5 Risk Assessment Techniques

Summary

This video covers the environmental risk assessment (ERA) process, emphasizing two key techniques: Fault Tree Analysis (FTA) and Event Tree Analysis (ETA). The ERA process is divided into three stages: pre-ERA, conducting the ERA, and post-ERA. FTA focuses on identifying hazards leading to a top event through a deductive approach, while ETA analyzes potential consequences from an initiating event using an inductive approach. Both methods can be applied qualitatively and quantitatively to assess risks and improve safety systems in environmental contexts. The lecture provides insights into the practical application of these techniques for thorough risk evaluation.

Takeaways

• 😀 The ERA process is divided into three main stages: pre-era, conducting the era, and post-era.
• 😀 Pre-era involves four steps: listing all processes on site, ranking them by risk level, selecting an ERA method, and estimating the manpower required.
• 😀 Conducting the ERA involves defining the objectives and scope, choosing the right team, and scheduling the ERA session.
• 😀 Post-era focuses on reporting the results, preparing a comprehensive report, and addressing action items for continual improvement.
• 😀 Fault Tree Analysis (FTA) uses a deductive approach, starting with the top event (disaster) and working backward to identify the hazards that contribute to it.
• 😀 FTA is effective for identifying and classifying basic causes, but it can become subjective and complex, leading to potential inconsistencies between different analyses.
• 😀 Event Tree Analysis (ETA) is the reverse of FTA; it starts with an initiating event and works forward to analyze potential outcomes based on that event's failure.
• 😀 In FTA, a common challenge is quantifying the probability and reliability of events, especially when data is scarce, such as in human factors.
• 😀 Both FTA and ETA can be used qualitatively and quantitatively, with ETA being particularly useful in reviewing safety systems and predicting the consequences of failures.
• 😀 Proper scoping is crucial for both FTA and ETA to avoid excessive detail and missed hazards or consequences, ensuring the analysis remains manageable and relevant.

Q & A

What are the three main stages of the Environmental Risk Assessment (ERA) process?

The three main stages of the ERA process are: 1) Pre-ERA, 2) Conducting the ERA, and 3) Post-ERA.

What is involved in the Pre-ERA stage of the risk assessment process?

The Pre-ERA stage involves four steps: identifying all processes on-site that require assessment, ranking these processes by risk level, selecting an appropriate ERA method, and estimating the manpower required for the assessment.

How does the Fault Tree Analysis (FTA) technique work?

Fault Tree Analysis is a deductive method that starts with identifying the top event (accident or disaster) and works backward to identify all the potential hazards or causes that could lead to this top event.

What are the advantages of using Fault Tree Analysis (FTA)?

The advantages of Fault Tree Analysis include clarity in identifying the top event and minimal cut sets, which help in pinpointing the key causes of accidents or disasters.

What are the disadvantages of using Fault Tree Analysis?

The disadvantages of Fault Tree Analysis are its subjectivity (leading to varying results depending on the assessor), potential complexity if not scoped well, and difficulty in quantifying certain events like human error without sufficient data.

What is the main focus of Event Tree Analysis (ETA)?

Event Tree Analysis focuses on identifying an initiating event and then working forward to determine the possible outcomes based on the failures or successes of safety systems in place.

How does Event Tree Analysis differ from Fault Tree Analysis?

Event Tree Analysis starts with an initiating event and works forward to identify potential outcomes, whereas Fault Tree Analysis starts with a top event and works backward to identify the causes of that event.

What are the advantages of using Event Tree Analysis (ETA)?

The advantages of Event Tree Analysis include its ability to assess the consequences of failures in safety systems, and its usefulness in evaluating safety and prevention systems.

What are the key disadvantages of Event Tree Analysis?

Event Tree Analysis can become extremely detailed and complex if not properly scoped, and the consequences may be uncertain if no proper research is done to identify all possible outcomes.

Why is it important to define the scope and boundaries in risk assessment techniques like Fault Tree Analysis?

Defining the scope and boundaries is critical in risk assessment techniques like Fault Tree Analysis to ensure the analysis remains focused, manageable, and relevant. Without proper boundaries, the analysis can become overly comprehensive, leading to unnecessary complexity.

What is the main purpose of the Post-ERA stage in the risk assessment process?

The Post-ERA stage involves reporting the findings from the ERA, presenting these findings to management for approval, and implementing corrective actions based on the findings to foster continual improvement.