FieldEngineersKitEngineering Reference & ASME Code Basis
1. Core Formula & Variable Definitions
IAPWS-IF97 Industrial Formulation for the Thermodynamic Properties of Water and Steam · ASME Steam Tables (IAPWS-IF97 basis) · IAPWS Release on the Viscosity of Ordinary Water Substance (2008)
ρ = 1 / v(T, P) [kg/m³ or lb/ft³]
Cp = (∂h/∂T)P [kJ/(kg·K) or Btu/(lb·°F)]
ν = μ / ρ · μ from IAPWS viscosity formulation
IAPWS-IF97 Region 1 liquid screening · Region 4 saturation for boiling point / phase
Field screening for compressed / subcooled liquid water using IAPWS-IF97 Region 1–aligned property bands and Region 4 saturation pressure. Viscosity and thermal conductivity use IAPWS industrial liquid correlations. Do not use for steam, two-phase, or supercritical states without a full steam-table verification.
- ρ (Density) — 1 / v(T, P) — primary hero value with C_p.
- C_p (Specific heat capacity) — Isobaric heat capacity of liquid water.
- μ (Dynamic viscosity) — IAPWS industrial liquid viscosity (Pa·s / cP).
- ν (Kinematic viscosity) — μ / ρ (m²/s or cSt).
- T, P (Temperature & pressure) — °C/°F and bar/psi state point for Region 1 liquid.
2. Screening Rules Matching This Calculator
Returns IAPWS-IF97 Region 1–aligned liquid water properties at a single (T, P) point. Phase, steam, and two-phase duties remain out of scope.
Hero ρ and C_p assume liquid water. Confirm T < Tsat(P) before using values in Darcy or heat-balance screens.
Stay inside the industrial liquid screening window (or °F / psi equivalents via UnitSwitcher).
Matches the Quick Reference row and the calculator default (C_p ≈ 4.182 kJ/kg·K, μ ≈ 1.00 cP).
Use a full steam-table / IAPWS multi-region tool for vapor or near-critical states. Dissolved solids are not modeled.
Quick Reference Lookup Table
| T | P | ρ | C_p | μ | Phase note |
|---|---|---|---|---|---|
| 20 °C | 1.013 bar | 998.2 kg/m³ | 4.182 kJ/kg·K | 1.00 cP | Subcooled |
| 20 °C | 1 bar | 998.2 kg/m³ | 4.182 kJ/kg·K | 1.00 cP | Subcooled |
| 40 °C | 1 bar | 992.2 kg/m³ | 4.179 kJ/kg·K | 0.65 cP | Subcooled |
| 60 °C | 1 bar | 983.2 kg/m³ | 4.185 kJ/kg·K | 0.47 cP | Subcooled |
| 80 °C | 1 bar | 971.8 kg/m³ | 4.196 kJ/kg·K | 0.35 cP | Subcooled |
| 100 °C | 1 bar | 958.4 kg/m³ | 4.216 kJ/kg·K | 0.28 cP | Near sat. |
| 100 °C | 1.013 bar | 958.4 kg/m³ | 4.216 kJ/kg·K | 0.28 cP | Sat. liquid |
| 150 °C | 5 bar | 917.0 kg/m³ | 4.316 kJ/kg·K | 0.18 cP | Compressed |
| 200 °C | 20 bar | 864.7 kg/m³ | 4.505 kJ/kg·K | 0.13 cP | Compressed |
| 68 °F | 14.7 psi | 62.3 lb/ft³ | 1.000 Btu/lb·°F | 1.00 cP | Subcooled |
| 212 °F | 14.7 psi | 59.8 lb/ft³ | 1.007 Btu/lb·°F | 0.28 cP | Near sat. |
| 300 °F | 100 psi | 57.3 lb/ft³ | 1.03 Btu/lb·°F | 0.20 cP | Compressed |
Screening values from IAPWS-IF97 Region 1–aligned liquid polynomials. Near-saturation duties (100 °C · 1 bar) evaluate as liquid for field use — verify phase with a full steam table when P < Psat(T).
3. Applicability & Fluid Limits
This tool is pure water (H₂O) liquid screening. Fluid chemistry and phase boundaries are outside the property polynomials.
| Group / Regime | Range / Condition | Limit / Criterion | Engineering Notes |
|---|---|---|---|
| Pure liquid water (Region 1) | ≈ 0–350 °C (industrial liquid band) | N/A — thermodynamic properties | Default medium. Density and C_p follow IAPWS-IF97 Region 1–aligned screening; μ from IAPWS viscosity release. |
| Near-saturation liquid | T approaching Tsat(P) | Verify P ≥ Psat(T) | Values may still be reported as liquid near boiling — confirm phase before using in hydraulic models. |
| Steam / wet steam / supercritical | Outside Region 1 liquid | Out of scope | Do not treat vapor or critical states with this calculator. Open a full steam-table evaluation. |
| Brine / glycol / process mixtures | Not modeled | Out of scope | Dissolved solids and antifreeze shift ρ, μ, and C_p. Use mixture property data instead. |
Code Applicability & Safety Boundaries
- IAPWS-IF97 Region 1 liquid screening only — not a multi-region steam-table substitute
- Phase status is indicative; critical duties need ASME steam tables or equivalent software
4. Step-by-Step Worked Example
Field VerificationShowHide
Worked example — 20 °C · 1.013 bar
Look up liquid water density and specific heat at ambient process conditions for Darcy friction / heat-balance screening.
Confirm liquid state
Density & C_p
Transport properties
5. How to look up water thermodynamic properties
- 1
Select unit system
Use the navbar UnitSwitcher for metric (°C, bar) or imperial (°F, psi).
- 2
Enter temperature and pressure
Stay within 0–350 °C and 0.1–200 bar (or °F / psi equivalents) for Region 1 liquid screening.
- 3
Read ρ · C_p hero and viscosity summary
Hero shows density and specific heat; summary lists μ, ν, v, and k.
- 4
Check phase / boiling point rows
Confirm Subcooled / Compressed Liquid status. If vapor is possible, open a steam table.
6. Frequently Asked Questions & Technical References
ShowHide
At 20 °C · 1.013 bar, hero density is about 998.2 kg/m³ with C_p ≈ 4.182 kJ/kg·K — the common IAPWS / ASME steam-table ambient liquid values.
No for final design. This calculator is IAPWS-IF97 Region 1 liquid screening. Steam / two-phase / supercritical states need a full steam-table evaluation.
ν = μ / ρ. Dynamic viscosity μ uses an IAPWS industrial liquid correlation; density comes from the Region 1–aligned liquid model at your T and P.
Carry temperature/pressure into pipe-wall-thickness, flange-dimension-weight, or pressure-drop-friction for piping design and Darcy friction screening.