Journeyman Plumbers Exam Venting and Backflow Prevention 2

Question 1

What is the minimum diameter for a vent pipe serving a 3-inch drain pipe under the IPC?

Accepted Answer

1.5 inches

Answer

The vent pipe must be at least half the diameter of the drain it serves, with a minimum of 1.25 inches, making 1.5 inches the standard minimum for a 3-inch drain.

Question 2

A circuit vent is connected to a horizontal branch drain at what location relative to the fixture connections?

Accepted Answer

Downstream of the last fixture

Answer

A circuit vent connects to the horizontal branch drain downstream (below) the last fixture connection on that branch.

Question 3

What type of backflow preventer is required on a hose bibb supplying potable water?

Accepted Answer

Vacuum breaker

Answer

A hose-connection vacuum breaker (HCVB) is required on hose bibbs to prevent siphonage of potentially contaminated water back into the supply.

Question 4

Under which condition is a wet vent system NOT permitted?

Accepted Answer

When the drain serves more than one floor

Answer

Wet venting is generally limited to a single story; drains serving fixtures on multiple floors require conventional venting.

Question 5

Which device provides the highest level of backflow protection and is required for high-hazard connections?

Accepted Answer

Reduced pressure zone (RPZ) assembly

Answer

The reduced pressure zone assembly is the highest-rated mechanical backflow preventer and is required for high-hazard cross-connections such as chemical feed lines.

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Venting and Backflow Prevention 2