QRA (Quantitative Risk Assessment)
The main Objective of QRA is to make quantification of the risk involved from the operations in the chemical industries and processes. The evaluation is a four step process with Hazard Identification, Consequence analysis, Frequency estimation and Risk analysis/Risk assessment.
Identification of hazard involves identifying the probable scenarios or areas for possible loss of containment in the plant. The effects of the loss of containment in terms of damage distance, concentration, heat flux, over-pressure are assessed in consequence analysis. Taking into consideration of frequency of failure, the risk value is calculated and suggestion is offered in the report for reducing and mitigating the risk.
The scenario for risk analysis varies between Maximum Credible Loss Scenario (MCLS) and Worst Case Scenario and also a mixture of both.
Inputs of Risk Assessment are the inventory, hazardous properties of the chemicals involved, inherent design and engineered design aspects, engineering judgment and past history on accidents.
NSC conducts risk analysis using softwares such as ALOHA, SAVE II, DNV Phast etc.