Line Sizing Calculator

The calculator determines the static pressure drop and frictional pressure drop through a line assuming incompressible flow.

The assumption of incompressible flow is reasonable for gases and vapours where the calculated pressure drop is less than 10% of the upstream pressure.

Up to 3 pipes of different diameters can be handled in the calculation of the line pressure drop.

1. Enter the source and destination of the line and the line number
2. Enter the fluid details and physical properties
3. Enter the elevations of each end of the line
4. Choose the nominal diameter and schedule of 1, 2 or all 3 pipes from the drop down lists
5. The calculator will determine the inside diameter of each selected pipe
6. Enter a length for 1, 2 or all 3 pipes
7. Enter an absolute roughness for each pipe.  Typical values:
   • Commercial steel: 0.046 mm
   • Drawn tubing (brass, lead, glass): 0.002 mm
   • Asphalted cast iron: 0.122 mm
   • Galvanized iron: 0.152 mm
   • Cast iron: 0.259 mm
8. Enter the quantities of each type of fitting for each pipe if known
9. If the type and quantities of each fitting are unknown, enter a fitting factor. Typical factors for 50 metre long lines:
   • 3" diameter and smaller: 1.5
   • 4" and 6" diameter: 2.0
   • 8" diameter and larger: 2.5
10. Click the "Calculate" button
11. The calculator will determine the static and frictional pressure drop through 1, 2 or all 3 pipes making up the line
12. "Reasonable" fluid velocities:
    • Liquids: up to 3 m/s
    • Gases: up to 20 m/s