When fully opened, which valve will have the highest head loss?

The globe valve, when fully opened, will have the highest head loss compared to the other types of valves listed. This is primarily due to the design of the globe valve, which features a globe-shaped body that provides a more significant change in direction for the flow of water. This change in direction and the longer flow path within the valve creates resistance, leading to higher head loss.

In terms of flow dynamics, the globe valve restricts flow more than other types of valves, even when fully opened. The internal passageway is not as streamlined, causing turbulence as the water moves through. This characteristic results in a higher velocity drop across the valve and, consequently, a greater head loss.

While the other valves—such as the gate, plug, and ball valves—are designed to provide less resistance to flow when fully opened, they feature straighter flow paths and are thus more efficient for minimizing head loss in a water distribution system.