Which of the following does NOT influence pump calculations?

The correct understanding revolves around the factors that commonly influence pump calculations in firefighting operations. Pump type is typically not a variable that directly affects the calculations made for pump performance in specific scenarios. Instead, it is the characteristics of the other options that come into play when making these calculations.

Hose length is crucial because it directly affects friction loss and the overall pressure needed to maintain flow at the nozzle. Flow rate determines the amount of water being delivered and impacts the calculations related to hydraulic pressure. Nozzle size affects the discharge velocity and pressure at the nozzle, which influences the necessary pump pressure to achieve the desired flow rate.

In contrast, while pump type can indicate certain performance metrics or efficiencies, it does not inherently change the calculations for pressure, flow, and friction loss during operations. Therefore, focusing on hydraulic principles and operational considerations, the type of pump itself does not play a direct role in the calculation process, making it the correct answer for what does NOT influence pump calculations.