When supplying an elevated master stream, what is the pump discharge pressure if one 5-inch line is used at a distance of 200 feet to the ladder truck raised 80 feet?

To determine the correct pump discharge pressure when supplying an elevated master stream, it's essential to consider both the vertical and horizontal distances involved as well as the necessary friction loss due to the water's movement through the hose.

When supplying an elevated master stream to a ladder truck, you must first account for the height the water must be lifted, which is the elevation of the ladder—in this case, 80 feet. The rule of thumb in firefighting hydraulics is that for every 1 foot of elevation, you must add approximately 5 psi to the pump pressure. Therefore, for an elevation of 80 feet, you would calculate:

80 feet x 5 psi/foot = 400 psi.

Next, you need to consider the friction loss occurring over the distance the water is traveling through the hose. With a 5-inch hose, the friction loss per 100 feet of hose is typically around 0.8 psi. Since the line is 200 feet long, the friction loss would be calculated as:

(200 feet / 100) x 0.8 psi = 1.6 psi.

Now, adding these values together gives us:

400 psi (elevation) + 1.6 psi (friction loss) =