CH. 5 - METHODS & MECHANISM OF
PREVENTING BACKFLOW EXAM
A assembly is the entire Backflow prevention unit including:
a. Testcocks
b. Shut off valves, test cocks & mechanism.
c. Shut off valves & mechanism. - Correct Answers -b. Not only the mechanism that
actually prevents backflow but also the shut off valves of test cocks.
Approved assemblies must be shipped from manufacture as:
a. Half a unit.
b. Not assembled.
c. One complete unit. - Correct Answers -c. One complete unit
Shut-off valves must be:
a. Closed with shut off valves,
b. Resilient seated and have full-flow characteristics.
c. May leak some. - Correct Answers -b. Resilient seated and have full-flow
characteristics
RP under normal flow relief valve will remain:
a. Open
b. Closed
c. Drip - Correct Answers -b. Closed
RP during backpressure conditions in which there is an increase of pressure on the
customer side what will the second check valve do to prevent backflow.
a. Open a little to release the pressure.
b. Hold Tight
c. The relief valve will dump. - Correct Answers -b. Hold tight
RP under backsiphonage condition in which the supply line pressure drops towards
zero pressure exerted on the supply side of the diaphragm falls below the required to
keep the relief valve closed what happens:
a. #2 check valve opens to relieve pressure.
b. #1 check valve opens to relieve pressure.
c. The relief valve opens an air gap is created to prevent backflow. - Correct Answers -
c. The relief valve opens an air gap is created to prevent backflow
Atmospheric Vacuum Breaker (AVB) are approved by:
, a. A.S.S.E (American Society of Sanitary Engineering)
b. Plumbers.
c. Local government. - Correct Answers -a. Are the simplest type of mechanical
backflow preventer that are currently approved by the A.S.S.E (american society of
sanitary engineering).
AVB can be used for protection against:
a. Backsiphnoage only.
b. Backpressure only.
c. Backpressure and Backsiphnoage only. - Correct Answers -a. Backsiphonage but not
against backpressure
AVB during Backsiphonage: when the water pressure falls below atmospheric pressure
the disc float on the AVB will do what:
a. Falls and let air enter the top to form an Air Gap.
b. Stay fixed to let water flow through.
c. Falls and let's air into the top to stop backpressure - Correct Answers -a. Falls and let
air enter the top to form an Air Gap
AVB must be installed how many inches the highest point in the system.
a. 3 inches.
b. 12 inches
c. 6 inches - Correct Answers -c. 6 inches
Hose Bibb Vacuum Breakers (HBVB) can be used to prevent:
a. Backpressure.
b. Backsiphnoage but not Backpressure.
c. Backpressure and Backsiphnoage - Correct Answers -B. Backsiphonage but not
Backpressure.
Pressure Vacuum Breaker (PVB) is an assembly instead of a device:
a. True
b. False - Correct Answers -a. True
PVB has:
a. Shut off valve and a test cock.
b. 2 test cocks.
c. 2 shut off valves & 2 test cocks. - Correct Answers -c. 2 shut off valves and 2 test
cocks
PVB Cannot be subject to:
a. Backsiphnoage.
b. Backpressure & Backsiphnoage
c. Backpressure. - Correct Answers -c. Backpressure
AVB must not have any shut off valves:
PREVENTING BACKFLOW EXAM
A assembly is the entire Backflow prevention unit including:
a. Testcocks
b. Shut off valves, test cocks & mechanism.
c. Shut off valves & mechanism. - Correct Answers -b. Not only the mechanism that
actually prevents backflow but also the shut off valves of test cocks.
Approved assemblies must be shipped from manufacture as:
a. Half a unit.
b. Not assembled.
c. One complete unit. - Correct Answers -c. One complete unit
Shut-off valves must be:
a. Closed with shut off valves,
b. Resilient seated and have full-flow characteristics.
c. May leak some. - Correct Answers -b. Resilient seated and have full-flow
characteristics
RP under normal flow relief valve will remain:
a. Open
b. Closed
c. Drip - Correct Answers -b. Closed
RP during backpressure conditions in which there is an increase of pressure on the
customer side what will the second check valve do to prevent backflow.
a. Open a little to release the pressure.
b. Hold Tight
c. The relief valve will dump. - Correct Answers -b. Hold tight
RP under backsiphonage condition in which the supply line pressure drops towards
zero pressure exerted on the supply side of the diaphragm falls below the required to
keep the relief valve closed what happens:
a. #2 check valve opens to relieve pressure.
b. #1 check valve opens to relieve pressure.
c. The relief valve opens an air gap is created to prevent backflow. - Correct Answers -
c. The relief valve opens an air gap is created to prevent backflow
Atmospheric Vacuum Breaker (AVB) are approved by:
, a. A.S.S.E (American Society of Sanitary Engineering)
b. Plumbers.
c. Local government. - Correct Answers -a. Are the simplest type of mechanical
backflow preventer that are currently approved by the A.S.S.E (american society of
sanitary engineering).
AVB can be used for protection against:
a. Backsiphnoage only.
b. Backpressure only.
c. Backpressure and Backsiphnoage only. - Correct Answers -a. Backsiphonage but not
against backpressure
AVB during Backsiphonage: when the water pressure falls below atmospheric pressure
the disc float on the AVB will do what:
a. Falls and let air enter the top to form an Air Gap.
b. Stay fixed to let water flow through.
c. Falls and let's air into the top to stop backpressure - Correct Answers -a. Falls and let
air enter the top to form an Air Gap
AVB must be installed how many inches the highest point in the system.
a. 3 inches.
b. 12 inches
c. 6 inches - Correct Answers -c. 6 inches
Hose Bibb Vacuum Breakers (HBVB) can be used to prevent:
a. Backpressure.
b. Backsiphnoage but not Backpressure.
c. Backpressure and Backsiphnoage - Correct Answers -B. Backsiphonage but not
Backpressure.
Pressure Vacuum Breaker (PVB) is an assembly instead of a device:
a. True
b. False - Correct Answers -a. True
PVB has:
a. Shut off valve and a test cock.
b. 2 test cocks.
c. 2 shut off valves & 2 test cocks. - Correct Answers -c. 2 shut off valves and 2 test
cocks
PVB Cannot be subject to:
a. Backsiphnoage.
b. Backpressure & Backsiphnoage
c. Backpressure. - Correct Answers -c. Backpressure
AVB must not have any shut off valves:
