2. ONSHORE STRUCTURES

Unless protective measures are taken, buried metal tanks, piping, and other metal components of fuel storage systems corrode (rust) and eventually leak product into the environment.

Underground storage tank (UST) system components must be continuously protected against corrosion. This can be accomplished by installing non-metallic tanks such as fiberglass, by coating metal tank systems to isolate them from contact with the corrosive environment (soil), or by using a technique called cathodic protection (CP). There are two types of cathodic protection for metal tank systems: Galvanic CP and Impressed Current CP.

When properly installed and maintained, CP can prevent corrosion on the outside surfaces of steel tanks, piping, and other metallic storage system components. It is the UST operator’s job to ensure that the CP system is properly maintained and operated so that the UST system remains protected from corrosion. Owners or operators are required to maintain the CP system until an UST is removed from the ground.

Application of Cathodic Protection for onshore structures are as follows:

1. Underground pipelines.

2. Buried tank.

3. External surface of tank bottoms.

4. Tank Internal Surface