🔍 Key Concepts

• Butterfly valve operation – how the internal disc moves in relation to the piping and flow • Handle position vs. disc position – how the handle indicates whether the valve is open or closed • Standard convention for indicating valve open/closed on manual quarter‑turn valves

💭 Think About

• Visualize the disc inside the pipe: when flow is fully open, how is the disc aligned with the flow? When closed, how is it aligned? • Think about how an operator, walking by quickly, can tell at a glance whether the valve is open or closed based on the handle position. • Compare these answer choices to what you know about levers on ball valves and gate valves—what’s the usual relationship between lever direction and flow direction?

✅ Before You Answer

• Make sure you know which position of the disc corresponds to minimum resistance to flow (fully open). • Confirm which handle orientation gives a clear, unambiguous indication of open vs. closed at a glance. • Verify that the choice you pick would be consistent for all flow rates, not just partial opening.