On a pump curve, which axis represents capacity?

On a pump curve, which axis represents capacity?

• A. Vertical axis
• B. Horizontal axis
• C. Diagonal axis
• D. Both axes

Answer: (B)

Capacity, which is the flow rate, is plotted on the horizontal axis of a pump curve. The vertical axis shows head (feet of head or pressure). This layout lets you read the flow value along the x-axis and the corresponding head on the y-axis, and to find the operating point you look where the pump curve meets the system curve. There isn’t a diagonal axis used, and capacity isn’t represented on both axes. So the axis for capacity is the horizontal axis.

Capacity, which is the flow rate, is plotted on the horizontal axis of a pump curve. The vertical axis shows head (feet of head or pressure). This layout lets you read the flow value along the x-axis and the corresponding head on the y-axis, and to find the operating point you look where the pump curve meets the system curve. There isn’t a diagonal axis used, and capacity isn’t represented on both axes. So the axis for capacity is the horizontal axis.