To determine the correct pressure required to deliver 175 GPM (gallons per minute) through 200 feet of 1.88-inch hose with a fog nozzle, it’s important to consider both the friction loss in the hose and the nozzle pressure.
Using the appropriate formulas, you can calculate the friction loss for the specific diameter of the hose and the flow rate. Typically, for a 1.88-inch diameter hose, the friction loss at 175 GPM is approximately 5 to 6 psi per 100 feet. Therefore, at 200 feet, the total friction loss would be around 10 to 12 psi.
Additionally, fog nozzles generally require a residual pressure to maintain effective water delivery, often recommending around 100 psi at the nozzle itself. When you add the friction loss in the hose to the pressure needed at the nozzle, you arrive at the total pressure needed to ensure proper flow.
In this scenario, if we estimate the friction loss to be around 12 psi for the 200 feet of hose and we want to maintain an effective nozzle pressure of about 100 psi, this results in a total required pump discharge pressure of approximately 112 psi.
However, considering operational variables and safety margins,