Details

Need for high-rise buildings has increased to meet the modern urbanization needs. With the increase in technology and computational power, engineers are shifting towards performance-based design instead of prescription design for ensuring a higher level of fire safety in high-rise buildings with increased flexibility. In the present study, various methods of stairwell smoke extraction, as available in the National Building Code of India 2016 (NBC), are analysed and comparison is drawn between them. Computational modelling technique using the large eddy simulation method in Fire Dynamics Simulator (FDS) is employed to study fire scenarios in a model high-rise building. It was found that natural ventilation and cross ventilation in the stairwell is not fully effective for smoke extraction. Furthermore, the pressurisation of stairwell at a minimum differential pressure of 25-30 Pa seems to be effective only when all windows in the stairwell are closed. It was noticed that the maximum differential pressure in the stairwell is not defined in NBC. Case studies were also performed to see the effectiveness of single and multiple stairwell pressurisation techniques. A new technique by installing long smoke extraction duct along with pressurisation is also proposed and investigated which works effectively even when windows are open in the stairwell. In the end, conclusions from this study can be used for further improving the stairwell smoke extraction methods in NBC. The study was performed by focusing on the Indian context but the findings may generalize elsewhere too.