What type of valve is typically used for isolation purposes in piping systems?

A gate valve is commonly used for isolation purposes in piping systems because it provides a full, unobstructed flow path when fully opened, allowing for minimal resistance to the fluid. When closed, it creates a tight seal, which effectively prevents any flow through the valve. This makes it ideal for applications where the complete shut-off of flow is needed.

Additionally, gate valves are generally easier to operate and maintain for on/off service compared to other types of valves, as they require less torque to open and close. They are best suited for applications that do not require frequent cycling, as consistent operation can wear out the seat and reduce effectiveness over time.

While other valves serve important functions, they may not be as effective for isolation. For instance, ball and butterfly valves can also be used for isolation but may not provide the same level of tight seal and fluid dynamics as a gate valve in certain applications. A check valve is designed primarily to prevent backflow rather than for isolation, making it unsuitable for this specific purpose.