The Development of an Integrated Quantitative Risk Analysis System and Its Application on a Complex Disaster with Toxic, Fire and Explosion Disasters

The purpose of this research is to establish an integrated method which can assess the risk of the toxic and the chemical disaster within a three-dimensional space.  This research employs Fire Dynamics Simulator (FDS) and Flame Acceleration Simulator (FLACS), both belong to the Computational Fluid Dynamics (CFD) fire and explosion simulation software, to analyze the consequences of personnel injury under fire, explosion and toxic gas release within a semiconductor cleanroom.  Furthermore, an Integrated Quantitative Risk Analysis System (IQRAS) programmed in C# language is used to assess the Individual Risk (IR) of the personnel.   Additionally, this study designs and simulates the following cases: the isopropanol (IPA) burning, the hydrogen explosion event and the ammonia dispersion event.  Besides assessing the impact of the hazard factors on the equipment and the personnel of a cleanroom, the IQRAS also calculates the maximum physical effect, the death probability and the individual risk of seven types of hazardous factors (thermal radiation of fire, carbon monoxide, smoke, pressure, impulse pressure, thermal radiation of explosion and toxic gas dispersion).  This study outputs the dynamic images, the iso-surface plots and the transection plots via the graphical software (including SmokeView, FlowVis and MatFor) to implement the consequence and the risk analysis of the simulation results.  Using IQRAS one can integrate two grid systems of different CFD software successfully and can fully display the implementing procedures of the integrated 3D risk analysis techniques.  After comparing all the results it is worth mentioning that the integrated individual risk of the cleanroom is between 1.71×10^-9 (person/year) to 3.21×10^-5 (person/year), if the process has no protection or all its mitigation measures fail.  For further research and for as long as the simulation case is implemented via the CFD software (FDS or FLACS), its risk value can be calculated by using the method developed in this study.  The results of this research can probably give to the policy makers and to the researchers a better reference basis for hazardous risk assessment.

Keywords: Integrated Quantitative Risk Analysis System (IQRAS), Fire Dynamics Simulator (FDS), Flame Acceleration Simulator (FLACS), fire and explosion, toxic gas, risk assessment.