The amount of work that a pump must do to produce a fire stream is called the ______ pressure.

• A. Pump discharge
• B. Residual
• C. Maximum net
• D. Maximum discharge

Answer: (A)

The pressure a pump must generate on its discharge side to push water to the nozzle is what determines the fire stream’s strength. This is called the pump discharge pressure. It represents the actual hydraulic pressure the pump delivers to overcome hose and nozzle losses, elevation, and any other friction in the system. In practice, you plan the discharge pressure by adding the desired nozzle pressure to all losses along the line (friction in the hose, fittings, elevation changes, etc.). So, if you need a certain nozzle pressure to achieve the intended spray and you’re facing friction losses plus lift, the pump discharge pressure equals those together. Residual pressure refers to the pressure remaining somewhere in the system after losses are accounted for, not the pump’s output, and the other terms aren’t used for this concept.