Journeyman Plumbers Exam Drainage, Waste, and Vent Systems 3

Question 1

Which of the following fixtures is assigned the highest drainage fixture unit (DFU) value under the IPC?

Accepted Answer

Water closet (flush tank)

Answer

A flush-tank water closet is rated at 3 DFUs, which is higher than a lavatory (1), bathtub (2), or kitchen sink (2).

Question 2

What type of vent is installed downstream of a fixture trap and connects to the vent stack above the fixture's flood level rim?

Accepted Answer

Individual vent (back vent)

Answer

An individual vent (also called a back vent or revent) connects the fixture's trap arm to the vent stack and runs upward past the fixture's flood level rim.

Question 3

An island fixture vent loop is required when:

Accepted Answer

A sink or similar fixture is installed in an island where a standard vent cannot go up through a wall

Answer

Island fixture vent loops route the vent piping under the floor and back up alongside the drain when there is no adjacent wall to run a conventional vent.

Question 4

What is the minimum size of a vent stack serving a soil stack that receives discharge from water closets?

Accepted Answer

3 inches

Answer

When water closets connect to the soil stack, the vent stack must be at least 3 inches in diameter per IPC sizing requirements.

Question 5

A crown vent is prohibited because:

Accepted Answer

Solids can accumulate and block the vent opening at the top of the trap

Answer

A crown vent connects at the crown (top) of the trap, where waste material can collect and plug the vent, rendering it ineffective.

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Drainage, Waste, and Vent Systems 3