Line Sizing Calculator

Incompressible Line Sizing Calculator Guide (PDF)

This calculator determines the pressure drop through a pipeline. It is suitable for incompressible flow. Incompressible flow refers to liquids in all cases and gases or vapours where the pressure drop is less than 10% of the upstream pressure. This calculator can also be used for gases or vapours where the pressure drop is up to 40% of the upstream pressure if the average fluid density is used.

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

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