The fps to gpm calculator (feet per second to gallons per minute) is designed to convert water flow rates between different measurement units.
When you have a pipe with water flowing at 2.5 feet per second, and you need to know the flow rate in gallons per minute. Using the fps to gpm converter for a 4-inch diameter pipe:
pipe_diameter = 4 inches
flow_velocity = 2.5 fps
calculated_gpm = 97.34 GPM
FPS to GPM Calculator
FPS (Feet per Second) | GPM (Gallons per Minute) |
---|---|
0.5 | 1.02 |
1 | 2.04 |
1.5 | 3.06 |
2 | 4.08 |
2.5 | 5.10 |
3 | 6.12 |
3.5 | 7.14 |
4 | 8.16 |
4.5 | 9.18 |
5 | 10.20 |
10 | 20.40 |
20 | 40.80 |
30 | 61.20 |
40 | 81.60 |
50 | 102.00 |
60 | 122.40 |
70 | 142.80 |
80 | 163.20 |
90 | 183.60 |
100 | 204.00 |
200 | 408.00 |
300 | 612.00 |
400 | 816.00 |
500 | 1020.00 |
600 | 1224.00 |
700 | 1428.00 |
800 | 1632.00 |
900 | 1836.00 |
1000 | 2040.00 |
FPS to GPM Conversion Chart
Pipe Diameter (inches) | Flow Velocity (FPS) | Calculated GPM |
---|---|---|
1 | 1 | 7.48 |
1 | 2 | 29.92 |
1 | 3 | 67.25 |
1 | 4 | 120.70 |
1 | 5 | 193.25 |
2 | 1 | 29.92 |
2 | 2 | 119.68 |
2 | 3 | 268.31 |
2 | 4 | 477.46 |
2 | 5 | 740.98 |
3 | 1 | 67.25 |
3 | 2 | 268.31 |
3 | 3 | 602.44 |
3 | 4 | 1077.93 |
3 | 5 | 1680.83 |
4 | 1 | 120.70 |
4 | 2 | 477.46 |
4 | 3 | 1077.93 |
4 | 4 | 1925.52 |
4 | 5 | 3038.06 |
6 | 1 | 272.34 |
6 | 2 | 1089.36 |
6 | 3 | 2440.67 |
6 | 4 | 4320.00 |
6 | 5 | 6480.00 |
FPS to GPM Conversion Formula
The formula for converting FPS to GPM is:
GPM = FPS × (Pipe Area in sq. ft) × (448.83 gal/min/cfs)
Where:
- FPS = Flow velocity in feet per second
- Pipe Area = π × (pipe diameter in feet)² ÷ 4
- 448.83 = Conversion factor from cubic feet per second to gallons per minute
For a 6-inch (0.5 ft) diameter pipe with 3 FPS flow:
Pipe Area = π × (0.5 ft)² ÷ 4 = 0.196 sq. ft
GPM = 3 × 0.196 × 448.83 = 264.37 GPM
How to Convert FPS to GPM?
Converting FPS to GPM involves these step-by-step calculations:
- Determine pipe diameter in feet: 8-inch (0.667 ft)
- Calculate pipe cross-sectional area:
- Multiply by flow velocity in FPS
- Apply the conversion factor
Converting 4 FPS in an 8-inch (0.667 ft) diameter pipe:
- Area = π × (0.667)² ÷ 4 = 0.349 sq. ft
- Flow = 4 FPS × 0.349 × 448.83 = 626.97 GPM
How do you convert flow rate to GPM?
Converting various flow rates to GPM requires different conversion factors:
- From cubic feet per second (CFS): Multiply by 448.83
- From liters per minute (LPM): Multiply by 0.264172
- From cubic meters per hour (m³/h): Multiply by 4.402868
Example:
Converting 0.5 CFS to GPM:
GPM = 0.5 × 448.83 = 224.415 GPM
What is FPS in water?
FPS in water refers to the linear velocity of water flow measured in feet per second.
In a residential water supply system, typical flow velocities range from 4-8 FPS:
Recommended velocity = 6 FPS
Maximum velocity = 8 FPS (to prevent erosion)
Minimum velocity = 2 FPS (to prevent sediment)
Sources:
- U.S. Geological Survey Water Resources https://www.usgs.gov/mission-areas/water-resources
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