Quantitative Risk Assessment
This is the quantification of risk arises from the facility. Risk is a combined effect of consequences and probability of the event and is expressed in terms of risk/ avg year. The risk is benchmarked against the risk acceptance criteria of the country and accordingly the action is taken to mitigate the risk.
The techniques used for risk prediction within the QRA have inherent uncertainties associated with them due to the necessary simplifications required. In addition, QRA incorporates a certain amount of subjective engineering judgment and the results are subjected to levels of uncertainty. For this reason, the results should not be used as the sole basis for decision making and should not drive deviations from sound engineering practice. The results should be used as a tool to aid engineering judgment and, if used in this way, can provide valuable information during the decision making process.
QRA technique can be applied to any industry where toxic or flammable material is being used, handled, stored or transported.
Dispersion / Consequence Analysis
The study includes assessment of severity / impact of the hazards / undesired event that may take place in the facility. The consequences are given in the terms of flammable / toxic gas dispersion (ppm), thermal radiation (kW/m2) and explosion overpressure (psi or barg) distances.
Likelihood Estimation
This is a process of calculating or estimating the frequency of failure for a specified risk section or facility. Fault tree, event tree or failure generic data base are used in estimation of likelihood.
Qualitative Risk Assessment
The risks which cannot be quantified are categorised under qualitative risk assessment. In this the risk is expressed in terms of low, medium or high risk levels by benchmarking against Risk Matrix.