Two widely used pump types in the fire service include Positive Displacement Pump and which other pump?

• A. Centrifugal pump
• B. Rotary pump
• C. Gear pump
• D. Piston pump

Answer: (A)

Water pumps in firefighting fall into two broad families: positive displacement pumps and centrifugal pumps. Positive displacement pumps move a fixed amount of water with each cycle, so their pressure rises quickly when the discharge is restricted, giving high pressure at relatively low flow. Centrifugal pumps use an impeller to impart velocity to the water and then convert that energy into pressure, delivering large volumes at moderate pressures. Because these two families cover different operating needs—high pressure with limited flow versus high flow with moderate pressure—the centrifugal pump is the other widely used pump type alongside positive displacement pumps in fire service practice. The other options are various positive displacement pump types, not a separate major category.