One of the biggest challenges facing our aging infrastructure today is materials loss and deterioration by the electrochemical reactions that cause corrosion. Many government studies indicate that in the US alone, costs due to corrosion loss is more than $400 billion annually.
Most of the corrosion loss on the infrastructure can be prevented by science and technology that is available to us today. Cathodic protection is a proven science that is utilized to help extend the useful life of infrastructure, and help to prevent corrosion related failures of pipes, storage tanks and other vessels carrying liquids, gases and hazardous materials. Preventing corrosion related failures keeps hazardous materials from polluting the environment. Corroded and deteriorated infrastructure also creates a public safety risk which we must address. Also corroded (rusty) structures are an eye sore?
When metallic structures are placed in soil or water, there are natural electrochemical reactions that take place. These reactions with the environment create natural anodic and cathodic areas on the surface of the structure. The anodic (positively charged) areas corrode, lose current and lose metal while the cathodic (negatively charged) areas gain current and don’tcorrode. Scientists determined that if the entire structure can become cathodic and receive current, corrosion can be mitigated.
Cathodic protection works by inducing a DC current onto the corroding structure. As the pipe is receiving the DC current, it becomes a cathode, hence cathodic and it has been proven that this process prevents metal corrosion loss. The current source comes from placing higher charged metals called anodes in the same electrolyte environments as the structure to be protected and connecting the anode to the structure. The anode can be a galvanic type, using zinc, magnesium or aluminum alloys. Also the anode can be impressed current type, which uses an external power source, using a rectifier, which forces the current through the anode. Either way, the anodes create a positive DC current and the current leaves the anode surface and is picked up by the corroding structure (the cathode) and then the current flows through the structure and back to the connecting wire and then to the anode again. The entire system can be compared to a DC battery circuit. There is the anode, the cathode, the electrolyte and a metallic current path. All four of these items are needed for corrosion to occur and by coincidence, all four are needed for cathodic protection to work.
If the infrastructure does not have cathodic protection and is allowed to corrode or deteriorate, the replacement costs are very high. The costs of a properly designed and maintained corrosion control (cathodic protection) system are exponentially less than the costs of replacement.
Using broad-based industry experience, cathodic protection specialists and professionals offer their clients innovative, cost effective and long-term solutions for preserving their assets through corrosion control. They accomplish this through commitment to rigorous science and design procedures, advanced research, and proper application of a broad range of products and services aimed at preserving piping, equipment and infrastructure in diverse industries and environments throughout the world. These services allow commercial and government institutions to stop the corrosion of metallic structures, which, in turn, prevents or substantially delays the vastly higher expenditures required to replace deteriorated and unsafe structures.
Cathodic Protection (CP) is a proven science that has been (and still is) being utilized worldwide for the purpose of control and mitigation of corrosion activity on both buried and submerged structures. Cathodic protection can extend the useful life of infrastructure for many years and save a lot of money. It is a cost effective way to extend the life of a structure and to ensure integrity throughout its operating life.
One organization that is committed to corrosion control is The National Association of Corrosion Engineers (NACE) International. NACE has a corrosion control and cathodic protection training and certification process. Technicians and engineers who are in the corrosion control industry can become NACE certified in the field of cathodic protection.
Cathodic protection professionals serve the following industries:
* Power and Energy
* Independent and General Contractors
* Architectural and Engineering Firms
* Water and Wastewater Municipalities
* Oil and Gas Industries
* The Federal Government
* Alternative/Clean Energy
* Lite Rail Systems (DC) and High Speed Trains
* Mobile Home Parks
* Service Stations
* All other Infrastructure and Industries
* Above and Below Grade Storage Tanks (Water, Chemical, Petroleum, etc.)
Some of the structures that can be considered for cathodic protection may include but are not limited to the following:
* Above Grade & Buried Pipelines of All Types (DIP, CCP, PCCP, Carbon Steel, PVC, etc.). Chemical, Petroleum and Water Pipes
* Marine Structures such as Mooring Dolphins, Sea Walls, Pipe Piles, Offshore Platforms and more
* Reinforced Concrete Structures
* Submerged (Internal) and Soil-Side Surfaces for Storage Tanks
* Lite Rail Systems and High Speed Trains
* Well Casings
* Intake Structures, Water Boxes and Other Structures at Power Plants
* Clarifiers, Trash Racks, Sludge Thickening Tanks and Other Structures at Water and Wastewater Treatment Plants
* Submerged Pumps and Piping at Pump Stations
* Electrical Grounding Systems at Satellite Towers and Other Locations
* Buried cables
* All Other Related Metallic and Reinforced Concrete Structures
Cathodic protection cannot be seen be the naked eye, but decades of research have proven its ability to stop corrosion. When utilized and maintained properly, along with other corrosion control methods such as materials selection and protective coatings, cathodic protection can extend the service life of infrastructure for decades or even longer.
By David Aimal Kashifi. The author is the founder of CorrosionCP.com and a cathodic protection engineer with over 15 years of experience in the field of corrosion control engineering.
Visit the Author's website: http://corrosioncp.com