Backflow Prevention Practice Exam

The presence of air in a piping system generally serves what purpose?

1. To prevent backflow

2. To aid in flow control

3. To absorb water hammer

4. To decrease pressure

The correct answer is: To absorb water hammer

The presence of air in a piping system primarily serves the purpose of absorbing water hammer. Water hammer occurs when there is a sudden change in the velocity of water, such as when a valve closes quickly, creating pressure waves that travel through the pipes. These pressure waves can cause loud banging noises and potentially damage the piping system. By incorporating air into the system, it acts as a cushion that absorbs these pressure changes, minimizing the impact of water hammer and promoting system stability. While other choices might seem relevant, they address different aspects of a piping system. Preventing backflow typically involves specific devices designed to create a physical barrier against reverse flow, while aiding in flow control often relates to the design of valves and fittings rather than air itself. Decreasing pressure is not a primary role of air in the system; rather, pressure management involves other engineering solutions.