No CP Design Is Proven Until It’s Commissioned
A well-engineered Cathodic Protection (CP) system is only as good as its real-world performance.
No CP design, whether sacrificial anode or ICCP, can guarantee adequate protection until it has been installed, allowed to polarise the structure, and properly tested on site. Not even one that has been verified by computer modelling.
That’s where on-site CP commissioning surveys come in.
Commissioning is not a box-ticking exercise. It is the critical step that confirms:
- The system has been installed correctly
- The steelwork is receiving adequate cathodic protection
- The design assumptions are valid in operational conditions
- Long-term corrosion mitigation has been achieved
For asset owners in operational ports, this assurance is essential.
The Challenge: Commissioning in a Live Port Environment
This example involved commissioning a sacrificial anode CP system installed along a sheet piled quay wall within a fully operational harbour.
Recording accurate CP potential readings in a live port presents several challenges:
- Access & Logistics – Coordinating safe access along active quay walls
- Security & Coordination – Working within port authority requirements
- Environmental Conditions – Tides, weather, and marine growth
- Data Management & Reporting – Ensuring accurate, traceable and repeatable measurements
In busy ports, commercial operations cannot stop. Commissioning surveys must therefore be carefully planned and professionally executed.
The Solution: Structured CP Commissioning Methodology
- Allow the System to Polarise
Following installation, sacrificial anode CP systems should be left to polarise the structure for several months.
This allows:
- Equilibrium of CP potentials
- Formation of calcareous deposits on new steel (where applicable)
- Stabilisation of protective current distribution
This is particularly important for new-build systems, where no prior calcareous deposits exist.
- Accurate Dropcell CP Potential Measurements
Access along the full length of the quay wall is required.
Using a properly calibrated Silver/Silver Chloride/Seawater (Ag/AgCl/seawater) dropcell, CP potential measurements should be recorded:
- Adjacent to the sheet piles (≤ 0.5 m from the face)
- At approximately +0.0 m Chart Datum (where possible)
- At regular chainage intervals (typically every 5 m)
Consistency is key to obtaining reliable data.
- Location Planning & Trend Benchmarking
A detailed location plan should be compiled showing all dropcell measurement points.
This allows:
- Repeatable measurements in future surveys
- Long-term performance trending
- Identification of any localised under-protection
- Identification of any interference or CP drain problems
Photographic records should also be maintained to document asset condition and highlight anomalies at the time of inspection.
- Data Review & Acceptance Criteria
Recorded CP potentials must be assessed against the design acceptance criteria.
Commissioning confirms that:
- Adequate polarisation levels have been achieved
- Protection is evenly distributed
- No areas of under-protection exist
- Interference or CP drain areas have been identified
Electrical continuity between sheet piles must also be verified to ensure uniform current spread across the structure.
Why CP Commissioning Matters for Asset Integrity
CP commissioning provides confidence that the installed system is performing as intended or at least trending correctly during early stages.
Regular CP surveys throughout the system’s lifetime then ensure:
- Continued compliance with design criteria
- Early detection of performance changes
- Planned replacement before end of design life
Depending on client requirements, dropcell surveys are typically carried out annually or biennially.
Routine CP monitoring today prevents major structural repairs tomorrow.
Professional CP Commissioning & Monitoring
At Subsea Corrosion Ltd, we measure, verify, and confirm that installed CP systems provide the correct level of protection, delivering clear, defensible data and practical engineering recommendations.
Whether commissioning a new sacrificial anode system or auditing an existing installation, our structured approach ensures your steel infrastructure remains protected for the long term.
Need a Dropcell Survey or CP Consultation?
Protect your harbour and marine assets with professional, data-driven CP monitoring.
sales@subseacorrosion.com
www.subseacorrosion.com
Commission correctly. Monitor consistently. Protect long term.
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