Journeyman Plumbers Exam Venting and Backflow Prevention 5

Question 1

Which plumbing code section governs the maximum number of fixture units allowed on a wet-vented horizontal branch?

Accepted Answer

Wet vent fixture unit table

Answer

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.

Question 2

A combination drain and vent system (CD&V) is most commonly used for:

Accepted Answer

Floor drains and sinks in slab-on-grade construction

Answer

CD&V systems are designed for floor drains and similar fixtures in slab-on-grade construction where conventional venting is difficult to install.

Question 3

What is the purpose of the air gap in a dishwasher drain connection?

Accepted Answer

To prevent backflow of contaminated water into the dishwasher

Answer

The dishwasher air gap provides a physical break in the drain line to prevent contaminated sink water from siphoning back into the dishwasher.

Question 4

Under the IPC, what is the maximum vertical distance a trap arm may run before connecting to the vent?

Accepted Answer

The developed length limit from the sizing table

Answer

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.

Question 5

A reduced pressure zone (RPZ) assembly must be installed in which orientation?

Accepted Answer

Horizontal or vertical per manufacturer approval

Answer

RPZ assemblies may be installed horizontally or vertically depending on the manufacturer's listing and local code requirements.

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Venting and Backflow Prevention 5