A new approach to smoke control systems in complex atria

Large occupied spaces such as the atria can have additional internal elements like balconies, stairs, or decorations. Unfortunately, detailed design rules for smoke management systems are lacking in these large contemporary spaces. A series of smoke tests and CFD simulations were conducted to address this shortfall. The project’s first step was realised with full-scale hot smoke tests in Smoke Laboratory, which allowed the observation of a significant influence of the suspended balconies on smoke mass production. CFD simulations confirmed the preliminary observations and were used to evaluate this phenomenon quantitatively. This proved that the wider the balcony, the greater the mass increase. The same fire scenarios were examined with theoretical NFPA 92 correlations dedicated to axisymmetric and balcony spill plumes. They showed that using the standard axisymmetric plume correlation in a complex atrium could lead to a strong underprediction of the required smoke control system parameters. A proposed adapted balcony spill plume correlation can improve the smoke mase calculations. This study demonstrates that existing standards like NFPA 92 NFPA 204, or BS 7346-4. Do not cover the need for smoke control systems in complex and irregular atria solutions, which often appear in modern buildings. It has been proven that the obstructions in the atrium space significantly influence the smoke mass production. As a consequence, using the original axisymmetric plume correlation in a complex atrium could lead to a strong underprediction of smoke control system requirements. The authors proposed a new correlation for the approach to smoke control systems parameters approach at the design process.