Steam Table

Saturated Steam Table by Temperature

Use this table when temperature is known and the water is at saturation. Pressure and temperature are linked along the saturation curve: specifying both does not determine steam quality. The liquid-volume column supplies vf for wet-mixture calculations; vapor volume is available in the lookup above.

Saturated Steam Table in psi and US Units

Use this chart for gauge pressure in psig. It includes the atmospheric-pressure offset before evaluating the same IAPWS equations as the SI table. For absolute pressure in psia, or a value between rows, use the lookup above. At 0 psig under this atmosphere assumption, Tsat is about 211.95°F.

Do not enter a psia reading in the psig column. At the same numerical pressure, the absolute pressure and saturation temperature would differ. Table values are rounded; the lookup retains calculation precision.

Common steam conditions: which table should you use?

1 bar absolute: saturated steam boils at about 99.61°C, with hg near 2,674.95 kJ/kg. 10 bar absolute: saturation temperature rises to about 179.89°C, and hg rises to approximately 2,777.12 kJ/kg. 100 psig: this is a gauge reading, so at standard atmosphere the absolute pressure is about 114.696 psia and its saturation temperature is about 337.88°F. Choose the units and condition in the lookup above to see your exact values.

Superheated example: at 10 bar absolute and 300°C, steam is above its 179.89°C saturation temperature. Its enthalpy is different from hg at 10 bar, so the saturated row cannot substitute for superheated properties. Wet steam example: at 10 bar and x = 0.90, calculate a mixture enthalpy from hf + x·hfg rather than using hg.

Pressure determines saturation temperature, but it does not by itself determine superheated-steam temperature or wet-steam quality. When both P and T are known outside saturation, first identify whether you are in a superheated or compressed-liquid region. The latter is outside this tool’s scope.

How to Read a Steam Table

First identify the fluid state. A saturation table applies when liquid water and vapor can coexist in equilibrium, or when you are using a saturated endpoint. A superheated state requires pressure and temperature; temperature alone is insufficient.

1. Identify the pressure basis. Read the instrument or problem statement for absolute or gauge pressure before converting units.
2. Choose the known input. Use the pressure table when pressure is known or the temperature table when saturation temperature is known.
3. Select the correct property and phase. Use hf for saturated liquid, hg for dry saturated vapor and hfg for the latent-heat difference.
4. Account for quality. A two-phase mixture with x below 1 has less enthalpy than dry saturated vapor at the same pressure.
5. Carry units into the calculation. Multiply a specific property by mass or mass flow only after checking that the time and unit bases agree.

The lowercase symbols h, u, s and v are properties per unit mass. Specific enthalpy h is useful in steady-flow energy balances; internal energy u excludes the flow-work term. Their relationship is h = u + pv, with pressure in kPa and volume in m³/kg when energy is in kJ/kg. Density is ρ = 1/v. For wet steam, calculate mixture specific volume first and take its reciprocal; linearly averaging liquid and vapor densities by quality is incorrect.

See TLV’s explanation of steam-table formats for the practical distinction between phase and pressure basis.

Gauge vs. Absolute Pressure: bar, kPa, MPa and psi

Absolute pressure = gauge pressure + local atmospheric pressure. Unit conversions are 1 MPa = 10 bar = 1,000 kPa. At standard atmosphere, the offset is 101.325 kPa = 1.01325 bar ≈ 14.69595 psi. Thus 0 psig corresponds to approximately 14.69595 psia, not a vacuum. A reading of 10 bar gauge corresponds to 11.01325 bar absolute at that reference atmosphere.

The lookup’s gauge options use the fixed standard-atmosphere offset and display that assumption. For a site at elevation or a measured atmospheric pressure that differs, convert using the actual local atmospheric pressure and choose an absolute-pressure input. A negative gauge reading can describe a vacuum relative to atmosphere while absolute pressure remains positive.

Unit changes in the lookup preserve the physical pressure and temperature. Switching from bar absolute to psig therefore changes the number. Each printed table keeps its stated units. US energy units use the International Table Btu, with 1 kJ/kg ≈ 0.4299226 Btu/lb and 1 m³/kg ≈ 16.01846 ft³/lb.

Wet Steam and Quality: Calculate Mixture Properties

Quality x is the mass of vapor divided by total liquid-plus-vapor mass. At x = 0 the state is saturated liquid; at x = 1 it is dry saturated vapor. Quality is defined for a saturated mixture. It is not an alternative temperature input for superheated steam, and 90% quality does not mean 90% of the volume is vapor.

Example at 1 bar absolute and x = 0.90: h = 417.4365 + 0.90 × 2257.5132 = 2,449.20 kJ/kg. Using hg = 2,674.95 kJ/kg would overstate the mixture enthalpy. If mass flow is 1,000 kg/h and that wet steam condenses to saturated liquid at the same pressure, the ideal latent heat released is approximately 1,000 × 0.90 × 2,257.513 / 3,600 = 564.38 kW, before losses or condensate subcooling.

If h, hf and hg are known at the same saturation pressure, quality follows from x = (h − hf)/(hg − hf). A result outside 0–1 indicates that the assumed saturated-mixture state is inappropriate, or that the inputs and reference basis need checking.

Superheated Steam Table and State Check

Steam is superheated when its temperature exceeds the saturation temperature at the same pressure. At 10 bar absolute, Tsat is approximately 179.89°C, so 200°C is superheated; a saturated-vapor enthalpy at 10 bar does not describe that 200°C state.

These 29 reference points cover common superheated conditions at 1–100 bar absolute. For any temperature between listed rows, use superheated mode in the lookup above: enter the actual pressure and steam temperature for direct IAPWS evaluation. Do not interpolate a saturated endpoint into superheated conditions. The supported envelope is above saturation through 800°C, at pressures up to 100 bar absolute. This lies within the implemented Region 2 equations. A temperature at or below saturation is rejected in this mode; the calculator does not silently apply vapor equations to liquid water.

For process heating, the energy released depends on both inlet and outlet states. Cooling superheated steam to saturation, condensing it and cooling the condensate are separate contributions. Spirax Sarco’s superheated-steam discussion explains the practical heat-transfer distinction.

Calculation Method, Rounding and Limits

These values are calculated with the IAPWS Industrial Formulation 1997, revised release R7-97(2012). Region 4 gives saturation pressure and temperature; Region 1 supplies saturated-liquid properties through 350°C; Region 2 supplies saturated-vapor and superheated-steam properties within the stated envelope. The lookup evaluates equations directly instead of interpolating the printed rows.

Saturation is limited to 0.01–350°C, approximately 0.00611657–165.29164 bar absolute. The page deliberately does not implement high-density Region 3, critical-region saturation, supercritical water, metastable steam, ice or salt solutions. Superheated mode is restricted to 100 bar absolute and 800°C. These page limits are narrower than the complete IF97 formulation.

The implementation, including the US-unit conversions and endpoint values, was checked against the release’s published verification values for Regions 1, 2 and 4 and an independent IF97 implementation. NISTIR 5078 provides independently published water and steam tables using IAPWS-95; small differences between IAPWS-95 and the industrial IF97 formulation, and between rounded displays, are expected.

Extra display digits are useful for calculations and do not establish measurement accuracy. Use the instrument’s uncertainty, actual fluid composition and the applicable engineering design method when specifying equipment or evaluating a process.

Steam Table FAQs

Related Engineering References