When assembling a Schedule 40 PVC DWV system, a plumber identifies a need to join a 2-inch (50 mm) PVC pipe to an existing 2-inch (50 mm) ABS pipe. Which of the following is the code-compliant and recommended method for making this dissimilar plastic pipe connection?

Question: When assembling a Schedule 40 PVC DWV system, a plumber identifies a need to join a 2-inch (50 mm) PVC pipe to an existing 2-inch (50 mm) ABS pipe. Which of the following is the code-compliant and recommended method for making this dissimilar plastic pipe connection?

Answer options: ✅ Using a mechanical coupling with elastomeric gaskets (e.g., a transition coupling).

• Applying a universal solvent cement designed for both PVC and ABS.
• Heating both pipe ends and press-fitting them together.
• Wrapping the joint with several layers of solvent-resistant tape.

Correct answer: Using a mechanical coupling with elastomeric gaskets (e.g., a transition coupling).

Explanation: Joining dissimilar plastics like PVC and ABS requires a mechanical transition coupling with elastomeric gaskets, as per plumbing codes, to ensure a watertight and durable connection. Universal solvent cements are generally not permitted for creating structural bonds between these two plastic types due to their different chemical compositions, and heating or taping are not code-compliant for such connections.