What type of valve is typically used for shut-off in plumbing systems?

A ball valve is typically used for shut-off in plumbing systems because it provides a reliable and effective way to stop the flow of water with minimal resistance when fully closed. The design of a ball valve features a hollow, perforated sphere, or "ball," that rotates within the valve body. When the handle is turned to align the ball's opening with the flow path, water can easily pass through. Conversely, turning the handle to close the valve positions the solid part of the ball against the flow, effectively blocking it.

Ball valves are appreciated for their durability and ability to create a tight seal when closed, making them ideal for on/off service. They can be operated quickly and provide minimal pressure drop across the valve when open. This efficiency and functionality make them a common choice for shut-off applications in residential and commercial plumbing systems.

Other types of valves, such as check valves or pressure relief valves, serve specific purposes. Check valves prevent backflow and maintain one-directional flow; pressure relief valves are designed to release excess pressure to protect the system. Gate valves, while also used for shut-off, require a full turn to open or close and can become less effective over time due to wear or debris, which can hinder their operation.