ISO 23212:2021

Overview

ISO 23212:2021 specifies the basic dimensions and technical requirements for PN 10 flange connections used for bunker fuel and lubricating oil bunkering on ships. It covers PN 10 flanged connections for transfer from bunkering vessels or onshore facilities to ships, including dimensional tables, part configurations and essential design requirements. This standard is not applicable to ship fuel system connections for liquefied natural gas (LNG).

Key topics and technical requirements

• Scope and classification
  • Applies to PN 10 flange connections for bunker fuel (Type F) and lubricating oil (Type L).
  • Execution variants: Execution 1 (blind flange, no handle), Execution 2 (one handle), Execution 3 (two handles).
• Basic dimensions
  • Main dimensions, bolt patterns and blind-flange layouts are defined in figures and tables (DN ranges up to DN 300).
  • Sealing surface dimensions follow ISO 7005-1; flat gasket dimensions follow ISO 7483.
• Pressure rating
  • Minimum flange pressure rating: ≥ 1 MPa.
• Fasteners and hardware
  • Fasteners comply with ISO 4014 (hexagon head bolts), ISO 4032 (nuts) and ISO 7091 (washers).
  • Typical bolt sizes given (e.g., M16, M20) and strength classes specified in tables.
• Materials and gaskets
  • Flanges: steel with tensile strength ≥ 400 MPa or equivalent.
  • Fasteners: steel at specified strength classes; corrosion-resistant alternatives permitted without coating.
  • Gaskets: elastic, oil-resistant materials suitable for –40 °C to +50 °C.
• Coatings, marking and packaging
  • External paint consistent with ship fuel/lube systems; anti-corrosion coating required for fasteners unless stainless.
  • Mandatory marking includes manufacturer, reference to ISO 23212, type/execution, DN, nominal pressure and material grade.
  • Packaging must protect sealing surfaces and welding edges.
• Installation
  • Recommended installation axis height: 600 mm to 1 000 mm above deck.

Applications and users

ISO 23212 is intended for:

• Shipyards and marine equipment manufacturers designing and fabricating bunkering flanges
• Naval architects and marine engineers specifying ship fuel and lubricating oil receiving connections
• Bunkering operators and onshore facility designers ensuring compatible flange interfaces
• Classification societies, procurement teams and maintenance crews for conformity, inspection and replacement

Practical uses include new-build specifications, retrofits, spare-part procurement, installation guidance and interoperability checks during bunkering operations.

Related standards

Normative references integral to ISO 23212 include:

• ISO 4014, ISO 4032, ISO 7005-1, ISO 7091, ISO 7483

Keywords: ISO 23212, flange connection, PN 10, bunker fuel, lubricating oil, ships, flange dimensions, marine bunkering, fasteners, gaskets, pressure rating.