Centrifugal Pump Capacities in combinated fire systems

Discussion created by gustavocanizzo on Aug 20, 2019
Latest reply on Aug 22, 2019 by bobs47

Hi everyone,
I am designing a system that has automatic sprinklers, deluge system, hoses and hydrants.
Once I finish the hydraulic calculation of the systems working together, when I try to select the pump system, in NFPA 20 (2016) 4.9.1 it sais:

"A centrifugal fire pump for fire protection shall be selected so that the greatest single demand for any fire protection system connected to the pump is less than or equal to 150 percent of the rated capacity (flow) of the pump"

Do I have to take the 150 percent of all of systems working simultaneusly or "greatest single demand" refer to one of them (ex. deluge system)? when I select the power demand of pump motor.
The point is that, maybe, the 150 percent of deluge system flow is bigger than the 100 percent of all of systems flow working together, and in that case I could select a cheaper pump.