Thermal radiation, although considered an important mode of heat transfer in high temperature conditions, often is neglected in re modeling, mainly because of the complex physics involved. This study provides modelers with guidance on the engineering treatment of radiation transfer. Two widely used radiation models, the discrete transfer and the six-ux models, are reviewed and their performance is assessed in a benchmark re case. The models are compared in terms of computational ef ciency, ease of application, and predictive accuracy , and their range of validity is delineated, for single compartment re cases. The results demonstrat e that the simple six-ux model suf ces for small compartment res, up to 100 kW. For higher heat release rates, where the six-ux model breaks down, the discrete transfer provides suf cient accuracy, under certain conditions. INTROD UCTIONThermal radiation can be an important mode of heat transfer in processes involving high temperatures and for that reason the computational analysis of thermal radiation transfer in enclosure ¢re modeling is essential. Predicting possible secondary ignition, for example, because of thermal radiation, is particularly important in ¢re safety engineering. Another case is the blocking of radiant heat by a water spray or mist, as an important mechanism in ¢re extinction. In many numerical simulations of ¢re behavior, the modeling of radiative transfer often is neglected, mainly because it involves complex mathematics, high computation cost, and great uncertainty concerning the optical properties of the participating media and surfaces. Nevertheless, ignoring radiative transfer may introduce signi¢-cant errors in the overall predictions.Most of the major developments in the engineering treatment of radiative transfer have been driven by the need for accurate predictions in industrial furnaces. Consequently, there have been numerous evaluations of radiation models for furnaces. For ¢re modeling, on the other hand, very few studies have been done.