BACKFLOW CONTROL METHODS
EXAM QUESTIONS AND ANSWERS
Name the backflow control methods - Correct Answers -1) Air gap
2) Barometric loop
3) Atmospheric vacuum breaker
4) Hose bibb vacuum breaker
5) Pressure vacuum breaker
6) Double check with intermediate atmospheric vent
7) Double check valve
8) Double check detector check
9)Residential dual check
10) Reduced pressure principle backflow preventor
Air gap characteristics - Correct Answers -Air gaps are non-mechanical backflow
preventers that are very effective devices to be used where either backsiphonage or
backpressure conditions exists
In general, the air gap must be twice the supple pipe diameter but never less than one
inch
An air gap, although effective backflow preventer when used to prevent Backsiphonage
and backpressure conditions, does interrupt the piping flow with corresponding loss of
pressure for subsequent use. Consequently, air gaps are used for end of line service
where reservoirs or storage tanks are desired
Barometric Loop - Correct Answers -The barometric loop consists of a continuous
section of supply piping that abruptly rises to a height of approximately 35 feet and then
returns back down to the orrigintaig level. It is a loop in the piping system that effective
protects against BACKSIPHONAGE. It may not be used to protect agasinst
BACKPRESSURE.
Its operation is based upon the principle that a water column will not rise above 33.9
feet. Loops are 35 feet high.
Double check valve - Correct Answers -essentially two check valves coupled within one
body and furnished with test cocks and two tightly closing gate
valves
EXAM QUESTIONS AND ANSWERS
Name the backflow control methods - Correct Answers -1) Air gap
2) Barometric loop
3) Atmospheric vacuum breaker
4) Hose bibb vacuum breaker
5) Pressure vacuum breaker
6) Double check with intermediate atmospheric vent
7) Double check valve
8) Double check detector check
9)Residential dual check
10) Reduced pressure principle backflow preventor
Air gap characteristics - Correct Answers -Air gaps are non-mechanical backflow
preventers that are very effective devices to be used where either backsiphonage or
backpressure conditions exists
In general, the air gap must be twice the supple pipe diameter but never less than one
inch
An air gap, although effective backflow preventer when used to prevent Backsiphonage
and backpressure conditions, does interrupt the piping flow with corresponding loss of
pressure for subsequent use. Consequently, air gaps are used for end of line service
where reservoirs or storage tanks are desired
Barometric Loop - Correct Answers -The barometric loop consists of a continuous
section of supply piping that abruptly rises to a height of approximately 35 feet and then
returns back down to the orrigintaig level. It is a loop in the piping system that effective
protects against BACKSIPHONAGE. It may not be used to protect agasinst
BACKPRESSURE.
Its operation is based upon the principle that a water column will not rise above 33.9
feet. Loops are 35 feet high.
Double check valve - Correct Answers -essentially two check valves coupled within one
body and furnished with test cocks and two tightly closing gate
valves
