Transcript No Slide Title

Quantitative
Risk Assessment
What is QRA
• Systematic methodology to assess risks
associated any installation
– Taking into consideration all forms of hazards
– Uses design information and historical data to
estimate frequency of failure
– Uses modelling software to assess consequence
• Where/when is QRA needed
– CIMAH 1989 – part of CIMAH safety report
– EQA 1985 – a section under EIA
Definition
Risk = Severity x Likelihood
• Extent of Damage
• Fatality
• Injuries
• Losses
• Likelihood of event
• Based of failure frequency of
process components
• Analysis based on design and
modeling equations
• Analysis based on
manufacturer’s and historical
data
Methodology
Hazard Identification
Frequency Analysis
Risk Estimation and
Evaluation
Risk Management
Consequence
Analysis
Hazard Identification
• Purpose: to identify plausible hazard
conditions
• Methods
– Check-list, Preliminary Hazard Review, HAZID,
HAZOP etc.
– Unstructured brainstorming?
Further Details
Frequency Analysis
• Sometimes referred to as Hazard Analysis
• Purpose: To estimate the likelihood for a
hazard scenario to occur
• Methods
– Event-Tree Analysis
– Fault-Tree Analysis
Further Details
Consequence Analysis
• Purpose: To assess the extent of damage
• Typical Hazard
• Toxic Release, Fire and Explosion
• Modelling of hazard scenario
– Toxic Release: Source (Release) Model, Dispersion
– Fire and explosion: Source Model, Fire and Explosion, Heat
Dispersion
– Fatality Assessment: Probit Analysis
– Nonfatal Consequence: Skin-burn, Property damage
Further Details
Risk Estimation and Evaluation
• Purpose: To assess Risk and Make Safety
Judgment
• Methods
– Individual Risk: IRPA, LSIR
– Societal Risk
• Tolerability Criteria
Further Details
Risk Management
• Propose: to propose mitigating measure to
reduce the potential impact of the hazard and
possibly reduce the risk level
• Method
– Safe Work Procedure at every project stages
– Emergency Response Management
– Emergency Response Procedure