Back to basics – the benefits of cathodic protection
- Cathodic protection is an essential component of pipeline integrity programs, but its perceived value to operators varies widely across the industry.
- Cathodic protection is most effective as a second line of defense to pipeline coatings.
- Our personal experience, academic findings, and the industry’s collective wisdom bear witness to the role of CP in maintaining pipeline integrity.
- Technological improvements such as remote monitoring and data management can reduce the workload of managing large or remote cathodic protection systems.
The response to cathodic protection (CP) varies from company to company and manager to manager. Some understand its importance and give it the time and funding it requires to be effective, but others don’t see much value in it at all.
Pipeline operators install and maintain CP on their lines as required by federal and/or state regulations. But sometimes, managers express a natural dislike for expending resources on something with such an intangible return. One terminal manager illustrated what he thought of cathodic protection by flushing a toilet – to him, it was just money down the drain.
But cathodic protection is about far more than meeting regulations. It’s a scientifically established and well-proven way to prevent and mitigate corrosion and protect and maintain the integrity of underground pipelines. However, since the day-to-day evidence of CP’s effectiveness is that nothing happens, it’s easy to question whether the CP is really preventing corrosion, or whether corrosion just isn’t much of a threat to the line in the first place.
To an observer, CP can seem like an expensive military force that’s not fighting any battles. It’s difficult to say exactly what your enemies would do without the deterrent, and it can be tempting to divert resources to other priorities, especially when the deterrent has resulted in a long period of peace. So how do you put a value on peace, on “nothing happened? “
One way to do it is through estimating what the cost would be if “something” did happen – in this case, a corrosion-related leak or catastrophic failure. Such failures carry long term costs that far outweigh the resources devoted to a CP program.
Why protecting your line matters
Depending on the type of product and the location of the failure, a leak resulting from corrosion can result in injuries and/or loss of life, risks to public safety, and harm to the environment, not to mention the lost product and lost pumping time during clean up and repair. Beyond the immediate impact of a leak, spills can lead to regulatory sanction, increased scrutiny by regulators, and damage to community relations.
Also, due to the challenges involved in building new or replacement pipelines, there’s an increasing need to maximize the longevity of the ones we have. The combined cost and effort of permitting and regulatory approval along with design, construction, and landowner negotiations are always significant and sometimes prohibitive.
Clear evidence that cathodic protection works
There is ample reason for pipeline operators to include CP as a key part of their integrity management programs, with coatings acting as the primary protection against external corrosion, and CP adding supplemental protection.
For some physical evidence of the effectiveness of CP in pipeline integrity, consider the story behind the photograph below.
A client recently dug up a section of pipe originally installed in 1939 for inspection. The excavation exposed a tie-in of the original 1939 pipe to a 1990’s vintage pipe replacement. The 1990’s vintage pipe on the left was installed with fusion bonded epoxy (FBE) coating and shows no evidence of external corrosion in its near 30-year life.
The 1939 pipe on the right was installed bare, and before cathodic protection technology was fully developed and commonly used. The 1939 pipe shows a highly pitted condition caused by external corrosion.
Records show that the 1939 pipe experienced numerous corrosion leaks and pipe replacement repairs until the application of CP in 1972. That CP system was designed and installed by D. Tongue and Associates, the predecessor of the present-day HT Engineering. After the installation of CP, the corrosion was arrested and the line is still in service today without any leaks.
This case provides compelling evidence that coating and cathodic protection do make a positive difference, and can help preserve your assets for many decades.
Beyond this example, there’s widespread recognition by entities such as AMMP (formerly the National Association of Corrosion Engineers) and other pipeline industry associations, plus academic institutions, that CP is a critical and integral part of corrosion prevention and asset integrity for pipelines.
Technology is improving
Technological developments are also making it easier to design, maintain, and manage effective CP systems:
- Providing AC power for CP installations in some remote locations or marshland can be difficult. The use of thermal electric generators or properly designed solar powered installations are options worth consideration.
- Meeting regulatory requirements to verify proper operation of CP systems used to mean significant travel time and visits to remote locations for a technician to physically inspect the required portions of a large CP system. Improvements in the reliability and accuracy of remote monitoring systems can relieve an organization of the time commitment required to perform these inspections in person, allow for data collection to occur automatically, and provide for quicker evaluation and easier recordkeeping.
- Utilizing an electronic database specifically designed for CP systems allows for quicker and more complete evaluation of data from full field inspections. This helps to identify trends that may indicate the need for system adjustments or maintenance before a failure in the system occurs.
- Advances in information technology allow for secure storage of massive amounts of electronic data that can be available from practically anywhere. The ability to quickly and efficiently produce the required data for review during regulatory audits is invaluable. For more on this, please see my colleague Jason Larman’s article on record-keeping for PHMSA audit purposes.
The role of external expertise
Pipeline specialty firms such as HT Engineering can help you prevent and mitigate corrosion by designing CP systems, preparing coating specifications, and evaluating existing systems to ensure they are effective and audit-ready. Consider scheduling a “pre-audit” with our team to ensure your records are available, complete, and that personnel involved in audits are knowledgeable and ready to discuss and answer question about the pipeline system with state or federal inspectors.