What pressure is needed to achieve a flow rate of 185 GPM with a 1 ¾" 200' Pre-Connect and a 15/16" SB nozzle?

To determine the pressure needed to achieve a flow rate of 185 gallons per minute (GPM) with a 1 ¾ inch pre-connect and a 15/16 inch smooth bore (SB) nozzle, we can use a flow formula that considers nozzle flow, friction loss due to hose length, and the elevation gain if applicable.

The formula typically includes two primary factors: the nozzle pressure needed to achieve the desired flow rate and the friction loss incurred over the length of the hose. For a 15/16 inch SB nozzle, flow rates can be approximated based on established charts or formulas, indicating a required nozzle pressure around 50 psi to achieve 185 GPM.

Next, friction loss in the hose must be calculated. For a 1 ¾ inch hose, the friction loss is usually around 20 psi for the first 100 feet (and can vary depending on the specifics of the hose). Thus, for a 200 feet length, it would be approximately 40 psi.

Adding these two components—50 psi (nozzle pressure) and 40 psi (friction loss)—leads to a total of about 90 psi. This matches closely with the choice of 90 psi. However, for optimal operation and