What is the primary operational disadvantage of using a piston positive displacement pump?

The primary operational disadvantage of using a piston positive displacement pump is the pulsation in the fire stream. This pulsation occurs because the pump displaces a fixed volume of fluid with each stroke, leading to a stop-and-start motion that results in fluctuations in pressure and flow rate. In firefighting applications, a steady and consistent flow is crucial for effective operation. The presence of pulsation can affect the ability to apply water accurately and steadily, thereby diminishing the effectiveness of the firefighting efforts.

While maintenance costs can be a concern with any pump, they are not uniquely high for piston pumps compared to other types. Additionally, while piston pumps do exhibit variable efficiency with changes in flow rate, this is characteristic of many pump types and not a unique operational disadvantage. Concerns about the incompatibility with foam solutions typically relate more to specific formulations rather than the operational principles of piston pumps themselves. Therefore, the pulsation in the fire stream stands out as the most significant operational drawback when using a piston positive displacement pump.