Waste Water Piping - Flow Capacitiy vs. Dimension
In sewage piping and pumping systems the fluid flow rate must be kept within certain limits to avoid operating problems.
In sewage piping and pumping systems the flow velocity must exceed certain limits to maintain trouble free operation and to avoid settling and sedimentation of solids:
- for horizontal wastewater pipe systems with solids the speed should exceed 3 ft/sec
- for wastewater water system with organic solids the speed should exceed 2 ft/sec
On the other hand, the flow velocity should not exceed certain limits to avoid potential wear and tear due to erosion and abrasion:
- the flow velocity in high-grit sewage handling systems should not exceed 12 ft/sec
- the flow velocity in sewage systems with low grit concentrations should not exceed 18 ft/sec
Flow rate capacities in U.S. gal for sewage piping and pumping systems within the limitations:
| Pipe Dimension (inches) | Flow Rate (US GPM) | |||
|---|---|---|---|---|
| Minimum Velocity | Maximum Velocity | |||
| 2 ft/sec (0.6 m/s) | 3 ft/sec (0.9 m/s) | 12 ft/sec (3.6 m/s) | 18 ft/sec (5.4 m/s) | |
| 3 | 45 | 65 | 270 | 400 |
| 4 | 80 | 120 | 480 | 700 |
| 6 | 180 | 260 | 1050 | 1600 |
| 8 | 300 | 500 | 1900 | 2800 |
| 10 | 500 | 750 | 3000 | 4400 |
| 12 | 700 | 1100 | 4300 | 6400 |
Note! - based on clean pipes. The friction coefficient may vary with the pipe material.
