Quantitative Risk Analysis (QRA)

The objective of this Quantitative Risk Analysis are :

The Purpose of QRA study are:

Quantitative risk assessment (QRA) is a systematic approach utilized to analyze the potential risks associated with hazardous activities. The aim is to provide a rational evaluation of the risks significance, which can be used as input for decision-making processes. The QRA process is presented below in Figure

The following key activities are performed during QRA:

The hazardous scenarios considered in the risk analysis for the facility covered under scope of the project will be identified based on the properties of the materials handled and the identification of the potential hazards in the systems which could lead to loss of containment events.

The results of hazard identification is a list of credible accident scenarios (CASs) that may occur at the facility, which could lead to event such as, jet, pool, flash fires, vapour cloud explosion and toxic cloud dispersion. Natural calamity such as earthquake, sandstorms and lightning are not considered for frequency assessment. However, impact of these could lead to leak or rupture which are considered in consequence analysis.

In any risk assessment study, it is required to make certain assumptions. The assumptions can be in the development of a rule set and use of judgment data. In this study also, the assumptions will be made to enable the modelling of complex systems through simplification and approximations. This is a necessary part of the assessment and the quality of the assumptions influences the outcome, as well as the level of uncertainty in the assessment.

The evaluation of the impact of identified loss of containment (LOC) scenarios on individuals will be carried out through consequence modelling. The analysis will focus on assessing the effect distances of these scenarios. The project will undertake consequence analyses encompassing the subsequent activities:

The consequence modeling will be performed using DNV PHAST software.

The hazard consequence assessment based on the consequence modeling includes

After identifying probable release situations, international standard database is used to assess failure frequencies. The procedure for conducting the frequency analysis is as follows:

Generic Failure data will be applied if site specific or company data is not available. In general, OGP Risk Assessment Data Directory, Process Release Frequencies shall be used. Risk assessment will be undertaken to evaluate the risk associated with the project facility. The risk shall be typically presented as Individual Risk and Societal Risk.

Risk evaluation involves the evaluation of the individual risk results against the Risk Acceptance Criteria to determine whether the risks are broadly acceptable, ALARP or unacceptable. Sensitivity Analysis will be carried out on assumptions made to model inputs. Comparison of evaluated risk in the sensitivity analysis with acceptance criteria will be carried out.

As per Risk assessment, if calculated risks fall within the unacceptable range, it becomes imperative to implement risk mitigation measures to reduce risks to a level that is tolerable or as low as reasonably practicable (ALARP). It is imperative to identify all feasible measures for mitigating risks, including novel interventions or enhancements to pre-existing interventions that have been implemented or installed.

Cost Benefit Analysis (CBA) is a technique for comparing the costs and benefits of additional safety measures by comparing the cost of implementing the measure with the benefit of the measure, in terms of the risk-factored cost of accidents it will avert.

Cost-benefit analysis (CBA) serves the purpose of evaluating whether the advantages of a particular course of action exceeds its drawbacks, thereby determining the suitability of implementing said course of action.

The CBA approach requires monetary evaluation of the risks or the monetary evaluation of the loss of life. The evaluation of measures to avert loss of life requires ‘Valuation of life’ criterion and the ‘Valuation of life’ shall be used for the study.

The comprehensive report will encompass the methodology, study findings, and recommendations derived from the QRA study. The report will be structured into distinct sections, which are outlined as follows.

The following are the deliverables for QRA study: