[en] A thermophysical property correlation package of hydrogen, carbon monoxide, carbon dioxide and methane has been constructed from a critical evaluation of theoretical or empirical correlations available in the literature. The properties include density, isobaric specific heat, viscosity and thermal conductivity. Selected package correlations are summarized below: (1) For density, Peng-Robinson-Redlich-Kwong equation of state, (2) for specific heat, an expression from thermodynamic theory with the van der Waals equation of state and (3) for viscosity and thermal conductivity, generalized relationships by the use of dimensional analysis that were developed by G. Thodos group. From a comparative evaluation of the package correlations with measurements and selected values available, it has been concluded that except for specific heat these correlations are predictable with an acceptable accuracy. (author)