Hello Alvaro,
Here are all the formulas stuff, from Mike SS 5346.
Red top2bottom SS 6179
RemToDo for volunters to doctor
I did a quick check in the saturation region:
1. Remove unit system, otherwise Units don't match [like usual !!!]
2. By inspection, in saturation region the formulas aren't IAPWS-97
3. Thus my quick check p(125°C)=2.181 rather than 2.321
Quite not usable for Engineering Projects.
IMHO, useless attempting to doctor all those formulas.
Rather implement the original IAPWS in Smath.
Jean