AbstractIn the past, real gas effects on the flame temperature were evaluated using the virial equation of state. Usually, the virial expansion was truncated after the third term. In this work the equation of state for dense gases proposed by Haar and Shenker is considered. The implementation developed for H2O, CO, CO2, H2, and N2 by Powell, Wilmot, Haar and Klein is used. The contribution of all minor species is assumed to be approximated by a Lennard‐Jones gas with ϵ/k = 100 K and σ = 3.0 Å. It is found that the more conventional approach is valid up to a loading density of 0.2 g/cm3. As density increases real gas effects cause the calculated flame temperature to decrease and the calculated pressure to increase. A computer program to perform the calculations has been devised for a personal computer.