Centrifugal fire pumps may make use of:

Centrifugal fire pumps are designed to move water by converting rotational energy into hydrodynamic energy, creating flow through the pump. They operate based on the principles of centrifugal force, which requires a certain level of pressure to effectively draw in water and push it through the system.

Positive intake pressures are crucial for centrifugal pumps because these systems rely on the creation of a pressure differential between the pump inlet and outlet to function efficiently. When a centrifugal pump draws water, it needs to maintain a positive pressure at the inlet to prevent cavitation, which occurs if the pressure drops too low, leading to the formation of vapor bubbles that can damage the pump impeller and reduce its effectiveness.

The other options do not align with how centrifugal pumps are meant to operate. For instance, relying on negative pressure or vacuum pressure would create conditions that are not optimal for performance and could lead to issues such as cavitation. Atmospheric pressure is a baseline condition for many systems but does not provide the necessary force for the pump to perform effectively when pressurizing water for fire suppression. Thus, utilizing positive intake pressures is essential for the reliable and effective operation of centrifugal fire pumps.