Research On Crew Evacuation Safety Of Semi-Submersible Support Platform Under Fire

In the international and national process of exploiting far-sea marine resources,the deep water semi-submersible support platform is widely applied.The deep water semi-submersible support platform not only undertakes maintenance and repair functions of oil and gas exploration facilities,but also bears the residence function.However,due to the proximity of the diesel engine,generator,power system and other fire-causing energy conversion units to the cabin,the risk of fire is high.Besides,it is very likely to cause heavy casualties in the event of fire for its characteristics of being far away from the land,compact cabins,steep stairs,and narrow corridors.Therefore,research on crew evacuation safety of semi-submersible support platform under fire has great reference value for reducing the casualties.The research includes the study of smoke spread law of deep water semi-submersible support platform,the effect principle of fire and evacuation path on crew evacuation safety.Firstly,4 fire cases were established to investigate fire smoke spread law based on the most disadvantageous principles of fire scenario design.By comparing and analyzing fire simulation results of 4 cases,distribution law of upward spreading ability of smoke along stairwell and its influence on distribution of the extremum of temperature,visibility,CO volume fraction on the staircase of each deck were studied,the impact of the height of fire deck on the distribution law of required time of smoke filling the deck and on smoke spreading path was analyzed as well.The results show that when the distance between the stairwell and the fire room decreases,the upward spreading ability of smoke along the stairwell would be strengthened.The maximum temperature,the shortest time of visibility reaching critical condition,the maximum CO volume fraction of decks above fire deck are located in staircases with strong upward spreading ability of smoke.With the height of the fire deck increasing,it would take shorter time for the smoke to fill the decks above the fire deck and longer time for that below the fire deck.Secondly,crew evacuation safety assessment criteria was established according to relevant research to quantify effect of fire on crew evacuation safety,and evacuation results of fire and non-fire evacuation scenarios were compared and analyzed from evacuation outlets,evacuation time,congestion,use efficiency of exit based on the numerical results generated from Pyrosim and maritimeExodus.Effect principle of fire on crew evacuation was studied.The results show that effect of fire can cause number of available outlets reducing,total evacuation time increasing,congestion mitigating caused by arriving time discreteness enhancing,global use efficiency of exit raising,use efficiency of each-exit decreasing.Thirdly,evacuation path was planned on the basis of results of crew evacuation path under fire.Effect principle of evacuation path planning on crew evacuation was studied by comparing results of before and after planning evacuation path.The results show that the effect of fire on crew evacuation would be relieved by planning evacuation path,which could reduce total evacuation time,mitigate congestion and increase use efficiency of exit.The results can contribute to design of fire protection,planning of evacuation path and formulation of emergency plan when deep water semi-submersible support platform is on fire.