Learn how to solve friction loss (fire hose pressure loss) with the friction loss formula. See simple examples of solving friction loss formula. Use a scientific calculator, a standar calculator or even solve the equation by hand. Use the online Friction Loss Calculator to verify your answer(s).
FL = C * (Q / 100) ^2 * L / 100What is the friction loss for a 200 foot of 1.75 inch hose flowing 150 GPM of water?
Coefficient (C) for 1.75" hose is 15.5 (See Table 1)Answer: There's 69.75 PSI friction loss for a 200 foot of 1.75
inch hose with 150 GPM.
Answer verified in the friction loss calculator
Table 1 Friction Loss Coefficient 

Hose Diameter  Coefficient 
0.75 inch  1100 
1 inch  150 
1 ¼ inch  80 
1 ½ inch  24 
1 ¾ inch  15.5 
2 inch  8 
2 ½ inch  2 
3 inch  0.677 
3 ½ inch  0.34 
4 inch  0.2 
4 ½ inch  0.1 
5 inch  0.08 
6 inch  0.05 
What is the friction loss of 200 feet of 1.75" hose with 200 gpm? Answer 200' of 1.75" @ 200 GPM
What is the friction loss of 150 feet of 2" hose with 500 gpm? Answer 150' of 2" @ 500 GPM
What is the frictin loss of 100' of 1" hose with 100 gpm?Answer 100' of 1" @ 100 GPM
What is the frictin loss of 300' of 3" hose with 600 gpm?Answer 300' of 3" @ 600 GPM
What is the frictin loss of 400' of 3" hose with 800 gpm?Answer 400' of 4" @ 800 GPM
Verify your own friction loss problems with 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.
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