On a plumbing blueprint, which symbol indicates a union?

• A. Drain
• B. Tee
• C. Cleanout
• D. Union

Answer: (D)

A union is a detachable fitting that connects two pipe runs so they can be separated for maintenance. On plumbing blueprints, this is shown with a symbol that looks like a short straight section flanked by two small circles (representing the nut assemblies that hold the two halves together). This visual cue highlights the removable nature of the joint, indicating you can unscrew and separate the pipes without cutting. This distinguishes it from other symbols you might see: a drain symbol marks a drainage path, a Tee shows a branching junction, and a cleanout marks access for clearing blockages.