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
Which plumbing code section governs the maximum number of fixture units allowed on a wet-vented horizontal branch?
Answer: Wet vent fixture unit table
The wet vent fixture unit table in the IPC sets the maximum drainage fixture units permitted on a wet-vented horizontal branch based on pipe diameter.
A combination drain and vent system (CD&V) is most commonly used for:
Answer: Floor drains and sinks in slab-on-grade construction
CD&V systems are designed for floor drains and similar fixtures in slab-on-grade construction where conventional venting is difficult to install.
What is the purpose of the air gap in a dishwasher drain connection?
Answer: To prevent backflow of contaminated water into the dishwasher
The dishwasher air gap provides a physical break in the drain line to prevent contaminated sink water from siphoning back into the dishwasher.
Under the IPC, what is the maximum vertical distance a trap arm may run before connecting to the vent?
Answer: The developed length limit from the sizing table
The maximum trap-to-vent distance (trap arm length) is determined by the developed length limits in the IPC trap arm sizing table, which varies by pipe diameter.
A reduced pressure zone (RPZ) assembly must be installed in which orientation?
Answer: Horizontal or vertical per manufacturer approval
RPZ assemblies may be installed horizontally or vertically depending on the manufacturer's listing and local code requirements.
Which vent type serves multiple fixtures and allows a single vent pipe to serve as both the vent and the drain for upstream fixtures?
Answer: Wet vent
A wet vent carries both drainage flow from upstream fixtures and serves as the vent for those fixtures, combining two functions in one pipe.
What is the minimum height above finished grade for the installation of an air admittance valve (AAV) in a crawl space?
Answer: 4 inches
AAVs installed in crawl spaces must be located at least 4 inches above the insulation or other materials in the crawl space to ensure proper air access.