Journeyman Plumbers Exam Drainage, Waste, and Venting 4

Question 1

Which fitting is required when a drain changes direction from vertical to horizontal?

Accepted Answer

Long-sweep 1/4 bend or combination wye and 1/8 bend

Answer

A long-sweep 1/4 bend or a combination wye and 1/8 bend is required when transitioning from vertical to horizontal to ensure smooth, non-turbulent flow.

Question 2

What is the maximum vertical distance a fixture drain may drop before connecting to the trap arm?

Accepted Answer

The trap arm must be level or pitched to drain only

Answer

The trap arm must be level or pitched toward the drain at no more than 1/4 inch per foot — no section between the trap and vent may be vertical.

Question 3

A 3-inch soil stack may NOT receive the discharge from which fixture?

Accepted Answer

Water closet

Answer

Water closets require a minimum 3-inch drain, but the stack receiving water closet discharge must also be at least 3 inches — however the trap itself must be 3 inches minimum, making the stack size at least 3 inches; a 2-inch stack cannot receive a water closet.

Question 4

In a DWV system, what does the term 'developed length' mean?

Accepted Answer

The total length measured along the centerline of the pipe including fittings

Answer

Developed length is the total length measured along the centerline of the pipe, following all bends and offsets, used for calculating vent lengths and trap arm limits.

Question 5

Which condition is considered a cross-connection in a DWV system?

Accepted Answer

A drain pipe connected directly to a potable water supply pipe

Answer

A cross-connection occurs when a drain pipe is directly connected to a potable water supply, creating a potential for contamination.

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Drainage, Waste, and Venting 4