Fires may induce the thermal failure of LPG storage and transport vessels, leading to severe escalation scenarios. In the present study, an innovative CFD modeling approach was developed to investigate the thermal behavior of LPG tanks exposed to fires to support the prevention of catastrophic scenarios. For the first time, several data-sets were used to assess the model predictions considering different vessel scales, fire geometries and configurations. Comparison with experimental results demonstrates the predictive capabilities of the approach. The model allowed analyzing the role of different key phenomena, such as: the effect of free convection and thermal boundary layer forming in the near wall region, the thermal stratification, both in the liquid and the vapor phases, and the liquid thermal expansion. In addition, the influence of the vessel geometry on such phenomena was investigated. The results obtained may drive the design of emergency response, improving the safety of hazardous materials storage and transport systems.