Which type of valves requires the use of a water hammer arrestor under normal conditions?

Quick-closing valves require the use of a water hammer arrestor under normal conditions due to their design and function. These valves close rapidly, which can create a sudden change in water flow and pressure within the plumbing system, leading to the phenomenon known as water hammer. Water hammer is characterized by a loud banging sound when the flow of water is abruptly stopped, and it can cause significant damage to pipes, fittings, and fixtures over time.

In order to mitigate the effects of water hammer, the installation of a water hammer arrestor is recommended. This device serves as a cushion of air that absorbs the shock created by the sudden stop in water flow, thus protecting the plumbing infrastructure from potential damage. Properly installed water hammer arrestors can effectively prevent the adverse effects associated with the quick closure of valves and ensure a more stable and safe plumbing system.