Steam Tables Lookup

Interpolated table lookup for study and screening. Not a design basis for pressure equipment. These are values read between the rows of a vendored CSV, not IAPWS-IF97 evaluated from the formulation. Boilers, pressure vessels and steam systems fail energetically, and nothing on this page is a substitute for the code, certified software, or a qualified engineer. Open for the full scope limits.

What this tool actually does

Looks up water and steam properties in vendored saturation, compressed-liquid, superheated and supercritical tables and interpolates between grid points. Outputs have been spot-checked against the NIST WebBook in all four regions, and the tool ships a self-test suite that re-proves the parser, the grid points, the interpolation and the reverse round trips.

Interpolation between tabulated points is not the same as evaluating the IAPWS-IF97 formulation, and the difference grows wherever properties change quickly.

Where interpolated values go soft

Near the critical point, where properties change steeply and a linear step between grid points is a poor approximation.
Across a phase boundary. Interpolating between a liquid row and a vapour row produces a number that describes no real state.
In table gaps and at the edges, where the grid is coarse or the region ends. Extrapolation is not interpolation.
In derived quantities. Errors in enthalpy and entropy propagate into any efficiency, duty or work calculation built on them, and a small property error can become a large equipment error.

Nothing here computes transport properties, non-equilibrium or two-phase flow, steam quality in a real pipe, or the behaviour of anything other than pure water. Feedwater chemistry, dissolved gases and contaminants are outside the model entirely.

Never use this for

Pressure vessel or boiler design, rating or re-rating under ASME BPVC, PED or any equivalent code.
Relief valve or rupture disc sizing, or any overpressure protection case.
Piping design or flexibility analysis under ASME B31.1 or B31.3.
Turbine, heat exchanger or plant performance guarantees, acceptance testing, or contractual figures.
Custody transfer, emissions reporting, or any regulatory or certification submission.

Steam at operating conditions carries enough stored energy that a wrong number is not an inconvenience. Burns, equipment destruction and fatalities are the failure modes of this domain.

What to use instead when it matters

Evaluate properties from IAPWS-IF97 in certified software, or take them from the published steam tables for your code. Confirm the region, the reference state and the units. Have the calculation and the equipment reviewed by a qualified mechanical or process engineer working to the governing code.

No warranty. No liability. You assume all risk. This page, its data and its interpolated values are provided as-is and as-available, without warranty of any kind, express or implied, including accuracy, completeness, timeliness, reliability, fitness for a particular purpose, merchantability, engineering or professional suitability, regulatory or code acceptability, or non-infringement. To the maximum extent permitted by law, the author accepts no liability for any loss, injury, death, damage, cost or claim arising from use of or reliance on this page.

Independent verification required. Check every value against IAPWS-IF97, the published steam tables for the governing code, and a qualified engineer before it informs any design, operation or purchase. The formulation, the code and professional judgement control; where this page disagrees with them, this page is wrong.

Consequential damages excluded. To the maximum extent permitted by law, in no event will the author or maintainers be liable for any direct, indirect, incidental, special, exemplary, punitive or consequential damages, including loss of use, data, profits or business interruption, however caused and on any theory of liability, whether in contract, strict liability or tort including negligence, arising out of or in connection with this page, even if advised of the possibility of such damage.

Indemnity. By using this page you agree to indemnify and hold harmless the author and maintainers against any claim, demand, loss or expense arising out of your use of it or of anything derived from it.

Severability. If any part of this notice is held unenforceable, the remainder continues to apply, and the unenforceable part is limited to the least extent necessary rather than struck out.

State Lookup

Interpolates against vendored LearnChemE steam table CSVs. All math runs in SI units; display units are converted at the boundary.

Lookup mode Units Pressure units Example

Inputs

Load tables and enter a state to compute properties.

Interpolation details will appear after a lookup.

Phase Context

Compute a state to see its phase region and saturation distance.

Charts

Charts use the saturated CSV rows as context and overlay the current state plus pinned comparison states when they have plottable coordinates.

Interpolated between table rows. Values go soft near the critical point, across a phase boundary and in table gaps, and nothing here is a design basis for a boiler, pressure vessel or relief case. See the full disclaimer at the top of the page.

Compute a state to draw saturation context charts.

State Comparison

Pin State A and State B to compare property deltas.

Internal Consistency Tests

The test runner checks parser counts, exact CSV grid points, midpoint interpolation, reverse round trips, table-gap handling, and unit round trips.

Run tests to compare interpolation paths against the vendored CSV rows.

Data Source

CSV data is vendored from LearnChemE Steam Tables, authored by Neil Hendren at CU Boulder. The CSV metadata carries an MIT-style permissive notice retained in each source data file; broader LearnChemE pages identify LearnChemE work as CC BY-SA 4.0.