What is a Shutoff Valve?
A valve designed for and capable of positive closure to prevent flow within a piping system.
Typical shutoff valves include, but are not limited to, manually-actuated, power-actuated, or spring-actuated fail-safe shutoff valves.
Usually excluded are self-actuated valves, such as check valves, pressure regulators, flow controllers, and other devices that are not intended to provide positive shutoff for safety isolation. [SEMI F1-90]
