DNV issues a new steel wire rope mooring standard

2009-05-12

The increase in exploration and production activities in deep waters has made the use of steel wire ropes as segments in mooring systems more common. This trend has motivated DNV and industry partners to issue a new steel wire rope mooring standard.

In addition to the developments in mooring systems, there are a number of reasons for issuing this new standard,” explains Per Lohne, who is responsible for the standard in DNV.

DNV’s current Certification Note 2.5 ‘Certification of Offshore Mooring Steel Wire Ropes’ has been in effect since 1995, so an update of it is due. Additional research has been done and more experience has been gained, both of wire rope fabrication and the use of wire rope in deep water mooring systems.

“Also, forged sockets and duplex stainless steel grades for pins have been taken into use in the past few years. Hence, detailed requirements for these products are needed. For example, experience has shown that the performance criteria for the socketing compound and corrosion protection measures must be modified,” says Per Lohne.

The standard compiles updates in one document
The new DNV steel wire rope mooring standard (DNV-OS-E304) stipulates requirements as to materials, the fabrication process, product quality and certification for the manufacture of offshore mooring steel wire ropes and sockets. The standard will enable manufacturers to fabricate, and obtain DNV certification for, their wire ropes and sockets in compliance with current market requirements.

The main content of the standard deals with Design, Materials, Manufacture and Testing, including Documentation and Certification requirements.

A new set of mooring standards available
In response to the recent research and development and the industry’s operational experiences with mooring systems, DNV has released a complete set of Offshore Standards covering systems design, materials, product quality, certification requirements and the fabrication process:

• DNV-OS-E301 Position Mooring (issued October 2008), update of previous revision
• DNV-OS-E302 Offshore Mooring Chain (issued October 2008), new Standard
• DNV-OS-E303 Offshore Mooring Fibre Ropes (issued April 2008), new Standard
• DNV-OS-E304 Offshore Mooring Steel Wire Rope (issued April 2009), new Standard

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