Journeyman Plumbers Exam Backflow Prevention 2

Question 1

Which backflow preventer is required when a garden hose is connected to a boiler drain valve on a potable water system?

Accepted Answer

Atmospheric vacuum breaker (AVB)

Answer

An atmospheric vacuum breaker is suitable for hose bibb connections on potable water systems where there is no continuous pressure downstream.

Question 2

A cross-connection is best defined as:

Accepted Answer

Any physical connection between a potable and non-potable water supply

Answer

A cross-connection is any physical link between a potable water supply and a potential source of contamination or pollution.

Question 3

What is the minimum height above the flood level rim that a pressure vacuum breaker (PVB) must be installed?

Accepted Answer

12 inches

Answer

A pressure vacuum breaker must be installed a minimum of 12 inches above the highest downstream outlet or flood level rim.

Question 4

Which of the following applications requires a reduced pressure zone (RPZ) backflow preventer?

Accepted Answer

Fire sprinkler system using antifreeze

Answer

Fire sprinkler systems using antifreeze present a high-hazard condition requiring an RPZ because antifreeze is toxic if it enters the potable supply.

Question 5

The check valves inside a double check valve assembly (DCVA) must each be capable of holding against how much static pressure?

Accepted Answer

10 psi

Answer

Each check valve in a DCVA must independently hold against a minimum of 10 psi of backpressure.

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