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: RS= 1 – [(1 – RA)(1 – RB)]

• series,
  

  • Formula: RS = RA × RB

• 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