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Abstract This paper describes recent changes to procedures for certification of synthetic-fiber deepwater mooring lines. Requirements are introduced for certification of yarns with a fit-for-service approach. Approval programs for Manufacturers have been requested by industry; these now form part of the procedures for end-product certification. The changes are discussed, together with the practical implications to the industry of the three documents DNV-OS-E303 and approval programs 321 & 322. The documents discussed in this paper cover approval of manufacturers for load-bearing yarns, approval of manufacturers of offshore-mooring fiber ropes, and the certification of actual deliveries. Further use of the documents can be as basis for specifying mooring lines, contractual agreement between purchaser and supplier, and in connection with manufacturing and documentation independently of certification. The main change compared to the previous issue of DNV-OS-E303 is that material requirements to load-bearing yarns have been introduced. The material requirements to delivery yarns are included in the update of DNV-OS-E303, whilst the requirements for approval of the manufacturers of yarns and ropes are introduced in the two new documents, approval programs 321 & 322. Materials that may be used under these procedures are expanded to include aramid and HMPE. Other materials can also be covered. Failure modes for different yarns are taken into account and the in-service condition assessment is gone more thoroughly into. The documentation requirements for mobile and long-term moorings are split in two, which reduces the requirements to mobile moorings. The scope of testing of subropes and full ropes are split accordingly and requirements to TTR- or creep testing have been added. Requirements to termination hardware have been reformulated, and the scope of survey for rope manufacturing has been specified in a similar way as for offshore mooring chain. The new documents will impact the certification process for the industry in several ways. The amount of documentation to be submitted for each delivery is substantially reduced. With the introduction of material requirements and approval programs for manufacturers the focus on the right rope for the application has been emphasized. Introduction For certification of synthetic-fiber ropes for deepwater mooring under the auspices of Det Norske Veritas (DNV), the requirements can now be found in three documents, each covering important steps in the process of obtaining complete end-product certification:DNV-OS-E303 " Offshore Mooring Fibre Ropes??, October 2010.Standard for Certification No. 2.9, Approval Programme No. 321 " Offshore Mooring Fibre Ropes??, Nov. 2010.Standard for Certification No. 2.9, Approval Programme No. 322 " Yarns for Offshore Mooring Fibre Ropes??, November 2010. |
