IAPWSIF97
Region 5 Steam Property Values
IAPWS issued Revised Release of IAPWSIF97 in August 2007, in which the pressure range for Region 5 is extended from 10 MPa to 50 MPa and revised are the numerical values of the coefficients and exponents of the residual part of the dimensionless Gibbs free energy for Region 5, presented in IAPWSIF97 Table 38.
By this revision of Region 5 coefficients, the Region 5 property values calculated by the revised coefficients are different from those calculated by original coefficients.
The 2007 edition of IAPWSIF97 document provides the following table for computerprogram verification.
The original edition of IAPWSIF97 document provides different property values for the first state of T = 1500 K and p = 0.5 MPa as below.

T = 1500 K, 

p = 0.5 MPa 
v / (m3/kg) 
0.138 455 354 x 10^1 
h / (kJ/kg) 
0.521 976 332 x 10^4 
u / (kJ/kg) 
0.452 748 654 x 10^4 
s / (kJ/kg/K) 
0.965 408 431 x 10^1 
Cp / (kJ/kg/K) 
0.261 610 228 x 10^1 
w / (m/s) 
0.917 071 933 x 10^3 
As seen in the tables, the property value differences between the 2007 edition and original edition are considerable.
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