Backflow Prevention Practice Exam

A water system pressure of 10 psi (69 kPa) and a plumbing system pressure of 20 psi (138 kPa) may be described as _____?

1. Backpressure

2. Backsiphonage

3. Gauge pressure differential

4. Static condition

The correct answer is: Backpressure

The situation described involves two different pressures: the pressure of the water system and the pressure of the plumbing system. When the plumbing system pressure (20 psi) is higher than the water system pressure (10 psi), it creates a scenario where there is a pressure differential. This condition can lead to what is known as backpressure. Backpressure occurs when the pressure in the plumbing system exceeds that of the supply system, which can force water to flow backwards from the plumbing system into the supply system. Understanding this is crucial in identifying potential backflow conditions that can threaten water quality. In this case, the higher plumbing system pressure could push contaminants back into the water supply if proper backflow prevention measures are not in place. In contrast, backsiphonage would occur when the pressure in the plumbing system falls significantly below that of the water supply, allowing the water to flow back into the plumbing system, typically due to a vacuum or negative pressure. Gauge pressure differential refers to the measurement of pressure in relation to atmospheric pressure, while a static condition would imply no movement or change in pressure, neither of which accurately describe the scenario of higher plumbing pressure forcing water backwards.