Boiler tube failures occur in steam generation boilers due to sub critical Short Term Overheating (STO). In general, sub-critical STO occurs when design parameters are often marginally and critically discounted. This leads to frequent failures of the boilers that affect the sustainability of power generation. A commercial Computational Fluid Dynamics (CFD) software, ANSYS Fluent 19.0® (multiphase flow), was used to successfully predict the regimes where the phase boundary of energy transfer occurs. Significant heat transfer parameters were numerically established to determine recommendations for preventing the failures of these tubes under their current operating environments. They are limited to a single horizontal carbon steel water tube. Research is continuous with the aim of establishing an emphirical model to predict the in-service remaining useful life of these boiler tubes when operated within a certain massflow and temperature range.