ISO 19901-2:2026

Overview

ISO 19901-2:2026 specifies the requirements for the seismic design and assessment of offshore structures. Published by the International Organization for Standardization (ISO), this standard outlines best practices to ensure structural safety, reliability, and resilience of offshore installations-both fixed and floating-in regions subject to earthquake-induced ground motions and other geologically induced hazards. The standard covers site-specific probabilistic seismic hazard analysis, addresses secondary hazards such as liquefaction, slope instability, fault displacement, tsunamis, and mud volcanoes, and includes essential recommendations for facilities with high consequence levels and those located in seismically active offshore areas.

Key Topics

• Seismic Hazard Assessment: Guidance on identifying, quantifying, and combining uncertainties in earthquake activity through probabilistic and deterministic seismic hazard analyses (PSHA/DSHA).
• Structural Design Requirements: Criteria for the design and verification of offshore structures to withstand seismic loading, including limit state checks for collapse and damage.
• Performance Objectives and Categories:
  • Life safety, environmental protection, and business continuity performance objectives.
  • Assignment of structures to seismic risk categories (SRC) based on consequence levels and seismic hazard zones.
• Special Considerations for Floating Structures: Recommendations tailored to the unique dynamic responses of floating offshore platforms during seismic events.
• Analysis Methods: Description of seismic response analysis techniques including response spectrum analysis, time history analysis, and nonlinear pushover analysis.
• Geological Secondary Hazards: Brief guidance on managing risks from soil liquefaction, seabed slides, fault displacements, tsunamis, mud volcanoes, and shock waves.

Applications

ISO 19901-2:2026 is vital for organizations engaged in the design, construction, and assessment of offshore oil, gas, and renewable energy structures. Applications include:

• Offshore Oil and Gas Platforms: Ensuring the seismic resilience of fixed and floating exploration and production facilities.
• Offshore Wind and Renewable Energy Foundations: Addressing the seismic safety of wind turbine support structures and other renewable energy installations.
• Infrastructure in High Seismic Zones: Providing requirements for projects with high consequence levels in seismically active marine environments.
• Regulatory Compliance: Facilitating adherence to national and international safety regulations for offshore seismic design.
• Lifecycle Risk Management: Supporting engineers, safety officers, and asset managers in evaluating site-specific seismic risks and setting tolerable risk levels for different limit states (e.g. ultimate, serviceability, and near-collapse states).
• Emergency Preparedness: Contributing to the development of structural and safety systems that protect human life and the environment in seismic events.

Related Standards

Implementing ISO 19901-2:2026 is most effective when combined with the following ISO standards and industry specifications:

• ISO 19900: General requirements for offshore oil and gas structures.
• ISO 19902: Design requirements specifically for fixed steel offshore structures.
• ISO 19903, 19904-1, 19905 Series, ISO 19906: Additional standards focused on concrete structures, floating structures, jack-ups, and arctic offshore structures.
• IOGP S-631-11: Industry specification for fixed steel offshore structures.
• ASCE 7: Informs mass participation requirements for response spectrum analysis.

Adhering to ISO 19901-2:2026 helps offshore operators, engineers, and regulators achieve robust seismic design, minimize operational risks, and maintain compliance with global best practices for seismic safety in offshore structural engineering. For more information and guidance, consult the full suite of ISO offshore structure standards and engage with technical committees specializing in offshore structures and seismic resilience.