Heating / Control Systems / De Ice

De-Icing and Anti-Icing

In cold climate waters, the formation of ice on ships and offshore platforms can create serious problems impacting the safety of personnel and the economies of operation. Icing can be caused by sea spray and/or atmospheric water (snow, rain and fog). The quipment and areas requiring measures against ice formation have been divided into two categories by Det Norske Veritas (DNV), as follows:

Category I: equipment or areas necessary for navigation, steering, propulsion, anchoring and lifesaving.

Category II: equipment or areas comprising decks and superstructures, helicopter decks, railings and cargo deck area.

Anti-icing is defined as the prevention of ice formation, and according to DNV is required for Category I equipment or areas. For these applications, anti-icing arrangements are required with sufficient capacity to keep the equipment or areas free from ice at all times in the service areas under moderate conditions.

Deicing is defined as the melting of ice already formed, and according to DNV is required for Category II equipment or areas. For these applications, deicing arrangements are required with sufficient capacity for removal of accumulated ice within a reasonable period of time (normally 4 to 6 hours) under moderate conditions.

Heat Load
DNV recommends power capacity for anti-icing and deicing be not less than:


300 W/m2 for open deck areas, helicopter decks, gangways, stairways
200 W/m2 for superstructures
50 W/m for railings with inside heating

These are minimum power capacity requirements. Lower ambient temperatures and higher wind speeds will increase the heat loss and more power may be needed.

Flat Surface Heat Loads
The calculated heat loads required for anti-icing of flat surfaces based on various combinations of ambient temperature and wind speed are shown below. These heat loads are for flat horizontal steel surfaces with
a maintain temperature of 2°C. Flat surfaces include decks, access ways, escape ways, helidecks, etc.