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 vent that runs horizontally to outside air

Answer

A mechanical vent device

Answer

A vent serving only one fixture

Question 2

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

Accepted Answer

12 inches

Answer

2 inches

Answer

6 inches

Answer

18 inches

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

Branch drain

Answer

Building sewer

Answer

Waste arm

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

Sanitary tee

Answer

Short-turn 90-degree elbow

Answer

Cross fitting

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

Waste that bypasses the main drain stack

Answer

Greywater reused from sinks

Answer

Waste from outdoor fixtures

Question 6

What prevents sewer gases from entering a building through a floor drain that is rarely used?

Accepted Answer

A trap primer or trap seal preservative

Answer

The weight of the drain cover

Answer

Negative pressure in the drain

Answer

The floor drain's check valve