Presents a numerical study on the applicability of employing Discrete Ordinates Method (DOM) for accounting the global radiative heat transfer of an enclosure fire in a two-compartment structure.Sensitivity studies considering the effect of S4,S6 and S8 approximations,corresponding to 24,48 and 80 fluxesrespectively,have also been carried out.The DOM employs Gaussian quadrature technique to approximate the Radiative Transfer Equation (RTE) by numerous principle radiation intensities,employing more radiation fluxes is expected to gives more accurate predictions.As the computational storage is limited by the currentlypersonal computer,the approximation order should be chosen carefully prior.The predicted temperatures from the three approximation orders are compared with measured data of the Nielsen and Fleischmann experiment .Contribution of soot particles to the radiation has also been considered by incorpaling Moss et al and Syed et al Model.The predicted temperatures form the three spproximations are almost overlapped.For weakly sooting flame ,similar to the LPG fuel used in the experiment,S6 approximation is demonstrated as an optimum choice for accounting the global radiative heat transfer in an enclosure fire.