DNV-OSS-312: Certification of Tidal and Wave Energy · PDF file102 The wave and tidal energy converters being installed offshore as well as inshore will be faced with many

OFFSHORE SERVICE SPECIFICATION

The electronic p

DNV-OSS-312

Certification of Tidal and Wave Energy Converters

OCTOBER 2008

This document has been amended since the main revision (October 2008), most recently in April 2012. See “Changes” on page 3.

DET NORSKE VERITAS AS

df version of this document found through http://www.dnv.com is the officially binding version

FOREWORD

DET NORSKE VERITAS (DNV) is an autonomous and independent foundation with the objectives of safeguarding life,property and the environment, at sea and onshore. DNV undertakes classification, certification, and other verification andconsultancy services relating to quality of ships, offshore units and installations, and onshore industries worldwide, andcarries out research in relation to these functions.

DNV service documents consist of amongst other the following types of documents:— Service Specifications. Procedual requirements.— Standards. Technical requirements.— Recommended Practices. Guidance.

The Standards and Recommended Practices are offered within the following areas:A) Qualification, Quality and Safety MethodologyB) Materials TechnologyC) StructuresD) SystemsE) Special FacilitiesF) Pipelines and RisersG) Asset OperationH) Marine OperationsJ) Cleaner EnergyO) Subsea Systems

© Det Norske Veritas AS October 2008

Any comments may be sent by e-mail to [email protected] subscription orders or information about subscription terms, please use [email protected] Typesetting (Adobe Frame Maker) by Det Norske Veritas

This service document has been prepared based on available knowledge, technology and/or information at the time of issuance of this document, and is believed to reflect the best ofcontemporary technology. The use of this document by others than DNV is at the user's sole risk. DNV does not accept any liability or responsibility for loss or damages resulting fromany use of this document.

Amended April 2012 Offshore Service Specification DNV-OSS-312, October 2008see note on front cover Changes – Page 3

CHANGES

Amendments April 2012

— The restricted use legal clause has been deleted from the front page.

Amendments October 2011

— A restricted use legal clause has been added on the front page.


Offshore Service Specification DNV-OSS-312, October 2008 Amended April 2012Page 4 – Contents see note on front cover

CONTENTS

Sec. 1 Introduction ........................................................................................................................................ 6

A. Introduction................................................................................................................................................................... 6A 100 General.................................................................................................................................................................. 6A 200 Organisation of this Offshore Service Specification ............................................................................................ 6A 300 Objects covered..................................................................................................................................................... 6A 400 DNV Document hierarchy .................................................................................................................................... 6

B. Definitions ...................................................................................................................................................................... 7B 100 Verbal forms ......................................................................................................................................................... 7B 200 Definitions ............................................................................................................................................................ 7

C. References ...................................................................................................................................................................... 8C 100 DNV documents ................................................................................................................................................... 8C 200 International standards ........................................................................................................................................ 10

D. Safety Philosophy ........................................................................................................................................................ 10D 100 General Considerations....................................................................................................................................... 10D 200 Structures ............................................................................................................................................................ 10D 300 Equipment and Systems...................................................................................................................................... 11

E. Certification Deliverables.......................................................................................................................................... 11E 100 Deliverables ....................................................................................................................................................... 11

Sec. 2 Principles and Process ..................................................................................................................... 14

A. Principles of Certification ......................................................................................................................................... 14A 100 Introduction......................................................................................................................................................... 14A 200 Certification Approach........................................................................................................................................ 14A 300 Scope of Certification ........................................................................................................................................ 15

B. Qualification of New Technology............................................................................................................................... 16B 100 General................................................................................................................................................................ 16B 200 Basis for the qualification of new technology .................................................................................................... 16B 300 Qualification process ......................................................................................................................................... 16B 400 Establishment of reliability ................................................................................................................................ 17B 500 Testing ................................................................................................................................................................ 18B 600 Deliverables from the Qualification process....................................................................................................... 18B 700 Reference ............................................................................................................................................................ 18

C. Procedures for Assignment of Certification ............................................................................................................ 19C 100 Request for certification...................................................................................................................................... 19C 200 Standards............................................................................................................................................................. 19C 300 Requirements for workshops and yards.............................................................................................................. 19C 400 Information about subcontractors and suppliers of products.............................................................................. 19C 500 Requirements for manufacturers......................................................................................................................... 19C 600 Requirements for suppliers of services ............................................................................................................... 19C 700 Document requirements ...................................................................................................................................... 19C 800 Survey ................................................................................................................................................................. 20C 900 Functional testing................................................................................................................................................ 20C 1000 Final Certification Documentation ..................................................................................................................... 20C 1100 Maintenance of Certificate – In-service Requirements ...................................................................................... 20C 1200 Other conditions.................................................................................................................................................. 21

D. Verification of Procured Items ................................................................................................................................. 21D 100 General................................................................................................................................................................ 21D 200 Case-by case approval......................................................................................................................................... 21D 300 Type approval .................................................................................................................................................... 22D 400 Documentation of Certification .......................................................................................................................... 22D 500 Manufacturing survey arrangement .................................................................................................................... 23

Sec. 3 Documentation.................................................................................................................................. 24

A. General ......................................................................................................................................................................... 24A 100 Typical documentation and type of service ........................................................................................................ 24

B. Structural design ........................................................................................................................................................ 24B 100 Type of installation ............................................................................................................................................. 24B 200 Environmental data ............................................................................................................................................. 24B 300 Floating Tidal and Wave Energy Converters ..................................................................................................... 24B 400 Fixed Tidal and Wave energy converters ........................................................................................................... 25

C. Position keeping........................................................................................................................................................... 25C 100 General................................................................................................................................................................ 25


Amended April 2012 Offshore Service Specification DNV-OSS-312, October 2008see note on front cover Contents – Page 5

D. Machinery and Marine Systems ............................................................................................................................... 25D 100 Floating Installations........................................................................................................................................... 25

E. Electrical systems ........................................................................................................................................................ 26E 100 General................................................................................................................................................................ 26

F. Instrumentation and control systems ....................................................................................................................... 26F 100 General................................................................................................................................................................ 26

G. Fire protection and safety systems ............................................................................................................................ 26G 100 General................................................................................................................................................................ 26


Offshore Service Specification DNV-OSS-312, October 2008 Amended April 2012Page 6 – Sec.1 see note on front cover

SECTION 1INTRODUCTION

A. Introduction

A 100 General101 This Offshore Service Specification presents the principles and procedures for DNV services withrespect to Certification of tidal and wave energy converters.102 The wave and tidal energy converters being installed offshore as well as inshore will be faced with manyof the same environmental challenges as oil and gas installations being installed offshore. To mitigate the risksrelated to the lack of operational experience in the offshore renewable industry, DNV will use its experiencefrom the oil and gas industry duly adapted to the relevant safety levels necessary for renewable energyinstallations. Reference is therefore extensively given to our offshore standards and recommended practices aswell as international standards.103 Due to the specific needs and characteristics of this industry, the certification concept is extended suchthat it can be defined as a robust process to provide, through independent verification, evidence to stakeholders(financiers, partners, utility companies, insurers and the public) that the marine energy converter will performadequately within acceptable levels of safety, availability, reliability, asset integrity and environmental impact,within limits specified in the certification basis and complying, where applicable, to relevant standards.

A 200 Organisation of this Offshore Service Specification201 This document is divided into the main sections:

— Section 1 provides a general introduction to the DNV document hierarchy— Sections 2 and 3 describe the principles and procedures for the certification services.

A 300 Objects covered301 All different concepts of tidal and wave energy converters are covered. This document refers primarilyto offshore and near shore concepts for tidal and wave energy converters, but it may also be used for shorelinedevices. 302 The converters may be of fixed or floating type. They may be constructed in steel, concrete or composite.303 This Offshore Service Specification (OSS) is general and flexible in order to match the large differencesin technology and concepts being developed in the renewable energy industry. The OSS gives a framework forhow the certification is applied to the marine renewable industry.

A 400 DNV Document hierarchy401 DNV Offshore Publications which provide information at various levels of detail for offshoreinstallations are organized into a three level document hierarchy, illustrated in Figure 1:

— Offshore Service Specifications (OSS series) providing principles and procedures of certification,classification, verification and consultancy services

— Offshore Standards (OS series) specifying technical requirements and acceptance criteria for general useby the offshore industry as well as providing the technical basis for classification. (For wave energyconverters DNV refers to “Guidelines on design and operation of wave energy converters” a documentcommissioned by Carbon Trust and carried out by DNV, May 2005. The Carbon Trust is an independentcompany funded by the UK Government. Its role is to help the UK move to a low carbon economy byhelping business and the public sector to reduce carbon emissions now and capture the commercialopportunities of low carbon technologies.)

— Recommended Practices (RP series) providing sound engineering practice as well as guidance related tothe Offshore Standards.


Amended April 2012 Offshore Service Specification DNV-OSS-312, October 2008see note on front cover Sec.1 – Page 7

Figure 1 DNV Offshore Publications Hierarchy

B. Definitions

B 100 Verbal forms101 The terms will, can and may are used when describing DNV’s actions or activities, and the terms shall,should and may are used when referring to other parties than DNV.

102 “Shall”: Indicates requirements strictly to be followed in order to conform to this OSS and from whichno deviation is permitted.

103 “Should”: Indicates that among several possibilities, one is recommended as particularly suitable,without mentioning or excluding others, or that a certain course of action is preferred but not necessarilyrequired. Other possibilities may be applied subject to agreement.

104 “Will”: Indicates a mandatory action or activity to be undertaken by DNV. (Ref. “shall” for otherparties).

105 “Can”: Indicates an action or activity that DNV will not necessarily do unless specifically requested bythe client (Ref. “should” for other parties).

106 “May”: Verbal form used to indicate a course of action permissible within the limits of the OSS.

B 200 Definitions201 Client: DNV’s contractual partner. It may be the purchaser, the owner or the contractor.

202 Certification: Action by a certification body, providing written assurance that adequate confidence isprovided that a duly identified product is demonstrably in conformity with a specific standard or othernormative document.

203 Certification Basis: Requirements for the system’s specifications, operating conditions, performancetargets and reliability targets. The basis to which the system will be assessed during certification.

204 Conceptually feasible: A technology at an early stage of development is considered conceptually feasibleif the main challenges have been identified and judged to be resolvable by use of sound engineering practice.

Guidance note:Although a technology has been stated conceptually feasible, there are still activities necessary to be executed in orderto prove that the technology is fit for service. Consequently, there will be a possibility that the technology, contraryto expectations, will not be stated fit for service.

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205 Failure: Termination of the ability of an item to perform the required (specified) function.

206 Fit for service: A technology is considered fit for service when the failure modes that have beenidentified through the systematic process outlined in this OSS have been properly addressed, and the supportingevidence substantiates that the technology fulfils all stated functional requirements and meets the statedreliability target.

DNV OFFSHORESTANDARDS

OTHER

DNV STA

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RDS

DNV OFFSHORE

SERVICESPECIFICATIONS.

DNV GUIDELINES

& NOTESDNV RECOMMENDED PRACTICES

TECH

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PROC

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INTERNATIONAL CO

DES/STANDARDS

INTERNAT.RPs ETC.



Guidance note:Although a technology has been stated fit for service, the technology has not necessarily an in-service record thateliminates the possibility for failures due to unidentified or misjudged failure modes. Consequently, there will be apossibility that the technology, contrary to expectations, will fail in-service.


207 New technology: Technology that is not proven. This implies that the application of proven technologyin a new environment or an unproven technology in a known environment, are both new technology. Thedegree of new technology will be classified in categories to be used as input to risk assessment.

208 Prototype: An original type that serves as a model for later models, and allows for testing andimprovement of the design.

209 Proven technology: In the field, proven technology has a documented track record for a definedenvironment. Such documentation shall provide confidence in the technology from practical operations, withrespect to the ability of the technology to meet the specified requirements.

210 Risk: The qualitative or quantitative likelihood of an accident or unplanned event occurring, consideredin conjunction with the potential consequences of such a failure. In quantitative terms, risk is the quantifiedprobability of a defined failure mode times its quantified consequences.

211 Risk reduction measures: Those measures taken to reduce the risks to the operation of the technologyand to the health and safety of personnel associated with it or in its vicinity by:

— reduction in the probability of failure— mitigation of the consequences of failure.

212 Surveillance: The process of inspecting tests, calibrations or other activities to assure that the necessaryquality is maintained. Once the device is in operation, reviews carried out to assure that operation is withinsafety limits, and is maintained within limiting conditions.

213 Technology qualification: A confirmation by examination and provision of evidence that the newtechnology meets the specified requirements for the intended use. Hence, qualification is a documented set ofactivities to prove that the technology is fit for service.

214 Verification: An examination to confirm that an activity, a product or a service is in accordance withspecified requirements.

C. References

C 100 DNV documents

101 This document will make reference to relevant documents in the DNV document hierarchy and whereappropriate to internationally accepted publications, codes and standards.

102 The Offshore Standards listed in Table 1 shall be used for documentation of tidal and wave energydevices. The Recommended Practices and Class Notes listed in Table 2 shall be used. Only those DNVstandards and recommended practices that are assumed to be relevant for energy converters are listed in Table1 and Table 2. Reference is also made to the Guidelines on Design and Operation of Wave Energy Converters(Commissioned by Carbon Trust, and carried out by DNV May 2005).

Table 1 DNV Documents relevant for Tidal and Wave Energy Converters Reference Title

DNV-OSS-121 Classification based on performance criteria determined from risk assessment methodology

DNV-OSS-300 Risk-based verification

DNV-OSS-401 Technology qualification management

DNV-OS-A101 Safety principles and arrangement

DNV-OS-B101 Metallic materials

DNV-OS-C101 Design of offshore steel structures, general (LRFD method)

DNV-OS-C102 Structural design of offshore ships

DNV-OS-C103 Structural design of column-stabilised units (LRFD method)

DNV-OS-C104 Structural design of self-elevating units (LRFD method)

DNV-OS-C105 Structural design of TLPs (LRFD-method)

DNV-OS-C106 Structural design of deep draught floating units (LRFD method)

DNV-OS-C301 Stability and watertight integrity

DNV-OS-C401 Fabrication and testing of offshore structures



DNV-OS-C501 Composite components

DNV-OS-C502 Offshore concrete structures

DNV-OS-D101 Marine and machinery systems and equipment

DNV-OS-D201 Electrical installations

DNV-OS-D202 Instrumentation and telecommunication systems

DNV-OS-D301 Fire protection

DNV-OS-E301 Position mooring

DNV-OS-F201 Dynamic risers

DNV-OS-J101 Design of offshore wind turbine structures

DNV-OS-J102 Design and fabrication of wind turbine blades

DNV Rules Rules for planning and execution of marine operations

Table 2 DNV Recommended Practices, Classification Notes and Standards for CertificationReference Title

DNV-RP-A203 Qualification procedure for new technology

DNV-RP-B401 Cathodic protection design

DNV-RP-C102 Structural Design of Offshore ShipsDNV-RP-C103 Column Stabilised UnitsDNV-RP-C201 Buckling strength of plated structures

DNV-RP-C202 Buckling strength of shells

DNV-RP-C203 Fatigue analysis strength of offshore steel structures

DNV-RP-C204 Design against accidental loads

DNV-RP-C205 Environmental conditions and environmental loadsDNV-RP-C206 Fatigue methodology of offshore shipsDNV-RP-C207 Statistical representation of soil dataDNV-RP-E301 Design and installation of fluke anchors in clayDNV-RP-E302 Design and installation of plate anchors in clay

DNV-RP-E303 Geotechnical design and installation of suction anchors in clay

DNV-RP-F205 Global performance analysis of deepwater floating structures

DNV-RP-H101 Risk management in marine and subsea operations

Standards for certification

No. 2.4 Environmental test specification for instrumentation and automation equipment

No. 2.5 Certification of offshore mooring steel wire ropes

No. 2.6 Certification of offshore mooring chains

No. 2.9 Approval Programmes – related to components (incl. e.g. hydraulic cylinders), manufacturers, service suppliers. (Freely downloaded from our website: exchange.dnv.com)

No. 2.13 Standard for certification of offshore mooring fibre rope

Classification Notes

CN 30.4 Foundations

CN 30.6 Structural reliability of marine structures

CN 30.7 Fatigue assessment of ship structures

CN 33.1 Corrosion prevention of tanks and holds

CN 41.2 Calculations of gear rating for marine transmissions

CN 41.4 Calculations of shafts in marine applications for marine transmissions

CN 45.1 Electromagnetic compatibility

Guidelines and recommended practices

No. 20 Corrosion protection of ships

Table 1 DNV Documents relevant for Tidal and Wave Energy Converters (Continued)Reference Title



The majority of the above documents in the DNV hierarchy may be accessed via DNV’s website: http://webshop.dnv.com/global/

C 200 International standards

201 Internationally recognised standards may also be used in design and construction of tidal and waveenergy converters.

D. Safety Philosophy

D 100 General Considerations

101 Targets for the certification process and the certification basis, should be based on an overall safetyphilosophy covering all phases from conceptual studies up to and including decommissioning.

102 A safety philosophy should be derived considering the following aspects and stakeholders:

— risk to life (during installation and removal, access to device during in-service life, risk to navigation andothers during in-service life)

— environmental impact due to any fluid releases, anti-fouling coatings, bilge water, and location of siterelative to sensitive environments (protected species or sensitive sites and visual impacts)

— loss of power generation — inspection and maintenance cost, risks during removal of equipment for inspection and maintenance— reputation of developer, industry, concept (survivability of the device in extreme conditions is very

important in terms of reputation)— underwriter perception of risks and definition of premium value (during installation and removal, and in-

service life)— financial or venture capital communities’ perception of risk to the return on investment— safety level expected by Authorities. This may include Authority requirements in other countries which are

potential marketing targets for the devices.

103 In general, when selecting safety level, safety classes can be defined as:

Safety Level Low – where failure implies low risk of human injury and minor environmental and economicconsequences.

Safety Level Normal – for temporary conditions where failure implies risk of human injury, significantenvironmental pollution or high economic, asset damage or political consequences. This level normally aimsfor a risk of less than 10-4 per year of a major single accident, which corresponds to a major incident happeningon average less than once every 10 000 installation years. This level equates to the experience level from majorrepresentative industries and activities.

Safety Level High – for operating conditions where failure implies high risk of human injury, significantenvironmental pollution or very high economic or political consequences.

Guidance note:It may be useful to specify separate target levels for Safety, Environmental, Asset and Operational risks.


D 200 Structures

201 The requirements for wave energy devices can be covered in large parts by codes for offshore steelstructures as in DNV-OS-C101 (DNV-OS-C501 for composite components and DNV-OS-C502 for concretestructures). These provide internationally acceptable levels of safety by defining minimum requirements forstructures and structural components.202 DNV-OS-C501 is a comprehensive and generic design and fabrication code for structures andcomponents using composite materials (laminate or sandwich).203 DNV-OS-C502 is particularly adequate to wave energy conversion (WEC) devices that consider the useof concrete as the ratio between wave responses and dead load response will generally be high. In this loadsituation, most other standards are not applicable. For offshore concrete structures this especially applies tofatigue calculations. DNV-OS-C502 is in fact very similar to NS3473 (which would be equally applicable toWEC devices) except for some areas. The most important difference is fatigue Wøhler curves forreinforcement.204 In DNV-OS-C502 the results of a British research project “Concrete in the Ocean” are implemented andthese Wøhler curves are stricter than the Wøhler curves in NS3473 and in the Eurocode. NS3473 and Eurocodebase their fatigue curves on reinforcements not exposed to a marine environment, i.e. no corrosion fatigue.

205 The load response part of DNV-OS-C502 is very similar to the draft ISO code (ISO/DIS 19903) foroffshore concrete structures. This code may also be an alternative once it is finally agreed.



206 For temporary phases (e.g. installation or removal), requirements are given in the DNV Rules forPlanning and Execution of Marine Operations. This uses a somewhat higher probability of failure whencompared to requirements for in-place survival condition, as these marine operations can be characterised bysingle event operation with implementation of special procedures and better control of environmental limits,etc. DNV-RP-H101 provides guidance and recommendations on how to reach an acceptable and controlledexposure to risk during marine operations for personnel, environment, assets and reputation.207 The consideration of selected safety class can be taken into account for some aspects of the structuraldesign such as: the definition of Design Fatigue Factor, derivation of characteristic loads, definition of loadfactors to be applied (see DNV-OS-C101 Sec.2 D404), definition of accidental loading (see DNV-OS-A101Sec.2 D103) and selection or structural category (DNV-OS-C101 Sec.4 C200 – taking into account thesignificance of components in terms of consequence of failure).

D 300 Equipment and Systems301 Safety classes shall be considered while defining redundancy or safety features for the equipment andsystems. Reliability is also an important aspect to be taken into account.302 Because wave and tidal energy devices are usually unmanned, the overall risk level to personnel will below. However, because of the difficulty in access for maintenance and the potential penalty of downtime interms of providing energy to the grid, a higher level of reliability may be required than would otherwise be thecase.303 To obtain such a level of reliability, with limited or non-existent reliability data for marine renewableconditions and through the use of standard off-the-shelf equipment, where it is possible, requires earlyconsideration of strategies leading to reliability/availability required and maximum level possible ofmaintenance and repair. Some examples of such strategies are given below:

— a low utilisation of mechanical strength, or a higher reserve, sometimes referred to as the safety factor isemployed

— redundancy of equipment – this is usually applicable to electronic and moving parts— rigorous testing of moving parts subject to cyclic loads— rigorous testing of components subject to various environmental loads— use of well-proven components— a thorough FMEA study.

E. Certification Deliverables

E 100 Deliverables 101 The final conclusion from the certification will be documented by a specific agreed deliverable. Thedeliverables indicate the incremental nature of the certification process with each stage contributing to the nextstep. The deliverables provide for the gradual increase in detail and scope from the concept stage through tocertification of a fully developed product. Typically these deliverables will be termed as follows:102 Reports:

— Statement of Feasibility — Design Assessment— Product Certificates for Components and Assemblies— Survey Reports — Certificates:

In order to account for the different stages in the development of the device DNV may issue the followingcertificates:

— DNV Prototype Certificate— DNV Conditioned Type Certificate— DNV Type Certificate— DNV Project Certificate.



Figure 2 DNV Certification Process

103 Statement of Feasibility - A document issued by DNV affirming that, at the time of assessment, the newtechnology is considered conceptually feasible and suited for further development and qualification accordingto the principles outlined in DNV-RP-A203.

104 Design Assessment – During the design assessment stage, intermediary deliverables such as letters withcomments and reports should be issued indicating progress and identifying gaps in the information providedby the Applicant. The conclusion of the design assessment process should be documented by a Statement ofDesign Assessment.

105 Product Certificates for Components and Assemblies – Certificates issued by DNV regarding differentcomponents including design appraisal, manufacturing surveillance and factory acceptance testing.

106 Survey Reports – Reports issued by DNV surveyor addressing the issues related to surveillance activitythat may cover different stages such as manufacturing, testing, commissioning and installation.

107 Prototype Certificate

Certificate issued to enable testing of prototypes and is based on design evaluation. This certificate implies thatall the certification steps up to the issue of this certificate were successfully carried out (statement of feasibility,design assessment, fitness for purpose and manufacturing surveillance) for the specified location/conditions.

Project Initiation

Design Assessment

Product Certificates for Components and Assemblies

Survey Reports

DNV Prototype Certificate

DNV Type Certificate

DNV Project Certificate

DNV Conditioned Type Certificate

DNV Statement of Feasibility



The location of the device is stated on the certificate and the period of validity is limited up to 3 years. The issueof the Prototype Certificate is based on successful evaluation by DNV of:

— prototype design, including installation procedures— prototype fabrication surveillance— installation surveillance— final acceptance/commissioning inspection— periodic inspection.

During the prototype design evaluation, matters with no safety implication within the period of validity can beconsidered at a higher level with the use of simplified methods (sufficient to demonstrate that the risk ofsignificant damage to structure and equipment is minimised), pending operational data from the prototype andany resulting design changes. Those issues will be assessed based on existing knowledge and with uncertaintiesto be clarified, under controlled circumstances, during the prototype test stage. Items including safety concept,support structure and mooring system shall be analysed in detail.108 Conditioned Type CertificateThe Conditioned Type Certificate is issued to allow for 0-series production as well as to allow for outstandingmatters with no safety implication. The Conditioned Type Certificate is based on full certification scope withthe exception that outstanding matters are allowed. The outstanding matters are however limited to:

— matters with no safety implication within the period of validity (maximum 1 year)— matters related to the finalization of manuals and quality control procedures— matters related to the finalisation of inspections regarding the implementation of the design-related

requirements in production and installation.

Provisions can be made for upgrade of Conditioned Type Certificate to Type Certificate for a particular device,subject to conditions agreed between the Applicant and DNV.109 Type CertificateThe Type Certificate is issued for production model with no outstanding issues (validity of 5 years subject toannual endorsement).110 Project CertificateWithin the Project Certification scope it will be assessed whether the metocean conditions, other environmentaland electrical network conditions, and soil properties at the site conform with those defined in the designdocumentation for the energy converter. Any additional site specific designs and/or design changes related tothe energy converter are considered within the Project Certification. These in general include foundations,support structure and moorings. The Project Certificate includes the design, manufacturing, installation andcommissioning of the wave/tidal farm including cable laying and additional structures required for the transportand connection of the farm to the grid or the consumer.111 These documents/certificates will make reference to the standards, regulations and other specificationswhich have formed the basis of the certification, and will be backed up by a traceable record documenting theinformation considered and the considerations made in arriving at the final status of the verification work.112 Qualification and testing of new technology will be documented separately. See also Sec.2 B600.



SECTION 2PRINCIPLES AND PROCESS

A. Principles of Certification

A 100 Introduction

101 Certification is a comprehensive service providing assurance that a set of requirements laid down instandards are met during design and construction, and maintained during operation of an energy converter.Certification has gained world-wide recognition as representing an acceptable level of safety and quality.

102 Certification implies an activity in which an energy converter is surveyed by DNV during constructionon the basis of design approval, tested before being taken into service, and surveyed regularly during its wholeoperational life. The aim is to verify that relevant requirements are built-in, observed and maintained.

103 The certification shall be documented by a set of specific, agreed deliverables and certificates.

104 In order to maintain the Certificate the converter needs to be satisfactorily maintained and modificationsadequately addressed. This is confirmed by annual and periodic surveys.

105 The principles and procedures outlined in this OSS aim at implementing certification complying with theaspects above and in line with marine renewable certification as defined in Sec.1 A103.

A 200 Certification Approach

201 Designs of tidal and wave energy converters may typically contain important subsystems for which thereis no relevant service history. These systems, loads and load structural interaction effects may not be adequatelyaddressed by existing codes or standards.

202 In order to overcome this shortcoming in the Certification process, DNV has developed a Qualificationapproach to be used for the parts of the technology where little or no experience exists, or where proventechnology is used in new applications. For the remaining parts of the technology more traditional certificationactivities may be applied, see Figure 1.

203 The evaluation of new versus proven technology is performed according to the systematic illustrated inFigure 1. This assessment has to be performed at the level of detail necessary to separate proven from newtechnology as parts of the subject subsystems may be arranged together with known as well as unproventechnologies.

The classification in Figure 1 implies the following:

1) No new technical uncertainties

2) New technical uncertainties

3) New technical challenges

4) Demanding new technical challenges.

Proven technology is considered technology classified as 1 No new technical uncertainties.

204 All systems and aspects should be considered, see also A300.

205 The recommended certification systematic is shown in Figure 2. New technology (rating 2-4) will besubject to qualification and proven technology (rating 1) will be subject to traditional certification.

206 Proven technology shall be documented in accordance with standards and recommended practices, seeTable 1 and Table 2, and relevant international standards. Further description of the certification is given inSub-section C. The qualification process is outlined in Sub-section B.

Figure 1 Technology assessment according to DNV-RP-A203

1: Proven technology 2 - 4: New Technology

Application Area1

Proven2

Limited field history3

New or unproven

1. Known 1 2 3

2. New 2 3 4

Technology status

Application Area1

Proven2

Limited field history3

New or unproven

1. Known 1 2 3

2. New 2 3 4

Technology status



Figure 2 Certification approach

207 The approach for second and successive generation converters will be the same as the approach for noveldesigns. However, the number of “new technology” items is assumed to be less than for the original qualifieddesign as experience is gained from previous loops on the qualification process/qualification methods appliedand through the operation of the prototype/pilot unit(s).

A 300 Scope of Certification 301 Typical scope for certification of tidal or wave energy converters comprises the in-place condition forthe following systems:

— Load and response analyses (the control system may have significant effect on the global behaviour)— Structures— Mooring system— Electrical system— Mechanical system— Hydraulic system— Control system— Safety systems incl. emergency shutdown system— Marine systems including bilge system— Other systems such as: turbines, pitch, lubrication, dehumidification, cooling systems, corrosion

protection, etc— Power measurement— Maintenance procedures.

302 Temporary phases, such as installation, float-out, lifting, transportation, etc, are also part of thecertification scope from the point of view that the operations should not affect the feasibility of the concept, theintegrity of the energy converter or in any aspect that reflects on the operation, maintenance and repair issues.303 A detailed description of necessary documentation for a final certificate is outlined in Section 3.

304 The inclusion of power take-off performance in the certification scope may be carried out by review,auditing and certification of the process used to measure the power take-off and its integrity. The scope will

Meet Qualification Basis?

Technology

Certification (Sect.3)

New TechnologyNew Technology

Define Qualification Basis

Technology Assessment

Failure Mode Identificationand Risk Ranking

Concept Improvement

Selection of Qualification

Methods

Probability of Success Evaluation

Analysis and Testing

Reliability Assessment

Tidal and WaveEnergyConverterCertificate

ProvenTechnology



depend on the level of certification of power take-off required. This can vary from certification of completepower curves and general model law to confirmation of maximum power generated to specific environmentalconditions. Where available, standards for power measurement may be applied.

305 The following main principles should be observed regarding power take-off certification:

— Power take-off measurements should be sufficient to allow for calibration of analytical model in order thatthe analytical model should also be able to predict, within a reasonable level of certainty, the power take-off for different meteocean conditions and site characteristics than those investigated.

— The period of time dedicated for evaluation of power take-off should be defined to allow for the relevantmeteocean conditions to be recorded and provide the necessary statistical data.

— The main parameters investigated for power take-off measurements are identified and described from thepoint of view of the device application.

— Extrapolation of results will need to be based on trends manifested during measurements.— Reference should be made to any limitations on the measurement process, field characteristics, meteocean

conditions (e.g. sea states, currents) measurement at site and level of uncertainty that may affect the overallpower take-off calculations. The level of availability assumed and quality of output should also be referredto.

B. Qualification of New Technology

B 100 General

101 As qualification is an important part of the certification process, this section summarises the main aspectsof the “Qualification of New Technology” and how it is applied in the context of marine renewable energysources.

102 The objective of a qualification procedure is to ensure that the technology functions reliably withinspecified limits. The approach developed by DNV and described in this section provides a rational qualificationphilosophy and, by focusing on a balanced use of reliability, ensures a cost effective implementation oftechnology and an increase in the level of confidence. Sensible input may then be provided to the overall riskassessment of the concept.

The main features of a qualification approach are described below.

B 200 Basis for the qualification of new technology

201 The qualification must be based on specified performance limits, boundary conditions and interfacingrequirements defined in the certification basis.

B 300 Qualification process

301 The reliability goals specified for the certification should be based on the business plan for the system.These goals should be specified in the certification basis. The procedure will specify the philosophies,principles and methods to be used in the qualification process. At each step of the process there is a need fordocumentation making the process traceable. The qualification process should comprise the following mainactivities:

— Establish an overall plan for the qualification. This should be a continuous process and needs updating aftereach step using the available knowledge on the status of the qualification.

— Establish a certification basis comprising functional, safety and environmental targets for the device.Define the functionality and limiting operating parameters for the new technology.

— Screen the technology based on assumed loadings, identification of failure modes and their risk, andclassification of the technology in terms of degree of novelty to focus the effort where the relateduncertainty is most significant.

— Assess maintenance, condition monitoring and possible concept modifications to reduce the risk. — Plan and execute reliability data collection. The data is used to analyse the risk of not meeting the

specifications through experience, numerical analysis and tests. — Analyse the reliability of the new technology, and thereby the risk of the failure modes related to the

functional requirements of the new technology.

These logical steps in the qualification process are combined and visualised in groups in Figure 3. The resultsfrom one step are the input to the next step.



Figure 3 Main qualification activities

302 There will be feedback loops between the steps so that results that lie outside the specified limits can leadto a design modification, specification modification or maintenance plan modification.

B 400 Establishment of reliability 401 The qualification process can be run throughout the whole development of the new technology, or bestarted at any time in the development. Figure 4 illustrates that the failure probability at the service life targetis reduced through the qualification work until a remaining failure probability is concluded.

Figure 4 Illustration of the qualification process.

402 In principle, qualification is considered completed when the acceptance percentile crosses the target levelfor the service life. A qualitative approach can be practical to use in the early development phase (conceptualphase). Quantitative measures may be relevant in the later development phase.

Technology

Define Qualification Basis

Failure Mode Identification

and Risk Ranking

Analysis and Testing(Data Collection / DesignApproval / Surveillance)

Functionality Assessment

Concept Improvement

Selection of Qualification

MethodsStatement ofFeasibility

Technology Assessment

Use of Codes andStandards

Failure Mode Identification

+ Recommendations from Guidelines+

Class?

1 & 2

3 & 4

RiskRanking

Class 1 & 2

Yes

No

2

Certificate ofFitness forService

Make Decisions

Specific Recommendations for Tidal



B 500 Testing501 The analytical approach should be supported and complemented by results obtained from testing tohandle the uncertainties in the technology. Tests as described below are used for materials, components, sub-assemblies and assemblies. The typical tests are termed:

— Basic tests, such as testing of material properties and degradation mechanisms. — Prototype tests (qualification tests) of components, sub-assemblies and assemblies verify the functional

requirements of a new type design. Prototype tests can be carried out in phases including laboratory tests,and various degrees of environmental and full service tests (pilot test).

— Factory acceptance tests (FAT), of sub-assemblies and assemblies verify the manufacturing and assemblyof a system, which is already prototype tested.

— Model basin tests, testing of global response of device in survival and operational conditions. The testingof the operational condition shall include testing of the control system.

— Simulation of the interaction between the control system and the structural behaviour. — Pre and post installation tests, of the full assembly verify the soundness prior to and after the completed

installation. All possible systems should be tested prior to transportation to site.

502 The prototype/pilot application represents the first use, and is therefore normally regarded as anadvanced test to gain more experience with the system, ensuring that all aspects of a complex system have beentaken into account. Prototype/pilot testing is normally necessary to determine the forces at and response of thestructure, to test functionality and control systems and obtain data regarding the performance of equipmentduring power generation.

B 600 Deliverables from the Qualification process601 The deliverables from the Qualification and testing of new technology includes the following statementsfor the selected components and systems:

— Statement of Feasibility— Certificate of Fitness for Service

602 The statements will be supported by technical reports giving the assumptions and conditions of thestatements, see also Figure 3.603 The end result of the “Qualification of New Technology” shall be documentation of Fitness for Servicefor the considered systems, applying relevant approaches. The “Fitness for Service” certificate may also be partof the basis of the certification of the next generation converter.

B 700 Reference701 For more detailed information on the qualification methodology, reference is made to DNV-OSS-401“Technology Qualification Management” and to DNV-RP-A203 “Qualification Procedures for NewTechnology” for applicable procedures.

Table 3 Recommended testing for some selected systems and components 1)

SystemModel tests

Factory acceptance

testSimulation Pre and post

installation tests Pilot test

Components performance XLoading & response X X XGlobal response and interaction with power take-off system/Power Performance

X2) X2)

Control system X X X XPower take-off system X X X XEmergency shut down system X X XComplete installation X X1) The extent of testing shall be evaluated in each separate case

2) The global motions and response analyses should be validated against actual test results.



C. Procedures for Assignment of Certification

C 100 Request for certification

101 A request for certification shall be submitted in writing by the client.

C 200 Standards

201 The basis of certification will be compliance with the standards listed in Table 1, other relevantinternational standards and the Technology Qualification Report developed for the new technology elementsunless otherwise agreed with the client. The standards to be used shall be agreed between DNV and the Clientat the beginning of the Design Assessment stage.

202 Please note the discussion concerning challenges in using related standards and parts of standards for anovel application in A200.

Guidance note:Existing codes and standards can be directly applied to areas identified as “proven technology” (Class 1). For Class2, it may still be possible to apply codes and standards provided that the Qualification process is carried out in orderto identify any possible failure mode that it is not covered by the code and standard and any additional activity to becarried out to cover the new failure modes. For Class 3 and 4 the Qualification process is expected to be fully applied.


C 300 Requirements for workshops and yards

301 Clients shall operate a quality management system applicable to the scope of their work. The system shallbe documented and contain descriptions and procedures for quality critical aspects. Clients shall demonstratetheir capability to carry out fabrication of adequate quality in accordance with the relevant standards, and withany additional requirements based on criticality of processes, before construction is started.

302 Welding of important structures, machinery installations and equipment shall be carried out by qualifiedand approved welders to qualified and approved weld procedures, with approved welding consumables and atwelding shops accepted by DNV.

303 During fabrication and construction work, DNV surveyors shall have safe access to the works at allreasonable times, insofar as the work affects certification. The client shall ensure, through contracts with theparties concerned or otherwise, that such access is possible, and that DNV is notified as to when and where thesurveyor's attendance is needed.

C 400 Information about subcontractors and suppliers of products

401 The following documentation from the Client (workshop) and from subcontractors shall be submitted toDNV at the start of a certification project:

— list of subcontractors to the workshop— list of suppliers of materials and components, including subcontractors if applicable— quality plan.

It is expected that subcontractors’ Quality Management System are certified by an accredited certificationbody.

C 500 Requirements for manufacturers

501 Manufacturers of materials, components and equipment shall be approved according to criteriaestablished by DNV, as applicable (defined in the respective standards or from the Qualification process).

502 Any required quality control of materials, components and equipment, shall be traceable anddocumented in writing. Further, quality control shall be carried out by qualified personnel at facilities and withequipment suitable for that control.

C 600 Requirements for suppliers of services

601 Firms providing services on behalf of the owner, such as measurements, tests and maintenance of safetysystems and equipment, where the results may form the basis for the surveyor's decisions, shall be approved byDNV.

602 Measuring and test equipment used in services by manufacturers, builders, repairers or owners, wherethe results may form the basis for the surveyor's decisions, shall have a documented calibration status.

C 700 Document requirements

701 The Client (or the builder or manufacturer) shall make available to DNV the documentation accordingto documentation lists supplied by DNV upon receipt of certification request, before production commences(see Section 3 for generic information requirements).



702 Document requirements covers:

— Documentation required for approval. Moreover, DNV may specify alternative or additional requirements. — Corresponding technical descriptions, calculations and data, including material specifications.

C 800 Survey801 Surveillance scope and extent will be based on the criticality of the systems and components identifiedduring the design appraisal/Qualification stage. Where surveillance by DNV is required for a unit orinstallation, the following will normally be verified:

— that the construction and dimensions comply with relevant standards and the approved documentation— that the required materials are used— that the materials, components and systems have been certified in accordance with relevant standards and

qualification basis— that the work is carried out in compliance with relevant standards and with good engineering practices— that satisfactory tests are carried out to the extent and in the manner prescribed by relevant standards.

802 Supervision will be carried out at the building yard and/or the sub-suppliers at the discretion of DNV,which also decides the extent and method of control.803 The verification method applied by DNV at the building yard or at the manufacturer will be based on acombination of audits of an accepted quality system and visual inspections and tests.

C 900 Functional testing901 Functional tests will be carried out as deemed necessary by DNV. 902 A test programme shall be prepared by the Client/builder. The programme shall specify systems andcomponents to be tested, and the testing procedure. The programme shall include sea tests of the complete unitwith machinery and equipment installed (as applicable). The tests shall give evidence of satisfactory operationin accordance with the design basis. When testing the control and safety system, failure modes shall besimulated as realistically as possible.

Guidance note:Tests, in general, are normally made for calibrating analysis tools or obtain data to deal with uncertainties and shouldbe used where and with the scale defined in the Qualification Process and in line with the stage of development.


903 Data shall be recorded according to the test programs as considered necessary by DNV. All systems areexpected to be inspected and tested by the builder prior to being presented for final testing.904 Final testing after installation of the converter on location may also be carried out. The extent and scopeof DNV involvement will be identified during the design appraisal and Qualification stage.

C 1000 Final Certification DocumentationAfter examination of the surveyor's report and confirmation that the requirements have been met, a certificatewill be issued. 1001 Provided the requirements for maintenance of certificate are complied with, and unless the certificatehas been withdrawn in writing at an earlier stage, the certificate will be valid for 5 years. 1002 An “Appendix to the certificate” will be issued stating assumptions for the assignment of certificationand conditions regarding the use of the unit or installation, which were established or assumed at the time ofassignment.

C 1100 Maintenance of Certificate – In-service Requirements1101 In order to maintain the certificate the tidal or wave energy converter will need to undergo regularsurvey. Typically this will involve an annual survey and a more comprehensive 5 yearly survey. The extent ofthe survey (areas, methods, frequencies) will normally be dictated by the design life, degradation mechanismsand the consequences of possible failure. Additional surveys and design assessment may need to be carried outshould the converter or one of a similar design sustain damage, or if it significantly modified (changes in theloading and structural response, power output, safety and control systems and changes other than replacements,see also C1204) in the periods between regular surveys.

Guidance note:The annual survey will normally be general visual inspection of structures and main components in easy accessibleareas. Every five years the survey will be a combination of general and close visual inspection. The determination ofnumber of details for close visual inspection will be based on the fatigue utilisation, service life of components andrisk considerations. Recommendations for non destructive examination (NDE) may also be given by DNV. The in-service inspection scope should be established at the completion of the design phase prior to installation. At the survey other aspects covered within the certification will also be reviewed. This may include results from themonitoring system, review of measurements of loading and structural response, records of incidents and maintenance



carried out as well as agreements between actual and expected power take-off. Depending on the criticality ofcomponents of the power take-off system, the DNV surveyor should also attend the maintenance for visual inspectionand condition assessment of the components.


1102 The survey timing and methods will take account, as far as possible, of the inspection and maintenanceprograms adopted by the Operator.1103 Planning for the operations phase and the need for inspection and maintenance shall be part of theOperators design and construction philosophy. The extent and type of survey shall be discussed with DNV aspart of this process.

C 1200 Other conditions1201 Appropriate actions according to the certified ISO 9001:2000 system (or its principles) with respect tocomplaints and any deficiencies that affect compliance with the requirements for the Type Certificate shall bein place. Records should be kept of all complaints relating to the compliance for the device with the standardsand requirements used for the certification. These records as well as documentation for actions taken shall beavailable to DNV and to the certification body which have certified the ISO 9001:2000 system (if applicable).Reporting of these records as well as minor modifications shall be submitted to DNV.1202 Any safety related accident/failure of the installed certified devices shall be reported immediately toDNV together with proposed corrective actions. Such major accidents/failures may result in request forcorrective actions to be taken in order to maintain the Type Certificate. 1203 Major modifications to the design, procedures, specifications etc. must be reported without delaytogether with all documentation affected by the modification for the Type Certificate to be maintained/extended.1204 Modifications to a device for which a Type Certificate has been issued are permitted only if they do notchange or affect the principle characteristics at all. As an example, modifications to the principle characteristicsof Type Certificates are defined as follows:

— a change in size or any other modification resulting in loading response increase by more than 2% abovethe uncertainty calculated/measured and included in the Type Certificate

— a different design of safety/control system— a different way of limiting the power input— change of main components for other not equivalent as per the qualification process— increase of the power output by more than 5% above the uncertainty calculated/measured and included in

the Type Certificate.

1205 If modifications outside the limitations have been carried out this means that a different type of devicehas been produced, and a separate Type Certificate for this type should be applied for.1206 Upon failure to conform to the conditions of the Type Certificate, the Certificate Holder is requested tocorrect the non-conforming situation within a specified time frame.1207 If no satisfactory corrective action is taken, the Type Certificate in question will be withdrawn and theaccreditation authority, under whose authority the Type Certificate was issued, will be informed accordingly.Certification documents issued by DNV shall upon withdrawal or suspension be returned as requested by DNV.

D. Verification of Procured Items

D 100 General101 The scope of certification includes certification of materials, components and systems (CMC) intendedfor the device. The standards define the extent of the certification of the procured items that is needed forcertification of the energy converter device based on the results of the initial stages of qualification (technologyassessment, failure mode identification and risk ranking). The objective of the certification is to ensure thatmaterials, components and systems used in the device to be certified by DNV conform to the referencedstandards within the framework of the certification.102 The aspects discussed here are based on the Technology Class 1, or in some cases Technology Class 2.103 The certification is a conformity assessment normally including both design and production assessment.The production assessment includes inspection and testing during production and/or of the final product. Thedesign assessment of the materials, components and systems shall either be on a “case by case” basis or followthe procedure for type approval.

D 200 Case-by case approval201 When the “case by case” procedure is used, documentation of the design shall be submitted forassessment for every application as required in the rules. A design assessment letter or design verification



report shall be issued by DNV when compliance with the requirements for the design for the actual applicationis confirmed. The designer must ensure that their design accounts for all relevant design loads, includingaccidental loads derived from any risk assessment carried out by the project.

202 The production assessment of materials, components and systems shall either be on a “case by case”basis or on the basis of an agreed Manufacturing Survey Arrangement (MSA).

203 When the “case by case” procedure is used, the survey and testing shall be performed on the basis ofapproved design documentation for the actual application and as required in the standards. Compliance withthe approved design documentation and the requirements shall be documented through certificates as requiredin the standards.

204 When the production assessment is based on an MSA, the survey and testing shall be performed on thebasis of approved design documentation and in accordance with requirements and procedures laid down in theMSA. Compliance with the approved design documentation and the requirements shall be documented throughcertificates as specified in the MSA or as required in the standards.

D 300 Type approval

301 Type approval is a procedure for design assessment. Type approval can be applied to a:

— product — group of products — system.

This procedure should normally be used for design assessment of standard designs.

302 When the type approval procedure is used, documentation of the design and the results of type testing asrequired in type approval programmes and the standards, shall be submitted for assessment. A type approvalcertificate shall be issued by DNV when compliance with the requirements for the design is confirmed. Thetype approval certificate has a validity of 2 or 4 years depending on type of material, component and system.

303 The type approval procedure will normally consist of the following elements:

— design approval — type testing — issuance of type approval certificate.

The type approval procedure used by DNV is described in DNV Standard for Certification 1.2.

304 For certain products, equipment and systems as defined in the standards, type approval is sufficient asthe assessment needed for conforming product quality, i.e. production assessment is not required.

305 For certain products, equipment and systems as defined in the standards, type approval is a mandatoryprocedure for design assessment.

306 For products, equipment and systems manufactured for stock, type approval shall be the normalprocedure for assessment of design.

307 For type approved products, where the basis for approval is the standards, documentation of the productneed not be submitted for approval for each device unless otherwise stated as a condition on the type approvalcertificate. In such cases only the arrangement or system plans, interface plans and those plans mentioned onthe type approval certificate shall be submitted for approval.

D 400 Documentation of Certification

401 Certification of materials, components and systems shall be documented by the following types ofdocuments:

1) DNV Product certificate (NV):A document signed by a DNV surveyor stating:

— conformity with standard requirements — that tests are carried out on the certified product itself — that tests are made on samples taken from the certified product itself — that tests are performed in presence of the surveyor or in accordance with special agreements.

2) Works certificate (W):A document signed by the manufacturer stating:

— conformity with standard requirements — that tests are carried out on the certified product itself — that tests are made on samples taken from the certified product itself — that tests are witnessed and signed by a qualified department of the manufacturers.



3) Test report (TR):A document signed by the manufacturer stating:

— conformity with standard requirements — that tests are carried out on samples from the current production.

The applicable standards will specify which of the above mentioned documentation will be required.402 Where the standards require Works certificate (W) or Test report (TR), the surveyor may at any timerequire tests to be carried out in his presence and/or check elements of the quality control in operation.403 For identification and traceability, certified products shall be stamped in accordance with the markinggiven in the product certificate and as specified by the applicable standards.404 For certain components and systems as defined in the standards, the certification may be based ondefined internationally recognised standards and certification schemes that cover the overall quality, safety andenvironmental standard of the rules. Compliance with the requirements of the standard shall be documented asrequired by the standard.

D 500 Manufacturing survey arrangement501 When the procedures and processes of a building yard's or a manufacturer's quality system meet thequality, safety and environmental standard of the standards, a manufacturing survey arrangement (MSA) maybe established with the yard or the manufacturer as an alternative to the verification and production assessmentdescribed in the applicable standards.502 The agreed MSA shall be described in a document stating the requirements, scope, acceptance criteria,documentation and the roles of DNV and the yard or the manufacturer in connection with the productionassessment.503 When it is agreed through an MSA that the majority of the required surveys and tests are being completedwithout the presence of a surveyor, it is conditional upon the manufacturer having in operation a quality systemcertified by an accredited certification body to ISO 9002, or equivalent.504 When establishing an MSA, an initial assessment of the manufacturer's ability to control product qualityand to comply with the scope, requirements and criteria laid down in the MSA shall be performed. The extentand frequency of periodical assessments of the manufacturer shall be included in the MSA.505 An MSA is normally given a validity of 4 years. When the MSA is based on a certified quality system,the MSA automatically becomes invalid if the quality system certification is no longer valid.



SECTION 3DOCUMENTATION

A. General

A 100 Typical documentation and type of service

101 In this chapter typical documentation to be submitted in connection with certification of a tidal or waveenergy converter is described. The level of detail and areas to be covered will obviously depend on thecontractual agreements. It should be noted that for certification of a tidal or wave energy converter there willbe a minimum set of areas to be documented in order for DNV to issue a certificate. The areas described in thischapter are covering more than the minimum requirements in this respect.

102 Depending on type of device, parts of or whole groups of documentation described in the following willnot be relevant. A detailed list reflecting the type of converter and operational mode must therefore beestablished in each case.

B. Structural design

B 100 Type of installation

101 Tidal and wave energy converters may be either fixed or floating, and the construction material may besteel, concrete or composite or a combination. The documentation requirements will vary depending onconstruction material and type of device.

B 200 Environmental data

201 The environmental data used as basis for the design should be submitted. This should include:

— waves— wind— current profile and turbulence— water depths— tide— soil conditions— marine growth, thickness and specific weight— seismic conditions— design temperature.

B 300 Floating Tidal and Wave Energy Converters

301 Typical documentation to be submitted for verification of the structural design of a floating tidal or waveenergy converter will be:

— general arrangement plan— plans for spaces and tanks— structural design brief— design load plan, including design accidental loads— structural categorisation plan— structural drawings— model test documentation— loading manual— docking arrangement plan— fabrication specification, including welding procedures— design analyses, both global and local design, including temporary phases such as transit— standard details— local arrangement plans— corrosion protection— opening and closing appliances— stability, including inclining test procedure, stability manual watertight integrity plans, etc.— freeboard plan and list of watertight and weather tight items— description of access for inspection and maintenance of the structure.



B 400 Fixed Tidal and Wave energy converters

401 Typical documentation to be submitted for verification of the structural design of a fixed converter willbe:

— general description of the design in terms of size and type of structure, layout of equipment, deckelevations, operational loading requirements and design life and construction material

— general arrangement plan— description of computer programs used in design— field data in terms of location and orientation of the converter— soil data and foundation analysis— description of scour protection system— structural design brief— design load plan, including design accidental loads— structural categorisation plan— structural drawings— fabrication specification, including welding procedures— design analyses, both global and local design, including temporary phases such as transit— standard details— local arrangement plans— corrosion protection— description of access for inspection and maintenance of the structure.

Foundation and mooring design must be shown by analysis (and testing if necessary) to be sufficient to survivethe site conditions and lifetime identified in the basis for certification. This will be confirmed by independentverification by DNV. Internationally recognised standards should be used where relevant.

C. Position keeping

C 100 General

101 The position keeping system can be included in the verification of a tidal and wave energy converter.Typically it will comprise the anchors/suction piles, anchoring lines, windlasses and winches on board theconverter. The following documentation will typically be submitted:

— line and anchor pattern— type and weight and dimension of all line segments— characteristic line strength— anchor type, size, weight and material specification— arrangement of fairleads and anchor points/pretensions— position and weight of buoyancy elements and weight elements— position and type of connection elements, such as Kenter shackles, D-shackles, and triplates— windlass, winch and stopper design— mooring line tensions in ULS and ALS limit states— fatigue calculations of mooring line segments and accessories— strength calculations of anchors, windlass components and fairleads— corrosion allowance.

D. Machinery and Marine Systems

D 100 Floating Installations

101 Machinery and marine systems are covered by DNV-OS-D101, Marine and Machinery Systems andEquipment. Typical systems are ballast system, bilge system, fuel system, HVAC system, etc. Documentationfor such systems should include:

— functional descriptions— gear and other equipment used for production of electricity— piping (or ducting) and instrumentation diagrams— piping specifications— control system— reliability studies for critical systems.



E. Electrical systems

E 100 General101 Electrical systems are covered by DNV-OS-D201, Electrical Installations. The verification of theelectrical system on a tidal and wave energy converter will be based on the following typical documentation:

— system description— line diagram— generator description— converter description— overall single line diagram for emergency power— principal cable routing sketch — cable selection philosophy— load balance— discrimination analysis — table of Ex-installation — electrical system calculations — battery systems.— reliability studies for critical systems.

F. Instrumentation and control systems

F 100 General101 Typical documentation for instrumentation and control systems is:

— functional description of control systems— system block diagrams— power supply arrangements— user interfaces— instrumentation and equipment lists— arrangement and layouts— description of functions covered by software— reliability studies for critical systems.

G. Fire protection and safety systems

G 100 General101 As a general basis for the fire protection and safety systems, a risk analysis should be conducted, wheredesign accidental loads are defined, as well as risk mitigating measures. These loads should cover fire andexplosion loads, impact loads from dropped objects and collisions, unintended flooding and loads caused byextreme weather. Based on input from the risk analysis and prescriptive requirements in applicable codes, thefollowing should typically be documented:

— active and passive fire fighting systems— general arrangement— emergency shutdown system— escape routes— evacuation systems and life saving appliances.
