This study is related to consequence analyses of accidental LNG explosions are often carried out to assess the long-term consequence and vulnerability of the gas transportation pipeline system. In these consequence analyses, it's indispensable to adequately predict the thermal radiation intensity of LNG explosive fireball process in open space. In this study, a new empirical theoretical method for explosive fireball in open space was developed and a full-scale experiment involving LNG explosion in transmission pipeline was carried out. Significant theoretical prediction, experimental testing and quantitative analysis with numerical simulation commenced leading to a better understanding of the thermal radiation hazard from LNG explosive fireball. The parameters of LNG explosive fireball were compared and verified with the full-scale experimental data, and it found that the theoretical predictions agreed well with experimental data. To demonstrate and verify the probability and potential hazard range to humans and surroundings, hazard analysis of this case was performed on the PHAST simulator. Based on the corresponding thermal radiation harm criterion, it is concluded that a near 100% fatality is expected in the range of within 190 m and there is no any harm when people stay beyond the scope with the ellipse diameter of 720 m. (C)2017 Elsevier Ltd. All rights reserved.