Validation of CFD fire model pressure predictions for modern residential style structures

Abstract

Controlled gas burner experiments were conducted in single- and two-story residential style structures instrumented with pressure transducers, thermocouples, and bi-directional probes throughout the structures. Exterior doors and window openings were vented in a controlled sequence to investigate the effect of the resulting flow paths on fire-induced flow dynamics and thermal conditions in the structures. The data collected in these experiments provides validation cases for the fire modeling community which currently lacks full-scale data from experiments in realistic residential style structures. The Fire Dynamics Simulator was used to model each scenario in a validation exercise that also investigated the sensitivity of the pressure predictions to the model parameters. The model was capable of predicting the qualitative changes in pressure measurements due to ventilation events as well as the apparent elevation of the neutral plane. Peak pressures were predicted to within 6% on average and quasi-steady static pressures were predicted to within 24% on average. The mean instantaneous error between the experimental pressures and those predicted with the “Localized Leakage” method was approximately 53% compared to 67% with the “Pressure Zone Leakage” method prior to the first ventilation event.