At what GPM flow would the MPO need to add friction loss in an appliance?

Adding friction loss in an appliance is necessary when the flow rate reaches certain thresholds that can significantly impact the efficiency and performance of the firefighting system. The specific flow rate at which this adjustment is needed is typically based on standard practices in the fire service.

In this case, the correct answer indicates that the Mobile Pump Operator (MPO) should consider friction loss starting at a flow rate of 350 GPM. This threshold is established because below this flow rate, the friction loss in hoses and appliances may not substantially affect the overall pressure and flow dynamics within the system. However, at 350 GPM and above, the increased flow can lead to a noticeable increase in friction loss that must be taken into account to ensure adequate pressure reaches the nozzle.

In practical terms, when operating at or above this flow rate, an MPO must be mindful of the additional friction loss that will occur from hoses, fittings, and any appliances in use, as this can influence operational strategy and resource allocation during firefighting efforts. Understanding when to account for friction loss helps maintain effective fire suppression and ensures firefighters have the necessary water flow for effective operations.