A risk-based approach for structural assessment against fire considering escalation and passive fire protection (PFP) optimization

PurposeAccidental loadings such as fire constitute a great majority of potential and actual fatalities in both onshore and offshore installations. In order to prevent human loss and for a safe design of an asset, the risk of fire loading needs to be quantified, in terms of both probability/frequency and consequence aspects. In this paper the authors propose a novel risk-based approach for the assessment against accidental fire loading.Design/methodology/approachIn a conventional passive fire protection (PFP) analysis using ductility level analysis (DLA), fire loads are deterministically applied to a structure whose response is then analyzed. The initial PFP scheme is developed based on the analysis and then optimized. This approach is sometimes misinterpreted as a “risk-based” approach; however, it does not take into account the frequency aspect of the risk assessment. In a risk-based PFP analysis using DLA, fire scenarios are developed in a particular target zone. Then DLA is performed to determine the structural consequence. If personnel safety is of interest, the consequence of the structure is then linked to individual risk (IR) to determine fatalities. The amount of PFP to be applied on the structure is fully based on the risk that is produced by the fire scenarios in target zones.FindingsA new perspective on safe design of onshore/offshore structures for accidental loadings is outlined to estimate the associated risk to potential targets such as personnel as well as asset. The proposed assessment methodology will contribute toward identifying the mitigation measures and safety-critical procedures and equipment and toward a safer design.Originality/valueThis paper presents a new perspective in a safer design of onshore and offshore structures for a fire accidental loading based on risk calculation. Risk is defined as a combination of the frequency and consequence. An event frequency analysis is carried out to determine how often one should expect the event to occur. A consequence analysis is carried out to determine the severity levels of the event. In a risk-based consequence analysis, the severity levels are fully determined based on the risk associated with the event. The proposed novel risk-based assessment methodology against accidental fire loading contributes toward fully understanding the risk from an impact to personnel and to asset perspectives and leads toward safer and optimal design.