When drafting, as lift or friction loss in hard intake hose is increased, the water supply capability of the pump:

When drafting, the performance of the pump relies heavily on the relationship between lift or friction loss and the water supply capability. As lift or friction loss in hard intake hose increases, the system faces increased resistance to the flow of water into the pump. This additional resistance makes it more difficult for the pump to draw water, effectively reducing the volume of water that the pump can supply.

In a drafting scenario, any increase in lift (the vertical distance water has to be lifted) or friction loss (the energy lost due to friction within the hose) results in a lowering of the net positive suction head (NPSH) available to the pump. This negative impact leads to a decrease in the water supply capability of the pump because the pump is less able to maintain the necessary flow against these losses. Therefore, understanding this relationship is critical for effective operation of fire pumps and ensuring adequate water delivery in emergency situations.