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Backflow Exam
| Question | Answer |
|---|---|
| What is the pressure at the base of a 100-foot high stand pipe filled with water? | 43.3 psi |
| A column of water exerts pressure at the bottom of a column due to | The weight of the water |
| What is the primary consideration when deciding whether to install a reduced pressure or a double check valve assembly? | The degree of hazard (secondary considerations are: sidewall clearance and distance from ground level) |
| A cross connection is an actual or potential connection that could allow backflow to occur between a potable water system and a piping system that contains potentially unsafe | Water, steam, gases, chemicals, or unknown substances |
| What are two types of backflow conditions? | Back pressure and backsiphonage |
| A link between a potable water supply and any non potable supply or source is called a | Cross connection |
| A check valve in an approved backflow assembly must be | Resilient seated and loaded to the closed position |
| To avoid creating water hammer, when returning a backflow prevention assembly to service the tester should | Slowly pressurize the assembly and then slowly pressurized the downstream piping |
| During any backsiphonage condition, the check valves of a double check assembly will be | First check closed and second check closed |
| How many tests Cocks must an approved double check valve assembly have? | Four |
| A leaking check valve #2 of a reduced pressure assembly and back pressure will cause this. | The relief valve to discharge |
| What could be the problem if the relief valve of a reduced pressure assembly discharges intermittently? | Large pressure fluctuations |
| Which of the following backflow assemblies contain and independently operating internally loaded check valve and and independently operating loaded air inlet valve located on the check? | A pressure vacuum breaker assembly |
| Which of the following backflow assembly is allowable for use against a contaminant when the backflow could be caused by back pressure? | Reduced pressure backflow assembly |
| While testing check valve #2 of a reduced pressure backflow assembly under back pressure, what would be observed if the second check valve was fouled | Differential on the test kit and discharge from the relief valve |
| What could be determined while testing check valve number one of a double check valve assembly if the gauge reads 0.7 psid? | Check valve #1 is defective |
| What could a tester determine if water is observed flowing from the air inlet of the pressure vacuum breaker prior to starting the test? | Air inlet valve is defective |
| What may be determined when testing the air inlet valve of an approved pressure vacuum breaker if the air inlet valve is observed to open after closing shut off valve #1 | Shutoff valve #2 is leaking with flow downstream |
| When testing a reduced pressure assembly a test kit is used to determine the difference between | |
| High side and low side pressure | |
| While testing a reduced pressure assembly, if the high side hose is connected to test cock #3 and the low side is connected to test cock # 2, the neddele on the test kit gauge will indicate. | No differential |
| A double check valve assembly must be tested every | 12 months |
| When testing the relief Opening Point on a reduced pressure back Flow assembly, the tester needed to open the low control valve more than a 1/4 of a turn. What would this indicate? | Relief valve leaks |
| To test check valve #2 of the reduced pressure assembly for tightness against backpressure, which test kit control valve must be open? | High and Bypass |
| When setting up the reduced pressure assembly for testing, the tester closes shut off valve #2, observed the gauge drop to the low end of the scale,band water discharges from the relief. The tester would then | Stop the test and fail the assembly |
| List the reduced pressure assembly kit control valves | High, low and bypass |
| What is the purpose of the spring in the relief valve assembly of a Reduced Pressure Principle Backflow Preventer? | To force the relief valve open |
| Which of the following is a means of controlling thermal expansion? | Thermal expansion tank |
| What is the maximum height for a perfect vacuum (at sea level) to raise water in a pipe? | 34' |
| During normal operations, the relief on a reduced pressure principle backflow preventer remains closed due to this. | Supply side pressure |
| What protects the potable water supply to a urinal equipped with a flushometer valve? | Atmospheric type vacuum breaker |
| What is the suggested minimum distance between the relief valve discharge Port of a reduced pressure principle backflow preventer assembly and the flood level rim of the surrounding area? | 12 inches |
| What is the type of protection between a potable water system and the building sewer? | Air Gap separation |
| What is the maximum flow temperature for the hose bib vacuum breaker? | 180 degrees |
| What is the purpose of testing the different pressures on a Backflow assembly? | Check spring tension, make sure check valve is seated and record for test reports |
| What is the minimum acceptable pressure differential across check valves when testing a Double Check fire backflow preventer assembly? | 0.5 psi |
| A hose connection backflow preventer is a high hazard protection valve the contains 2.... | Vent ports |
| A sub atmospheric pressure can also be described as. | A vacuum |
| Why do carbonated beverage machines re require a Backflow Preventer for beverage dispensing equipment? | Because of carbon dioxide gas |
| Where is the #2 test cock of a double check backflow prevention assembly located? | Upstream of check valve #1 |
| What are two types of Cross connections? | Direct and indirect |
| When preforming a field test on a reduced pressure principle backflow assembly, the #2 test cock should be: | Flushed with caution to prevent a premature relief valve discharge. |
| The relief valve on a reduced pressure principle backflow preventer remains closed due to this. | Supply side pressure |
| Where is the best place for the installation of a Backflow Prevention Assembly? | In an easily accessible location in a heated building. |
| To convert 'feet of head" to psi must MULTIPLY by: | .433 |
| What should you do if the air inlet valve of a pressure vacuum breaker assembly will not seat? | Increase supply side pressure |
Created by:
Bmcguire64