Venting and Backflow Prevention Flashcards
7 cards from real Journeyman Plumbers 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 Venting and Backflow Prevention flashcards as text
An island fixture vent must loop to within how many inches of the underside of the counter?
Answer: 6 inches
The island fixture vent must loop up to within 6 inches of the underside of the counter top before dropping back to connect to the drain.
What is the maximum developed length of a 2-inch vent pipe serving a single water closet?
Answer: 60 feet
Under the IPC, a 2-inch vent pipe serving a single water closet has a maximum developed length of 60 feet.
A pressure vacuum breaker (PVB) differs from an atmospheric vacuum breaker (AVB) in that a PVB:
Answer: Can be installed under continuous pressure
A pressure vacuum breaker can remain under continuous supply pressure, whereas an atmospheric vacuum breaker must be de-pressurized for at least 12 hours per day.
Where must an air admittance valve (AAV) NOT be installed?
Answer: Below grade or in a sealed space without air
AAVs require access to air to function; they cannot be installed below grade or in any sealed space where air is unavailable.
Which fixture is permitted to wet vent under most plumbing codes?
Answer: Bathroom group (lavatory, water closet, tub) on a single floor
A bathroom group on a single floor is the classic application of wet venting, where the lavatory drain serves as both a drain and a vent for the water closet.
What is the minimum horizontal distance from a vent terminal opening to any window or door that can be opened?
Answer: 3 feet
Vent terminal openings must be located at least 3 feet from any openable window, door, or other opening into the building.
A double-check valve assembly (DCVA) is appropriate for which hazard level cross-connection?
Answer: Low hazard (non-toxic, non-health threat)
DCVAs are suitable for low-hazard cross-connections where backflow could cause aesthetic issues but not health risks; high-hazard applications require an RPZ.