The Vapour Pressure of Water

It is sometimes useful to know the vapour pressure of water. Below is a list of high-precision values. This uses the Wagner & Pruss equation (1993 J Phys Chem Ref Data 22, pp 783-787).

The table uses the modern single-fixed-point thermodynamic temperature scale in which the triple point of water is 273.16 K exactly, and celsius degrees are defined as K - 273.15. The boiling point of water is no longer a fixed point. Referring to the table, the "normal boiling point" (i.e. at 1 standard atmosphere pressure = 101325 Pa) is 99.9743°C, while the IUPAC standard boiling point (i.e. at 100 kPa) is 99.6059°C.

Note 1.