A pumping system utilizing a centrifugal pump is designed for a specific discharge head in feet. What happens to the pump's discharge pressure when the Specific Gravity (SG) of the fluid pumped changes?

Correct Answer: Option B — Lower SG fluids will cause the discharge pressure to decline.

Centrifugal pump discharge pressure is directly proportional to the fluid's density. Since pressure head in feet remains constant for a given impeller speed, the actual discharge pressure in PSI will decline if the specific gravity of the pumped fluid decreases, as the pump imparts less force per unit volume.