What typically causes water hammer in a distribution system?

Water hammer is commonly caused by sudden changes in water flow, particularly from the quick closure of valves. When a valve closes swiftly, the momentum of the moving water creates a high-pressure wave that travels back through the piping system. This pressure wave can result in a loud banging noise, which is characteristic of water hammer, and can potentially lead to damage in the pipes and fittings due to the increased pressure exerted.

Understanding the dynamics of fluid flow is essential here; when water is suddenly stopped, the kinetic energy of the moving water must be dissipated, often resulting in vibrations and pressure surges known as water hammer. This phenomenon can be exacerbated in systems where flow rates are high or valves are operated rapidly.

The other choices do not directly contribute to the occurrence of water hammer. For example, gradual increases in temperature, excessive water pressure, and corrosion of pipes could impact overall system performance or integrity, but they are not the primary triggers for the rapid pressure changes that define water hammer.