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 cleanout is an access plug installed in drain lines that allows a plumber to clear blockages without removing pipe sections, required at direction changes and at specified intervals.

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

An AAV (Studor valve) allows air into the drain system to equalize pressure, functioning as a vent without running pipe through the roof.

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

A 45-degree wye fitting is used to connect horizontal drain branches because it promotes laminar flow and reduces the chance of blockages.

Question 4

What is 'hydraulic gradient' in a drain system?

Accepted Answer

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

Answer

Hydraulic gradient refers to the slope of drain pipes, which must be maintained at the correct pitch to ensure solids are carried along with water to prevent blockages.

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

An individual vent, also called a back vent or revent, connects directly from the fixture trap to the vent stack above the fixture's flood level rim.

Plumbing Practice Test

Plumbing Practice Test

Plumbing Drainage, Waste & Vent (DWV) 2