What percentage of rated capacity must the pumping system deliver at 200 psi net pump pressure?

• A. 100 percent
• B. 70 percent
• C. 50 percent
• D. 80 percent

Answer: (B)

In pump performance testing, you look at how the pump behaves when you push it to a high net pressure. The idea is to confirm the pump can still deliver a substantial portion of its rated capacity even as pressure climbs. The requirement at 200 psi net pump pressure is that the pumping system must deliver 70 percent of its rated capacity. This ensures there’s enough flow available to support firefighting operations when nozzle pressures and friction losses are high.

The rated capacity is the pump’s intended flow under standard test conditions, and the 200 psi net pump pressure represents a demanding condition where flow naturally decreases from its maximum. Requiring 70% provides a practical safety margin: the pump remains capable of supplying multiple outlets or maintaining essential flow while meeting the elevated pressure demand.