Evaluation of the burning rate based fire curve calculation method for the case of full scale railcar fire

초록

Two different approaches can be used for the analysis of the solid material burning mechanism in fire dynamics simulation. One way is based on the assumption of specific burning rate of materials with the HRRPUA (heat release rate per unit area) and burning area decision methodology. The other method uses the values of heat of combustion and heat of reaction for microscopic material pyrolysis analysis. In this study, the fire curve calculations by HRRPUA model and Pyrolysis model were compared with that of the full-scale railcar fire test. Fire size represented by the heat release rate from the railcar fire was measured according to the ignition scenario in EN 45545-1. Surface temperatures of every part of the interior were measured for the ignition decision for the supplementation of video films of flame spreading performance at the test. The HRRPUA of interior materials was prepared with ISO 5660-1 small-scale cone-calorimeter test to create a specific burning rate ramp curve. Additionally, the burning surface area could be decided directly from the measured temperatures and from FDS (fire dynamics simulator) model calculation by ignition temperature inputs to the interior materials. For the pyrolysis model case, more sophisticated material property and design inputs are needed to get the same degree of accuracy. This study is expected to contribute to the development of a simple method for the fire curve estimation of railcars without expensive fire tests.