Plastic Pipes - Friction Head Loss vs. Water Flow
Friction head loss (ft/100 ft) vs. water flow in plastic pipes like PVC, PP, PE or PEH.
The friction head loss (feet H2O per 100 feet pipe) in straight plastic pipes made of PVC, PP, PE, PEH or similar - can be estimated from the table below.
Head losses are calculated for PVC pipe Schedule 40 by using the Hazen-Williams equation and the Hazen-Williams roughness constant c = 145. Note that minor loss in fittings must be added when calculating total head loss in a pipe line.
For full table with larger dimensions - rotate the screen!
| Friction Head Loss (ft H2O/100 ft pipe) | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Volume Flow | Nominal Pipe Diameter (inches) | |||||||||||
| (GPM)1) | (GPH)2) | |||||||||||
| 3/8 | 1/2 | 3/4 | 1 | 1 1/4 | 1 1/2 | 2 | 2 1/2 | 3 | 4 | 6 | ||
| Nominal Inside Diameter (inches) | ||||||||||||
| 0.493 | 0.622 | 0.824 | 1.049 | 1.380 | 1.610 | 2.067 | 2.469 | 3.068 | 4.026 | 6.065 | ||
| 1 | 60 | 3.3 | 1.1 | 0.3 | ||||||||
| 2 | 120 | 11.8 | 3.8 | 1.0 | 0.3 | 0.1 | ||||||
| 4 | 240 | 42.5 | 13.7 | 3.5 | 1.1 | 0.3 | 0.1 | |||||
| 5 | 300 | 64.2 | 20.7 | 5.3 | 1.6 | 0.4 | 0.2 | |||||
| 6 | 360 | 29.0 | 7.4 | 2.3 | 0.6 | 0.3 | ||||||
| 8 | 480 | 49.5 | 12.6 | 3.9 | 1.0 | 0.5 | 0.1 | |||||
| 10 | 600 | 74.7 | 19.0 | 5.9 | 1.6 | 0.7 | 0.2 | 0.1 | ||||
| 20 | 1200 | 68.6 | 21.2 | 5.6 | 2.6 | 0.8 | 0.3 | 0.1 | ||||
| 30 | 1800 | 11.8 | 5.6 | 1.7 | 0.7 | 0.2 | ||||||
| 40 | 2400 | 20.1 | 9.5 | 2.8 | 1.2 | 0.4 | 0.1 | |||||
| 50 | 3000 | 14.4 | 4.3 | 1.8 | 0.6 | 0.2 | ||||||
| 60 | 3600 | 20.1 | 6.0 | 2.5 | 0.9 | 0.2 | ||||||
| 70 | 4200 | 7.9 | 3.3 | 1.2 | 0.3 | |||||||
| 80 | 4800 | 10.2 | 4.3 | 1.5 | 0.4 | |||||||
| 90 | 5400 | 12.6 | 5.3 | 1.9 | 0.5 | |||||||
| 100 | 6000 | 6.5 | 2.3 | 0.6 | 0.1 | |||||||
| 125 | 7500 | 9.8 | 3.4 | 0.9 | 0.1 | |||||||
| 150 | 9000 | 4.8 | 1.3 | 0.2 | ||||||||
1) GPM = U.S. gallons per minute
2) GPH = U.S. gallons per hour
- 1 U.S. gallon/min = 6.30888×10-5 m3/s = 0.227 m3/h = 0.0631 dm3(liter)/s = 2.228×10-3 ft3/s = 0.1337 ft3/min = 0.8327 Imperial gal (UK)/min
- 1 ft H2O = 0.3048 m H2O = 0.4335 psi = 62.43 lbs/ft2
Example - Friction Head Loss in a Plastic Pipe
A flow of 10 GPM in a 2" pipe gives a head loss of 0.2 feet water column per 100 feet of pipe.
