Cross-connection & Backflow: Questions With
Trusted Solutions
CROSS-CONNECTION Correct Answer - any arrangement of
pipes, fittings, fixtures, or devices that connects a nonpotable system
to a potable water system. A physical link between the potable
water supply and a source of pollution or contamination
Cross-connections are classified as Correct Answer - 1. Direct
or permanent (hard plumbed)
2. Indirect or temporary (garden hose next to chemical barrel)
ACTUAL CROSS-CONNECTION Correct Answer - any
arrangement of pipes, fitting, or devices that connects a potable
water supply directly to a non-potable source at all times
BACKFLOW Correct Answer - hydraulic condition, caused by a
difference in pressure, in which non-potable water or other liquids
flow into a potable water system
BACKPRESSURE Correct Answer - A type of backflow where
the condition in which a pump, boiler, or other equipment produces
a pressure greater than the water supply pressure.
BACKSIPHONAGE Correct Answer - A type of backflow where
the condition in which the pressure in the distribution system is less
than the atmospheric pressure, which allows contamination to enter
a water system through cross-connection.
POTENTIAL CROSS-CONNECTION Correct Answer - any
arrangement of pipes, fittings, or devices that indirectly connects a
potable water supply to a non-potable source. This connection may
not be present at all times, but it is always there potentially.
, AIR GAP Correct Answer - Safest& simplest way to prevent
cross connection. Physical separation, not a device. Designed for
high hazard.
in plumbing, 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 container and
the overflow rim of that container.
REDUCED PRESSURE ZONE BACKFLOW-PREVENTER (RPZ)
Correct Answer - a mechanical device consisting of two
independently operating, spring loaded check valves with a reduced
pressure zone (differential relief valve) between the check valves.
Designed to provide maximum protection against both
Backpressure and backsiphonage. Can be used for low/high hazard.
Don't install in pits where relief valve may become submerged.
Should not be installed where vertical access is req'd
DOUBLE CHECK VALVE BACKFLOW-PREVENTER (DCVA) Correct
Answer - a mechanical designed basically the same way as the
reduce pressure zone backflow-preventer but without the relief
valve. If the Check valve #2 doesn't fully seal, then Check valve #1
will "backup" the #2
VACUUM BREAKER Correct Answer - mechanical device that
allows air into the piping system, thereby preventing backflow that
could otherwise be cause by the siphoning action created by a
partial vacuum
The correct protective methods for backflow-prevention devices, in
order of decreasing effectiveness, are Correct Answer - 1. air
gap (high risk hazard protection)
2. REDUCED PRESSURE ZONE BACKFLOW-PREVENTER (RPZ or RP)
Trusted Solutions
CROSS-CONNECTION Correct Answer - any arrangement of
pipes, fittings, fixtures, or devices that connects a nonpotable system
to a potable water system. A physical link between the potable
water supply and a source of pollution or contamination
Cross-connections are classified as Correct Answer - 1. Direct
or permanent (hard plumbed)
2. Indirect or temporary (garden hose next to chemical barrel)
ACTUAL CROSS-CONNECTION Correct Answer - any
arrangement of pipes, fitting, or devices that connects a potable
water supply directly to a non-potable source at all times
BACKFLOW Correct Answer - hydraulic condition, caused by a
difference in pressure, in which non-potable water or other liquids
flow into a potable water system
BACKPRESSURE Correct Answer - A type of backflow where
the condition in which a pump, boiler, or other equipment produces
a pressure greater than the water supply pressure.
BACKSIPHONAGE Correct Answer - A type of backflow where
the condition in which the pressure in the distribution system is less
than the atmospheric pressure, which allows contamination to enter
a water system through cross-connection.
POTENTIAL CROSS-CONNECTION Correct Answer - any
arrangement of pipes, fittings, or devices that indirectly connects a
potable water supply to a non-potable source. This connection may
not be present at all times, but it is always there potentially.
, AIR GAP Correct Answer - Safest& simplest way to prevent
cross connection. Physical separation, not a device. Designed for
high hazard.
in plumbing, 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 container and
the overflow rim of that container.
REDUCED PRESSURE ZONE BACKFLOW-PREVENTER (RPZ)
Correct Answer - a mechanical device consisting of two
independently operating, spring loaded check valves with a reduced
pressure zone (differential relief valve) between the check valves.
Designed to provide maximum protection against both
Backpressure and backsiphonage. Can be used for low/high hazard.
Don't install in pits where relief valve may become submerged.
Should not be installed where vertical access is req'd
DOUBLE CHECK VALVE BACKFLOW-PREVENTER (DCVA) Correct
Answer - a mechanical designed basically the same way as the
reduce pressure zone backflow-preventer but without the relief
valve. If the Check valve #2 doesn't fully seal, then Check valve #1
will "backup" the #2
VACUUM BREAKER Correct Answer - mechanical device that
allows air into the piping system, thereby preventing backflow that
could otherwise be cause by the siphoning action created by a
partial vacuum
The correct protective methods for backflow-prevention devices, in
order of decreasing effectiveness, are Correct Answer - 1. air
gap (high risk hazard protection)
2. REDUCED PRESSURE ZONE BACKFLOW-PREVENTER (RPZ or RP)
