Reliability Methods for Offshore Structural Integrity (ISO 19901-9 Review)
Offshore structures are increasingly operated beyond their original design life. The revised international standard ISO 19901-9 introduces explicit reliability- and risk-based methods for managing their structural integrity – this project provides an independent scientific review of these methods.
Background
The second edition of ISO 19901-9 (structural integrity management of offshore structures) introduces a hierarchy of assessment levels, up to fully probabilistic and risk-based assessment built on hazard and fragility curves, target reliability levels and risk-acceptance criteria. These methods are powerful, but their assumptions, approximations and acceptance criteria have far-reaching consequences for how ageing offshore infrastructure is assessed and operated.
What we do
- An independent technical review of the reliability- and risk-based assessment methods of the draft standard, from the perspective of structural reliability theory and international principles documents.
- Systematic examination of the hazard/fragility-curve formulation: its assumptions, its consistency across assessment levels, and the interpretation of the target reliability levels and acceptance criteria.
- A technical report supporting the Norwegian and Danish members of the responsible ISO committee (ISO/TC 67/SC 7) in the international standardization process.
Impact
Extending the safe operating life of existing offshore structures avoids unnecessary decommissioning and replacement. A scientifically sound and transparent assessment standard is the key that makes such life extension defensible – for regulators, operators and society.
