PC Plumber Water & Drainage 4

Question 1

What is the fixture unit value assigned to a standard toilet (water closet) for drainage load calculations?

Accepted Answer

4 DFUs

Answer

2 DFUs

Answer

6 DFUs

Answer

8 DFUs

Question 2

A backwater valve (backflow preventer) installed on a building drain protects against which condition?

Accepted Answer

Sewage backing up from the municipal sewer into the building

Answer

High water pressure from the supply main

Answer

Air pressure surges in the vent system

Answer

Cold water freezing in outdoor drain lines

Question 3

What is the maximum allowable working pressure for standard Schedule 40 PVC pressure pipe at 73°F?

Accepted Answer

160 psi

Answer

100 psi

Answer

200 psi

Answer

315 psi

Question 4

When solvent cementing PVC pipe, what must be applied to both the pipe and fitting before the solvent cement?

Accepted Answer

Purple primer

Answer

Teflon tape

Answer

Pipe dope

Answer

Silicone lubricant

Question 5

A grease trap is required when installing commercial kitchen drainage. Where is it installed?

Accepted Answer

Between the kitchen fixtures and the sanitary drain system

Answer

In the municipal sewer main

Answer

In the building sewer after it exits the foundation

Answer

On the roof vent stack

Question 6

What is a 'critical level' (C-L) marking on a backflow preventer?

Accepted Answer

The flood level line of the device, indicating minimum installation height above the flood rim

Answer

The maximum flow rate the device can handle

Answer

The level below which the device must be installed to prevent flooding

Answer

The pressure rating at which the device opens

Question 7

Which venting method uses a single vent pipe to serve multiple fixtures on the same floor level connected to a common horizontal drain?

Accepted Answer

Circuit venting

Answer

Individual venting

Answer

Stack venting

Answer

Combination waste and vent