What phenomenon is caused by the suddenly stopping of water moving through a hose or pipe?

The phenomenon that occurs when water moving through a hose or pipe suddenly stops is known as water hammer. This occurs due to the inertia of the moving water. When the flow of water is abruptly halted, such as when a valve is closed quickly, the momentum of the water creates a pressure surge that travels back through the pipe. This pressure wave can result in a banging or knocking sound, and in some cases, can cause damage to the piping system if the pressure surge is strong enough.

Understanding water hammer is critical for firefighting and plumbing as it can affect the integrity of the system and lead to leaks or bursts if not managed properly. This phenomenon is distinct from static pressure, which is the pressure of fluid at rest, or dynamic surge, which refers to changes in pressure due to variations in water flow rates. Fluid shock is a less commonly used term and does not generally describe the sudden pressure changes associated with water hammer as accurately. Thus, recognizing water hammer is essential in managing and maintaining effective water delivery systems in fire service operations.