Unit 5. Backflow Prevention - Test Your Knowledge
questions with accurate answers
Briefly describe the reduced pressure-principle backflow preventer.
Ans✓✓✓ It is located upstream of the point of injection. It is also called
a reduced-pressure backflow assembly (RPBA) or a reduced-pressure
zone valve (RPZ). This device consists of two spring-loaded check
valves. They have an atmospheric port between them. Whenever
pressure drops at one of the valves, the port opens and water drains out.
In this way, the check valves prevent backflow, and the atmospheric port
prevents backsiphonage. The reduced pressure-principle backflow
preventer is required if your irrigation system connects to a domestic or
municipal water supply.
Define "backpressure" and name some common causes. Ans✓✓✓ A
difference in pressure when a supply line is connected to a high-pressure
system. If the system exceeds the operating pressure of the supply pipes,
backpressure can result. Common causes are:
1. Booster pumps.
2. Connections to boilers.
3. Cross connections with another system running at a higher pressure.
, 4. Elevated piping.
Define "backsiphonage" and name some common causes. Ans✓✓✓ A
vacuum caused by reduced pressure in a supply line to a piping system.
This vacuum causes a siphoning action. Common causes are:
1. High liquid velocity in pipelines.
2. A line break or repair that is lower than a service point.
3. Lowered main pressure due to a high rate of water withdrawal (ex.
fire fighting).
4. Reduced supply pressure on the suction side of the booster pump.
Define and briefly explain "backflow." Ans✓✓✓ The movement of a
liquid in reverse of the normal direction of flow in a piping system.
Backflow can also occur in the injection line, causing the pesticide tank
questions with accurate answers
Briefly describe the reduced pressure-principle backflow preventer.
Ans✓✓✓ It is located upstream of the point of injection. It is also called
a reduced-pressure backflow assembly (RPBA) or a reduced-pressure
zone valve (RPZ). This device consists of two spring-loaded check
valves. They have an atmospheric port between them. Whenever
pressure drops at one of the valves, the port opens and water drains out.
In this way, the check valves prevent backflow, and the atmospheric port
prevents backsiphonage. The reduced pressure-principle backflow
preventer is required if your irrigation system connects to a domestic or
municipal water supply.
Define "backpressure" and name some common causes. Ans✓✓✓ A
difference in pressure when a supply line is connected to a high-pressure
system. If the system exceeds the operating pressure of the supply pipes,
backpressure can result. Common causes are:
1. Booster pumps.
2. Connections to boilers.
3. Cross connections with another system running at a higher pressure.
, 4. Elevated piping.
Define "backsiphonage" and name some common causes. Ans✓✓✓ A
vacuum caused by reduced pressure in a supply line to a piping system.
This vacuum causes a siphoning action. Common causes are:
1. High liquid velocity in pipelines.
2. A line break or repair that is lower than a service point.
3. Lowered main pressure due to a high rate of water withdrawal (ex.
fire fighting).
4. Reduced supply pressure on the suction side of the booster pump.
Define and briefly explain "backflow." Ans✓✓✓ The movement of a
liquid in reverse of the normal direction of flow in a piping system.
Backflow can also occur in the injection line, causing the pesticide tank
