Joints between different metallic piping materials shall be made with approved dielectric fittings or brass converter fittings.

• A. True
• B. False
• C. Not specified
• D. Only in some cases

Answer: (A)

When metals of different types are joined, galvanic corrosion can occur because dissimilar metals have different electrochemical potentials. In HVAC systems, moisture or other electrolytes can allow current to flow between the metals, causing one to corrode at the joint. Using approved dielectric fittings inserts a non-conductive barrier between the metals, completely isolating them so no galvanic current can flow. Brass converter fittings provide a transition between materials, reducing direct metal-to-metal contact and breaking the galvanic path while still forming a reliable, sealed joint. Because these methods are designed to prevent galvanic corrosion, they are the approved ways to join different metallic piping materials, making the statement true.