ISO 17939:2015

Overview - ISO 17939:2015 (Oil tank hatches)

ISO 17939:2015 establishes requirements for oil tank hatches used on ships and other marine structures to ensure interchangeability, structural integrity and watertight performance. The standard specifies classification, structure and main dimensions, materials, quality of manufacture, testing of watertightness and designation for a range of hatch types. It aligns with the International Convention on Load Lines 1966 (ILLC66) and meets IACS UR S26 requirements. While ISO 17939:2015 defines key dimensions and components, remaining detailed design elements (welding, secondary dimensions) are left to the manufacturer. Users must also ensure compliance with applicable statutory and classification society rules.

Key topics and technical requirements

• Classification and types: Defines hatch categories (A1, A1F, A2, A2F, B, BF, C1, C1F, C2, C2F) to cover flat, curved and combined configurations for circular and long-circular openings.
• Main dimensions and nominal sizes: Provides dimensional tables and figures for standard nominal sizes (examples: A-type circular hatches 600–1 200 mm; B-type long circular 600×800 up to 850×1 500 mm; C-types for combined openings).
• Structure and components: Specifies typical hatch elements such as coaming, cover plate, seal ring, clamping ring, clamp plate, lock catch, wing clamp, actuators and bearing pads to achieve oil-tight performance.
• Materials and manufacture: Addresses material selection and quality of manufacture, including surface treatment and rust protection in line with ISO 8501‑1 visual preparation guidelines.
• Watertightness testing: Requires testing procedures to verify oil‑tight integrity; testing and designation requirements are included to ensure interchangeability and performance.
• Application positions and stiffening: Notes consideration of installation positions (position 1 and position 2) and the need for additional stiffening where necessary.
• Designation and documentation: Defines how hatches should be designated and documented for identification and installation.

Practical applications and who uses ISO 17939:2015

• Shipbuilders and hatch-cover manufacturers - for standardized design, production and interchangeability.
• Naval architects and marine engineers - to specify hatch types, dimensions and structural requirements during vessel design.
• Classification societies and surveyors - to assess compliance with IACS UR S26 and load‑line requirements.
• Ship owners, operators and shipyards - for procurement, retrofit and maintenance of oil-tight hatch covers.
• Regulators and flag administrations - as part of compliance checks against statutory load-line rules.

Users should apply ISO 17939:2015 together with applicable statutory regulations and classification society rules to ensure full compliance.

Related standards and references

• ISO 8501‑1 (surface preparation - rust grades and preparation grades)
• International Convention on Load Lines 1966 (ILLC66)
• IACS Unified Requirement S26 (UR S26)