4 Inch Hose  Friction Loss Table
This chart is designed (using the friction loss formula) to find quick and accurate answers for 4" fire hose friciton loss. To find the friction loss for a 100 foot section of fire hose, find the column with the desired GPM and to its right you'll see the corrosponding friction loss. You can also print this image on a 8.5x11 sheet of paper.
Example: Friction loss for 100 ft of 4" fire hose with 1,000 GPM is 20 psi. You can find the corrosponding friction loss for 1,000 gpm at the bottom of column 4 in the chart below. You can see that 1,000 gpm has 20 psi friction loss. You can also see the answer on the friction loss calculator
Friction Loss Explained
Friction loss occurs when water passes through a hose. Hose length, diameter, and GPM (volume) all affect friction loss. As water passes through a hose, friction between the water and the inside surface of the hose causes turbulence, which slows the water. The results in a PSI drop (pressure loss) at the other end of the hose. The higher the gpm passing through a hose, the more turbulance and friction loss will result.
Friction loss examples:
100 ft 1" @ 100 gpm = 150 PSI100 ft 1 1/2" @ 100 gpm = 24 PSI
100 ft 1 3/4" @ 150 gpm = 34.88 PSI
200 ft 1 3/4" @ 150 gpm = 69.75 PSI
100 ft 1 3/4" @ 185 gpm = 53.05 PSI
200 ft 1 3/4" @ 185 gpm = 106.1 PSI
100 ft 1 3/4" @ 200 gpm = 62 PSI
200 ft 1 3/4" @ 200 gpm = 124 PSI
100 ft 2 1/2" @ 150 gpm = 4.5 PSI
100 ft 2 1/2" @ 200 gpm = 8 PSI
100 ft 2 1/2" @ 300 gpm = 18 PSI
200 ft 2 1/2" @ 300 gpm = 36 PSI
Fire Engine Operator Tools

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