Every year, high numbers of firefighters are injured at fire incidents. A primary cause of moderate to severe injury can be linked to the protective garments worn by firefighters and understanding the limits of these protective garments is crucial for their safety. It would be substantially advantageous to firefighter safety if their available safe escape time is included in building design. To do this, the heat protective performance of firefighter garments needs to be translated into a tenable time. In this study, the minimum Thermal Protective Performance (TPP) rating of firefighter garments was investigated and found to compare well to known firefighter environments. This TPP rating was then used to further process the heat flux results from a CFD based fire model to determine an available safe escape time for firefighters. The probability of firefighters being injured was required in this study. It was used to assess the accuracy of the fire model in estimating the critical heat flux required to prevent a safe available escape time.