On-off valves are used to start or stop the flow of fluid. These types of valves go by many names, including shutoff, isolation, stop, or block valves. On-off valves are commonly used to start and stop flow in process piping, reroute flow to bypass a piece of equipment or process, or immediately stop flow in an emergency. Most on-off valves are manual valves, but they can be configured with actuators. Also, some valves can be used as either on-off or throttling valves. In this course, we will focus on manual on-off valves.