Plumbing Drainage, Waste & Vent (DWV) 3

Question 1

What is a 'stack vent' in a plumbing system?

Accepted Answer

The extension of a soil or waste stack above the highest fixture connection

Answer

A stack vent is the upper portion of a soil or waste stack that extends above the highest fixture connection and terminates in open air to vent the system.

Question 2

What is the minimum height above a roof surface for a vent terminal (vent through roof)?

Accepted Answer

12 inches

Answer

The IPC requires vent terminals to extend at least 6 inches above the roof surface to prevent blockage by debris, snow, or ice.

Question 3

What is the term for the main vertical drain pipe that carries waste from upper floors to the building drain?

Accepted Answer

Soil stack

Answer

A soil stack is the large vertical pipe that collects waste from fixtures on multiple floors and carries it down to the building drain.

Question 4

Which type of fitting is required when changing direction from horizontal to vertical in a drain system?

Accepted Answer

Long-sweep 90-degree elbow

Answer

A long-sweep 90-degree elbow is required for direction changes in drain lines because its gradual curve maintains flow velocity and prevents blockages.

Question 5

What is 'indirect waste' in plumbing?

Accepted Answer

Discharge from an appliance that drains into an open receptor rather than directly to the drainage system

Answer

Indirect waste is when an appliance (like a dishwasher or HVAC condensate line) drains into an open air gap receptor rather than connecting directly to the sanitary drainage system.

Plumbing Practice Test

Plumbing Practice Test

Plumbing Drainage, Waste & Vent (DWV) 3