Simple functional representations for the thermophysical properties of gases at atmospheric pressure are given in this paper. Specific coefficients are provided for dry air and nitrogen. The functions are simple enough to use on desk calculators; yet their accuracy lies within that of the available data. The functions and FORTRAN subroutine, which are supplied, not only facilitate engineering calculations but add consistency and accuracy to them. The accuracy of the thermophysical property data, which are used in deriving the subject functions, is discussed.

A subroutine (ANSI Standard FORTRAN 77) is provided, which is written in a manner so that other gases and/or additional properties can be added without affecting current usage procedures. The computer code was provided in machine-readable form to the “Subprogram Computer Code Coordinator” designated by ASHRAE TC 1.5 on Computer Applications. The computer code was reviewed for conformity to standards for language, format, style, and level of documentation. Reviewers also compiled and executed the code prior to its publication.