Overview
EN ISO 19901-2:2026 defines the seismic design requirements for offshore structures, focusing on the oil and gas sector, including lower carbon and renewable offshore energy assets. Developed by CEN in collaboration with ISO Technical Committee 67, this standard provides a harmonized framework for assessing and designing structures to withstand earthquake-induced ground motions and related geological hazards such as liquefaction, tsunamis, and mud volcanoes. It also delivers guidance for probabilistic seismic hazard analysis in high-seismicity areas or for facilities with a high consequence level, supporting lifecycle safety, asset integrity, and environmental protection.
Key Topics
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Seismic Hazard Assessment:
- Emphasis on ground motions, soil liquefaction, fault displacements, submarine landslides, tsunamis, and mud volcanoes.
- Requirements for both fixed and floating offshore structures to ensure robust seismic resilience.
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Performance Objectives and Limit States:
- Detailed procedures to establish and verify performance objectives, including near-collapse (NC) and damage limitation (DL) limit states.
- Categorization of structural damage and clear criteria for acceptable risks regarding life safety, business continuity, and environmental protection.
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Site-Specific Analysis:
- Guidance on conducting site-specific probabilistic seismic hazard analysis (PSHA) and deterministic seismic hazard analysis (DSHA).
- Consideration of local soil conditions and site response for accurate prediction of seismic impacts.
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Classification and Risk Management:
- System for assigning seismic risk categories (SRC) based on structural consequence level and seismic zone.
- Framework to align risk-tolerance with operational, regulatory, and safety expectations.
Applications
EN ISO 19901-2:2026 serves a critical role in the safe and effective development of offshore energy projects. Its applications include:
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Offshore Oil and Gas Platforms:
- Ensures platforms are designed to withstand seismic loads, minimizing risk of collapse, loss of containment, or prolonged downtime.
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Renewable Offshore Energy Structures:
- Expands on the previous edition by encompassing requirements for offshore wind farms and associated infrastructure.
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Floating Structures and Mobile Units:
- Addresses seismic design considerations unique to floating platforms and mobile offshore units, ensuring continued safety and operability following seismic events.
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Risk Evaluation for High-Value or High-Hazard Installations:
- Provides a rigorous, quantifiable methodology for seismic risk assessment of facilities in critical or environmentally sensitive areas.
Organizations implementing EN ISO 19901-2:2026 benefit from reduced operational risk, enhanced compliance with regulatory frameworks, and improved stakeholder confidence in the resilience and reliability of their offshore assets.
Related Standards
- ISO 19900: General requirements for offshore structures - forms the foundation for structure-specific standards.
- ISO 19902: Fixed steel offshore structures - complementary seismic provisions for steel platforms.
- ISO 19903: Concrete offshore structures - additional detail for concrete-based assets.
- ISO 19904: Floating offshore structures - further seismic requirements for floaters.
- ISO 19905: Mobile offshore units - seismic assessment guidance for non-permanent installations.
- ISO 19906: Arctic offshore structures - addresses unique seismic and environmental challenges in cold regions.
Practical Value
Adopting EN ISO 19901-2:2026 enables organizations to:
- Improve structural safety, minimizing seismic risks to personnel, environment, and infrastructure.
- Achieve compliance with international and regional regulations for offshore seismic design.
- Utilize updated seismic hazard mapping and industry-proven risk management approaches.
- Enhance project design flexibility without compromising on seismic integrity or innovation.
EN ISO 19901-2:2026 is an essential reference for engineers, designers, risk managers, and regulators involved in the lifecycle of offshore energy assets, ensuring that structures remain safe and functional even in the most challenging seismic environments.
