Sulfur hexafluoride (SF6) is the most common medium used in HVAC circuit breakers. Unfortunately it has a Global Warming Potential (GWP) 23000 times higher than CO2 and it is consequently listed in the Kyoto protocol as greenhouse gas. For this reason it is an urgent task to find possible suitable substitutes. Manufacturers need to study and compare with SF6 the current interruption performances of another gas using numeric computational methods. This study provides 5 fluoronitrile-CO2 mixtures thermodynamic and transport tables which are essential for the computation.