Cathodic Protection for Transmission Lines
The SFPUC owns and operates hundreds of miles of steel pipelines that bring drinking water to 2.7 million customers in four Bay Area counties. To protect our transmission pipelines from corrosion, we utilize a common method called cathodic protection. Corrosion can weaken the steel pipelines, resulting in leakage and eventual pipeline failure.
What is cathodic protection?
Metal such as steel that has been extracted from its primary ore has a natural tendency to revert to its original state – via a process called corrosion. Soils create an environment that is conducive to the corrosion process and as a result steel pipelines will corrode when placed into soils unless steps are taken to mitigate this destructive process. Cathodic protection prevents corrosion from happening to a pipeline by applying a protective current from an external DC power source, also known as a rectifier, through a metal rod called an “anode” drilled deep underground. The protective current then passes from the anode to the pipeline. The resulting direct electrical current flow then causes the pipeline to become a “cathode”, thus mitigating the corrosion process. A cathodic protection system is a cost-effective way to protect buried steel pipelines from the corrosive water and soils around it.
Where will the project take place?
There are eleven individual sites in Fremont, Newark, Redwood City, Mountain View, Los Altos and Stanford where we will install new cathodic protection equipment. SFPUC engineers selected these in order to protect the pipelines at key points along their right of way.
East Bay Locations: Sites 1-5
Peninsula Locations: Sites 6-11