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Drain, Waste, & Vent Systems Flashcards

7 cards from real Master Plumber Exam practice questions. Tap to flip, then mark Knew It or Still Learning โ€” missed cards come back until you master them.

Read the first 7 Drain, Waste, & Vent Systems flashcards as text
  1. Which material is NOT permitted for underground drain piping inside a building per the IPC?

    Answer: Galvanized steel

    Galvanized steel is not listed by the IPC as an approved material for underground drain, waste, and vent piping due to corrosion susceptibility.

  2. What is the maximum number of fixture units that can drain into a 4-inch horizontal branch drain?

    Answer: 216 fixture units

    Per IPC drainage fixture unit tables, a 4-inch horizontal branch drain can handle a maximum of 216 fixture units.

  3. An air admittance valve (AAV) may NOT be used as the sole vent for which application under the IPC?

    Answer: The main stack vent termination to outside air

    At least one vent in every building must extend to open outdoor air; an AAV cannot replace the required outdoor vent termination for the entire building's DWV system.

  4. What is the minimum diameter for a building sewer serving a single-family home with up to 21 drainage fixture units?

    Answer: 4 inches

    The IPC requires a minimum 4-inch building sewer for a single-family dwelling regardless of the calculated fixture unit load.

  5. A sanitary tee fitting may be used in which orientation for drain connections?

    Answer: Upright with flow entering from the side branch vertically downward

    A sanitary tee is approved only in the upright position where the branch enters from the side and flow descends into the vertical leg, not laid on its back for horizontal connections.

  6. When a drain pipe transitions from vertical to horizontal, which fitting provides the most hydraulically efficient change of direction?

    Answer: Long-sweep 1/4 bend

    A long-sweep 1/4 bend provides the gentlest transition from vertical to horizontal flow, minimizing turbulence and the risk of blockage.

  7. What is the term for a vent that connects multiple trap arms to a single common vent pipe in a battery of fixtures?

    Answer: Circuit vent

    A circuit vent connects the trap arms of a series of fixtures on a horizontal branch to a single vent riser, commonly used for back-to-back fixtures or fixture batteries.