Friction Loss Cheat Sheet

This table shows friction loss for 100 ft section of most common sized fire hose (.75" to 6"). In the table, find the GPM shown along the left (green) and the hose diameter shown along on the top. The table's intersection of the GPM & Diameter is the friction loss measured in PSI. Links at the top of each column go to detailed friction loss tables for each hose size.

Example: 100 ft of 1.75 inch fire hose with 150 GPM has 34.9 PSI friction loss.
200 ft of 1.75 inch fire hose with 150 GPM will be 34.9 PSI (times 2) friction loss. Or 69.8 PSI.
You can find the answer highlighted in yellow (below) or visit the friction loss calculator.


GPM
Hose Diameter in Inches (100 ft hose length)
0.75 1.00 1.25 1.50 1.75 2.00 2.50 3.00 3.50 4.00 4.50 5.00 6.00
5 2.8 0.4 0.2 0.1
10 11 1.5 0.8 0.2 0.2 0.1
15 24.8 3.4 1.8 0.5 0.3 0.2
20 44 6 3.2 1 0.6 0.3 0.1
25 68.8 9.4 5 1.5 1 0.5 0.1
30 99 13.5 7.2 2.2 1.4 0.7 0.2 0.1
40 176 24 12.8 3.8 2.5 1.3 0.3 0.1 0.1
50 37.5 20 6 3.9 2 0.5 0.2 0.1 0.1
60 54 28.8 8.6 5.6 2.9 0.7 0.2 0.1 0.1
70 73.5 39.2 11.8 7.6 3.9 1 0.3 0.2 0.1
80 96 51.2 15.4 9.9 5.1 1.3 0.4 0.2 0.1 0.1 0.1
90 121.5 64.8 19.4 12.6 6.5 1.6 0.5 0.3 0.2 0.1 0.1
100 150 80 24 15.5 8 2 0.7 0.3 0.2 0.1 0.1 0.1
125 234.4 125 37.5 24.2 12.5 3.1 1.1 0.5 0.3 0.2 0.1 0.1
150 180 54 34.9 18 4.5 1.5 0.8 0.5 0.2 0.2 0.1
175 245 73.5 47.5 24.5 6.1 2.1 1 0.6 0.3 0.2 0.2
200 96 62 32 8 2.7 1.4 0.8 0.4 0.3 0.2
250 150 96.9 50 12.5 4.2 2.1 1.3 0.6 0.5 0.3
300 216 139.5 72 18 6.1 3.1 1.8 0.9 0.7 0.5
350 294 189.9 98 24.5 8.3 4.2 2.5 1.2 1 0.6
400 248 128 32 10.8 5.4 3.2 1.6 1.3 0.8
450 162 40.5 13.7 6.9 4.1 2 1.6 1
500 200 50 16.9 8.5 5 2.5 2 1.3
600 288 72 24.4 12.2 7.2 3.6 2.9 1.8
700 98 33.2 16.7 9.8 4.9 3.9 2.5
800 128 43.3 21.8 12.8 6.4 5.1 3.2
900 162 54.8 27.5 16.2 8.1 6.5 4.1
1000 200 67.7 34 20 10 8 5
1500 152.3 76.5 45 22.5 18 11.3
2000 270.8 136 80 40 32 20

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

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