Backflow / Cross Connection Flashcards
An approved assembly consisting of spring loaded check valves and air inlet valve installed between two resilient seated shutoff valves is:
PVB (pressure vacuum breaker)
An assembly consisting of two spring loaded check valves separated by a differential pressure relief valve is:
A reduced pressure backflow assembly
This backflow assembly consists of two internally loaded check valves (either spring or weight loaded)
DCVA
This assembly consists of an air inlet valve and a spring loaded check valve
PVBA
The relief valve of a RPBA maintains a differential pressure of at least
2 psig
This backflow assembly may also detect water loss or theft on a low hazard service
DCDA (double check detector assembly)
This backflow preventer must not be installed upstream of a shutoff valve
AVB
The air inlet valve of a PVBA must open at or above ___ psig
1
An RPBA installed more than ____ feet above the floor shall have a platform provided for servicing and testing.
5 ft (1500 mm)
Backflow preventer on a water service to protect the purveyor water supply but not the building occupants, referred to as ____ isolation
Premise isolation
The #1 check valve on a RPBA is spring loaded to the ____ position
Closed
The zone of reduced pressure in a RPBA will not be closer than ____ of the ____ pressure
2 psid (13.8 kPa) of the inlet pressure
The relief valve on a RPBA is held closed by
Supply line pressure
The check valves of a DCVA must hold in the direction of flow against
1 psig, equivalent of 27.7” of water column
Any backflow assembly installed in a piping system where debris is a problem should have a ____ installed upstream
Strainer
The relief valve discharges when you close shutoff #2. What is likely the problem?
The #1 check valve is leaking
The second test of the RPBA would be to check which of the following
The #2 check valve
If the #2 shut off valve of a RPBA does not close right, the assembly may still be tested with the help of a ____
Bypass hose
A small drop in the differential pressure when opening the bypass valve, to test check valve #2 of an RPBA would indicate
Disc compression of #2 check valve
When testing a DCVA with sight tubes, the tubes must be marked at ____ to obtain accurate test
28” (712 mm)
When testing a DCVA with sight tubes, the tubes should be _____ long to obtain the correct test head pressure
36” (914 mm)
The first test of the DCVA is
Check valve #1 in direction of flow
During a test of a DCVA we notice that the sight tube connected to test cock #3 is dropping and water is discharging from test cock #4. This indicates
2 check valve is leaking
Which shutoff valve is opened first when completing the test of a DCVA?
Shutoff #1
The second test requirement, when testing a PVBA is the _____ holds tight in the direction of flow
Air inlet valve
If when testing a RPBA the psid reading drops, it his would indicate that the pressure in the zone of reduced pressure is _____
Increasing
The second test requirement of a RPBA is
2 check valve shall hold tight against all pressures in reverse direction
Minimum buffer required for a RPBA?
3 psid
To calculate the buffer of a RPBA ____ the relief valve opening psid from the ____
Subtract, actual psid
What is the minimum number of test report forms required?
3
When testing a RPBA with a 3-valve differential gauge, what is the cause of the relief valve failing to open when opening the LSCV to test the relief valve opening psid?
Shutoff #2 is leaking or not properly closed
When testing a RPBA with a 3 valve differential gauge, what would cause the psid to rise when opening the BPCV while testing the #2 cv in reverse direction?
Leaking shutoff #2 and a backflow condition
