Journeyman Plumbers Drainage, Waste, and Vent Systems Questions and Answers

Question 1

According to most plumbing codes, what is the required range for a fixture trap's liquid seal depth?

Accepted Answer

2 inches to 4 inches

Answer

1 inch to 3 inches

Answer

3 inches to 5 inches

Answer

4 inches to 6 inches

Question 2

A plumber is installing the drain for a kitchen sink, which has a 1-1/2 inch P-trap. What is the maximum horizontal distance the trap arm can be from the vent fitting?

Accepted Answer

3 feet 6 inches

Answer

5 feet

Answer

6 feet

Answer

8 feet

Question 3

Which of the following is the primary purpose of a vent in a drainage system?

Accepted Answer

To equalize pressure and protect trap seals

Answer

To provide a means of cleaning the drain line

Answer

To increase the velocity of the wastewater

Answer

To filter out solid waste materials

Question 4

A journeyman plumber is planning a horizontal DWV (Drainage, Waste, and Vent) line using 4-inch diameter pipe. What is the minimum required slope for this pipe?

Accepted Answer

1/8 inch per foot

Answer

1/16 inch per foot

Answer

1/2 inch per foot

Answer

1/4 inch per foot

Question 5

When installing a wet vent for a bathroom group (e.g., toilet, lavatory, and bathtub), which of the following is a critical requirement according to most plumbing codes?

Accepted Answer

All fixtures served by the wet vent must be on the same floor level.

Answer

The wet-vented section must be two pipe sizes larger than the largest fixture drain.

Answer

Only fixtures on different floor levels can be connected to the wet vent.

Answer

The toilet must always be the most upstream fixture connected to the wet vent.

Question 6

Cleanouts are required in a drainage system to allow for access. For a horizontal drainage pipe that is 100 feet long, where must cleanouts be located?

Accepted Answer

At the upper terminal and for each 100 feet, or fraction thereof, of developed length.

Answer

At the upper terminal and for each 50 feet of developed length.

Answer

Only at the upper terminal end of the pipe.

Answer

Only at changes of direction greater than 90 degrees.