Protecting Offshore Pipelines Against Drifting Ice: A Discussion on Standards and Guidelines

In freezing waters, seabed gouging ice features (icebergs, pressure ridges) are a threat to offshore pipelines, which must be buried to a safe depth. Several standards and guidelines addressing this issue are examined and compared. The type of information that each code deems significant varies considerably — factors that are important to some code writers are not to others. API RP 2N, CSA-ISO 19906, CSA Z662 and DNV OS F101 direct the users to specific factors that either must or could be considered for design, but do not indicate what is to be done with them. In contrast, the RMRS rules are highly prescriptive. From a code user’s perspective, a comprehensive listing of all factors involved in ice-seabed-pipe interaction might provide better guidance in assessing what needs to be considered. This assessment could also be divided into three distinct operations: determination of design gouge depth, determination of clearance below the design gouge depth, and determination of pipeline response.