IA5 – Summary

1. Sources of Information Used in Identifying Hazards and Assessing Risk

• Accident/Incident and Ill-Health Data and Rates
  • incidence rate,
  • frequency rate,
  • severity rate and
  • prevalence rate.
• Internal & External Information Sources

• Uses and Limitations of Information Sources
  • Internal
    • Incidence are rear events
  • External
    • Different industries
    • different multiplier
    • different terms of reference (definitions)
    • Overtime or part-time workers are not taken into account
    • The figures may be for workers only
    • Culture differences
    • Different risk levels
    • different risk management arrangements

2. Hazard Identification Techniques

• Hazard Detection Techniques
  • task analysis,
  • checklists – covers the key issues to be monitored is developed to ensure a consistent and comprehensive approach to checking all the safety elements to be covered during an inspection.
  • observations and
  • incident reports.
• Importance of Worker Input

3. Assessment and Evaluation of Risk

• Key Steps in a Risk Assessment
  • Hazard identification.
  • Identify who is at risk.
  • Estimation, evaluation of risk and identifying precautions.
  • Record significant findings and implement.
  • Review the assessment.
• Use and Limitation of Generic, Specific and Dynamic Risk Assessments
• Limitations of Risk Assessment Processes
• Temporary and Non-Routine Situations
• Consideration of Long-Term Hazards to Health
• Types of Risk Assessment
  • Generic – apply to commonly identified hazards and set out the associated control measures and precautions.
  • Specific – apply to a particular work activity and the persons associated with it.
  • Dynamic – apply to work activities that involve changing environments and require quick mental assessments to manage risks.
  • Qualitative – risks are represented by simple word descriptors.
    • – Risk = Probability (or Frequency) × Consequence (or Harm or Severity).
    • – Probability is the chance that a given event will take place.
    • – Severity of risk is the outcome.
  • Semi-quantitative – results represented by qualitative and quantitative descriptions. In some the risk is expressed as a number which indicates rank and not an absolute value.
  • Quantitative – risks are represented by the frequency or probability of a specified level of harm, from a specified activity.
• Organizational Arrangements for an Effective Risk Assessment Programme
  • Plan – what you want to achieve, who will be responsible for what, how you will achieve your aims, and how you will measure your success.
  • Do – identify your risk profile, organise your activities to deliver your plan.
  • Check – measure your performance, assess how well the risks are being controlled and investigate the causes of  accidents, incidents or near misses.
  • Act – review your performance and take action on lessons learned, including from audit and inspection reports. Once hazards have been identified, the risk they pose needs to be assessed and prioritised.
• Acceptability/Tolerability of Risk

4. Systems Failures and System Reliability

• Meaning of the Term ‘System’
  • complicated interactions between processes and that failure of the system may need detailed investigation to discover the causes by adopting both holistic and reductionist approaches.
• Principles of System Failure Analysis
• Using Calculations in the Assessment of System Reliability
  • parallel,
    • Formula: R_S= 1 – [(1 – R_A)(1 – R_B)]
  • series,
    • Formula: R_S = R_A × R_B
  • mixed systems
    • Formula: Calculate all Parellel Systems, then treat system as a chain of Series Systems.
• Methods for Improving System Reliability, by using
  • reliable components,
  • quality assurance,
  • parallel redundancy,
  • standby systems,
  • minimizing failures to danger,
  • planned preventive maintenance and
  • minimizing human error
    • The ‘right’ person is doing the ‘right’ job.
    • The individual has adequate training and instruction.
    • The individual receives appropriate rest breaks.
    • The man-machine interface is ergonomically suitable.
    • The working environment is comfortable, e.g. noise, lighting, heating, etc.

5. Failure Tracing Methodologies

• A Guide to Basic Probability
  • Probability is the chance something will happen.
  • Frequency takes account of the exposure.
  • To calculate the probability of two or more independent events occurring, we Multiply the probabilities.
  • To calculate probability of one event OR another, we Add the probabilities of the two separate events.
  • To calculate the probability of a probable event happening at certain frequency to cause harm we Multiply Probability by Frequency.
• Principles and Techniques of Failure Tracing Methods in the Assessment of Risk
  • HAZOP
    • Keywords:
      • NO or NOT – Negation of intention, e.g. no flow.
      • MORE – Quantitative increase, e.g. high pressure.
      • LESS – Quantitative decrease, e.g. low temperature.
      • AS WELL AS – Qualitative increase, e.g. impurity present.
      • PART OF – Qualitative decrease, e.g. only one of two components present.
      • REVERSE – Logical opposite of intention, e.g. backflow.
      • OTHER THAN – Complete substitution, e.g. flow of wrong material.
  • Fault Tree Analysis
    • Keywords:
      • Event. To Understand: Divide 1 to contributing factors’ probability calculation result.
      • AND Gate – all events need to be present at the same time to allow the Top Event. – Most Efficient. To Calculate: Multiply Probabilities
      • OR Gate – one of the events need to be present at the same time to allow the Top Event. To Calculate: Add  Probabilities.
      • Basic Fault
  • Event Tree Analysis

Appendix 1. Support Links

• IA5 Questions & Answers