What type of fire pump does not require a water prime?

The correct answer is the type of fire pump that does not require a water prime is a positive displacement pump. These pumps operate by trapping a fixed volume of fluid and forcing it into the discharge pipe. This method of operation means that they can handle both liquid and air efficiently without needing to be primed with water beforehand.

In contrast, centrifugal pumps, like horizontal centrifugal and vertical turbine pumps, rely on a consistent supply of water to create the necessary suction for operation. These pumps must be primed, which means they require the pump casing and suction line to be filled with water before they can effectively move fluid.

Submersible pumps are designed to operate submerged in the fluid they are pumping. While they may not require priming in the same way as centrifugal pumps since they are already submerged, they also differ significantly from positive displacement pumps in their operation.

Understanding these distinctions in pump types is crucial in fire protection systems, where reliable water supply and efficient operation are paramount.