Line sizing and pressure drop.
Size a liquid line from standard Schedule 40 pipe and estimate velocity, Reynolds number, friction factor and pressure drop.
Results
Preliminary estimate for early engineering. Check against your design basis, standards and vendor data.
Method
All Schedule 40 sizes for this flow
| Size | ID, mm | Velocity, m/s | ΔP, bar/100 m | Regime |
|---|---|---|---|---|
| ½″ | 15.8 | 28.34 | 663.314 | Turbulent |
| ¾″ | 20.93 | 16.15 | 151.917 | Turbulent |
| 1″ | 26.64 | 9.97 | 43.193 | Turbulent |
| 1½″ | 40.89 | 4.23 | 4.727 | Turbulent |
| 2″ (within target velocity) | 52.5 | 2.57 | 1.322 | Turbulent |
| 3″ (within target velocity) | 77.93 | 1.16 | 0.182 | Turbulent |
| 4″ | 102.26 | 0.68 | 0.047 | Turbulent |
| 6″ | 154.05 | 0.3 | 0.006 | Turbulent |
| 8″ | 202.72 | 0.17 | 0.002 | Turbulent |
| 10″ | 254.51 | 0.11 | 0.001 | Turbulent |
| 12″ | 303.23 | 0.08 | 0 | Turbulent |
Highlighted rows are within your target velocity range.
How it is calculated
v = Q / (π D² / 4) · Re = ρ v D / μ · ΔP = f (L / D) (ρ v² / 2)
The Darcy friction factor f is 64 / Re in laminar flow. In turbulent flow it comes from the Colebrook–White equation, solved iteratively from a Swamee–Jain starting value:
1 / √f = −2 log10( (ε / D) / 3.7 + 2.51 / (Re √f) )
Inside diameters are ASME B36.10 Schedule 40. The method assumes incompressible flow: use it for liquids, and for gases only where the pressure drop is a small fraction of the inlet pressure.
Read: equipment sizing basics →All engineering tools →Size equipment from your own balance in Black Owl ↗
Calculated with the free engineering tools at nicuzn.com/tools. Preliminary estimate for early engineering; check against your design basis, applicable standards and vendor data before use.