Question

A device installed in a drainage system to prevent reverse flow is a?

1) Check valve
2) Pressure relief valve
3) Backflow preventer
4) Overflow pipe

Answer 1

A device installed in a drainage system to prevent reverse flow is a Backflow preventer. It ensures unidirectional flow and protects against possible contamination by not allowing water to reverse back into the clean water supply. Option 3.

Step-by-step explanation:

The device installed in a drainage system to prevent reverse flow is a Backflow preventer. This device is crucial for maintaining a unidirectional flow of water, ensuring that potentially contaminated water does not re-enter the clean water supply. Among the options given, a check valve is also designed to allow flow in only one direction, but it is not the same as a backflow preventer, which is more comprehensive in its function for preventing reverse flow in various situations. A pressure relief valve protects against overpressure but does not prevent reverse flow.

An overflow pipe prevents flooding by directing excess water away, but it doesn't prevent backflow. The backflow preventer's design typically includes a series of mechanical check valves or an air gap that acts as a barrier to flow reversals, thus improving the flow rate and ensuring that the water in sink drains or other points of use remains safe from contamination.