Which type of cathodic protection system is typically required for existing underground tank installations?

In the context of underground storage tanks, the impressed current system is often required for existing installations as it provides a more reliable and robust form of cathodic protection. Unlike sacrificial anode systems or galvanic systems, which rely on the natural electrochemical potential of metals to protect tanks by corroding the anode instead of the tank, impressed current systems utilize an external power source to provide a continuous flow of current. This allows for greater control and can address the varying levels of corrosion rates that can occur due to soil conditions, moisture content, and other environmental factors.

Additionally, impressed current systems are capable of covering larger areas and can protect multiple tanks from corrosion simultaneously, making them particularly effective for larger facilities or installations with multiple tanks. This reliability and wider coverage make it a preferred choice for existing tank installations, ensuring compliance with regulatory standards for corrosion prevention and tank integrity.

This understanding highlights the importance of selecting the right type of cathodic protection system based on the specific conditions of the tank installation and the effectiveness required to prevent corrosion.