Plumbing Drainage, Waste & Vent (DWV) 2

Question 1

What is a cleanout and where is it required?

Accepted Answer

An access plug that allows clearing of drain line blockages

Answer

A water filter installed at the main line

Answer

A valve that stops sewer gas

Answer

A device that cleans drinking water

Question 2

What is the purpose of an air admittance valve (AAV)?

Accepted Answer

To allow air into the drain system without a traditional vent pipe

Answer

To add air to the water supply for pressure

Answer

To release excess air from hot water lines

Answer

To prevent backflow in supply lines

Question 3

Which fitting should be used when connecting a horizontal drain line to another horizontal drain line at the same elevation?

Accepted Answer

45-degree wye

Answer

Sanitary tee

Answer

Long-sweep 90

Answer

Street elbow

Question 4

What is 'hydraulic gradient' in a drain system?

Accepted Answer

The slope maintained in drain pipes to ensure self-cleaning flow

Answer

The velocity of water in supply lines

Answer

The pressure difference between hot and cold water

Answer

The depth of a trap seal

Question 5

What type of vent connects a fixture's drain to a vent stack at a point above the fixture's flood level rim?

Accepted Answer

Individual vent (back vent)

Answer

Wet vent

Answer

Island vent

Answer

Common vent

Question 6

What is the minimum diameter for a building drain that receives discharge from a water closet (toilet)?

Accepted Answer

3 inches

Answer

2 inches

Answer

4 inches

Answer

6 inches