飽和水蒸気量
P ws = P c × exp  ( A × x + B × x 1.5 + C × x 3 + D × x 6 1 − x ) {\displaystyle P_{\text{ws}}=P_{c}\times \exp({\dfrac {A\times x+B\times x^{1.5}+C\times x^{3}+D\times x^{6}}{1-x}})}
ここで、
P ws {\displaystyle P_{\text{ws}}} [kPa] ワグナーの厳密水蒸気圧
P c = 22120 {\displaystyle P_{c}=22120} [kPa] 臨界圧
T c = 647.3 {\displaystyle T_{c}=647.3} [K] 臨界温度
T {\displaystyle T} [K] 絶対温度
x = 1 − T T c {\displaystyle x=1-{\dfrac {T}{T_{c}}}}
A = − 7.76451 {\displaystyle A=-7.76451}
B = 1.45838 {\displaystyle B=1.45838}
C = − 2.