IACS Unified Requirements for Building Polar Class Vessels

Various Classification Societies have had their respective requirements for Polar Class ships. The International Association of Classification Societies (IACS) Unified Requirements harmonize the rules to be used in the construction of all ships meant to operate in ice-covered waters, including areas where multi-year ice may be present. These Unified Requirements came into effect in March 2008.

Important Highlights of the IACS Unified Requirements

Section 12

  • Hull areas (12.2)
  • Design ice loads (12.3)
  • Peak pressure factors (12.3)
  • Shell Plate requirements (12.4)
  • Framing-transversely framed, longitudinally framed, structural stability (12.5-12.9)
  • Corrosion/abrasion additions and steel renewal (12.11)
  • Materials (12.12)
  • Longitudinal strength (12.13)
  • Appendages (12.15)
  • Welding (12.18)

Section 13

Section 13 details machinery requirements for Polar Class ships, such as the main propulsion, steering gear, emergency and auxiliary systems essential for a ship’s safety and the survivability of the crew. Machinery and supporting systems are to be designed so that they can function properly in the freezing temperatures in the Arctic. Systems that are subjected to damage as a result of freezing are to be made drainable.

Auxiliary Systems

Machinery needs to be protected from the harmful effects of ingestion or accumulation of snow. Measures need to be taken to prevent damage due to freezing to tanks containing liquids, sea bays, ice boxes, ship side valves, fittings above load waterline, and ballast tanks. Vent pipes, intakes and discharge pipes, and associated systems are to be designed to prevent blockage due to freezing and ice or snow accumulation. There needs to be a way of re-circulating the seawater. Accommodation and ventilation system intakes are to be provided with means of being heated.