Cathodic Protection Training Course

Module 2



Explanation of the reasons behind current trends in C.P. Technology.


  • Cathodic protection theory dictates that the metal must be reduced to below its corrosion potential IN RELATION TO A STANDARD REFERENCE POTENTIAL.

  • Top corrosion scientists regard the copper/copper sulphate electrode as a 'reference' electrode, capable of rendering a potential to which all C.P. work can be related.

  • Standard reference electrodes have a recognised and known potential which can be used as an electrical datum point against which to measure other potentials.

  • Complete cathodic protection is totally achievable but the problem is to measure the effectiveness of cathodic protection when applied in the field.

    The illustration below shows the traditional method of making the voltage measurement that has been the basis of all cathodic protection design and monitoring since the 1950's



    Typical test posts at a road crossing in the UK



    As a general guide the value of -.850v in relation to a copper/copper-sulphate electrode was chosen as a criterion for the achievement of cathodic protection. It was felt that this was substantiated by the Pourbaix diagrams and since then all attempts at monitoring the effectiveness of cathodic protection been based on this value and the use of this electrode.

    Cathodic protection has been very cost effective and successful and consequently has become required as a maintenace technique for pipelines world wide.

    Being so cost effective has resulted in it being very lucrative for those offering it as a service.

    It is very simple to install and commission and the equipment and parts are readily available from many sources.



    Almost anyone with a rudimentary understanding can design a system that will reduce corrosion by about 90% and so we have a situation now that there are many 'cathodic protection experts' in positions of authority, world wide who cannot explain why pipelines fail due to corrosion that should be prevented.



    Our instruments are capable of measuring VOLTAGES which are the differences between two potentials. Cathodic protection salesmen refer to measurements as POTENTIALS...... they are NOT. They are potential differences..... VOLTAGES.

    The potential at either pole of the meter can be regarded as zero and the other pole will be either charged higher or lower. The meter will show positive or negative values according to the polarity of the connecting conductors but the value displayed will be a voltage. Even when displayed on a 'scope' type of instrument.

    It is this misunderstanding that has caused the delay in the fruition of cathodic protection as a science and engineering technology.
    Top scientists are anxious to sustain their present concept as this affects their very livelihood.

    Their 'consultancy advice' has been taken by organisations such as NACE and various pipeline standards authorities world wide.

    It is very difficult for them to explain that the standards and criterion that they recommend cannot be applied in the field of pipeline cathodic protection.

    They have sold this criterion as an axiom on which they can base scientific calculations for the purposes of design of cathodic protection systems.



    The effect of 'business competition' on cathodic protection.


    In a world where money rules, it should be recognised that all those who have the job of preventing corrosion to pipelines have the priority objective to sustain their position and to earn as much personal money as they can.

    The pursuit of personal money has overridden the desire to stop corrosion and this has been a greater impact than any other cause on the useful life of pipelines, world wide.

    This is the most important fact in each corrosion engineers life.

    There are two questions that are regularly directed at CPN.

    "If CPN technolgy is so good then why is it not adopted world wide?"

    The answer is that the market place economy makes it impossible to implicate changes that do not have financial benefit to those who hold the money. Considerable investment had already been made into

    The other re-occuring question is 'Where is CPN technology installed so that we can see it's success?'

    The answer is nowhere! The question is simply an attempt to gather information without paying for it. If the pipeline industry could see a working example of a new technology they would simply coppy it. The most recent people to ask this question of the CPN were the Iranians.

    The energy industry is multi-national and the pipeline industry has a pool of experts who work wherever they can get paid. When any technology is successful it will be copied and in the 'competitive market' work will be given to the company submitting the lowest tender.
    A presentation of CPN technology was given to the Iranians who are now looking for 'another source' as they do not want to pay Cathodic Protection Network International Ltd. This ignors the fact that their pipelines are corroding because they are using technology from those 'other sources' and it simply does not work.

    I can be seen that the commercial situation throughout the world has resulted in the scientific establishment controlling the only advances in technology and resisting changes that will damage their established work.

    This is not greed, selfishness or meglomania but a natural result of money being the basis of society. Everyone needs money to survive and the work ethic dictates that those who do not work are not even deserving of survival. 'Work' has come to mean 'employed' and that infers that each individual must perform some defined task. Those that are defining the task are performing work that gives them power and money. In the case of cathodic protection the top line definition is the work of scientists.

    It was a proposal by Sir Humphry Davy that resulted in the definition of the work to be done to stop corrosion to the copper cladding of wooden war ships. This successful application of the scientific principles resulted in the proposal that this science could be applied to steel pipelines that were corroding in a very short time.

    This type of cathodic protection was defined by scientists and applied by engineers very successfully resulting in those scientists and engineers being employed to stop corrosion on other pipelines.

    Other scientists studying corrosion found that coatings separated the electrolyte from the metal and stopped the reaction. Various wax and oil based coatings were reinforced with cloth and wrapped round the pipelines. These were conductive (Denso tape is an example) and the protective current from the CP systems could pass onto the pipeline metal without achieving its purpose.

    Electrically resistant bitumen coating was then used successfully but this was found to be bio-degradable and lost it's effect after a few years.

    Coal tar enamel was found to be very effective and durable especially when combined with glass fibre re-inforcement. All these steps resulted in specialised consultants becoming more significant in the fields of corrosion control, coating manufacture and application.

    Companies were formed for the manufacture of these coatings under the scientific guidance of the specialists who were paid to research better products.

    It was found that some products were so electrically resistant that they could be applied very thinly. Some had sufficient tensile strength and impact resistance that they could be applied without re-inforcement.

    Present day coatings are very efficient but none can be applied without faults because of the nature of pipeline construction.

    It is because of these coating faults that cathodic protection is required by law in most countries of the world.

    Cathodic protection is only needed at these coating faults but their location is not known.

    Industry has developed a variety of methods to detect the location of coating faults and these will be studied later in this course.

    Pipelines continue to fail through external corrosion and there is a need to monitor the effectiveness of cathodic protection. However most big pipeline operating companies only take those measures that are required by law governing the issue of their pipeline operating licences.

    There is no commercial incentive to try to enhance the effectiveness of their cathodic protection systems as the failures are covered by insurance.

    The insurance companies can easily raise their premiums and the value of oil and gas are such that the enormous profits can assimilate the cost of repair and replacement of the damaged pipelines.

    The majority of rich people world wide are best served by the present status of corrosion control and cathodic protection and that is why CPN technology has not been adopted world wide.


    The Emperors new suit


    There is a famous story of the Emperors new 'invisible' suit and the little boy who sees him nude because he has not been told of the 'magic suit'.

    This story is common to many countries and the principle must be known world wide.

    Tricksters had convinced the whole nation of this suit and the little boy wass the only person who had not received the message. His simple logic and the evidence of his eyes showed him that the suit did not exist. His exclamations to this effect werwe well received in the story but in real life the little boys comments would not be popular. He was a 'whistle blower' who upset the 'establishment'.

    The fable seems to end there, but in real life there remains the problem of the Empeorors pride and 'entrepreneurs' money.

    The purpose of this chapter is to allow the student to realise that commercial pressures have a bigger effect on pipeline corrosion than the natural effects of the corrosion reaction.




    The technology contained in this course will not please many in the cathodic protection industry as it challenges the very foundation of much of their work.

    NACE and the rest of the cathodic protection industry have based all their efforts on the fact that the copper/copper-sulphate or silver/silver-chloride electrodes renders a reference potential on which it is possible to base cathodic protection design and monitoring.

    That is the 'invisible suit' that they sold to pipeline operators who wanted a criterion so that they would know when cathodic protection was effective and had indeed stopped corrosion.

    Sir Humphrey Davy had proved that cathodic protection actually worked when applied to copper cladding on ships and pipeline operators found that leak frequencies dropped off dramatically when cathodic protection was applied to pipelines but no one could say when the application was complete and to what extent it had been achieved.

    When it was recognised that there were errors in the measurements these were, at first, blamed on inaccurate instrumentation and poor field work.

    With the availability of digital instruments and some laboratory studies it was possible to identify that there were real errors in field measurements that are not present in laboratory techniques. These errors were all described as 'the IR drop in the soil'.

    It is significant that the 'experts' did not use the simple world 'voltage'. This would have made it simple for any electrician to see the error and recognise the way the mistake had come about. It would clarify the route to a simple solution such as the Alexander Cell. However, this would not sell the 'invisible suit'. It was necessary to cloud the issue with new terminology.

    Scientists thought that they could eliminate the errors by taking the required voltage with the cathodic protection current switched off. It seemed that the error was caused by the measuring circuit alone and that by removing the current that was causing the voltage error, the measurement would be equivalent to the actual reading at the interface, as required by Pourbaix.

    The very first lagre scale attempt to utilise the 'off potential' theory was carried out by North Thames Gas in the UK.

    It was then realised that most pipelines were affected by more than one transformer rectifier and that the current had not actually been switched off but had been reduced by an unquantifiable amount.

    Attempts were then made to sychronise the switching of all the transformer rectifiers that affected each length of pipeline. This was difficult in the 1980's as the technology was not available.

    Instrument manufacturers and cathodic protection providers came out with more and more sophisticated sychronised switching systems in an attempt to achieve the required 'immediate off' potential.

    In 2001 Roger Alexander (the little boy who saw the Emperor was nude) was requested by NASA to submit a report for consideration by the American Standards Authority relating to the Immediate Off Potential Survey.

    Click here to see the paper sent to NASA


    Cathodic protection is required by law in most countries as a condition for a pipeline operating licence. However, there is no internationally agreed criterion for the achievement of complete protection.

    Pipeline operators are required to report leaks but it is very difficult to compile information about this.

    The use of the CIPS survey is an attempt to apply the Pourbaix theory based on the voltage between the metal potential and the electrolyte potential but the DCVG survey shows that the same electrode renders a different value in each location. This makes it possible to accurately identify the position of coating faults using the difference in ground potentials touched by copper/copper-sulphate electrodes but proves that the CIPS survey CANNOT determin the corrosion status of the pipeline metal.

    Faced with this problem, the cathodic protection industry has no scientific point of excellence that can answer the simplest questions levied by the most fundamental electrical and electronic engineers.


    CIPS and DCVG are being used world-wide despite the limitations of DCVG and the complete failure of CIPS to determine the corrosion status.

    Mainstream scientists still insist on trying to use the Cu/CuSO4 electrode as a reference potential and consequently the CPN is the only organisation that can offer the computerisation of pipeline cathodic protection,

    The adoption of CPN technology in Iran is currently being delayed by financial and business considerations but it is significant that this technology would save the country money that is being spent on unsuccessful methods of applying cathodic protection. Less money spent on CPN technology would stop most of the corrosion that is causing massive financial losses and ecological damage.

    This is the same situation that pertains in the rest of the world but Iran has at least had the sense to examine cathodic protection and look for better ways of applying it.

    No doubt the people of Iran will apply the same sense when looking at the financial situation surrounding their massive corrosion related losses.


    Money and esteem


    Those who are not good at making money are seen as failures and their work is not respected.

    It is similar in principle to qualifications... if a person has no qualifications, he cannot know about the subject under discussion. It then follows that a persons word is a valuable as his apparent wealth. The notion is that if a person is not rich, he/she is not intelligent or wise.
    The logic is that everyone knows that money = success and if you have no money you are a failure.

    What has this got to do with corrosion control and cathodic protection in particular?

    All of the above have directly affected the present status of corrosion control and cathodic protection. Pipelines continue to fail and are repaired or replaced at enormous expense and loss of money, energy and sometimes life.

    If one of these failures reaches the general public there is an investigation and enquiry that takes enough time for the public to lose interest. In the event of the incident becoming politically important, many lawyers and polititians make a lot of money. The first reaction of the investigators is to ascertain the cause of the failure. These investigators normally are people involved with the maintenance of safety standards and are keen to find taht the cause is not with themselves or their immediate friends and associates.

    The most convenient cause is local activity at a low social level. In the case of a developing nation this is usually found to be people trying to steal the product or clumsy behaviour of a mechanical device such as a digger or tractor.

    It is very rarely blamed on corrosion as this is preventable by people in positions of power and wealth, but if that is the conclusion of the inquiry then the consultants have a ready excuse in that they claim that there are matters beyond the control of science and that they can never guarantee total success of cathodic protection.

    The British Standards Institute Code of Practice CP1021 was withdrawn by Jim Gosden when it was proved in public that the recommendations could not be practiced. It has been replaced by a very loose document that carefully avoids any specific procedure.

    The National Association of Corrosion Engineers based in the USA (NACE) has gained world wide authority over the years as no other national or international body has come forward with a workable criterion for cathodic protection. They publish a standard for cathodic protection of pipelines that is available on the internet at a cost of $83. I am the founder and owner of CPN and cannot afford this as no businessman or entrepreneur is prepared to pay any money to me. NACE will not answer any correspondence from CPN and it is proving impossible to arrange an official meeting with UK authorities.

    It would seem that financial and commercial considerations are more important than stopping corrosion.

    CPN is not a commercial success but CPN technology has prevented and halted corrosion in every challenge that has been faced during the past 30 years.

    The Alexander Cell is still the only clear method of indicating the effectiveness of cathodic protection and yet nobody is using it for purely commercial and business reasons.

    I am at present considering giving away the home made Alexander Cells that I have in my posession so that they will prove that CPN technology really works in the field.


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