Pressure drop or allowable flow for liquid, gas and steam lines, with fittings, elevation, choked-flow and flashing checks and a size table over every NPS of your schedule.
USD 29 one-time purchase
Download the sample report (PDF)
Need it once? Use it online: check your data free, unlock results from USD 9 for 3 runs.
What it does
Any fluid
Water and steam, gases and gas mixtures, hydrocarbons, solvents, glycols and brines, oils and petroleum fractions from the built-in fluid library, or your own density and viscosity.
Pipe and friction
NPS ½ to 36 inch in schedules 5S to XXS or your measured bore; Darcy–Weisbach with the Colebrook equation, laminar flow and the transition region.
27 fittings and valves
Elbows, tees, valves, entrances and exits with their K values, plus strainers or equipment as extra losses.
Gas and steam lines
Average density for small drops, isothermal flow for long lines and adiabatic flow with friction for plant lines, with the choking check and Mach number.
Size table
The same flow in every size of your schedule, with the smallest size that meets the velocity and pressure-drop guides for 15 services.
Flow for an allowed drop
The flow a line can pass for the pressure drop you have, and a one-page report for the calculation file.
Built for engineers
- Visible formulas — nothing hidden, so you can check every step.
- Fully referenced — methods from the standard references, checked against their published worked examples.
- Safe to share — sheets are protected against accidental edits, with an open password so you can still customise.
- Built-in input checks — clear warnings for impossible inputs and values outside typical ranges.
For engineering estimates; verify against site data. Code-based methods are aligned with the publicly documented procedure; they are not a licensed reproduction or a certification.
Preview the workbook
Real pages from the workbook with its built-in example loaded (example data, not a measured plant). Choose a page below, or select the large image to enlarge it.
A worked case
The case: 100,000 kg/h of water at 30 °C leaving a pump at 5 bar g through 100 m of 6-inch Schedule 40 pipe (154.08 mm) with fittings worth ΣK = 5.34. The workbook gives: velocity 1.50 m/s, Re 284,370, Darcy f = 0.01704, friction 0.123 bar per 100 m, total drop 18.3 kPa and 5.83 bar a at the outlet. The size table runs the same flow through every NPS and marks 6 inch as the size that meets the pump-discharge guides (1.22–1.98 m/s, at most 1.131 bar per 100 m, from Branan); the chart shows velocity against diameter.
Specification and checks
| Format | Excel workbook (.xlsx), no macros |
| Version | v1.0 |
| Works in | Excel 2010 or later, Windows and Mac |
| Units | SI, US and British, mixed freely |
| Includes | Guide tab with method and references, calculator, print-ready report |
| Checked against | Perry's Example 6 (fittings and valves) gives the same tank level, 0.74 m against 0.73 m; Perry's Example 8 (choked air flow) gives 2.73 kg/s against 2.7 kg/s; 17 of 17 checks against an independent model within tolerance. |
| Free version | Try the online calculator |
Free calculator, online tool or Excel tool?
| Free calculator | Online tool | Excel tool | |
|---|---|---|---|
| What it does | Friction, fittings and elevation by Darcy-Weisbach, plus velocity and pressure drop for every Schedule 40 size. | The full Excel tool, run in your browser | Pressure drop or allowable flow for liquid, gas and steam lines, with fittings, elevation, choked-flow and flashing checks and a size table over every NPS of your schedule. |
| Cost | Free, no sign-up | 3 runs for USD 9, or every online tool for USD 15 a month | USD 29 once, yours to keep |
| Input checks and findings | Basic warnings | Every input checked, with findings and recommendations | Every input checked, with findings and recommendations |
| Report for your calculation file | Print the web page | Printable results sheet | Print-ready report with your plant, tag, document number, revision and sign-off |
| Formulas | Method described on the page | Method described in the guide | Every formula visible in its cell |
| Save, edit and rerun your cases | — | Each run separately | Yes — keep and edit your own file |
| Works offline, on a plant PC | — | — | Yes — Excel 2010 or later, Windows and Mac |
Compatibility, licence and support
| File | Excel workbook (.xlsx), no macros, version v1.0; works in Excel 2010 or later on Windows and Mac. Sheets are protected against accidental edits, with an open password so you can customise. |
| Licence | Single user. A team licence (up to 5 named users) is 3 × the shop price; site licences on request — licence terms. |
| Updates | Updates to this major version are included; download them again from the link in your receipt. |
| Support | Email [email protected] with your order number — questions on the method, your inputs or your results are welcome. |
| Refunds | If the tool does not work as described, or has an error we cannot fix, email [email protected] with your order number within 14 days of purchase and we will refund you in full. Refunds are not offered for a change of mind once a file has been downloaded. Read the full refund policy. |