Results from three models compared to full-scale tunnel fires tests

Information from full-scale fire tests are gathered and systemised. The knowledge from these tests is used as input to three different models, ranging from a simple spreadsheet model to advanced computational fluid dynamics (CFD) modelling, for calculating the temperature in the smoke layer. The deviation between the fire tests and the computed results is described and an evaluation of how this may influence the use of the models is discussed from the point of view of risk analysis.For experiments with small fires, i.e., one to five cars, one bus or one truck without cargo, the calculated temperature time curves from all models comply well with the measurements from the full-scale fire tests. For the larger fires, more deviation was found. The computational results were, however, on the same “order of severity” as the test fires, and thereby useful for hazard calculations. In contradiction to the general belief, the simplest models gave, in the same way as the CFD codes, results close to the values of severity recorded in the test fires with respect to HRR and smoke layer temperatures. The simple models may therefore be a good tool in risk analysis for not too complex tunnel structures.