Choosing a cathodic protection company is a long-term decision. A CP system is expected to protect a buried or immersed asset for decades, and the quality of the design, the materials and the commissioning determines whether it actually does. A system that is under-designed, poorly installed or never properly validated can leave an operator believing an asset is protected when it is not.
This guide sets out eight practical checks for procurement teams, asset owners and integrity engineers evaluating cathodic protection services. Each one is a question you can put directly to a prospective supplier, with an explanation of what a good answer looks like.
1. Check the certifications, and check the level and the sector
Cathodic protection competence is governed by ISO 15257, which defines five levels of competence for CP personnel covering survey, design, installation, testing and maintenance. Certification is granted per application sector, so a certificate is only meaningful in context.
The two recognised schemes are the Institute of Corrosion (ICorr) scheme and the AMPP scheme (formerly NACE). Under ICorr, Level 4 is the Cathodic Protection Specialist grade. Under AMPP, the equivalent progression runs CP1 Tester, CP2 Technician, CP3 Technologist and CP4 Specialist.
What to ask
- Who specifically will design my system, and what level are they certified to?
- Is that certification in the correct application sector for my asset (buried and immersed structures, marine, reinforced concrete or internal surfaces)?
- Are the field technicians certified, or only the office-based engineers?
A supplier should be able to answer this without hesitation and name the individuals. Be wary of a general claim that a company is ‘certified’ with no level, no sector and no named personnel behind it.
2. Ask which standards the design will be built to
A cathodic protection design can only be approved if it is developed in accordance with a recognised standard. The standard defines the protection criterion, which is the measurable threshold that proves the system is working. Without one, there is no objective basis for accepting the system at handover or auditing it later.
The standards that should appear in a scope of work include:
- ISO 15589-1: cathodic protection of onshore pipeline transportation systems.
- ISO 15589-2: cathodic protection of offshore pipelines.
- EN 12954: buried or immersed metallic structures, general principles and application.
- AMPP SP0169 (formerly NACE SP0169): control of external corrosion on buried or submerged metallic piping.
- BS EN 50162: protection against corrosion by stray current from direct current systems.
- DNV-RP-B401 and ISO 24656: offshore and offshore wind structures.
Ask the supplier to state, in the proposal, which standard governs the design and what protection criterion they are designing to. If the answer is vague, the acceptance test at the end of the project will be vague too.
3. Find out whether the design is done in-house
Many suppliers sell CP materials and subcontract the engineering. That is not automatically a problem, but it changes who is accountable when a system underperforms and it usually slows down any change during the project.
A supplier with genuine in-house design capability should be able to describe their own calculation and modelling process: current requirement calculations, anode sizing and output, groundbed design, circuit resistance and cable voltage drop calculations, layout and installation drawings, and the commissioning procedure. Corrpro Europe carries out this work in the UK using in-house cathodic protection (CP) engineers, proprietary design software, and CAD drafting capabilities. As part of the design package, we also provide detailed bills of quantities.
What to ask
- Is the design produced by your own engineers, or subcontracted?
- Can I see a redacted sample design package?
- Who carries the design liability?
4. Establish whether they manufacture or simply resell
There is a meaningful difference between a company that manufactures CP equipment and one that buys it in. A manufacturer controls quality, traceability and, critically, lead times. They can also make non-standard items when a project needs them, rather than forcing the design to fit whatever is available in a catalogue.
Corrpro Europe manufactures at its Stockton-on-Tees facility in the UK, with a foundry and assembly operation producing galvanic and impressed current anodes in zinc, aluminium, magnesium, MMO and silicon iron, alongside transformer rectifiers, junction boxes, test stations and reference electrodes. The quality management system is registered to ISO 9001:2015, with the registration covering design, engineering, manufacture, servicing and surveying of cathodic protection equipment.
What to ask
- Do you manufacture the anodes and power supplies, or buy them in?
- Where are they made, and can I visit?
- Is your quality system certified, and what does the scope of that certificate actually cover?
The scope point matters. An ISO 9001 certificate that covers only ‘distribution’ is a very different thing from one covering design and manufacture.
5. Ask about lead times and stock, and ask for specifics
Lead time is where CP projects most often slip. Anodes, cables and transformer rectifiers are not commodity items, and a shutdown window or a pipeline tie-in will not wait for a twelve-week delivery. Suppliers holding real stock and manufacturing locally can respond in days rather than months.
What to ask
- What is your typical lead time for the specific items in my bill of quantities?
- What do you hold in stock, as opposed to what you can order?
- What happens if my programme moves forward by four weeks?
Ask for a lead time against your actual materials list, not a general statement. A supplier confident in their stock position will give you item-level answers.
6. Check they cover the full project lifecycle
Corrosion control is not a single transaction. A CP system needs surveying before design, commissioning after installation, and monitoring for as long as the asset is in service. Where those stages are split across several suppliers, responsibility for the outcome tends to dissolve at each handover.
A full-lifecycle supplier should cover feasibility and site assessment, design and specification, materials supply, installation or installation supervision, commissioning and validation testing, and ongoing monitoring and maintenance. Ask how each stage is resourced and whether the same organisation is accountable throughout.
7. Confirm they can assess and mitigate AC and DC interference
This check is increasingly important and is frequently missed. Buried pipelines now routinely share corridors with high-voltage power infrastructure, and induced or conductive interference can create a safety risk to personnel, damage coatings and cause AC corrosion at coating defects even where the CP potential criterion appears to be met.
Interference assessment is a specialist discipline. It requires field investigation, high-resolution data logging across varying operational states, and computer modelling for complex pipeline and energy corridor scenarios. Many CP suppliers do not have this capability at all.
What to ask
- Can you carry out an interference study, or do you subcontract it?
- Do you model induced voltages across the full route before designing mitigation?
- Can you supply and install the AC and DC mitigation, including decoupling and earthing systems?
Corrpro Europe’s approach to this is set out in more detail on our AC interference in pipelines article.
8. Look at what the reporting and long-term support actually contain
A survey report full of raw data is not an engineering deliverable. What an asset owner needs is an interpretation: what the data means, whether the asset is protected, where it is not, and what to do about it. Ask to see a sample report before you appoint anyone, and check whether it ends with numbers or with recommendations.
Long-term support matters just as much. Ask whether the supplier can maintain the system they install, whether they support legacy and third-party equipment, and whether remote monitoring is available. A supplier that is the original equipment manufacturer for a system can support it with genuine parts for decades, which is a significant advantage on assets with long design lives.
Quick checklist: choosing a cathodic protection company
Before appointing a cathodic protection company, confirm the following:
- Certification: named personnel certified under ICorr or AMPP to ISO 15257, at the right level and in the right application sector.
- Standards: the design is written against ISO 15589, EN 12954, AMPP SP0169 or the relevant sector standard, with a stated protection criterion.
- Design: engineering carried out in-house, with a sample design package available.
- Manufacturing: equipment made, not just resold, under a quality system whose scope covers design and manufacture.
- Lead times: item-level lead times against your bill of quantities, backed by real stock.
- Lifecycle: survey, design, supply, install, commission and monitor under one accountable organisation.
- Interference: in-house AC and DC interference assessment, modelling and mitigation.
- Reporting: engineering analysis and recommendations, not raw data, plus long-term and legacy support.
How Corrpro Europe measures against this list
Corrpro Europe has provided cathodic protection design, materials and field services for over 50 years, working across the UK, Europe, the Middle East and Asia. Our engineers and field technicians are ICorr and AMPP certified. We design in-house to ISO, EN and AMPP standards, manufacture anodes, Hockway transformer rectifiers and junction boxes at our own UK facility in Stockton-on-Tees, and support projects from initial survey through to commissioning, remote monitoring and long-term maintenance. We also carry out AC and DC interference assessment, including computer modelling for complex energy corridors, and act as the original equipment manufacturer for legacy marine CP and antifouling systems.
For more detail on our capability and approach, see our Why Choose Corrpro Europe page.
For the full scope of design, survey, commissioning and monitoring services, see our Cathodic Protection Engineering Services page.
Frequently asked questions
What qualifications should a cathodic protection company have?
Look for personnel certified under the ICorr or AMPP schemes against ISO 15257, which defines five competence levels for CP personnel. ICorr Level 4 is the Cathodic Protection Specialist grade, and AMPP CP4 is the equivalent specialist level. Certification is sector-specific, so confirm it covers your asset type. The company itself should also hold a quality certification such as ISO 9001, with a scope that covers design and manufacture rather than distribution alone.
Is it better to use a cathodic protection company that manufactures its own equipment?
Generally yes. A manufacturer controls quality, traceability and lead times, and can produce non-standard items when a design requires them. A reseller is dependent on third-party stock and lead times, and cannot usually adapt equipment to fit a design constraint.
What standards should a cathodic protection design comply with?
For onshore pipelines, ISO 15589-1. For offshore pipelines, ISO 15589-2. For buried and immersed structures generally, EN 12954. AMPP SP0169 covers buried or submerged piping, and BS EN 50162 covers stray current corrosion. Offshore structures and offshore wind are covered by DNV-RP-B401 and ISO 24656. The proposal should name the governing standard and the protection criterion.
How much does a cathodic protection system cost?
Cost depends on the structure, the current demand, the electrolyte and the design life, so any figure quoted without a survey is guesswork. What you can compare between suppliers is the basis of the design: the standard applied, the design life, the calculation and what is included beyond supply, such as commissioning, documentation and monitoring. A low price that excludes commissioning and validation is not a like-for-like comparison.
Do I need a cathodic protection survey before commissioning a system?
Yes. Design inputs such as soil resistivity, existing structure potentials, electrical continuity and interference exposure can only be established on site. A design produced without survey data is based on assumptions, and any supplier willing to design without them is worth questioning.
