Backflow Prevention Flashcards
7 cards from real Journeyman Plumbers Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Backflow Prevention flashcards as text
Which backflow preventer is required when a garden hose is connected to a boiler drain valve on a potable water system?
Answer: Atmospheric vacuum breaker (AVB)
An atmospheric vacuum breaker is suitable for hose bibb connections on potable water systems where there is no continuous pressure downstream.
A cross-connection is best defined as:
Answer: Any physical connection between a potable and non-potable water supply
A cross-connection is any physical link between a potable water supply and a potential source of contamination or pollution.
What is the minimum height above the flood level rim that a pressure vacuum breaker (PVB) must be installed?
Answer: 12 inches
A pressure vacuum breaker must be installed a minimum of 12 inches above the highest downstream outlet or flood level rim.
Which of the following applications requires a reduced pressure zone (RPZ) backflow preventer?
Answer: Fire sprinkler system using antifreeze
Fire sprinkler systems using antifreeze present a high-hazard condition requiring an RPZ because antifreeze is toxic if it enters the potable supply.
The check valves inside a double check valve assembly (DCVA) must each be capable of holding against how much static pressure?
Answer: 10 psi
Each check valve in a DCVA must independently hold against a minimum of 10 psi of backpressure.
Back-siphonage is caused by:
Answer: A negative pressure (vacuum) on the supply side
Back-siphonage occurs when a negative or sub-atmospheric pressure develops in the supply piping, drawing non-potable water backward.
Which type of backflow is caused by downstream pressure exceeding supply pressure?
Answer: Back-pressure backflow
Back-pressure backflow occurs when downstream pressure (from pumps, boilers, or elevated tanks) exceeds the supply pressure.