Article

Early detection, prevention

My sister-in-law is a four-time cancer survivor, including breast cancer.

She wrote a book called “God in the Picture,” designed to share her faith and offer hope to women who have cancer and are going through treatment. She promotes regular mammograms as the best way to detect and prevent growth of breast cancer.

There has been a firestorm in the medical community over new guidelines, issued by the U.S. Preventive Services Task Force, recommending women begin to receive regular mammograms at age 50, instead of age 40. The American Cancer Society continues to support the position that such screening should begin at age 40 for all women.

What does this have to do with cathodic protection for underground storage tanks? It’s about early detection, leak prevention and safety.

With a national increase in the installation of aesthetically popular underground propane storage tanks for domestic use comes the greater need to educate and train marketers and customers on the important benefits of corrosion prevention.

Amazingly, one equipment wholesaler said, “We get inquiries from marketers because a customer wants an underground tank and neither understands the importance and function of a cathodic protection system. Both parties don’t want the cost, perceived headaches and responsibility of checking system function.”

The problem
Corrosion of steel tanks or copper and steel piping is an electrical and chemical deterioration of the metal. All soil contains water and dissolved minerals responsible for damaging an underground tank. Specifically, scratches, nicks or rocks can expose bare metal to greater acceleration of damage.

While it can be argued that certain soil is more corrosive than others, the prospect of other chemicals such as lawn fertilizers can accelerate corrosion and occurs throughout the country.

The solution
Cathodic protection is a system used to protect the tank from corrosion: attaching an anode to the tank and making it cathode. The anode absorbs the corrosion and protects the cathode.

LP Gas featured an article on corrosion defense in June 2008. It highlighted the new Propane Education & Research Council instructional program intended to educate and inform marketers on key points of cathodic protection on underground tanks. The program was designed to help marketers understand why they need training to install, activate and test systems correctly. It is a great educational tool and clearly recommended for marketers who install, service or deliver to underground tank systems.

Protection monitoring
Protection monitoring is a critical part of measuring effective function and is accomplished by measuring the voltage difference between the steel tank and a copper-copper sulfate electrode placed near the tank. Checking for proper anode function once a year is an easily trainable duty to be performed by the driver while making a delivery. In fact, most manufacturers recommend checking once a year.

The installation of cathodic protection on an existing underground tank will not repair the existing corrosion damage, but it will protect the surface from additional damage. It is possible that some tanks may have to be excavated to visually inspect the damage.

The Department of Transportation requires an annual check of commercial tanks, and NFPA 58 is weighing the merits of an annual check to confirm the cathodic protection system is working properly. The recommendation has widespread support from marketers, manufacturers and safety folks alike.

If you sell, install, service or deliver to domestic underground tank systems, I recommend you adhere to manufacturers’ recommendations regarding installation and annual testing of cathodic protection systems.

Catching a problem early can be lifesaving for breast cancer patients. The same can be said of cathodic protection detection before corrosion deteriorates the metal tank. Every corrosion problem detected and corrected could be an underground leak accident prevented. Those are results we can live with.