DNV GL introduces recommended practice for subsea lifting
The completion of a joint industry project (JIP) to improve existing standards and regulations around subsea lifting operations has resulted in a new recommended practice (RP). DNV GL developed the RP to provide guidance on the proper design and correct operation, as well as regular inspection and maintenance, of subsea cranes and lifting appliances. The aim is to reduce the overall risk and safeguard personnel during lifting operations and to improve the integrity and efficiency of equipment throughout its lifetime.
Demand for subsea lifting operations is increasing and becoming more complex with more activity taking place in deeper and harsher environments resulting in stricter lifting requirements. The rapid development of subsea cranes and lifting appliances to keep pace with the market has subsequently introduced several technical challenges around safe and efficient deployment and recovery of objects to and from the seabed.
“Existing standards and regulations don’t cover modern subsea lifting operations sufficiently,” Ivar Kvaleid, DNV GL Project Manager for the RP, said. “Subsea lifting is a complex area as it involves many technical, environmental and management aspects. This is currently defined by clients’ specifications, technological boundaries and manufacturers’ considerations, rather than regulative processes and procedures. The RP will ensure a unified safety approach and increase the overall awareness of risks from subsea lifting activities and how to best manage these risks.”
The RP is applicable to lifting appliances used in subsea lifting operations. In practice this generally means an offshore or subsea crane, an A-frame with winch or other types of winch system and covers lifting of unmanned objects. The recommendations provide guidelines on the evaluation of existing lifting appliances as well as the design and qualification of new lifting systems for subsea operations.
Challenges related to modern subsea lifting operations such as higher lifting capacities, greater water depths and the inclusion of motion compensation systems, are covered to a lesser degree in the present industry codes.
“The objective of the RP is to provide recommendations and guidance on important aspects relating to operational parameters, risk management, related technical challenges, engineering solutions, maintenance and inspection, to ensure safe execution of subsea lifting operations,” Mr Kvaleid said.
Eighteen key international offshore players were involved in the initial JIP project which started in January 2012: Statoil, BP, ExxonMobil, Petrobras, Lundin Norway, Marathon Oil Norge, Technip, Subsea7, Saipem, Heerema Marine Contractors, McDermott, MacGregor (Cargotec), TTS Energy, Liebherr, Rolls-Royce/Huse Engineering, Cranemaster, Samson Rope and W. Giertsen Services.