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.

	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
GPM
	Hose Diameter in Inches (100 ft hose length)
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

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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