TCVN NATIONAL STANDARD

TCVN 6474-1: 2007 TCVN 6474-9: 2007 Second edition

RULES FOR CLASSIFICATION AND TECHNICAL SUPERVISION OF FLOATING STORAGE UNITS

HA NOI -2007

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NATIONAL STANDARD TCVN 6474-1: 2007 TCVN 6474-9: 2007

Foreword

National standards from TCVN 6474-1:2007 to TCVN 6474-9:2007 replace to TCVN

6474:1999.

National standards from TCVN 6474-1:2007 to TCVN 6474-9:2007 are edited by

Vietnam Register and TCVN/TC8 ''Shipbuilding and Offshore'' Technical Standard

Board, is proposed by Ministry of Transportation and Standard - Measure - Quality

General Department, is promulgated by Ministry of Science and Technology.

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NATIONAL STANDARD TCVN 6474-1: 2007 TCVN 6474-9: 2007 CONTENTS

Foreword 3

PART 1: CLASSIFICATION 25

1 General requirements 25

1.1 Application 25

1.2 Reference documents 25

2 Definition and explaination 27

2.1 Floating storage units. 27

2.1.1 Purpose 27

2.1.2 Major Elements 27

2.2 Type of floating storage units 27

2.3 Coordinates and motion 28

2.4 Production Facilities 29

2.4.1 General 29

2.4.2 Production Support Systems 29

2.4.3 Hazardous Areas 29

2.4.4 Piping and Instrumentation Diagrams (P&IDs) 30

2.4.5 Safety Analysis Function Evaluation (S.A.F.E.) Charts 30

2.5 Position Mooring System 30

2.5.1 General 30

2.5.2 Spread Mooring 30

2.5.3 Single Point Mooring (SPM) 31

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2.5.4 Dynamic Positioning and Thruster Assisted Systems 36

2.6 Subsea System 36

2.6.1 General 36

2.6.2 Floating Hose 36

2.6.3 On Bottom Flexible Flow Lines 36

2.6.4 Pipe Line End Manifold (PLEM) 36

2.6.5 Riser 36

2.6.6 Riser System 37

2.6.7 Riser Support 37

2.6.8 Submerged Jumper Hoses 37

3 Classification 38

3.1 Class assignation 38

3.2 Class of floating storage units 38

3.2.1 Scope of classification for floating storage units 38

3.2.2 Basic characters of classification for floating storage units 38

3.2.3 Class notations of hull of floating storage units 38

3.2.4 Class notations of machinery of floating storage units 39

3.3 Subdivision notation and additional notations 39

3.3.1 Subdivision notation 39

3.3.2 Notation for in water survey of submerged part of hull of floating storage units 40

3.3.3 Notation for enhanced survey programme 40

3.3.4 Notation for function of floating storage units 40

3.3.5 Dynamic positioning system 40

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3.3.6 Notations for location and operational condition 40

3.3.7 Example for charaters and notations of classification 41

3.4 Class maintenance 41

3.5 Suspension of Class 41

3.6 Lifting of Suspension 42

3.7 Withdrawal of class and chance character of classification 42

3.8 Reclassification 42

3.9 Requisition for a survey 43

3.9.1 Classification survey 43

3.9.2 Survey for class maintenance 43

3.10 Certificate of Classification 43

3.10.1 Issurance of Classification Certification 43

3.10.2 Endorsement of Classification Certificates 43

3.10.3 Issuance of Provisional Classification Certificates 43

3.10.4 Validity of Certificate of Classification and Provisional Certificate of Classification 43

3.10.5 Retention, Reissue, Rewriting and Return of Certificate of Classification 44

4 Technical documentation 46

4.1 Design documents for submission 46

4.1.1 Design documents for submission 46

4.1.2 Amendments to approved technical documentation 46

4.1.3 Submission of final design documentation 46

4.1.4 Requirements for the technical documentation for approval 46

4.1.5 Duration of validity of approved technical documentation 46

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4.2 Documents issued by VR 47

4.2.1 Documents issued in compliance with the Rules 47

4.2.2 Seaworthiness certificate 47

5 Classification Surveys 49

5.1 Classification Surveys during Construction 49

5.1.1 General 49

5.2 Submission of Plans and Documents for Approval 49

5.2.1 Hull of floating storage units 49

5.2.2 Position Mooring System 52

5.2.3 Production Facilities and Production Support Facilities 52

5.2.4 Import/export system 54

5.2.5 Machinery installations and electrical installations 55

5.2.6 Manuals and Procedures 55

5.3 Presence of Surveyor 56

5.4 Hydrostatic and Watertight tests 57

5.5 Classification Survey of Unit not built under Survey 57

5.5.1 General 57

5.5.2 Tests 58

PART 2: ENVIRONMENTAL LOADING AND DESIGN BASIC 59

1 Environmental loading and design basis 59

1.1 Design Basis 59

1.2 Design Documentation 59

1.3 Design Conditions 60

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1.3.1 Position Mooring System 60

1.3.2 Structural Strength and Fatigue Life 61

1.4 Environmental Conditions 63

1.4.1 General 63

1.4.2 Environmental Loads 64

1.4.3 Current 64

1.4.4 Wind 65

1.4.5 Waves 67

1.4.6 Directionality 69

1.4.7 Soil Conditions 69

PART 3 : TECHNICAL REQUIREMENTS 71

1 Technical requirements for floating storage units 71

1.1 All Vessels 71

1.1.1 General 71

1.1.2 Lightweight Data 72

1.1.3 Load Line 72

1.1.4 Operating Manual 72

1.1.5 Loading Manual (Operating Manual) 74

1.1.6 Trim and Stability Booklet (Operating Manual) 75

1.1.7 Engineering Analysis 75

1.1.8 Mooring Systems and Equipment 76

1.1.9 Material 76

1.1.10 Underwater marking 77

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1.1.11 Corrosion Protection 77

1.2 Ship - Type Vesels 80

1.2.1 General 80

1.2.2 Definitions 81

1.2.3 Longitudinal Strength 81

1.2.4 Stability , Division and Loadline 81

1.2.5 Structural Arrangement 82

1.2.6 Structural Design of the Hull 82

1.2.7 Engineering Analyses of the Hull Structure 85

1.2.8 Analysis and Design of Other Major Hull Structural Features 90

1.2.9 Marine Piping Systems 94

1.2.10 Electrical Systems 94

1.2.11 Fire Fighting Systems and Equipment 97

1.2.12 Machinery 98

1.2.13 Equipment 98

1.2.14 Safety Equipment 98

1.3 Column-stabilized Vessels 98

1.3.1 General 98

1.3.2 Definitions 99

1.3.3 Loading Criteria 99

1.3.4 Wave Clearance 99

1.3.5 Structural Design 99

1.3.6 Engineering Analysis of the Vessel's Primary Structure 101

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1.3.7 Analysis and Design of Other Major Structures 103

1.3.8 Stability 104

1.3.9 Marine Piping Systems 105

1.3.10 Electrical Systems 105

1.3.11 Fire Fighting Systems and Equipment 105

1.3.12 Machinery and Equipment 105

1.3.13 Safety Equipment 106

1.4 Existing Tanker Hull Structures (Ordinary Conversions) 106

1.4.1 Introduction 106

1.4.2 General 106

1.4.3 Alternative Acceptance Criteria for the 'Basic Design' of the Hull Structure 107

1.4.4 Assessing the 'Basic Design' of the Hull Structure 115

1.4.5 Optional: "Time to Steel Renewal" Assessment 116

1.4.6 Survey Requirements for an "Ordinary Conversion" 116

1.5 Tension Leg Platforms 119

1.6 Spar Vessels 119

PART 4: POSITION MOORING SYSTEM 121

1. Mooring system 121

1.1. Definitions 121

1.1.1. Spread Mooring 121

1.1.2. Single Point Mooring (SPM) 122

1.2. System Conditions 122

1.2.1. Intact Design 122

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1.2.2. Damaged Case with One Broken Mooring Line 123

1.2.3. Transient Condition with One Broken Mooring Line 123

1.3. Mooring Analysis 123

1.3.1. Mean Environmental Forces and Moments 124

1.3.2. Maximum Offset and Yaw Angle of the Vessel 125

1.3.3. Maximum Line Tension 126

1.3.4. Mooring Line Fatigue Analysis 127

1.4. Mooring Line Design 128

1.5. Hawser Loads 128

1.6. Dynamic Positioning Systems 129

1.7. Thruster Assisted Mooring Systems 129

1.8. Mooring Equipment 129

2. Anchor Holding Power 130

2.1. Drag Anchor 130

2.2. Conventional Pile 131

2.3. Vertically Loaded Drag Anchors (VLA) 131

2.4. Suction Piles 132

2.5. Factor of Safety 133

3. Field Test 133

4. Single Point Moorings - CALMs, SALMs, Turrets and Yokes 135

4.1. Design Loadings 135

4.2. Structural Components 135

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4.3. Mechanical Components 135

4.4. Hazardous Areas and Electrical Installations 136

4.5. Fire Fighting Equipment 136

4.6. Product Piping Systems and Floating Hoses 136

4.7 Turret Mooring 136

4.8. Turret/Vessel Structural Interface Loads 138

5. Surveys During Construction 138

PART 5 : HYDROCARBON PRODUCTION AND PROCESS SYSTEMS 141

1. Hydrocarbon Production and Process Systems 141

1.1. General requirements 141

1.2. Application 141

1.3. Subsea Equipment 142

1.4. Use other standards 142

1.5. Non-standard Equipment 142

1.6. Design and Construction 142

1.6.1 General 142

1.6.2 Arrangements 143

1.6.3 Structural Considerations 143

1.7. Process System 143

1.7.1 Submittals 143

1.7.2 Piping System and Manifolds 144

1.7.3 Pressure Relief and Depressurization Systems 144

1.7.4 Process Equipment 144

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1.7.5 Prime Movers 144

1.7.6 Safety Systems 144

1.7.7 Control System 145

1.7.8 Quick Disconnect System 145

1.7.9 Electrical Installations 146

1.8. Hazardous Area Classification 146

1.9. Fire protection 146

1.10. Fabrication and testing 146

1.10.1 Pressure Vessels, Accumulators, Heat Exchangers, Separators, and Manifolds 146

1.10.2 Pumps, Compressors and Diesel/Gas Engines 147

1.10.3 Motors and Generators 147

1.10.4 Switchboards and Control Panels 147

1.10.5 Process and Process Support Piping 147

PART 6 : IMPORT AND EXPORT SYSTEMS 149

1. Import and export systems 149

1.1. General 149

1.1.1 Riser Classification Boundaries 149

1.1.2 Basic Design Considerations 150

1.2. Submission of Plans and Design 150

1.3. Environmental conditions 151

1.4. System Design and Analysis 151

1.4.1 General requirements 151

1.4.2 Rigid Risers 151

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1.4.3 Flexible Risers 153

1.4.4 Export Vessel Transfer System 154

1.4.5 System Components 154

1.4.6 Installation Analysis 154

1.5. Material 155

1.5.1 Material for Rigid Risers 155

1.5.2 Material for Flexible Risers 155

PART 7 INSTALLATION, HOOK-UP AND COMMISSIONING 157

1. Installation, Hook-up, and Commissioning 157

1.1. General requirements 157

1.1.1. General Description 157

1.1.2. Pre-installation Verification 157

1.1.3. Pile or Anchor and Mooring Line Installation 157

1.1.4. Tensioning and Proof Load Testing 158

1.1.5. Hook-up of the Anchor Chain System 159

1.1.6. Import/Export System Installation 159

1.1.6.1. Rigid and Flexible Risers 160

1.1.6.2. Export Vessel Transfer System 160

1.1.7. Disconnecting Procedure 161

1.2. Hook-Up Procedures Submittal 161

1.3. Start-Up and Commissioning Procedures Submittal 161

1.4. Surveys during Installation of the Mooring Systems 161

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1.5. Surveys During Installation of the Import/Export System 162

1.6. Surveys during Hook-Up 163

1.7. Demonstration of the Disconnectable Mooring System 164

1.8. Surveys During Start-Up and Commissioning 164

PART 8: SURVEYS AFTER INSTALLATION AND COMMISSIONING 167

1 Class maintenance surveys 167

1.1 Periodical surveys 167

1.1.1 General 167

1.1.2 Modification of Requirements 168

1.1.3 Definitions 168

1.1.4 Survey Reports File 169

1.1.5 Corrosion Prevention System - Ballast Tanks 170

1.2 Intervarls of periodical surveys 170

1.2.1 General 170

1.2.2 Annual surveys 170

1.2.3 Docking surveys 170

1.2.4 Underwater Inspection in Lieu of Drydocking Survey (UWILD) 170

1.2.5 Intermediate surveys 171

1.2.6 Special surveys 171

1.2.7 Boiler surveys 173

1.2.8 Propeller shaft and stern tube shaft surveys 173

1.3 Annual surveys 174

1.3.1 Requirements for Annual Surveys Hull 174

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1.3.2 Annual survey for Machinery installations and Electrical Installations 179

1.4 Docking surveys 184

1.4.1 General 184

1.4.2 Requirements for Docking survey 185

1.5 Underwater Inspection in Lieu of Drydocking Survey 186

1.5.1 General 186

1.5.2 Parts to be Examined 187

1.6 Intermediate Surveys 189

1.6.1 General 189

1.6.2 Intermediate survey for hull 190

1.7 Special surveys 191

1.7.1 General 191

1.7.2 Special surveys for hull 191

1.7.3 Special surveys for Machinery Installations and Electrical Installations 197

1.8 Boiler and thermal oil heater surveys 204

1.8.1 General 204

1.9 Propeller shafts and stern tube shaft surveys 204

1.9.1 General 204

1.10 Automatic and Remote Control System Surveys 204

1.11 Annual Surveys for Inert Gas Systems 204

1.11.1 General 204

1.11.2 Alarm and Safety Device 205

1.12 Special Periodical Surveys for Inert Gas Systems 206

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1.12.1 General 206

1.12.2 Separate Inert Gas Generator System 207

1.12.3 Gas Stored in Bottles System 207

1.13 Annual Surveys Production Facilities 207

1.14 Special Periodical Surveys - Production Facilities 207

1.15 Annual Surveys - Mooring Systems 208

1.15.1 Annual Surveys - Spread Mooring Systems 208

1.15.2 Annual Surveys - Single Point Mooring (SPM) Systems 208

1.16 Special Periodical Surveys - Mooring Systems 209

1.17 Annual Surveys - Import and Export Systems 210

1.18 Special Periodical Survey Import and Export Systems 211

PART 9: SPECIFIC REGULATIONS 213

1 APPENDIX I: THE CONCEPT AND APPLICATION OF ENVIRONMENTAL

SEVERITY FACTORS (ESFS) FOR SHIP-TYPE SITE-DEPENDENT DESIGNED

FLOATING OFFSHORE INSTALLATIONS 214

1.1 ESFs of the Beta Type 214

1.2 ESFs of the Alpha Type 216

2 APPENDIX II: THE MODIFICATION OF SHIP-TYPE FLOATING PRODUCTION

SYSTEM CRITERIA FOR SITE-SPECIFIC ENVIRONMENT CONDITIONS 218

2.1 Deck Load 218

2.1.1 Loads for On-Site Operation 218

2.1.2 Load in Transit Condition 220

2.2 Sloshing Loads 220

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2.3 Green Water 220

2.4 Bow Impact Pressure 221

2.5 Bottom Slamming Pressure 222

2.6 Local Structure of the Hull Supporting Deck Mounted Equipment 224

2.6.1 General 224

2.6.2 Load Pattern No. 1 224

2.6.3 Load Pattern No. 2 231

3 APPENDIX III: EXTENT OF STRUCTURES IS TO BE ANALYSED BY FINITE

ELEMENT MODELS (FEM) 232

3.1 Methods of Approach and Analysis Procedures 232

3.2 3D Finite Element Models 232

3.3 2D Finite Element Models 232

3.4 Local Structural Models 232

3.5 Load Cases 232

4 APPENDIX IV: LOAD CRITERIA 234

4.1 General 234

4.1.1 Load Components 234

4.2 Static Loads 234

4.2.1 Still-water Bending Moment 234

4.3 Wave-induced Loads 235

4.3.1 General 235

4.3.2 Horizontal Wave Bending Moment and Shear Force 235

4.3.3 External Pressures 237

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4.4 Nominal Design Loads 243

4.4.1 Hull Girder Loads Longitudinal Bending Moments and Shear Forces 243

4.4.2 Local Loads for Design of Supporting Structures 244

4.4.3 Local Pressures for Design of Plating and Longitudinals 244

4.5 Combined Load Cases 245

4.5.1 Combined Load Cases for Structural Analysis 245

4.5.2 Combined Load Cases for Failure Assessment 245

4.6 Sloshing Loads 246

4.6.1 General 246

4.6.2 Strength Assessment of Tank Boundary Structures 246

4.6.3 Sloshing Pressures 247

4.7 Impact Loads 256

5 APPENDIX V: FATIGUE LIFE 257

5.1 Floating storage units with length more than 150 m 257

5.1.1 General 257

5.1.2 Procedures 257

5.1.3 Spectral Analysis 258

5.2 Floating storage units with length less than 150 m 259

6 APPENDIX VI: FAILURE CRITERIA YIELDING 260

6.1 Floating storage units with length more than 150 m 260

6.1.1 General 260

6.1.2 Structural Members and Elements 260

6.1.3 Plating 261

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6.2 Floating storage units with length less than 150 m 262

7 APPENDIX VII: MACHINARY, PROCESS SYSTEM ON FLOATING STORAGE

UNIT 263

7.1 General 263

7.2 Definitions 263

7.3 Plans and Particulars to be Submitted 265

7.3.1 Plans and Particulars to be Submitted 265

7.3.2 Details 267

7.3.3 Hydrocarbon Production and Process Systems 267

7.3.4 Process Support Systems 269

7.3.5 Marine Support Systems 270

7.3.6 Electrical Systems 271

7.3.7 Instrumentation and Control Systems 273

7.3.8 Fire Protection and Personnel Safety 274

7.3.9 Arrangements for Storage Tank Venting and Inerting 275

7.3.10 Arrangements for Use of Produced Gas as Fuel 275

7.3.11 Start-up and Commissioning Manual 275

7.4 Hydrocarbon Production and Process Systems 276

7.4.1 General 276

7.4.2 Process Design 276

7.4.3 Facility Layout 277

7.4.4 Piping and Instrumentation Design 280

7.4.5 Emergency Shutdown (ESD) Stations 282

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7.4.6 Pressure Relieving and Hydrocarbon Disposal Systems 282

7.4.7 Spill Containment, Open and Closed Drain Systems 286

7.4.8 Protection from Ignition by Static Charge 288

7.4.9 Major Equipment Requirements 288

7.4.10 Process Piping Systems 293

7.4.11 Packaged Process Units 294

7.5 Process Support Systems 295

7.5.1 General 295

7.5.2 Component Requirements 295

7.5.3 System Requirements 297

7.6 Electrical Systems 302

7.6.1 Applicability 302

7.6.2 Design Considerations 302

7.6.3 Rotating Electrical Machinery 306

7.6.4 Transformers 306

7.6.5 Switchgear 307

7.6.6 Wire and Cable Construction 312

7.6.7 Hazardous Areas 313

7.6.8 Ventilation 315

7.6.9 Cable Support and Installation 316

7.6.10 Power Source Requirements 316

7.6.11 Emergency Source of Power 318

7.6.12 Battery Systems 318

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7.6.13 Short Circuit Current Calculations and Coordination Study 318

7.6.14 Protection from Ignition by Static Charges 319

7.7 Instrumentation & Control Systems 319

7.7.1 Applicability 319

7.7.2 Components 320

7.7.3 Instruments 321

7.7.4 Alarm Systems 321

7.7.5 Control and Monitoring 323

7.7.6 Safety Systems 324

7.7.7 Shutdown Systems 326

7.7.8 relief valves 326

7.7.9 Shutdown valves, blowdown valves, diverter valves 327

7.8 Fire Protection and Personnel Safety 327

7.8.1 Scope 327

7.8.2 Fire Fighting Systems 327

7.8.3 Fire and Gas Detection and Alarm Systems 343

7.8.4 Structural Fire Protection 344

7.8.5 Muster Areas 348

7.8.6 Means of Escape 349

7.8.7 Lifesaving Requirements 349

7.8.8 Personnel Safety Equipment and Safety Measures 350

7.9 Survey During Construction and Commissioning 351

7.9.1 Construction Surveys 351

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7.9.2 Commissioning and Start-up Surveys 352

7.9.3 Start-up and Commissioning Manual 353

7.10 Survey for Maintenance of Class 360

7.10.1 Annual Survey 360

7.10.2 Special Survey 361

8 APPENDIX VIII: UNDERWATER INSPECTION PROCEDURE 363

8.1 Introduction 363

8.2 Conditions 363

8.2.1 Limitations 363

8.2.2 Thickness Gauging and Nondestructive Testing 363

8.2.3 Tailshaft Surveys 363

8.2.4 Plans and Data 363

8.2.5 Underwater Conditions 364

8.3 Physical Features 364

8.3.1 Stern Bearing 364

8.3.2 Rudder bearings 365

8.3.3 Sea Suctions 365

8.3.4 Sea Valves 365

8.4 Procedures 365

8.4.1 Exposed Areas 365

8.4.2 Underwater Areas 365

8.4.3 Damage Areas 365

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NATIONAL STANDARD TCVN 6474-1:2007

Second Edition

RULES FOR CLASSIFICATION AND TECHNICAL SUPERVISION OF

FLOATING STORAGE UNITS

PART 1: CLASSIFICATION

1 General requirements

1.1 Application

1.1.1 National standard Rules for classification and technical supervision of floating

storage units are applicable for all self-propelled and non-propelled floating storage

units operating in Vietnamese seas

1.1.2 This standard assigns the requirements on the classifications and constructions of

floating storage units.

1.1.3 The technical Supervision and Classification for any types of floating storage units

are to be carried out by Vietnam Register (hereinafter referred to as VR).

1.1.4 The floating storage units are to met the requirements specified in this standards and

other appropriate requirements specified in relevant regulations and reference

standards.

1.1.5 Requirements of other equivalent Rules or technical Standards may be used, if agreed

by VR

1.1.6 This standard is applied to both new building, alteration, repair of units and in

operation.

1.1.7 Units are designed or built under regulations, which is different from these

regulations, will be considered for classification by VR if safety levels are

equivalent. In this case, VR should be informed from initial design stage for accept

the basis of design.

1.2 Reference documents

1.2.1 Vietnamese standards from TCVN 6259-1: 2003 to TCVN 6259-11: 2003 Rules

TCVN 6474-1:2007

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for classification and construction of sea going ships and enclosed amendments.

1.2.2 Vietnamese standards from TCVN 5309:2001 to TCVN 5319: 2001 Mobile

offshore units - Rules for classification and construction.

1.2.3 TCVN 6968: 2005 Rules for offshore lifting apppliance

1.2.4 TCVN 6809: 2001- Rules for classification and construction of single point moorings

TCVN 6474-1:2007

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2 Definition and explaination

2.1 Floating storage units

2.1.1 Purpose

2.1.1.1 A Floating storage unit provides hydrocarbon processing and/or hydrocarbon

storage and offloads hydrocarbons. A Floating storage unit configuration may be

ship-type, semi-submersible type and other types, which is depended on its

functions as specified in 2.1.1.2.

2.1.1.2 The notations FPSO, FPS, FSO were chosen to provide a clear description of the

function of each configuration.

FPSO Floating Production, Storage and Offloading System An FPSO processes, stores

and offloads hydrocarbons.

FPS Floating Production (and Offloading) System, An FPS processes and offloads

hydrocarbons without storage capacity.

FSO Floating Storage and Offloading System, An FSO stores and offloads

hydrocarbons without hydrocarbon processing facilities.

2.1.2 Major Elements

2.1.2.1 A Floating storage unit consists of several of the following major elements:

(1) Vessel

(2) Position mooring (or station keeping system)

(3) Production processing facilities

(4) Import/export system

2.1.2.2 Classification boundaries encompass the vessel and position mooring system and

may include the production facilities. Import/export systems may be classed, as

well.

2.2 Type of floating storage units

2.2.1 Floating storage unit refers to a floating structure and the machinery, equipment and

systems necessary for safety, propulsion (if fitted) and auxiliary services. The

structural configurations of these units may be ship-shaped (with or without

propulsion), column stabilized or any other configuration of a purpose-built floating

vessel.

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2.2.2 Ship-type floating storage units are displacement hulls, either ship-shaped or barge-

shaped, which have been designed or converted to a floating production and/or

storage system. They may have propulsion machinery and/or station keeping

systems.

2.2.3 Column-stabilized Floating storage units consist of surface piercing columns,

submerged pontoons and a deck supported at column tops.

2.2.4 Other Types: Purpose-built and new configurations, such as tension leg platforms

and spar buoys, belong to this category.

2.3 Coordinates and motion

2.3.1 The coordinates of floating storage units are given in figure 1-1 below.

2.3.2 The oscillated motion of floating storage units consists three straight oscillations and

three rotating oscillations, which are called in accordance with relevant axis and

illustrated in figure 1-1.

2.3.3 Three straight oscillation consists:

Straight oscillation in X-axis Surge Straight oscillation in Y-axis Sway Straight oscillation in Z-axis Heave

2.3.4 Three rotating oscillation consists:

Rotating oscillation in X-axis Roll Rotating oscillation in Y-axis Pitch Rotating oscillation in Z-axis - Yaw

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Figure 1-1: The oscillations of floating storage unit

2.4 Production Facilities

2.4.1 General

2.4.1.1 The production facilities typically consist of the processing, safety and control

systems, production support systems and auxiliary equipment for processing

hydrocarbon liquid and gas mixtures from wells or other sources. Generally, a

production facility includes all elements located onboard the Floating Installation

vessel. These elements are located from (and including) the Christmas tree or the

first inlet flange of the well fluid flow line inboard to (and including) the last

onboard flange. Some important items related to production facilities are defined in

the following paragraphs.

2.4.2 Production Support Systems

2.4.2.1 The production support systems include power generation and distribution,

instrument and service air, potable water, fuel oil systems, HVAC, instrumentation,

communication systems and firewater systems required to support hydrocarbon

production and processing.

2.4.3 Hazardous Areas

2.4.3.1 A classified area is an area in which flammable gases or vapors are or may be

present in the air in quantities sufficient to produce explosive or ignitable mixtures.

2.4.3.2 An area classification plan is a set of drawings indicating extent, boundaries and

classification of all classified areas.

x

y

z

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2.4.3.3 Hazardous areas are divided into three zones: zone 0, zone 1 and zone 2, which are

defined as follows:

(1) Zone 0: in which an explosive gas/air mixture is continuously present or present for

long periods.

(2) Zone 1: in which an explosive gas/air mixture is likely to occur in normal operation.

(3) Zone 2: in which an explosive gas/air mixture is not likely to occur, or in which such

a mixture, if it does occur, will only exist for a short time.

2.4.4 Piping and Instrumentation Diagrams (P&IDs)

2.4.4.1 P&IDs show the size, design and operating conditions of each major process

component, piping and valve designation and size, sensing and control

instrumentation, shutdown and pressure relief devices with set points, signal

circuits, set points for controllers, continuity of all line pipes and boundaries of skid

units and process packages

2.4.5 Safety Analysis Function Evaluation (S.A.F.E.) Charts

2.4.5.1 The S.A.F.E. charts list all process components and emergency support systems

with their required sensing devices and the functions to be performed by each

device and relate all sensing devices, shutdown valves, shutdown devices and

emergency support systems to their functions.

2.5 Position Mooring System

2.5.1 General

2.5.1.1 A Position Mooring System keeps the vessel on station. The Position Mooring

System includes mooring lines, connectors and hardware, winches, piles, anchors

and thrusters. For a single point mooring system, the turret, turntable, disconnecting

system, buoy, anchoring legs, etc., are also part of the system.

2.5.2 Spread Mooring

2.5.2.1 A spread mooring is a system with multiple catenary mooring lines anchored to

piles or drag anchors at the sea bed. The other end of each line is individually

attached to winches or stoppers on the vessel through fairleads as necessary. A

catenary mooring line may have one or more line segments, in-line buoy(s) (spring

buoy) or sinker(s) (clumped weight) along the line.

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2.5.3 Single Point Mooring (SPM)

A single point mooring allows the vessel to weathervane. Three typical types of single point

mooring systems that are commonly used are described below:

2.5.3.1 CALM (Catenary Anchor Leg Mooring): A catenary anchor leg mooring system

consists of a large buoy anchored by catenary mooring lines. The vessel is moored

to the buoy by soft hawser(s) or a rigid yoke structure.

2.5.3.2 SALM (Single Anchor Leg Mooring): A single anchor leg mooring system consists

of an anchoring structure with built-in buoyancy at or near the water surface and is

itself anchored to the seabed by an articulated connection.

2.5.3.3 Turret Mooring: A turret mooring system consists of a number of mooring legs

attached to a turret that is designed to act as part of the vessel, allowing only

angular relative movement of the vessel to the turret, so that the vessel may

weathervane. The turret may be mounted internally within the vessel or externally

from the vessel bow or stern. Typically, a spread mooring arrangement connects the

turret to the seabed.

2.5.3.4 Yoke Arm A yoke arm is a structure at the end of the vessel that only allows

angular relative movement between the vessel and the mooring attachment to the

seabed.

2.5.3.5 The above mentioned types of single mooring system are illutrated in figures

below:

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Figure 1-2 : Spread mooring

Figure 1-3: External turret mooring

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Figure 1-4: Internal turret mooring

Figure 1-5: CALM with rigid york structure

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Figure 1-6: CALM Soft hawser

Figure 1-7: SALM with an articulated connection

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Figure 1-8: SALM with vertical hawser and connection rope

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2.5.4 Dynamic Positioning and Thruster Assisted Systems

2.5.4.1 A dynamic positioning system is defined as all of the equipment necessary to

provide a means of controlling the position and heading of a Floating Installation

within predetermined limits by means of vectored thrust.

2.5.4.2 A thruster-assisted system provides controlled thrust to assist the main (usually

static) mooring system and reduce component loading of the main mooring system

2.6 Subsea System

2.6.1 General

2.6.1.1 A subsea system is a flexible/articulated piping system providing a conduit for the

hydrocarbons from the subsea pipeline to the surface components. It includes

subsea pipelines, subsea well system and risers.

2.6.2 Floating Hose

2.6.2.1 A floating hose is a floating conduit used to export hydrocarbons from a point of

storage/production, either an SPM or vessel's manifold to a receiving vessel's

manifold for transport.

2.6.3 On Bottom Flexible Flow Lines

2.6.3.1 These lines are conduit used to connect one subsea location to another subsea

location prior to a vertical conveyance by the riser system to the surface.

2.6.4 Pipe Line End Manifold (PLEM)

A PLEM is the assemblage of valves and components or equipment performing the

equivalent function connecting the production facilities to the pipeline carrying product to

or from the shore, an offloading system or to another facility.

2.6.4.1 Import PLEM: Import PLEM is the equipment connecting to the Import Riser and

the import supply line or wellhead.

2.6.4.2 Export PLEM: Export PLEM is the equipment connection between the Export Riser

and the product discharge line

2.6.5 Riser

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A riser is a subsea rigid or flexible pipe that connects the surface facilities with the sea floor

and thus the conduit for fulfilling the desired function of conveying fluids, gas, electrical

power, etc.

2.6.6 Riser System

The riser system includes the entire assemblage of components, control systems, safety

systems and tensioning devices that ensure the integrity of the riser throughout its operation.

2.6.7 Riser Support

Riser support comprises any structural attachments, including buoyancy devices that are

used to give structural integrity to the riser or transfer load to the supporting structure.

2.6.8 Submerged Jumper Hoses

Jumper hoses are flexible lines used in conjunction with rigid risers to accommodate the

relative motion between the Floating Installation and the submerged top of the riser. Jumper

hoses may also be used to connect the subsea manifold to the wellhead.

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3 Classification

3.1 Class assignation

3.1.1 Units will be assigned a class and registered in VR Offshore Register book by VR

when it is designed, constructed and surveyed in compliance with requirements of

these regulations.

3.2 Class of floating storage units

3.2.1 Scope of classification for floating storage units

3.2.1.1 Scope of classification for floating storage units consists three main items: hull of

floating storage units, position mooring systems and production facilities.

3.2.1.2 Other items such as import/export system may be classed if requested by floating

storage units owner.

3.2.2 Basic characters of classification for floating storage units

The floating storage unit classed by VR will be assigned a class with following characters

when it was found satisfactory with the requirements specified in this standards:

VR or VR or ()VR VR : Symbol of VR showing the supervision of units in compliance with the

requirements of this standard.

* : Construction carried out under supervision of VR

* : Construction carried out under supervision of a Classification Society authorized

or/and recognized by VR

(*) : Construction without supervision of VR or under supervision of a Classification

Society.

These characters also use when classification service was carried out by VR for specific

items or parts of floating storage unit as requested by owner.

3.2.3 Class notations of hull of floating storage units

Characters of the classification and notations of the hull are as follows:

* VRH : Hull design has been approved by VR in compliance with the Rules and hull

has been constructed under supervision of VR in compliance with the approved plans

and drawings.

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* VRH : Hull design has been approved by a Classification Society recognized or/and

authorized by VR and hull has been constructed under supervision of that Society and

then surveyed by VR in compliance with the Rules.

(*) VRH : Hull design has not been approved by any Classification Society (or has

been approved by an unrecognized Classification Society) and hull has been

constructed without supervision of any classification (or under supervision of an

unrecognized Classification Society) and then surveyed by VR in compliance with the

Rules.

3.2.4 Class notations of machinery of floating storage units

Due to almost existing and new building floating storage units are non-propelled and

machinary systems in floating storage unit consist electrical generators and other machinary

in machinary room, following characters of classification is assigned by VR to machinary

system of floating storage units. The mentioned machinary system here is meant electrical

generator and other machirary in machinary room:

* VRM: Machinery installations design has been approved by VR in compliance with

the Rules and machinery installations have been constructed under supervision of VR

in compliance with the approved plans and drawings.

* VRM : Machinery installations design has been approved by a Classification Society

recognized or/and authorized by VR and machinery installations have been constructed

under supervision of that Society and then surveyed by VR in compliance with the

Rules.

* VRM : Machinery installations design has not been approved by any Classification

Society (or has been approved by an unrecognized Classification Society) and

machinery installations have been constructed without supervision of any

Classification Society (or under supervision of an unrecognized Classification Society)

and then surveyed by VR in compliance with the Rules.

3.3 Subdivision notation and additional notations

3.3.1 Subdivision notation

A Floating storage unit which complies with the applicable requirements of Part 9 "

Subdivision" TCVN 6259-9: 2003, one of the Subdivision distinguishing notations is added

to the characters of classification as , , . These figures denote the condition that the 321

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unit still remains afloat in a satisfactory state of equilibrium in compliance with the

requirements of Chapter 3, Part 9 TCVN 6259-9: 2003 if any one compartment or any two

or three adjacent compartments of her is/are flooded.

3.3.2 Notation for in water survey of submerged part of hull of floating storage units.

If requested by units owner and the floating storage unit was found satisfactory with VRs

requirement for in-water survey of submerged part of hull (see clause 1.2.4 TCVN 6474-8),

the floating storage unit shall be assigned following additional notation: IWS (in water

survey)

3.3.3 Notation for enhanced survey programme

For floating storage units, which are to be applied the enhanced survey programme (see

clause 1.7.2 TCVN 6474-8) in surveys for class maintenance in appropriate requirements

specified in part 1B TCVN 6259-1: 2003, the class character of floating storage unit will be

added following notation: ESP (Enhanced Survey Programme).

3.3.4 Notation for function of floating storage units

3.3.4.1 The charaters of classification of floating storage units will be added following

notations depended on functions of the units:

FPSO Floating, production, storage and offloading systems

FPS - Floating, production and offloading systems

FSO - Floating, storage and offloading systems

3.3.4.2 If the floating storage unit has a function differed with functions mentioned in

3.3.4.1, the additional notation for function of floating storage unit will be

considered by VR for each case.

3.3.5 Dynamic positioning system

3.3.5.1 If dynamic positioning systems were installed for station keeping purposes in

floating storage unit , the charaters of classification of floating storage units will be

added a notation DPS.

3.3.6 Notations for location and operational condition

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If the unit is operated in a particular location and when maximum loads incluced by wave,

wind, ice and current in that location have been considered then the location, loads and ice

reinforcement shall be stated in classification certificate .

3.3.7 Example for charaters and notations of classification

* VRH, *VRM FSO IWS BACH HO FIELD Class notation of floating unit, storage,

offloading, unit has been constructed under supervision of VR, unit has notation for in-

water survey of submerged part of hull, the unit is operated in Bach Ho field.

* VRH, *VRM FPSO EPS DPS DRAGON FIELD Class notation of floating unit,

storage, production, offloading, Construction carried out under supervision of a

Classification Society authorized or/and recognized by VR, unit has notation for Enhanced

Survey Programme, unit has notation for dynamic positioning system, the unit is operated in

Dragon field.

3.4 Class maintenance

3.4.1 The units which have been classed with VR will maintain the assigned class and

character until, as a result of surveys inspections or test which have been carried out,

the units are found to be in fully compliance with the relevant requirements of this

standard.

3.4.2 Any damage or defect which may affect the class assigned is to be reported to VR

without delay and an application for surveys is to be submitted by Owner/operator or

their representative .

3.5 Suspension of Class

3.5.1.1 The class assigned to a unit by VR will be suspended under any one of the

following conditions:

(1) Class is suspended for any use, operation, loading condition or other application of

any vessel for which it has not been approved by VR and that affects or may affect

classification or the structural integrity, quality or fitness for a particular use or

service.

(2) If the periodical surveys required for maintenance of class are not performed by the

due date and no Rule-allowed extension has been granted by VR, class will be

suspended

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(3) If recommendations issued by the VR are not performed within their due dates, class

will be suspended.

(4) When the Owner fails to repair such damages and defects that affect the class of the

unit in accordance with VR requirements;

(5) Class will be suspended for any damage, failure, deterioration or repair that has not

been completed as recommended by VR

3.5.1.2 If proposed repairs have not been submitted to VR and agreed upon prior to

commencement, class may be suspended

3.6 Lifting of Suspension

3.6.1 Class will be reinstated after suspension for

(1) overdue surveys upon satisfactory completion of the overdue surveys.

(2) overdue recommendations upon satisfactory completion of the overdue

recommendation.

(3) overdue continuous survey items upon satisfactory completion of the overdue items.

3.7 Withdrawal of class and chance character of classification

3.7.1 The class assigned to a unit by VR will be withdrawal under any one of the following

conditions:

(1) If the circumstances leading to suspension of class are not corrected within the time

specified, the unit's class will be withdrawal;

(2) VR recognized that the unit can no longer be used ;

(3) When requested by the Owner of the unit;

(4) Survey fees are not paid by the owner .

3.7.2 VR will change or wihdraw class notation stated in Classification certificate if there

is change or violation of principle conditions which are basis for classification of

unit.

3.8 Reclassification

3.8.1 When reclassification or class reinstatement is desired for a unit for which the class

previously was assigned by VR and has been withdrawn, a special survey for

reclassification, appropriate to the age and technical conditions of the unit, will be

carried out by VR.

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3.8.2 If, at such survey, the unit is found that its conditions are fully compliance with the

regulations, VR may reinstate its original class or assign such other class as may be

deemed necessary .

3.9 Requisition for a survey

3.9.1 Classification survey

The classification survey and registration will be carried out by VR when received a

requisition by units owner or shipyard.

3.9.2 Survey for class maintenance

The periodical survey for class maintenance will be carried out when received a requisition

for a survey by units owner, barge captain or owners representative.

3.10 Certificate of Classification

3.10.1 Issurance of Classification Certification

Upon the completion of the construction survey, classification survey for first entry of

reclassification survey of a unit, if it is found that the unit complies fully with this standard,

a classification certificate will be issued to the floating storage unit by VR.

3.10.2 Endorsement of Classification Certificates

The Classification Certificate for Units issued by VR will continue to be valid, provided that

the units are subjected to the annual surveys for maintenance of class as prescribed of the

Regulations and results of the surveys are found satisfactory to the requirements of the

Regulations

3.10.3 Issuance of Provisional Classification Certificates

Pending the issuance of the Classification Certificate, where a result of surveys is found that

the unit is in a fit an efficient condition and in compliance with the regulations, VR may

issue a corresponding Provisional Classification Certificates to enable the unit to be put into

service in the shortest possible period of time .

3.10.4 Validity of Certificate of Classification and Provisional Certificate of Classification

3.10.4.1 A Certificate of Classification shall be valid for a period not exceeding five years.

The validity of the Certificate of Classification may be extended for five months

from the date of completion of the Special Survey when a registered unit has been

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subjected to a Special Survey in accordance with the Rules to the satisfaction of the

Surveyor.

3.10.4.2 A Certificate of Classification, the validity of which has been extended as described

in 3.10.4.1 above, is to become invalid upon issue of the new Certificate of

Classification.

3.10.4.3 A Provisional Certificate of Classification is valid for five months from the date of

issue of the Provisional Certificate of Classification. The Provisional Certificate of

Classification is to become invalid upon issue of the Certificate of Classification.

3.10.4.4 The full term classification certificate and provisional classification certificate is

invalid when the class has been withdrawn as specified in clause 3.7.

3.10.4.5 The certificate of classification of the unit is invalid if not satisfied the requirements

in 3.10.2.

3.10.5 Retention, Reissue, Rewriting and Return of Certificate of Classification

3.10.5.1 The master of a unit is to keep a Certificate of Classification or a Provisional

Certificate of Classification on board the ship and present the same to VR upon

request.

3.10.5.2 The owner or master of a ship is to request VR without delay to reissue a Certificate

of Classification or a Provisional Certificate of Classification when the same is lost

or soiled.

3.10.5.3 The owner or master of a unit is to request VR without delay to rewrite a Certificate

of Classification or a Provisional Certificate of Classification when the particulars

described in the same are changed.

3.10.5.4 The owner or master of a unit is to return a Provisional Certificate of Classification

when the Certificate of classification has been issued under the provisions of 3.10.1

or five months have passed from the date of issue of a Provisional Certificate of

Classification and is to return the old Certificate if the Certificate has been issued

under the provisions of 3.10.1 above to the VR immediately except the case the

Certificate was lost.

3.10.5.5 The owner or master of a unit is to return a Certificate of Classification or a

Provisional Certificate of Classification to VR immediately when the class is

withdrawn under 3.7.

3.10.5.6 The owner or master of a unit is to, when a lost Certificate of Classification or a lost

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Provisional Certificate of Classification is found after reissuing the same under

3.10.5.2 above, return the Certificate found to VR immediately.

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4 Technical documentation

4.1 Design documents for submission

4.1.1 Design documents for submission

4.1.1.1 Prior to the commencement of the work on the new construction, modification of

units or manufacture of materials and article liable to supervision by VR, the

technical design documentation within a scope determined in the relevant parts of

the Rules shall be submitted to VR for review and approval. If necessary, VR's may

require the documents to be submitted on a wider scope.

4.1.1.2 The scope of technical documentation for units or products of special design,

submitted for review and approval by VR is established in every particular case

upon agreement with VR.

4.1.2 Amendments to approved technical documentation

The unit designer, who intends amendments to the technical documentation approved by

VR shall submit the amendment documentation to VR enclosed with the unitowner's

acceptance for VR review and approval before work commencement.

4.1.3 Submission of final design documentation

The final design documentation shall be submitted to VR for approval before VR issues a

Classification Certificate to the unit.

4.1.4 Requirements for the technical documentation for approval

4.1.4.1 There must be enough data in the technical documentation submitted to prove that

the requirements of the Rules have been fully satisfied.

4.1.4.2 Calculations for determining the parameters or data by a standard are to comply

with the requirements of this standard, or by a method approved by VR.The

calculation method used must ensure accuracy.

4.1.4.3 Approval of the technical documentation relating to the requirements of the Rules is

confirmed by putting corresponding stamps of VR on it.

4.1.5 Duration of validity of approved technical documentation

4.1.5.1 Duration of validity of technical documentation approved by VR is as follows:

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The technical documentation of a unit for new construction approved by VR remains valid for a period of 5 years from the date of stamping.

Interval between the date of approval of the documentation and the commencement of the work on the construction a unit does not exceeds two and a half years

By the expiry of above term, the designer is required to submit the design documentation

again for approval. The scope of added documentation is to be accepted by VR.

4.1.5.2 In addition to requirements specified in 4.1.5.1 above, the technical documentation

approved by VR shall be submitted to alterations necessitated by the provisions of

amendments to the International Conventions and International Codes to which the

country whose flag a unit flies is a party.

4.1.5.3 In addition, all the documents and plans approved by VR shall be altered to comply

with the instructions circulated by VR which provides for their unconditional

fulfillment in units under construction, reconstruction or conversion.

4.2 Documents issued by VR

4.2.1 Documents issued in compliance with the Rules

4.2.1.1 The units classed with VR shall get the certificates specified in 3.10 of this part if

they have been surveyed and certified by VR Surveyors in compliance with the

requirements of the Rules.

4.2.1.2 Besides the certificates referred in 4.2.1.1 above, VR shall issue survey reports and

other technical documents in compliance with the contents and survey results

carried out by Surveyor.

4.2.2 Seaworthiness certificate

4.2.2.1 The following Vietnamese flagged units shall obtain the Seaworthiness certificate if

they have been surveyed and certified by VR in compliance with the requirements

of these Rules and other applicable Rules as well as the requirements of the

International Conventions applicable for the units:

(1) Units classed with VR

(2) Units dually classed with VR and another Classification Society

(3) Units having double classes of which one is VR's class

4.2.2.2 The validity of the Seaworthiness certificate shall not exceed the validity of the

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classification certificate and the certificates issued in accordance with the

requirements of the national Regulations and/or the certificates issued in

compliance with the requirements of the International Conventions (if applicable),

the next periodical surveys and/or the period which the VR set out for the unitowner

to clear the recommendations, whichever is shortest.

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5 Classification Surveys

5.1 Classification Surveys during Construction

5.1.1 General

In the Classification survey during construction, surveys are to be carried out on hull

construction, equipment, machinery, construction of fire protection, means of escape, fire

extinguishing arrangements, electrical installation, stability and load line and positioning

systems in order to ascertain that they meet the relevant requirements of VR.

5.2 Submission of Plans and Documents for Approval

In the Classification Survey during construction, plans and documents as listed below are to

be submitted for the approval by VR before the work is commenced, if applicable:

5.2.1 Hull of floating storage units

5.2.1.1 Ship-type units

(1) General arrangement;

(2) Transverse sections showing scantlings;

(3) Longitudinal sections showing scantlings;

(4) Shell expansion ;

(5) Construction profile;

(6) Cross curves of stability

(7) Curves of righting moment and wind heeling moment

(8) Capacity plans and sounding tables of tanks

(9) Summary of distributions of fixed and variable weights for each reviewed condition;

(10) Type, location and quantities of permanent ballast;

(11) Plans indicating arrangement of watertight compartments, openings, their closing,

their closing applicances, etc. necessary for calculation of stability;

(12) Diagrams showing the extent to which the watertight and weathertight integrity is

intended to be maintained;

(13 ) Construction of frames, pillars and longitudinal girders under deck;

(14) Construction of single bottoms and double bottoms and deck construction including

details of helicopter deck, openings such as hatchways, wells, etc.;

(15) Construction of watertight and oiltight bulkhead and deep tanks indicating the

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heights of the highest parts of tank and the tops of overflow pipes;

(16) Tank bulkheads and flats with level of top of overflows and air pipes;

(17) Construction of stem, sternframe, propeller post and rudder;

(18) Construction of superstructures end deckhouses including their end bulkhead;

(19) Arrangements to resist painting of both peaks and their vicinity;

(20) Seatings of engines, boilers, thrust, blocks, plummer blocks, dynamos and other

essentially important auxiliary machineries;

(21) Foundations for anchoring equipment, industrial equipment, etc., where attached to

hull structure, superstructures or deckhouses;

(22) Turret mooring and yoke connection including mechanical details;

(23) Corrosion control arrangements;

(24) Methods and locations for nondestructive testing and procedures for thickness

measurements;

(25) Construction of machinery rooms, pump rooms and motor rooms including their

casings and shaft tunnels ;

(26) Masts, mast houses;

(27) Pumping arrangements;

(28) Arrangements and construction of watertight doors, hatchways, side scuttles and

closing appliances of openings ;

(29) Construction for fire protection with materials used in the construction of

superstructures, bulkheads, decks, deckhouses, trunks, stairways, deck coverings,

etc. and arrangements of closing appliances of openings and means of escape;

(30) Fire extinguishing arrangements;

(31) Details of inspection facilities;

(32) Details of welding procedures;

(33) Details of painting and corrosion control procedures;

(34) Details of maintenance and inspection procedures;

(35) Stability information booklet;

(36) Loading manual, where the loading manual is to be provided in accordance with the

requirement of 1.1.4 part 3;

(37) Temporary mooring arrangements, towing arrangements and arrangements of

positionings systems for a long period of time;

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(38) Arrangements and construction of positioning systems;

(39) Plan indicating design loadings for all decks;

(40) Details of docking plan and in-water inspection procedures;

5.2.1.2 For column stabilized type units

In addition to the relevant plans or documents specified in 5.2.1.1, Plans and documents for

construction of all columns, lower hull, upper hull, bracings, footings and below documents

are to be submitted for the approval by VR:

The following information is to be submitted and appropriate relevant information is to be

provided in the Operating Manual:

(1) Inspection plans for all compartments below the maximum immersion line;

(2) Closure means for external openings whose lower edges are below the levels to

whichweathertight integrity is to be ensured;

(3) A plan identifying the disposition (open or closed) of all non-automatic closing

devices and locations of all watertight and weathertight closures for each mode of

operation afloat is to be submitted for review prior to the vessels delivery. Upon

satisfactory review, the plan is to beincorporated into the Operating Manual;

(4) Means for detection of and recovery from flooding of compartments that lie partly or

completely below the operating or survival drafts and are adjacent to the sea or

contain salt water piping or pumping equipment;

(5) The estimated time to deballast the vessel from operating to survival draft;

(6) Means of preventing progressive flooding via sounding tubes, tank vents and

overflows, ventilating systems, trunks, etc., from compartments within the assumed

damaged areas;

(7) Means of detecting flooding of and means of water removal from void spaces not

connected to the bilge or ballast systems;

(8) Means of closure and evacuation of water from chain lockers;

(9) The remaining or residual range of stability resulting from the damaged condition

and the type and location of appropriate closures to prevent downflooding;

(10) Means of sounding tanks;

(11) A description of the ballast piping and control system describing the items listed :

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(a) Redundancy of pumps, valves and controls and alternate means of valve operation.

(b) Valve operating and indicating means.

(c) Means of manual and remote operation of ballast pumps and valves.

(d) Communication means between ballast control spaces and pump rooms, including

those means of communication that are independent of the ships service

communication system.

(e) Means of determining the failure of critical ballast system components and means to

overcome their failure.

5.2.2 Position Mooring System

5.2.2.1 Mooring Arrangement or Pattern;

5.2.2.2 Details of winching equipment;

5.2.2.3 Details of anchoring system;

5.2.2.4 Details of mooring line segments;

5.2.2.5 Connections at anchors and between mooring line segments;

5.2.2.6 Details of in-line (spring) buoys;

5.2.2.7 Details of buoy for CALM system (see definition in 2.5) ;

5.2.2.8 Details of SALM structures, if appropriate (see definition in 2.5) ;

5.2.2.9 Details of Turret System to show turret structure, swivel, turntable and

disconnecting device ;

5.2.2.10 Details of yoke (hard or soft) connecting the vessel and CALM/SALM structure(see

definition in 2.5) ;

5.2.2.11 Environmental Report;

5.2.2.12 Mooring Analysis describing method of load calculations and analysis of dynamic

system todetermine the mooring line design loads ;

5.2.2.13 Model Test report when the design loads are based on model tests in a wave basin

(applicable only for first unit in new building series);

5.2.2.14 Thruster specifications and calculations of a system with dynamic positioning

system for thruster forces and power to counteract environmental forces;

5.2.3 Production Facilities and Production Support Facilities

The following design documentation and documentation specified in appendix VII, Part

9 of a floating production and storage system is required to be submitted, as applicable :

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(1) General Arrangements showing arrangements and locations of storage tanks,

machinery, equipment, living quarters, fire walls, emergency shutdown (ESD)

stations, control stations, crude loading and discharge stations and the flare (see

Part 5);

(2) Hazardous Area Classification Plans, as defined in 2.4.3 herein;

(3) Details of Storage Tank Venting and Inerting indicating arrangements for storage

tank venting and inerting;

(4) Arrangements for Use of Produced Gas as Fuel showing piping and control

arrangements for use of produced gas as fuel showing details of double wall or

ducting arrangements for the pipe runs in way of the safe space;

(5) A design specification that is to include design parameters (environmental

conditions, geographical location of the unit, external loads, pressures,

temperatures, etc.), standards and codes adopted throughout the design,

construction and testing stages and the process description;

(6) A description of the field development plan, including well fluid properties,

production rates, gas oil ratios, processing scheme, well shut-in pressures;

(7) Process flow sheets showing major process equipment components, process piping,

material balance, normal pressures and temperatures at the inlet and outlet of each

major component;

(8) Piping and Instrumentation Diagrams (P&IDs) indicating location of all sensing and

controlling elements on the process and production support systems, sizing and

material specification of piping and the associated components, maximum design

pressure and temperature ratings, piping strength and flow calculations ;

(9) List of electrical equipment located in hazardous areas together with the certificates

issued by an independent testing laboratory to show suitability of their use in the

intended location;

(10) Electrical one line diagram showing ratings of all generators, motors, transformers,

type and size of wires and cables. Types and rating of circuit breakers with the

setting, interrupting capacity of circuit breakers and fuses;

(11) Short circuit current calculations and coordination data giving the maximum

calculated short circuit current available at the main bus bars and at each point in

the distribution system in order to determine the adequacy of the interrupting

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capacities of the protective device;

(12) Safety Analysis, including Safety Analysis Function Evaluation (S.A.F.E.) charts;

(13) Emergency shutdown system (ESD) relating to all sensing devices, shutdown

valves, shutdown devices and emergency support system to their functions and

showing ESD logic for the complete process and the subsea valves system;

(14) Emergency backup and uninterrupted power source, supply and the consumers;

(15) Pressure vessel (fired and unfired) and heat exchangers, design dimensional

drawings, design calculations, material specifications, pressure and temperature

ratings, together with weld details and the details of their support;

(16) Pressure relief and depressurization vent systems showing arrangements sizing of

the lines, capacities of the relief valve, materials, design capacity, calculations for

the relief valves, knock out drums, anticipated noise levels and gas dispersion

analyses;

(17) Complete details of flares, including pilots, igniters and water seal and design

calculations, including stability and radiant heat analyses;

(18) Schematic plans for the production support systems, including the size, wall

thicknesses, maximum design working pressure and temperature and materials for

all pipes and the type, size and material of valves and fittings;

(19) Compressors, pumps selection and control arrangements, including specification

data sheet;

(20) Fire and gas detection system showing the location and detailed description of all

power sources, sensors, annunciation and indication, set point for the alarm system;

(21) Passive and active fire protection system indicating locations of fire walls, fire

pumps and their capacities, main and backup power supply, fixed and portable fire

extinguishing, and fire fighting systems and equipment. In this regard, supportive

calculations are to be submitted to show the basis of capacities and quantities of fire

extinguishing equipment;

(22) Escape route plan ;

(23) Startup and commissioning procedures detailing sequence of events for inspection,

testing and startup and commissioning of equipment and system;

(24) Installation, Hook-up and Commissioning Procedures (see part 7);

5.2.4 Import/export system

TCVN 6474-1:2007

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The design documentation required to be submitted is specified in Part 6.

5.2.5 Machinery installations and electrical installations

5.2.5.1 Machinery arrangement of machinery spaces, pump rooms, motor rooms and

diagrams for internal communication systems including a diagram for an engineers'

alarm systems;

5.2.5.2 For machinery installations used for the system or the equipment essential for the

safety of the unit or for the propulsion of the unit ( only applicable to the unit which

has the main propulsion machinery) : plans and documents required in the relevant

in TCVN 6259-3:2003;

5.2.5.3 For machinery installations used solely for the operation which is the purpose of the

unit: plans and documents specified in Chapter 2, Chapter 3, Chapter 9 and Chapter

10 TCVN 6259-3:2003 for diesel engines, steam turbines, boilers and incinerators,

plans and documents specified in Chapter 13, TCVN 6259-3:2003 for piping

systems, valves and fittings, plans and documents specified in Chapter 16, chapter

17. chapter 18 and chapter 19 for windlasses and mooring winches, refrigerating

machinery, systems of automatic and remote control, spare parts, tools and

instruments.

5.2.5.4 For the units provided with the dynamic positioning system

Construction and control diagrams of dynamic positioning system

5.2.5.5 Plans and documents for electrical installations specified in 1.1.6 TCVN 6259-

4:2003

5.2.5.6 Other plans and/or documents deemed necessary by the VR

5.2.6 Manuals and Procedures

5.2.6.1 Manuals

(1) Loading Manual (see clause 1.1.4 part 3)

(2) Trim and Stability(see clause 1.1.5 part 3)

(3) Operation manual (see clause 1.1.6 part 3)

5.2.6.2 Procedures

(1) Disconnecting Procedure, if applicable(see clause 1.1.7 part 7)

(2) Drydocking Procedure (see clause 10.4)

TCVN 6474-1:2007

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(3) Hook Up Procedures (see clause 1.2 part 7)

(4) Import/Export System (see clause 1.1.4 part 6 and 1.1.6 part 7)

(5) Installation Procedures and manuals (see clause 1.1 part 7)

(6) Startup and Commissioning Procedures Survey (see clause 1.3 part 7)

(7) Inspection Planning Document (see part 8)

5.3 Presence of Surveyor

5.3.1 The presence of the Surveyor is required at the following stages of the work in

relation to hull and equipment:

5.3.1.1 When the material and equipments tests prescribed relevant parts are carried out

5.3.1.2 When the materials or parts manufactured away from the site are being applied to

the unit concerned

5.3.1.3 When the tests of welding prescribed in relevant Part are carried out

5.3.1.4 When designated by the Society during shop work or sub-assembly

5.3.1.5 When each block is assembled

5.3.1.6 When hydrostatic tests, watertight tests and non-destructive tests are caried out

5.3.1.7 When hull is completed

5.3.1.8 When performance tests are carried out on closing appliances of openings, remote

control devices, steering gears anchoring and mooring arrangements, piping, etc

5.3.1.9 When installing of rudder, profiling of keel line, measurement of principal

dimensions, measurement of deflection of hull, etc. are carried out

5.3.1.10 When the units are marked with the load lines in accordance with the requirements

in TCVN 6259-11:2003

5.3.1.11 When mooring systems are fitted on board and performance tests are carried out

5.3.1.12 When sea trials are carried out

5.3.1.13 When installing of fire extinguishing arrangements, and when the performance tests

are carried out

5.3.1.14 When inclining tests are carried out

5.3.1.15 For column stabilized units, when the draught scales are fitted

5.3.1.16 When deemed necessary by the VR;

5.3.2 The presence of the Surveyor is required at the following stages of the work in

relation to machinery installations and electrical installations

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5.3.2.1 When the tests of materials of main parts machinery prescibed in Part 7-A TCVN

6259-7:2003 are carried out

5.3.2.2 When the materials are applied to the parts and the parts are installated on board

5.3.2.3 When machining of the main parts is finished and, if necessary, at a proper time

during machining

5.3.2.4 In case of welded construction, before welding is commenced and when it is

completed

5.3.2.5 When shop trials are carried out

5.3.2.6 When important machinery installations and electrical installations are installed on

board

5.3.2.7 When performance tests are carried out on, remote control devices of closing

appliances, remote control devices, steering gears, mooring arrangements, piping,

etc

5.3.2.8 When each component consisting of a dynamic positioning systemis fitted on board

and ferformance tests of each component are carried out

5.3.2.9 When sea trials are carried out

5.3.2.10 When deemed necessary by the VR

5.3.3 The requirements specified in 5.3.1 and 5.3.2 may be modified having regard to the

actual status of facilities, technical abilities and quality control at the work, except

the case of sea trials and stability experiments

5.4 Hydrostatic and Watertight tests

5.4.1.1 Hydrostatic and watertight tests in the Classification Survey during construction are

to be in accordance with the requirements in 2.1.6, Chapter 2, Part 1-B General ,

TCVN 6259-1:2003

5.4.1.2 Notwithstanding the requirement in 5.3.4.1, where considering the design condition

and these are approved by the VR, hydrostatic and watertight tests are to be

appropriate to the VR

5.5 Classification Survey of Unit not built under Survey

5.5.1 General

5.5.1.1 In the Classification Survey of Unit not built under VR's survey, the actual

scantlings of main parts of the unit are to be measurd in addition to such

TCVN 6474-1:2007

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examination of the hull and equipment, machinery installations, construction of fire

protection and detection, means of escape, fire extinguishing arrangements,

electrical instalations, stability and load lines and positioning systems as required

for the special survey corresponding to the units' age in order to ascertain that they

meet the relevant requirements in the Rules

5.5.1.2 The units intended to be surveyed in accordance with -1, necessary plans documents

are required for the classification survey during construction are to be submitted for

the approval by the VR

5.5.2 Tests

5.5.2.1 Hydrostatic and watertight tests are to be carried out in accordance with the

requirements in 5.4

5.5.2.2 The stability experiments are to be carried out in accordance with the requirements

in this standard. Where sufficient information based on previous stability

experiments is available and neither alteration nor repair affecting the stability has

been made after previous experiments, the stability experiments of the unit may be

dispensed with. However, the dispension for stability experiments is not applied for

column stabilized unit.

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NATIONAL STANDARD TCVN 6474-2:2007

Second Edition

RULES FOR CLASSIFICATION AND TECHNICAL SUPERVISION OF

FLOATING STORAGE UNITS

PART 2: ENVIRONMENTAL LOADING AND DESIGN BASIC

Reference standards and definitions: see Part 1, TCVN 7474-1: 2007.

1 Environmental Loading and Design Basis

1.1 Design Basis

The design basis of a Floating Installation is to identify the production rate, storage

capacity and loading capabilities. Since the system is site-specific, the

environmental condition of the site directly influences the design of such a system.

The effects of prevailing winds are to be considered to minimize the risk of vented

or flared hydrocarbons to personnel, living quarters and evacuations means.

Generally, atmospheric vents, flare systems and emergency gas release vents are to

be arranged in such a way so that prevailing winds will carry heat and/or unburned

gases away from potential ignition sources on the installation.

The design environmental conditions are to include those for the operating,

installation and transit portions of the Floating Installation's design life. This Part

specifically covers the environmental design criteria for:

(1) Position Mooring System.

(2) Structural Strength and Fatigue Life Assessments

1.2 Design Documentation

The design documentation submitted is to include the reports, calculations, plans

and other documentation necessary to verify the structural strength of the vessel

itself and adequacy of the mooring system, production and other utility facilities

and riser system (if included in the classification) for the intended operations.

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1.3 Design Conditions

1.3.1 Position Mooring System

The position mooring system of a Floating Installation is to be designed to survive

in the Design Environmental Condition and operate in the Design Operating

Condition. For a disconnectable mooring system, the limiting condition at which

the mooring system is to be disconnected or reconnected is to be specified.

1.3.1.1 Design Environmental Condition (DEC)

The Design Environmental Condition (DEC) is defined as the extreme condition

with a specific combination of wind, waves and current for which the system is to

be designed.

The DEC is to be one of the following combinations that results in the most severe

loading case:

100-year waves with associated wind and current. 100-year wind with associated waves and current.

In areas with high current, additional design environmental load cases may need to

be considered.

The 100-year waves are normally characterized by a significant wave height with a

spectral shape type and a range of associated peak wave periods.

A minimum return period of 100 years for the DEC is required for Floating

Installations. A minimum return period of 50 years will be specially considered if it

is accepted by VR. Any environmental combinations with return periods shorter

than that of the DEC which induce larger mooring load responses are to be used in

the design.

1.3.1.2 Design Operating Condition (DOC)

The Design Operating Condition (DOC) is defined as the limiting environmental

condition that would require suspension of normal operations.

1.3.1.3 Design Installation Condition (DIC)

The Design Installation Condition (DIC) is defined as the limiting environmental

condition that would require suspension of installation operations. Specific limits

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on environmental conditions affecting safe operation during the installation phases

described in Part 7 are to be established and documented.

1.3.1.4 Angular Separation of Wind, Current and Waves

For single point mooring systems, which allow the vessel to weathervane, both

collinear and non-collinear directions among wind, current and waves are to be

considered. Proper angular separation for the DEC of wind, current and waves is to

be determined based on the site-specific environmental study. If this information is

not available, the following two angular combinations for non-collinear

environments can be considered as a minimum:

(1) Wind and current are collinear and both at 30 degrees to waves.

(2) Wind at 30 degrees to waves and current at 90 degrees to waves.

For spread mooring systems with limited change in vessel heading angles (less than

20 degrees) under design environmental loads, the collinear environments of wind,

current and waves, which are generally controlling, can be used in design.

For each design sea state, a long-crested sea without spectral energy spreading in

direction is normally considered in the mooring analysis

1.3.2 Structural Strength and Fatigue Life

1.3.2.1 Project Site

The site-specific wave conditions, including both long-term extreme events and

wave scatter diagram data of wave height/period joint occurrence distribution, are

to be considered for the vessel's hull strength and fatigue life assessment. A

minimum return period of 50 years for the structural response will be specially

considered, provided that it is accepted by VR. Different environmental conditions

may induce different worst responses on various parts of the hull structure. The

wave-induced maximum motion responses and maximum structural load effects

may result from different wave periods. Therefore, the following environmental

conditions are to be considered:

(1) 100-year return period waves characterized by a significant wave height with

a range of associated peak wave periods. Both winter storms and tropical

cyclones (hurricanes or typhoons), if any, need be considered.

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(2) Wave scatter diagram data of wave height/period joint occurrence distribution.

The length of time on which the data base for the wave scatter diagram data is

constructed is long enough to be a reliable basis for design (preferably at least

five years). The occurrence distribution is to be annualized with equal

probability of occurrence for each data point. Each data point is to represent a

sea state of approximately three hours in a continuous time duration of the

database.

(3) Wave directions of head seas and other directions relative to the vessel

heading, including the effects of wind and current, with proper probability

distribution are to be considered, irrespective of the type of mooring system

utilized.

(4) As appropriate, either long-crested seas or short-crested seas with cosine

squared spectral energy spreading in direction are to be considered for various

design issues.

1.3.2.2 Transit

The wind and wave conditions representing the environment for the transit route

from the building or outfitting site (or the shipyard where the conversion

modifications are made) to the project site and the time of the year are to be

determined for the design of a floating installation. As a minimum, the wind speed

and significant wave height of 10-year return period are to be considered, unless a

weather routing plan is to be implemented for the voyage. Seasonal effects on the

design environments as appropriate for the proposed transit duration can be

considered.

In addition to the check on vessel's hull strength during transit, special attention is

to be paid to items such as the flare boom, crane pedestal and process equipment

supports that will be subject to motion-induced loading and/or effects of green

water. Motion-induced loads during transit are to be calculated and the

superstructures and their supports, which are included in the scope of classification,

shall be verified against these loads.

If fitted with an internal turret, special consideration is to be given to bottom

slamming to preclude damage to the turret supports and bearings.

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1.4 Environmental Conditions

1.4.1 General

The environmental conditions for the various design conditions described in 1.3 are

to be submitted with adequate data for the specific site of operation. Statistical data

and mathematical models that describe the range of pertinent expected variations of

environmental conditions are to be employed. A