Dnvgl-ru-ou-0104: Self-elevating Units

Transcript

RULES FOR CLASSIFICATION Offshore units DNVGL-RU-OU-0104 Edition July 2015 Self-elevating units The content of this service document is the subject of intellectual property rights reserved by DNV GL AS (“DNV GL”). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL’s prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others. The electronic pdf version of this document found through http://www.dnvgl.com is the officially binding version. The documents are available free of charge in PDF format. DNV GL AS FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The procedural and technical requirements are used as a contractual document and includes both requirements and acceptance criteria. © DNV GL AS July 2015 Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision “DNV GL” shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL. General This document supersedes DNV-OSS-104, October 2014. Text affected by the main changes in this edition is highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour. On 12 September 2013, DNV and GL merged to form DNV GL Group. On 25 November 2013 Det Norske Veritas AS became the 100% shareholder of Germanischer Lloyd SE, the parent company of the GL Group, and on 27 November 2013 Det Norske Veritas AS, company registration number 945 748 931, changed its name to DNV GL AS. For further information, see www.dnvgl.com. Any reference in this document to “Det Norske Veritas AS”, “Det Norske Veritas”, “DNV”, “GL”, “Germanischer Lloyd SE”, “GL Group” or any other legal entity name or trading name presently owned by the DNV GL Group shall therefore also be considered a reference to “DNV GL AS”. Main changes July 2015, entering into force 1 January 2016 • General The revision of this document is part of the DNV GL merger, updating the previous DNV service specification into a DNV GL format including updated nomenclature and document reference numbering, e.g.: — Main class identification 1A1 becomes 1A. — DNV replaced by DNV GL. — DNV-RP-A201 to DNVGL-CG-0168. A complete listing with updated reference numbers can be found on DNV GL's homepage on internet. As a part of the formatting the original document structure consisting of Parts, Chapters, Sections etc. have been updated to Chapters, Sections and sub-sections etc. (with Pt.0 becoming Ch.1, Pt.1 becoming Ch.2 etc). To complete your understanding, observe that the entire DNV GL update process will be implemented sequentially. Hence, for some of the references, still the legacy DNV documents apply and are explicitly indicated as such, e.g.: Rules for Ships has become DNV Rules for Ships. • Ch.4 Sec.1 Structural design — [6.1.1]: Fixation system has been included in items described by the OS-C104 and C201. — [6.4]: 'Single' has been included in 3rd paragraph “In case of single failures”. • Ch.7 Sec.4 Commissioning process — [2.1.1]: Removal of thickness measurements requirements for intermediate surveys. • Ch.8 Sec.2 General provisions and requirements for surveys — [3.4]: Description of follow up inspections for units FUI>1 has been updated. • Ch.8 Sec.3 Preparation and planning — [2.4]: Corrections/ completions on IIP table and update of guidance note. • Ch.8 Sec.4 Periodical surveys — [1.2.1]: Requirement on quick closing valves has been updated to align with IACS UR Z15 2.8.2. — [1.2.10]: A new clause on loading instruments survey requirements has been added. — [3.2.2]: Description has been updated in line with general systematics. — [3.3.7]: Survey requirement for remote shutdown of fuel transfer system has been deleted. Editorial corrections In addition to the above stated main changes, editorial corrections may have been made. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 3 Changes – current CHANGES – CURRENT CH. 1 INTRODUCTION ....................................................... 11 Sec.1 General ....................................................................................................... 11 Sec.2 Objective..................................................................................................... 11 Sec.3 Scope .......................................................................................................... 11 Sec.4 Structure ..................................................................................................... 11 Sec.5 Definitions................................................................................................... 12 1 Verbal forms ...........................................................................................12 2 Definitions ..............................................................................................12 3 Abbreviations .........................................................................................15 CH. 2 GENERAL REGULATIONS AND CONDITIONS ............. 16 Sec.1 Sec.2 Sec.3 Classification principles............................................................................... 16 1 General ...................................................................................................16 2 Application .............................................................................................16 2.1 Interpretations ................................................................................. 16 3 Class scope and notations.......................................................................16 3.1 Scope ............................................................................................. 16 3.2 Notations......................................................................................... 17 Procedures .................................................................................................. 18 1 Plan 1.1 1.2 1.3 approval..........................................................................................18 Format ............................................................................................ 18 Subcontractors ................................................................................. 18 Plans and data to be submitted .......................................................... 18 2 Certification ............................................................................................18 3 Testing and surveys................................................................................18 Principles and conditions ............................................................................ 19 1 General ...................................................................................................19 2 Design principles ....................................................................................19 2.1 Scope ............................................................................................. 19 2.2 Safety and important systems ............................................................ 19 2.3 Redundancy..................................................................................... 20 2.4 Failure effects .................................................................................. 20 3 Environmental conditions .......................................................................20 3.1 Design temperature .......................................................................... 21 3.2 Temperature for machinery systems and equipment.............................. 21 3.3 Cooling water temperatures ............................................................... 21 3.4 Humidity ......................................................................................... 21 3.5 Performance ................................................................................... 21 3.6 Inclinations...................................................................................... 22 3.7 Vibrations ....................................................................................... 22 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 4 Contents CONTENTS Sec.1 Sec.2 Metallic materials ....................................................................................... 23 1 General ...................................................................................................23 2 Principles ...............................................................................................23 Structural fabrication .................................................................................. 24 1 General ...................................................................................................24 2 Plans and data to be submitted ..............................................................24 CH. 4 HULL AND EQUIPMENT............................................. 25 Sec.1 Sec.2 Structural design......................................................................................... 25 1 General ...................................................................................................25 1.1 Introduction..................................................................................... 25 1.2 Scope ............................................................................................. 25 1.3 Plans and data to be submitted .......................................................... 25 2 Principles................................................................................................27 3 Analysis and calculations........................................................................28 3.1 General ........................................................................................... 28 3.2 Fatigue analysis ............................................................................... 28 4 Design and loading conditions ................................................................28 4.1 General ........................................................................................... 28 4.2 Environmental conditions .................................................................. 29 4.3 Accidental conditions ........................................................................ 29 5 Loads and load effects ............................................................................30 5.1 General ........................................................................................... 30 5.2 Accidental loads ............................................................................... 30 5.3 Load calculations .............................................................................. 31 6 Structural categorization, material and inspection principles .................31 6.1 Structural categorization.................................................................... 31 6.2 Material selection.............................................................................. 31 7 Structural strength .................................................................................31 7.1 General ........................................................................................... 31 7.2 Footing strength ............................................................................... 32 7.3 Section scantlings............................................................................. 33 7.4 Fatigue strength .............................................................................. 33 8 Weld connections ...................................................................................33 9 Corrosion control ....................................................................................33 Stability and watertight integrity ............................................................... 35 1 General ...................................................................................................35 1.1 Introduction..................................................................................... 35 1.2 Plans and data to be submitted .......................................................... 35 2 Stability ..................................................................................................36 3 Watertight integrity, freeboard and weathertight closing appliances .....36 3.1 General ........................................................................................... 36 3.2 Materials ......................................................................................... 37 3.3 Watertight integrity .......................................................................... 37 3.4 Weathertight closing appliances ......................................................... 37 3.5 Freeboard........................................................................................ 38 3.6 Penetrations .................................................................................... 38 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 5 Contents CH. 3 MATERIALS AND WELDING ...................................... 23 towing......................................................................................................... 39 1 General ...................................................................................................39 1.1 Introduction..................................................................................... 39 1.2 Plans and data to be submitted .......................................................... 39 1.3 Principles......................................................................................... 39 2 Detailed requirements ............................................................................39 2.1 General ........................................................................................... 39 2.2 Material........................................................................................... 40 2.3 Strength analysis.............................................................................. 40 CH. 5 MACHINERY SYSTEMS AND EQUIPMENT .................. 42 Sec.1 Sec.2 Marine, machinery and piping systems........................................................ 42 1 General ...................................................................................................42 1.1 Introduction..................................................................................... 42 1.2 Application....................................................................................... 42 1.3 Plans and data to be submitted .......................................................... 42 2 Principles................................................................................................44 2.1 General ........................................................................................... 44 2.2 Component design ............................................................................ 44 3 Valves.....................................................................................................45 3.1 Design and tests............................................................................... 45 3.2 Installation ...................................................................................... 45 3.3 Operation ........................................................................................ 45 4 Piping .....................................................................................................45 4.1 Design ............................................................................................ 45 4.2 Materials ......................................................................................... 46 4.3 Platform piping................................................................................. 46 4.4 Machinery piping .............................................................................. 48 4.5 Pipe fabrication, workmanship and testing ........................................... 49 5 Rotating machines ..................................................................................49 5.1 Principles......................................................................................... 49 5.2 Diesel engines.................................................................................. 49 5.3 Starting arrangements ...................................................................... 50 5.4 Start from “dead ship”....................................................................... 51 6 Jacking system .......................................................................................51 6.1 General ........................................................................................... 51 6.2 Design principles .............................................................................. 52 6.3 Materials ......................................................................................... 52 6.4 Arrangement.................................................................................... 52 6.5 Electrical systems ............................................................................. 53 6.6 Control and monitoring...................................................................... 53 6.7 Testing and inspection....................................................................... 53 Electrical installations ................................................................................. 55 1 General ...................................................................................................55 1.1 Introduction..................................................................................... 55 1.2 Application....................................................................................... 55 1.3 Plans and data to be submitted .......................................................... 55 2 Principles................................................................................................57 3 Arrangements and installation................................................................57 3.1 Arrangement.................................................................................... 57 3.2 Installation ...................................................................................... 57 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 6 Contents Sec.3 Sec.3 Sec.4 Sec.5 Power supply ..........................................................................................58 4.1 Main ............................................................................................... 58 4.2 Emergency power supply systems ...................................................... 59 4.3 Battery systems ............................................................................... 59 4.4 Power supply to jacking gear.............................................................. 60 5 Electrical power distribution ...................................................................60 6 Protection ...............................................................................................60 7 Control....................................................................................................61 8 Electrical equipment: ..............................................................................61 9 Cables.....................................................................................................61 9.1 Cable selection ................................................................................ 61 9.2 Cable construction and rating ............................................................. 62 9.3 Cable routing and installations............................................................ 62 Area arrangements .................................................................................... 64 1 General ...................................................................................................64 1.1 Scope ............................................................................................. 64 1.2 Plans and data to be submitted .......................................................... 64 2 Divisions and equipment location ...........................................................64 2.1 General ........................................................................................... 64 2.2 Electrical installations ........................................................................ 65 3 Hazardous areas .....................................................................................65 3.1 Area classification ............................................................................. 65 3.2 Battery rooms, paint stores, and welding gas bottle stores .................... 65 3.3 Requirements for specific systems ...................................................... 66 4 Ventilation systems ................................................................................66 5 Marking and signboards..........................................................................67 Control and communication systems and emergency shutdown.................. 69 1 General ...................................................................................................69 1.1 Introduction..................................................................................... 69 1.2 Application....................................................................................... 69 1.3 Plans and data to be submitted .......................................................... 69 2 Principles................................................................................................69 2.1 General ........................................................................................... 69 2.2 Response to failures.......................................................................... 69 3 System design ........................................................................................70 4 Component design and installation .........................................................70 5 User interface .........................................................................................71 6 ESD and emergency control ....................................................................71 6.1 Emergency shut down ....................................................................... 71 6.2 Emergency control ............................................................................ 74 7 Communication and alarms ....................................................................75 7.1 Communication ................................................................................ 75 7.2 Alarms ............................................................................................ 75 Fire protection ............................................................................................ 77 1 General ...................................................................................................77 1.1 Introduction..................................................................................... 77 1.2 Application....................................................................................... 77 1.3 Plans and data to be submitted .......................................................... 77 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 7 Contents 4 Sec.6 Principles................................................................................................78 3 Passive fire protection ............................................................................78 4 Fire 4.1 4.2 4.3 5 Fire and gas detection systems...............................................................80 6 Escape ....................................................................................................80 fighting systems ..............................................................................78 Fire pumps, fire mains, hydrants and hoses ......................................... 78 Active fire protection of specific areas.................................................. 79 Fire fighting systems of specific types.................................................. 79 Enhanced systems....................................................................................... 81 1 Introduction ...........................................................................................81 1.1 General ........................................................................................... 81 1.2 Objective......................................................................................... 81 1.3 Scope ............................................................................................. 81 1.4 Application....................................................................................... 81 1.5 Documentation requirements ............................................................. 81 2 Technical requirements ..........................................................................81 3 Certification of materials and components..............................................82 CH. 6 CERTIFICATION ....................................................... 83 Sec.1 Sec.2 Procedures ................................................................................................. 83 1 Introduction ...........................................................................................83 2 Certification types ..................................................................................83 3 Class involvement...................................................................................83 4 Certification in operation ........................................................................84 Machinery and system certification ............................................................. 85 1 General ...................................................................................................85 2 Principles................................................................................................85 3 Machinery systems and equipment .........................................................86 3.1 General ........................................................................................... 86 3.2 Miscellaneous mechanical components................................................. 86 3.3 Pressure vessels .............................................................................. 87 3.4 Main and emergency power ............................................................... 87 3.5 Jacking machinery ............................................................................ 88 3.6 Components in marine and machinery piping systems ........................... 88 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 8 Contents 2 Electrical installations.............................................................................89 5 Automation and control system ..............................................................92 6 Fire protection ........................................................................................92 7 Watertight/ weathertight integrity.........................................................93 CH. 7 NEWBUILDING SURVEY ........................................... 94 Sec.1 Sec.2 Sec.3 Sec.4 Sec.5 Introduction ................................................................................................ 94 1 Overview ...............................................................................................94 2 Structure ................................................................................................94 3 Principles................................................................................................94 Survey planning .......................................................................................... 95 1 Objective ................................................................................................95 2 Scope......................................................................................................95 3 Quality survey plan.................................................................................95 3.1 Introduction..................................................................................... 95 3.2 Review of the construction facility ....................................................... 95 3.3 New building survey planning ............................................................. 95 Fabrication of structures ............................................................................. 97 1 Principles................................................................................................97 2 Technical provisions ...............................................................................97 3 Certification and classification ................................................................97 Commissioning process ............................................................................... 98 1 Introduction ...........................................................................................98 2 Principles................................................................................................98 3 Process ...................................................................................................98 4 Survey scope categories .........................................................................98 5 Test requirements related to marine, utility and safety systems ............99 6 Jacking trials ..........................................................................................99 Deliverables .............................................................................................. 100 1 Class certificate ....................................................................................100 2 Conditions of class................................................................................100 3 Appendix to class certificate .................................................................100 4 Additional declarations .........................................................................100 5 Statutory certificates ............................................................................100 CH. 8 CLASSIFICATION IN OPERATION ........................... 102 Sec.1 Sec.2 Introduction .............................................................................................. 102 1 Introduction .........................................................................................102 2 Objective ..............................................................................................102 3 Scope....................................................................................................102 General provisions and requirements for surveys .......................................................................... 103 1 Conditions for retention of class ...........................................................103 2 Class involvement.................................................................................103 2.1 General ......................................................................................... 103 2.2 Damage and repairs........................................................................ 103 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 9 Contents 4 Sec.3 Sec.4 Sec.5 Sec.6 Temporary equipment ..................................................................... 103 3 Special provisions for ageing units .......................................................104 3.1 General ......................................................................................... 104 3.2 Corrosion allowance ........................................................................ 104 3.3 Calculation of fatigue life ................................................................. 104 3.4 Follow up....................................................................................... 105 3.5 Additional inspections...................................................................... 105 4 Alternative survey arrangements..........................................................106 5 Surveys performed by approved companies .........................................106 Preparation and planning ........................................................................ 107 1 Preparation...........................................................................................107 2 Planning ...............................................................................................107 2.1 General ......................................................................................... 107 2.2 Periodical surveys ........................................................................... 107 2.3 Specific surveys ............................................................................. 108 2.4 In-service inspection program (IIP)................................................... 108 Periodical surveys ..................................................................................... 111 1 Annual survey.......................................................................................111 1.1 Structure and equipment ................................................................. 111 1.2 Machinery and safety systems .......................................................... 112 1.3 Documentation............................................................................... 114 2 Intermediate survey .............................................................................114 2.1 Structure and equipment ................................................................. 114 2.2 Machinery and systems ................................................................... 115 3 Renewal survey ....................................................................................115 3.1 Extent........................................................................................... 115 3.2 Structure and equipment ................................................................. 115 3.3 Machinery and systems ................................................................... 119 3.4 General ......................................................................................... 122 Other surveys............................................................................................ 123 1 Record keeping ....................................................................................123 2 Bottom survey ......................................................................................123 3 Spudcan and leg survey ........................................................................123 3.1 General ......................................................................................... 123 3.2 Scope ........................................................................................... 123 3.3 Inspection ..................................................................................... 123 4 Survey after ocean transit ....................................................................124 Permanently installed self-elevating units ................................................................................... 125 1 Introduction .........................................................................................125 2 Fatigue .................................................................................................125 3 Inspection and maintenance.................................................................125 3.1 Facilities for survey ......................................................................... 125 3.2 Surveys......................................................................................... 125 3.3 Inspection before re-location............................................................ 126 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 10 Contents 2.3 SECTION 1 GENERAL The classification rules for design and construction of self-elevating units can be found in the applicable requirements of DNV GL offshore standards and service descriptions. Recognizing that these are generic in nature, both in the topics covered and in the actual requirement description, there is an opportunity to construct an abstract of these with a focus on self-elevating unit relevant requirements. SECTION 2 OBJECTIVE The objective of this publication is to give a complete but concise overview of the relevant technical standards and DNV GL’s involvement for building and classing a conventional self-elevating unit. In this objective, the book is to be used in conjunction with DNV GL-RU-OU-0101 and the relevant technical standards as referred to therein. SECTION 3 SCOPE This publication describes the technical and procedural requirements for classification of self-elevating units of a conventional design as covered by main class. Both the description of a conventional design and the scope of main class is further detailed in Ch.2. This publication covers the involvement of class for a unit’s different phases during life time, i.e. design, construction, commissioning, delivery and operation. The publication does not cover the requirements for separate additional class notations, nor the requirements for units of an unconventional design. These are detailed in the Rules for drilling units (ref. DNVGL-RU-OU-0101). This publication does not cover the requirements applicable for units drilling on a fixed platform. SECTION 4 STRUCTURE To maintain a clear overview, these rules consist of references to the relevant DNV GL rules offshore standards and other DNV GL service documents. The degree of reference detail is depending on the nature of the subject. To improve readability and understanding, the references are completed with a direct description of requirements. In special, a description has been included on topics of a higher complexity or risk. The second chapter of these rules describes the principles of classification and its procedures in Sec.1 and Sec.2. The third chapter of this part continues thereafter with the overall technical principles as applicable for the design of a self-elevating unit build under DNV GL classification. The technical requirements together with relevant calculations methods are discussed in detail in Ch.3 to Ch.5. The three parts cover the main technical areas of class, subsequently materials and welding, hull and equipment and machinery and systems. Ch.6 to Ch.8 thereafter give a concise overview for specific phases of class involvement, that is respectively in the component and system certification process, the new building mechanical completion and commissioning and conclusively survey and test requirements in the operational phase after delivery. For a clear separation between the content of this publication and other DNV GL rules, standards or other service documents, references to chapters and sections are related to this publication if not explicitly stated otherwise. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 11 Chapter 1 Section 1 CHAPTER 1 INTRODUCTION 1 Verbal forms Table 1 Verbal forms Term Definition shall verbal form used to indicate requirements strictly to be followed in order to conform to the document should 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 may verbal form used to indicate a course of action permissible within the limits of the document 2 Definitions Table 2 Definitions Term Definition approval or approved denotes acceptance by DNV GL of documentation showing design solutions, arrangements and equipment that complies with the Rules assessment an act of assessing, appraising or evaluating a condition of a product, process or system builder Signifies the party contracted to build a vessel in compliance with the Society's rules certificate a document confirming compliance with the Society's rules or with other rules and regulations for which the Society has been authorized to act certification a service confirming compliance with applicable requirements on the date that the survey was completed certification of materials and components the activity of ensuring that materials, components and systems used in vessels to be classed by the society comply with the rule requirements The scope of classification re-quires that specified materials, components and systems intended for the vessel are certified. Depending on the categorisation, certification may include both plan approval and survey during production and/or of the final product. class class is assigned to and will be retained by vessels complying with applicable requirements of the Society's rules classification a service which comprises the development of independent technical standards for vessels - class rules and standards, and to verify compliance with the rules and standards throughout the vessels' life close-up examination an examination where the details of structural components are within the close visual inspection range of the surveyor, i.e. preferably within reach of hand commissioning a process of assuring that components, equipment and the systems are functioning in accordance with the functional requirements surveys required to be concurrently completed shall have the same date of completion concurrent surveys condition of class condition on behalf of the flag administration A survey required to be carried out in conjunction with or carried out as part of another survey shall be completed on or before the completion of the other survey, however, within the time window for that survey. constitutes a requirement that specific measures, repairs or surveys shall be carried out within a specific time limit in order to retain class constitutes specific measures, repairs or surveys that shall be carried out within a specific time limit in order to retain the statutory certificate A CA will be issued only when the Society has been authorised to carry out statutory surveys on behalf of the flag ad-ministration. the specific agreement between DNV GL and the client It defines the extent of services requested by the customer, and is concerned with: contract critical structural areas — the classification of vessels or installations, both new buildings and in operation — statutory work carried out on behalf of national maritime authorities — equipment and materials. areas that have been identified from calculations to require monitoring or from the service history of the subject vessel or from similar or sister vessels to be sensitive to cracking, buckling or corrosion which would impair the structural integrity of the vessel Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 12 Chapter 1 Section 5 SECTION 5 DEFINITIONS Term Definition customer signifies the party who has requested the Society's service designer signifies a party who creates documentation submitted to the Society for approval or information escape means for leaving the various workplaces on the unit or installation leading to a safe place and without directly entering the sea essential service generally defined as a service which needs to be, in continuous operation for maintaining the unit’s manoeuvrability (if applicable), or whose loss or failure would create an immediate danger to the unit exceptional circumstances unavailability of dry-docking facilities; unavailability of repair facilities; unavailability of essential materials, equipment or spare parts; or delays incurred by action taken to avoid severe weather conditions flag administration the maritime administration of a vessel's country of registry guidance note contain advice which is not mandatory for the assignment or retention of class, but with which the Society, in light of general experience, advises compliance generally defined as a service which needs not necessarily be in continuous operation but whose failure or non-availability would not create an immediate danger but impairs the unit’s safety important services Guidance note: Systems and equipment providing the service above are essential respectively important. This applies also to systems and equipment supporting these like control and electrical systems. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- independent tank self-supporting tank which does not form part of the vessel's hull and does not contribute to the hull strength Independent gravity tank is a tank with design vapour pressure not exceeding 0.7 bar. interpretations load resistance factor design norms for fulfilling the associated principle requirements as defined by other regulatory bodies on matters which are left to the satisfaction of the flag administration or are vaguely worded These do not preclude the use of other alternative solutions but these shall be documented and approved for compliance to the principal requirement equivalent to the original interpretation. structural analysis and design method manufacturer signifies the entity that manufactures the material or product, or carries out part production that determines the quality of the material or product, or does the final assembly of the product mechanical completion verification that the components, equipment and the systems are constructed, installed and tested in accordance with applicable drawings and specifications and are ready for testing and commissioning in a safe manner memorandum to owner constitutes information related to the ship, its machinery and equipment or to rule requirements An MO will be issued in relation to information that does not require any corrective action or survey. overall examination an examination intended to report on the overall condition of the structure plan approval signifies a systematic and independent examination of drawings, design documents or records in order to verify compliance with the rules or statutory requirements a tank within the hull of a self-elevating unit preload tank These tanks are periodically filled with salt water ballast and used to preload the footings of the unit prior to commencing drilling operations. Preload tanks are considered equivalent to Ballast Tanks. pressure vessel a tank with design gas or vapour pressure exceeding 0.5 bar prompt and thorough repair a permanent repair completed at the time of survey to the satisfaction of the surveyor, therein removing the need for the imposition of any associated condition of class quality system signifies both the quality management system and established production and control procedures Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 13 Chapter 1 Section 5 Table 2 Definitions (Continued) Term Definition quality survey plan a plan that systematically identifies activities related to the classification project (e.g., construction, installation, testing, mechanical completion, pre-commissioning, testing and commissioning) and the extent of involvement each party (i.e., yard's QC, yards' QA, DNV GL and owners [if desired]) will undertake Such a plan needs to be submitted to the Society for approval prior to commencement of classification projects. reliability representative tanks the ability of a component or a system to perform its required function under given conditions for a given time interval those tanks which are expected to reflect the condition of other tanks of similar type and service and with similar corrosion protection systems When selecting representative tanks account shall be taken of the service and repair history on board and identifiable critical and/or suspect areas. review signifies a systematic examination of drawings, design documents or records in order to evaluate their ability to meet requirements, to identify any problems and to pro-pose necessary actions safety systems systems needed to be continuous available or available on demand to prevent, to detect, to control or to mitigate the effects of an undesirable event, and to safeguard the personnel, environment and the installation sighting survey a survey to confirm that the relevant construction or the equipment is in a satisfactory condition and, as far as can be judged, will remain so until the postponed survey has been carried out significant repair a repair where machinery is completely dismantled and re-assembled Significant repairs will, furthermore, be cases of repairs after serious damage to machinery. The Society signifies DNV GL safety systems systems, including required utilities, which are provided to prevent, detect/ warn of an accidental event/abnormal conditions and/or mitigate its effects spaces separate compartments including holds and tanks a document confirming compliance with specified requirements statement of compliance Such documents may be issued by the Society in cases where it has not been authorised to certify compliance. statutory certificates IMO convention certificates issued on behalf of, or by, national authorities statutory survey survey carried out by or on behalf of a flag administration substantial corrosion extent of corrosion such that assessment of corrosion pattern indicates wastage in excess of 75% of allowable margins, but within acceptable limits signifies a systematic and independent examination of a vessel, materials, components or systems in order to verify compliance with the rules and/or statutory requirements survey Surveys will be carried out on the vessel, at the construction or repair site as well as at subsuppliers and other locations at the discretion of the Society, which also decides the extent and method of control. suspect areas areas showing substantial corrosion and/or are considered by the surveyor to be prone to rapid wastage temporary conditions design conditions not covered by operating conditions, e.g. conditions during fabrication, mating and installation phases, dry transit phases temporary equipment equipment intended for use on installations and which is covered by class, requires hookup to systems covered by class and/or is a significant deck load and/or may pose a risk for fire, explosion and escape routes transit conditions all wet vessel movements from one geographical location to another Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 14 Chapter 1 Section 5 Table 2 Definitions (Continued) Term Definition transverse section section which includes all longitudinal members such as plating, longitudinals and girders at the deck, side, bottom, inner bottom and hopper side plating, longitudinal bulkhead and bottom plating in top wing tanks, as applicable For transversely framed vessels, a transverse section includes adjacent frames and their end connections in way of transverse sections. verification a service that signifies a confirmation through the provision of objective evidence (analysis, observation, measurement, test, records or other evidence) that specified requirements have been met witnessing signifies attending tests or measurements where the surveyor verifies compliance with agreed test or measurement procedures working stress design structural analysis method 3 Abbreviations The abbreviations in Table 3 are used. Table 3 Abbreviations Abbreviation In full CA condition on behalf of the flag administration CC condition of class CMC certification of materials and components ESD emergency shut down FMEC failure mode effect and criticality analysis FUI fatigue utilisation index IACS The International Association of Classification Societies Unified rules, interpretations, guidelines and recommendations may be found on www.iacs.org.uk. IMO International Maritime Organization HP high pressure ISO International Organisation for Standardization LRFD load resistance factor design MC mechanical completion MO memorandum to owner OEM original equipment manufacturer QSP quality survey plan UT ultrasonic testing WSD working stress design Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 15 Chapter 1 Section 5 Table 2 Definitions (Continued) SECTION 1 CLASSIFICATION PRINCIPLES 1 General General regulations and procedures are described in Rules for drilling units (see DNVGL-RU-OU-0101) Ch.1. Specific requirements and relevant instructions for classing conventional self-elevating units are contained in this rule chapter. Deviation from the requirements may be substituted where shown to provide equivalent or higher level of integrity and safety. Any deviation from the requirements shall be documented and agreed between all contracting parties. For a complete understanding of this chapter is referred to DNVGL-RU-OU-0101. 2 Application These rules are intended for self-elevating units of conventional design, that is: — independent legs — not designed for field- or ocean transits under own power — diesel driven generators — rack and pinion type jacking system. For other types of offshore units and self-elevating units with design alternatives or technical solutions not covered in these rules, see Rules for drilling units. Unless stated otherwise, the coming into force date for these rules and the documents referenced by these Rules as technical basis for classification shall be six (6) months after the date of publication. 2.1 Interpretations 2.1.1 These rules and the technical standard as being referred to are based on internationally accepted principal requirements. In cases where these a) contain only functional requirements b) allow alternative solutions to prescriptive requirements or c) are generally or vaguely worded, a DNV GL interpretation has been added. 2.1.2 The interpretations are not aiming at introducing additional requirements but at achieving uniform application of the principal requirements. The interpretations can be regarded as norms for fulfilling the principle requirements. 2.1.3 The interpretations do not preclude the use of other alternative solutions. Such solutions shall be documented and approved for compliance to the principal requirement equivalent to the original interpretation. 3 Class scope and notations 3.1 Scope Classification follows the technical scope as described in Ch.2 Sec.3 [2] and covers the design, construction, commissioning and operational phases of the unit. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 16 Chapter 2 Section 1 CHAPTER 2 GENERAL REGULATIONS AND CONDITIONS Vessels build under compliance of the requirements and procedures of these rules shall be given the class notation +1A1 Self-elevating Drilling Unit. Table 3-1 lists most relevant additional class notation for non-self-propelled, self-elevating units. A complete list of additional class notations can be found in Rules for drilling units Ch.1 Sec.3 [2.6] and in DNV Rules for classification of ships (DNV Rules for ships) Pt.1 Ch.2. Table 1 Additional class notation for non-self-propelled, self-elevating units Class notation Description Qualifier Description Design requirements CRANE Onboard crane DNV Rules for ships, Pt.6 Ch.1 Sec.3 DRILL Drilling plant DNVGL-OS-E101 E0 Periodically unattended machinery space DNV Rules for ships Pt.6 Ch.3 ECO Machinery centralized operated DNV Rules for ships Pt.6 Ch.3 ES Enhanced control and safety systems Sec.6 HELDK Helicopter deck ISDS Integrated software dependent systems Recyclable Inventory of hazardous materials part 1 S Vessel safety H Helicopter safety F WELL WELLTEST Structure (...) DNVGL-OS-E401 Ch.2 Helicopter facilities See DNVGL-OS D203 for qualifier definitions DNVGL-OS D203 DNV Rules for ships Pt.6 Ch.27 1 Vessel mounted system excluding subsea equipment 2 Vessel mounted system including subsea equipment Well intervention system Well test system DNVGL-OS-E101 DNVGL-OS-E101 Ch.3 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 17 Chapter 2 Section 1 3.2 Notations 1 Plan approval 1.1 Format The documentation for plan approval may be submitted on paper or as an electronic file. Any documents submitted for re-approval or re-examination shall be especially marked to identify the revised parts. Symbols used shall be explained, or reference to a standard code shall be given. Each drawing shall include a title field stating: — name of vessel (when known) — name of document issuing company — name and signature of originator and verifier — document no. — document title — revision no. — issue date — scale — set of measurement units used in the document, e.g. System International. The document title should not include the name of the vessel. The document title should include the function or component covered by the document. Unique revision numbers shall be allocated to all issues of a document, including the first issue. For documents with multiple sheets, the revision number should be the same for all sheets. 1.2 Subcontractors Where subcontractors and suppliers are involved, the customer shall co-ordinate the submission of required plans and documents, as well as co-ordinate any approval comments given by the Society. This does not apply for materials, components and systems requiring certification as is discussed in more detail in Ch.6. 1.3 Plans and data to be submitted General list of plans and data to be submitted are included in the applicable technical chapters of Ch.3 to Ch.5. A detailed and project specific list shall be supplied by DNV GL directly after the class agreement has been signed. Project specific implies that only those documentation is required as is relevant for the design and within the scope of the contractual agreement between yard and DNV GL. 2 Certification The scope of classification requires that specified materials, components and systems intended for the vessel are certified according to the rules. The objective of certification shall ensure that materials, components and systems used in vessels to be classed by the Society comply with the rule requirements. Certification normally includes both plan approval and survey during production and/or of the final product. A detailed description of the certification process and the specific requirements and lists of the specified materials, components and systems is given in Ch.6. 3 Testing and surveys During the building period DNV GL carries out surveys at the building yard and its suppliers. The purpose of these is to verify that the construction, components and equipment satisfy the rule requirements and are in accordance with the approved plans, that required materials are used, and that functional tests are carried out as prescribed by the rules. A complete description of these test and surveys is given in Ch.7. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 18 Chapter 2 Section 2 SECTION 2 PROCEDURES Chapter 2 Section 3 SECTION 3 PRINCIPLES AND CONDITIONS 1 General The table below lists references required for a complete understanding of this chapter. Table 1 Overview of applicable standards Reference Title DNVGL-OS-A101 Safety principles and arrangements DNVGL-OS-D101 Marine and machinery systems and equipment DNVGL-OS-D201 Electrical installations DNVGL-OS-D202 Automation, safety, and telecommunication systems DNVGL-OS-D301 Fire protection 2 Design principles 2.1 Scope These rules with the referred standards give requirements in the following areas: 1) Hull and main structure — strength — materials and welding — corrosion protection — passive fire protection — weathertight and watertight integrity — stability and floatability. 2) Marine and machinery installations and equipment Machinery installations and equipment, including their related auxiliary systems, to the following main functions: — jacking gear — fire extinguishing — drainage and bilge pumping — ballasting — emergency shutdown systems. 3) Systems and equipment provided to prevent, detect/ warn of an accidental event and/or prevent or mitigate its effects 4) Secure integrity of shelter areas and usability of escape ways and means of evacuation 2.2 Safety and important systems To further frame the content of the rules, the above listed areas and systems are split into safety, essential and important systems. Safety systems are systems needed to be continuous available or available on demand to prevent, to detect, to control or to mitigate the effects of an undesirable event, and to safeguard the personnel, environment and the installation. Examples of safety systems covered by main class: — fire pumps — emergency shut down (ESD) system — fire and gas detection and alarm system — systems required to be supplied from batteries or emergency generator, e.g. public address, emergency lighting Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 19 — control, monitoring and safety devices or systems for safety systems. Essential and Important services ensure reliable operation and maintain the units operation within operational limitations. Examples of equipment or systems for important services covered by main class: — fuel oil transfer pumps and fuel oil treatment equipment — seawater pumps (note) — starting air and control air compressors — bilge- and ballast/preload pumps — ventilating fans for engine rooms — ventilating fans for gas dangerous spaces — main lighting system — watertight closing appliances — jacking system — bilge alarm system — electric generators and associated power sources supplying the above equipment — control, monitoring and safety devices or systems for the above equipment — seawater pumps (if used as part of a fire water supply system). 2.3 Redundancy Safety systems are always to be available. To secure that safety systems always are available, the general principle is that components and systems shall be arranged with redundancy so that a single failure of any active component or system does not cause loss of any main function. Availability is as such further indirect defined in the requirement to a system (where this general principle may be waived and/ or where duplication of components is required). Redundancy can either be arranged by installing more than one unit (component redundancy) or by having two or more systems capable of performing the same functions (system redundancy). For redundancy on a component level a single failure of an active component shall not lead to a reduction of the output power for the main function served. When two or more components are performing the same function, these shall be mutually independent and at least one shall be independently driven. Components arranged as part of the designed redundancy, yet only performing important functions to a main unit, can be directly powered by the main unit through separate power transmissions, on the condition that these components are not necessary for the starting of the main unit. When traditional mechanical components are replaced by electronic components, these components shall have the same reliability as the mechanical component being replaced. Machinery or equipment having remote or automatic control, shall have additional alternative provisions for attendance and operation. 2.4 Failure effects In the event of failure, components and systems shall enter the least hazardous of the possible failure states with regard to machinery, personnel and environment. Failure of one component in a system arranged as part of the designed redundancy shall not lead to failure or damage to backup or parallel components or systems. For failure detection see Ch.5 Sec.4 [2.2]. 3 Environmental conditions All components and systems covered by this standard shall be designed to operate under the following environmental conditions unless otherwise specified in the detailed requirements for the component or system. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 20 Chapter 2 Section 3 — electric generators and associated power sources supplying the above equipment The unit’s design temperature is a minimum temperature used as a criterion for the selection of steel grades. The design temperature shall be specified by the customer and shall be taken as the lower or equal to the lowest mean daily temperature in air for the relevant areas. For seasonal restricted operations the lowest mean daily temperature in air for the season may be applied. Guidance note: It is underlined that design temperatures below 0° are only relevant for waters in the higher latitudes (e.g. northern part of North Sea, Canadian waters etc). For these waters and their harsh conditions, relevant considerations should be taken (e.g. DNVGL-OSC201 Ch.2 Sec.1 [2.3.4] on water trapped in local structures, DNVGL-OS-D101 Ch.2 Sec.3 [6.1.8] on freezing of vents, DNVGL-OSD301 in protecting the fire equipment against freezing etc) In addition, class notations related to cold climate operations as listed in Rules for drilling units Ch.1 Sec.3 [2.7] can be relevant as well. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- The design temperature shall be listed in the appendix to Class Certificate (see also Ch.7 Sec.5 [3]). Guidance note: In some offshore standards is, in addition to a design temperature, a service temperature defined. For self-elevating units, the two temperatures are equal. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 3.2 Temperature for machinery systems and equipment Machinery systems and equipment shall be constructed for continuous operation in the range of ambient temperatures as specified in the table below. Table 2 Location Minimum ambient air temperature range for continuous operation (°C) 1 Engine rooms, boiler rooms, galleys and similar spaces, accommodation spaces. 2 Open deck, deckhouses and similar spaces which are not provided with space heating. From To 0 +451 -25 +45 1 Where equipment is installed within environmentally controlled spaces the ambient temperature for which the equipment shall be suitable may be reduced from 45°C and maintained at a value not less than 35°C provided: — the equipment is not for use for emergency services, and shall not be in operation after ESD has been activated — temperature control is achieved by at least two cooling units so arranged that in the event of loss of one cooling unit, for any reason, the remaining unit(s) is capable of satisfactorily maintaining the design temperature — the equipment can be started in a 45°C ambient temperature and kept in operation until the lesser ambient temperature may be achieved — the cooling equipment shall be rated for a 45°C ambient temperature — malfunction of, or loss of a cooling unit shall be alarmed at a manned control station. In accepting a lesser ambient temperature than 45°C, it shall be ensured that electrical cables for their entire length are adequately rated for the maximum ambient temperature to which they are exposed along their length. (see IACS UR E19) For the different environmental classes and the specified temperature ranges as applicable for control- and communication equipment see DNVGL-OS-D202 Ch.2 Sec.4 [2]. 3.3 Cooling water temperatures Electrical equipment shall be constructed for continuous operation under full rated load, at a seawater temperature range from 0 to +32°C. 3.4 Humidity All equipment shall be constructed to withstand, and function safely in relative humidity up to 95%. 3.5 Performance For performance requirements of machine systems, the conditions of Table 3 can be applied (see IACS UR Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 21 Chapter 2 Section 3 3.1 Design temperature Table 3 Parameter Value Total barometric pressure 1 bar Ambient air temperature 45°C Relative humidity of air 60% Sea water temperature 32°C 3.6 Inclinations All machinery, components and systems essential for safe operation shall be designed for operation under the following inclination values: — inclination 10° from normal level in any direction under normal static conditions — inclination 15° from normal level in any direction under normal dynamic conditions. Guidance note: Other values may be accepted if justified by calculations for the particular offshore unit. National authorities may require larger inclinations. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 3.7 Vibrations Electrical equipment and components shall be constructed to withstand, without malfunctioning, or electrical connections loosening, at least a vibration frequency range 5 to 50 Hz with vibration velocity amplitude 20 mm/s. For flexible mounted equipment, special considerations shall be given to the construction of the equipment since larger vibrations may occur. For control- and communication equipment vibration requirements see DNVGL-OS-D202 Ch.2 Sec.4 [2]. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 22 Chapter 2 Section 3 M28): Chapter 3 Section 1 CHAPTER 3 MATERIALS AND WELDING SECTION 1 METALLIC MATERIALS 1 General The table below lists references required for a complete understanding of this chapter. Table 1 Overview of applicable standards Reference Title DNVGL-OS-C101 Design of offshore steel structures, general (LRFD Method) DNVGL-OS-C201 Structural design of offshore units (WSD method) DNVGL-OS-C301 Stability and watertight integrity DNVGL-OS-D101 Marine and machinery systems and equipment DNVGL-OS-E301 Position mooring 2 Principles Principles for certification of steels for structural application are given by standard DNVGL-OS-B101. Requirements for the specific materials selections are given in the technical chapters of Ch.4 and Ch.5 of this book: Table 2 Overview of further details on certification of steel Topic In this rule book Offshore standard Structural steel Ch.4 Sec.1 [6.2] DNVGL-OS-C101 Ch.2 Sec.3 [4] or DNVGL-OS-C201 Ch.2 Sec.3 [4] DNVGL-OS-C104 Ch.2 Sec.1 [3] or DNVGL-OS-C201 Ch.2 Sec.11 [2.3]1) Watertight Integrity, Freeboard and Weathertight Closing Appliances Towline fastening devices and their supporting structures DNVGL-OS-C301 Ch.2 Sec.2 [2] Ch.4 Sec.3 [2.2] DNVGL-OS-C101 Ch.2 Sec.3 Anchors DNVGL-OS-E301 Ch.2 Sec.4 Windlasses, winches and chain stoppers DNVGL-OS-E301 Ch.2 Sec.2 [11.4] Materials for piping Ch.5 Sec.1 [4.1] Jacking gear Ch.5 Sec.1 [6.3] DNVGL-OS-D101 Ch.2 Sec.2 [2] 1) For the use of DNVGL-OS-C104 or the C201 see Sec.1 When material other than steel and aluminium alloys (evidenced by previous service experience) is used in structural fabrication and for equipment relating to main class, documentation of the material’s applicability for intended purpose shall be documented with due regard to the material’s mechanical properties and its responding service performances. Materials with low heat resistance shall not be used in components where fire may cause outflow of flammable or toxic fluids, flooding of any watertight compartment or destruction of watertight integrity. Guidance note: Materials with high heat resistance are materials having a melting point greater than 925°C. Materials with low heat resistance are all other materials. Deviations from the above requirement will be subject to special considerations. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 23 1 General Principles and requirements for structural fabrication are given by standard DNVGL-OS-C401 as discussed in detail in Sec.3. 2 Plans and data to be submitted Plans necessary to assess the joints and welding shall be submitted and approved before steel cutting. A general overview of the content of the plans and analyses is listed in Table 1. A more detailed overview, tuned to the specific design and project scope can be obtained from DNV GL’s Nauticus Production System. Documentation shall be submitted as required by Table 1. Table 1 Documentation requirements Object Structural fabrication Welding Documentation type Additional description Info H140 – Standard details FI M060 – Non-destructive testing (NDT) plan AP M061 – Holes and cutouts plan FI H140 – Welding tables AP M060 – Welding procedures AP M061 – Welding procedure qualification record AP For general requirements to documentation, including definition of the Info codes, see DNVGL-CG-0168 Sec.1. For a full definition of the documentation types, see DNVGL-CG-0168 Sec.2. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 24 Chapter 3 Section 2 SECTION 2 STRUCTURAL FABRICATION Chapter 4 Section 1 CHAPTER 4 HULL AND EQUIPMENT SECTION 1 STRUCTURAL DESIGN 1 General 1.1 Introduction The table below lists references required for a complete understanding of this chapter. Table 1 Overview of applicable standards Reference Title DNVGL-OS-A101 Safety Principles and Arrangement DNVGL-OS-C104 Structural Design of Self Elevating Units (LRFD method) DNVGL-OS-C201 Structural Design of Offshore Units (WSD method) DNVGL-OS-C401 Fabrication and Testing of Offshore Structures DNVGL-OS-D101 Marine and Machinery Systems and Equipment DNVGL-RP-C104 (recommendations for the strength analyses of main structures of) Self-elevating units DNV-RP-C204 Design Against Accidental Loads DNV-RP-C205 Environmental Conditions and Environmental Loads 1.2 Scope The classification scope includes the following structural elements: — barge hull — jacking houses — legs with spudcan — superstructure — crane pedestals (below slewing ring) — support for lifting equipment — cantilever including drill floor (up and including support stools for derrick) — attachment of helideck support structure — foundation and support for heavy equipment (i.e. equipment where the static forces exceed 50 kN or resulting static bending moments at deck exceed 100 kNm). The scope may be extended by the selection of additional voluntary notations. Excluded from the scope are: — Ice and soil conditions — Earthquake and other environmental events defined by an annual probability equal or lower than to 10-4. Transit conditions are included in the structural design scope of work. Temporary conditions are not included unless specifically specified. 1.3 Plans and data to be submitted Plans necessary to assess the strength of the structure including the details of the joints and welding shall be submitted and approved before steel cutting. A general overview of the content of the plans and analyses is listed in Table 2. A more detailed overview, tuned to the specific design and project scope can be obtained Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 25 Table 2 Documentation requirements Object Sacrificial anodes Documentation type Additional description C030 – Detailed drawing Fastening of anodes in ballast tanks AP C030 – Detailed drawing Fastening of anodes in liquid cargo tanks, for cargo with flash point below 60 °C, and adjacent tanks AP M050 – Cathodic protection specification, calculation and drawings Z030 – Arrangement plan Vessel arrangement FI In ballast tanks, in/on spudcans FI H010 – Structural design brief FI Including cantilever load chart Legs Leg > Lattice leg chord racks FI H040 – Structural categorisation plan AP H041 – Structural inspection plan AP Elevated survival, preloading and operating conditions FI H081 – Global strength analysis Temporary conditions, e.g. leg bottom impact, jacking FI H081 – Global strength analysis Operation in partly submerged condition FI H081 – Global strength analysis Transit conditions FI H090 – Model test documentation Required for novel designs, or unproven applications of designs where limited or no direct experience exists Accommodation module structure FI; R H120 – Docking arrangement plan FI H132 – Tank testing plan AP H050 – Structural drawing H080 – Strength analyses AP Including connections to the legs FI H085 – fatigue analysis FI H050 - Structural drawing AP H080 – Strength analyses Including transit and elevated conditions FI H085 – Fatigue analysis Including transit and elevated conditions FI C060 – Mechanical component documentation AP H050 – Structural drawing Including decks, bottom, external- and internal bulkheads AP H080 – Strength analyses Including variable functional loads and equipment (variable and fixed) loads on deck structures, and combinations of global and local stresses FI H050 – Structural drawing FI H080 – Design analyses AP H085 – fatigue analysis Deck Houses AP H081 – Global strength analysis Hull Cantilevers FI H030 – Tank and capacity plan H050 – Structural drawing Leg foundations AP Z010 – General arrangement plan H020 – Design load plan Self elevating unit structure Info Connections to hull FI H050 – Structural drawing FI H080 – Design analyses FI H080 – Design analyses AP Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 26 Chapter 4 Section 1 from DNV GL’s Nauticus Production System. Object Documentation type Accommodation module H050 – Structural drawing AP Accommodation module substructure H050 – Structural drawing AP H050 – Structural drawing AP Jackhouses (incl. Fixation system support and jacking system support) Supporting structures for: — Helicopter deck — Accommodation module — Derrick — Drill floor — Lubrication oil — independent tanks drilling fluid return trip independent tanks — Main generator — Auxiliary boiler — Auxiliary feed water — independent tanks — Helicopter fuel storage tanks — Ballast pumping unit — Internal watertight door/ ramp — Anchor winch1 Anchor chain stopper1 — Anchor fairlead structure1 — Passive towing equipment2 — Offshore crane1 — Sea chests — Offshore crane pedestal Jackhouses 1Applicable 2 Additional description H080 – Strength analyses H085 – fatigue analysis Including footprint. Including hull structures adjacent to legs and jackhouses Info FI FI if static force > 50 kN or bending moment > 100 kNm. Including towing force design loads and winch load footprint For general requirements to documentation, including definition of the Info codes, see DNVGL-CG-0168 Sec.1 and Sec.2. 2 Principles The unit or installation shall be designed and constructed with sufficient integrity to withstand operational and environmental loading throughout its life-cycle. Systems and structures shall be designed with suitable functionality and survivability for prevention of, or protection from, design accident events affecting the unit or installation. Refer also DNV-RP-C204 - Design Against Accidental Loads. The structure shall be designed to resist relevant loads associated with conditions that may occur during all stages of the life-cycle of the unit. The conditions that should be considered are: — transit condition(s) — installation condition — operating condition(s) — survival condition Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 27 Chapter 4 Section 1 Table 2 Documentation requirements (Continued) Both the Load resistance factor design (LRFD) and the Working stress design (WSD) methods are acceptable for structural design and analysis. DNVGL-OS-C104 should be used as reference standard if the LRFD method is adopted, supplemented by general requirements from DNVGL-OS-C101 (where referenced). DNVGL-OS-C201 should be used for WSD method. In the remaining of this chapter, reference to both standards are given for completeness. 3 Analysis and calculations 3.1 General Structural analysis shall be performed to evaluate the structural strength due to global and local effects as described in DNVGL-OS-C104 Ch.2 Sec.2 [4] or DNVGL-OS-C201 Ch.2 Sec.11 [5] as listed in the table below. Table 3 Description Reference in DNVGL-OS-C104 Ch.2 Sec.2 Reference in DNVGL-OS-C201 Ch.2 Sec.11 General [4.1] [5.1] Global structural models [4.2] [5.2] Local structural models [4.3] Fatigue [5.3] See [3.2] below Recommended methods for analysis and calculations are described by DNVGL-RP-C104. 3.2 Fatigue analysis A fatigue strength analysis according to DNVGL-OS-C104 Ch.2 Sec.5 or DNVGL-OS-C201 Ch.2 Sec.6 and DNVGL-OS-C201 Ch.2 Sec.11 [8] shall be undertaken for members and joints for which fatigue fracture is possible mode of failure. For conventional jack-ups the following areas shall normally be assessed: — spudcans and leg at the leg-to spudcan connection — leg and hull/jacking structure at and around the leg-to-hull connections — joints and members of legs (e.g. span breakers) located at and around the splash zone. The required models and methods for fatigue analysis for self-elevating units are dependent on type of operation, environment and design type of the unit. For units operating at deeper waters where the first natural periods of the unit are within the range of significant wave energy, the associated dynamic structural responses shall be considered in the fatigue analysis. The design fatigue life for the structure components should be based on the structure service life specified. If a service life is not specified, 20 years should be used. 4 Design and loading conditions 4.1 General Each structural member shall be designed for the least favourable of the loading conditions given in the table below. Table 4 Case Description a) functional loads Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 28 Chapter 4 Section 1 — retrieval condition. (Continued) b) maximum combination of environmental loads and associated functional loads c) accidental loads and associated functional loads d) annual most probable value of environmental loads and associated functional loads after credible failures, or after accidental events e) annual most probable value of environmental loads and associated functional loads in a heeled condition corresponding to accidental flooding Relevant loading conditions for the different design condition are shown in Table 5. Table 5 Design conditions Transit Loading conditions a) b) x x Installation c) d) Reference e) x x DNVGL-OS-C104 Ch.2 Sec.2 [2.2] or DNVGL-OS-C201 Ch.2 Sec.11 [3.2] DNVGL-OS-C104 Ch.2 Sec.2 [2.3] or DNVGL-OS-C201 Ch.2 Sec.11[3.3] Operation x x Survival x x DNVGL-OS-C104 Ch.2 Sec.2 [2.4] or DNVGL-OS-C201 Ch.2 Sec.11 [3.4] x DNVGL-OS-C104 Ch.2 Sec.2 [2.3] or DNVGL-OS-C201 Ch.2 Sec.11 [3.3] Retrieval x x DNVGL-OS-C104 Ch.2 Sec.2 [2.4] or DNVGL-OS-C201 Ch.2 Sec.11 [3.4] Load cases shall be established for the various design conditions based on the least favourable combinations of functional loads, environmental loads and/or accidental loads. Limiting environmental and operating conditions (design data) for the different design conditions shall be specified by owner or designer. Limiting design criteria for going from one design condition to another shall be specified by owner or designer and be clearly established and documented. If the unit is intended to be dry docked, the footing structure (i.e. spudcans) and/or the barge shall be suitably strengthened to withstand the loads. 4.2 Environmental conditions Environmental conditions for design of self-elevating units are given by DNVGL-OS-C104 Ch.2 Sec.3 [4] or DNVGL-OS-C201 Ch.2 Sec.11 [4]. Combination of loads are given in DNVGL-OS-C104 Ch.2 Sec.3 or DNVGL-OS-C201 Ch.2 Sec.2 [6] and DNVGL-OS-C201 Ch.2 Sec.11 [6.12]. In conjunction with combination of environmental loads for loading condition b) (see DNVGL-OS-C104 Ch.2 Sec.3, DNVGL-OS-C104 Ch.2 Sec.4 [4.2.1] or DNVGL-OS-C201 Ch.2 Sec.2 [6.1.4]) the sustained wind velocity, i.e. the 1 minute average velocity, shall be used. If gust wind alone is more unfavourable than sustained wind in conjunction with wave forces, the gust wind velocity shall be used. For local load calculations gust wind velocity shall be used. Principles and formulas for calculation of wind loads may be taken from DNV-RP-C205 Sec.2. Guidance note: For units intended for unrestricted service (worldwide operation) a wind velocity of not less than 51.5 m/s (v1min10) combined with maximum wave forces will cover most locations. The corresponding wind force should be based on a wind velocity profile given by DNVRP-C205 [2.3.2.12], or equivalent. See also the guidance given in DNVGL-RP-C104 [2.4]. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 4.3 Accidental conditions The overall objective for design with respect to accidental conditions is that unit's main safety functions shall not be impaired by accidental events. Satisfactory protection against accidental damage may be achieved by two barriers: Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 29 Chapter 4 Section 1 Table 4 — reduction of damage consequences. The design against accidental loads may be done by direct calculation of the effects imposed by the loads on the structure, or indirectly, by design of the structure as tolerable to accidents. Examples of the latter are compartmentation of floating units which provides sufficient integrity to survive certain collision scenarios without further calculations. Guidance note: Recommendations for design of structures exposed to accidental events can be found in DNV-RP-C204. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- General requirements for accidental events are given by DNVGL-OS-C104 and DNVGL-OS-C201 as listed in Table 6. Table 6 Description Reference in DNVGL-OS-C104 Ch.2 Sec.6 Reference in DNVGL-OS-C201 Ch.2 [2] Sec.11 [9.2] Collisions Dropped objects [3] Sec.7 [2.3] Fire [4] Sec.11 [9.4] Explosions [5] Sec.7 [2.5] Unintended flooding [6] Sec.11 [9.6] Technical requirements given in DNVGL-OS-C104 or DNVGL-OS-C201 related to design for earthquake of mobile self-elevating drilling units are not mandatory as part of classification. For the loads taken into account for accidental conditions see Sec.1 [5.2]. 5 Loads and load effects 5.1 General Loads and load effects are given by DNVGL-OS-C104 and DNVGL-OS-C201 as listed in the table below. Table 7 Description Permanent functional loads Variable function loads Reference in DNVGL-OS-C104 Ch.2 Sec.3 Reference in DNVGL-OS-C201 Ch.2 [2] Sec.2 [3] and Sec.11 [6.2] [3] Sec.2 [4] and Sec.11 [6] [3.3] Sec.2 [4.3] and Sec.11 [6.5] Environmental loads [4] Sec.2 [5] and Sec.11 [6.5] to [6.11] Accidental loads [6] Sec.2 [7] Tank loads Deformation loads [5] Sec.2 [8] Fatigue loads [7] Sec.6 and Sec.11 [8] 5.2 Accidental loads Accidental loads shall be taken into consideration. The loads shall be based on an individual frequency of occurrence in the order of 10-4 per year, corresponding to an overall frequency of 4 × 10-4 per year as the impairment frequency limit. The generic accidental loads are given by DNVGL-OS-A101, DNVGL-OS-C201 and DNVGL-OS-C301 as detailed in Table 8. Table 8 Description Reference in DNVGL-OS-A101, DNVGL-OS-C104, DNVGL-OS-C201 and DNVGL-OS-C301 Dropped objects DNVGL-OS-A101 Sec.2 [4.2] and DNVGL-OS-C201 Ch.2 Sec.7 [2.3] Collision loads DNVGL-OS-A101 Sec.2 [4.3] and DNVGL-OS-C201 Ch.2 Sec.7 [2.2] Unintended flooding DNVGL-OS-C301 Ch.2 Sec.1 [5.1] and [5.3] Explosions loads DNVGL-OS-A101 Sec.2 [4.6] and DNVGL-OS-C201 Ch.2 Sec.7 [2.5] Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 30 Chapter 4 Section 1 — reduction of damage probability Load calculations are described in DNVGL-OS-C104 Ch.2 Sec.2 [4] and DNVGL-OS-C201 Ch.2 Sec.11 [5]. Guidance can be found in DNVGL-RP-C104. 6 Structural categorization, material and inspection principles 6.1 Structural categorization Application categories for structural components are defined in DNVGL-OS-C104 Ch.2 Sec.1 and DNVGLOS-C201 Ch.2 Sec.3. Structural members of self-elevating units with separate footing are normally found in the following groups: a) Special category — Areas of concentrated stresses in elements of bottom of leg, including leg connection to spudcan. — Intersections of lattice type- or trussed leg structure, which incorporates novel construction, including the use of steel castings. — Areas of concentrated stresses in elements of guide structures, jacking and locking system(s), jackhouse and support structure. — Areas of concentrated stresses in elements of supporting structures to other heavy substructures like cantilever, crane pedestal etc. b) Primary category — Combination of bulkhead, deck, side and bottom plating within the hull which forms “Box” or “I” type acting as main beam — All components of lattice type legs and external plating of cylindrical legs. — Jackhouse supporting structure and bottom footing structure, which receives initial transfer of load from legs. — Internal bulkheads, shell and deck of spudcan which are designed to distribute major loads, either uniform or concentrate. — Main support structure of heavy substructures and equipment, e.g. cranes, drill floor substructure, life boat platform and helicopter deck. c) Secondary category — Deck, side and bottom plating of hull except areas where the structure is considered primary or special application. — Bulkheads, stiffeners, decks and girders in hull that are not considered as primary or special application. — Internal bulkheads and girders in non-trussed legs. — Internal bulkheads, stiffeners and girders of spudcan structures, except where the structures are considered primary or special application. 6.2 Material selection General requirement to material selection are given by DNVGL-OS-C104 Ch.2 Sec.1 [3] and DNVGL-OSC201 Ch.2 Sec.3 [4]. For rack- and chord plates with specified minimum yield stress equal to 690 N/mm2 in rack and pinion jacking systems steel grade VL E690, is acceptable for rack- and chord plates with thickness up to 250 mm and for service temperature down to -20°C. 7 Structural strength 7.1 General General requirements for LRFD design are given by DNVGL-OS-C101 Ch.2 Sec.4 to Sec.7 for each limit Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 31 Chapter 4 Section 1 5.3 Load calculations General requirements for WSD design are given by DNVGL-OS-C201 Ch.2 Sec.4 with specific considerations for Self-Elevating units in Sec.11 [7]. Detailed references are as listed in the table below. Table 9 Description Flat Plated Structures and Stiffened Panels Reference in DNVGL-OS-C101 and C104 Reference in DNVGL-OS-C201 Ch.2 DNVGL-OS-C101 Ch.2 Sec.4 [2] Sec.4 [2] Shell Structures DNVGL-OS-C101 Ch.2 Sec.4 [3] Sec.4 [3] Tubular Members, Tubular Joints and Conical Transitions DNVGL-OS-C101 Ch.2 Sec.4 [4] Sec.4 [4] Non-Tubular Beams, Columns and Frames DNVGL-OS-C101 Ch.2 Sec.4 [5] Sec.4 [5] Strength of Plating and Stiffeners DNVGL-OS-C101 Ch.2 Sec.4 [6] Sec.5 [2] Bending and Shear in Girders DNVGL-OS-C101 Ch.2 Sec.4 [7] Sec.5 [3] Global capacity DNVGL-OS-C104 Ch.2 Sec.4 [2.1] Sec.11 [7.2] Footing strength DNVGL-OS-C104 Ch.2 Sec.4 [2.2] Sec.11 [7.3] Leg strength DNVGL-OS-C104 Ch.2 Sec.4 [2.3] Sec.11 [7.4] Jackhouse support strength DNVGL-OS-C104 Ch.2 Sec.4 [2.4] Sec.11 [7.5] Hull strength DNVGL-OS-C104 Ch.2 Sec.4 [2.5] Sec.11 [7.6] 7.2 Footing strength Spud cans shall be designed by taking into account the effect of uneven distribution from seabed conditions and scouring. The strength checks for the spudcan, the leg-to-spudcan connections and the two lowest leg bays (lattice legs) for separate type spudcans should normally not be based on lower loads than given below: M e = 0 .425 Fv R qc = i) Fv 0.5πR 2 The design load Fv is evenly distributed over 50% of the bottom area: and, q = design contact pressure Me = design eccentricity moment Fv = maximum design axial load in the leg accounting for functional loads and environmental overturning loads. R = equivalent radius of spudcan contact area ii) The design load Fv is concentrically distributed over a range of bearing areas, from the minimum design penetration (supported on spudcan tip) up to and including full spudcan bottom area. iii) If elevated condition is designed based on pinned leg footings; the spudcan and the leg-to-spudcan connections shall be designed for the maximum vertical reaction and the associated horizontal reaction in conjunction with 35% of the maximum calculated moment at the lower guide (to account for the eccentric effects of possible scour and uneven bottom conditions) acting in the most unfavourable direction. The maximum lower guide bending moment shall be calculated with pin-ended conditions. iv) If elevated condition is designed based on moment fixity at leg footings: — The maximum vertical reaction, in conjunction with the associated horizontal reaction and spudcansoil fixity moment, acting in the most unfavourable direction. — The maximum spudcan-soil fixity moment in conjunction with the associated vertical and horizontal reactions, acting in the most unfavourable direction. — The design moments and soil pressures above are based on a relative homogenous seabed, for example for sand or clay seabed. Local stiff soil supporting in the bottom plate outside the strong tip should be avoided. It is assumed that this will be evaluated in the sea bed surveys in connection Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 32 Chapter 4 Section 1 state, with specific considerations for Self-Elevating units in DNVGL-OS-C104 Ch.2 Sec.4 to Sec.6. Guidance note: Cases (i) and (ii) above should always be checked together with one of the cases (iii) or (iv). Case (iii) or (iv) is checked based on the leg footing assumption used in design. For classification the design values in (i) to (iv) will be included in the “Appendix to Class Certificate” as basis for design of the spudcan and lower leg. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- For other types of bottom support, e.g. mats special considerations should be made. 7.3 Section scantlings The requirements in this section are applicable for: — plate thicknesses and local strength of panels — simple girders — calculations of complex girder systems. Requirements are given in DNVGL-OS-C101 Ch.2 Sec.4 [6] or DNVGL-OS-C201 Ch.2 Sec.5 [2] for Strength of plating and stiffeners, and DNVGL-OS-C101 Ch.2 Sec.4 [7] or DNVGL-OS-C201 Ch.2 Sec.5 [3] for Bending and shear in Girders. 7.4 Fatigue strength For units intended to follow normal inspection requirements according to class requirements, i.e. 5 yearly inspections in dry dock or sheltered waters, a Design Fatigue Factor (DFF) of 1.0 may be applied for accessible members. For not accessible members DFF shall be applied to structural elements according to the principles in DNVGL-OS-C201 Ch.2 Sec.6 [1.2]. Units intended to operate continuously at the same location for more than 5 years, i.e. without planned dry dock or sheltered water inspection, shall comply with the requirements given in Pt.7 Ch.6. Requirements for fatigue strength is given by DNVGL-OS-C104 Appendix A or DNVGL-OS-C201 Ch.2 Sec.6 [1], [2] and [3] and Sec.11 [8]. Relevant fatigue analysis are given in Sec.1 [3.2] of this chapter. 8 Weld connections Requirements for weld connections is given by DNVGL-OS-C101 Ch.2 Sec.8 or DNVGL-OS-C201 Ch.2 Sec.8 as listed in the table below. Table 10 Description Reference in DNVGL-OS-C101 or DNVGL-OS-C201 Butt joints Ch.2 Sec.8 [2.1] Tee or cross joints Ch.2 Sec.8 [2.2] Slot welds Ch.2 Sec.8 [2.3] Lap joint Ch.2 Sec.8 [2.4] Weld size Ch.2 Sec.8 [3] 9 Corrosion control Corrosion control of structural steel for offshore structures comprises: — coatings and/or cathodic protection — use of a corrosion allowance — inspection/monitoring of corrosion — control of humidity for internal zones (compartments). Requirements for corrosion control are given by DNVGL-OS-C101 Ch.2 Sec.9 or DNVGL-OS-C201 Ch.2 Sec.9 as listed in Table 11. The manufacturing/installation of systems for corrosion control are covered in Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 33 Chapter 4 Section 1 with site specific assessments when the unit is used on specific locations. Table 11 Description Reference in DNVGL-OS-C101 or DNVGL-OSC201 Techniques for Corrosion Control Related to Environmental Zones Ch.2 Sec.9 [2] Cathodic Protection Ch.2 Sec.9 [3] Coating Systems Ch.2 Sec.9 [4] Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 34 Chapter 4 Section 1 DNVGL-OS-C401 Sec.5. STABILITY AND WATERTIGHT INTEGRITY 1 General 1.1 Introduction This section provides principles, technical requirements and guidance related to stability, watertight integrity, freeboard and weathertight closing appliances. The table below lists references required for a completed understanding of this chapter. Table 1 Overview of applicable standards Reference Title IMO MODU Code Code for the construction and equipment of Mobile Offshore Drilling Units, 2009 ICLL 1966 International Convention on Load Lines, 1966, amended by Protocol 1988 DNVGL-OS-B101 Metallic materials DNVGL-OS-C301 Stability and watertight integrity DNV-Rules for Ships Pt.6 Ch.9 Loading Computer Systems (LCS) for Stability and Longitudinal Strength DNVGL-OS-D101 Marine and machinery systems and equipment 1.2 Plans and data to be submitted A general overview of the content of the plans and analyses is listed in Table 2. A more detailed overview, tuned to the specific design and project scope can be obtained from DNV GL’s Nauticus Production System. Table 2 Documentation requirements Object Stability Damage stability Documentation type Additional description Info B010 – Lines plan and offset tables FI B020 – External watertight integrity plan FI B040 – Stability analysis AP B050 – Preliminary stability manual AP B100 – Inclining test and lightweight survey procedure AP B110 – Final stability manual AP B030 – Internal watertight integrity plan FI B070 – Preliminary damage stability calculation AP External watertight and weathertight integrity B200 – Freeboard plan AP Internal watertight door / ramp Z030 – Arrangement plan Applicable for all watertight doors. Including for each door: Size, design principle (sliding, hinged), pressure rating and fire rating. Including remote control positions. AP AP Internal watertight doors / ramps hydraulic power system S010 – Piping diagram Internal watertight doors > Door structure C030 – Detailed drawing Service hatchways C010 – Design criteria FI Ventilation System S012 – Ducting diagram AP AP For general requirements to documentation, including definition of the Info codes, see DNVGL-CG-0168 Sec.1. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 35 Chapter 4 Section 2 SECTION 2 2 Stability This section gives requirements related to the following design parameters: 1) Buoyancy and floatability. 2) Wind exposed portions. 3) Draught range at various modes of service. 4) Lightweight and loading conditions. The combination of the design parameters (1 to 4) will determine the maximum allowable vertical centre of gravity (VCG) of the unit at the applicable service draughts and modes. In order to determine VCG of the actual loading conditions, the lightweight and its centre of gravity must be known. This shall be obtained by an inclining test carried out in accordance with IMO MODU Code, 2009. Table 3 Description Reference Determination of Lightweight IMO MODU Code, 2009, Regulation 3.1 Determination of wind forces: IMO MODU Code, 2009, Regulation 3.2 Intact Stability Requirements: IMO MODU Code, 2009, Regulation 3.3 Damage Stability Requirements: IMO MODU Code, 2009, Regulation 3.4 1), 2) 1) The internal subdivision shall be adequate to enable the unit or installation to comply with the damage stability requirements 2) The following permeability factors shall be assumed in the calculations: — Store rooms: 0.60 — Engine room: 0.85 — Tanks, void spaces etc: 0.95 Other permeabilities may be accepted if documented by calculations. Loading computers for stability calculation shall be considered as supplementary to the stability manual or the stability part of the operation manual. If onboard computers for stability calculations are installed, these systems shall be approved in accordance with requirements in DNV Rules for ships Pt.6 Ch.9. 3 Watertight integrity, freeboard and weathertight closing appliances 3.1 General Watertight closing appliances are required for those external openings being submerged at least up to an angle of heel equal to the first intercept in intact or damage condition, whichever is greatest. Weathertight closing appliances are required for those external openings being submerged at least up to an angle of heel equal to the dynamic angle. This applies to any opening within 4.0 m above the final waterline as well. Ducts or piping, which may cause progressive flooding in case of damage, shall generally not be used in the damage penetration zone. Location of openings where watertight and weathertight integrity are required, are illustrated in DNVGL-OSC301 Ch.2 Sec.2 [10]. The requirements for operation and locking of doors and hatch covers are given in DNVGL-OS-C301 Ch.2 Sec.2 [10]. For Testing of doors and hatch covers ref. DNVGL-OS-C301 Ch.2 Sec.2 [9]. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 36 Chapter 4 Section 2 For a full definition of the documentation types, see DNVGL-CG-0168 Sec.2. Materials and material certificates for: — rolled steel for structural applications and pressure vessels — steel tubes, pipes and fittings — steel forgings — steel castings — aluminium alloys, shall comply with the requirements given by DNVGL-OS-B101 unless otherwise stated in the relevant technical reference documents. Stainless steel shall be with a maximum carbon content of 0.05%. The stainless steel material shall be of the white pickled and passivated condition. Aluminium shall be of seawater resistant type. 3.3 Watertight integrity The number of openings in watertight subdivisions shall be kept to a minimum compatible with the design and proper working of the unit or installation. Where penetrations of watertight decks and bulkheads are necessary for access, piping, ventilation, electrical cables etc., arrangements shall be made to maintain the watertight integrity of the enclosed compartments. Piping and electrical systems for operation of watertight closing appliances shall be in accordance with relevant requirements given in DNVGL-OS-D101 unless otherwise specified in this section. The strength and arrangement of sliding doors and hatch covers and their frames as well as the capacity of the closing systems shall be sufficient to ensure efficient closing of doors and hatch covers when water with a head of 2.0 m is flowing through the opening, and at an inclination of 17° in any direction. In addition watertight integrity shall comply with the details DNVGL-OS-C301 Ch.2 Sec.2 as given in the table below. Table 4 Description Reference in DNVGL-OS-C301 Ch.2 Sec.2 Internal openings [3.2] External Opening [3.3] Strength of watertight doors and hatch covers [3.4] Frame and bulkhead interface [3.5] Operation and control of watertight doors and hatch covers [3.6] 3.4 Weathertight closing appliances The closing appliances shall in general have a strength at least corresponding to the required strength of the part of the hull in which they are fitted. For side scuttles and windows, however, the pressure head shall not be taken less than 2.5 m water column. Guidance note: Some requirements are also governed by the regulations in the «International Convention of Load Lines 1966»: — doors in reg.12 — definition of positions in reg.13 — hatchways in reg.14 to reg.16 — machinery space openings in reg.17 — miscellaneous openings in reg.18 — ventilators in reg.19 — air pipes in reg.20 — scuppers, inlets and discharges in reg.22 — side scuttles in reg.23 — freeing ports in reg.24 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 37 Chapter 4 Section 2 3.2 Materials special requirements in reg.25 to reg.27. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Requirements for specific closing appliances is given in DNVGL-OS-C301 Ch.2 Sec.1 and 2 as listed in the table below. Table 5 Description Reference in DNVGL-OS-C301 Ch.2 Chain Lockers Sec.1 [5.8] Weathertight doors Sec.2 [4.2] Weathertight hatch coamings and covers Sec.2 [4.3] Gaskets and closing devices Sec.2 [4.4] Drainage arrangement Sec.2 [4.5] Buckling check Sec.2 [4.6] 3.5 Freeboard Load lines for self-elevating units are calculated under the terms of the ILLC 1966. When floating or when in transit from one operational area to another, the units shall be subject to all the conditions of assignment of the ILLC 1966 unless specifically accepted. The regulations of relevant national authorities shall also be observed. Draught marks shall be located in positions, which will ensure accurate determination of draughts, trim and heel and where they are clearly visible to personnel operating the unit or installation. The reference line shall be defined in the stability manual. Self-elevating units or installations shall not be subject to the terms of the ILLC 1966 while they are supported by the seabed or are in the process of lowering or raising their legs. The minimum freeboard of units or installations, which cannot be computed by the normal methods laid down by the ILLC 1966, shall be determined on the basis of meeting the applicable intact stability, damage stability and structural requirements for transit and operational conditions while afloat. The freeboard shall not be less than that calculated in accordance with the ILLC 1966, where applicable. Self –elevating units may be manned when under tow. In such cases a unit is subject to the bow height requirement as given in Regulation 39 (1) of the International Convention on Load Line. The requirement may not always be possible to achieve. With reference to MODU Code 3.7.18 the owner should apply to the flag administration for an exemption from the bow height requirement, having regard to the occasional nature of such voyages on predetermined routes and to prevailing weather conditions.” 3.6 Penetrations Side scuttles below freeboard deck shall be of the non-opening type with inside hinged deadlight. Other relevant requirements on penetrations are given in DNVGL-OS-C301 Ch.2 Sec.2 as given in the table below. Table 6 Description Reference in DNVGL-OS-C301 Ch.2 Sec.2 Ventilators and Air Pipes [6] Inlets, Discharges and Scuppers [7] Side Scuttles and Windows [8] Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 38 Chapter 4 Section 2 — Chapter 4 Section 3 SECTION 3 TOWING 1 General 1.1 Introduction This section provides requirements for towing. The table below lists references required for a complete understanding of this chapter. Table 1 Overview of applicable standards Reference Title DNVGL-OS-C101 Design of offshore steel structures, general DNVGL-OS-E301 Position mooring DNVGL-OS-E304 Offshore mooring steel wire ropes DNV-RP-C205 Environmental conditions and environmental loads 1.2 Plans and data to be submitted A general overview of the content of the plans and analyses is listed in Table 2. A more detailed overview, tuned to the specific design and project scope can be obtained from DNV GL’s Nauticus Production System. Table 2 Documentation requirements Object Documentation type Additional description Info Passive towing equipment supporting structures H050 – Structural drawing including towing force design loads and winch load footprint. Applicable if static force > 50 kN or bending moment > 100 kNm. AP H080 – Design analyses Applicable if static force > 50 kN or bending moment > 100 kNm FI For general requirements to documentation, including definition of the Info codes, see DNVGL-CG-0168 Sec.1. For a full definition of the documentation types, see DNVGL-CG-0168 Sec.2. 1.3 Principles Self-elevating units shall have arrangement and devices for towing. Requirements for towing systems are given in DNVGL-OS-E301 Ch.2 Sec.4[16] and Ch.3 Sec.2[11]. Requirements for equipment are given in DNVGL-OS-E304. Non-self propelled self-elevating units are not required to have temporary mooring. 2 Detailed requirements 2.1 General The unit shall have a permanent arrangement for towing. The line between the fastening devices and the fairlead shall be unobstructed. There shall be arrangements for hang-off and retrieval of the unit's towing bridle(s) and towing pennant(s). In addition to the permanent towing arrangement, there shall be a possibility of using an emergency arrangement of equivalent strength. Application of the unit's mooring arrangement may be considered for this purpose. The design load for the towing arrangement shall be clearly stated, e.g. for classed units, in the appendix to the classification certificate. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 39 Plate materials in towline fastening devices and their supporting structures shall be as given in Table 3-3 in DNVGL-OS-C101 Ch.2 Sec.3, or DNVGL-OS-C102 Ch.2 Sec.3. The termination of towing bridle(s) and/or pennant(s) where connected to the unit should be chain cable of sufficient length to ensure that steel wire rope segments of the towing arrangement will not be subject to chafing against the unit for towline pull sector between 90° port and 90° starboard. Alternatively the full length of bridle(s) and pennant(s) can be chain cable. Chain cables and shackles to be used in the towing arrangement shall be of offshore quality (R3, R3S, R4, R4S or R5) or ship chain quality K3. Green pin type shackles of polar type may be accepted provided they are certified by DNV GL. Towing bridles and pennants of steel wire rope shall be in accordance with the requirements given in DNVGL-OS-E301 respectively DNVGL-OS–E304. All eyes in towing arrangement connections shall be fitted with hard thimbles or spelter sockets in accordance with DNVGL-OS-E301 Ch.2 Sec.4 [14]. 2.3 Strength analysis The design load for the towing arrangement shall be based on the force, FT, required for towing the unit when floating in its normal transit condition. For the purpose of determining the required towing force, thrust provided by the unit's own propulsion machinery should normally not be taken into account. The unit under tow shall be able to maintain position against a specified sea state, wind and current velocity acting simultaneously, without the static force in the towing arrangement exceeding its towing design load. As a minimum the following weather conditions shall be used for calculation of environmental drift forces, FT, for world-wide towing: — sustained wind velocity: U1 min, 10 = 20 m/s (10 m above sea level) — current velocity: VC = 1 m/s — significant wave height: HS = 5 m — zero up-crossing wave period in second: 6 ≤ Tz ≤ 9. Guidance note: Environmental forces may be calculated according to DNV-RP-C205. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Normally the towing arrangement shall be designed for use of a single tug of sufficient capacity. If the size of the unit necessitates the use of two or more tugs pulling in the same direction, the towing design load, FD, to be used in the strength analysis for each towing bridle or pennant is a function of the required towing force and the number of tugs comprised in the design and given by: FD ftow = = = = ftowFT (kN) Design load factor 1.0, if NTUG = 1 1.5/NTUG, if NTUG > 1 NTUG = number of tugs comprised in the design of the towing arrangement. Guidance note: It is advised that the towing design load for each towing bridle or pennant not to be taken less than 1000 kN and that the towing arrangement is designed for use of a single tug. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- The minimum breaking strength, Smbs of the unit's towing bridle(s) and/or towing pennant(s), shall not be less than 3 times the towing design load, FD. The nominal equivalent stress, σ e in the flounder plate is normally not to exceed σ f when subjected to a load equal to the breaking strength of the unit's towline, Smbs. The strength analysis shall be made for the most unfavourable direction of the towline. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 40 Chapter 4 Section 3 2.2 Material Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 41 Chapter 4 Section 3 Towing fastening devices, including fairleads, and their supporting structures shall be designed for a load equal to the minimum breaking strength of the weakest link in the unit's towing bridle and/or towing pennants, Smbs. Strength analyses shall be made for the most unfavourable direction of the towline pull, i.e. angle of attack to device or structure. The nominal equivalent stress, σ e, in the towing devices and their supporting structures shall not exceed 0.9 σ f and 0.8 σ f, respectively. SECTION 1 MARINE, MACHINERY AND PIPING SYSTEMS 1 General 1.1 Introduction This section provides principles, technical requirements and guidance for design, manufacturing and installation of marine and machinery systems. The table below lists references required for a complete understanding of this chapter. Table 1 Overview of applicable standards Reference Title IMO Res. A.753(18) Guidelines for the application of plastic pipes on ships DNVGL-OS-B101 Metallic materials DNVGL-OS-D101 Marine and machinery systems and equipment DNVGL-OS-D202 Electrical installations DNV Rules for ships Pt.4 Ch.3 Rotating Machinery, Drivers DNV Rules for ships Pt.4 Ch.4 Rotating Machinery, Power Transmission DNV Classification Note 41.2 Calculation of Gear Rating for Marine Transmission 1.2 Application These rules apply to marine piping systems, machinery piping systems and marine machinery systems. They do not include systems primarily intended for operation in drilling or hydrocarbon production service and their dedicated auxiliary systems. Interfaces between such systems and marine systems should be identified and a specification break defined. Guidance note: Piping and equipment for drilling and drilling related auxiliary systems are addressed in DNVGL-OS-E101. These are only part of class scope if the additional class notation DRILL has been included in the contractual agreement between yard and DNV GL. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 1.3 Plans and data to be submitted Plans showing machinery arrangement shall be submitted for information. These shall show layout of machinery components such as engines, boilers, fans, heat exchangers, generators, switchboards, pumps, purifiers, filters etc., but excluding pipes, valves and accessories. The plans shall be accompanied by a list of the components and specification of make and type. A general overview of the required plans and analyses is listed in Table 2. A more detailed overview, tuned to the specific design and project scope can be obtained from DNV GL’s Nauticus Production System. Documentation shall be submitted as required by Table 2. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 42 Chapter 5 Section 1 CHAPTER 5 MACHINERY SYSTEMS AND EQUIPMENT Object Main generator diesel engine (Main/Emergency) Documentation type Additional description C040 – Design Analysis Axial vibration calculations AP C040 – Design Analysis Torsional vibration calculations for transient conditions AP C040 – Design Analysis Torsional vibration calculations for steady state conditions. Applicable for engine rated power > = 500 kW AP C040 – Design Analysis Engine vibration calculations. Applicable for engine rated power > = 200 kW. Applicable for resilient mounted engine, except generator driver set rigidly mounted on a resilient mounted frame AP C040 – Design Analysis Calculations of the static and dynamic position within the elastic mounts including type designation and fastening arrangement drawing AP S050 – Connections to the shell and to sea chests Sea valves AP Remote control of valves AP Main generator diesel engine → Resilient engine mount Machinery and marine piping systems general Valve control hydraulic power S040 – Control diagram system Info Auxiliary feed water system AP Auxiliary steam piping system (Hot Water) AP Auxiliary condensate system AP Fuel oil system AP Lubrication oil system AP Quick closing valve arrangement AP Fresh water system Compressed air systems Internal drain arrangements Cooling system AP AP S011 – Piping diagram AP Scuppers AP Sounding systems AP Overflow system AP Exhaust systems If outlets are through ships side or stern Provisions refrigeration system AP AP Sludge handling arrangement Bilge handling systems S011 – Piping diagram AP S030 – Capacity analysis AP Sea water system Ballast system S011 – Piping diagram Sea chests Z170 – Installation manual Plastic pipes only AP S050 – Connections to the shell and to sea chests Sea valves AP S011 – Piping diagram Air pipes S020 – Pressure drop analysis AP Back pressure in tanks when overfilling Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS AP Page 43 Chapter 5 Section 1 Table 2 Documentation requirements Object Documentation type Additional description I020 – Control and monitoring system documentation Control of valves and pumps Info Fuel oil control and monitoring system Lubrication oil control and monitoring system Sea water control and monitoring system Fresh water control and monitoring system Starting air control and monitoring system AP Control air control and monitoring system Bilge water control and monitoring system Ballasting control and monitoring system For general requirements to documentation, including definition of the Info codes, see DNVGL-CG-0168 Sec.1. For a full definition of the documentation types, see DNVGL-CG-0168 Sec.2. For pipes conveying steam with a temperature exceeding 400°C, the plans shall show particulars of flanges and bolts and details of welded joints with specification of welding procedure and filler metals. For calculations of thermal expansion stresses see DNVGL-OS-D101 Ch.2 Sec.2 [3.5]. Detailed information on the installation procedures for plastic pipes shall be submitted for approval. The documentation shall include information on joining procedure, supporting, clamping and expansion elements. 2 Principles 2.1 General The machinery shall be so arranged that inadvertent operation leading to reduced safety of the unit or installation or personnel, cannot occur as a consequence of one single operational error. The machinery and piping systems shall be arranged to prevent sea water, stored hydrocarbons or chemicals or ballast from reaching dry spaces of the installation or stored hydrocarbons or chemicals from being discharged overboard as a consequence of inadvertent operations. Measures shall also be taken to prevent inadvertent movement of ballast or stored fluids internally within these systems. Systems and tanks shall be so arranged that leakage or operation of valves will not directly lead to increased risk of damage to machinery, installation or personnel due to mixing of different fluids. Machinery, boilers and associated piping systems shall be so installed and protected as to reduce to a minimum any danger to persons onboard, due regard being paid to moving parts, hot surfaces and other hazards. Units or installations with ballast water treatment systems installed in order to meet the requirements of the Ballast Water Management Convention shall follow the requirements of DNV Rules for ships Pt.6 Ch.18 Sec.4. 2.2 Component design Where no specific requirements are given in these standards regarding dimensioning and choice of materials, generally recognized standards and engineering principles may be applied. If acceptable accuracy cannot be obtained by strength calculations, special tests for the determination of the strength of the design may be required. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 44 Chapter 5 Section 1 Table 2 Documentation requirements (Continued) Materials with low heat resistance shall not be used in components where fire may cause outflow of flammable or health hazardous fluids, flooding of any watertight compartment or destruction of watertight integrity. Guidance note: Materials with high heat resistance are materials having a melting point greater than 925°C. Materials with low heat resistance are all other materials. Deviations from the above requirement will be subject to special considerations. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 3 Valves 3.1 Design and tests Requirements regarding the design of valves are given in DNVGL-OS-D101, Ch.2 Sec.2 [5.1]. Required hydrostatic tests are described in [5.2]. 3.2 Installation Requirements regarding the installation of valves are given in DNVGL-OS-D101, Ch.2 Sec.1 [1.8]. 3.3 Operation Open or closed position of valves shall be easily visible. If a valve's function in the system is not evident, there shall be adequate information on a name plate attached to the valve. Other requirements regarding the operation of valves are given in DNVGL-OS-D101, Ch.2 Sec.1 [1.7]. 4 Piping 4.1 Design Marine piping systems include the following: — ballast system — bilge system — drains system — air/overflow systems — sounding system — cooling system — lubricating oil system — fuel oil system — thermal oil system — feed water and condensate systems — steam system — hydraulic system — pneumatic system — firewater system. Piping systems used for safe operation of the unit or installation shall in general be separate from piping systems used for drilling or production operations. If cross connections are necessary, appropriate means shall be fitted to prevent possible contamination of the safe system from any hazardous medium. Installation of pipes for water, steam or oil behind or above electric switchboards shall be avoided as far as possible. If this is impracticable, all detachable pipe joints and valves shall be at a safe distance from the switchboard or well shielded from it. Routing of water pipes and air and sounding pipes through freezing chambers shall be avoided. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 45 Chapter 5 Section 1 When it is of essential significance for the safety of the unit or installation that the function of a component is maintained as long as possible in the event of fire, materials with high heat resistance shall be used. 4.2 Materials Materials used in piping systems shall be suitable for the medium and service for which the system is intended. The following aspects should be considered when selecting materials: — type of service — compatibility with other materials in the system such as valve bodies and casings, for example in order to minimize bimetallic corrosion — ability to resist general and localized corrosion or erosion caused by internal fluids and/or marine environment — ability to resist selective corrosion, for example de-zincification of brass, de-aluminification of aluminium brass and graphitization of cast iron — ductility — need for special welding procedures — need for special inspection, tests, or quality control. Guidance note: The traditional stainless steels, including type 316 or 316L, are generally not considered suitable for use in seawater systems. However, certain stainless steels with higher contents of chromium, molybdenum and nitrogen have improved resistance to localised corrosion. These include high molybdenum austenitic steels and ferritic-austenitic (duplex) steels. Even these steels cannot be considered immune to attack under all situations; avoidance of stagnant seawater conditions and removal of welding oxides are some of the important factors to the successful use ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Materials to be used in the construction of piping systems shall be manufactured and tested in accordance with DNVGL-OS-B101. Carbon steel materials are in general suitable for the majority of the piping systems. Galvanised pipes are recommended as the minimum protection against corrosion for pipes in seawater systems, including those for bilge, air vent and ballast service. Non-ferrous metallic materials may be accepted in piping system transporting flammable fluids and in bilge piping provided that fire endurance properties in accordance with a recognised code is documented. In addition to the above, additional details are given in DNVGL-OS-D101 Ch.2 Sec.2 as listed in the table below. Table 3 Description Carbon and low alloy steel Reference in DNVGL-OS-D101 Ch.2 Sec.2 [2.2] Copper and copper alloys [2.3] Cast iron [2.4] Plastic pipes [2.5] Flanges, valve bodies, etc. [2.6] Bolts and nuts [2.7] Material certificates [2.8] 4.3 Platform piping 4.3.1 Pre-load/ballast The rig shall be supplied with a ballast/pre-load system with redundant pumping capability. Dump valves are accepted for drainage of the pre-load tanks. In addition, the general requirements of DNVGL-OS-D101 Ch.2 Sec.3 as listed in Table 4 shall be complied with. 4.3.2 Bilge and drainage The unit or installation shall be equipped with 100% redundancy in bilge pumping system and means for draining engine room, all compartments and watertight sections. Compartments containing liquids such as Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 46 Chapter 5 Section 1 For water-cooled electrical equipment seawater pipes shall be routed away from the equipment, so that any leakage in flanges do not damage the equipment. Again, the general requirement in DNVGL-OS-D101 Ch.2 Sec.3 as listed in Table 4 shall be complied with. Table 4 Description Reference in DNVGL-OS-D101 Ch.2 Sec.3 Basic requirements [2.1] Ballast systems [2.2] Drainage of dry compartments below main deck [2.3] Drainage of dry compartments above main deck [2.4] Pumping and piping arrangement [2.5] Bilge pipes [2.6] Bilge pumps [2.7] Bilge wells, mud boxes, valves etc. [2.8] 4.3.3 Raw water systems If the raw water system supplies water to essential systems, such as fire water systems or cooling water, system and installation requirements shall be as required for the essential system. The following raw water system requirement applies: 1) A suitable isolation valve/valves to be provided to be able to isolate one of raw water pump systems 2) In case of leg well suction, hoses may be permitted provided they are adequately supported. Hoses to be fire protected according IMO Res. A.753(18) L3 and protected from relevant fire scenarios1) except when a single incident will not impair the required raw water capacity. 3) Suction points (if both is fitted on one leg) to be at different heights (or caissons to be adequately protected). Guidance note: Submersible raw water pumps installed on a hose reel may be considered case to case. The hose reel to be located to ensure that a single incident would not damage both. Collapsible type hoses are not considered acceptable. The fire resistance of hoses as for leg well suction. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 4.3.4 Drag chains Hoses in drag chain shall be fire protected according IMO Res. A.753(18) L3 and protected from relevant fire scenarios1). 1) Reference is made to USCG PFM 1-98: Policy File Memorandum on the Fire Performance Requirements for Plastic Pipe per IMO Resolution A.753(18). 4.3.5 Air, overflow and sounding Air, overflow and sounding shall be installed according DNVGL-OS-D101 Ch.2 Sec.3 [6] as detailed below. Table 5 Description Reference in DNVGL-OS-D101 Ch.2 Sec.3 Arrangement of air pipes [6.1] Air pipes, sectional area [6.2] Overflow pipes, arrangement [6.3] Overflow pipes, sectional area [6.4] Sounding arrangements [6.5] Sounding pipes, sectional area [6.6] 4.3.6 Storage and transfer systems for helicopter fuels If installed, tanks and pipe systems for the storage and transfer systems for helicopter fuels have to comply to DNVGL-OS-D101 Ch.2 Sec.3 [7]. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 47 Chapter 5 Section 1 cooling water, oil fuel or stored produced liquid shall have their own separate pumping system. 4.4.1 General Redundancy capacity of components shall be as specified in the requirements for the different systems. Applied to piping systems this implies that more than one pump unit shall be installed when failure of such a unit will result in loss of a main function. The capacity shall normally be sufficient to cover demands at maximum continuous load on the main function when any pump unit is out of service. 4.4.2 Cooling system Cooling systems in self-elevating units or installations shall be so arranged that the supply of cooling water to the generator prime movers will not be affected during raising and lowering of the installation, even if the fire pumps are in operation. In such events the cooling water may be supplied from a storage tank. More detailed requirements are given in DNVGL-OS-D101 Ch.2 Sec.4 [2]. 4.4.3 Lubrication oil system Lubricating oil systems shall be separated from other systems. This requirement does not apply to hydraulic governing and maneuvering systems for auxiliary engines. Other requirements are given in DNVGL-OS-D101 Ch.2 Sec.4 [3] as detailed below. Table 6 Description Reference in DNVGL-OS-D101 Ch.2 Sec.4 Lubricating oil pre-treatment arrangement [3.2] Lubricating oil supply [3.3] Remote shut-off arrangement for lubricating oil tanks [3.4] 4.4.4 Fuel oil system Requirements for the fuel oil system are given in DNVGL-OS-D101, Ch.2 Sec.4 [4], as detailed in the table below. Table 7 Description Reference in DNVGL-OS-D101 Ch.2 Sec.4 Flash point of fuel oil [4.1] Fuel oil tanks [4.2] Fuel oil piping [4.3] Arrangement of valves and fittings [4.4] Remotely controlled shut-off arrangement for fuel oil tanks [4.5] Fuel oil pre-heaters [4.6] Fuel oil pre-treatment arrangement [4.7] Drip trays [4.8] Oil filters [4.9] Various requirements [4.10] 4.4.5 Feed water and condensation systems Requirements for the feed water and condensation system are given in DNVGL-OS-D101, Ch.2 Sec.4 [6], as detailed in the table below. Table 8 Description Reference in DNVGL-OS-D101 Ch.2 Sec.4 Feed water pumps and piping [6.1] Feed water heating [6.2] Feed water tanks [6.3] Condensate from steam heating of tanks [6.4] Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 48 Chapter 5 Section 1 4.4 Machinery piping The redundancy requirement of the top of the section applies to pumps, filters and pressure reduction units. Other requirements are given in DNVGL-OS-D101 Ch.2 Sec.4 [8], as detailed in the table below. Table 9 Description General Reference in DNVGL-OS-D101 Ch.2 Sec.4 [8.1] Hydraulic power supply [8.2] Hydraulic cylinders [8.3] Accumulators [8.4] Hydraulic equipment [8.5] 4.4.7 Pneumatic power supply The redundancy requirement on the top of this section applies for compressors, filters, pressure reduction units when supplying power for control of main functions, and air treatment units (lubricator or oil mist injector and dehumidifier. Other requirements on the power supply and the pneumatic equipment are given in DNVGL-OS-D101 Ch.2 Sec.4 [9]. 4.5 Pipe fabrication, workmanship and testing Fabrication, workmanship and testing of piping is described in DNVGL-OS-D101 Ch.2 Sec.6, as detailed in the table below. Table 10 Description Reference in DNVGL-OS-D101 Ch.2 Sec.6 Welding [2] Brazing of Copper and Copper Alloys [3] Pipe Bending [4] Joining of Plastic Pipes [5] Hydrostatic Tests of Piping [6] Functional Testing [7] 5 Rotating machines 5.1 Principles The machinery shall be so designed, installed and protected that risks of fire, explosions, accidental pollution, leakages and accidents thereof are acceptably low. Reliability and availability of the machinery shall be adapted according to considerations of the consequences from machinery failures and disturbances. The design arrangement of machinery foundations, shaft connections, piping and ducting shall take into account the effects of thermal expansion, vibrations, misalignment and hull interaction to ensure operation within safe limits. Bolts and nuts exposed to dynamic forces and vibrations shall be properly secured. It should be ensured that the design of the bearings and the arrangements for lubrication are satisfactory to withstand the inclinations specified in Ch.2 Sec.3 [3.6]. The manufacturer should be informed when the machine is ordered. 5.2 Diesel engines Requirements for diesel engines used for main and emergency power, including the related procedural requirements for certification and testing are described in DNV Rules for ships Pt.4 Ch.3 Sec.1 as detailed Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 49 Chapter 5 Section 1 4.4.6 Hydraulic systems Table 11 Description Reference in DNV Rules for ships Pt.4 Ch.3 Sec.1 General A Design B Testing and Inspection C Workshop Testing D Control and Monitoring E Arrangement F Vibration G Installation Inspections H Shipboard Testing I 5.3 Starting arrangements 5.3.1 Capacity Starting systems for internal combustion engines (excluding emergency generators) shall have capacity for 3 starts each. The duration of each starting shall be minimum 10 s. If a starting system serves two or more engines, the capacity of the system shall be the sum of the capacity requirements. Additional requirements to the starting system for generator sets arranged as standby generators and/or arranged for starting in a black-out situation are given in Sec.2 [1]. Requirements to starting of emergency generators are given in [5.3.4]. Drivers for fire pumps required to be fed from emergency generator shall follow the same starting requirements as for emergency generators. 5.3.2 Pneumatic Compressors shall be installed with total capacity sufficient for charging air receivers of capacities specified above from atmospheric to full pressure in the course of one (1) hour. Two or more compressors of total capacity as specified above shall be installed. The capacity shall be approximately equally shared between the compressors. At least one of the compressors shall be independently (not direct connected to the engine) driven. Engines started by compressed air shall have at least two independent starting air receivers of about equal capacity. In order to protect starting air mains against explosion arising from improper functioning of starting valve, the following devices shall be fitted: — an isolation non-return valve or equivalent at the starting air supply connection to each engine — a bursting disc or flame arrester in way of the starting valve of each cylinder for direct reversing engines having a main starting manifold — at the supply inlet to the starting air manifold for non-reversing engines. The bursting discs or flame arresters may be omitted for engines having a bore not exceeding 230 mm. The pipes and valves, including the non-return valve, shall be designed to withstand the possible back pressure if a starting valve remains open. Use of flexible hoses in the starting air system is only permitted where necessary in order to allow for relative movements. Flexible hoses with their couplings shall be type approved. 5.3.3 Electric When electric starting arrangement for auxiliary engines is used, there shall be at least two separately installed batteries, connected by separate electric circuits arranged such that parallel connection is not possible. Each battery shall be capable of starting the engine when in cold and ready to start condition. Starting arrangements for two or more main engines shall be divided between the two batteries and connected by separate circuits. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 50 Chapter 5 Section 1 in the table below. The capacity of starting batteries shall comply with capacity requirements as given on the beginning of this section. If the starting batteries are also used for supplying other consumers, the capacity shall be increased accordingly. 5.3.4 Emergency generators Emergency generating set shall be equipped with starting device with a stored energy capability of at least three consecutive starts. A second source of energy shall be provided for an additional three starts within 30 minutes, unless manual starting can be demonstrated to be effective within this time. If the emergency generator is arranged for pneumatic starting, the air supply shall be from a separate air receiver. The air receiver shall not be connected to other pneumatic systems, except for the starting system in the engine room. If such a connection is arranged, the pipeline shall be provided with a screw-down non-return valve. 5.4 Start from “dead ship” «Dead ship» condition as defined in the MODU Code Ch.1.3.15 implies for non-self propelled Self Elevating units that main power supply is out of operation and that auxiliary services (such as compressed air, starting current from batteries etc.) for the restoration of the main power supply are not available. From the above condition, the main power supply shall be brought back in operation within 30 minutes using only the facilities available on board. In addition, it shall be possible to recover from a dead ship condition with any one generator, transformer or power converter out of service. The emergency source of electrical power may be used for the purpose of starting from a dead ship condition if its capability either alone or combined with that of any other source of electrical power is sufficient to provide at the same time those services required to be supplied from the emergency power, except fire pumps. (see MODU Code 7.9.1.2, for a list of the services see DNVGL-OS-D201 Ch.2 Sec.2 [3.1.3]. 6 Jacking system 6.1 General 6.1.1 Application The requirements in this section are specific for installations of the pinion rack type. This section focuses on the requirements as relevant for the yard. The requirements relevant for the jacking gear vendor are detailed in OS-D101, Ch.2 Sec.5 [3]. The jackhouse frame, fixation system and the welding connection between rack and leg structure are dealt with in DNVGL-OS-C104 Ch.2 Sec.4 [2] and DNVGL-OS-C201 Ch.2 Sec.11 [7] and is further discussed in Sec.1 of these rules. 6.1.2 Document and plans to be submitted In general detailed information to assess the quality of the jacking gear system is supplied by its vendor. A list of the expected information is given in DNVGL-OS-D101 Ch.3 Sec.1 [4]. The yard shall specify a relevant load-time spectrum. This shall include at least the following: — raising of the legs — lowering of the legs — raising of the platform — lowering of the platform — exceptional use (e.g. one or more units out of service) — pre-load holding (static) — pre-load raising (if permitted) Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 51 Chapter 5 Section 1 The batteries shall be installed in separate boxes or lockers or in a common battery room with separate shelves (not above each other). — storm holding (static) — motor stalling torque. The elements in the load-time spectrum listed above (except motor stalling torque) are vertical net loads on the rack. The following shall be included in the load spectrum: — friction losses from leg guiding in the hull structure — effect of variation in location of the centre of gravity of the unit or installation. Unless otherwise documented, the guide friction may be taken as 10% of the net vertical force in normal operation. When lifting in a tilted position (due to soil penetration in pre-load) higher guide friction shall be assumed. When evaluating the stresses in the jacking machinery, the influence of friction in bearings and on gear flanks shall be considered. An failure mode and effect analysis (FMEA) according to DNVGL-OS-D202 Ch.3 Sec.1 Table 1-4 shall be carried out. 6.2 Design principles All jacking machinery components shall be designed for any relevant load condition mentioned above. Design safety factors etc. are valid for all foreseen operating conditions. For loads that are not foreseen, but may occur, such as motor stalling torque, lower safety factors may apply. When a design is documented by means of tests in lieu of calculations, or by combinations thereof, lower safety factors than those required by calculations may be accepted. The level will be considered on the basis of the extent of the testing and the acceptance criteria for the various parts after the test. When units or parts of units are tested, normally the whole load spectrum shall be applied and each load level shall be multiplied with the required safety factor. When different safety factors apply, such as for tooth root strength and flank durability, the highest (i.e. tooth root strength) shall be used for testing purposes. (Due to the elevated loads, some flank deterioration is considered acceptable in this case). Jacking mechanisms shall be arranged so that a single failure of any component does not cause and uncontrolled descent of the unit (ref. MODU Code 4.14.1). If the system does not include a fixation system, the pinion, gearbox and motor shaft shall be considered as structural components. Design shall hence be in line with principles in standards referenced under [6.1.1]. 6.3 Materials General requirements are given in Ch.4 Sec.1 [7.2]. Materials in forged and cast components shall satisfy the requirements given in DNVGL-OS-B101, Ch.2 Sec.3 Table B2 and Sec.4 Table B2. For materials with yield strength value higher than given in the table, the material properties are equal to the highest tabulated values. Materials in fixation chocks in the fixation system (if installed) shall be equivalent to the material in the racks. 6.4 Arrangement The jacking units shall be arranged so that they can be removed individually for servicing. The jacking system shall be arranged in such a way that visual monitoring during jacking is possible, this includes the fixation system. In case of single failures, the jacking systems shall be designed such that repair (incl. minor replacements) is possible within 3 hours. The jacking units shall be supported in such a way that elastic jack-house frame deflections are not harmful to the pinion- rack mesh. The jacking machinery with control system is defined as an important system as defined in DNVGL-OS-D202 Ch.1 Sec.1 [3.2.10]. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 52 Chapter 5 Section 1 — pre-load lowering Flexible (sandwich) rubber pads shall be protected by an oil based coating. The jack-house frame and leg-rack shall have dimensional tolerances that permits an involute gear mesh (i.e. contact ratio is above unity) between pinion and rack under all operating conditions. 6.5 Electrical systems Principles, technical requirements and guidance for design, manufacturing and installation of electrical installations, shall be in accordance to Sec.2 and be classified as an important system. Power supply shall be arranged so that no single failure prevents the jacking operation. 6.6 Control and monitoring The control and monitoring system shall be in accordance with R3 requirements described in DNVGL-OSD202, and be classified as an important system. General requirements in DNVGL-OS-D202 will apply. In case of failure in the control system, jacking operations shall be stopped or fail to a safe position. Emergency stop of jacking operation shall be possible from the vicinity of the central jacking control station. Emergency stop circuit shall be independent of the control system and failure in the circuit shall be alarmed. The jacking system should be operable from a central jacking control station. (ref. MODU code 4.14.2). A communication system should be provided between the central jacking control and a location at each leg. (ref. MODU code 4.14.4). The jacking system shall include the following control and monitoring arrangements, when applicable: — Remote indication and alarm if a brake is not released when power applied to the motors. The brake alarm shall be given by an independent mechanical sensor. — Remote indication and alarm for overheating of an electric motor. — A permanent remote indication of loads during jacking and retrieval shall be provided. For a lattice leg unit the load per chord is as a minimum to be presented. Alarm signal to be given when maximum load is exceeded. — Audible and visible alarm to indicate out-of-level. — Audible and visible alarm to indicate rack phase differential. — Indication of inclination. — Indication of power consumption. — Indication of hydraulic/pneumatic pressure. — Indication of position of pin and yoke. (this includes requirements in MODU code 4.14.3). 6.7 Testing and inspection 6.7.1 General The testing of the jacking gear system shall in general consist of workshop testing, inspection after installation and testing on board. 6.7.2 Workshop testing Spin test and contact pattern test shall be carried out according to the DNV Rules for ships Pt.4 Ch.4. Sec.2 D. 6.7.3 Installation inspection The alignment between the pinions and rack shall be checked both longitudinally and with regard to distance between pinion centre and rack. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 53 Chapter 5 Section 1 Chock pad properties shall be documented. Extent of additional documentation to be determined by FMEA and novelty of design. Possibilities for replacement of these flexible mountings shall be taken into account. — shaft alignment, see DNV Rules for ships Pt.4 Ch.4 Sec.1 H300 — fastening of propulsion gearboxes (stoppers and bolt tightening) — flushing, applicable if the system is opened during installation. Preferably with the foreseen gear oil. If — flushing oil is used, residual flushing oil shall be avoided. — lubrication oil shall be as specified (viscosity and FZG class) on maker’s list — pressure tests to nominal pressure (for leakage) where cooler, filters or piping is mounted onboard — tooth contact pattern 6.7.4 Testing on board The testing on board is part of the jacking trials as described in Sec.4. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 54 Chapter 5 Section 1 The gearing box shall be inspected on the following (with reference to DNV Rules for ships Pt.4 Ch.4 H): 1 General 1.1 Introduction This section provides principles, technical requirements and guidance for design, manufacturing and installation of electrical installations. The table below lists references required for a complete understanding of this chapter. Table 1 Overview of applicable standards Reference Title DNVGL-OS-D201 Electrical Installations IEC 61892 Mobile and fixed offshore units – Electrical installations 1.2 Application The requirements in this section apply to: — all electrical installations with respect to safety for personnel and fire hazard — all electrical installations serving essential or important services with respect to availability. 1.3 Plans and data to be submitted Documentation related to electrical installation system design shall be submitted as required by Table 2. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 55 Chapter 5 Section 2 SECTION 2 ELECTRICAL INSTALLATIONS Object Documentation type Additional description E010 − Overall single line diagram For AC, DC and UPS systems AP E050 − Single line diagrams/ consumer list for switchboards For AC, DC and UPS systems AP E040 − Electrical power consumption balance For AC, DC and UPS systems AP E220 − Electrical system philosophy System philosophy may not be required if the “overall single line diagram” is sufficient to give necessary understanding of the operation and relevant operation modes of the system. FI E200 − Short circuit calculations E210 − Harmonic distortion calculations Electric power E100 − Voltage drop calculations systems FI Required when more than 20% of connected load is by semiconductor assemblies, in relation to connected generating capacity. Upon request and when a motor rated above 30% of the feeding generator(s) or transformer(s) rated power is started direct on line. FI FI, R E080 − Discrimination analysis The document shall cover: generator protection main switchboard circuits (see DNVGL-OS-D201 Ch.1 Sec.1 [4.9.1]) emergency switchboard circuits (see DNVGL-OS-D201 Ch.1 Sec.1 [4.9.2]) battery and UPS systems AP Z030 − Arrangement plan Including locations of power sources, switchboards and distribution boards for main and emergency power, UPSs and batteries. Arrangement of access doors, fire divisions and high fire risk areas related to the above. FI Z071 − Failure mode and effect analysis (FMEA) Required if separate emergency source of power is omitted in accordance with DNVGL-OS-D201 Ch.2 Sec.2 [3.1.4]. Upon request for other systems. AP Z140 − Test procedure for quay and sea trial Redundancy and failure modes based on FMEA. Required if separate emergency source of power is omitted in accordance with DNVGL-OS-D201 Sec.2 [3.1.4]. Upon request for other systems. AP Motor starters E170 − Electrical schematic drawing Cables E030 − Cable selection philosophy Emergency stop system E170 − Electrical schematic drawing Installation in hazardous E090 − Table of Ex-installation areas Lighting systems Info Starters for essential services. AP Emergency stop of electrical propulsion motors, pumps and fans, showing fail to safe functionality. Based on approved area classification drawing and ESD philosophy (if relevant). E190 − Lighting description Z030 − Arrangement plan AP AP AP AP Emergency lighting arrangement AP For general requirements to documentation, including definition of the Info codes, see DNVGL-CG-0168 Sec.1. For a full definition of the documentation types, see DNVGL-CG-0168 Sec.2. For documentation requirements of electrical equipment required to be delivered with DNV GL Product Certificate see Ch.6 Sec.2 [4]. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 56 Chapter 5 Section 2 Table 2 Documentation requirements The following principles apply to electrical installations: — Electrical installations shall be such that the safety of passengers, crew and unit from electrical hazards, is ensured. — There shall be two mutually independent and self contained electric power supply systems on board: — main electric power supply system — emergency electric power supply system. Exceptions are given in DNVGL-OS-D201 Ch.2 Sec.2 [3.1.4]. — Services required for normal operation of the offshore unit shall be operable with the emergency electrical power generation and distribution system being unavailable, unless such services are permitted to be powered by emergency electrical power supply only. — All consumers that support functions required to be available in normal operation, shall be supplied from distribution systems independent of the emergency electrical power supply system. Exemptions are made for one of redundant consumers required for dead ship recovery. — All consumers required to be available in emergency operation shall be supplied from distribution systems independent of the main electric power supply system. — Consumers required having both main and emergency supply shall be supplied as required by relevant rules applicable for these consumers. The primary supply shall be from the main system. — Offshore units without a dedicated emergency electric power supply system are accepted upon compliance with requirements in DNVGL-OS-D201 Ch.2 Sec.2 [3.1.4]. Relevant specifications for system voltage, frequency and earthing are given in DNVGL-OS-D201 Ch.2 Sec.2 as follows: Table 3 Description Reference in DNVGL-OS-D201 Ch.2 Sec.2 System earthing [1.1.3] Types of distribution system [1.1.4] Hull return systems [1.1.5] System voltages and frequencies [1.2] Lightning protection [9.6] Earthing of aluminium superstructures on steel offshore units [9.7] 3 Arrangements and installation 3.1 Arrangement Arrangements for electrical installations are specified in DNVGL-OS-D202 Ch.2 Sec.2 [9] as follows: Table 4 Description Reference in DNVGL-OS-D201 Ch.2 Sec.2 Ventilation [9.1.1] Arrangement of power generation and distribution [9.1.2] Installation of switchboards1 [9.2.1] Arrangement for high voltage switchboard rooms [9.2.2] Passage ways for main and emergency switchboards [9.2.3] Distribution switchboards [9.2.4] 1 Applies for transformers as well For the arrangement of batteries see Sec.4 [4.3]. 3.2 Installation The following applies for installation of electrical equipment: — All electrical equipment shall be permanently installed and “electrically safe”. This shall prevent injury Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 57 Chapter 5 Section 2 2 Principles — All electrical equipment shall be selected and installed so as to avoid EMC problems. Thus preventing disturbing emissions from equipment, or preventing equipment from becoming disturbed and affecting its intended function(s). — Electrical equipment shall be placed in accessible locations so that those parts, which require manual operation, are easily accessible. — Heat dissipating electrical equipment as for example lighting fittings and heating elements, shall be located and installed so that high temperature equipment parts do not damage associated cables and wiring, or affect surrounding material or equipment, and thus become a fire hazard. (Interpretation of SOLAS Ch.II- 1/45.7) — Equipment shall be installed in such a manner that the circulation of air to and from the associated equipment or enclosures is not obstructed. The temperature of the cooling inlet air shall not exceed the ambient temperature for which the equipment is specified. — All equipment of smaller type (luminaries, socket outlets etc.) shall be protected against mechanical damage either by safe location or by additional protection, if not of a rugged metallic construction. In addition installation requirements are given in DNVGL-OS-D201 Ch.2 Sec.10 [2] as listed in the table below. Table 5 Description Reference in DNVGL-OS-D201, Ch.2 Sec.10 Ventilation [2.1.2] High voltage switchgear [2.1.3] Passage of switchboards [2.1.4] Transformers [2.1.5] Heating and cooking appliances [2.1.6] Equipment enclosure, ingress protection [2.2] 4 Power supply 4.1 Main 4.1.1 Capacity The main power supply system shall have the capacity to supply power to all services necessary for maintaining the offshore unit in normal operation without recourse to the emergency source of power. There shall be component redundancy for main sources of power, transformers and power converters in the main power supply system so that with any source, transformer or power converter out of operation, the power supply system shall be capable of supplying power to the following services: — those services necessary to provide normal operational conditions and safety — starting the largest essential or important electric motor on board, except auxiliary thrusters, without the transient voltage and frequency variations exceeding the limits specified in DNVGL-OS-D201 Ch.2 Sec.2 [1.2] — ensuring minimum comfortable conditions of habitability which shall include at least adequate services for cooking, heating, domestic refrigeration (except refrigerators for air conditioning), mechanical ventilation, sanitary and fresh water — for a duplicated essential or important auxiliary, one being supplied non-electrically and the other electrically (e.g. lubricating oil pump No. 1 driven by the main engine, No. 2 by electric motor), it is not expected that the electrically driven auxiliary is used when one generator is out of service For “dead ship” recovery, see Ch.5 Sec.1 [5.4]. 4.1.2 Generator prime movers Each generator shall normally be driven by a separate auxiliary engine not to be used for driven other auxiliary systems. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 58 Chapter 5 Section 2 to personnel, when the equipment is handled or touched in the normal manner. (Interpretation of SOLAS Ch.II-1/45.1.3) Guidance note: Generators based on variable speed drives will be evaluated in each case. As a minimum, the following should be evaluated: — availability — stability of output voltage and frequency — short circuit capability and protection. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 4.1.3 System functionality At least two generator sets, connected to separate main busbar sections, shall be arranged with systems for starting in a blackout situation. However, only one standby generator may be permitted if this generator is not intended to be used for normal operation of the offshore unit. Requirements to energy for starting and supply to auxiliaries required for starting are given in DNVGL-OSD201 Ch.2 Sec.2 [2.2.2]. 4.1.4 Load shedding and automatic restoration of power The system shall be so arranged that the electrical supply to ensure safety of the offshore unit, will be maintained or immediately restored in case of loss of any one of the generators in service. This means: — All generators shall be equipped with automatic load shedding or other automatic means to prevent sustained overload of any generator, see DNVGL-OS-D201 Ch.2 Sec.2 [7.1.1]. — Where the electrical power is normally supplied by one generator provision shall be made, upon loss of power, for automatic starting and connecting to the main switchboard of standby generator(s) of sufficient capacity with automatic restarting of the essential auxiliaries, in sequential operation if required. Starting and connection to the main switchboard of the standby generator shall be preferably within 30 seconds, but in any case not more than 45 seconds, after loss of power. — Where prime movers with longer starting time are used, this starting and connection time may be exceeded upon approval from the society. — Where more than one generating set is necessary to cover normal loads, the power supply system shall be provided with suitable means for tripping or load reduction of consumers. If necessary, important consumers may be tripped in order to permit propulsion and steering and to ensure safety. If the remaining on line generators are not able to permit propulsion and steering and to ensure safety, provision shall be made for automatic starting and connection to the main switchboard of the standby generator. 4.2 Emergency power supply systems Requirements for emergency power supply systems are given in DNVGL-OS-D201 Ch.2 Sec.2 [3]. Table 6 Description Reference in DNVGL-OS-D201 Ch.2 Sec.2 Emergency power source [3.1.1] Capacity [3.1.2] Services to be supplied [3.1.3] Independent installation of power sources [3.1.4] Emergency switchboard [3.1.5] Transitional source [3.2] Emergency generators [3.3] 4.3 Battery systems Trip of battery by Emergency Shutdown System (ESD) shall be arranged as required by DNVGL-OS-A101 Ch.2 Sec.4. Additional requirements for rechargeable Lead Acid and NiCd batteries are given in DNVGL-OS-D201 Ch.2 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 59 Chapter 5 Section 2 Auxiliary engines shall comply with the requirements in DNVGL-OS-D101 Sec.5 [2]. Table 7 Description Reference in DNVGL-OS-D201 Ch.2 Capacity of accumulator batteries Sec.2 [4.1.1] Battery powered systems Sec.2 [4.1.2] Battery monitoring Sec.2 [4.1.3] Arrangement Sec.2 [4.1.3] Ventilation Sec.2 [4.1.4] Charging stations for battery powered fork lift (if applicable) Sec.2 [4.1.5] Materials for installation Sec.10 [2.3.2] Testing Sec.10 [2.3.3] Requirements for installation of electrical equipment in battery rooms, lockers and boxes are given in Sec.3, alternatively DNVGL-OS-D201 Ch.2 Sec.11 [3.2.5]. Installation of rechargeable battery types other than Lead Acid and NiCd will be evaluated case-by-case based on the above requirements and DNV Rules for ships Pt.6 Ch.28 - Tentative Rules for Battery Power. Installation and ventilation recommendations from the manufacturer should always be followed. 4.4 Power supply to jacking gear For power supply to jacking gear, see Ch.5 Sec.1 [6.4]. 5 Electrical power distribution Requirements to electric power distribution are given in DNVGL-OS-D201 Ch.2 Sec.2 [6] as follows: Table 8 Description Reference in DNVGL-OS-D201 Ch.2 Sec.2 General [6.1.1] Consequence of single failure [6.1.2] Division of main busbars See below Generator circuits [6.1.4] Lighting [6.2] Power supply to control and monitoring systems [6.3] Low voltage shore connections [6.4] Due to redundancy requirement for jacking machinery, the main busbar shall be subdivided into at least two parts. So far as is practicable, the connection of generating sets and other duplicated equipment shall be equally divided between the parts. In addition: — For high voltage distribution systems, the main busbar sections shall be connected by circuit breaker. — For low voltage distribution systems, busbars which can be divided into at least two parts within three hours can be accepted. (System category “repairable system” R3 as defined in DNVGL-OS-D202 Ch.2 Sec.1 [2.1.2]. 6 Protection Requirements to protection are given in DNVGL-OS-D201 Ch.2 Sec.2 [7] as follows: Table 9 Description Reference in DNVGL-OS-D201 Ch.2 Sec.2 System protection [7.1] Circuit protection [7.2] Generator protection [7.3] Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 60 Chapter 5 Section 2 Sec.2 as follows: (Continued) Description Reference in DNVGL-OS-D201 Ch.2 Sec.2 Transformer protection [7.4] Motor protection [7.5] Battery protection [7.6] Harmonic Filter protection [7.7] 7 Control Requirements to control of electric equipment are given in DNVGL-OS-D201 Ch.2 Sec.2 [8] as follows: Table 10 Description Reference in DNVGL-OS-D201 Ch.2 Sec.2 Control circuits [8.1] Control of generator sets and main power supply [8.2] Main and emergency switchboard control [8.3] Motor control [8.4] Emergency stop [8.5] 8 Electrical equipment: In general, DNV GL’s electrical equipment requirements are based on IEC standard IEC 61892, part 1, “General requirements and conditions”, part 2 “Systems design”, and part 3 “Equipment”. For environmental requirements, see Ch.4 Sec.1 [4.2]. Other general requirements for electrical equipment are given in DNVGL-OS-D201 Ch.2 Sec.3 as listed in the table below. Table 11 Description Reference in DNVGL-OS-D201 Ch.2 Sec.3 Electrical parameters [3.1] Maximum operating temperatures [3.2] Mechanical strength [4.1] Cooling and anti-condensation [4.2] Termination and cable entrances [4.3] Equipment protective earthing [4.4] Enclosures ingress protection [4.5] Clearance and creepage distances [4.6] Insulation materials [6.1] Requirements for specific electrical equipment are given in DNVGL-OS-D201 Ch.2 as listed below. Table 12 Description Reference in DNVGL-OS-D201 Ch.2 Switchgear and control gear assemblies Sec.4 Rotating Machines Sec.5 Power transformers Sec.6 Semi-conductor converters Sec.7 Miscellaneous Equipment Sec.8 9 Cables 9.1 Cable selection These technical requirements for cables and cable installations are considered relevant for the system design phase of a project. However, they apply as well to the final installation on the offshore unit. Details Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 61 Chapter 5 Section 2 Table 9 Table 13 Description Reference in DNVGL-OS-D201 Ch.2 Sec.2 Fire resistant cables [10.1.2] Voltage rating [10.1.3] Colour code on earthing cable [10.1.4] Cable separation and protection [10.1.5] Cable temperature [10.2] Choice of insulation materials [10.3] Rating of earth conductors [10.4] Correction factors [10.5] Parallel connection of cables [10.6] Additional requirements for AC installations and special DC installations [10.7] Rating of cables [10.8] 9.2 Cable construction and rating The cables shall comply to the standards as described in DNVGL-OS-D201 Ch.2 Sec.9 as listed in the table below. Table 14 Description Reference in DNVGL-OS-D201 Ch.2 Sec.9 Application [1] General cable construction [2] High voltage cables [3] Low voltage power cables [4] Control and instrumentation cables [5] Data communication cables [6] Fibre optic cables [7] Inspection and testing [8] 9.3 Cable routing and installations Cable runs shall be installed well clear of substantial heat sources such as boilers, heated oil tanks, steam, exhaust or other heated pipes, unless it is ensured that the insulation type and current rating is adapted to the actual temperatures at such spaces. Other relevant requirements are given in DNVGL-OS-D201 Ch.2 Sec.2 and Sec.10 as detailed in the table below. Table 15 Description Reference in DNVGL-OS-D201 Ch.2 Separation of cables for emergency services, essential and important equipment Sec.2 [9.5.2] Separation of main generators or main power converters cabling Sec.2 [9.5.2] Routing of cables Sec.10 [3.2] Penetrations of bulkheads and decks Sec.10 [3.3] Fire protection measures Sec.10 [3.4] Support and fixing of cables and cable runs Sec.10 [3.5] Cable expansion Sec.10 [3.6] Cable pipes Sec.10 [3.7] Splicing of cables Sec.10 [3.8] Termination of cables Sec.10 [3.9] Trace or surface heating installation requirements Sec.10 [3.10] Additional requirements for cables installed in hazardous areas are given in DNVGL-OS-D201 Ch.2 Sec.11 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 62 Chapter 5 Section 2 can be found in DNVGL-OS-D201 Ch.2 Sec.2 [10] as detailed in the table below. Table 16 Description Reference in DNVGL-OS-D201 Ch.2 Sec.11 Cable types [4.2.1] Fixed cable installations [4.2.2] Flexible cables [4.2.3] Penetrations of bulkheads and decks [4.2.4] Cable entrance into equipment [4.2.5] Termination and wiring inside Ex-e and Ex-d enclosures [4.2.6] Intrinsically safe circuit wiring and termination [4.2.7] Special conditions in EX certificates [4.2.8] Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 63 Chapter 5 Section 2 as detailed in the table below. Chapter 5 Section 3 SECTION 3 AREA ARRANGEMENTS 1 General 1.1 Scope This chapter covers the arrangement of areas in general and hazardous areas with the relevant requirements for machinery and electrical equipment. The table below lists references required for a complete understanding of this chapter. Table 1 Overview of applicable standards Reference Title DNVGL-OS-A101 Safety principles and arrangements DNVGL-OS-C301 Stability and Watertight Integrity DNVGL-OS-D101 Marine and machinery systems and equipment DNVGL-OS-D201 Electrical installations DNVGL-OS-D202 Automation, safety, and telecommunication systems IEC 61892 Mobile and fixed offshore units – Electrical installations 1.2 Plans and data to be submitted Documentation related to this chapter shall be submitted as required by the table below. Table 2 Documentation requirements Object Hazardous area classification Documentation type Additional description Info G070 – Source of release schedule FI G080 – Hazardous area classification drawing AP Ventilation systems S012 – Ducting diagram AP Muster station/ safe area Z030 – Arrangement plan AP Escape route G120 – Escape route drawing AP For general requirements to documentation, including definition of the Info codes, see DNVGL-CG-0168 Sec.1. For a full definition of the documentation types, see DNVGL-CG-0168 Sec.2. 2 Divisions and equipment location 2.1 General The unit or installation shall be divided into different areas according to the type of activities that will be carried out and the associated hazard potential. Areas of high risk potential shall be segregated from areas of low risk potential, and from areas containing important safety functions. Incident escalation between areas shall be avoided. Accommodation and other areas important for safety, such as control stations, shall be located in areas classified as non-hazardous by location, and as far as practicable away from hazardous areas for hydrocarbon processing, hydrocarbon storage, wellheads, risers and drilling. The effect of prevailing winds and potential for segregation by less hazardous areas shall also be considered for area protection. Use of firewalls, blast walls, cofferdams etc. shall be considered in cases where segregation by physical distance is not sufficient. Where control stations or control functions are located in LER/LIRs outside the accommodation block/safe area special precautions against gas ignition related to gas detection, ventilation and shutdown will need to be provided. Specific requirements for location of equipment are given in DNVGL-OS-A101 Ch.2 as listed in the table Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 64 Table 3 Description Reference in DNVGL-OS-A101 Ch.2 Location of safety systems Sec.2 [4.1] Location of air intakes and other openings Sec.2 [4.2] Fired heaters, combustion engines and hot surfaces Sec.2 [4.3] Location of flares and vents Sec.2 [4.4] Storage of dangerous goods Sec.2 [5] Cranes and lay down areas Sec.2 [6] Asbestos and railing and barriers Sec.2 [7] Mooring, moonpool, production and well testing and control station Sec.6 [2] 2.2 Electrical installations Arrangements for electrical installations are specified in DNVGL-OS-D201 Ch.2 Sec.2 [9] as listed below. Table 4 Description Reference in DNVGL-OS-D201 Ch.2 Sec.2 Ventilation [9.1.1] Arrangement of power generation and distribution [9.1.2] Installation of switchboards [9.2.1] Arrangement for high voltage switchboard rooms [9.2.2] Passage ways for main and emergency switchboards [9.2.3] Distribution switchboards [9.2.4] 3 Hazardous areas 3.1 Area classification Hazardous areas are classified as follows: — Zone 0: in which an explosive gas atmosphere is continuously present or present for long periods. (Typical for continuous grade source present for more than 1000 hours a year or that occurs frequently for short periods). — Zone 1: in which an explosive gas atmosphere is likely to occur in normal operation. (Typical for primary grade source present between 10 and 1000 hours a year). — Zone 2: in which an explosive gas atmosphere is not likely to occur in normal operation, and if it does occur, is likely to do so infrequently and will exist for a short period only. (Typical for secondary grade source present for less than 10 hours per year and for short periods only). 3.2 Battery rooms, paint stores, and welding gas bottle stores Electrical equipment installed in battery rooms lockers or boxes, paint stores or welding gas bottle stores, and in ventilation ducts serving such spaces shall be suitable for installation in zone 1 with the following requirements for gas group and ignition temperature: — battery rooms: minimum gas group II C and temperature class T1 — paint stores: minimum gas group II B and temperature class T3 — welding gas bottle stores: minimum gas group II C and temperature class T2. Cables routed through such spaces shall either be suitable for installation in hazardous area zone 1, or be installed in metallic conduit. Areas on open deck within 1m of inlet and exhaust ventilation openings or within 3 m of exhaust outlets with mechanical ventilation are classified as zone 2. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 65 Chapter 5 Section 3 below. — the door to the space is a gastight door with self-closing devices and without holding back arrangements (a watertight door is considered gastight) — the space is provided with an acceptable, independent, natural ventilation system ventilated from a safe area — warning notices are fitted adjacent to the entrance to the space stating that the store contains flammable liquids or gas. Battery rooms and lockers or boxes shall be regarded as zone 2 hazardous areas with respect to access doors, lids or removable panels and possible interference with other rooms. The fan mounted inside extract ventilation ducts shall be of non-sparking type. 3.3 Requirements for specific systems 3.3.1 Combustion engines Combustion equipment and combustion engines shall normally not be located in hazardous areas. Where it is necessary to house combustion engines in a hazardous area, either the equipment shall be placed in a pressurized space or the equipment shall be otherwise protected to prevent ignition (see DNVGL-OS-A101 Ch.2 Sec.2 [4.3]. 3.3.2 Electrical installations and cables Electrical equipment and cables installed in hazardous areas shall be limited to that necessary for operational purposes. Electrical equipment with temperature Class T3 (maximum 200°C) shall be used when hydrocarbon gases give rise to hazardous areas. The installation in hazardous areas shall comply with DNVGL-OS-D201 Ch.2 Sec.11. Electrical cables are as far as possible to be routed outside areas containing drilling mud (see DNVGL-OSA101 Ch.2 Sec.6 [3.3]. Electrical equipment left operational after APS shutdown or as located in non-hazardous areas affected by a gas release shall be certified for operation in zone 2 areas. The certification requirement does not apply if the room where the equipment is located is efficiently isolated (typically living quarters). 4 Ventilation systems The ventilation system shall be designed to maintain acceptable working and living environment for the personnel and non-detrimental conditions for equipment and machinery. There shall be independent ventilation systems for hazardous and non-hazardous areas. Non-hazardous enclosed spaces shall be ventilated with over pressure in relation to hazardous areas. Regarding ventilation of spaces in which machinery is operated and where flammable or toxic gases or vapours may accumulate, where low oxygen atmosphere may occur, machinery spaces and emergency generator room shall be provided with adequate ventilation under all conditions. Guidance note: By adequate ventilation is meant natural or mechanical ventilation sufficient to prevent an accumulation of gases above a concentration of 25% of their Lower Explosion Limit (LEL). ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Specific requirements for specific areas are given in DNVGL-OS-A101 and DNVGL-OS-D101 as listed in the table below. Table 5 Description Reference in DNVGL-OS-A101 and DNVGL-OS–D101 Location for air intakes and other openings DNVGL-OS-A101 Ch.2 Sec.3 [4.3] Accommodation and control spaces DNVGL-OS-D101 Ch.2 Sec.4 [11.1] Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 66 Chapter 5 Section 3 Enclosed spaces giving access to such areas may be considered as non-hazardous, provided that: (Continued) Description Reference in DNVGL-OS-A101 and DNVGL-OS–D101 Ventilation of Machinery spaces DNVGL-OS-D101 Ch.2 Sec.4 [11.2] Ventilation of Gas Hazardous areas DNVGL-OS-D101 Ch.2 Sec.4 [11.3] Fans serving hazardous spaces DNVGL-OS-D101 Ch.2 Sec.4 [11.4] Ductwork DNVGL-OS-D101 Ch.2 Sec.4 [11.5] 5 Marking and signboards For the installation of marking and signboards, the overview of Table 1 can be followed. Table 6 Marking and signboards - overview TEXT of SIGNBOARD (EXAMPLE) PLACES to be DISPLAYED OS RULE REFERENCE HAZARDOUS AREA On self-closing doors between areas with different area classification DNVGL-OS-A101 Ch.2 Sec.5 [5.2.3] “ESCAPE TO SEA” Escape ways to sea DNVGL-OS-A101 Ch.2 Sec.5 [5.1.1] “SMOKING AND USE OF NAKED LIGHTS PROHIBITED” Areas for storage of flammable, radioactive, explosive or otherwise hazardous substances DNVGL-OS-A101 Ch.2 Sec.2 [5.1] “TO BE KEPT CLOSED AT SEA” Internal openings which are kept permanently closed during the operation of the unit. Locally operated doors or hatch covers. Hatch on upper deck to engine room. Rope hatches on mooring deck, forward and aft. Hatch on aft mooring deck to steering gear room. Hatch on forward mooring deck to bosun store. Hatches on main deck to fuel oil and ballast tanks. DNVGL-OS-C301 Ch.2 Sec.2 [2.2.2] DNVGL-OS-C301 Ch.2 Sec.2 Table I1 “SEA DIRECT” All connections (inlet/outlet) to sea. DNVGL-OS-D101 Ch.2 Sec.1 [1.2.6] DNVGL-OS-C301 Ch.2. Sec.2 [6.1.1] xxx On sounding pipes for tanks, cofferdams and pipe tunnels DNVGL-OS-D101 Ch.2 Sec.3 [5.5.4] DNVGL-OS-D101 Ch.2 Sec.3 [5.5.5] “MAXIMUM ALLOWABLE PUMP CAPACITY FOR TANKS WHICH CAN BE FILLED BY PUMPS NOT INSTALLED IN THE VESSEL IS (specify capacity) M3/H” On loading station pipe connection for filling of tanks which can be filled by pumps not installed in the vessel. DNVGL-OS-D101 Ch.2 Sec.3 [5.2.1] “CAUTION! NO BURNER TO BE FIRED BEFORE THE FURNACE HAS BEEN PROPERLY PURGED” Boiler control panels next to boiler and remote boiler panels. Control panel for incinerator. Control panel for inert gas generator DNVGL-OS-D101 Ch.2 Sec.3 [5.5.4] DNVGL-OS-D101 Ch.2 Sec.3 [5.5.5] Tank and space number All air pipes from tanks and spaces shall be clearly marked at the upper end with the tank or space number. DNVGL-OS-D101 Ch.2 Sec.2 [5.1.11]1 Indication open/ close If wrong operation may cause damage on switchgear for sectioning on the busbar then instructions for correct operation shall be given by signboard on the switchboard. It shall be clearly indicated whether such switchgear is open or closed. DNVGL-OS-D201 Ch.2 Sec.2 [8.2] “HIGH VOLTAGE” High voltage machines, transformers, cables, switchgear and control gear assemblies (marked every 20 meters) DNVGL-OS-D201 Ch.2 Sec.3 [5.1.4] DNVGL-OS-D201 Ch.2 Sec.10 [2.5.3] “CAUTION! (rated voltage) FUSES ONLY” Switchgear fed from more than one individually protected circuit DNVGL-OS-D201 Ch.2 Sec.3 [5.1.4] Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 67 Chapter 5 Section 3 Table 5 TEXT of SIGNBOARD (EXAMPLE) PLACES to be DISPLAYED OS RULE REFERENCE “DANGER! (maximum voltage) VAC ONLY FOR CONNECTION OF (type of equipment)” Each socket outlets for portable appliances which are not handheld during operation (i.e. welding transformers, refrigerated containers) DNVGL-OS-D201 Ch.2 Sec.8 [1.1.1] “WARNING! EXPLOSIVE GAS NO SMOKING OR USE OF NAKED LIGHTS” Battery rooms and on doors or covers of boxes or lockers DNVGL-OS-D201 Ch.2 Sec.10 [2.5.2] “WARNING! (rated voltage) VOLTAGE” Battery systems above 50V DNVGL-OS-D201 Ch.2 Sec.10 [2.5.2] “ONLY TO BE USED IN PORT” Motors on open deck shall have ingress protection DNVGL-OS-D201 Ch.2 Sec.10 Table 10-1 IP 56, and either: be naturally cooled, i.e. without external cooling fan be vertically mounted and equipped with an additional steel hat preventing ingress of water or snow into any external ventilator or be equipped with a signboard requiring that the motor shall only be used in port, and be provided with additional covers (e.g. tarpaulins) at sea. Signboards giving guidance for safe use, or conditions for use, shall be fitted, if necessary, in order to avoid inadvertent or dangerous operation of equipment and or systems DNVGL-OS-D201 Ch.2 Sec.10 [2.5.2] “ENGINE ALARM” “INERGEN” “H2S” “HC” On all visual alarms in rooms / spaces shall be marked with name of alarm. DNVGL-OS-D202 Ch.2 Sec.2 [1.5.2] Instructions for correct operation Switchboards that are arranged for supply by two DNVGL-OS-D202 Ch.2 Sec.2 (or more) alternative circuits shall be provided with [8.3.6] interlock or instructions for correct operation by signboard on the switchboard. Positive indication of which of the circuits is feeding the switchboard shall be provided. “ALARM TO BE SOUNDED PRIOR TO REMOTE OPERATION” On location(s) where remote operation of the windlasses or winches can be carried out Guidance/ conditions for safe use Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS DNVGL-OS-E301 Ch.2 Sec.4 [11.5.14] Page 68 Chapter 5 Section 3 Table 6 Marking and signboards - overview (Continued) Chapter 5 Section 4 SECTION 4 CONTROL AND COMMUNICATION SYSTEMS AND EMERGENCY SHUTDOWN 1 General 1.1 Introduction This chapter list requirements for control and telecommunication systems and Emergency shutdown. The table below lists references required for a complete understanding of this chapter. Table 1 Overview of applicable standards Reference Title IMO Res. A.830(19) Code on Alarms and Indicators, 1995 DNVGL-OS-A101 Safety principles and arrangements DNVGL-OS-D202 Automation, Safety, and Telecommunication Systems 1.2 Application The requirements in this system are in special applicable for the fire and gas system, platform automation and GA/PA system. In this respect, the suppliers of these systems should take special notice of these during their system design, delivery and installation on board. 1.3 Plans and data to be submitted A general overview of the required plans and analyses to be submitted is listed Table 2. A more detailed overview, tuned to the specific design and project scope can be obtained from DNV GL’s Nauticus Production System. Table 2 Documentation requirements Object Documentation type Vessel control and monitoring systems Z140 – Test procedure for quay and sea trial Additional description Info AP Engineer's alarm system I200 – Control and monitoring system documentation AP Integrated control and monitoring system G170 – Control system philosophy AP Emergency shut down system AP G130 – Control and monitoring system documentation For general requirements to documentation, including definition of the Info codes, see DNVGL-CG-0168 Sec.1. For a full definition of the documentation types, see DNVGL-CG-0168 Sec.2. 2 Principles 2.1 General The principles for automation, safety and telecommunication systems are described in DNVGL-OS-D202 as further outlined in the remaining of this chapter. The definitions of safety and important systems together with the different levels of system availability as given in Sec.1 [6.2] are applicable for the automation system controlling these systems as well. 2.2 Response to failures 2.2.1 Failure detection Essential and important systems shall have facilities to detect the most probable failures that may cause reduced or erroneous system performance. Failures detected shall initiate alarms in an assigned manned control station. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 69 — power failures. Additionally for computer based systems: — communication errors — hardware failures — software execution failures. Additional for essential/safety systems: — Loop failures — Earth faults. 2.2.2 Fail-safe functionality The most probable failures, for example loss of power or wire failure, shall result in the least critical of any possible new conditions. 3 System design The safety and automation system shall be designed as mutually independent systems. The different elements shall not be designed as one combined system, where safety functions are combined with automation functions. For essential and important systems, deviations between a command action and expected result of the command action shall initiate an alarm. Planning and reporting system elements shall have no outputs for real-time process equipment control during planning mode. Output from calculation, simulation or decision support modules shall not suppress basic information necessary to allow safe operation of essential and important functions. Other detailed requirements are given in DNVGL-OS-D202 Ch.2 Sec.2 as listed in the table below. Table 3 Description Reference in DNVGL-OS-D202 Ch.2 Sec.2 Automation system [1.2] Safety system [1.4] Alarms [1.6] Indications [1.7] System operation and maintenance [2.1] For computer based systems, additional requirements as given in DNVGL-OS-D202 Ch.2 Sec.3 apply as detailed in the table below. Table 4 Description References in DNVGL-OS-D202 Ch.2 Sec.3 General requirements [1] System software [2] Network systems and communication [3] 4 Component design and installation For the design of components and installed typically under responsibility from the yard, the specific Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 70 Chapter 5 Section 4 The failure detection facilities shall at least, but not limited to, cover the following failure types: Table 5 Description Reference in DNVGL-OS-D202 Ch.2 Sec.4 General [1] Environmental conditions [2] Electrical and electronic equipment [3] Pneumatic and Hydraulic equipment [4] 5 User interface The location and design of the user interface shall give consideration to the physical capabilities of the user and comply with accepted ergonomic principles. This requirement affects workstation design and arrangement, user input devices and displays/ screens. Detailed requirements are given in DNVGL-OSD202 Ch.2 Sec.5 as detailed in the table below. Table 6 Description References in D202 Ch.2 Sec.5 Workstation design and arrangement [2] User Input Device and Visual Display Unit Design [3] Screen based systems [4] 6 ESD and emergency control 6.1 Emergency shut down 6.1.1 General An emergency shutdown (ESD) shall be provided following the requirements as given in the MODU code and further clarified by DNV GL interpretations as listed below. 6.1.2 Installation In order to meet the objective of ignition control in abnormal condition, an ESD system shall be provided to facilitate the selective disconnection or shutdown of: — ventilation systems, except fans necessary for supplying combustion air to prime movers for the production of electrical power; — main generator prime movers, including the ventilation systems for these; — emergency generator prime movers. (see MODU code 6.5.1) Interpretation: All HVAC inlets without dedicated gas detection should be automatically shutdown immediately upon gas detection anywhere. Shutdown of HVAC implies trip of HVAC fan and close of relevant dampers. Individual HVAC inlets provided with dedicated gas detection should be automatically shutdown immediately upon local gas detection. Inlets for prime movers for production of electricity do not need to be individually tripped if they supply combustion air to the prime mover only. Combined HVAC- and combustion inlets do not need to be tripped if branch take-off to room ventilation can be tripped. ––––––––––––––– end of Interpretation ––––––––––––––– 6.1.3 Operation Disconnection or shutdown shall be possible from at least two strategic locations, one of which should be outside hazardous areas. (see MODU code 6.5.3) Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 71 Chapter 5 Section 4 requirements in DNVGL-OS-D202 Ch.2 Sec.4 apply as detailed in the table below. Additional automatic inputs will be accepted. Locations indicated in Table 9 should be applied as a basis. Table 7 Location of push buttons for manual shutdown Shutdown level Location of push-button Abandon vessel (AVS) — main and emergency control rooms, i.e. bridge and back-up control room — muster stations, lifeboat stations and helicopter deck — bridge connections between units/installations (if any) As for AVS, plus (where applicable): Emergency shutdown (ESD) Manually activated call point (MAC) ––––––––––––––– — process control room — driller’s control cabin — exits and main escape routes from process, drilling, wellhead, riser areas etc Readily available for use in all normally manned areas (see DNVGL-OSD301 Ch.2 Sec.4 [3]) end of Interpretation ––––––––––––––– 6.1.4 Unintentional stoppages/ inadvertent operation Shutdown systems shall be so designed that the risk of unintentional stoppages caused by malfunction in a shutdown system and the risk of inadvertent operation of a shutdown are minimized. (see MODU code 6.5.4) Interpretation: The ESD system should be designed to allow testing without interrupting other systems onboard. The ESD Operator Station/HMI unit should be located in a non-hazardous and continuously manned area. The ESD control unit, comprising operator stations/HMI units and logic solver(s), should be powered as required by DNVGL-OS-D201 Ch.2 Sec.2, including a transitional source of power/ UPS. The ESD system should have continuous availability R0 as defined in DNVGL-OS-D202 Ch.2 Sec.1 [2.2]and be regarded as a safety system. This implies that the system is both redundant and not vulnerable to a single failure or fail-safe on instrumentation failure as is specified below. Components like valves and actuators, etc. are not required to be redundant. Upon failure of the ESD system, all connected systems should default to the safest condition for the unit or installation. The safest conditions defined in Table 8 normally apply. The table is not intended to be comprehensive, so that other safety-related systems shall also be considered in a similar way. The table is primarily intended for systems shutdown/operations and not individual components within the system. Failures to be considered for the shutdown system should include broken connections and short circuits on input and output circuits, loss of power supply and if relevant loss of communication with other Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 72 Chapter 5 Section 4 Interpretation: Table 8 Safest conditions and corresponding output circuit configuration System Safest condition in case of failure to the shutdown system Output circuit configuration Fire pump drivers (start function) Operational Electrical power generation, including required auxiliary systems, for units not dependent upon active position keeping Shut down Electrical power generation, including required auxiliary systems, for units dependent upon active position keeping Operational 1) NDE Uninterruptible power supplies for power generation, control and safety systems Operational 1) NDE Propulsion and steering for units not dependent upon active position keeping Shut down Propulsion and steering for units dependent upon active position keeping Operational Fire dampers 2) NE 1) 1) NE NE NDE Shutdown NE Utility systems which do not affect safety functions Shut down NE Drilling system Operational 1) 2) 3) 3) NDE Some installations may have multiple operational modes; e.g. storage units intended to transport crude oil to port. In such cases, the safest conditions for each operational mode shall be identified and implemented (e.g. through facilities for by-pass of high level ESD trips during transit). For units dependent upon active position keeping, fire dampers in ventilation inlets for combustion air may be NDE. See DNVGL-OS-E101 for further details The above principles apply for offshore operating condition. However, for mobile units in transit the requirements in MODU Code sec. 14.8 or SOLAS Chapter II-/43 apply. This may imply that relevant ESD actions have to be partially or completely disabled during transit. NDE = normally de-energised NE = normally energised ––––––––––––––– end of Interpretation ––––––––––––––– 6.1.5 Operational after shutdown Equipment which is located in spaces other than enclosed spaces and which is capable of operation after shutdown shall be suitable for installation in zone 2 locations. Such equipment which is located in enclosed spaces should be suitable for its intended operation (See MODU code 6.5.5) Interpretation: The term ‘capable of operation after shutdown’ should be understood to mean ‘operational after ESD high level’. It should be possible to isolate non-Ex equipment in naturally ventilated areas upon gas detection. The shutdown may be manual or automatic depending on the operational philosophy of the unit. Exemption is the equipment listed in 2.1.5. Suitable equipment should be understood to be certified by an independent laboratory. If this is not possible, the suitable should be assessed on a case-by-case basis. Rooms with safety critical non-Ex equipment should have at least two doors towards outside areas effectively forming a semi-airlock. Spaces with only one barrier against gas ingress should have only Ex-equipment. Typical living quarter design may meet this requirement, other enclosed spaces will be specially considered based on the above principles. Unconfirmed gas detection should initiate alarm in the crane cabin. Non-operational cranes should be automatically de-energised if hydrocarbon gas is detected anywhere. Operational cranes should be subject to manual isolation of uncertified electrical equipment and other ignition sources after securing Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 73 Chapter 5 Section 4 systems. In this case, ‘circuit’ is defined as any signal transfer facility, e.g. electrical, pneumatic, hydraulic, optical or acoustic. ––––––––––––––– end of Interpretation ––––––––––––––– Guidance note: This early warning to crane operator should give the operator enough time to secure the load and avoid possible suspended load if power to crane is lost as a result of rapid escalation of the event. For units with dedicated extract systems for shale shaker and mud tanks, gas detection from these systems does not require alarm to crane operator, neither tripping of welding sockets in non-essential temporary equipment as specified in Interpretation 3 resp. 5. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- At least the following facilities shall be operable after an emergency shutdown: 1) emergency lighting for half an hour 2) general alarm system 3) public address system 4) battery-supplied radio communication installations 5) Blow-out preventer (Ref. MODU code 6.5.5) Interpretation: The safety critical systems listed may be non-Ex provided that the ventilation to the room where the equipment is located is shut down and the room is efficiently isolated against gas ingress. Since emergency lighting should be available for half an hour, there is no point in keeping the remaining items operable for longer since nobody can see anything and are assumed to have left the unit. Thus, 30 minutes would be sufficient. ––––––––––––––– end of Interpretation ––––––––––––––– Guidance note: Item 4 of the requirement implies Ex-proof antennas for the applicable battery-supplied radio communications. Antennas with a transmission power below 6 Watts can be regarded as such (See IEC 60079-0,Sec. 6.6.1). Item 4 does not require that all battery powered radio communication remains operable. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 6.2 Emergency control 6.2.1 Back-up means of operation Where the normal user interface for the below listed safety functions is an operator station in an integrated system, a back-up means of operation/user interface is required. This applies to: — emergency shutdown systems (ESD) — fire and gas detection system — activation of relevant fire-fighting systems — other safety functions where a back-up means is required by the rules or standards The back-up means of operation shall be independent of the normal user interface and its communication networks. Interpretation: The back-up means of operation should be based on proven and reliable design and be: — located adjacent to the normal operating position — for all activation signals and other ESD related signals needed to ensure activation, hardwired Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 74 Chapter 5 Section 4 of load. Confirmed gas detection at the crane ventilation intake should initiate automatic isolation of the crane. ––––––––––––––– end of Interpretation ––––––––––––––– Guidance note: The back-up means of operation is typically achieved by provision of a CAAP (critical alarm and action panel). ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 6.2.2 Emergency control room At least two emergency control stations shall be provided. One of the stations shall be located near the drilling console and the second station shall be at a suitable manned location outside the hazardous areas, normally on the bridge or CCR (See DNVGL-OS-A101 Ch.2 Sec.6 [2.5.1]). The control stations shall be provided with: — manually operated contact makers for actuating the general alarm system — an efficient means of communication between these stations and all manned locations vital to the safety of the vessel — emergency shutdown facilities. (See DNVGL-OS-A101 Ch.2 Sec.6 [2.5.2]) At least two BOP control panels shall be provided. One panel shall be located in the drilling control room and one panel shall be on the bridge/CCR or in the toolpusher’s office. For panels located outside the bridge/ CCR, efficient means of communication between these locations and all manned locations vital to the safety of the vessel shall be provided. (See DNVGL-OS-A101 Ch.2 Sec.6 [2.5.3]) 7 Communication and alarms 7.1 Communication The required internal communication systems shall be capable of being supplied from the emergency source of power, for a period of at least 18 hours. A voice communication system shall be provided between the central jacking control station and a location at each leg in self-elevating units. The unit or installation shall be equipped with a public address system. The alarm system may be combined with the public address system, provided that: — alarms automatically override any other input — volume controls are automatically set for alarm sounding — all parts of the public address system (e.g. amplifiers, signal cables and loudspeakers) are made redundant — redundant parts are located or routed separately — all loudspeakers are protected with fuses against short circuits. 7.2 Alarms The following distinctive alarms shall be provided where relevant: — abandon unit — general emergency/muster covering fire and hydrocarbon gas detection — toxic gas (e.g. hydrogen sulphide) detection. All alarms shall be indicated visually and audibly in the control center. The number of alarms during abnormal conditions shall be assessed and reduced as far as practicable by alarm processing/suppression techniques in order to have operator attention on the most critical alarms Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 75 Chapter 5 Section 4 individually directly to the respective controller. The alarms shall be clearly audible at all locations on the unit or installation, and shall be easily distinguishable. If noise in an area prevents the audible alarm being heard a visible means of alarm shall be provided. See IMO Resolution A.830(19) Code on Alarms and Indicators, 1995 for details on priorities, grouping, locations and types, including colours, symbols etc. Guidance note: National authorities may have specific requirements deviating from the IMO Resolution. These will normally be acceptable for classification purposes. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Alarm to areas which are not regularly manned (e.g. cofferdams, tanks) may be covered by procedural precautions, e.g. using portable radios. Activation of the general alarm shall be possible from the main control stations, including navigation bridge and radio room. Requirements for alarms in connection with watertight doors and release of hazardous fire extinguishing medium are given in DNVGL-OS-C301 and DNVGL-OS-D301. The alarm system shall be regularly tested. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 76 Chapter 5 Section 4 that require operator action. 1 General 1.1 Introduction This chapter provides principles for design, construction and installation of fire protection of offshore units and installations. The table below lists references required for a complete understanding of this chapter. Table 1 Overview of applicable standards Reference Title IMO MODU Code Code for the construction and equipment of Mobile Offshore Drilling Units, 2009 IMO FSS Code International Code for Fire Safety Systems DNVGL-OS-A101 Safety Principles and Arrangements DNVGL-OS-D101 Marine and Machinery Systems and Equipment DNVGL-OS-D202 Automation, Safety, and Telecommunication Systems DNVGL-OS-D301 Fire protection 1.2 Application A Mobile Offshore Unit Safety Certificate is issued by an Administration or authorized organization other than DNV GL is accepted as evidence that the unit is in accordance with the requirements of this Chapter. Where the Administration has authorized DNV GL to issue the MOU safety certificates on its behalf, DNV GL will give effect to the fire protection, detection and extinction requirements following the descriptions of this chapter. 1.3 Plans and data to be submitted A general overview of the required plans and analyses to be submitted is listed in Table 2. A more detailed overview, tuned to the specific design and project scope can be obtained from DNV GL’s Nauticus Production System. Table 2 Documentation requirements Object Fire resisting and noncombustible materials Documentation type Additional description M020 – Material specification, fire related properties Surface materials, insulation materials, primary deck coverings, textiles, furniture and bedding. Info AP G060 – Structural fire protection drawing AP V060 – Penetration drawings AP Machinery space fire doors M020 – Material specification, fire related properties AP Structural fire protection of drilling area structure Z110 – Data sheet AP Structural fire protection arrangements Fire and gas detection and alarm systems Fire detection and alarm system Hydrocarbon gas detection and alarm system, fixed G130 – Cause and effect diagram AP G150 – Design philosophy AP I200 – Control and monitoring system documentation AP Z030 – System arrangement plan AP I200 – Control and monitoring system documentation AP Z030 – System arrangement plan Detectors, call points and alarm devices. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS AP Page 77 Chapter 5 Section 5 SECTION 5 FIRE PROTECTION Object Fire water system Machinery spaces fixed water spraying fire extinguishing system Drilling area water spraying fire extinguishing system Documentation type Additional description Info S011 – Piping diagram AP S030 – Capacity analysis AP Z030 – System arrangement plan AP G200 – Fixed fire extinguishing system documentation AP G100 – Escape and evacuation study AP External surface protection water spraying system Emergency escape Assembly station / muster Z030 – System Arrangement plan station / temporary refuge space AP Escape route AP G120 – Escape route drawing For general requirements to documentation, including definition of the Info codes, see DNVGL-CG-0168 Sec.1. For a full definition of the documentation types, see DNVGL-CG-0168 Sec.2. 2 Principles A Mobile Offshore Unit Safety Certificate issued by an Administration or authorized organization other than DNV GL is accepted as evidence that the unit is in accordance with the requirements of this Chapter. Where the Administration has authorized DNV GL to issue the MOU safety certificates on its behalf, DNV GL will give effect to the fire protection, detection and extinction requirements following the descriptions given in DNVGL-OS-D301 (principles, technical requirements and guidance for design, manufacturing and installation). This standard meets and is based on the regulations of the MODU code 2009. Wherever, the MODU code requirements leaves room for interpretation, the DNVGL-OS-D301 standard completes the Code with additional specific requirements. 3 Passive fire protection Passive fire protection is as required by MODU code 9.2, Structural fire protection. Specific requirements for machinery systems and equipment are given is DNVGL-OS-D101 Ch.2 Sec.1 [1.5]. Fire protection measures for cables are given in DNVGL-OS-D301 Ch.2 Sec.2 [4] and DNVGL-OS-D101 Ch.2 Sec.10 [3.4]. Openings and penetrations in fire rated divisions shall be arranged so as to maintain the fire rating of the divisions. Penetrations shall be approved for the actual divisions where they are to be installed. Openings in bulkheads of “H” class are in general to be avoided. 4 Fire fighting systems 4.1 Fire pumps, fire mains, hydrants and hoses MODU code Ch.9, Sec.7 applies for fire pumps, fire mains, hydrant and hoses with the following remarks: — It is acceptable that the fire water system is supplied from a header supplied from a leg well suction raw water system. — If installed, the lowest water level to assure supply of water from each of any two fire hydrants, hoses and 19 mm nozzles while maintaining a minimum pressure of 0.35 N/mm2 at any hydrant for 15 minutes. Minimum tank capacity (below lowest automatically maintained water level) shall be 10 m3. Minimum one of the raw water pumps shall be arranged for automatic operation. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 78 Chapter 5 Section 5 Table 2 Documentation requirements (Continued) Minimum tank capacity to be compatible to fire water supply for all fire pump running modes as e.g. start-up in case the dimensional fire scenario. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- — In interpretation of MODU code 9.7.17, use of GRE/GRP material in firewater ring main, we refer DNVGLOS-D101 Ch.2 Sec.2 [2.5.5] — In interpretation of MODU code 9.7.14, The isolating valves shall be provided for easy access of operation. Where the isolation valves are remotely operated, manual operation shall be possible locally. For the self-elevating units, the following additional fire water supply measures shall be provided: a) Water shall be supplied from sea water main filled by at least two submersible pumping systems. One system failure will not put the other system(s) out of function, and b) Water shall be supplied from drill water system while unit lifting or lowering. Water stored in the drill water tank(s) is not less than 40 m3 plus engine cooling water consumptions before unit lifting or lowering. Alternatively, water may be supplied from buffer tank(s) in which sea water stored is not less the quantity as the above mentioned. (See IACS D11.2.4) 4.2 Active fire protection of specific areas MODU code Ch.9, Sec.7 and SOLAS II-2 applies for active fire protection of specific areas like accommodations, service and working spaces and machinery spaces. More details on the installation requirements for active fire protection is given DNVGL-OS-D301 Ch.2 Sec.2 and 6 as follows: Table 3 Installation requirements for active fire protection - references Description Reference in DNVGL-OS-D301 Ch.2 Sec.2 and 6 Accommodation, service and working spaces and control stations Sec.2 [2.1] Machinery spaces Sec.2 [2.2] Lockers containing flammable liquids Sec.2 [2.3] Storage of gas cylinders Sec.2 [2.4] Drilling areas Sec.6 [3.2] Processing areas Sec.6 [3.3] 4.3 Fire fighting systems of specific types Requirements for fire fighting systems based on MODU code Ch.9 Sec.7 and the relevant FSS code chapters complemented with interpretations, are given in the DNVGL-OS-D301 Ch.2 Sec.3 as follows: Table 4 Description Reference in DNVGL-OS-D301 Ch.2 Sec.3 Fire water pump [2.2] Fire main [2.3] Fire hydrants and hoses [2.4] Fixes gas fire fighting [3.1] Fixed foam [3.2] Water mist [3.3] Deluge systems [3.4] Sprinkler systems [3.5] Monitors [3.5] Portable equipment [4] Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 79 Chapter 5 Section 5 Guidance note: In line with the fixed automatic gas detection system requirement of MODU code 9.8.1, a permanently installed automatic system shall be provided for detection of: — Hydrogen sulphide gas in the following areas: — shale-shaker area — mud tank area — drill floor — above or in the mud flow line. — Hydrocarbon gas in: — hazardous areas, except in zone 0 and areas mechanically ventilated — ventilation outlets from hazardous areas having mechanical ventilation — intakes for ventilation air. If single fire or gas detectors are used for each detection area, fail safe action should be taken on instrument failure, meaning confirmed fire or gas. Guidance note: If shutdown logic requires no shutdown action on confirmed fire/gas detection, detector failure should also only give alarm with equal priority. Normally local HVAC should be tripped on gas detection in the inlets and then detector failure should also cause HVAC trip. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- The detection system shall give both audible and visual alarm in the main control room and on the drill floor. The system is clearly to indicate where gas has been detected. Visual indication of the gas concentration shall be given in the main control room. 6 Escape At least one escape route from the drilling derrick and from driller's cabin should lead directly to a safe place without requiring personnel entry to the central drill floor area. Otherwise as required in DNVGL-OS-A101 Ch.2 Sec.5 as listed below. Table 5 Description Reference in DNVGL-OS_A101 Ch.2 Sec.5 Escape routes [2] Muster areas [3] Emergency lighting [4] Marking and warning signboards [5] Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 80 Chapter 5 Section 5 5 Fire and gas detection systems 1 Introduction 1.1 General This chapter summarizes the specific requirements for the Enhanced Control & Safety Systems (ES) notation as identified in the previous chapters. 1.2 Objective The objective of the ES notation is to increase safety over MODU Code and main class safety level in a cost effective way. 1.3 Scope ES covers the following: — enhanced ESD — fire safety systems — refrigeration plants — alarm philosophy All of the technical requirements as listed in this chapter come in addition to MODU Code 2009 and main class requirements as described in the remaining of this rule book. 1.4 Application The requirements for ES as listed in this section are only applicable for vessels with the voluntary class notation ES. 1.5 Documentation requirements Documentation shall be submitted as required by Table 1. Table 1 Documentation requirements Object Documentation type Unit G130 – Cause and effect diagram Additional description Info AP Unit Z050 – Design philosophy AP For general requirements to documentation, including definition of the Info codes, see DNVGL-CG-0168 Sec.1. For a full definition of the documentation types, see DNVGL-CG-0168 Sec.2. 2 Technical requirements All of the technical requirements as listed in Table 2-1 come in addition to MODU Code 2009 and main class and additional service notation requirements as described in the remaining of this Part. Table 2 Requirements applicable for ES only Description Reference Enhanced ESD DNVGL-OS-A101 Ch.3 Sec.1 Refrigeration plants DNVGL-OS-D101 Ch.3 Sec.1 Alarm philosophy DNVGL-OS-D202 Ch.3 Sec.1 Active fire protection for moon pool Enhanced fire protection DNVGL-OS-D301 Ch.3 Sec.1 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 81 Chapter 5 Section 6 SECTION 6 ENHANCED SYSTEMS Chapter 5 Section 6 3 Certification of materials and components There are no additional requirements for certification of materials and components. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 82 SECTION 1 PROCEDURES 1 Introduction The scope of classification requires that specified materials, components and systems intended for the vessel are certified according to the rules. The objective of certification shall ensure that materials, components and systems used in vessels classed by DNV GL, comply with the rule requirements. This chapter describes the different types of certification and the involvement of DNV GL. The table below lists references required for a complete understanding of this chapter. Table 1 Overview of applicable standards Reference Title DNVGL-OS-A101 Safety principles and arrangements DNVGL-OS-D101 Marine and machinery systems and equipment DNVGL-OS-D201 Electrical installations DNVGL-OS-D202 Automation, safety, and telecommunication systems DNVGL-OS-D301 Fire protection 2 Certification types Certification of materials, components and systems will be documented by the following types of documents: — DNV GL Product Certificate (VL): A document signed by a surveyor of DNV GL stating: — conformity with rule 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. — Works Certificate (W) A document signed by the manufacturer stating: — conformity with rule 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. — Test Report (TR) A document signed by the manufacturer stating: — conformity with rule requirements — that tests are carried out on samples from the current production. The applicable chapters and sections of the rules specify which of the above mentioned documents are required, how the products should be marked and which technical standards and requirements apply. More details are given in Sec.2 of this part. 3 Class involvement To ensure an efficient, cost effective and correct certification process, a certification agreement shall normally be established between DNV GL and the manufacturer of VL certified products. Such agreement may be part of a manufacturing survey arrangement (MSA) and shall include information on the procedures Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 83 Chapter 6 Section 1 CHAPTER 6 CERTIFICATION Marine and machinery systems and equipment will be certified or classified based on the following main activities: — design verification — equipment certification — survey during construction and installation — survey during commissioning and start-up. 4 Certification in operation When machinery components are renewed, such components should in general be delivered in accordance with requirements as per valid rules at the time of newbuilding. (See Rules for drilling units Ch.3 Sec.2 [3.2.1]) Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 84 Chapter 6 Section 1 for plan approval and survey and to specify information that shall be transferred between the customer and the Society. A more detailed description plan approval, type approval, survey and MSA are given in Rules for drilling units Ch.1 Sec.6 [2]. 1 General This chapter gives an overview of the certification requirements for machinery and systems. 2 Principles Equipment shall be certified consistent with its functions and importance for safety, categorized as follows: — Category I: equipment related to safety for which a DNV GL certificate is required. — Category II: equipment related to safety for which a works certificate prepared by the manufacturer is accepted. Equipment for non-essential systems does not need to be certified but shall be delivered with documentation as for equipment Cat. II. Table 1 Scope Cat 1A Cat 1B Cat 1C Cat 2A Cat 2B D S2 R2 D S1 R2 S1 R2 R2 R1 VL VL VL W TR Certificate / Document D: Design review S1: Witness of final testing of completed product S2: Survey during construction and witness of final testing of completed product R1: Review of manufacturers documentation (typical for product) R2: Review of manufacturers documentation (specific to product) The extent of required survey by DNV GL shall be decided on the basis of manufacturer's QA/QC system, manufacturing survey arrangement (MSA) with DNV GL and type of fabrication methods. Guidance note: It should be noted that the scopes defined for category IA and IB are typical and adjustments may be required based on considerations such as: — standard type approved products / MSA agreement — complexity and size of a delivery — previous experience with equipment type — maturity and effectiveness of manufacturer's quality assurance system — degree of subcontracting. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Equipment of category II is normally accepted on the basis of a works certificate prepared by the manufacturer. The certificate shall contain the following data as a minimum: 1) equipment specification or data sheet 2) limitations with respect to operation of equipment 3) statement (affidavit) from the manufacturer to confirm that the equipment has been constructed, manufactured and tested according to the recognized methods, codes and standards. Test report to be included in work certificates for diesel engines. 4) A test repost (TR) may be issued based on testing carried out on samples from the current production of equal products. Guidance note: Independent test certificate or report for the equipment or approval certificate for manufacturing system may also be accepted. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 85 Chapter 6 Section 2 SECTION 2 MACHINERY AND SYSTEM CERTIFICATION 3.1 General Piping and piping components shall be delivered with material certification in accordance with Table 2. Where the requirement calls for witness by 3rd party (Certificate Type 3.2) this shall be carried out by DNV GL. Table 2 Component Material Class of piping system Nominal diameter (mm) Type of documentation Design temperature (°C) 3.2 certificate Pipes 1) I > 50 II, III > 50 I, II, III ≤ 50 Flanges and bolts 3.1 certificate 2.2 report x x x > 400 x ≤ 400 Bodies of valves and fittings 1), source materials of steel expansion bellows, other pressure containing components not considered as pressure vessels Steel I Steel or nodular cast iron I, II > 100 > 400 ≤ 100 > 400 > 100 ≤ 400 ≤ 100 ≤ 400 x x x x x III Cast iron III Copper alloys I, II x x > 50 x ≤ 50 x III Pump housings x I x II, III x 2.2 Test report: Confirmation by the manufacturer that the supplied products fulfill the purchase specification, and test data from regular production, not necessarily from products supplied 2.2 3.1 Inspection certificate (Works Certificate): Test results of all specified tests from samples taken from the products supplied. Inspection and tests witnessed and signed by QA department 3.1 3.2 Inspection certificate (Test Certificate): As work certificate, inspection and tests witnessed and signed by QA department and an independent third party body 1) Pipes and bodies of valves fitted on unit or installation's side and bottom and bodies of valves fitted on collision bulkhead shall be provided with documentation as required for class II piping systems. (Valves to hydraulic pressure tested in the presence of a DNV GL Surveyor) 3.2 Miscellaneous mechanical components Certification requirement for miscellaneous machinery mechanical components are given in the table below. Table 3 Item Certification category Boiler 1A Condenser 2A Boiler heat exchanger 1A Pumps for boiler 1C Boiler PSV 1C Boiler spark arrestor 2B Winches 1A Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 86 Chapter 6 Section 2 3 Machinery systems and equipment (Continued) Hydraulic Cylinders pD > 20 000 1) 1A Hydraulic Cylinders pD ≤ 20 000 2A Compressor 2) 1) 2) Hydraulic cylinders for cleating and manoeuvring of watertight doors and hatches shall be delivered with certificate of category 1A regardless of pressure and size. Cleating cylinders where the locking mechanism is placed inside the cylinder shall be type approved. p = design pressure (bar) D = internal diameter of cylinder tube (mm) Compressors to be certified in accordance with DNV Rules for ships Pt.4 Ch.5 Sec.4. 3.3 Pressure vessels Certification requirement for pressure vessels are given in the table below. Table 4 Property Conditions Category I 2) II X 20000 1 < P ≤ -----------------------D i + 1000 Pressure 20000 P > -----------------------D i + 1000 Medium Material X Vacuum or external pressure X Steam X Toxic fluid X Thermal oil X Liquids with flash point below 100°C X Flammable fluids with T > 150°C X Other fluids with T > 220°C X Compressed air/gas PV ≥ 1.5 X σy 360 MPa (50 000 psi) or σt 515 MPa (75 000 psi) X Where impact testing is required. X Free standing structural storage tanks will be specially considered based on stored medium, volume and height. These may be designed according to the requirements of DNVGL-OS-C101. Normally category IA, however, limited class survey may be agreed upon with DNV GL based on manufacturer's QA/ QC system, manufacturing survey arrangement (MSA) and fabrication methods. P = internal design pressure in bar Di = inside diameter in mm V = volume in m3 T = design temperature σy = specified yield strength σt = specified ultimate tensile strength 3.4 Main and emergency power Certification requirements for main and emergency power is given in the table below. Table 5 Component Category Engines for main power, emergency power, auxiliary power 1A The individual components within the equipment train and other auxiliary systems are to be certified as required elsewhere in the rules, e.g. HVAC, and fire protection. Requirements for testing, inspection and documentation are described in DNV Rules for ships Pt.4 Ch.3 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 87 Chapter 6 Section 2 Table 3 Chapter 6 Section 2 Sec.1 as detailed in the table below. Table 6 Description Reference in DNV Rules for ships Pt.4 Ch.3 Sec.1 Certification of parts C200 Testing and inspection of parts C300 Inspection during assembly C400 Workshop Testing D Shipboard Testing I 3.5 Jacking machinery Jacking machinery shall be certified to category 1A. Requirements for certification and testing of the jacking gears are described in DNV Rules for ships Pt.4 Ch.4 Sec.2 C as follows: Table 7 Description Reference in DNV Rules for ships Pt.4 Ch.4 Sec.2 Certification of parts C100 Pinion and wheels C200 Welded gear designs C300 Ancillaries C400 Assembling C500 3.6 Components in marine and machinery piping systems Certification requirements for components in marine piping system is given in the table below. Table 8 Item Certification category Piping system items for main and emergency power Fuel oil transfer pump 1C Cooling system pump unit 1C Valves Valves for sea inlet or discharge with DN >100 mm 1C Valves with DN >100 mm and p>16 bar 1C Non-standard valves 1B Compressed air systems Starting air compressors 1C Pressure relief valves 2A Ballast system Ballast pumps 1C Ballast control system 1A Bilge and drain system Bilge control system 2A Bilge pumps 1C Bilge ejectors 2A Strainers 2B Strums and rose boxes 2B Air and sounding systems Air vent heads 1B Tank level indicators 2A Sounding control panel 1B Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 88 (Continued) Item Chapter 6 Section 2 Table 8 Certification category Striking plates 2B Sounding rods 2B Leak detection system 2B Hydraulic control of safety critical valves etc. Hydraulic control panel 1B Pumps in hydraulic control system 1C Hydraulic power pack 2A Accumulators (pV > 150 kNm) 1B Accumulators (others) 2A Tanks for hydraulic fluid 2B 4 Electrical installations Electrical equipment serving essential or important functions and cables shall be delivered with certificates as required by Table 6. Additional requirements to certification may be given by other relevant parts of the DNV GL offshore standards. Equipment covered by a valid type approval certificate is generally accepted without further design verification, unless otherwise stated in the certificate. A reference to the type approval certificate shall substitute the required documentation for DNV GL design assessment. A product certificate may be issued based on the type approval certificate and a product survey, unless otherwise stated in the type approval certificate. Table 9 Certification requirements Equipment Rating DNV GL certificate (VL) Main and emergency switchboards all ratings X Distribution switchboards, motor starters, motor control centres, etc. ≥ 100 kW/kVA X Generators4) and transformers ≥ 300 kVA Motors 4) Semiconductor assemblies for motor drives ≥ 10 kW/kVA and < 100 kW/kVA Works certificate (W) X X ≥ 100 kVA and < 300 kVA 1) 2) X ≥ 10 kVA and < 100 kVA X ≥ 300 kW X ≥ 10 kW and < 100 kW X X X ≥ 10 kW and < 100 kW Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS X X ≥ 100 kW and < 300 kW 1) 2) ≥ 100 kW DNV GL type approval cert. (TA) X Page 89 Equipment Rating Semiconductor assemblies for UPSs or battery chargers ≥ 50 kVA Cables 1), 2) 2) 3) 4) Works certificate (W) DNV GL type approval cert. (TA) X < 50 kVA X all ratings Electrical equipment installed in hazardous areas 3) 1) DNV GL certificate (VL) all ratings X - - - As an alternative to the acceptance based on a type approval certificate (TA) and a works certificate (W), the electrical equipment will also be accepted on the basis of a DNV GL product certificate (VL). All cables – except cables for internal use in electrical assemblies or short lengths on mechanical packages. All electrical installations in hazardous areas, and areas that may be become hazardous by accidental release of explosive gas, shall comply with the requirements for certification and documentation given in DNVGL-OS-D201 Ch.2 Sec.11 [2]. Material certificates for shafts shall be issued as required by DNVGL-OS-D101. Note: Heat exchangers used in conjunction with certified electrical equipment, shall be certified as required for pressure vessels, see DNVGL-OS-D101. ---e-n-d---of---n-o-t-e--- Electrical equipment required to be delivered with DNV GL Product Certificate shall be documented as described in the table below. For equipment covered by a valid DNV GL type approval certificate, this certificate may specify exceptions to document approval. Table 10 Documentation requirements Object Documentation type Additional description Cables E110 – Cable data sheet and design drawing For cables not having a DNV GL type approval. AP Electric propulsion motors Shafting documentation as required in DNV Rules for ships Pt.4 Ch.4 Sec.1 A200 Shafting for electric propulsion motors in mechanical propulsion line. AP Shaft generators Shafting documentation as required in DNV Rules for ships Pt.4 Ch.4 Sec.1 A200 Shafting for electric generators in mechanical propulsion line. AP Main and emergency switchboards Info E120 – Electrical data sheet, general FI E140 – Assembly schedules and technical data AP E150 – Strength calculation with respect to short circuit When designed sub-transient short circuit strength exceeds 50 kA r.m.s. FI E160 – Internal arc withstanding report High voltage switchboards only. FI E170 – Electrical schematic drawing AP E180 – Layout of electrical assembly FI E240 – Functional description for electrical assemblies FI Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 90 Chapter 6 Section 2 Table 9 Certification requirements (Continued) Object Semi-conductor assemblies Distribution switchboards, motor starters, motor control centres, harmonic filters etc. Documentation type Additional description Info E120 – Electrical data sheet, general AP E130 – Electrical data sheet, semiconductor assemblies FI E140 – Assembly schedules and technical data AP E180 – Layout of electrical assembly FI E240 – Functional description for electrical assemblies FI Z120 – Test procedure at manufacturer AP E120 – Electrical data sheet, general AP E140 – Assembly schedules and technical data AP E150 – Strength calculation with respect to short circuit When designed sub-transient short circuit strength exceeds 50 kA r.m.s. FI E160 – Internal arc withstanding report High voltage switchboards only. FI E170 – Electrical schematic drawing AP E180 – Layout of electrical assembly FI I020 – Control system functional description AP I030 – Block diagram AP Systems for automatic start and I050 – Power supply arrangement stop of generator drivers and for automatic operation of I080 – Data sheet with breakers. environmental specifications Z120 – Test procedure at manufacturer AP AP AP For general requirements to documentation, including definition of the Info codes, see DNVGL-CG-0168 Sec.1. For a full definition of the documentation types, see DNVGL-CG-0168 Sec.2. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 91 Chapter 6 Section 2 Table 10 Documentation requirements (Continued) The certification requirement of the various instrumented systems shall follow the same certification requirement as the Equipment Under Control. Major units of equipment associated with essential and important control and monitoring systems, as specified in the rules, shall be provided with a product certificate unless exemption is given in a DNV GL issued Type Approval Certificate or the logic is simple and the failure mechanisms are easily understood. The above applies for computer based systems as well. For DNV GL type approved systems, additional testing is only required for the application software programming and function and where specified explicitly in the type approval certificate. The certification procedure normally consists of: 1) Document evaluation — review of documentation for the appropriate system. 2) Manufacturing survey (MS) — survey of hardware and software. 3) Test of project specific application software. 4) Issue of a DNV GL product certificate. Guidance note: Type approval of systems includes hardware, operating system software, standard software modules and standard function blocks. If new software modules or function blocks are made, testing will be required. Application software is project specific and shall be tested before the certificate can be issued. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- The certification requirement of the various instrumented systems shall follow the same certification requirement as the system they control. Integrated control and safety system shall always be certified. Guidance note: For equipment, where failure in the automation and safety functions may lead to major incidents, the automation and safety system shall be certified, e.g. burner control for auxiliary boilers. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 6 Fire protection Categorization of safety critical equipment is given in the table below. Equipment that is considered important for safety, which is not listed, shall be categorized after special consideration. Table 11 Categorization of safety critical equipment Component Category IA IB II Fire dampers, penetrations Fire water pumps incl. drivers Type Approved X 2 Components in fire extinguishing system X 1 Fire hose X Hose reels and associated equipment X Nozzles X Monitors X Fixed fire fighting installations X Other fire-fighting installations, e.g. deluge, powder or systems not covered by IMO 3 X Insulation materials in fire resisting divisions X Fire rated doors X Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 92 Chapter 6 Section 2 5 Automation and control system Component Category Fire rated windows X Fire and gas detectors X Wheeled and portable extinguishing system X Fire extinguishing media X 1 To follow requirements as given in DNVGL-OS-D101 and/or type approval certificate. 2 Fire water pump (directly driven) is considered Cat. IB. Fire water lift pump (not directly driven) of proven design may be accepted by conformation of material, witness of testing and review of fabrication documentation. 3 Normally function test to be carried out at yard. 7 Watertight/ weathertight integrity Certification requirements for components related to water- and weathertight integrity as given in DNVGLOS-C301 Ch.3 Sec.1 [3.2] are listed in the table below. Table 12 Certification requirements for components related to water- and weathertight integrity Component Category IA Watertight doors and hatch covers IB II X Weathertight doors and hatch covers1) X Side scuttles and windows X Automatic closing devices for air pipes X Valves for sea inlet or discharge X Hydraulic system for watertight closing appliances X Accumulator, hand pumps X Control and monitoring systems for watertight closing appliances X 1) In addition to the Work Certificate a design approval performed by DNV GL is required. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 93 Chapter 6 Section 2 Table 11 Categorization of safety critical equipment (Continued) SECTION 1 INTRODUCTION 1 Overview This part gives an overview of the class requirements as relevant for the building site. 2 Structure After the principles given in this chapter, Sec.2 continues with the required survey planning defining the class involvement on site in the remaining of the new building process. Sec.3 thereafter describes class requirements regarding fabrication and testing of the structure. Sec.4 continuous with a detailed description of the class related work process during mechanical completion, testing and commissioning. Sec.5 concludes with an overview of the deliverables from class after commissioning of the unit. For a complete understanding of this chapter is referred to the Rules for drilling and supports units and the standards and class guidelines as listed in Table 1. Table 1 Overview of applicable standards and class guidelines Reference Title DNVGL-RU-OU-0101 Rules for Offshore drilling and support units DNVGL-OS-A101 Safety principles and arrangements DNVGL-OS-C301 Stability and watertight integrity DNVGL-OS-C401 Fabrication and testing of offshore structures DNVGL-OS-D101 Marine and machinery systems and equipment DNVGL-OS-D201 Electrical installations DNVGL-OS-D202 Automation, safety, and telecommunication systems DNVGL-OS-D301 Fire safety DNVGL-CG-0169 Quality survey plan (QSP) for offshore class new-building surveys DNVGL-CG-0170 Offshore classification projects - testing and commissioning 3 Principles Basis principles for the involvement of class during new building are given in DNVGL-RU-OU-0101 Ch.1 Sec.4. Table 2 Basis principles for the involvement of class during new building Description Reference in DNVGL-RU-OU-0101 Ch.1 Sec.4 Requirements for builder or designer [1.2] Applicable rules [1.3] Plan approval [1.4] Survey during constructions [1.5], see Sec.2 regarding planning Installation of systems and equipment [1.6], see Sec.4 Testing and commissioning [1.7], see Sec.4 Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 94 Chapter 7 Section 1 CHAPTER 7 NEWBUILDING SURVEY 1 Objective The objectives of survey planning are to: 1) ascertain various activities that are necessary for the classification of a unit 2) to identify customer’s, DNV GL’s and various standards and procedures that are applicable to those activities 3) to define the extent of involvement by the customer and DNV GL. 2 Scope This section applies to the offshore construction activities at any of the following: 1) customer’s construction facilities 2) subcontractors at the customer’s construction facilities 3) subcontractors at their own facilities or at other remote locations. It does not cover the certification of equipment and materials. 3 Quality survey plan 3.1 Introduction The objectives as listed above are met by the definition and further processing of a so called Quality Survey Plan (QSP). This QSP is defined after a review of the construction facility, and is further discussed and agreed during a new-building survey planning-kick off meeting. These phases are discussed in more detail in the remaining of this section. 3.2 Review of the construction facility DNV GL shall familiarize itself with the Customer’s production facilities, management processes, and safety procedures. This familiarization shall take place prior to starting any fabrication or construction. Such familiarization will take place under the following circumstances: 1) Where DNV GL has no recent experience at the construction facility (typically after a lapse of one year) or when a significant new infrastructure to the facility has been added 2) Where there has been a significant management or personnel restructuring, having an impact on the ship or offshore construction processes or, 3) Where the builder contracts to construct a vessel of a different type or substantially different in design. In order to assess compliance with specified Rules, Standards and Regulations, the Society may require additional documentation and carry out an assessment of yard’s processes, systems, and personnel related to the classification projects. The results of the assessment should be used as a basis to decide on the extent of the involvement of surveyors of the Society. The extent of the Classifications Society’s involvement for the site survey activities shall be clearly documented in a so called Quality Survey Plan (QSP). A draft format for such a plan is given in DNVGL-CG-0169, Table 5-1. Where DNV GL has no recent experience with new building activities at the builder’s construction facility or its subcontractors and/or when significant new infrastructure has been added, DNV GL may initiate an MPQA and evaluate the Customer’s QA/QC-performance and set the initial survey scope on basis of the MPQA rating methodology. 3.3 New building survey planning 3.3.1 Kick off meeting Prior to commencement of any new building project, the Customer and DNV GL are to discuss at a kick-off meeting the survey activity items listed as documented during the review of the facility (see above). The Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 95 Chapter 7 Section 2 SECTION 2 SURVEY PLANNING A record of the meeting is to be made, based upon the contents of the Table, (the table can be used as the record with comments made inserted in the appropriate column). The Customer may be asked to agree to undertake ad hoc investigations during construction where areas of concern arise. DNV GL is to be kept informed of the progress of any investigation. Whenever an investigation is undertaken and, if warranted by the severity of the problem, the Customer should suspend relevant construction activities until counteractive measures are satisfactorily implemented, reviewed and accepted by the Society. 3.3.2 Quality standards Construction quality standards for the hull structure, piping, electrical, HVAC and other disciplines during new building project shall be properly listed in this document, reviewed and agreed during the kick-off meeting. 3.3.3 Survey extent It shall be underscored that the QSP table is not exhaustive, and in cases where the QSP is incomplete and/ or not necessarily covering all survey aspects, it shall be the prerogative of DNV GL to require such activities/items added. The QSP only covers survey activities and does not cover the technical interpretations of the statutory requirements or approval of plans, designs and manuals required by the Regulations. It should be noted that the level of DNV GL involvement indicated on the QSP takes account of the activities of others, and DNV GL reserves the right to adjust its level of involvement if reduced involvement by others is experienced or if the requisite quality is not achieved. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 96 Chapter 7 Section 2 purpose is to agree how the list of specific activities shown in the Table is sufficiently comprehensive, to be adjusted, if necessary and to be addressed. 1 Principles The principles of fabrication of structures are described in DNVGL-OS-C401 and are further detailed in the remaining of this chapter. 2 Technical provisions Technical provisions regarding the fabrication of structures are described in DNVGL-OS-C401 Ch.2 as detailed below. Table 1 Description Reference in DNVGL-OS-C401 Ch.2 Welding Procedures and Qualification of Welders Sec.1 Fabrication and Tolerances Sec.2 Non-Destructive Testing Sec.3 Other Tests Sec.4 Corrosion Protection Systems Sec.5 Bolts Sec.6 [2] Mechanical fastening Sec.6 [3] 3 Certification and classification Welding of special, primary and secondary structures for hull, welding of superstructure, and equipment shall be carried out by certified approved welders, with approved welding consumables and at contractors recognised by DNV GL. Detailed requirements are given in DNVGL-OS-C401 Ch.2 as detailed below. Table 2 Description Reference in DNVGL-OS-C401 Ch.2 Sec.3 Contractors [2.3] Welding consumables [2.4] Welding procedures and qualification of welders [2.5] Corrosion protection systems [2.6] Non-destructive testing [2.7] Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 97 Chapter 7 Section 3 SECTION 3 FABRICATION OF STRUCTURES 1 Introduction This chapter provides an overview of the total commissioning process of a self-elevating units and the involvement of class in this process. 2 Principles Where specified by the rules, testing shall be carried out in the presence of a surveyor, and related requirements for test programmes shall be observed. A test programme for harbour and jack-up trials shall be prepared by the customer and accepted by the Society. The programme shall specify systems and components to be tested, and the testing procedure. The Society may, in order to verify rule compliance, request additional tests and/or data to be recorded. Procedures for pre-commissioning, testing and commissioning for all the systems onboard that are covered by the scope of classification shall be prepared by the customer and accepted by the Society. The tests shall give evidence as to satisfactory operation and performance in accordance with the rules. When testing control and safety systems, failure modes shall be simulated as realistically as possible. The extent of participation in the mechanical completion and commission activities by the Society shall be clearly identified in the Quality Survey Plan (QSP) submitted by the customer and accepted by the Society. The extent of participation is limited to ensure compliance with the requirement of Classification Rules and applicable statutory requirements. Final acceptance of commissioning is the owner’s responsibility. 3 Process The total commissioning process is described in DNVGL-CG-0170. Table 1 Description Reference in DNVGL-CG-0170 Sec.2 Detailed design [1] Mechanical Completion [1] Commissioning [1] Integration testing [1] Marine sea trial [1] Delivery [1] Hook up [1] Operation [1] 4 Survey scope categories The survey scope during testing and commissioning defining DNV GL’s involvement shall be categorized as follows: — Survey Category 1 – Statutory and Essential Systems for Safety (normally increased attendance by DNV GL). — Survey Category 2 – Main Systems / Functionally Important (For Main and Additional Class Notations extent is based on the yard’s experience and the effectiveness of Yard’s QA/QC system). — Survey Category 3 – Normally limited or no attendance required by surveyor. Examples of tables detail the survey categorization of Marine Systems and drilling systems are given in Appendix C3 of DNVGL-CG-0170. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 98 Chapter 7 Section 4 SECTION 4 COMMISSIONING PROCESS Detailed test requirements for marine, utility and safety systems are given in the different Chapter 3 of DNVGL-OS-D101, DNVGL-OS-D201, DNVGL-OS-D202 and DNVGL-OS-D301. An overview of these is given in DNVGL-CG-0170 App.F as listed in the table below. Table 2 Description Reference in DNVGL-CG-0170 Stability and Watertight Integrity App.F.1 Fabrication and Testing of Offshore Structures App.F.2 Marine and Machinery Systems and Equipment App.F.3 Electrical Installations App.F.4 Instrumentation and Telecommunication Systems App.F.5 Fire Protection Systems App.F.6 6 Jacking trials In addition to the above a jacking trial shall performed according to an approved jacking trial plan and as covered by the QSP. The trial shall cover the correct functioning of the jacking machinery and other relevant items. The jacking machinery shall be tested with the highest specified design lifting load. The duration shall at least reflect one operating cycle from transit condition to the top of the legs and down again. The jacking trial shall verify the alignment of the racks and pinions and guides. The following systems shall be tested: — jacking brake arrangement — alarm and monitoring arrangement for the jacking machinery, supporting equipment and unit safety during jacking — fail safe arrangement of the jacking machinery and any interlock safety arrangement — essential systems and equipment used for normal jacking operations. After trials, the structure including leg footing connection, guides, jackhouses, jacking gear arrangement to be surveyed to the satisfaction of the surveyor. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 99 Chapter 7 Section 4 5 Test requirements related to marine, utility and safety systems 1 Class certificate When DNV GL is satisfied that the requirements specified for the unit in question have been met, the appropriate class notation will be assigned and confirmed by the issuance of a classification certificate. Provided the requirements for retention of class are complied with, the certificate will normally have a validity of five years. 2 Conditions of class Class may be assigned with conditions of class. These conditions may apply for equipment subject to class approval not readily commissioned in accordance with approved testing and commissioning procedures. The outstanding testing and commission procedures should be minor of nature. Conditions of class do not apply for critical systems e.g., fire fighting/detection, life-saving appliances and navigational aids. If these are not commissioned, class and statutory certificates are typically not issued. 3 Appendix to class certificate An Appendix to the Class Certificate will be issued stating assumptions for the assignment of class and restrictions regarding the use of the vessel which were established or assumed at the time of assignment of class. The “Appendix to classification certificate” shall be on board all vessels built to DNV GL's class. The appendix contains information on: 1) class notations and register information 2) general and special assumptions related to the particular ship, which may include reference to operational instructions. 4 Additional declarations Upon request, declarations confirming compliance with the rules may be issued for hull, machinery or specific class notations provided the Society's main class has been assigned. 5 Statutory certificates The Society undertakes statutory certification on behalf of flag administrations when and to the extent the Society has been authorized to do so by the individual flag administration. Statutory certification includes inter alia approval, survey and the issuance of statutory certificates. When the Society acts on behalf of a flag administration, the Society follows international statutory instruments, IACS Unified Interpretations and DNV GL Statutory interpretations, and generally follows guidance issued by IMO in circulars etc. unless the flag administration has instructed the Society otherwise. It is assumed by the Society that required statutory surveys for vessels classed by the Society will be carried out by the Society or by officers of the flag administration itself and that statutory certificates will be issued by the Society or by the flag administration with the exceptions mentioned in the paragraphs below. The Society assumes the right to withdraw class if statutory certificates are not issued as described in this paragraph. The Society may accept that safety management certificates (ISM Code) are issued by a third party that has been authorized by the flag administration and complies with IMO Resolution A.739(18) and A.789(19). The Society may accept that international ship security certificates (ISPS Code) are issued by a third party that has been authorized by the flag administration and complies with MSC/Circ.1074. The Society may accept that cargo ship safety radio certificates (SOLAS) are issued by a third party that has been authorized by the flag administration. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 100 Chapter 7 Section 5 SECTION 5 DELIVERABLES Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 101 Chapter 7 Section 5 For a dual classed vessel, where the Society has not been authorized by the flag administration to issue statutory certificates, the Society may accept that such certificates are issued by the dual class society provided the other class society is authorized by the flag administration. SECTION 1 INTRODUCTION 1 Introduction This part gives an overview of the survey and inspection of class during the operational phase, focusing on the specific aspects affecting the safety and reliability of a self-elevating unit in operation. For a complete understanding of this chapter is referred to the Rules for Drilling and support units and the standards and recommended practices as listed in Table 1. Table 1 Overview of applicable standards Reference Title DNVGL-RU-OU-0101 Offshore drilling and support units DNVGL-OS-C101 Design of offshore steel structures, general (LRFD method) DNVGL-OS-C104 Structural design of self-elevating units (LRFD method) DNVGL-OS-C201 Structural design of offshore units (WSD method) DNVGL-RP-C203 Fatigue design of offshore steel structures DNVGL-RP-C301 Design, fabrication, operation and qualification of bonded repair of steel structures DNVGL-RP-C302 Risk based corrosion management DNVGL-RP-0001 Probabilistic methods for planning of inspection for fatigue cracks in offshore structures 2 Objective The objective of the classification in operation is to confirm that the vessel, machinery installations and equipment are maintained at a standard complying with the requirements of the rules and by that has an adequate level of safety and quality. 3 Scope The technical scope of the class in operation follows the scope as discussed in Ch.4 Sec.1 [2]. Additional details describing the scope of involvement of class in operation are given in Sec.2 [2] of this part. Inspections for statutory certification are only performed if DNV GL is authorized to act on the behalf of the national authorities on their behalf. This part does not include inspection details for these statutory surveys. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 102 Chapter 8 Section 1 CHAPTER 8 CLASSIFICATION IN OPERATION 1 Conditions for retention of class The general conditions for the retention of class are given in Rules for drilling units (ref. DNVGL-RU-OU0101) Ch.1 Sec.5. Table 1 Conditions for the retention of class Description Reference in DNVGL-RU-OU-0101 Ch.1 Sec.5 General requirements [1.1] The customer’s obligations [1.2] Class society involvement [2], see Sec.2 below for further details Endorsement and renewal of Class [3] Suspension and withdrawal of Class [4] Change of Owner or Manager [5] Force Majeure [6] 2 Class involvement 2.1 General The involvement of class in operation is detailed in Rules for drilling units Ch.1 Sec.5. Table 2 Involvement of class in operation Description Reference in DNVGL-RU-OU-0101 Ch.1 Sec.5 Applicable rules [2.1] Surveys [2.2] Conditions and Memoranda [2.3] Survey reports and survey status [2.4] Damage and repairs [2.5], see below Conversion and alterations [2.6] Temporary equipment [2.7], see below 2.2 Damage and repairs Excursions from the units design envelope e.g. punch through or rack phase difference, shall be reported. Repairs to the hull structure, machinery, systems or equipment covered by the rules shall be carried out by qualified personnel and in compliance with applicable rules, with good engineering practice and under the supervision of a surveyor. Repairs as may be carried out without the attendance of a surveyor (e.g. during voyage) provided a repair plan is accepted by the Society in advance. A surveyor shall be called for acceptance of such repairs when completed. 2.3 Temporary equipment The Society shall be informed before the installation of temporary equipment as defined in Ch.1 Sec.5 [2]. Temporary equipment covered by class scope shall be approved and certified in line with normal class procedures as described in the previous parts. For temporary equipment outside class scope, it shall be confirmed that placement of this equipment on board does not negatively affect the safety of the unit. Guidance note: The following is typically considered: — escape ways shall not been blocked — fire and gas system covers the temporary equipment Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 103 Chapter 8 Section 2 SECTION 2 GENERAL PROVISIONS AND REQUIREMENTS FOR SURVEYS equipment is covered by the ESD logic — equipment’s load is within deck load limits — definition of hazardous areas takes into account the temp. equipment — interface to other systems covered by main class does not negatively affect their availability. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 3 Special provisions for ageing units 3.1 General Self-elevating units with age exceeding their initial design life (in many cases 20 years) shall be subject to evaluation for special provisions for maintaining required safety level. The special provisions are related to fatigue and corrosion condition of the hull and supporting structure and are described in the remaining of this section. Degradation mechanisms due to ageing effects related to other aspects such as marine systems have also to be given due consideration by owner through maintenance, and by DNV GL surveyors through regular surveys. 3.2 Corrosion allowance In the design of Column-stabilised and Jack-up units corrosion allowance is normally not included as the structure is considered adequately protected against corrosion, e.g. by sacrificial anodes, impressed current and coating. The corrosion diminution criteria as given in DNVGL- RP-C101, shall be applied. Alternative methods may be accepted in agreement with the Society. The condition of protection coating system and minimum measurements as given in Sec.4 [3.2] shall be carried out every 5-year period. 3.3 Calculation of fatigue life The FUI is defined as the ratio between the effective operational time and the documented fatigue life. Calculation of effective operational time shall be based on recorded operations history. For the purpose of calculating the FUI, the following may be assumed: — contribution from operation in harsh environment, e.g. North Sea, North Atlantic and Canada, equals actual operating time in such environment — contribution from operation in other environments equals one third (1/3) of actual operating time in such environments — periods of lay-up and yard stay may be disregarded — contribution from transit operation. Owner shall submit FUI or historical data allowing for calculation of FUI as part of the planning process prior to renewal survey when the nominal age exceeds the documented fatigue life. The FUIs may be calculated separately and in detail for various parts of the unit such as: — leg nodes — spud cans — jackhouse — deck structure. The calculations may reflect the various degrees of bottom restraints and loading pattern resulting from the deck being fixed at various levels during the operations history of the unit. Guidance note: Based on the above calculation a condition based approach can be applied for the inspection planning. The condition based inspection planning can be based on a high level, refined, fatigue analysis as proposed in DNVGL-RP-C203. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 104 Chapter 8 Section 2 — Operation of the unit may continue when the FUI exceeds 1.0 provided the required safety level of the vessel is maintained. If no fatigue cracks have been found in a vessel prior to the FUI reaching 1.0, or if any findings have been evaluated to have insignificant influence on the fatigue capacity, no special provisions will be required until such cracks are detected. For a vessel with FUI > 1.0 and where cracks have been detected in fatigue sensitive areas, the required safety level is in general considered satisfied either — by increasing the inspection frequency (see [3.5]) or — by performing a condition based assessment for the vessel. Where a condition based assessment for the unit is performed, the procedure and method shall be approved prior to the renewal survey for the next 5-year period. A guide for condition based inspection planning is given below. Guidance note: A condition based inspection planning is performed by judging the vessel based on the actual condition rather than on age in order to maintain the required safety level. In this context a scope implementing all or parts of the following procedure can/should be performed: — Apply the results from a fatigue analysis. The detail level of the analysis will influence the results. Higher detail level reduces the uncertainties and increases the confidence in the results and hence reduces the inspection frequency. — Mapping of critical connections w.r.t. fatigue capacity, i.e. ranking of fatigue sensitive details. — Identify details to be modified/upgraded w.r.t. fatigue strength. — Determine required safety level - dependent on consequence and access for inspection. — Apply the fatigue results in a risk based analysis (RBI) including historical data from inspections/findings and inspection quality for preparing the inspection program. — Evaluate the result from inspections (findings) and/or analysis and perform modifications/improvements ensuring that the associated risks are adequately controlled. — Perform a continuous updating of the inspection plan based on inspection results. The inspection plan obtained from a condition based approach is highly dependent on the method and procedure applied; including the confidence level of the parameters considered. Less confidence increases the probability of failure (PoF) and hence the inspection frequency will increase. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- The Society will issue a MO (Memo to Owner) stating the FUI and agreed compensating measures prior to the renewal survey for the 5-year period in which the FUI exceeds 1.0. Associated plans and procedures, i.e. condition based inspection plans applying risk based approach, shall be approved by the Society. The scope of the improvement program will depend on the initial assessment and owner's plans for further use of the unit. Units which have undergone an assessment and improvement program as outlined above to the Society's satisfaction, will be surveyed based on the modified inspection program. 3.5 Additional inspections The inspections in this section applies only if: — when the FUI exceeds 1.0 (if calculated) and/or — fatigue deficiencies have been found in fatigue prone areas and — a condition based approach as discussed in section 3.2 is not considered If fatigue cracks have been found in a unit prior to the FUI reaching 1.0, and the findings are located within fatigue sensitive areas of the unit, the owner shall assess structural details in these areas at latest prior to the renewal survey for the 5-year period. Owner shall document that the corrosion protection of the unit's hull is adequate and in line with conditions assumed in original design. The corrosion protection system shall be specially surveyed. The NDE inspection scope as planned for the renewal survey - 5 year interval - shall be performed at intermediate survey- 2½ year interval. The scope for survey of jacking gears as outlined in Sec.4 [3] shall increase to 20% of jacking gear units Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 105 Chapter 8 Section 2 3.4 Follow up 4 Alternative survey arrangements Alternative survey arrangements may be accepted as an option to applicable periodical surveys for main class. Table 3 Alternative survey arrangements Name Description Reference in DNVGL-RU-OU-0101 Ch.3 Sec.7 Machinery continuous Survey arrangement based on surveys of the machinery items Machinery PMS a survey arrangement based on a planned maintenance system (PMS) [2.3] PMS RCM Survey arrangement based on review of the company management, a Reliability Centred Maintenance (RCM) analysis and the implemented maintenance system. [2.4] Offshore CM a survey arrangement based on use of an approved service supplier for execution of condition monitoring on rotating machinery and drilling equipment [2.5] Drilling equipment survey arrangements Alternative survey arrangements applicable for units with the notation DRILL with the alternatives Continuous, PMS RCM and CM [3] Structural continuous Survey arrangement whereby the survey items in the hull list established for the unit are subject to separate surveys with an interval of 5 years. [4.2] Structural Integrity Management Classification compliance based on an approved and implemented inspection system [4.3] [2.2] 5 Surveys performed by approved companies Parts of the periodical surveys may be carried out by companies approved by DNV GL. The survey parts performed by such companies are listed in the table below. Guidance note: Note that parts of the statutory surveys may be performed by approved companies as well. Examples are inspections on Fire extinguishers, Life-boat overhaul and Life-rafts. Class is only involved in these services as long as authorised by flag to perform the statutory surveys on their behalf. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Table 4 Survey parts performed by approved companies Description Reference in DNVGL-RU-OU-0101 Ch.3 Sec.8 Thickness measurements [1.2] Bottom survey afloat [1.3] General NDT [1.4] Condition monitoring [1.6] Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 106 Chapter 8 Section 2 but not less than two units per leg. PREPARATION AND PLANNING 1 Preparation The owner shall provide the necessary facilities for safe execution of surveys. Tanks and spaces shall be safe for access, i.e. gas freed, ventilated, cleaned and illuminated. For overall and close-up examination, means shall be provided to enable the surveyor to examine the structure in a safe and practical way. Guidance note: However, the ROV can be used for cathodical protection measurements and scour surveys. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Additional requirements relevant for the execution of the survey are given in Rules for drilling units Ch.3 Sec.2 as listed in the table below. Table 1 Additional requirements relevant for the execution of the survey Description Reference in DNVGL-RU-OU-0101 Ch.3 Sec.2 Conditions for survey and access to structures [2.1] Survey extent [2.2] Repair of structural damage or deterioration [2.3] Maintenance and preparation for survey [3.1] Replacement of machinery components [3.2] Machinery certification [3.3] 2 Planning 2.1 General All units shall be subjected to periodical and specific surveys in order to confirm that the hull, machinery, equipment and systems remain in satisfactory condition and in compliance with approval or accepted standards. 2.2 Periodical surveys Periodical surveys will belong to one of the following categories according to the level of survey requirements: — annual survey — intermediate survey — complete survey. The survey required in conjunction with issuance of a new class certificate is denoted renewal survey. Specific details regarding the definition of the surveys are given in Rules for drilling units Ch.3 Sec.1 as listed in the table below. Table 2 Periodical surveys Description Reference in DNVGL-RU-OU-0101 Ch.3 Sec.1 General [2.1] Postponement of periodical surveys [2.2] Survey of units out of commissioning [2.3] Survey schedules [2.4] The periodical survey covers systems and parts for: — structure and equipment1) — machinery and safety systems2) Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 107 Chapter 8 Section 3 SECTION 3 1) Excluding outside bottom, spudcan and underwater part of legs as covered by specific surveys (See also Sec.5) 2) Adjusted depending on the followed alternative survey schemes (See also Sec.2 [4]). Specific details on the extent are specified in the in-service inspection programme as discussed in [2.4] and the following chapters The surveys may be performed on location and without interrupting the function of the unit, provided that they are based on approved procedures outlined in a maintenance system and survey arrangement. 2.3 Specific surveys Besides the standard periodical surveys, the following specific surveys are defined: — Bottom survey (covering external hull) — Spudcan-leg survey (covering spudcans and the underwater areas of legs, together with their connections) — Survey after ocean transit — Surveys in relation to permanent installation. The bottom survey and spudcan and leg survey shall both be taken two times in any five (5) year period, with an interval not exceeding three (3) years between examinations. The execution of each these surveys is mutually independent and may be aligned with the unit’s operation. Guidance note: It is noted that a bottom survey is easy to perform in operating/ elevated condition, while the spudcan and leg survey is easy to perform during a dry tow. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Consideration may be given at the discretion of the Society and with acceptance of the flag to any special circumstances justifying an extension of the interval. Guidance note: An example of such a consideration is the spud can and lower leg partly or completely under the mud line. In such a case the spud can- leg survey may be postponed to the next rig move (See IACS UR Z15 2.3.3). ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Specific surveys are discussed in detail in Sec.5. 2.4 In-service inspection program (IIP) DNV GL will develop and maintain an In-service Inspection Program (IIP) which will contain the structural items to be surveyed to satisfy the requirements of main class, excluding any additional class notations. The IIP constitutes the formal basis for surveying structural items under main class and shall be completed to the satisfaction of attending surveyor before renewal survey can be credited. The In-service Inspection Program (IIP) is developed on the basis of a general, experience-based scope in combination with design and fabrication particulars for the actual unit as well as experience from in-service surveys of units of similar type. The basic scope for development of IIP for units of self-elevating type is as given in Table 3. The extent of examination specified may be modified based on design documentation evaluation, inspection results / crack history and experience with similar units /details and may be refined by use of Risk Based Inspection (RBI) and/or Resistant Corrosion Monitoring (RCM) methodologies. Guidance note: At the 1st Annual or intermediate survey after construction, column-stabilised and self-elevating units may be subject to examination of major structural components including non-destructive testing, as deemed necessary by the Society. If the Society deems such survey to be necessary, the extent should be agreed to by the Society and the owner or client prior to commencement of the Survey. For further guidance on RBI see also DNVGL-RP-0001 Probabilistic methods for planning of inspection for fatigue cracks in offshore structures and DNVGL-RP-C302 Risk Based Corrosion Management. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 108 Chapter 8 Section 3 — temporary equipment as defined in Pt. Ch.1 Sec.5. TYPE OF SURVEY AS (see IACS z15 3.3.5 INT V Special Areas for Inspection (SP) – connections: SP1 IS EXT NDT V NDT RS INT V NDT EXT V NDT EXT V NDT V NDT A A A A A 3, 9) 1) Leg to Spudcan6) A SP2 Leg Nodes and splices above the waterline X A SP3 Connections of primary members in Jack House A A Leg guides (IACS Z15 3.3.6) X A SP4 INT Main Barge girder/bulkhead connections X X X X A A X Plating in way of leg well (IACS Z15 3.3.6) A X A A A X A Attachments of: SP5 Crane/gangway pedestals and top flange SP6 Support of Drill Floor and Cantilever SP7 Windlass and Anchor chain/wire fairleads A A A X A C A X A A A B C A A A A A A C 8) SP8 Helideck support X X X C A X A C SP9 Other attachment/support connections, e.g. flare and life boat support structures. X X X X A X A X Primary Areas for Inspection (PR): PR1 Spudcans PR2 Legs 2) X A A A A A A7) A A A PR3 Jack Houses PR4 Main Barge (deck structure) girders/bulkheads X A PR5 Drill floor with substructure and cantilever X X X X A A PR6 Crane/gangway pedestal X A A A A A X Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS A Page 109 Chapter 8 Section 3 Table 3 Basic scope for development of IIP for self-elevating units TYPE OF SURVEY AS (see IACS z15 3.3.5 INT V IS EXT NDT V NDT RS INT V NDT A EXT V NDT INT V A NDT EXT V PR7 Lifeboat platform structure PR8 Helideck and flare support structure X X X A A A PR9 Other support structures X X X X A A NDT A A = 100% 5) B = 50% 4) C = 25% 4) X = Spot check 2-5% 4) V = Visual Inspection including Close Visual Inspection of Special Areas. NDT = Non-destructive Testing, normally Magnetic Particle Inspection (MPI) and/or Eddy Current (ET) of selected stress concentrations and fatigue sensitive details. 1) Special Areas for Inspection (SP) are those sections of the structure which are in way of critical load transfer point, stress concentrations, often special steel selection etc. see listing in Sec.4 [1.1] 2) Primary Areas for Inspection (PR) are elements which are essential to the overall structural integrity of the unit. See listing in Sec.4 [1.1] 3) At levels which have been in way of lower guided in operation, upper guides in transit and in way of spudcans. 4) - of the total number of these parts. 5) The inspection extent might be reduced (be less than 100%) if based on design documentation, see [1.2.6] (above). 6) As part of the ‘lower leg & spudcan’ survey as defined in Sec.5 7) For plate type legs, square or circular. examine also the pin holes IACS Z15 2.3.3). 8) May be waived if unit permanently operating on the field. 9) Only for leg nodes above the waterline. Leg nodes below the waterline are part of the ‘lower leg & spudcan’ survey. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 110 Chapter 8 Section 3 Table 3 Basic scope for development of IIP for self-elevating units (Continued) 1 Annual survey 1.1 Structure and equipment 1.1.1 Hull Condition of protective coating to be reported on according Table 1. Table 1 Conditions of protective coating Corrosion protection system Normally a full hard coating, usually to be epoxy coating or equivalent. Other coating systems, which are neither soft nor semi-hard coatings, may be accepted provided they are applied and maintained in compliance with the manufacturer's specification. (See IACS UR Z7) However, soft and semi hard coatings, if already applied, may be accepted as result of a condition based assessment including a review of the organizational set-up to maintain adequate corrosion protection. Coating condition “GOOD” Condition with only minor spot rusting. Coating condition “FAIR” Condition with local breakdown at edges of stiffeners and weld connections and/or light rusting over 20% or more of areas under consideration, but less than as defined for POOR condition. Coating condition “POOR” Condition with general breakdown of coating over 20% or more of areas or hard scale at 10% or more of areas under consideration. For areas with general breakdown of the protective coating, close-up examination and thickness measurements shall be carried out to an extent sufficient to determine both general and local corrosion levels following Table 2 as guidance. Table 2 Thickness measurements, extent and pattern in way of areas with substantial corrosion, all ships Area/ Structural Member Extent of measurement Pattern of measurement Plating Suspect area and adjacent plates 5 points over 1 m2 Stiffeners Suspect area 3 points in line across web 3 points in line across flange Ref: IACS UR Z7 Table II 1.1.2 Watertight/ weathertight integrity Items which are important for the reserve buoyancy in connection with stability of the unit shall be surveyed. The survey shall include inspection of external and internal closing appliances, ventilators, air pipes, side scuttles etc., as well as an external inspection of scupper valves and sanitary valves. (See IACS UR Z15 3.3.3) Remote controls and alarm systems for doors, hatches and watertight dampers shall be surveyed and function tested. Guard rails shall be examined. Guidance note: For units or installations subjected to annual load line inspections by DNV GL, the requirements in this sub section are considered covered by this inspection. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 1.1.3 Towing system Accessible and visible parts of the unit's permanent towing arrangement shall be inspected 1.1.4 Deck houses and means of escape Deck houses accommodating crew shall be surveyed. (see IACS Z15 3.3.3) Means of escape from working and accommodation spaces to muster location, helideck and lifeboat Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 111 Chapter 8 Section 4 SECTION 4 PERIODICAL SURVEYS 1.2 Machinery and safety systems 1.2.1 Machinery The survey shall include examination of spaces for machinery, boilers and incinerators, and equipment located therein, with particular attention to fire and explosion hazards. As the DNV GL surveyor deems necessary, running tests and/or opening of machinery, tests of safety devices and equipment with verification of integrity/ function of: — jacketed high pressure fuel injection piping system — shielding of flammable oil piping system — insulation of hot surfaces exceeding 220ºC — oil burning equipment on boilers, hot water heaters, incinerators and inert gas generators. Remote shutdown for fuel-oil transfer service pumps and ventilating equipment, together with oil tank outlet valves where required to be capable of being remotely closed shall be proved satisfactory (quick closing valves). (ref. IACS UR Z15, 2.8,2) Boilers shall be externally surveyed. The general condition of the boiler including mountings, piping and insulation shall be ascertained and the surveyor may require opening, removal of insulation etc. if found necessary. Safety valves, instrumentation and automation systems shall be tested in operating condition when found necessary by the surveyor. Helifuel systems shall be surveyed with particular attention to general cleanliness and maintenance with special attention to fire/explosion hazards. 1.2.2 Jacking system The brake torques of jacking machinery on self-elevating units shall be checked. Where provided, the fixation rack system shall also be checked. Spot check on oil sample records. A visual examination of the hydraulic lifting system shall be carried out, where applicable. (See IACS Z15 3.3.5) 1.2.3 Hazardous area In hazardous areas the following equipment and systems shall be surveyed or tested: — ventilation systems shall be function tested. The tests shall include emergency stop systems and alarms for lost ventilation — self-closing gastight doors and airlocks including other openings or accesses — alarms and shutdown functions for pressurised equipment shall be function tested — gas detection equipment shall be function tested — electrical equipment shall be visually inspectedwith respect to general condition and spark/explosion hazard — devices for monitoring of insulation resistance or earth leak monitoring including alarms — protection devices for combustion engines. (See IACS Z15 3.5 and 3.7) 1.2.4 Temporary equipment Temporary equipment as defined in Sec.1 [1] shall be surveyed. 1.2.5 Fire and gas systems For fire extinguishing systems the survey shall include: — testing of the water fire fighting system i.e. fire pumps, fire mains, hydrants and hoses as deemed Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 112 Chapter 8 Section 4 embarkation deck shall be verified in order. Chapter 8 Section 4 necessary — verification of the non-portable and portable fire extinguishers and portable foam applicators — examination of the fireman's outfit — examination of the fixed fire extinguishing systems. The following systems shall be surveyed and tested for correct functioning: — fire detection system — gas detection system, both flammable and toxic — general alarm system and communication between control stations. (see IACS UR Z15 3.5 and 3.7) 1.2.6 Electrical installations For electrical installations the survey shall include: — examination of main source of electrical power with respect to general condition, fire hazard and personnel safety, i.e. generators, main switchboards, distribution boards, control gear, consumers, chargers and battery/UPS systems — test of automatic start and connection to the switchboard of the stand-by generator set by initiating shutdown of the running diesel generator causing black-out. — inspection of insulation monitoring devices for all distribution systems. If in doubt of correct reading (ex. if the reading is infinity), the device shall be tested — examination of cable installations with respect to general condition, support and physical protection — examination of emergency source of electrical power with respect to general condition, fire hazard, personnel safety and function, i.e. generator, emergency switchboard, emergency distribution boards, control gear, chargers, emergency consumers and battery/ UPS systems — check if any modifications are done in the electrical system — test of emergency power system, i.e. manual and automatic connection of generator/batteries to emergency switchboards, alternative start methods. — it shall be verified that records of inspections and maintenance of Ex- installations in accordance with the implemented maintenance system are kept available onboard. — verify that the document “Schedule of batteries” is kept up to date. 1.2.7 Control and monitoring systems Control and monitoring systems for auxiliary machinery shall be surveyed including: — electric power generation and distribution — steam generation — thermal oil heating — oil or gas burning equipment on incinerators, inert gas generators and hot water heaters. The survey shall include: — alarm functions — safety functions — remote control functions — automatic control functions — electrical and mechanical condition, labels, signboards etc. — control panels and local indicating instruments — emergency lighting in engine room — communication systems — fire alarm and fire protection systems. — verification of the change handling process for control and monitoring systems, see DNVGL-OS-D202, Ch.2 Sec. 3. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 113 Guidance note: If operations make it difficult to carry out testing, a low level ESD is sufficient to comply to the above. As an alternative, a review of ESD test records can be done. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 1.2.9 Bilge system The bilge system and related subsystems shall be visually surveyed and tested. 1.2.10 Loading instruments If a loading instrument or loading computer system is available onboard it shall be verified that the system has a valid certificate. It shall be documented that an annual check of the loading instrument/computer by running one of the test conditions has been carried out. If not, the surveyor shall verify the running of the test condition onboard. 1.3 Documentation The «Appendix to the classification certificate» and the documents referred to therein, shall be verified as kept available onboard the unit. Any changes to the systems (new equipment and overhauls, repairs and modifications) shall be surveyed and the relevant documentation to be reviewed. (See IACS Z15 3.3.2) The system for recording changes to the lightweight of the unit shall be surveyed. The system for tank level measurement shall be surveyed, with regard to accuracy, operability and redundancy. Approved loading and stability information shall be verified available onboard. This information shall be the same as required when the unit was assigned class with the Society or at a later conversion of the unit, in accordance with the rule requirements applicable in each case. It shall be confirmed that the unit is operating within its approved design envelope. For units that shall comply with SOLAS Reg. IX/2, irrespective of the issuing authority for the Safety Management Certificate (SMC), the surveyor will complete a list of evidence of possible safety management system failures recorded on the occasion of the annual survey. The list will be submitted with the annual survey report. For units granted a survey arrangement based on an approved planned maintenance system (PMS), an annual survey of the PMS is required to prolong the validity of the arrangement. The purpose of this survey is to review and evaluate the previous period's maintenance activities and experience. The annual survey shall consist of the following main elements: a) The maintenance history will be examined in order to verify that the PMS has been operated according to the intentions and that the system is kept up to date. b) Evaluation of the maintenance history for main overhaul jobs on the components covered by the continuous machinery survey (CMS) scheme carried out since last annual survey. c) Details of corrective actions on components in the CMS scheme shall be made available. d) If condition monitoring equipment is in use, function tests of this equipment and verification of the calibration will be carried out as far as practicable and reasonable. 2 Intermediate survey 2.1 Structure and equipment 2.1.1 General The survey shall, in general, be carried out as the annual survey, but with extended visual inspection and Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 114 Chapter 8 Section 4 1.2.8 ESD Emergency shutdown facilities shall be surveyed and tested. 2.1.2 Tanks For rigs over 5 years, at least two representative hull pre-load tanks shall be inspected. (See IACS UR Z1, 4.3.3). For units over 10 years of age the survey of sewage (black water) tanks and wastewater (grey water) tanks shall include: — for integral tanks internal examination. — Tanks with hard coating of internal structures recorded in GOOD condition at the previous renewal survey may be specially considered based on a satisfactory external examination.The internal examination of tanks used in association with sewage treatment may be specially considered based on a satisfactory external examination and provided that an internal inspection has been carried out in accordance with onboard maintenance system during the last 12 months and relevant records are provided and confirmed. — for independent tanks external examination including the tank supporting structures. — thickness measurements shall be carried out as deemed necessary. 2.1.3 Legs Survey of the upper part of the legs is normally required as specified in IIP. Potential measurements will also be required if found necessary. See Sec.5 for the inspection of the underwater part of the legs. 2.2 Machinery and systems As per annual (See Sec.4 [1.2]). 3 Renewal survey 3.1 Extent The extent of the survey includes the requirements of the annual and intermediate survey, the items as given in the in-service inspection program as given in Sec.3 [2.4], and additionally the requirements as discussed in this chapter. Deficiencies shall normally be rectified before the renewal survey is regarded as completed. The Society may accept that minor deficiencies, recorded as condition of class, are rectified within a specified time limit, normally not exceeding 3 months after the survey completion date. For units intended to stay on location for prolonged periods, see Sec.6. 3.2 Structure and equipment 3.2.1 Thickness measurements Thickness measurements shall in general be carried out as presented in Table 3. Areas where substantial corrosion is found at the survey being carried out, shall have thickness measurements extended following Table 2. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 115 Chapter 8 Section 4 non-destructive testing of the structure as given in the in-service inspection programme (See Sec.3 [2.4]). Id. Area Renewal survey No.1 Age 0-5 years Renewal survey No.2 Age 5-10 years Renewal survey No.3 Age 10-15 years Renewal survey No.4 and subsequent Age >15 years 1 All Suspect areas Suspect areas Suspect areas Suspect areas 2 Structural components of Special and Primary category Areas with indication of wastage Areas with indication of wastage Areas with indication of wastage Areas with indication of wastage 3 Legs Representative chords and bracings/ plate and stiffeners in way of splash zone Representative chords and bracings/ plate and stiffeners in way of splash zone and at connections to mat/ spudcan Representative chords and bracings/ plate and stiffeners in way of splash zone and at connections to mat/ spudcan. Representative chords and bracings/ plate and stiffeners in other levels 4 Mat or spudcan connections to legs and main structural bulkheads of mat or spudcan Representative plates, bulkheads and stiffeners All plates, bulkheads Representative plates, bulkheads and and stiffeners stiffeners 5 Jackhouse and load transfer area (external and in way of preload tanks) including leg wells and lower guides Representative plates and stiffeners Representative plates All plates and stiffeners and stiffeners 6 Upper Hull exposed deck and bottom plating Representative plates Representative plates All plates 7 Upper hull “Box” or “I” type sections Main supporting structure 8 Preload tanks 9 Representative plates Representative plates and stiffeners and stiffeners Representative structure of two preload (seawater) tanks Representative structure of all preload (seawater) tanks Main supporting structure of heavy substructures and equipment. e.g. crane pedestal, cantilever and drill floor substructure, lifeboat platform and helicopter deck Representative plating and stiffeners Representative plating and stiffeners 10 Structural components of Special or Primary category other than under 3 to 7 above. (These areas are normally identified in the IIP) Representative plating and stiffeners Representative plating and stiffeners 11 Air pipes and ventilators Selected air pipes and All air pipes and ventilator coamings on ventilator coamings exposed main deck on exposed main deck 12 Plating of sea chest. Representative structure of one preload (seawater) tank All plating of sea chest Notes: 1) and 2) if considered necessary by the attending surveyor. 3) to 12) mandatory thickness measurements, number and extent of thickness measurement requirements may be modified by the surveyor considering the corrosion protection condition and arrangements. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 116 Chapter 8 Section 4 Table 3 Minimum requirements for thickness measurements - self elevating units — Areas of legs without an efficient/intact hard epoxy coating system in way of the splash zone. — Upper hull seawater tanks without an efficient/intact hard epoxy coating system. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- Application categories for structural components to be inspected referred in the table above, are defined in Sec.3 Table 3. Special areas for Inspection: Vertical columns in way of intersection with the mat structure (spudcan). Highly stressed elements of bottom of leg, including leg connection to spudcan or mat. Intersections of lattice type leg structure, which incorporates novel construction, including the use of steel castings. Highly stressed elements of guide structures, jacking and locking system(s), jackhouse and support structure. Highly stressed elements of crane pedestals, etc. and their supporting structure. Primary areas for Inspection: Combination of bulkhead, deck, side and bottom plating within the hull which form “Box” or “I” type main supporting structure. All components of lattice type legs and external plating of cylindrical legs. Jackhouse supporting structure and bottom footing structure, which receives initial transfer of load from legs. Internal bulkheads, shell and deck of spudcan or bottom mat supporting structures which are designed to distribute major loads, either uniform or concentrated, into the mat structure. Main support structure of heavy substructures and equipment, e.g. cranes, drill floor substructure, life boat platform and helicopter deck. Other areas for Inspection: Deck, side and bottom plating of hull except areas where the structure is considered primary or special application. Bulkheads, stiffeners, decks and girders in hull that are not considered as primary or special application. Internal bulkheads and girders in cylindrical legs. Internal bulkheads, stiffeners and girders of spudcan or bottom mat supporting structures except where the structures are considered primary or special areas for inspection. In addition to the above, spot checks may be taken in other areas in order to assess the general condition of the unit. Guidance note: Recommended locations for the spot checks are the main deck (often problem area due to frequent deck loading/unloading) and preload tanks. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 3.2.2 Tanks Where wastage is evident or suspect, thickness measurements shall be carried out. An internal overall examination of all spaces, except fuel oil, lube oil and fresh water tanks, shall include all structures, piping systems outside machinery area and sea connections in machinery area, i.e. plating and framing, bilges and drain wells, sounding, venting, pumping and drainage arrangements. The tightness of the tanks shall be verified with a head of liquid to the overflow or by an appropriate procedure. (see IACS Z15 2.3.1) Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 117 Chapter 8 Section 4 Guidance note: Sample of structures prone to rapid wastage; — For integral tanks internal examination. For units not exceeding 10 years of age the internal examination of tanks used in association with sewage treatment may be specially considered based on a satisfactory external examination and provided that an internal inspection has been carried out in accordance with onboard maintenance system during the last 12 months and relevant records are provided and confirmed. — For independent tanks external examination including the tank supporting structures. Thickness measurements shall be carried out as deemed necessary. Where provided, the condition of the corrosion prevention system of cargo oil tanks shall be examined. Examination of fuel oil, lube oil and fresh water tanks shall be in accordance with Table 4. Independent tanks in machinery spaces shall be externally examined including the tank supporting structures. Table 4 Minimum requirements for internal examination of fuel oil, lube oil and fresh water tanks Tank 1) 2) 3) Age of ship, years 0 to 5 5 to 10 10 to 15 above 15 Engine room/machinery space None None Area outside engine room/machinery space None One Lube oil None None None One None One All All Fuel oil/ diesel oil Fresh water 5) One Two 4) One Half, minimum two 4) Notes: 1) Tanks of integral (structural) type. 2) If a selection of tanks are accepted to be examined, then different tanks shall, as far as practicable, be examined at each renewal survey, on a rotational basis. 3) Peak tanks (all uses) are subject to internal examination at each renewal survey. 4) At renewal surveys no 3 and subsequent surveys, one deep tank for fuel oil outside engine room shall be included, if fitted. 5) Tanks for clean fresh water, i.e. potable water, boiler water and other holding tanks for clean fresh water. Tanks for mainly contaminated fresh water as waste water (grey water) and sewage (black water) shall be subject to internal examination as given above. (see IACS UR Z7) 3.2.3 Watertight integrity The watertight integrity of internal bulkheads and decks shall be verified. Special arrangements related to stability such as watertight closing appliances for openings in internal bulkheads and decks, cross-flooding, counter-flooding etc., shall be examined and tested if necessary. Bulkhead shaft seals shall be verified. Dismantling shall be carried out where necessary to examine condition of the bulkhead seal. Guidance note: Documented maintenance may be considered as a base for extent of dismantling. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 3.2.4 Testing of Structures and tanks Testing of structures forming boundaries of double bottom, deep tanks, peak tanks and other tanks, including holds adapted for the carriage of water ballast, shall be in accordance with Table 3-6. The surveyor may require further testing. Testing of other spaces not designed for the carriage of liquid may be omitted, provided a satisfactory internal examination together with an examination of the tanktop is carried out. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 118 Chapter 8 Section 4 For sewage (black water) tanks and wastewater (grey water) tanks the survey shall include: Table 5 Minimum requirements for testing of tanks Tanks 1) to be tested Ballast tanks Test head or pressure Remark Top of air pipe Cargo holds adapted for carriage Near the top of cargo hold hatch coaming of ballast 3) Bilge water holding tanks Top of air pipe 2) alternatively as for fuel oil tanks Fuel oil tanks Head of liquid to the highest point that liquid will rise under service conditions 2), 3) Lub. Oil tanks Head of liquid to the highest point that liquid will rise under service conditions 2) Fresh water tanks Head of liquid to the highest point that liquid will rise under service conditions 2), 3) Sewage (black and grey water) tanks Top of air pipe As deemed necessary by the surveyor Tanks containing other liquids Head of liquid to the highest point that liquid will rise under service conditions As deemed necessary by the surveyor Notes: 1) 2) 3) Gravity tanks of integral type Tanks within machinery spaces may be specially considered based on external examination of the tank boundaries and a confirmation from the Master stating that no leakages or other defects have been observed during operation of the vessel. Tanks within the cargo area may be specially considered based on a satisfactory external examination of the tank boundaries and a confirmation from the Master stating that the pressure testing has been carried out according to the requirements with satisfactory results. Remote level indicating systems for ballast tanks shall be surveyed and function tested. 3.2.5 Air pipe heads Air pipe heads on exposed decks shall be externally and internally examined following Table 6 below. According to the results of the examination, the surveyor may require examination of other air pipe heads. Table 6 Examination of air pipes 1st renewal survey 2nd renewal survey 3rd renewal survey Four randomly chosen, preferably serving ballast tanks 25% of all the air pipes randomly chosen all air pipe heads.Exemption may be considered for air pipe heads where there is substantiated evidence of replacement within the previous five years. 3.2.6 Piping systems Jetting piping systems or other external piping, particularly where penetrating mats or spud cans. (IACS UR Z15 2.3.3.) 3.2.7 Towing equipment The permanent towing arrangement of the unit shall be surveyed. Towing equipment is subject to visual inspection. 3.2.8 Major appurtenances Fixation of major appurtenances to the main structure shall be surveyed. These may typically include crane pedestals, helicopter decks, drilling derricks, lifeboat platforms and heavy deck modules or skids. 3.3 Machinery and systems 3.3.1 Machinery Settling tank and daily service tanks for heavy fuel oil and diesel oil as well as lubrication oil circulation tanks assessed with respect to tank cleanliness. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 119 Chapter 8 Section 4 Independent tanks in machinery spaces shall be tested as deemed necessary. Opening up of tanks may be required as found necessary by the surveyor. 3.3.2 Electrical installations The survey shall comprise examination of the electrical installations with regard to fire and explosion hazards and injury from accidental touching. The survey is also to include testing of correct functioning of equipment covered by class requirements. As far as practicable, the following equipment shall be examined for satisfactory condition: — main and emergency switchboards — generators — distribution boards — motor starters — electrical motors — converters (e.g. transformers, rectifiers, chargers) — cable installations — enclosures for electrical equipment — lighting equipment — heating equipment — battery installations. The following tests shall be carried out to the extent deemed necessary by the surveyor to ascertain the proper functioning of the equipment: — generator full load test; minimum load for life support and emergency jacking should be guaranteed — generator parallel operation — generator protection relays including non-important load trip, if fitted — generator remote speed control — generator synchronising equipment — power plant interlocking systems — insulation resistance indicating device — emergency generator including switchboards; auto start following loss of main supply — battery chargers — mechanical ventilation of battery rooms and lockers — electrical motors for essential and important use, e.g. for jacking system at full load — interlocking and/or alarms for pressurised rooms and equipment. — air systems and their redundancy as part of safety- or important systems. Protection relays in generator and bus tie circuit breakers shall be tested with secondary current injection, or with suitable apparatus made for testing of the installed protection units. Records of insulation test shall be shown to the surveyor. This requirement may be waived if: — testing of all individual motors is included and logged in the planned maintenance system, and — the insulation monitoring alarms required by DNVGL-OS-D202 Ch.2 Sec.2 are integrated in the machinery alarm 3.3.3 Jacking system The jacking systems, including shock pads, shall be examined in the presence of the Surveyor by the original equipment manufacturer or other third party inspector mutually agreeable to the owner and the Surveyor. A selected number of jacking gear units (about 20%, but not less than one unit per leg) shall be opened up for inspection. Oil analysis shall be presented for all the jacking gear units. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 120 Chapter 8 Section 4 If inspection and cleaning have been carried out by the crew during the last 12 months and relevant log extracts are provided and confirmed, this may be credited as surveyed at the surveyor's discretion. a) Racks and climbing pinions (visual examination for wear and proper tooth contact) b) Planetary gear boxes (opening and visual examination of at least one per leg, oil analyses for all) (see Guidance note). c) Linear gearboxes (can be inspected by means of endoscope or inspection covers when provided) d) Braking systems (opening and visual examination of at least one per leg) e) Pinions (pinion clearance if accessible). f) Survey and NDT of jacking guides to the extent possible to be included. g) Oil samples shall be collected directly after a jacking operation to ensure representative values Guidance note: The above is specific for rack-pinion types of jacking systems. Alternative systems should have a comparable level of inspection making sure the system is safe to operate for the next 5 year. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- For units with hydraulic cylinders for lifting the working and holding pins shall be examined by NDT. The working and holding yokes shall be tested for cracks by NDT. For self-elevating units, all parts of the legs shall be examined. 3.3.4 Raw water pumps Check availability of water supply for safety systems, i.e fire water for different operational conditions (transit, during jacking and in elevated conditions). 3.3.5 Hazardous area Enclosed hazardous areas such as those containing open active mud tanks, shale shakers, de-gassers and de-sanders shall be examined and doors and closures in boundary bulkheads verified as effective. Ventilating systems including ductwork, fans, intake, exhaust locations for enclosed restricted areas and alarm system shall be examined, tested and proven satisfactory. Electrical equipment in hazardous areas shall be examined with respect to: — corrosion — flameproof enclosure/ingress — no unauthorised modification — correct rating of lamps — earthing (spot check) — function testing of pressurised equipment and of associated alarms — testing of insulation resistance of power circuits (Ex p, Ex e and Ex n). Where proper records of testing are maintained consideration may be given to accepting recent readings (maximum 12 months) by the ship's crew — insulation monitors with alarms shall be function tested, if installed — for rooms protected by air locks, interlocking with ventilation of electrical supply to non-explosion protected equipment and de-energising of such equipment in case of ventilation failure shall be examined and function tested as applicable. Guidance note: Megger testing may involve risk of explosion due to sparks. Therefore appropriate procedures for such work should be followed as relevant e.g., “gas free certificate”. Ex equipment to include Ex motors and Ex junction boxes and Ex enclosures. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 3.3.6 Fire protection/ extinguishing/ prevention Correct functioning of the various parts of the following systems shall, as far as applicable, be verified: — alarm and safety system — fire and gas detection systems. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 121 Chapter 8 Section 4 The inspection shall include the following: Emergency switch(es) for all electrical equipment including main and emergency generators, except alarm and communication systems and lighting in vital areas such as escape routes and landing platforms, shall be proved satisfactory (by a combination of testing and review of maintenance records). (see IACS UR Z15, 2.8.2) Guidance note: The above implies a complete test of the ESD system in the presence of DNV GL. Approved Cause and effect Diagrams should be available if possible. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 3.4 General The presence of required signboards shall be verified. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 122 Chapter 8 Section 4 3.3.7 Instrumentation and automation When cancelling of automatic load reduction and/or automatic stop of engine are provided, these functions shall be demonstrated to the surveyor. 1 Record keeping Plans and procedures for underwater inspection shall be submitted for review in advance of the survey and made available on board. Submitted data, after review by the Society, will be subject to revision if found to be necessary in light of experience. Guidance note: The Society may consider alternative methods for providing adequate assurance that a unit's bottom is in a satisfactory condition at the mid-term class period survey. A survey based on such alternative methods is subject to acceptance by the relevant flag administration. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 2 Bottom survey For the interval of the bottom survey see Ch.8 Sec.3 [2.3]. The bottom survey afloat may replace the statutory dry docked survey provided acceptance from the flag. Underwater inspection in lieu of drydocking survey may not be acceptable where there is record of abnormal deterioration or damage to the underwater structure; or where damage affecting the fitness of the unit is found during the course of the survey. Valves are checked for proper condition / closing and operation, often fitted with remote operation by means of rod extensions etc. Sea chests and other sea inlets and discharges (above and below the waterline) with valves, including sanitary valves and scupper valves, shall be opened for survey. 3 Spudcan and leg survey 3.1 General For the interval of the spudcan and leg survey see Sec.3 [2.3] Considerations shall be given to safe entry and accessibility of the spudcans before the survey. Guidance note: The considerations include ventilation, arrangements for pumps, cables for lighting etc. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 3.2 Scope The spudcan and leg survey includes the leg nodes below the water line. The nodes above are inspected during the normal periodical surveys. 3.3 Inspection External surfaces of spudcans, mat, underwater areas of legs, together with their connections as applicable, shall be selectively cleaned to the satisfaction of the attending surveyor and examined. The surveyor shall be satisfied with the condition of the internal structure of the spudcans. Leg connections to spudcans shall be examined at each dry-dock survey or equivalent For rigs over 5 years, free-flooding compartments in mat or spud cans, shall be inspected. (See IACS UR Z17 4.3.3). The cathodic protection system of the submerged zone shall be surveyed. The efficiency of the system for the forthcoming 5-year period shall be confirmed. The cathodic protection system shall be surveyed by visual inspection of sacrificial anodes and extent of corrosion. Corrosion in welds of vital parts which may be subject to fatigue shall be particularly considered. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 123 Chapter 8 Section 5 SECTION 5 OTHER SURVEYS After an ocean transit, a survey shall ensure that the unit is in sound condition and did not suffer from damage from bad weather during the transit, otherwise consequences of inappropriate shimming of the legs. This post-transit survey applies both for wet and dry tows and shall be carried out before elevating the unit. The survey shall consist of the visual inspection and NDT testing with a focus on the following structural areas: — Jackhouse structure and connection to the hull, — Leg Nodes in way of upper/lower guides and chord spudcan connection. — Main deck area in way of support of gearboxes. The owner shall prepare a survey plan including details of the tow to be submitted to the Society for approval prior to commencement. The owner may perform the survey himself. If the survey reveals damage, DNV GL shall be involved in line with Sec.2 [2.2]. If no damage are found, inspection records shall be shown at the next periodical survey. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 124 Chapter 8 Section 5 4 Survey after ocean transit 1 Introduction The requirements and guidance given in this chapter are supplementary requirements for units that are intended to stay on location for prolonged periods, normally more than 5 years. Permanently installed self-elevating units shall be designed or documented for the site specific environmental and soil conditions. Fatigue properties and facilities for survey on location shall be specially considered. Adequate corrosion protection shall be implemented to cover the entire prolonged operation period. 2 Fatigue Design Fatigue Factors (DFF) are introduced as fatigue safety factors. DFF shall be applied to structural elements according to the principles in DNVGL-OS-C101. Fatigue safety factors applied for permanently installed self-elevating units shall be given dependent on the criticality of the detail and accessibility for inspection and repair. Special considerations should be made for the leg in the splash zone, submerged parts legs and spudcan, and possible inaccessible parts of the spudcan. The fatigue analysis should focus on members that are essential to the overall structural integrity of the unit. Fatigue susceptible areas may include: — the leg to hull holding system — the leg members and joints in the vicinity of the upper and lower guides — the leg members and joints in the splashing zone — the leg members and joints in the lower part of the leg near the spudcan — the spudcan to leg connection. Guidance note: See DNVGL-OS-C101 Ch.2 Sec.9 to Sec.10, and Sec.11 [2.2] with respect to vertical extent of splash zone. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 3 Inspection and maintenance 3.1 Facilities for survey Surveys may be carried out on location based on agreed procedures outlined in a maintenance system and survey arrangement, without interrupting the function of the unit. The following matters shall be taken into consideration to be able to carry out surveys on location: — arrangements and methods for survey of hull, legs and seabed foundation structure — corrosion protection of hull, legs and seabed foundation structure — underwater cleaning facilities. 3.2 Surveys Surveys for permanently installed units follow the same approach as described in the previous chapters with the following remarks: — The in service inspection program (IIP) should reflect possible stress concentrations in critical areas, fatigue criticality, and the previous operational and inspection histories. — Provided the fatigue analysis as described in Sec.1 justifies integrity during the installation period, the Spudcan and Leg survey is limited to the accessible structure above the mudline. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 125 Chapter 8 Section 6 SECTION 6 PERMANENTLY INSTALLED SELF-ELEVATING UNITS 3.3 Inspection before re-location Permanent installed units planned for a re-location shall have a survey prior to movement. The survey scope shall include the jacking system. Before re-location, an analyse shall document that the unit’s structural strength taken into account the new location’ environmental and soil conditions is sufficient for the remaining life time. A complete spudcan and leg survey as described in Sec.5 [3.3] shall be completed before re-location. Rules for classification, Offshore units DNVGL-RU-OU-0104 – Edition July 2015 Self-elevating units DNV GL AS Page 126 Chapter 8 Section 6 — Provided the unit has arrangements for a fix load transfer by a permanent fixation system, the jacking system will be excluded from survey after the initial jacking of the unit. 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