Which type of valve is typically used for shutting off flow in plumbing?

The ball valve is commonly used for shutting off flow in plumbing systems because of its straightforward mechanism and reliable performance. This type of valve consists of a spherical disc with a hole through its center, allowing fluid to flow through when the valve is open, and interrupting flow when rotated to a closed position.

Ball valves offer several advantages: they provide an effective seal, are easy to open and close with a simple quarter turn, and are less prone to wear and tear compared to other types of valves. This makes them ideal for applications where quick and reliable shut-off is required, such as in plumbing.

In contrast, a check valve is designed to prevent backflow rather than to shut off the flow. A gate valve, while capable of shutting off flow, is less efficient than a ball valve and requires more turns to operate, which can be cumbersome in situations where rapid shut-off is needed. The pressure relief valve serves a different purpose altogether, as it is used to release excess pressure and protect the plumbing system from damage, rather than controlling flow in the same way that shut-off valves do.