Pipes Relative Capacities
Reference data and engineering information about pipes relative capacities for piping systems applications.
pipesrelativecapacities
Overview
Engineering reference data for Pipes Relative Capacities in piping systems.
Key Formulas
Continuity
Mass conservation in pipe flow.
Pressure Drop
Darcy-Weisbach equation.
Pipe Area
Cross-sectional area of a pipe.
Variables
| Symbol | Description | Unit |
|---|---|---|
| Pipe diameter | m | |
| Flow velocity | m/s | |
| Pressure drop | Pa | |
| Friction factor | — |
Pipe Inside Dimensions
16 rows
Nominal Size(inches) | Inside Area(in²) |
|---|---|
| 1/8 | 0.06 |
| 1/4 | 0.1 |
| 3/8 | 0.19 |
| 1/2 | 0.3 |
| 3/4 | 0.53 |
| 1 | 0.86 |
| 1 1/4 | 1.5 |
| 1 1/2 | 2.04 |
| 2 | 3.36 |
| 2 1/2 | 4.79 |
| 3 | 7.39 |
| 3 1/2 | 9.89 |
| 4 | 12.73 |
| 5 | 20 |
| 6 | 28.89 |
| 8 | 50.02 |
Source: engineeringtoolbox.com
Relative Capacity Table
The relative capacity indicates how many smaller pipes are needed to match the flow capacity of one larger pipe, based on cross-sectional area ratios.
16 rows
Pipe Size(inches) | vs 1/8" | vs 1/4" | vs 1/2" | vs 1" | vs 2" | vs 4" |
|---|---|---|---|---|---|---|
| 1/8 | 1 | — | — | — | — | — |
| 1/4 | 1.67 | 1 | — | — | — | — |
| 3/8 | 3.17 | 1.9 | — | — | — | — |
| 1/2 | 5 | 3 | 1 | — | — | — |
| 3/4 | 8.83 | 5.3 | 1.77 | — | — | — |
| 1 | 14.33 | 8.6 | 2.87 | 1 | — | — |
| 1 1/4 | 25 | 15 | 5 | 1.74 | — | — |
| 1 1/2 | 34 | 20.4 | 6.8 | 2.37 | — | — |
| 2 | 56 | 33.6 | 11.2 | 3.91 | 1 | — |
| 2 1/2 | 79.83 | 47.9 | 15.97 | 5.57 | 1.43 | — |
| 3 | 123.17 | 73.9 | 24.63 | 8.59 | 2.2 | — |
| 3 1/2 | 164.83 | 98.9 | 32.97 | 11.5 | 2.94 | — |
| 4 | 212.17 | 127.3 | 42.43 | 14.8 | 3.79 | 1 |
| 5 | 333.33 | 200 | 66.67 | 23.26 | 5.95 | 1.57 |
| 6 | 481.5 | 288.9 | 96.3 | 33.59 | 8.6 | 2.27 |
| 8 | 833.67 | 500.2 | 166.73 | 58.16 | 14.89 | 3.93 |
Source: engineeringtoolbox.com
Application Notes
- System sizing: Use relative capacity when converting between pipe sizes in a distribution network
- Parallel piping: Multiple smaller pipes can replace a single larger pipe when capacity ratios match
- Flow assumption: Relative capacity based on area ratio assumes equal flow velocity across all pipe sizes