Overview
ISO/TR 13881:2000 - Petroleum and natural gas industries: Classification and conformity assessment of products, processes and services - provides guidance for selecting an appropriate conformity assessment approach based on risk. The Technical Report defines two classification methods (a calculation-based model and a judgement-based model) and five conformity assessment systems (Systems A–E). It links product/process/service CLASS (1–5, where Class 1 = highest risk and Class 5 = lowest risk) to the level of conformity assessment required.
Keywords: ISO/TR 13881:2000, conformity assessment, classification, petroleum and natural gas industries, risk-based classification.
Key Topics
- Classification principles
- Whole-life perspective (from functional specification to decommissioning)
- Consideration of health, safety and environmental requirements
- Use of verifiable parameters for CLASS determination
- Two classification methods
- Calculation-based method: combines a risk-related sub‑model (total risk Tr computed from probabilities and consequences of failure for design, manufacturing/execution and other causes) and an integrity-related sub‑model (verification and conformity assessment costs). CLASS is iterated until risk and verification costs are balanced.
- Judgement-based method: multidisciplinary expert team evaluates intended use, foreseeable misuse, design maturity, effects on health/safety/environment, reliability, OPEX/CAPEX impacts, and supplier confidence. Uses a structured checklist and documented rationale.
- Conformity assessment systems (Systems A–E): five increasing levels of confidence; CLASS determines which system is appropriate (Class 1 → System A ... Class 5 → System E).
- Key terms and controls
- Probability of failure, consequence of failure, risk = probability × consequence
- Design review, witness points, hold points, verification planning
- Documentation and traceability of classification decisions
Applications
- Procurement and contracting in oil & gas projects: helps purchasers decide the level of independent assessment required for equipment, processes or services.
- Supplier evaluation and quality assurance: aligns supplier conformity assessment activities to assessed risk.
- Project risk management and specification drafting: integrates with functional and technical specifications (ISO 13879 / ISO 13880).
- Useful for operators, engineering contractors, QA/QC managers, conformity assessment bodies and regulators involved in onshore and offshore petroleum and natural gas projects.
Related Standards
- ISO 13879 - Content and drafting of a functional specification
- ISO 13880 - Content and drafting of a technical specification
- ISO/IEC Guide 2, 22, 28 - conformity-assessment vocabulary and models
- ISO 9001 / ISO 9002 / ISO 9003 - quality management system references
Practical value: ISO/TR 13881:2000 provides a structured, risk-based foundation to select an appropriate conformity assessment system that matches the severity of potential failures in petroleum and natural gas industry assets and activities.