The amount of heat radiated by flares is important for designing and locating flare systems. No methods are described in the literature for predicting radiation of enclosed ground flares. To investigate radiation of enclosed ground flares, a series of gas flares were simulated in this work by computational fluid dynamics (CFD). The radiation values derived by CFD simulation match the experimental data. For methane, propane, and butane flaring, the radiation flux of 15.77 kW/m(2) was attained only above the flare system, so radiation will not affect the integrity of the structures. The radiation flux at the ground level was below 1.58 kW/m(2), so this area is safe for personnel. For hydrogen, the radius of isopleth of radiation flux of 15.77 kW/m(2) can reach 33 m, so towers and elevated structures should not be located in these areas. The radius of isopleth of radiation flux of 6.31 kW/m(2) can reach 70 m, and on the ground the radius of isopleth of 1.58 kW/m(2) radiation flux can reach 120 m. Radiation decreases with increase in enclosed ground flare height, so the safe distance of enclosed ground flare can be reduced by increasing the ground flare height.