Floating Liquefied Natural Gas (FLNG) units have been under development for decades. They are nowbecoming a reality, combining the design and installation of LNG units with a traditional “FPSO”. SinceFLNG facilities handle large flammable gas quantities in a relatively small and congested environmentcompared to onshore LNG plants, the explosion risk is expected to be higher than some other offshorefloating facilities. As a consequence the intensity of the resulting blast loads on the unit can be moresevere even if the explosion likelihood is considered low in the design through a frequency analysis.Even if prevention and mitigation measures are implemented to reduce the risk to ALARP (As Low AsReasonably Practicable), Safety Critical Elements (SCE), such as main equipment and structures, shall bedesigned to withstand the blast event. Since the explosion events are very specific (high intensity and shortduration), the common design rules and tools should be updated to take into account this accidental event.In addition, the associated performance criteria for SCEs should be also modified. Finally the entire designshall comply with safety objectives (personnel protection, prevention of escalation).This paper focuses on the philosophy of design against a blast event. It will review the critical functionsof the unit that must be maintained during emergency evacuation in order to protect people and, identifythe key parameters governing the explosion strength on FLNG. It will show that the derivation of effectiveexplosion loads on structures and equipment based on computational fluid dynamics simulations is notstraightforward and requires expertise both in explosion modeling and explosion response. In a secondpart the paper will show how all the engineering disciplines in Technip individually apply these blast loadsinto their design through non-linear finite element analyses. Finally, it will highlight the interface betweenthe engineering disciplines and how a consistent demonstration through the design can be achieved inorder to fulfill the safety goals, taking engineering further.
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