metallic structures in conductive environments such as seawater, soil or wet concrete. AMPP describes cathodic protection as a critical corrosion mitigation method used across assets such as fixed offshore structures, pipelines, storage tanks, ships and similar infrastructure.
- In marine structures, cathodic protection is commonly achieved through:
1. Sacrificial Anode Cathodic Protection
This system uses more active metals, such as aluminium or zinc anodes, which corrode preferentially to protect the main structure. DNV’s recommended practice for cathodic protection design specifically addresses aluminium and zinc-based galvanic anodes for cathodic protection design and installation.
2. Impressed Current Cathodic Protection
This system uses an external power source to deliver protective current to the structure. It is often used for larger or more complex marine assets where sacrificial anodes alone may not provide sufficient protection.
AMPP notes that cathodic protection in seawater structures can be achieved using either sacrificial galvanic anode systems or impressed current systems.
Structures Covered
TechInspecta’s corrosion inspection and cathodic protection assessment can be applied to:
- Steel piles and tubular piles.
- Sheet pile quay walls.
- Jetties, piers and dolphins.
- Mooring dolphins and breasting dolphins.
- Steel decks, beams, bracing and support frames.
- Crane rails, crane beams and steel support structures.
- Bollards, quick release hooks and mooring hardware.
- Fender panels, chains, brackets and anchor bolts.
- Pipe racks, pipe supports and jetty pipelines.
- Access platforms, ladders, walkways and handrails.
- Submerged steel structures and underwater components.
- Reinforced concrete structures affected by chloride-induced corrosion.
Scope of Corrosion Inspection
Visual Corrosion Survey
A detailed visual inspection is performed to identify visible corrosion, rust staining, coating breakdown, pitting, scaling, delamination, section loss, deformation, marine growth and damage to protective systems.
This includes inspection of exposed steelwork, splash-zone elements, tidal-zone components, connections, welds, bolts, anchor plates, access structures and safety-critical attachments.
Coating Condition Assessment
Protective coatings are inspected to determine their condition and remaining effectiveness. ISO 12944-5 provides guidance on paint systems commonly used for corrosion protection of steel structures, including selection of paint systems for different environments and surface preparation grades.
The coating assessment may include checking for:
- Blistering.
- Peeling.
- Cracking.
- Chalking.
- Rust breakthrough.
- Mechanical damage.
- Poor adhesion.
- Coating thickness deficiencies.
- Exposed steel areas.
Ultrasonic Thickness Measurement
Ultrasonic thickness measurement may be used to determine the remaining wall thickness of steel piles, plates, beams, pipes and other metallic components. This is especially important where corrosion is suspected but section loss cannot be accurately estimated by visual inspection alone.
Pitting and Localized Corrosion Assessment
Pitting corrosion can be more dangerous than uniform corrosion because it may create deep local defects while the surrounding steel appears acceptable. TechInspecta assesses pitting depth, distribution, severity and potential impact on structural capacity.
Inspection of Bolts, Welds and Connections
Connections are often highly vulnerable to corrosion because they contain crevices, gaps, contact surfaces and areas where water and contaminants can accumulate. Inspection may include weld condition checks, bolt corrosion assessment, anchor bolt verification and evaluation of base plates or brackets.
Reinforced Concrete Corrosion Assessment
For reinforced concrete port structures, corrosion inspection may include checking for rust staining, cracking, spalling, delamination, exposed reinforcement, chloride contamination indicators and areas of concrete cover loss. These signs may indicate corrosion of reinforcement and possible loss of durability or structural performance.
Cathodic Protection Assessment Scope
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Anode Condition Inspection
Sacrificial anodes are inspected to determine whether they are still active, properly connected and capable of providing protection. This includes checking:
- Anode consumption level.
- Missing or detached anodes.
- Poor electrical connection.
- Physical damage.
- Uneven consumption.
- Incorrect anode placement.
- Remaining estimated anode life.
Potential Measurement Survey
Potential measurements are taken using suitable reference electrodes to determine whether the structure is receiving adequate protection. ABS guidance notes state that cathodic protection controls corrosion by supplying direct current to the immersed surface, making the structure the cathode of an electrochemical cell.
For carbon and low-alloy steel in aerated seawater, ABS guidance notes reference a commonly accepted protection criterion of –0.80 V or more negative versus Ag/AgCl/seawater reference electrode, with different considerations for certain anaerobic conditions and material limitations.
Continuity Testing
Electrical continuity is important for cathodic protection performance. If parts of the structure are not electrically continuous, some areas may not receive protective current. Continuity testing helps confirm whether piles, braces, frames, plates, anodes and other metallic components are properly connected.
Impressed Current System Inspection
For impressed current cathodic protection systems, inspection may include checking rectifiers, cables, junction boxes, reference electrodes, anode beds, current output, voltage output, alarms and system records.
CP System Performance Review
The overall performance of the cathodic protection system is reviewed to determine whether it is under-protecting, over-protecting or operating within acceptable limits. Over-protection may also create risks for certain materials, coatings or high-strength steels, so interpretation must be done carefully by competent personnel.
ISO 15257 defines competence levels for people working in cathodic protection, including survey, design, installation, testing and maintenance, with application sectors including marine metallic structures.
Key Benefits to the Client
Corrosion Inspection & Cathodic Protection Assessment helps clients protect their port assets, reduce long-term maintenance costs and avoid unexpected failures.
Main benefits include:
- Early identification of corrosion damage.
- Confirmation of cathodic protection effectiveness.
- Extension of asset service life.
- Reduction of structural failure risk.
- Better planning of maintenance and repair budgets.
- Improved safety for port personnel and marine operations.
- Reduced unplanned shutdowns.
- Support for compliance with asset integrity requirements.
- Improved reliability of jetties, quays, dolphins and submerged structures.
- Clear technical basis for repair, recoating, anode replacement or strengthening decisions.
