Do you have the steam tables in Excel form? You could use a READEXCEL function to pull the tables in. Alternately you could embed the spreadsheet as an Excel component. From there, your problem is one of extraction and interpolation. Depending on how much of the data in a steam table you actually need, the overhead might not be too large.
If you have a functioning steam table lookup spreadsheet, the embedded sheet might be your best option. You could pass your constraints to the spreadsheet and extract your resultant values. I found a steam table from LearnChemE.com and used it as a starting point. (attached)
Bob
