Corrosion can occur in basically any type of underground storage tank. Fortunately, cathodic protection can be used to curb the damage that corrosion can cause. There are several types of cathodic protection that may be used to prolong the life of these tanks. These include impressed current and sacrificial anodes, and they function in similar ways. No matter what kind of system a company chooses, these anti-fouling measures can significantly help in increasing the usable life of an underground storage tank.
These systems utilize bushings that provide electrical isolation for the tank, a dielectrical protection coating and an anode that provides the actual protection. The sacrificial anode is more active electrically than the steel in the tanks themselves. Because of this, any sort of current that may cause corrosion will go out through the anode instead of the tank itself. In effect, it is sacrificed in order to make sure that corrosive effects on the storage tank are minimized.
Rectifiers are utilized in impressed current systems – available at Cathodicme.com to create direct current from alternating current. This electricity is then sent to metallic bar anodes that are buried in the ground near the tank using insulated wiring and then travels back to the rectifiers. This system works because the electricity flowing to the underground tank is able to negate the current going towards the tank that is generally responsible for creating corrosion.
Installation and Maintenance
Government rules mandate that these systems must be installed by individuals who are experts in corrosion control. Cathodic protection systems are required to be inspected half a year after they are put in place and every three years after they are used in continuous operation. If any repairs need to be made, the system must be inspected again to ensure that everything is functioning properly.
Impressed cathodic protection systems also need to be tested every two months to ensure that everything is working properly. It is best for companies to keep the results of the last few tests on hand in order to prove that everything is functioning properly.
Coatings used in cathodic protection must meet industry standards and regulations. When planning to install one of these systems, it is best to keep in mind that asphalt cannot be used as a coating.