Investigating the impact of oxygen concentration on fire dynamics using numerical simulation with FDS

Abstract

The world is experiencing an increase in demand for medical facilities due to the worsening of environmental and political conditions leading to emergencies that could suddenly increase the patients count in hospitals. The extensive use and storage of oxygen in hospitals and violation of the fire safety management practices lead to the occurrence and worsening of fire accidents. Though many researchers documented the influence of O2 enrichment on fire dynamics, there are only limited studies present. This article attempts to investigate the effects of varying oxygen concentrations - 21% (v/v), 22% (v/v), and 23% (v/v) - on fire dynamics in a hospital environment using Fire Dynamic Simulator (FDS). The changes in Mass Loss Rate (MLR), Heat Release Rate (HRR), temperature profile, flash over occurrence and thermal intensity were reported and compared with varying oxygen concentration. The results show a significant increase in MLR and HRR with the increase in O2 concentration, which directly contributed to the earlier occurrence of flashover. For oxygen concentrations of 21% (v/v), 22% (v/v), and 23% (v/v), the highest temperatures achieved were 1395 °C, 1421 °C, and 1494 °C and the thermal intensity values were found to be 966 kW.m-2, 1027 kW.m-2, and 1074 kW.m-2, respectively. The variation in peak temperature and thermal intensity at 21% (v/v) and 23% (v/v) O2 concentration, is found to be 7.1% and 11%, respectively. The findings provide a valuable insight that the oxygen concentration in a fire can impact the fire dynamics. This study can aid in the development of effective fire safety management systems for hospital environments. In addition, the process industries have a key role to play in supporting hospitals to adopt proper approaches, drawing on lessons learned from managing flammable and explosive atmospheres in chemical processes. These simulation results will give better understanding to adopt relevant safety codes for the hospitals.