Journeyman Plumber ExamPlumbing Code and RegulationsHard

A journeyman plumber is installing a commercial kitchen three-compartment sink. According to the Uniform Plumbing Code (UPC), what is the minimum nominal pipe size for the indirect waste receptor serving this sink?

  1. A4 inches
  2. B1 1/2 inches
  3. C2 inches
  4. D3 inches
Show answer & explanation

Correct answer: D. 3 inches

For a commercial kitchen three-compartment sink, which generates a significant volume of waste, the UPC requires a minimum 3-inch nominal pipe size for the indirect waste receptor. This ensures adequate drainage capacity to prevent overflow and maintain sanitation.

Why the other options are wrong

  • A. 4 inches would be acceptable but is larger than the minimum required, potentially adding unnecessary cost and space.
  • B. 1 1/2 inches is too small for a commercial three-compartment sink's indirect waste receptor and would likely lead to overflow.
  • C. 2 inches is insufficient for the volume of waste from a commercial three-compartment sink.

Commercial Sink Indirect Waste Receptor Size

The minimum diameter of the pipe or funnel that receives indirect waste from commercial fixtures like a three-compartment sink.

  • Prevents direct cross-connection.
  • Sized for fixture's discharge capacity.
  • Critical for commercial sanitation.

Memory trick: Indirect waste flow, for big sinks you know, at least three inches, let the waters go.

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