Can Copper Silver Ionization Contribute to Corrosion?

Copper-silver ionization (CSI) is a method used for disinfecting water systems, particularly in controlling Legionella and other gram-negative bacteria. The process involves releasing copper (Cu²⁺) and silver (Ag⁺) ions into the water, which act as biocides.

Copper-silver ionization is not inherently corrosive when properly managed.  However, if the system is not well-managed, the ions and the overall water chemistry can lead to plumbing issues. For that reason, anyone using CSI should have a thorough water management program that includes Legionella testing, Legionella risk assessments, and copper and silver ionic tests of the water system.

Possible Plumbing Issues Associated with Copper-Silver Ionization Systems

There are two types of plumbing issues that can be associated with copper-silver ionization if not properly managed.

Localized Corrosion (Pitting)

• Copper ions, if concentrated or unevenly distributed, can lead to pitting corrosion in copper or other metal pipes.
• If copper ion concentrations become excessive, they can deposit unevenly on metal surfaces. This imbalance can lead to the development of pits, which may eventually cause leaks or failures in the piping system.

Erosion-Corrosion

• In systems with high flow rates, the presence of copper and silver ions could possibly contribute to erosion-corrosion.
• If the velocity of water flow is high, particularly in areas with sharp bends or constrictions, the mechanical force of the water combined with the presence of metal ions could wear away the pipe surfaces, causing erosion. However, this can happen without any copper or silver in the water.

Preventing Corrosion in Copper-Silver Ionization Systems

To prevent corrosion when using copper-silver ionization, it is crucial to maintain optimal system conditions:

• Monitor ion concentrations: Regularly test and monitor copper and silver ion levels to ensure they stay within the recommended range (e.g., 0.2–0.8 mg/L for copper and 30 – 80 ppb for silver).
• Monitor Conductivity, hardness, and pH in the water and adjust as needed.
• Regular maintenance and inspections: Routine inspection of the CSI and water system for signs of corrosion and implementing timely repairs can help mitigate long-term damage.

Work with An Expert When Using Copper-Silver Ionization
While copper-silver ionization is an effective disinfection method that works in a wide temperature and pH range, improper management of the ion levels or water chemistry could lead to various forms of corrosion or other issues with piping systems. Ensuring proper monitoring of ion levels and water chemistry is key to Legionella disinfection and prevention of piping failures in the plumbing systems. It is important that you work with a Legionella control expert that has engineering expertise like Legionella Control Systems. Contact our Legionella Control Systems engineering experts to learn more.