What is the approximate engine pump pressure needed to deliver 600 gpm through a fog nozzle on a deck gun with three 2-1/2" lines?

To determine the approximate engine pump pressure needed to deliver 600 gallons per minute (gpm) through a fog nozzle on a deck gun with three 2-1/2" lines, hydraulic calculations are necessary.

When delivering water through a fog nozzle, pressure loss is incurred due to the diameter of the lines, the flow rate, and the characteristics of the nozzle itself. A common formula used in fire service hydraulics considers friction loss due to the hoses and the nozzle pressure required for adequate operation.

For a deck gun operating at 600 gpm, you would typically have a nozzle pressure requirement that varies based on the type of nozzle. For a typical fog nozzle, the nozzle pressure is often around 100 psi. Additionally, you must account for friction loss in the hoses. Each 2-1/2" line has a certain friction loss per 100 feet, which, at 600 gpm, can significantly contribute to the total pressure required at the pump.

Using standard calculations, friction loss can be determined using various fire hose friction loss formulas. For instance, if you consider the friction loss for 100 feet of 2-1/2" hose at 600 gpm, it can sum to approximately 25 to