On Quantification of Error and Uncertainty in Two-zone Models used in Fire Safety Design

Abstract

The error in smoke transport models have mainly been analyzed with qualitative approaches till date. The results make it difficult to perform a quantitative assessment of the model error in fire safety design applications. Even if a model has a substantial model error, it can be a very useful tool, as long as the designer is aware of the errors and the uncertainties in the predictions. This paper presents a methodology to quantify the error in model predictions and the associated uncertainties with a statistical analysis of multiple scenarios. The knowledge of the model error can then be used to adjust future model predictions in order to take the error into account explicitly. This is done with an adjustment model valid for predictions during the whole pre-flashover phase of the fire scenario and not just at a single point in time. The approach taken is based on a quantitative comparison of model predictions and experimental measurements from several fire scenarios which constitute a scenario configuration. The application of the method is presented in a subsequent paper, where the model error in temperature predictions by the two-zone model CFAST 2.0 is analyzed.

Keywords

model uncertainty model error smoke transport model CFAST two-zone model fire safety design modeling temperature prediction

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