Arctic Ice Regime Shipping System (AIRSS)

The Arctic Ice Regime Shipping System (AIRSS) is a regulatory standard currently in use only outside the Zone/Date System (Z/DS) , as a requirement of the Arctic Shipping Pollution Prevention Regulations. Based on the success of the AIRSS , the potential exists for broader application of the AIRSS , with the Z/DS acting as guidelines. Visibility, vessel speed, manoeuvrability, the availability of an icebreaker escort, and the knowledge and experience of the crew must be considered when applying the AIRSS .

The AIRSS is intended to minimize the risk of pollution in Arctic waters due to damage of vessels by ice; to emphasize the responsibility of the shipowner and master for safety; and to provide a flexible framework for decision-making. It applies to CAC and Type (Baltic Class) ships, and requires accurate information for voyage planning, timely ice-charts, and consistent observation of ice conditions.

The AIRSS is a four-step process:

First, the user characterizes the ice regime. The ice regime is a region of ice with more or less consistent ice conditions. The ice regime takes into account several important factors of the ice; its concentration, thickness, age, state of decay, and roughness.

Second, the vessel Class dependant Ice Multipliers are obtained. Because different vessels have different capabilities in ice-covered waters, each vessel is assessed and assigned to a Vessel Class. This rating reflects the strength, displacement, and power of the vessel. The relative risk damage to a vessel by different types of ice is taken into account using “weighting” factors called Ice Multipliers.

Third, the information about the ice regime and the Ice Multipliers are combined to determine the Ice Numeral. (The Ice Numeral is a simple calculation that relates the strength of the ship to the danger presented by different ice regimes.)

Finally, the Ice Numeral is used to decide whether the vessel should proceed or take an alternative route. Ice regimes that are not likely to be hazardous have zero or ‘positive’ Ice Numerals; whereas, those regimes that could be dangerous have ‘negative’ Ice Numerals. As always, the safety of the ship is the responsibility of the master.


Intentional entry into a negative ice regime outside the Zone/Date System is prohibited. The master may consider taking one of the following actions:

  • Selecting another route
  • Obtaining more recent and/or higher quality ice information
  • Waiting for improved weather or ice conditions
  • Requesting the assistance of an icebreaker by calling NORDREG

When entry is permitted, mariners should select an operating speed that will allow them to avoid damaging impacts with ice.

When AIRSS is used for voyages outside of the existing Z/DS , there is a requirement for ships to have a qualified ice navigator on board and to submit the Ice Regime Routing Message and the After Action Report to the nearest Canadian Coast Guard Marine Communication and Traffic Services Centre ( NORDREG ) .

Arctic Ice Regime Shipping System Pictorial Guide - TP 14044

Arctic Ice Regime Shipping System Pictorial Guide - TP 14044