ISO 10439-4:2015

Overview

ISO 10439-4:2015 - "Petroleum, petrochemical and natural gas industries - Axial and centrifugal compressors and expander-compressors - Part 4: Expander-compressors" specifies minimum requirements and recommendations for expander-compressors used in the petroleum, petrochemical and natural gas sectors. It supplements the general requirements in ISO 10439‑1:2015 and is aligned with industry practice (based on API 617). The standard covers design, materials, testing, inspection and supplier documentation for machines that handle gas or process air in special-purpose applications.

Key topics and technical requirements

ISO 10439-4:2015 addresses practical and technical subjects essential to reliable expander-compressor equipment:

• Scope and definitions: Terms, units and statutory requirements.
• Materials and casings: Pressure-containing casings, material inspection and repair guidelines.
• Rotating elements & dynamics: Shaft, sleeves, impellers, balancing and vibration control.
• Bearings and seals: Hydrodynamic radial/thrust bearings, bearing housings and expander-compressor shaft seals.
• Integral gearing: Requirements for integrally geared designs and single-shaft machines.
• Accessories and systems: Drivers, couplings, lubrication and sealing systems, mounting, piping and protection (overspeed shutdown, guards).
• Instrumentation & monitoring: Vibration, position monitoring, and hydraulic/magnetic bearing controls.
• Inspection and testing: Wheel shaker tests, mechanical running tests, assembled machine gas leakage tests and optional tests prior to shipment.
• Supplier documentation: Required datasheets, vendor drawing/data requirements (VDDR), curves and supplier proposals.
• Informative annexes: Datasheets (normative Annex A), vendor data requirements, nomenclature, typical materials, inspector checklists, nozzle forces and lubrication/sealing guidance.

Practical applications and who uses it

ISO 10439-4:2015 is used to ensure safe, reliable and consistent expander-compressor equipment in process plants. Typical users include:

• Original Equipment Manufacturers (OEMs) designing and building expander-compressors.
• Engineering, Procurement and Construction (EPC) firms specifying equipment for projects.
• Plant operators and maintenance teams implementing inspection, testing and repair regimes.
• Quality inspectors and third‑party certifiers verifying compliance with industry requirements.
• Procurement and contracting teams preparing tenders and acceptance criteria.

Using this standard helps reduce technical disputes, ensure compatibility with plant systems, and provide clear supplier data and testing expectations.

Related standards

• ISO 10439-1:2015 - General requirements (referenced for overarching rules).
• ISO 10439-2 / ISO 10439-3 - Part 2: Non-integrally geared and Part 3: Integrally geared centrifugal compressors.
• API 617 - Source basis referenced in the introduction.

Keywords: ISO 10439-4:2015, expander-compressors, axial and centrifugal compressors, petroleum industry, petrochemical, natural gas, compressor standards, API 617.