ISO 21562:2020

Overview

ISO 21562:2020 - Ships and marine technology - Bunker fuel mass flow meters on receiving vessel - Requirements - defines technical, metrological and security requirements for Coriolis mass flow meter (MFM) systems installed on ships to measure bunker fuels received. The standard focuses on accurate onboard measurement for bunker receipt (non-custody-transfer), specifying design, testing, calibration and verification practices to achieve reliable mass measurement and reduce bunkering disputes.

Key topics and technical requirements

• Scope and exclusions
  • Applies to Coriolis MFM systems on receiving vessels for bunker fuels (Class F).
  • Does not cover custody-transfer meters or cryogenic fuels (LNG). For custody transfer see ISO 22192.
• Design and materials
  • Metallic casings and pressure-retaining parts; corrosion-resistant fasteners for fluid-contacting components.
  • Threaded fittings not used for pipe sizes > DN 50.
• Environmental and mechanical tests
  • Prototype environmental testing: vibration, temperature and weather tightness (IACS-acceptable).
  • Hydrostatic test at 1.5× MAWP (maximum allowable working pressure).
  • Operating ambient temperature range: −40 °C to +60 °C.
  • Minimum pressure rating: ≥ 1 MPa.
• Metrology and calibration
  • MFM must be calibrated prior to installation; calibration fluid may be water or hydrocarbon equivalent.
  • Calibration traceable to SI mass units by an ISO/IEC 17025 laboratory or OIML issuing authority.
  • Device-level calibration requirement: maximum measurement uncertainty ≤ 0.2% (device); system guideline: ≈ 0.5% expanded uncertainty for bunker fuel applications, accounting for product and process influences.
  • Verification on board by a qualified independent party.
• Security and data
  • Requirements for equipment security, software integrity and measurement data recording to ensure tamper-evident, auditable records.
• Marking and documentation
  • Mandatory markings (manufacturer, serial, MAWP, flow direction, transmitter info, year).
  • Procedural guidance for commissioning, verification, start/end of receipt and record keeping.

Applications and users

ISO 21562:2020 is practical for:

• Shipowners, operators and chief engineers implementing onboard metering for bunker receipts
• Naval architects and shipbuilders specifying MFM installations
• Fuel metrology laboratories and calibration houses (ISO/IEC 17025)
• Classification societies, port authorities and marine surveyors performing verification and acceptance
• MFM manufacturers and system integrators developing shipboard Coriolis measurement systems

Benefits include improved accuracy of bunker quantity records, fewer disputes with suppliers, and standardized commissioning and verification procedures.

Related standards

• ISO 8217 (bunker fuel specification)
• ISO 22192 (Coriolis MFM for custody transfer)
• OIML R117 (flow meter recommendations)
• ISO/IEC 17025 (calibration laboratory competence)

Keywords: ISO 21562:2020, bunker fuel mass flow meters, Coriolis MFM, metrology, calibration, bunker receipt, marine measurement standards.