Red Seal Steamfitter/Pipefitter Practice Exam

Which type of valve is typically used for quick shut-off in a plumbing system?

1. Gate valve

2. Ball valve

3. Check valve

4. Globe valve

The correct answer is: Ball valve

The ball valve is typically used for quick shut-off in a plumbing system due to its operational design. When the lever on a ball valve is turned 90 degrees, the ball inside rotates to either allow or block the flow of fluid. This mechanism enables the valve to shut off the flow almost instantaneously, making it highly efficient for applications where rapid on/off control is necessary. On the other hand, gate valves, while effective for fully open or closed positions, are not designed to provide quick shut-off; their operation involves moving a gate into the flow path, which requires more time and is not suited for frequent use. Check valves automatically allow fluid to flow in only one direction, serving a different purpose that doesn't involve manual control for shut-off. Globe valves are primarily used for throttling and control, taking more time to open or close due to their design, which involves a globular body shape that restricts flow paths. Therefore, for scenarios demanding quick response in stopping or starting flow, the ball valve is the preferred choice.