phase 4 report - DNV

RN02: DESIGN OF FLOATING STRUCTURES IN ICE // PART 4 Guidance Document: Additions and Amendments to ISO 19906:2010(E)1 ScopeThis International Standard specifies requirementsand provides recommendations and guidance forthe design, construction, transportation, installationand removal of offshore structures, related to theactivities of the petroleum and natural gas industriesin arctic and cold regions. Reference to arctic andcold regions in this International Standard is deemedto include both the Arctic and other cold regionsthat are subject to similar sea ice, iceberg and icingconditions. The objective of this InternationalStandard is to ensure that offshore structures inarctic and cold regions provide an appropriatelevel of reliability with respect to personnel safety,environmental protection and asset value to theowner, to the industry and to society in general.This International Standard does not containrequirements for the operation, maintenance, servicelifeinspection or repair of arctic and cold regionoffshore structures, except where the design strategyimposes specific requirements (e.g. 7.1.6 and 17.2.2).While this International Standard does not applyspecifically to mobile offshore drilling units (see ISO19905-1), the procedures relating to ice actions andice management contained herein are applicable tothe assessment of such units.This International Standard does not apply tomechanical, process and electrical equipment or anyspecialized process equipment associated with arcticand cold region offshore operations except in so faras it is necessary for the structure to sustain safelythe actions imposed by the installation, housing andoperation of such equipment.Design experience with stationary floating structuresin ice is scarce. Most of the experience on which thisstandard is based applies to fixed (bottom founded)structures. Not all experience is directly transferableto floating structures in ice and the standard shouldbe used with appropriate caution.3 Terms and definitions3.5action effecteffect of actions on the structure or its componentsEXAMPLE: Internal force, moment, stress or strain.3.9broken icevarying sizes of ice floes, broken up as a result ofnatural processes, active or passive interventionNOTE: Active intervention includes ice managementresulting in managed ice; passive interventionincludes the channel, or wake, caused by a stationarystructure in moving ice cover.3.38ice managementsum of all activities where the objective is to reduceor avoid actions from any kind of ice features.NOTE: ice management includes, but is not limited to:––Detection, tracking and forecastingof sea ice, ice ridges and icebergs––Threat evaluation and alerting––Physical management, such as icebreaking and iceberg towing3.83 (new)ice eventice-structure interaction event for which ice actionsare calculatedNOTE: an ice-structure interaction event can beassociated with discrete ice features such asicebergs, ice islands, ice ridges, stamukhiand ice floes, or with a specified lengthor duration arising from the interactionprocess.3.84 (new)surchargeincrease in ridge keel depth used in calculationsarising from the downward extrusion of ice rubbleduring ice ridge interaction on sloped and/or conicalstructures3.85 (new)ice beltstrengthened hull region around the waterline,accounted for all loading conditions, given by iceclass requirements66RUSSIAN–NORWEGIAN COOPERATION PROJECT