Your officer just pulled 250 feet of 2 1/2 static line with a 1 1/8 tip smooth bore nozzle. What is your pump discharge pressure?

To determine the pump discharge pressure when using a 2 1/2 inch static line with a 1 1/8 inch tip smooth bore nozzle, we must consider several factors including the nozzle's flow and friction loss associated with the length of hose being used.

First, a 1 1/8 tip often has a flow of approximately 250 gallons per minute (GPM). To calculate the pressure needed to achieve this flow rate, it is essential to apply the formula for nozzle pressure, which combines the flow and friction losses.

The standard formula for calculating the nozzle pressure (NP) is:

NP = 0.5 x (GPM)^2 / (Diameter in inches)^2 + FL

Where FL represents the friction loss. For a 2 1/2 inch line, we can estimate the friction loss over 250 feet using common tables or formulas (such as the friction loss formula: FL = C x L x (GPM/100)^2, where C is the coefficient for the specific diameter of hose).

Typically, for a 2 1/2 inch line, the friction loss is approximately 10 PSI per 100 feet for a flow rate of 250 GPM. Therefore, for