Numerical modelling of changes of pressure inside the protected room during fighting the fire using carbon dioxide

Purpose This paper aims to study and assess a new approach for prediction of changes of pressure during gas discharge inside the room protected by fixed gaseous extinguishing system by computational fluid dynamics (CFD) simulations. Design/methodology/approach The research program consisted of two stages. The first stage was dedicated to the experimental measurements of pressure changes during extinguishing gas discharge into the test chamber in a real scale (70 m3), for two relief openings that differ in their area. The next step was about performing CFD simulations forecasting pressure changes during gas discharge into the numerically represented test chamber. Estimation of the correctness and usefulness of the CFD model was based on a comparison of the CFD results with standard calculations and experimental measurements. Findings Numerical modelling of pressure changes during the carbon dioxide discharge was very close to the experiment. The obtained results had sufficient accuracy (in most cases relative error <15%), while the standard approach predicted pressure changes with an average relative error over 36% and did not estimate the decrease of pressure at all. Originality/value Conducted research confirms the viability of the new approach in modelling the pressure changes and indicates additional benefits of the numerical analyses in the determination of the fire safety of protected premises.