DWV and Storm Drainage Flashcards
7 cards from real Master Plumber Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 DWV and Storm Drainage flashcards as text
What is the primary purpose of an interceptor (grease trap) in a DWV system?
Answer: To separate fats, oils, and grease from wastewater before it enters the drain
Grease interceptors separate fats, oils, and grease from kitchen wastewater to prevent accumulation and blockages in the sanitary sewer system.
Under the IPC, which of the following fixtures requires an individual vent?
Answer: A water closet in all cases
A water closet must be individually vented because its 3-inch drain carries high solid loads that make shared venting unreliable for trap protection.
What is 'siphonage' in the context of drain traps?
Answer: Negative pressure that draws water out of the trap, breaking the seal
Siphonage occurs when negative (sub-atmospheric) pressure in the drain pipe pulls water out of the trap, destroying the water seal that blocks sewer gases.
A roof drain leader that runs inside the building must be constructed of which material?
Answer: A material approved for DWV service
Inside leaders (conductors) must be made of a material approved for DWV service, such as cast iron, PVC, ABS, or copper, because they are subject to building code requirements.
What is the maximum number of fixture units that a 4-inch horizontal branch drain may carry under the IPC?
Answer: 160 fixture units
Per IPC Table 710.1(2), a 4-inch horizontal branch at 1/4-inch slope may carry a maximum of 160 fixture units.
Which of the following best describes 'back-to-back' fixture venting?
Answer: Two fixtures on opposite sides of a wall sharing a common vent
Back-to-back venting allows two fixtures installed on opposite sides of a common wall to share a single vent pipe, reducing material and labor costs.
What device is installed on a storm drain to prevent backflow from the storm sewer into the building?
Answer: Backwater valve
A backwater valve (backflow preventer) is installed on the storm drain to stop storm sewer surcharge from flowing back into the building's drainage system.