Error estimating from Formulation IF–97 values of specific volume, isobaric heat capacity, saturation pressure and sound velocity are represented in pic. 2, 3, 4, 5. They are tolerance, within the bounds of them may be lie the values of interesting properties. The title «tolerance can't be determine» reference to area where used the extrapolated from [1] values.
Tolerance for dynamic viscosity: with pressure up to 100 MPa for liquid: up to 250 °C – 1%, up to 300 °C – 2%, up to 350 °C and up – 3%. For steam with pressure up to 50 MPa and temperature up to 475 °C – 2%, and with more great pressure and temperature – 3%.
Tolerance for thermal conductivity for liquids with temperatures from 25 to 200 °C and pressure up to 5 MPa is 1.5%, and with more great pressure and temperature up to 300 °C – 2%. For steam with temperature up to 550 °C with pressures up to 0.1 MPa – 1.5%, and with pressures up to 40 MPa – 3%. The sourced formulation for thermal conductivity calculate finite value in critical point, so in theory it must be infinite. So in area around critical point the tolerance can't be calculated.
Pic. 2. Relative tolerance for specific volume
For critical area (hatched triangle), bordered isohoric lines 0,0019 č 0,0069 m3/kg and isobaric line 30 MPa, showed relative tolerance of the pressure.
Pic. 3. Relative tolerance for specific isobaric heat capacity
Border of critical area (hatched triangle) – see. pic. 2
Pic. 4. Relative tolerance for sound velocity
Border of critical area (hatched triangle) – see. pic. 2
Pic. 5. Relative tolerance for pressure at saturation line