Quantitative Risk Assessment

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Quantitative Risk Assessment
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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

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Definition

• Risk Severity x Likelihood

• Extent of Damage
• Fatality
• Injuries
• Losses
• Analysis based on design and modeling equations

• Likelihood of event
• Based of failure frequency of process components
• Analysis based on manufacturers and historical
  data

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Methodology
Hazard Identification
Consequence Analysis
Frequency Analysis
Risk Estimation and Evaluation
Risk Management
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Hazard Identification

• Purpose to identify plausible hazard conditions
• Methods
• Check-list, Preliminary Hazard Review, HAZID,
  HAZOP etc.
• Unstructured brainstorming?

Further Details
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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
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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
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Risk Estimation and Evaluation

• Purpose To assess Risk and Make Safety Judgment
• Methods
• Individual Risk IRPA, LSIR
• Societal Risk
• Tolerability Criteria

Further Details
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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