What is the purpose of a water-hammer arrestor?

The primary purpose of a water-hammer arrestor is to absorb pressure surges that occur in a plumbing system. When water flowing through pipes is suddenly stopped by a valve closure, it can create a shock wave known as water hammer. This can lead to loud banging noises and potentially damage the plumbing system.

Water-hammer arrestors are equipped with a cushion of air or gas that compresses to absorb this shock wave. This cushioning effect helps to prevent the abrupt pressure changes that can result in noise and pipe stress, ultimately contributing to the longevity and reliability of the plumbing system.

The other options do not relate to the function of a water-hammer arrestor. Increasing water temperature pertains to heating devices, filtering impurities relates to water filtration systems, and measuring water flow rate is the function of flow meters. Each of these devices serves a distinct purpose unrelated to the management of pressure surges in plumbing systems.