In BowTiePro LOPA assessments, the overall consequence value represents the final calculated risk associated with a specific consequence after considering threats, controls, enabling factors, and condition modifiers.
This value helps users understand whether the remaining risk level is acceptable or if additional protection layers are required.
Viewing Consequence Values
To review consequence values:
- Open the LOPA module.
- Open an existing LOPA assessment.
- Navigate to the LOPA Details page.
- Scroll down to the Consequence section.
The consequence section displays the consequence linked to the selected threat and top event.
Understanding How Consequence Values Are Determined
The final consequence value is influenced by several elements within the LOPA assessment, including:
- Threat frequency
- Enabling factors
- Independent protection layers (IPLs)
- Condition modifiers
- Control PFD values
- Consequence controls
BowTiePro combines these values to determine the remaining risk level after safeguards are applied.
Reviewing Threat and Consequence Controls
Controls directly affect the calculated risk value.
Threat controls reduce the likelihood of the event occurring, while consequence controls reduce the severity or impact after the event occurs.
Each control can include:
- PFD (Probability of Failure on Demand)
- Justification details
- Inclusion or exclusion from calculations
Understanding the Final Result
The overall consequence value helps users determine whether:
- Existing safeguards are sufficient
- Additional IPLs are needed
- The scenario meets acceptable risk criteria
- SIL requirements may be necessary
The value is continuously updated based on the inputs configured throughout the assessment.
Viewing Consequences in the LOPA Diagram
Users can also visually review consequences directly within the LOPA diagram.
The diagram provides a simplified visual representation of:
- Threats
- Controls
- Top events
- Consequences
- Relationships between protection layers
This helps users better understand how each protection layer contributes to overall risk reduction.
Best Practices
When reviewing overall consequence values:
- Ensure threat frequencies are accurate
- Verify all IPLs are properly configured
- Review PFD values carefully
- Add clear justifications for controls
- Confirm condition modifiers reflect realistic scenarios
- Regularly update assessments when operational changes occur
Accurate configuration ensures more reliable LOPA calculations and better risk management decisions.