A self-regulating fire pump unit which can be controlled to operate under required conditions for sourcing a fire protection system such as sprinklers. The fire pump unit can be operated in accordance with a control curve based on detected pressure and flow. The control curve can include: a) a first setpoint of rated total value of the system load for the pressure and the flow, b) a second setpoint of a minimum partial percentage of the rated total value of the pressure at an over-percentage of the rated total value of the flow, c) a path which maintains the rated total value of the pressure for all values of the flow up to the first setpoint, d) a path between the first setpoint and the second setpoint, e) a path from the second setpoint which limits values of the pressure for values of the flow greater than the second setpoint.