Cathodic Protection

Wanted: Technical Articles for MP

To successfully communicate the wide variety of corrosion-related issues affecting corrosion professionals today, MP is actively encouraging corrosion control professionals worldwide to submit technical articles to share their corrosion-related experiences with over 36,000 NACE International members around the globe.

Cathodic Protection for Water Mains in a High-Consequence Transit Corridor

To protect pipelines in a transit corridor where they crossed underneath the light-rail tracks, construction of the line included retrofitting the pipelines with a precast concrete box culvert casing and installing an impressed current cathodic protection (ICCP) system.

Designing an ICCP System for the Hull of an Arctic Ice-Breaking Vessel

For many decades the maritime industry has depended on icebreaker ships to forge a path through ice-covered waters so other ships can safely navigate the trade routes in the polar regions of the world. The effects of breaking ice can be extremely destructive to the steel hull of an ice-breaking vessel. Ice abrasion can damage the external hull’s protective coating, which leads to exposure of bare steel and rapid corrosion. To protect the hulls of these ships from corrosion, a combination of protective coatings and impressed current cathodic protection (ICCP) is often used.

Longevity of a Graphitized Cast Iron Water Main

Graphitization is a corrosion phenomenon associated with grey cast iron. This material consists essentially of flakes of graphite in an iron matrix. The iron constituent corrodes out because of the same multitude of corrosion reactions that affect ferrous metals, leaving behind the graphite and some corrosion products.

Using Impressed Current Cathodic Protection in Urban Areas

There are times when it is necessary to use impressed current cathodic protection (ICCP) in urban areas, in spite of concerns about extensive interference. This article describes three ICCP systems that can be used safely in urban environments. They are distributed anode (parallel) groundbeds, deep anode groundbeds, and low-output surface groundbeds.

I Told You So

Cathodic protection expert John Fitzgerald uses an experience early in his career to illustrate the consequences of not heeding the advice of corrosion professionals when designing and implementing corrosion control systems—many times because of reluctance to bear the expense. Cutting corners to save money up front can lead to unexpected failures and expensive repair and replacement in the future.

Check Solar Weather Before Performing Pipeline CP Evaluation

After experiencing severe telluric current activity on a pipeline, the author researched the subject. The causes and effects of telluric currents are explained and precautions for obtaining data on forecast telluric activity are given.

Odd Occurrences During Cathodic Protection Troubleshooting

“Stop, Look, and Listen.” These words from railroad crossing signs are good ones to keep in mind when troubleshooting cathodic protection (CP). Some trouble shooting efforts are pretty straightforward, involving depleted anodes, broken wires, burned out rectifier stacks, and the like. But there are occasions when nothing seems to make sense, and then it’s time to “stop, look, and listen” and figure it out. Here are a few experiences from nearly 45 years of CP work.

The Strange Case of the Intermittent Condition

Being a cathodic protection corrosionist is a lot like being a detective. It is necessary to examine all the evidence when solving a mystery. Sometimes it is necessary to establish a stakeout. That’s what was done to find the source of intermittent shorts in this incident. Careful use of instrumentation, data analysis, and observation solved the problem.

Wireless Remote Monitoring of Cathodic Protection Systems

Wireless monitoring technologies provide the ability to acquire impressed current cathodic protection (ICCP) system performance data from remote locations using modem-equipped personal computers. The technology can monitor the remote ICCP system’s amperage, “instant-on” and “instant-off” potentials in a central location, and provide personnel with immediate warnings of system problems. Case studies are presented for one Air Force and three Army installations, each with a different approach for the monitoring.

MMO-Coated Titanium Anodes for Cathodic Protection—Part 2

Mixed metal oxide (MMO) anodes find extensive use in impressed current cathodic protection installations. Part 1 of this article covered the electrochemistry, manufacture, and operation of these anodes. Part 2 presents three case histories showing application of MMO anodes.

Real-Time Monitoring Affects Cathodic Protection

The need for real-time data is affecting the ability to provide cathodic protection (CP) to pipelines. The connection of electronic equipment required for remote pressure monitoring, metering information, valve operators, and other functions creates a direct short from the CP on the pipeline to the electric power company alternating current grounding system. In essence, the CP system now must protect not only the pipeline, but also a sizeable bare copper grounding grid. This problem creates pipe-to-soil potentials that may not meet the desired criterion. This article covers the use of decoupling devices to remedy this problem.

Cathodic Protection of Pipe Encapsulated in Polyethylene Film

Case histories are presented where polyethylene encasement and cathodic protection have been used together to effectively control external corrosion of ductile iron pipelines in corrosive soils. The four case histories evaluated include impressed current and galvanic anode protection.

Interference Problems and Nonuniform Potentials in Cathodic Protection of a Complex Installation

After being in operation for some time, cathodic protection (CP) systems at compressor stations, refineries, and other industrial plants can experience problems. For example, the CP potential distribution can change for various reasons, because of isolating flange failures, alterations in pipeline systems, grounding systems, or reinforced concrete foundations. Some areas become underprotected and others overprotected. The extent of CP current required may exceed the capacity of rectifiers, and may also increase interference on foreign pipelines. This article describes the results of corrective measures for these problems.

Designing Cathodic Protection for Power Plant Applications

Designing cathodic protection (CP) systems for buried piping in power plants and other similar industrial facilities offers several unique challenges. This article discusses these challenges and provides case histories to illustrate the impact they have on CP system design and operation.