ISO 3977-9:2024

Overview

ISO 3977-9:2024 - "Gas turbines - Procurement - Part 9: Reliability, availability and maintainability" is a procurement-focused International Standard that establishes a common basis for exchanging R, A & M information between gas turbine manufacturers, users, consultants, regulators, insurers and others. Applicable to all elements of the gas turbine and auxiliaries, the standard defines terms, describes component life expectancy and repairs, and sets out criteria for determining inspection and overhaul intervals.

Key topics and technical requirements

• Definitions and terminology: Harmonised R, A & M vocabulary linked to ISO 3977‑1, ISO 3977‑3, ISO 11086 and related standards to ensure consistent communication.
• Maintainability: Defines maintainability and prescribes the use of the planned outage factor (POF = planned outage hours / period hours) as a basic measure. It also specifies use of average forced outage period (FOP = forced outage hours / number of forced outages).
• Manufacturer responsibilities:
  • Provide inspection schedules addressing component lifing, coating lifing, inspection intervals and how operating regime, fuel type and water/steam injection influence inspections.
  • Recommend methods for interval determination (e.g., equivalent operating hours or regime‑based schedules with multipliers).
  • Guidance on on-line inspection and on-line maintenance, condition monitoring and running maintenance.
• User responsibilities: Collaborative exchange of maintenance data, use of operating log sheets and adherence to manufacturer procedures.
• Spare parts and repairs: Guidance on spare parts provisioning and repair/overhaul criteria to support reliability and availability targets.
• Reliability and availability metrics: Requirements for reliability acceptance tests and for calculating and reporting reliability and availability (including start reliability and forced/planned outage reporting).

Practical applications and who uses it

ISO 3977-9:2024 is used during procurement, contract negotiation, technical due diligence and lifecycle planning. Typical users:

• Gas turbine manufacturers and OEMs (to specify inspection/maintenance deliverables)
• Plant owners/operators and asset managers (to set maintenance strategy and availability targets)
• Engineering consultants and maintenance contractors (to align procedures and overhaul intervals)
• Regulators and insurance companies (to evaluate risk, performance claims and compliance)
• Procurement teams (to include R, A & M clauses in tender documents and contracts)

Related standards

• ISO 3977-1 (General introduction and definitions)
• ISO 3977-3 (Design requirements)
• ISO 11086 (Gas turbines - Vocabulary)
• ISO 19859 (Gas turbine applications - Power generation)
• ISO 12100 (Safety of machinery - Risk assessment)

Keywords: ISO 3977-9:2024, gas turbines, reliability, availability, maintainability, RAV, procurement, inspection schedules, condition monitoring, overhaul intervals.