The International Marine Contractors Association’s (IMCA’s) latest guidance ‘Guidelines for the Measurement of Depth of Burial’ (IMCA S 029) aimed at both the offshore renewables and offshore oil and gas industries, looks at the different methods of measuring the depth of burial of subsea cables and pipelines together with factors influencing the depth of burial.
It also includes measuring the thickness of an embankment of crushed rock on top of a pipeline or cable; and provides guidance on measurement of depth of lowering – including explanation of the difference between lowering and burial or cover.
Subsea pipelines and cables are commonly buried in the seabed or covered with crushed rock to give them protection from anchoring and bottom trawling. They can also be buried/covered to maintain an operating temperature and, in the case of pipelines, to be restrained from upheaval buckling. Some pipelines and cables are left exposed on the seabed to permit thermal expansion or left in an open trench designed to protect the line from passage of an anchor or trawl. ‘Depth of Burial’ or ‘Depth of Cover’ becomes a contractual requirement and therefore needs to be measured with equipment and procedures that produce results of known accuracy.
