DNVGL-SE-0420 Edition December 2015

Transcription

1 SERVICE SPECIFICATION DNVGL-SE-0420 Edition December 2015 Certification of meteorological masts The electronic pdf version of this document found through is the officially binding version. The documents are available free of charge in PDF format.

2 FOREWORD DNV GL service specifications contain procedural requirements for obtaining and retaining certificates and other conformity statements to the objects, personnel, organisations and/or operations in question. December 2015 Any comments may be sent by to This service document has been prepared based on available knowledge, technology and/or information at the time of issuance of this document. The use of this document by others than DNV GL is at the user's sole risk. DNV GL does not accept any liability or responsibility for loss or damages resulting from any use of this document.

3 CHANGES CURRENT General This is a new document. Changes current Service specification, DNVGL-SE-0420 Edition December 2015 Page 3

4 Contents CHANGES CURRENT... 3 Sec.1 Introduction General Objective Scope Application Definitions Terminology and definitions Abbreviations and symbols References Procedural requirements Customer - DNV GL interaction Certification requirements, quality management Documentation requirements Standards, codes and additional requirements Combination of standards Surveillance requirements...14 Sec.2 Service Overview Procedure and content of project certification Overview Project certification phases Deliverables Certificate validity and maintenance...16 Sec.3 Service Description Phase I: Design basis General Design basis met mast structure Equipment and instrumentation Phase II: Design General Met mast structure Equipment and instrumentation Phase III: Manufacturing Met mast structure Equipment and instrumentation Phase IV: Transport and installation General Met mast structure transportation and installation surveillance Equipment and instrumentation installation surveillance Phase V: Commissioning General Equipment and instrumentation Phase VI: In-service General Met mast structure Equipment and instrumentation...33 App. A Annex project certificate App. B Annex statement of compliance Contents Service specification, DNVGL-SE-0420 Edition December 2015 Page 4

5 SECTION 1 INTRODUCTION 1.1 General This service specification (SE) specifies DNV GL s services for certification of meteorological (met) masts. DNVGL-SE-0420 serves as a: guidance for developers/owners from concept to in-service of the met mast guidance for different subcontractors such as designers and manufacturers description to meet the state-of-the-art requirements for met masts common communication platform for describing the scope and extent of activities performed for certification of a met mast (met mast structure/equipment and instrumentation/both) contractual basis for certification of a met mast. The service specification is divided into the following main sections: Sec.1 provides general information of the met mast covered in this service specification and general requirements regarding certification. Sec.2 provides a service overview for the defined project phases and the deliverables of project certification as shown in Table 1-1. Sec.3 describes the services in detail, where the verification activities associated with the various project phases and their certification are presented in more detail. The following table provides an application oriented guidance to determine which section applies for the part of interest. Table 1-1 Certification of met masts document guidance references Phases Met Parts mast Met mast structure Equipment and instrumentation I design basis [3.1] [3.1.2] [3.1.3] II design [3.2] [3.2.2] [3.2.3] III manufacturing [3.3] [3.3.1] [3.3.2] IV transport and installation [3.4] [3.4.2] [3.4.3] V commissioning [3.5] [3.5.1] [3.5.2] project certificate project certificate met mast structure equipment and instrumentation project certificate met mast VI in-service [3.6] [3.6.2] [3.6.3] The DNV GL document scheme is organized according to a three-level document hierarchy, with these main features: Principles and procedures related to DNV GL s certification and verification services are separated from technical requirements and are presented in DNV GL service specifications (SE). Service specifications present the scope and extent of DNV GL s services Technical requirements are issued as self-contained DNV GL standards (ST). Standards are issued as neutral technical standards to enable their use by national authorities, as international codes and as company or project specifications without reference to DNV GL s services Associated product documents are issued as DNV GL recommended practices (RP). Recommended practices provide DNV GL s interpretation of safe engineering practice for general use by industry. Guidance note: The latest revision of all DNV GL documents may be found in the list of publications on the DNV GL website ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Service specification, DNVGL-SE-0420 Edition December 2015 Page 5

6 1.2 Objective Certification of the met mast ensures that the met mast can be operated safely and cost efficiently, that risks are mitigated and that all technical, design and construction requirements are met. The DNV GL scheme described in this service specification is to detail and clarify the verification activities and facilitate achieving compliance with the state-of-the-art. The service specification has been written with the aim to provide a flexible certification concept to address individual needs, ro reduce costs over the life-time and at the same time to not compromise the added value and quality. Additional phases can be chosen to enhance the met mast functionality, reliability and value. Mandatory and optional certification phases in the DNV GL scheme are outlined in Figure 1-1. I Design Basis Statement of Compliance DNV GL project certificate for Mandatory phases II Design Statement of Compliance III Manufacturing Statement of Compliance IV Installation Statement of Compliance V Commisioning Statement of Compliance maintenance of certificate Optional phase for VI In-Service Statement of Compliance Figure 1-1 Phases in DNV GL project certification The main advantage of using the DNV GL scheme are: more guidance and descriptions to facilitate the application all met mast relevant topics are addressed in one service specification flexible concept to address and allow project specific needs shorter update cycles of standards and recommended practices to meet the latest state-of-the-art. Depending on the specific individual interests and agreed scope the benefits by applying this service specification can be among others: independent approval of the met mast to reduce the risk in developing and designing building of trust in design and construction confidence in technical integrity reducing costs by early detection of non-conformities confirmation of requirements as stated by project developers, investors, operators, manufacturers, governmental and non-governmental organisations Service specification, DNVGL-SE-0420 Edition December 2015 Page 6

7 Proof by an independent body to meet the international acknowledged state-of-the-art utilise certificates for authorisation by governmental institutions proof to an investor or insurer that third party approval has been performed succesfully secure better insurance rates minimis financial project risks mitigate risks to environment and people avoid damages ensure reliable measurements. 1.3 Scope The certification concept for met masts constitutes a robust means to provide, through independent verification, evidence to stakeholders (financiers, partners, utility companies, insurance companies, the public, governmental and non-governmental organisations) that a set of requirements laid down in standards are being met during design and construction, and maintained during operation of a met mast. The service specification describes also how to maintain the project certificate by periodic maintenance during the service life of the met mast. 1.4 Application This service specification applies to met mast certification and related verification tasks during the design, construction, transportation, installation, commissioning and operation of met masts. The following parts of met masts (see Figure 1-2) are covered by the services described herein: met mast structure equipment and instrumentation (E&I). Met mast structure Equipment and instrumentation (E&I) Figure 1-2 Definition of met mast parts (structure, E&I) Service specification, DNVGL-SE-0420 Edition December 2015 Page 7

8 Each part of the met mast may be further subdivided into components for met mast structures and equipment and instrumentation sections. In this service specification, the terms met mast structure and equipment and instrumentation (E&I) are used for the following: Components of a met mast structure are: onshore - foundation - tower offshore - foundation - sub-structure including transition piece, work platform, boat landing and associated secondary steelwork (e.g. railings, davit crane, gates, grillage etc.) - tower Components of Equipment and Instrumentation are: onshore - meteorological instrumentation - data acquisition system (DAS) - electrical power supply (EPS) - communication system (Com) - aviation lights - instrumentation attachments: Parts supporting the equipment and instrumentation (e.g. booms, junction boxes and all associated attachments to the structures) - all cables associated with the above offshore - meteorological instrumentation - oceanographic instrumentation - data acquisition system (DAS) - electrical power supply (EPS) - communication system (Com) - aviation lights - aids to navigation (AtoN) - instrumentation attachments: Parts supporting the equipment and instrumentation (e.g. booms, junction boxes, protective shelters and all associated attachments to the structures) - all cables associated with the above. Service specification, DNVGL-SE-0420 Edition December 2015 Page 8

9 Figure 1-3 Definition of offshore and onshore met mast structural components This service specification is generally applicable for fixed met mast. However, these specifications are broadly applicable to the case of floating installations. In this case it is recommended to agree the scope of work for certification with DNV GL at an early stage. 1.5 Definitions Terminology and definitions Table 1-2 Definitions of verbal forms Verbal forms shall should may Definition verbal form used to indicate requirements strictly to be followed in order to conform to the document verbal form used to indicate 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 necessarily required verbal form used to indicate a course of action permissible within the limits of the document Service specification, DNVGL-SE-0420 Edition December 2015 Page 9

10 Table 1-3 Definitions of terms Term asset certification component customer design brief foundation instrumentation attachments optional services outstanding issue part primary structure project certificate recommendation secondary structure special structure sub-structure support structure tower verification Definition term used in the context of met mast projects to describe the project or object to be developed, manufactured and maintained In this service specification the term refers to the whole met mast system comprising met mast structure and Equipment and Instrumentation. refers to third-party issue of a statement, based on a decision following review, that fulfilment of specified requirements has been demonstrated related to products, processes or systems (ISO 17000) a main sub-part of an asset In this service specification, the term refers to the tower and support structure of the met mast structure and elements of the E&I. DNV GL s contractual partner (applicant) supporting document for describing methodologies for design calculations Mostly issued by the designers. the part of the support structure for a meteorological mast that transfers the loads acting on the structure into the soil parts supporting the equipment and instrumentation (e.g. booms and uprights, junction boxes, protective shelters and all associated attachments to the structures) optional services are services which are not part of the scope which is required in order to obtain statement of compliance and project certificates. the term outstanding issue is used to denote a deviation from standards and technical requirements specified in the certification agreement, and which needs to be completed for full compliance parts of the met mast are referring to either met mast structure or equipment and instrumentation the primary structure consists of the load-bearing structure that transfers permanent loads, life loads and environmental loads, caused by gravity and environment and actions on the support structure, to the soil Structural parts the failure of which will have substantial consequences shall be classified as primary structure. a document signed by DNV GL and affirming that, at the time of assessment, the part referred to in the certificate met the requirements stated in the normative documents non-mandatory advice secondary structures are e.g. boat landings, access ladders, access platforms same as primary structure In addition these parts are subject to particularly arduous conditions (e.g. stress condition that may increase the probability of brittle fracture, multi-axial stresses). term referring to the part of the support structure for a met mast which extends upwards from the soil and connects the foundation and the tower the support structure of a met mast is defined as the structure below of the tower structure and includes sub-structure and foundation of a met mast the tower is the structure that holds the wind measurement equipment, the height of the tower corresponds usually to the hub height of a wind turbine refers to the confirmation, through the provision of objective evidence, that specified requirements have been fulfilled (ISO 9000) Service specification, DNVGL-SE-0420 Edition December 2015 Page 10

11 1.5.2 Abbreviations and symbols Abbreviations and symbols used in this service specification. Table 1-4 Abbreviations Abbreviation ALS AtoN Com DAS E&I EPS EPC FEM FAT FLS IEC ISO MEASNET met O&M RP SE SLS ST ULS In full accidental limit state aids to navigation communication system data acquisition system equipment and instrumentation electrical power supply engineering, procurement and construction finite element method factory acceptance test fatigue limit state international electrotechnical commission international organization for standardization international network for harmonised and recognised measurements in wind energy meteorological operation and maintenance DNV GL recommended practices DNV GL service specification serviceability limit state DNV GL standards ultimate limit state 1.6 References This document makes reference to relevant international documents and DNV GL documents. Unless otherwise specified in the certification agreement or in this service specification, the latest valid revision of each referenced document applies. Table 1-5 DNV GL documents Reference Title DNVGL-ST-0126 Support structures for wind turbines (planned published 2016) DNVGL-ST-0437 Loads and site conditions wind for turbines (planned published 2016) DNVGL-RP-0416 Corrosion protection of offshore wind turbines (planned published 2016) DNVGL-RP-0005 Fatigue design of offshore steel structures Table 1-6 IEC documents Reference IEC Title Wind Turbines Part 12-1: Power performance measurements of electricity producing wind turbines Table 1-7 ISO documents Reference ISO 9000 ISO 9001 ISO/IEC ISO/IEC Title Quality management systems Fundamentals and vocabulary Quality management systems Requirements Conformity assessment Vocabulary and general principles General requirements for the competence of calibration and testing laboratories Service specification, DNVGL-SE-0420 Edition December 2015 Page 11

12 Table 1-8 Other documents Reference EN EN EN EN Title Eurocode 7: Geotechnical design Part 2: Ground investigation and testing Eurocode 3: Design of steel structures Part 3-1: Towers and masts Eurocode 3: Design of steel structures Part 1-9: Fatigue Wind Turbines Protective measures Requirements for design, operation and maintenance 1.7 Procedural requirements Customer - DNV GL interaction DNV GL provides third party verification and conformance testing of wind farm service projects, especially related to specific customer needs. This document has a dual objective. It serves as a publicly available description of DNV GL s certification services for met masts and it should be referred to as a contractual document in the certification agreement between the customer and DNV GL. The document specifies the obligations of the customer when his met mast shall be certified, as well as DNV GL s service obligations to the customer. The deliverables by DNV GL shall be agreed in detail between the customer and DNV GL as part of the contract. In general the DNV GL project certificate is issued when all of the required statements of compliance according to the project certification scheme have been issued and the final evaluation has been performed successfully. The deliverables are listed in [2.1.3]. Each certification phase for a component may be verified independently according to the DNV GL project certification scheme and shall be completed upon successful evaluation with the issue of a statement of compliance for the part under verification. Final timeframes of the verification and certification activities shall be discussed and agreed between the customer, DNV GL, and suppliers before commencement of the work. The typical project certification applicant is the wind farm developer, owner or operator, although this could equally be an EPC contractor, responsible for supply and installation of a certified met mast structure. The splitting of the project certificate per part allows the involvement of part related contractors in the project set-up. This allows the involvement of additional resources from an applicant perspective Certification requirements, quality management In general subsequent phases shall not be initiated before previous or dependent phases are completed and approved. For example, prior to verification of the manufacturing phase, the design basis phase and the Design phase shall both be completed and approved. Therefore the manufacturing of the components for the project shall not be started before the design is approved and surveillance is agreed. Alternative ways and the related risks shall be discussed and agreed with DNV GL in advance. The customer shall provide evidence of a consistent quality management system covering all aspects of the development and operation of the met mast. In particular the customer shall show quality relevant procedures to DNV GL for his procedures and his suppliers, covering design, manufacturing, transportation, installation, inspection, operation and documentation processes. When a valid certificate for ISO 9001 of an accredited certification body is in place, the certification body may reduce this assessment to a plausibility check. In general test reports delivered shall be prepared by accredited testing laboratories and meet the requirements of ISO IEC and relevant standards. For non-accredited test laboratories, DNV GL shall verify that the testing laboratories carry out their work according IEC/ISO 17025, as applicable Documentation requirements The documentation submitted for the certification process shall be complete and self-explanatory. The content shall meet the requirements of the applied standards. All relevant documentation shall be subject oriented and in a logical sequence to facilitate cross checking between documents (e.g. design basis, design, manufacturing, transport, installation, commissioning etc.). Each document shall be named explicitly by Service specification, DNVGL-SE-0420 Edition December 2015 Page 12

13 e.g. title, report no., page no., date and a revision description table. Furthermore the documents should be signed officially at least by the author and/or the approver to identify responsibilities. Alternatively the documentation submitted shall bear unambiguous evidence of having been subject to designer s and/or owner s own quality management system. The documentation, including standards and codes as well as other requirements and specifications, shall be prepared in the English language, unless otherwise agreed in writing between DNV GL and the customer. All documentation for the verification shall be forwarded to DNV GL in electronic form, preferably as pdffiles. Other forms of documentation such as print-outs can be an alternative, if agreed. Guidance note: The documents submitted should be on a logical work package basis per phase, see [2.1.2], and cover the requirements as stipulated in Sec.3 to facilitate the process. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e Standards, codes and additional requirements The standards, codes and requirements which form the basis for the met mast project shall be listed and agreed in the so-called design basis document at a very early stage. For the site in question, relevant statutory requirements shall also be listed. Such requirements could be de-commissioning and safety related issues such as requirements for embarkation and rescue. Other requirements relevant for the certification such as specific requirements of the owner shall be listed as well. The standards, codes and additional requirements, which are applicable for the project and site in question, will be verified for compliance with the design prerequisites of the project and for completeness and adequate suitability and applicability. The verification of the choice of standards, codes and requirements shall be conducted early in the project phase in order to avoid fundamental discussions on this basic aspect of the design basis. For dated standards and codes, only the edition cited applies. For undated references, the latest edition of the referenced document including any amendments applies. In case of deviations from this rule, it shall be agreed on an individual basis and in advance with DNV GL Combination of standards DNV GL certification, according to internationally recognized standards, shall follow the principles described in this service specification. Wherever combinations of such standards and external criteria are used, the exact terms of reference and documents to be issued shall be agreed at the beginning of the project and shall be specified in detail in the design basis. The application of standards other than those referenced here does not allow for a reduction of the targeted safety as described in this service specification in combination with the related technical standards. DNV GL reserves the right to ask for additional requirements to cover issues essential to the certification process and not covered by the standards in question. It is not allowed to combine safety measures of different standard systems due to the possible differences in the underlying safety philosophies of the different standard systems. In case standards are combined, caution shall be exercised and the choice of standards is subject to acceptance by DNV GL. Guidance note: Within a particular standard, aspects such as requirements for partial safety factors for calculations of design loads and design resistance are generally mutually balanced to give an overall acceptable safety level. In another standard with the same overall acceptable safety level, the requirements for the safety factors may have been balanced differently. Picking requirements for load factors from one standard and material factors from another may therefore easily result in unpredictable, and possibly too low or too high, safety levels. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Service specification, DNVGL-SE-0420 Edition December 2015 Page 13

14 1.7.6 Surveillance requirements The customer, or other entity having legal responsibility for the premises where DNV GL personnel will work, shall inform DNV GL of any safety and/or health hazards related to the work and/or any safety measures required for the work, prior to starting the work, or if such information is not available at that time, during the performance of the work. Whenever DNV GL undertakes to work on site, the customer shall provide all adequate safety measures to ensure a working environment that is safe and in accordance with all relevant legislation. If at any time during the execution of work on site a DNV GL employee judges that the work situation is unsafe then work shall be suspended until such situation has been made safe. For on- and offshore projects the transport and installation surveillance starts from loading at the manufacturers production sites and ends at the wind power plant site. Guidance note: In offshore projects the transport surveillance may be combined with the marine warranty surveillance, if both activities are carried out by DNV GL or other acknowledged marine warranty surveyor and agreed at the beginning of the project. Caution should be taken as the scope of the transport surveyor and marine warranty surveyor differ significantly with respect to the certification purpose. Briefings and written approvals for consent between the parties with respect to availability and instructions of the marine warranty surveyor for the success of the transport surveillance are required. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Service specification, DNVGL-SE-0420 Edition December 2015 Page 14

15 SECTION 2 SERVICE OVERVIEW 2.1 Procedure and content of project certification Overview Project certification of met masts in accordance with this service specification is carried out according to the DNV GL project certification scheme. The project certificate for the onshore or offshore met masts comprises the project specific certification of the two parts of the met mast ensuring the verification of the boundary condition between the two parts. A project certificate met mast consists of certification of the following parts with the respective statements of compliance and certification reports: met mast structure equipment and instrumentation. The DNV GL project certification scheme consists of six phases, see Figure 1-1. The phases refer to the project certification phases design basis, design, manufacturing, transport, installation, commissioning and maintenance of the certificate during the in-service phase. Statements of compliances will be issued after successful completion of each phase. Statement of compliances can be split up for each component and issued on request. Phases I V are mandatory for obtaining the project certificate. The project certificate for a met mast will be issued after successful completion of all phases for all parts of the met mast. In case of outstanding issues provisional statements of compliance and provisional project certificate may be issued on request, see [2.1.3]. The project certificate may be maintained throughout the in-service phase. For maintenance of the certificate throughout the in-service phase, reference is made to [2.1.4] Project certification phases The project certification phases are specified below: Phase I: Phase II: Phase III: Phase IV: Phase V: Phase VI: Design basis covers the site conditions and the basis for design. Design covers the steps necessary to achieve final design verification. This verification includes a site-specific design approval of the integrated structural system consisting of tower and support structure. And a design approval of E&I. Manufacturing covers the surveillance during manufacturing of the project related parts (met mast structure and E&I). Transport and installation covers the surveillance during transport and installation of the project related parts. Commissioning involves all follow-up verification and on-site inspections during the implementation of the met mast. In-service involves follow-up verification and periodic on-site inspections after start of operation and during the subsequent in-service period. Each phase will be completed with the issue of a statement of compliance. After completion of phases I through V for each part of the met mast and prior to the issue of the project certificate met mast, a final evaluation shall be performed. During the final evaluation DNV GL shall check all parts of the certification (certification reports and statements) for consistency and completeness with regard to the phases and parts described in this service specification. A DNV GL project certificate met mast will be issued after successful completion of the final evaluation. The certificate states compliance at the date of issue of the project certificate for a certain project with the standards specified and agreed in the design basis. The verification activities associated with the various certification phases and for the different met mast parts are presented in more detail in Sec.3. Service specification, DNVGL-SE-0420 Edition December 2015 Page 15

16 2.1.3 Deliverables A DNV GL project certificate may be issued for an onshore or offshore met mast or its individual met mast parts as defined in this service specification (see [2.1]). A project certificate for met mast contains the following: project certificate met mast structure project certificate equipment and instrumentation final certification report. Each project certificate is supported by at least the following: statement of compliance design basis statement of compliance design statement of compliance manufacturing statement of compliance transport and installation statement of compliance commissioning final certification report. For the maintenance of the project certificate a statement of compliance in-service shall be issued. Each statement of compliance is supported by a subject related certification report. The project certificate met mast can be obtained based on the two related project certificates or by fulfilling the mandatory phases for the two parts as described in this service specification. For surveillance during manufacturing, transportation, installation and commissioning as well as in-service, DNV GL shall report critical findings to the customer immediately after the surveillance. DNV GL shall issue surveillance reports to the customer and the frequency of these shall be agreed with the customer (for example daily, weekly or monthly). The reports shall describe the extent of the surveillance including findings, non-conformities and possible recommendations. The reports will be issued in electronic form and sent by to the customer. In the event that full compliance is not obtained during the project certification, the deliverables will depend on the nature of the lack of compliance. Three deliverable outcomes are available depending on the lack of compliance and are described in the following: No outstanding issue. Statements of compliance with the accompanying DNV GL certification reports will be issued. A DNV GL project certificate will be issued based on the statements of compliance for the met mast part verified. Non-safety critical outstanding issues. One or more provisional statement(s) of compliance will be issued with the outstanding issue(s) listed in the statement(s) of compliance. A provisional project certificate can be issued on request, which points out the outstanding issues. The outstanding issues listed on the statement(s) of compliance shall be repeated in the project certificate. Specific description of the outstanding issues will be given in the accompanying DNV GL certification reports. As outstanding issues become closed, an updated statement of compliance and finally a project certificate with no outstanding issues can be issued. Safety critical outstanding issues. (A) Statement(s) of compliance and the project certificate will not be issued. DNV GL shall deliver the DNV GL certification report(s) that would normally accompany the statement of compliance for the relevant phase. The DNV GL certification report(s) shall list the outstanding issues whose rectification is required before (a) statement(s) of compliance can be issued Certificate validity and maintenance The DNV GL project certificate refers to statements of compliance issued for the completed phases of the project certification. The validity of the project certificate is limited to the design life-time of the installation stated in the project certificate. Service specification, DNVGL-SE-0420 Edition December 2015 Page 16

17 Maintenance of the project certificate is conditional on periodic in-service verification by DNV GL and requires the following informations/actions: annual reporting by the customer covering the certified met mast project and including information about: met mast structure and E&I as installed at the site abnormal or deviant operating experience or operating failures as well as minor modifications. reporting by the customer of planned major modifications without delay and in sufficient time to allow for evaluation by DNV GL before implementation and to enable updating of the design phase and others, if relevant the met mast and the parts of the met mast of which it is comprised are maintained to a standard complying with the requirements of applicable codes and relevant manuals periodic inspections by DNV GL or other acknowledged in-service inspectors during the validity period of the certificate to check that the met mast corresponds with the certified design. The project certificate shall be confirmed one year after the date of first issuance by a statement of compliance in-service. When a periodic in-service agreement for the met mast is in place between DNV GL and the customer, the interval of confirmation of the project certificate is set to the duration of the service agreement plus one year; however, five years is the maximum period of confirmation. Following a successful completion of an in-service verification, a statement of compliance in-service that validates the project certificate will be issued. Re-certification may be necessary, if additional requirements for maintenance of the project certificate are set by national authorities or by the applicable design code or standard during the validity period of the certificate. Safety relevant incidents shall be reported to DNV GL without delay. DNV GL shall evaluate the incidents. In case of a serious defect of the met mast, DNV GL shall suspend the certificate until elimination of the cause. The certificate shall be reaffirmed after successful verification of the rectifying measure. Provisional statements or provisional certificates have a maximum validity of one year. During this period the customer shall document the closing of the outstanding issues and these shall be evaluated by DNV GL. Guidance note: In-service is optional according to this service specification. However, it becomes mandatory if the maintenance of the project certificate is chosen. It is strongly recommended to maintain the certificate from issuing date over the life-time. Resuming the certificate maintenance of a suspended or invalid project certificate may be difficult or even impossible. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Service specification, DNVGL-SE-0420 Edition December 2015 Page 17

18 SECTION 3 SERVICE DESCRIPTION 3.1 Phase I: Design basis General The purpose of the design basis verification is to evaluate if the site conditions and the basis for design, including general specifications, criteria, parameters, design approach and other assumptions relevant for design are properly established and documented and that this design basis is sufficient for a safe design of the met mast. DNV GL s verification activities are based on DNVGL-ST-0437 for loads, DNVGL-ST-0126 for structure and IEC for E&I. A design basis shall be provided to DNV GL that includes documentation of the following: a) site conditions b) standards, codes and requirements, see [1.7.4] c) design criteria d) procurement, fabrication, E&I testing, transport, installation and commissioning requirements e) operation and maintenance requirements. DNV GL shall verify the design basis for compliance with DNV GL s standards and other standards and codes identified in the design basis. Once the verification of the design basis has been successfully completed, DNV GL will issue a statement of compliance for Phase I: Design Basis for the verified met mast asset Design basis met mast structure Site conditions Integral part of the design basis are the site design conditions which denote all external influences acting on the met mast s primary and secondary structures and instrumentation attachments from outside. The following site design conditions shall be documented: wind conditions geotechnical conditions earthquake conditions other environmental conditions (e.g. ice, high temperatures, lightning). Additionally for offshore sites: marine conditions, and weather windows and weather downtime. Additionally for onshore sites: terrain and topographical conditions. The metocean conditions provided may be derived from site-specific measurements supported by hindcasts. Site-specific measurements shall when possible be correlated with data from a nearby location for which long term measurements exist. The monitoring period for the site-specific measurements shall be sufficient to obtain reliable data for design. As the purpose for the met mast is to collect wind (and wave) measurements site-specific measurements might not be available. Instead the wind and wave conditions can be based on data from nearby sites and hindcasts. The geotechnical site investigation and laboratory testing are assumed to have been carried out by companies with relevant experience of similar work. The quality of the soil investigation and the test results shall fulfil the requirements given in EN Service specification, DNVGL-SE-0420 Edition December 2015 Page 18

19 Not necessarily all parts of ISO/IEC may apply to the geotechnical field and laboratory work. In all cases, a description of all test procedures and relevant standards shall be presented. DNV GL shall verify that relevant reports properly document the site conditions. DNV GL shall assess the interpretation of the site conditions and the identification of the design parameters describing the site conditions to be used for design of the met mast. Design parameters representing the following conditions shall be included: wind climate ice geotechnical data other site conditions, such as seismicity, lightning, temperature. Additionally for offshore sites: wave climate correlation between relevant parameters such as wind, waves and current ocean current water level water depth seabed topography other site conditions, such as salinity, spray ice, marine growth, air density, traffic, disposed matters, pipelines and cables. Additionally for onshore sites terrain topography and complexity. The verification of the geotechnical design basis shall focus on: extent, quality and relevance of the soil investigations derivation of geotechnical design parameters from the soil investigations. The geotechnical design basis may, in addition to site-specific soil data, include derived soil profiles and recommendations regarding calculation methods Load and safety considerations The met mast (both for onshore and for offshore) shall be designed for the environmental load combinations given in DNVGL-ST Only the relevant load cases shall be taken into account, as not all load cases apply to a met mast. The met mast structure shall be designed to the same level of safety as the wind turbine support structure. The safety philosophy described in DNVGL-ST-0126 and DNVGL-ST-0437 is thus governing. This means that the safety factors and load factors given in DNVGL-ST-0126 and DNVGL-ST-0437 shall be applied Design criteria The design basis shall specify the principal input for the design process, in order to ensure that the final structure can be presumed to withstand the loads expected within the design lifetime. DNV GL will require and assess a description of the main design methodology, including the method of load calculation, and structural and geotechnical design methodologies. This is important in order to obtain early agreements regarding methodologies and to avoid discussions about overall principles and methods late in the project. Furthermore, the design basis has to identify all hazards that may jeopardize the safety or reliability of the structure, and translate them into specific dimensional or other design constraints which shall be fulfilled by the final design. A general description of the met mast and its characteristics shall be given. Service specification, DNVGL-SE-0420 Edition December 2015 Page 19

20 The design basis shall include a catalogue of requirements for the specific met mast planned. Those are in particular: external design parameters design load cases and load case combination for ULS, FLS, SLS and ALS if relevant load factors and load reduction factors partial safety factors applied on loads and materials description of simulations methods for extreme and fatigue design loads/response analysis target lifetime of coating and corrosion protection systems; interface between tower and sub-structure assumptions for coupled analysis consideration of ship impact, if relevant. If the design is partly based on model tests, DNV GL shall evaluate the test program. Damping shall be considered with the following parameters of contribution to damping: soil damping (due to internal friction) soil radiation damping (due to pressure wave radiation) wave damping viscous damping aerodynamic damping structural damping slosher dampers, tuned mass dampers etc Manufacturing, transport, installation and commissioning The design basis shall state assumptions, specifications and requirements for the structural design against loads occurring during manufacturing, load-out, transportation, installation and commissioning, such as environmental loads, lifting loads, and local loads from temporary supports. The design basis shall also state assumptions, specifications and requirements for the manufacturing, load-out, transportation, installation and commissioning programmes themselves. Commissioning requirements for the substructure and the foundation are usually very limited. The conditions prevailing at the installation site analysed and the rules and premises to be applied for the design shall be documented. This includes the following aspects: codes and standards specifications and tolerances limiting environmental conditions methods and loads of relevance for load-out, transport and installation requirements for load-out, transportation, installation and commissioning manuals quality management systems for the installation contractors description of the service vessel. The assumptions, specifications and requirements are expected to depend on owner s requirements as well as on the actual contractual arrangements for the met mast. DNV GL will verify assumptions, specification, manuals and requirements stated in the design basis Operation and maintenance The design basis shall state assumptions, specifications and requirements for the structural design against loads occurring during operation and maintenance. The design basis shall also state assumptions, specifications and requirements for the operation and maintenance programs. Assumptions, specifications and requirements may include: inspection scope and frequency Service specification, DNVGL-SE-0420 Edition December 2015 Page 20

21 target lifetime of components, systems and structures requirements for operation manuals requirements for service and maintenance manuals requirements for condition monitoring systems. DNV GL will verify assumptions, specification, manuals and requirements stated in the design basis Equipment and instrumentation The specifications and design basis concerning the instrumentation and related power supply systems, will be reviewed and assessed against the recommendations in IEC , Ed.1, as well as customer specifications, and typical industry practice. DNV GL shall issue a statement of compliance relating to the design basis of E&I Design criteria The design basis for the E&I systems shall be based on the specific site conditions, the consenting requirements and the particular measurements planned. The E&I criteria shall be verified with emphasis on the following points: definition of wind and other meteorological measurement requirements, including accuracy requirements definition of required height coverage for wind and other meteorological properties definition of required vertical sampling/resolution for wind and other meteorological properties identification of instrument mounting orientation(s) definition of oceanographic measurement requirements (if applicable) data quality as the paramount goal data availability data storage redundancy data transfer and communication aviation lighting and aids to navigation (AtoN) requirements Manufacturing, transport, installation and commissioning Design basis assumptions, specifications and requirements for manufacturing, factory acceptance testing, transportation, installation and commissioning may include, but are not necessarily limited to: supplier and manufacturer requirements and quality management systems E&I requirements for transportation, installation (incl. loading and unloading) and commissioning manuals limiting environmental conditions (e.g. limiting wind speeds for working at height) requirements and quality management systems for installation contractors. DNV GL shall verify assumptions, specification and requirements stated in the design basis Operation and maintenance The design basis shall state assumptions, specifications and requirements including, but not necessarily limited to: target lifetime of components, systems and structures O&M strategy for change out of sensors, periodic maintenance and unscheduled maintenance response for critical and non-critical systems. requirements for service and maintenance manuals requirements for condition monitoring signals or systems. DNV GL shall verify assumptions, specification and requirements stated in the design basis. Service specification, DNVGL-SE-0420 Edition December 2015 Page 21

22 3.2 Phase II: Design General DNV GL shall verify the final design for compliance with DNVGL-ST-0126 and IEC and other standards and codes identified in the design basis. Details of the verification activities in this phase are given in the following sub-sections Met mast structure General The verification of the design of the met mast structure shall be based on loads, capacities, design methods and principles specified in the approved design basis and in relevant DNV GL standards, e.g. DNVGL-ST For areas where the approved design basis or the DNV GL standards do not apply, reference to a recognized standard or design method may be accepted by DNV GL. The structural design verification shall include: loads and load combinations geotechnical design tower primary structure of the met mast secondary structure of the met mast transportation, installation, operation and maintenance grout design, if applicable connections. The following design reports and drawings shall be submitted to DNV GL for verification of the final structural and geotechnical design of the support structure: design documentation for the structural and geotechnical design calculations for ULS, SLS, FLS and ALS design calculation shall cover transportation and installation as well as operational conditions assumptions made for the calculations, for example regarding manufacturing and installation methods design report(s) containing design calculations for corrosion protection system(s) design report for the driveability study (if applicable) design drawings design documentation regarding scour and scour protection design Structural design loads The loads on the met mast structure may comprise the following loads: dead weight of structures and appurtenances dead weight and variable loads from equipment environmental loads from wind and ice accidental loads, for example dropped objects. Additionally for an offshore met mast: environmental loads from waves and ocean current impact loads on boat landings accidental loads from ship collisions. The principles used to establish load combinations for SLS, ULS, FLS and ALS shall be reviewed for compliance with DNVGL-ST The load combinations for the met mast structure shall be reviewed with a focus on: selection of load combinations Service specification, DNVGL-SE-0420 Edition December 2015 Page 22

23 selection of load factors and load reduction factors calculation results. For dynamically sensitive offshore met masts both the wind and waves contribute to the tower and substructure loading, if necessary, the customer has to determine the loading by a fully coupled analysis Geotechnical design Reference is given to DNVGL-ST-0126 for geotechnical design of foundations and guidance for prediction of scour and means to prevent scour. The purpose of a soil investigation is to provide a range of strength and deformation parameters with sufficient accuracy. Additionally the investigations shall supply information to evaluate deterioration from dynamic loads in sufficient detail. The investigations should be focused on the actual phase of the project with respect to extent, details and accuracy. The verification of the geotechnical design for the met mast shall focus on: evaluation of calculation methods, stability and failure modes review of geotechnical design calculations for ULS, SLS and ALS review of design documentation regarding soil preparation, tolerances and scour protection soil stiffness and soil capacity Primary structure The verification of the primary structural design of the met mast shall focus on: design methodology, safety level and materials review of design calculations for ULS, SLS, FLS and ALS Eigen frequency and vortex shedding analyses manufacturing and installation methods, with respect to the structural integrity of the(permanently) installed structure materials corrosion protection system(s) with respect to issues such as design life and maintenance as required in DNVGL-RP instrumentation attachment points (to tower) lightning protection design drawings and manufacturing specifications with respect to requirements in codes and standards as well as assumptions in calculations with respect to issues such as dimensions, materials, tolerances and testing. Fatigue design documents shall be based on DNVGL-ST-0126 or other recognised standards such as EN A combination of standards with regard to design fatigue factors and S/N-curves is not acceptable. The following verification activities are conducted: review of detailed design calculation reports, design drawings and manufacturing specifications for detailed structural design of the support structure relevant independent analyses of loads and structural strength. The verification may include independent analyses of the structure using appropriate methods, such as FEM analyses, and covers: structural strength (stress levels, buckling and joint check) fatigue life. The primary structure for the met mast tower will be analysed for wind loads, ice accretion if relevant, and interaction of wind measurement equipment and mast structure. The dynamic loading of the complete system of mast and foundation due to wave induced loads in the mast and foundation structure will be analysed. If the design includes highly utilized structural connections (e.g. grouted connections of steel structures and Service specification, DNVGL-SE-0420 Edition December 2015 Page 23