ISO 19901-9:2019

Overview

ISO 19901-9:2019 - Structural integrity management (SIM) provides principles, requirements and recommendations for managing the structural integrity of fixed steel offshore structures in the petroleum and natural gas industries. The standard applies to caissons (free‑standing and braced), jackets, monotowers, towers and associated topsides items (main decks, deck legs, crane pedestals, helidecks, derricks, flare booms, lifeboat davits, etc.). It is also applicable, as relevant, to compliant bottom‑founded structures, steel gravity structures, jack‑ups and related structures (underwater storage tanks, bridges and connectors).

Key topics and technical requirements

ISO 19901-9 structures its guidance around a lifecycle SIM approach and includes requirements for planning, engineering and execution of integrity tasks. Major technical topics include:

• SIM fundamentals - limit states, performance levels, fitness‑for‑service principles and management framework.
• SIM process - stepwise workflow for integrity management from data collection through decision-making.
• SIM data - data requirements, handling of missing data and data management best practices.
• SIM evaluation and risk - identification of hazards, degradation mechanisms, critical structures, risk evaluation (consequence and likelihood) and risk presentation.
• Assessment methods - qualitative, semi‑quantitative and quantitative assessments including fatigue analysis and fitness‑for‑service demonstrations.
• Assessment modelling - modelling of tubular members, connections, conductors, damaged or repaired elements and foundation models.
• SIM strategy - inspection, maintenance, monitoring (weight/CoG, deck elevation, natural frequency, corrosion protection, metocean monitoring) and evacuation strategies.
• SIM program - inspection, maintenance and monitoring program specifications, inspection types and intervals, and implementation considerations.
• Special evaluations - assessment for reuse at new locations and evaluation for future removal.

Practical applications

ISO 19901-9 is used to develop and implement structured integrity management programs for offshore assets to ensure safety, regulatory compliance and cost‑effective lifecycle management. Typical applications:

• Creating inspection and monitoring programs for jackets, caissons and topsides.
• Performing fitness‑for‑service assessments and fatigue evaluations for in‑service structures.
• Assessing existing structures for continued service, relocation (reuse) or decommissioning/removal.
• Defining inspection scopes, intervals and inspection methods based on risk and criticality.
• Integrating SIM outputs into asset integrity management systems and maintenance planning.

Who should use this standard

• Structural and offshore engineers
• Asset integrity and inspection managers
• Operators and platform owners in petroleum and natural gas industries
• Inspection and corrosion specialists
• Engineering consultancies and regulatory bodies

Related standards

ISO 19901-9 should be used alongside other parts of the ISO 19901 series and applicable national/international offshore design, inspection and fitness‑for‑service codes to form a complete integrity management framework.

Keywords: ISO 19901-9:2019, structural integrity management, SIM, offshore structures, inspection program, fitness-for-service, offshore jackets, caissons, topsides, fatigue analysis, risk assessment.