ISO 5167:2003 · Web app

Size or check orifice plates, nozzles, and Venturi tubes to ISO 5167.

Solve for flow rate, bore, or differential pressure. Gas, liquid, steam, and water, with IAPWS-IF97 properties for steam and water. Runs in the browser, so there is nothing to install.

Try it free Pricing: $490/seat/yr

No account, no credit card.

FlowCalc32 has been used by engineers at TotalEnergies, Petrobras, Siemens, GE, ABB, ArcelorMittal, INEOS, Technip, and many more.

What it calculates

Choose the unknown: flow rate, bore, or differential pressure. The result updates as you change any input. Gas, liquid, water, saturated steam, and superheated steam; density and viscosity for water and steam are computed from IAPWS-IF97.

Device	Standard	Variants
Orifice plate Corner, flange, and D and D/2 taps	ISO 5167-2	Corner, flange, and D and D/2 taps
Quadrant-edge orifice plate	ISO/TR 15377
ISA 1932 nozzle	ISO 5167-3
Long-radius nozzle	ISO 5167-3
Venturi nozzle	ISO 5167-3
Classical Venturi tube Machined, welded sheet-iron, and as-cast convergent	ISO 5167-4	Machined, welded sheet-iron, and as-cast convergent
Restriction orifice Bore for a given flow and permanent pressure loss	ISO 5167 equations	Bore for a given flow and permanent pressure loss

Details that matter in practice

Permanent pressure loss: ΔW is shown with every result, next to Re, β, C, ε and the ISO uncertainty.
Validity limits: Re and β are checked against the limits for the chosen device. Values outside them are marked, not hidden.
Choked flow and cavitation: Gas and steam are checked for critical flow, water for cavitation, and you are told when it occurs.
Expansion factor: When ΔP is more than 25 % of P1, ε is marked as extrapolated. You can enter your own value instead.
Thermal expansion: Pipe and plate diameters are corrected to the operating temperature, from the materials you choose.
Drain and vent holes: The flow correction for a drain or vent hole in the plate, from ISO/TR 15377.
Pipe sizes: Pick a nominal size and schedule (ASME B36.10 and B36.19) instead of typing the bore.
Mass, volume, or normal flow: kg/h, m³/h, Nm³/h and many more. Normal flow uses a reference state of your choice (0 °C, 15 °C, 60 °F, 70 °F, or your own).
Units per field: Every input has its own unit, so a datasheet can be entered as it is written. Defaults are set per workspace.
Steam: Set pressure from temperature, or temperature from pressure, at saturation with one click.

The full description of every input and result is in the help.

The report

Each device prints as a PDF datasheet: inputs, results, validity flags, the plate thickness limits for the pipe size, and the upstream and downstream straight lengths from ISO 5167-2 Table 3 and ISO 5167-3 Table 1, at 0 % and 0.5 % additional uncertainty. Your workspace logo goes in the header.

See a sample report (PDF)

First page of a sample FlowCalc report: pipe and orifice, operating conditions, and calculation result for an orifice plate with corner tapping.

Where the calculations come from

FlowCalc started as Turbo ORF in the 1980s and became FlowCalc32, a Windows program used by engineers at refineries, steel mills, and paper mills in more than 40 countries. This is a rewrite for the browser, with the same equations and the same answers.

FlowCalc32 has been used by engineers at

Oil and gas: TotalEnergies, Petrobras, Tüpraş, Caltex, Halliburton
Chemicals: INEOS, Solvay, Lubrizol
Steel, metals and mining: ArcelorMittal, Nucor, LKAB
Power and equipment: Siemens, GE, ABB, Iberdrola
Engineering: Technip, Bilfinger, Andritz
Pulp and paper: Stora Enso, Mondi, Metsä

FlowCalc is made and supported by Control Engineering Sweden Aktiebolag, Sweden: hello@flowcalc.cloud.

Working as a team

One set of records

Colleagues share a workspace and open the same devices, grouped in projects. When someone changes a device, it updates on everyone's screen.

Version history

Save a version before you change a device. Restore it later, or print the report of any version.

Nothing to install

Any current browser on Windows, Mac, Linux, or iPad. No licence keys, and everyone runs the same version.