What is the desired pump pressure when supplying two lines of 2-1/2" hose, one 200 feet long and one 300 feet long, each with a 250 gpm nozzle operating at 100 psi?

To determine the desired pump pressure when supplying two lines of 2-1/2" hose, you must account for the nozzle pressure, the friction loss in the hoses, and any elevation changes if applicable.

Each nozzle operates at 100 psi. Therefore, the nozzle pressure is set at 100 psi. Next, you must calculate the friction loss in the hoses. The friction loss for a 2-1/2" hose is approximately 2 psi per 100 feet at 250 gpm.

For the first line (200 feet long):

• Friction loss = 2 psi/100 feet × 200 feet = 4 psi

For the second line (300 feet long):

• Friction loss = 2 psi/100 feet × 300 feet = 6 psi

Next, you add the friction losses together:

• Total friction loss = 4 psi + 6 psi = 10 psi

Finally, to determine the desired pump pressure, you add the total friction loss to the nozzle pressure:

• Desired pump pressure = Nozzle pressure + Total friction loss

• Desired pump pressure = 100 psi + 10 psi = 110 psi

However, the calculations for desired pump pressure factor in additional safety