IPC - International Plumbing Code Vents and Venting Questions and Answers

Question 1

According to the IPC, what is the minimum size for an individual vent pipe?

Accepted Answer

One-half the diameter of the drain served, but not less than 1 1/4 inches

Answer

1 inch

Answer

The same size as the drain pipe it serves

Answer

1 1/2 inches

Question 2

A plumber is installing a kitchen sink with a 2-inch drain. Based on the IPC, what is the maximum allowable horizontal distance from the fixture trap to its vent, assuming a slope of 1/4 inch per foot?

Accepted Answer

8 feet

Answer

5 feet

Answer

6 feet

Answer

10 feet

Question 3

Which of the following is a requirement for installing an individual vent that offsets horizontally?

Accepted Answer

The vent must rise vertically to a minimum of 6 inches above the flood level rim of the fixture served before offsetting horizontally.

Answer

The horizontal offset must be below the fixture's flood level rim.

Answer

The vent must connect to the drain with a sanitary tee.

Answer

Horizontal offsets for individual vents are strictly prohibited by the IPC.

Question 4

A multi-story building has a single drainage stack. At what point is a vent stack required for this drainage stack according to the IPC?

Accepted Answer

When the stack has five or more branch intervals.

Answer

When the stack serves more than two fixtures.

Answer

When the stack is taller than 3 stories.

Answer

When the stack has two or more branch intervals.

Question 5

A plumber needs to vent a group of 8 lavatories arranged in a line (battery). Which of the following venting methods would be most appropriate and efficient for this scenario under the IPC?

Accepted Answer

A circuit vent

Answer

A combination waste and vent system

Answer

An Air Admittance Valve for each lavatory

Answer

Individual vents for each of the 8 lavatories

Question 6

Under the IPC, an individual vent with a developed length of 50 feet is being installed. What modification is required for this vent pipe?

Accepted Answer

It must be increased by one nominal pipe size for its entire length.

Answer

It must be supported every 4 feet.

Answer

It requires a cleanout at its base.

Answer

No modification is required based on length.