Overview
ISO 24201:2025 - Oil and gas industries including lower carbon energy - Tertiary outfitting structures is the first edition (2025) international standard that provides a uniform reference for tertiary outfitting items used in offshore oil, gas and lower-carbon energy projects. The standard applies primarily to topside systems for fixed and floating offshore projects and can be applied to hull systems or onshore projects with stakeholder consent. It defines dimensional requirements and design guidance for tertiary outfitting structures but does not replace classification society rules or specify clearances between items and other structures.
Key topics and technical requirements
ISO 24201:2025 organizes requirements by outfitting type and material (steel and aluminium). Key technical topics covered include:
- Handrails
- General configurations, end treatments, removable types, structural requirements and testing.
- Self-closing safety gates
- Design intent, structural criteria and test requirements.
- Stairs and spiral stairs
- Widths, headroom, nosing, treads, landings, structural requirements and testing.
- Vertical ladders
- Stile/rung requirements, spacing to obstructions, fall-protection devices, structural checks and tests.
- Grating
- Opening sizes, penetrations, material considerations and testing protocols.
- Access holes (manholes)
- Dimensional and functional requirements for safe access.
- Connection methods
- Selection of fastening types, prevention of self-loosening, nut and bolt guidance, grating fasteners and allowable capacities.
- Material-specific sections
- Separate requirements and tests for steel outfitting and aluminium outfitting to reflect different structural and fabrication properties.
The standard focuses on dimensions, structural requirements, and test methods rather than prescriptive clearance rules or classification society regulations.
Practical applications
ISO 24201 is intended to be used during design, fabrication, installation and inspection of tertiary outfitting on offshore platforms, FPSOs and other marine structures. Typical applications include:
- Defining handrail and stair geometry for topsides and walkways
- Specifying ladder and fall-protection arrangements for access systems
- Selecting grating types and fasteners for deck openings
- Standardizing manhole sizes and connection methods across projects
- Supporting procurement specifications and fabrication shop drawings
Who should use this standard
- Design engineers and naval architects working on offshore and lower-carbon energy facilities
- Offshore project managers and procurement teams specifying outfitting items
- Fabrication contractors and weld/assembly shops
- Safety engineers, inspectors and maintenance teams verifying compliance
- Asset owners seeking consistent tertiary outfitting across fleets
Related standards and notes
- ISO 24201:2025 complements (but does not replace) classification society rules and other ISO standards relevant to offshore structures and safety.
- When applying the standard to hull systems or onshore projects, obtain consent from relevant stakeholders as indicated by the document scope.
Keywords: ISO 24201, tertiary outfitting structures, offshore oil and gas, lower carbon energy, handrails, stairs, vertical ladders, grating, safety gate, access hole, connection method, topsides, outfitting design standards.