What is a main factor that influences a centrifugal fire pump's discharge pressure?

The main factor influencing a centrifugal fire pump's discharge pressure is the pressure of the water when it enters the pump from a pressurized source. This is because centrifugal pumps rely on the difference in pressure between the water entering the pump and the water being discharged. When the inflow pressure is higher, it assists in generating greater discharge pressure as the centrifugal force propels the water through the impellers.

This principle is crucial for understanding how centrifugal pumps operate in fire service applications. The pressure at the pump's inlet is essential as it determines the pump's ability to push water through the system. If the inlet pressure is low, the discharge pressure will generally be lower as well, regardless of other factors such as impeller design or hose length.

While the diameter of pump impellers and their design can affect pump efficiency and flow rate, they do not directly influence the discharge pressure as significantly as the pressure of the incoming water. Similarly, the length of the discharge hose can lead to friction loss, which can reduce the effective pressure at the discharge point but is not a primary factor in determining the pump's overall discharge pressure at the source. Water temperature can impact viscosity and pump performance, but it is not as significant a factor in discharge pressure as the inlet pressure from