A butterfly valve is a quarter‑turn valve operated by a handle, gearbox or actuator. You can check its open‑closed status simply from the position of the handle or indicator.

  When open: The handle or position indicator is “parallel to the pipeline”. This means the internal disc is turned 90° and aligned with the flow direction.

  When closed: The handle or indicator is “perpendicular to the pipeline ”. This means the disc blocks the pipe completely.

  Because most butterfly valves have clear position marks on the actuator, you can also read the scale directly to confirm whether it is fully open, fully closed or partially open.