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 PSI
100 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

• Friction loss tables
  List of printable friction loss tables for all common hose sizes
  • 1 3/4" Friction Loss Printout
  • 2 1/2" Friction Loss Printout
• Friction loss cheat sheet
  Compact friction loss table for hose sizes & gpm combo. Limited to 100' increments & larger jumps between gpm.
• Friction loss formula Math formula to solve friction loss. Effective, but more time consuming & error prone.
• Instructions on calculating pump discharge pressure
  Learn pump pressure management combining elevation change, hose friction loss & appliance friction loss.
• Pump and plumbing diagram
  Visual tool to map a fire engine's pump and plumbing. Follow the water to learn how the pump, valves and plumbig work together to deliver water to the fire.

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