Overview
ISO 15138:2018 - Petroleum and natural gas industries - Offshore production installations - Heating, ventilation and air‑conditioning (HVAC) - specifies requirements and guidance for the design, testing, installation and commissioning of HVAC and pressurization systems on offshore production installations (new or existing, fixed or floating registered as production installations). The standard is applicable to normally occupied and unoccupied areas and is intended as the overall facility HVAC reference; where Class or IMO/MODU codes apply the user is directed to those rules but should apply ISO 15138 when they are less stringent.
Key technical topics and requirements
- Design basis and philosophy: development of a clear HVAC design basis, prioritizing simplicity and passive systems, robustness, diagnostics, sparing and maintainability.
- Ventilation & pressurization: guidance on natural and mechanical ventilation, pressurization systems, and air‑change considerations (AC/h) relevant to living quarters, process areas, temporary refuge and emergency spaces.
- Hazardous area interfaces: hazardous area classification and the role of HVAC in controlling vapour accumulation and maintaining safe zones; coordination with IEC 60079 series and API/IMO guidance.
- Environmental and operational conditions: consideration of offshore exposures, temperature limits, corrosion and material selection.
- Controls, margins and modelling: selection of control philosophies, design margins, and use of wind‑tunnel and computational fluid dynamics (CFD) for performance verification.
- Area‑specific designs: prescriptive guidance for process/utility areas, living quarters, temporary refuge (TR), drilling areas, gas turbines, engine rooms, battery rooms, laboratories, purge systems, rooms protected by gaseous extinguishing agents, watertight compartments, air locks, stairs and escape routes.
- Equipment, installation and commissioning: normative annexes on equipment selection, datasheets (AHUs, coils, DX systems), duct earthing and installation/commissioning checks.
- Operation & maintenance: informative annexes covering maintenance, testability and lifecycle considerations.
- Updates in 2018 edition: additions include black‑start requirements, stairways/escape route and air‑lock requirements, GWP refrigerant phase‑down/phase‑out guidance, filtration updates and fail‑safe fire‑damper criteria.
Practical applications - who uses this standard
- Offshore HVAC designers and mechanical engineers specifying systems for production platforms
- Project engineers and EPC contractors preparing design documentation, datasheets and installation work scopes
- Operators and asset owners setting performance and maintenance requirements for living quarters, control rooms and safety systems
- Classification societies, HSE and regulatory reviewers verifying compliance or equivalence with IMO/MODU/Class rules
- Manufacturers and vendors of AHUs, ductwork, filters and refrigerant systems supplying offshore equipment
Related standards and references
ISO 15138:2018 cross‑references multiple industry standards and codes (examples: IEC 60079 series for explosive atmospheres, API RP 505 for hazardous‑area classification, IMO/MODU resolutions, EN/ISO fan and AHU performance standards and ASHRAE guidance). Users should coordinate ISO 15138 requirements with project‑specific Class and IMO obligations.
Keywords: ISO 15138:2018, offshore HVAC, heating ventilation air‑conditioning, petroleum and natural gas, offshore production installations, HVAC design, pressurization, hazardous area ventilation, CFD, AHU.