All of the following can cause water hammer except:

Water hammer is a phenomenon that occurs when a fluid in motion is suddenly forced to stop or change direction. This sudden change creates a pressure surge or wave within the piping system, which can cause loud banging noises and potential damage to the plumbing infrastructure.

The layout of the pipes typically does not contribute to water hammer directly. While certain configurations or installations might exacerbate the problem, they don't inherently cause the issue. Instead, the causes of water hammer are more directly associated with dynamic changes in water flow.

Rapid valve closure causes the water flow to stop abruptly, resulting in pressure surges. High water pressure can amplify the effects of water hammer because the energy within the system is greater, leading to more forceful pressure waves. Air in the pipes can also contribute by creating a compressible gas that may lead to fluctuations in pressure when the water flow changes and consequently allows for transient pressures to develop.

Thus, the layout of the pipes is not a direct cause of water hammer, making it the correct answer to the question.