Which type of valve shows whether it is open or closed?

The correct answer is an indicating valve because it is specifically designed to provide a visual indication of its open or closed status. This feature is essential in fire protection systems, as those working on or inspecting the system need to quickly ascertain whether a valve is in the proper position. Indicating valves are often equipped with a handle or some form of indicator that clearly shows the valve’s status, facilitating easier operation and maintenance.

Pressure relief valves, check valves, and butterfly valves do not typically offer this direct visual indication. A pressure relief valve functions to release excessive pressure but does not indicate its position in terms of closed or open. Check valves are designed to allow flow in one direction and automatically close to prevent backflow, and they do not indicate whether they are functioning correctly. Butterfly valves can be operated to control flow but may not have the built-in feature to visibly show their status without additional components or indicators. Therefore, the distinguishing characteristic of an indicating valve makes it the best choice for demonstrating open or closed status.