Plumbing Drainage, Waste & Vent (DWV)

Question 1

What is the primary purpose of a vent pipe in a plumbing system?

Accepted Answer

To maintain air pressure and prevent siphoning of trap seals

Answer

To increase water pressure

Answer

To drain condensation

Answer

To supply fresh water to fixtures

Question 2

What is the minimum water seal depth required in a standard P-trap?

Accepted Answer

2 inches

Answer

1 inch

Answer

3 inches

Answer

4 inches

Question 3

What type of trap is prohibited in most US plumbing codes?

Accepted Answer

S-trap

Answer

P-trap

Answer

Running trap

Answer

Drum trap

Question 4

What does 'wet venting' mean in a plumbing system?

Accepted Answer

A single pipe that serves as both a drain and a vent

Answer

Using water to flush vent pipes

Answer

Installing vent pipes in wet walls

Answer

Venting through a plumbing appliance

Question 5

What is the term for a fitting that connects a branch drain to a vertical stack?

Accepted Answer

Sanitary tee

Answer

Cleanout

Answer

P-trap

Answer

Wye fitting

Question 6

What is the maximum distance a lavatory trap can be from its vent?

Accepted Answer

4 feet

Answer

2 feet

Answer

6 feet

Answer

8 feet