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Backflow Exam Study Guide 100% verified.
Low Hazard - ANS An actual or potential threat to the potable water system whereby the risk
from backflow would be limited to the pollution of the potable water system by an aesthetically
objectionable but non-toxic substance, such as beverages, foods, or other non-toxic substances;
pollution hazard (aesthetically objectionable)
High Hazard - ANS An actual or potential threat of contamination of the potable water
system that would present a threat to the health of the consumer; system hazard (may cause
damage to the system piping); health hazard (is a threat to the health of the water user)
Severe High Hazard - ANS presents a threat of death
Absolute Pressure - ANS the total pressure; gauge pressure plus atmospheric pressure.
Absolute pressure is generally measured in pounds per square inch, and is indicated as pounds
per square in absolute (psia)
Air-Gap Separation - ANS The unobstructed vertical distance through the free atmosphere
between the lowest opening from any pipe, or outlet supplying water to a tank, plumbing
fixture, or other device, and the flood level rim of the receptacle
Approved Air-Gap Separation - ANS As approved air-gap separation is a distance through the
free atmosphere equal to 2 times the nominal diameter of the supply pipe discharge opening,
but never less than 1 inch
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Atmospheric Pressure - ANS The pressure exerted by the weight of the atmosphere (14.7
psig) at sea level. As the elevation above sea level increases, the atmospheric pressure
decreases
Atmospheric Vacuum Breaker - ANS A mechanical device consisting of a float check valve and
an air-inlet port designed to prevent backsiphonage
Auxiliary Water System - ANS Any water system on or available to the premises other than
the public water system. These auxiliary water systems shall include used water or water from a
source other than the public water system, such as wells, cisterns or open reservoirs that are
equipped with pumps or other prime movers, including gravity
Backflow - ANS The unintentional reversal of the normal direction of flow in a potable water
system that may result in the pollution or contamination of the system by a liquid, gas, solids,
and mixtures
Backflow Prevention Device - ANS Any device, method, or type of construction that is used to
prevent a backflow condition into a potable water system
Backpressure Backflow - ANS A reversal of the normal direction of flow in a water system
due to an increase in downstream pressure above that of the supply pressure. The greater
pressure can cause a non-potable substance to backflow into the potable water system through
unprotected cross-connections
Backsiphonage Backflow - ANS A reversal of the normal direction of flow in the piping due to
a drop in supply pressure, a vacuum, or a negative pressure in the supply piping
Booster Pump - ANS Any device which is intended to increase the in-line water pressure
Bypass - ANS Any arrangement of pipes, plumbing, or hoses which are designed to divert the
flow around an installed backflow prevention device through which the flow normally passes
Backflow Exam Study Guide 100% verified.
Low Hazard - ANS An actual or potential threat to the potable water system whereby the risk
from backflow would be limited to the pollution of the potable water system by an aesthetically
objectionable but non-toxic substance, such as beverages, foods, or other non-toxic substances;
pollution hazard (aesthetically objectionable)
High Hazard - ANS An actual or potential threat of contamination of the potable water
system that would present a threat to the health of the consumer; system hazard (may cause
damage to the system piping); health hazard (is a threat to the health of the water user)
Severe High Hazard - ANS presents a threat of death
Absolute Pressure - ANS the total pressure; gauge pressure plus atmospheric pressure.
Absolute pressure is generally measured in pounds per square inch, and is indicated as pounds
per square in absolute (psia)
Air-Gap Separation - ANS The unobstructed vertical distance through the free atmosphere
between the lowest opening from any pipe, or outlet supplying water to a tank, plumbing
fixture, or other device, and the flood level rim of the receptacle
Approved Air-Gap Separation - ANS As approved air-gap separation is a distance through the
free atmosphere equal to 2 times the nominal diameter of the supply pipe discharge opening,
but never less than 1 inch
, ©THESTAR 2025 ALL RIGHTS RESERVED
Atmospheric Pressure - ANS The pressure exerted by the weight of the atmosphere (14.7
psig) at sea level. As the elevation above sea level increases, the atmospheric pressure
decreases
Atmospheric Vacuum Breaker - ANS A mechanical device consisting of a float check valve and
an air-inlet port designed to prevent backsiphonage
Auxiliary Water System - ANS Any water system on or available to the premises other than
the public water system. These auxiliary water systems shall include used water or water from a
source other than the public water system, such as wells, cisterns or open reservoirs that are
equipped with pumps or other prime movers, including gravity
Backflow - ANS The unintentional reversal of the normal direction of flow in a potable water
system that may result in the pollution or contamination of the system by a liquid, gas, solids,
and mixtures
Backflow Prevention Device - ANS Any device, method, or type of construction that is used to
prevent a backflow condition into a potable water system
Backpressure Backflow - ANS A reversal of the normal direction of flow in a water system
due to an increase in downstream pressure above that of the supply pressure. The greater
pressure can cause a non-potable substance to backflow into the potable water system through
unprotected cross-connections
Backsiphonage Backflow - ANS A reversal of the normal direction of flow in the piping due to
a drop in supply pressure, a vacuum, or a negative pressure in the supply piping
Booster Pump - ANS Any device which is intended to increase the in-line water pressure
Bypass - ANS Any arrangement of pipes, plumbing, or hoses which are designed to divert the
flow around an installed backflow prevention device through which the flow normally passes
