Definition:
Stated Risk is the theoretical or estimated level of risk determined during design phases based on assumptions, modeling, and initial hazard analysis.
In IEC 61511, this would align with the risk calculated through formal methods such as HAZOP, LOPA, or quantitative risk assessment, and documented in safety lifecycle activities. It is the “as analyzed” risk or the actual calculated risk.
Key Points:
- Calculated using hazard studies, risk graphs, LOPA, or QRA before operation.
- Assumes specific frequencies, consequences, protective layer performances, and human factors.
- Stated Risk may differ from Revealed Risk once the system operates and real data is collected.
Example:
A LOPA study during design estimates a fatality risk of 1E-4/year for an overpressure event. This becomes the Stated Risk.
See Also: revealed risk, revealed risk tolerance
Cited Source:
- CCPS Guidelines for Risk-Based Process Safety.