A TRI methodology developed previously for hydrogen jet flames is applied to carbon monoxide and methane jet flames. The paper demonstrates that the TRI methodology can accurately predict the spectral intensity distribution and heat flux distribution across a range of jet flames. A p probability density function (PDF) together with Reynolds averaging of the instantaneous properties along rays traversing the flames is used to prescribe the instantaneous incident intensity. Unlike most other studies in this area the model is used to predict the heat flux distribution as well as the spectral intensity. The underlying reason why hydrogen jet flames exhibit strong TRI compared to carbon monoxide and methane is also considered and shown to be a complex phenomena deserving of more research. The paper demonstrates that for the data available the heat flux distribution tends to be more sensitive to TRI than the spectral intensity distribution. Another interesting finding is that TRI can reduce as well as enhance the spectral intensity. (C) 2014 Elsevier Ltd. All rights reserved.