Quantitative Risk Assessments (QRA)
Quantitative Risk Analysis is proven as a valuable management tool in assessing the overall safety performance of a Chemical Process Industry.
Objective of QRA:
- To identify, quantify and assess the risk from the facility from the storage and handling of chemical products
- To identify, quantify and assess the risk to nearby facilities / installations.
- To suggest recommendations in order to reduce the risk to human life, assets, environment and business interruptions to as low as reasonably practicable.
Risk Analysis techniques provide advanced quantitative means to supplement other hazard identification, analysis, assessment, control and management methods to identify the potential for such incidents and to evaluate control strategies.
QRA is widely used in assessing the risk in Oil & Gas Installations especially refineries, tank farms, cross country pipelines, bottling plants, terminals etc.
Risk Assessment procedure:Hazard Identification is a critical step in Risk Analysis. Many aids are available, including What-if Analysis, Hazard and Operability (HAZOP) Studies, Failure Mode and Effects Analysis (FMEA), and Preliminary Hazard Analysis (PHA) etc.,
Assessment of risks is based on the consequences and likelihood
- Consequence Estimation is the methodology used to determine the potential for damage or injury from specific incidents. E.g.: Jet fire distances, BLEVE etc.,
- Likelihood assessment is the methodology used to estimate the frequency or probability of occurrence of an incident.
Software such as PHAST RISK MICRO 6.7, WHAZANv2.0, EFFECTS v2.0 are used to carry out the modelling of probable outcomes such as fire, explosion, vapour cloud explosion, BLEVE etc.
Risks are quantified using this study and ranked accordingly based on their severity and probability. Acceptability of the estimated risk must then be judged based upon criteria appropriate to the particular situation. Study report is used to understand the significance of existing control measures and to follow the measures continuously. Wherever possible, additional risk control measures are to be adopted to reduce the risk levels.