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Ch.2: Technical Provisions [Table of Contents]

DNV-OS-C401 Fabrication and Testing of Offshore Structures

[-] Ch.3: Certification and Classification

CHAPTER 3

Certification and Classification

Ch.3

SECTION 1
General

Ch.3 Sec.1
A. General Requirements

Ch.3 Sec.1
A 100   Introduction

Ch.3 Sec.1 A
101   As well as representing DNV's recommendations on safe engineering practice for general use by the offshore industry, the offshore standards also provide the technical basis for DNV classification, certification and verification services.

Ch.3 Sec.1 A
102   A complete description of principles, procedures, applicable class notations and technical basis for offshore classification is given by the DNV Offshore Service Specifications for classification, see Table A1.

Ch.3 Sec.1 A
Table A1 DNV Offshore Service Specifications 
No. Title  
DNV-OSS-101 Rules for Classification of Offshore Drilling and Support Units  
DNV-OSS-102 Rules for Classification of Floating Production and Storage Units  



Ch.3 Sec.1 A
103   Classification procedures and requirements specifically applicable in relation to the technical provisions in Ch.2 are given in this chapter of the offshore standard.

Ch.3 Sec.1
A 200   Assumptions

Ch.3 Sec.1 A
201   Any deviations, exceptions and modifications to the design codes and standards given as recognised reference codes shall be documented and approved by DNV.

Ch.3 Sec.1 A
202   Aspects of the design and construction provisions of this standard (Ch.2) which shall be specially considered, agreed upon, or may be accepted are subject to DNV approval when the standard is used for classification purposes.

Ch.3 Sec.1 A
203   DNV may accept alternative solutions found to represent an overall safety level equivalent to that stated in the requirements of this standard.

Ch.3 Sec.1
B. Specific Certification and Classification Requirements

Ch.3 Sec.1
B 100   General

Ch.3 Sec.1 B
101   The following requirements shall be applied in conjunction with the technical requirements given in Ch.2 and when used for certification or classification purposes.

Ch.3 Sec.1
B 200   Basic requirements

Ch.3 Sec.1 B
201   Welding of special, primary and secondary structures for hull, welding of superstructure, and equipment shall be carried out by certified approved welders, with approved welding consumables and at contractors recognised by DNV.

Ch.3 Sec.1
B 300   Contractors

Ch.3 Sec.1 B
301   Contractors will have to prove their qualifications for the welding operations in question.

Ch.3 Sec.1 B
302   It is assumed that the contractors make use of the necessary equipment for carrying out inspection of the welding operations in a satisfactory manner.

Ch.3 Sec.1 B
303   Important welding operations shall be carried out under daily supervision of an inspector, who has the experience and qualifications, which enable him to judge this type of work. The work of each welder shall be regularly examined.

Ch.3 Sec.1 B
304   The contractors shall keep a card index or register of all approved welders. The register shall give information on training of the welders and date and results of qualification tests. Information about the base metal, type of welding consumable, joint design and welding positions shall be stated in the event of re-qualification tests. The surveyor shall be allowed to examine the register at any time.

Ch.3 Sec.1
B 400   Welding consumables

Ch.3 Sec.1 B
401   Consumables for welding of offshore structures intended for classification shall be approved by DNV.

Ch.3 Sec.1 B
402   Type approval of welding consumables will be considered subject to compliance with the requirements given in the Rules for Classification of Ships Pt.2 Ch.3 Sec.4 and Standard for Certification No.2.9 Type Approval Programme No.1-401.1 'Welding Consumables'.

If, for some reason, the welding consumable is not approved, 1 extra tensile test (round specimen from the weld metal) can be cut from the assembly. However, this result is project specific.

Ch.3 Sec.1 B
403   All brand names under which a tested and approved welding consumable is marketed, shall be registered by DNV. In order to avoid duplication of tests, the manufacturer shall certify that the welding consumables marketed under alternative brand names are identical with the consumables tested for approval.

Ch.3 Sec.1
B 500   Welding procedures and qualification of welders

Ch.3 Sec.1 B
501   The contractor shall inform the surveyor about the welding/testing schedule. The surveyor shall be allowed to witness welding /testing at any time.

Ch.3 Sec.1 B
502   Where certification is performed by other IACS members or independent organisations, e.g. accredited or nationally approved certification bodies, recognition of such certification will be evaluated on a case by case basis. DNV reserves the right, however, to require verification of welders' qualifications when deemed necessary. Such verification may include testing prior to production, extra NDT and/or welding production tests.

Ch.3 Sec.1
B 600   Corrosion protection systems

Ch.3 Sec.1 B
601   Application of coating, steel surface preparation with respect to application of coating and fabrication and installation of sacrificial anodes and impressed current cathodic protection systems are not included in DNV's scope of work unless upon special agreement.

Ch.3 Sec.1
B 700   Non-destructive testing

Ch.3 Sec.1 B
701   Subcontractors engaged in NDT services for newbuildings shall be approved in accordance with Standard for Certification No. 2.9 Approved Programme No. 402B.

Ch.3 Sec.1
C. Records and Documentation

Ch.3 Sec.1
C 100   General

Ch.3 Sec.1 C
101   Adequate records related to the fabrication of the structure shall be prepared to document that the structure meets the specified requirements. Such records shall be compiled in parallel with the fabrication process. Compiled records shall be systematic and fully traceable. Such records shall reflect all relevant testing, alterations, additions, corrections and revisions made during the fabrication period in order to provide information required during the in- service life of the structure.
Sec.6: Miscellaneous [Table of Contents]