Which valve would cause the highest restriction to flow?

• A. Globe Valve
• B. Stop and Waste Valve
• C. Ball Valve
• D. Gate Valve

Answer: (B)

Understanding how valve design affects flow helps you pick the right valve for pressure and flow control. When a valve is fully open, the size of the bore and the straightness of the flow path determine how little resistance the water faces. Ball valves and gate valves are designed to offer a straight, unobstructed path when open, so they provide the lowest resistance.

Glove-like globe valves, while excellent for throttling and control, still introduce some obstruction from the seated disk and the way the flow must pass around it, which means more resistance than a ball or gate valve even when wide open.

A stop-and-waste valve combines a shutoff mechanism with a waste (drain) port. That extra drain path adds an additional restriction in the flow path, and the overall path through the valve isn’t as straight or roomy as a full-bore ball or gate valve. Because of that added limitation from the waste port, it tends to create the greatest resistance to flow among these options.

So, the valve with the highest restriction to flow is the stop-and-waste valve due to its additional drain passage layered onto the shutoff geometry.