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For a combination sink and tray fixture, what is the minimum size requirement for the trap?

  1. 1 inch

  2. 1 1/2 inches

  3. 2 inches

  4. 2 1/2 inches

The correct answer is: 1 1/2 inches

The minimum size requirement for the trap on a combination sink and tray fixture is 1 1/2 inches. This specification is designed to ensure adequate drainage and to handle the maximum potential flow of wastewater generated by the combination fixture. A trap of this size allows for efficient water flow and helps prevent clogs, which is essential for maintaining sanitary conditions in plumbing systems. While larger trap sizes might be permissible for different fixtures or applications, the 1 1/2-inch size is specifically chosen based on the design and hydraulic considerations of combination sinks and trays. The sizing of traps is critical to prevent issues such as backups and odors from the plumbing system.