DNVGL-OS-E402 Edition January 2017

Transcription

1 OFFSHORE STANDARDS DNVGL-OS-E402 Edition January 2017 The content of this service document is the subject of intellectual property rights reserved by ("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, available free of charge from is the officially binding version.

2 FOREWORD DNV GL offshore standards contain technical requirements, principles and acceptance criteria related to classification of offshore units. January 2017 Any comments may be sent by to This service document has been prepared based on available knowledge, technology and/or information at the time of issuance of this document. The use of this document by others than DNV GL is at the user's sole risk. DNV GL does not accept any liability or responsibility for loss or damages resulting from any use of this document.

3 CHANGES CURRENT This document supersedes DNV-OS-E402 Offshore standard for, October 2010 and DNV-DS- E403 Standard for Surface Diving Systems, July 2012 Changes in this document are 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. January 2017, entering into force 1 July 2017 General The following main changes were implemented in this document: Combination of the content of the superseded documents referred above. Updating of (design) references to DNV GL service documents incl. DNV GL rules for classification: Ships. Focusing of the scope of the document on diving systems by removal of content related to diving support vessels/unit arrangements and outer areas. Removing procedural descriptions and requirements related to classification. In addition to the above, the following detail changes were made: Changes - current Ch.2 Sec.2 Life support systems including piping, hoses, valves, fittings, compressors, filters and umbilicals Ch.2 Sec.2 [5.1.4]: Restrict the use of threaded pipe penetrations to max. thread size M30. Ch.2 Sec.2 [8]: Restrict the use of detachable connections to max 25 mm (1 ). Ch.3 Sec.1 Design philosophy and premises Ch.3 Sec.1 [9.1.2]: Removed reference to specific parts of ISO Ch.3 Sec.2 Pressure vessels for human occupancy, gas storage and other purposes Ch.3 Sec.2 [1.6.2], Ch.3 Sec.2 [2.3.10] Guidance note, Ch.3 Sec.2 [4.1.3] and Ch.3 Sec.2 [4.1.3]Guidance note, design life with respect to fatigue to be defined by the designer. Ch.3 Sec.2 [5.1.5]: Added guidance note. Ch.3 Sec.3 Life support systems Ch.3 Sec.3 [5.1.6]: Restrict the use of threaded pipe penetrations to max. thread size M30. Ch.3 Sec.6 Launch and recovery systems Ch.3 Sec.6 [3.2.1]: Text related to safety factors revised to be in line with Ch.2 Sec.6 [3.2.1]. Ch.3 Sec.7 Pipes, hoses, valves, fittings, compressors, filters and umbilicals Ch.3 Sec.7 [4.1.1]: Restrict the use of detachable connections to max 25 mm (1 ). Ch.3 Sec.7 [5.1.4]: Updated and more specific requirements to the compressor/filter pack. Editorial corrections In addition to the above stated changes, editorial corrections may have been made. Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 3

4 CONTENTS Changes current...3 Chapter 1 Introduction... 8 Section 1 General Introduction References... 9 Contents Chapter 2 Surface diving systems...25 Section 1 Design philosophy and premises Introduction Documentation philosophy Safety philosophy Surface diving system philosophy External and internal environmental conditions...31 Section 2 Pressure vessels for human occupancy, gas storage and other purposes Introduction General principles for design of chambers Welded pressure vessels, materials, fabrication and strength Gas cylinders Acrylic plastic windows...45 Section 3 Life support systems including piping, hoses, valves, fittings, compressors, filters and umbilicals Introduction Gas storage Gas distribution and control system Diver s heating and environmental conditioning in chambers Piping systems Hoses Valves Fittings and pipe connections Pressure regulators Compressors for breathing gas systems Purification and filter systems Umbilicals...60 Section 4 Electrical systems Introduction Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 4

5 2 System design Equipment in general Miscellaneous equipment Cables...68 Section 5 Fire prevention, detection and extinction Introduction Fire protection Fire detection and alarm system Fire extinguishing Miscellaneous equipment Section 6 Launch and recovery systems (LARS) Introduction Design principles Strength Section 7 Instrumentation and communication Introduction Instrumentation Communication...85 Section 8 Evacuation systems Introduction Contents Chapter 3 Saturation diving systems Section 1 Design philosophy and premises Introduction Safety philosophy General premises System design principles Diving system arrangement and layout Environmental conditions External and internal system condition Documentation Inspection and testing Marking and signboards Section 2 Pressure vessels for human occupancy, gas storage and other purposes General General principles for design of chambers and bells Welded pressure vessels, materials and fabrication Strength of welded pressure vessels Gas cylinders Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 5

6 6 Acrylic plastic windows Section 3 Life support systems General Gas storage Gas distribution Oxygen systems Piping systems Environmental conditioning in bell and chambers Gas control systems Closed circuit breathing systems (CCBS) Diving crew facilities Section 4 Electrical, instrumentation and communication systems General System design Equipment selection and installation Communication Instrumentation Section 5 Fire prevention, detection and extinction General Fire protection Fire detection and alarm system Fire extinguishing Section 6 Launch and recovery systems General Design principles Strength Section 7 Pipes, hoses, valves, fittings, compressors, filters and umbilicals General Components and hoses for oxygen services Pipes and hoses Valves and pressure regulators Fittings and pipe connections Compressors Purification and filter systems Umbilicals Section 8 Hyperbaric evacuation systems Introduction Contents Appendix A Selection of safety objective Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 6

7 1 Introduction Trigger questions Systematic review/analysis Appendix B Dynamic loads in bell handling systems General Loads on negative buoyant bell Loads on a positive buoyant bell (at surface) Design loads Contents Changes historic Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 7

8 CHAPTER 1 INTRODUCTION SECTION 1 GENERAL 1 Introduction 1.1 Objectives The objectives of this standard are to give criteria and guidance on design, fabrication, installation, testing and commissioning of diving systems Further objectives of this standard are to: a) provide an internationally acceptable standard of safety for diving systems by defining minimum requirements for the design, materials, fabrication, installation, testing, commissioning, operation, repair, and re-qualification b) serve as a technical reference document for classification and verification services c) serve as a technical reference document in contractual matters between purchaser and contractor d) serve as a guideline for designers, purchaser, and contractors. Chapter 1 Section General guidance is provided as to the use and interpretation of the standard and text from IMO code of safety for diving systems, 1995 resolution A.831 (19) is included for reference. In the IMO text, this code is referred to as the code The text from IMO code of safety for diving systems, 1995 resolution A.831 (19) is included as normative reference. 1.2 Scope The scope is defined in each section for the various disciplines and may refer to standards that apply to the discipline in general, such as for electrical systems. In these cases this document only contains requirements that are particular to diving systems, whereas the generic requirements are given in the referred rules, standard or code. The combined requirements shall then constitute the scope Requirements for the diving support vessels, such as the requirements for floatation and positioning ability, are not given in this standard but provided in DNVGL-RU-SHIP Pt.5 Ch Where the code requires that a particular fitting, material, appliance, apparatus, item or type of equipment should be fitted or carried in a system, or that any particular provision should be made, or any procedure or arrangement complied with, the administration may allow alternative arrangements in that system, provided that the administration is satisfied that such alternatives are at least as effective as the requirements of the code. (See IMO code of safety for diving systems Ch.2 design, construction and survey 1.5 equivalents.) This standard is not applicable to SCUBA diving, submersibles including atmospheric diving suits or submarines. Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 8

9 1.3 Application Where reference is made to codes other than DNV GL documents, the valid revision shall be taken as the revision that was current at the date of issue of this standard In case of conflict between requirements of this standard and a reference document, the requirements of this standard shall prevail For use of this standard as basis for classification including the relevant procedural requirements see DNVGL- RU-OU-0375 Rules for classification of diving systems 1.4 Document structure Chapter 1 Section Besides this introduction chapter, this standard consist of two technical chapters: Ch.2 Describing design philosophy and all technical and procedural requirements for surface diving systems Ch.3 Describing design philosophy and all technical and procedural requirements for saturation diving systems General applicable procedural requirements, including documentation and survey and testing are included in the sub-section [1] of the relevant sections both chapters Ch.2 is completed with an appendix providing guidance on the selection of a safety objective Ch.3 is completed with an appendix providing guidance on dynamic loads in bell handling systems. 2 References 2.1 Normative references The latest revisions of the following documents apply as normative references: Table 1 Rules and standards for certification Reference Title DNVGL-RU-SHIP DNVGL-RU-OU DNVGL-ST-0378 Rules for classification: ships Rules for classification: offshore units Standard for offshore and platform lifting appliances Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 9

10 Table 2 Offshore standards Reference Title DNVGL-OS-A101 Safety principles and arrangements DNVGL-OS-D201 Electrical installations DNVGL-OS-D202 Instrumentation, safety and telecommunication systems DNVGL-OS-D301 Fire protection Table 3 Class programme Reference Title Type approval DNVGL-CP-0183 Flexible hoses, non-metallic materials Chapter 1 Section 1 Type approval DNVGL-CP-0184 Flexible hoses with permanently fitted couplings, metallic materials Table 4 Class guidelines Reference DNVGL-CG-0169 Title Quality survey plan for offshore class new building surveys Table 5 Recommended practices Reference Title DNVGL-RP-E403 Hyperbaric evacuation systems Table 6 Other normative references Reference ASME VIII div.1 or div.2 ASME PVHO-1 ASME PVHO-2 ASTM G93-03 API 17E Title ASME boiler and pressure vessel code rules for construction of pressure vessels Safety standard for pressure vessels for human occupancy Safety standard for pressure vessels for human occupancy: in service guidelines Standard practice for cleaning methods and cleanliness levels for materials and equipment used in oxygen-enriched environments Specification for subsea production control umbilicals BS 4778 Quality vocabulary, part 2 quality concepts and related definitions, 1991, British standards institute, London EN EN EN ISO Transportable gas cylinders, condition for filling gases into receptacles, single component gases Transportable gas cylinders, condition for filling gas mixtures into receptacles Pressure regulators for use with medical gases Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 10

11 Reference EN ISO EN ISO ISO 6406 EN EN ISO EN Title Gas cylinders, refillable seamless steel gas cylinders, design, construction and testing, part 1: quenced and tempered steel cylinders with tensile strength less than 1100 MPa Gas cylinders, refillable seamless steel gas cylinders, design, construction and testing, part 2: quenced and tempered steel cylinders with tensile strength greater or equal to 1100 MPa Gas cylinders, seamless steel gas cylinders, periodic inspection and testing Metallic products, types of inspection documents Gas cylinders, refillable seamless steel tubes for compressed gas transport, of water capacity between 150 l and 3000 l, design construction and testing Gas cylinders, periodic inspection and testing, in situ (without dismantling) of refillable seamless steel tubes of water capacity between 150 l and 3000 l, used for compressed gases Chapter 1 Section 1 EN EN ISO/IEC/17065:2012 EN Unfired pressure vessels Respiratory equipment compressed gases for breathing apparatus Conformity assessment, requirements for bodies certifying products, processes and services Welding, basic weld joint details in steel, part 1 pressurized components IMO resolution A.831 (19) Code of safety for diving Systems, 1995 IMO resolution A.692 (17) Guidelines and specifications for hyperbaric evacuation systems, 1991 IMO MSC/circ.645 of 6 June 1994 IMO Res. MSC 149 (77) IMO Res. MSC 307 (88) IMO Res. MSC337 (91) IEC No ISO ISO 9000 ISO ISO 10380, BS 6501 ISO ISO PD 5500: latest amendments Guidelines for vessels with dynamic positioning systems See SOLAS reg. III/6.2.1 (FTP code) Code on noise levels on-board ships International Electro technical Commission's publication No.79-10, and IMO (MODU) code Ch.6 Ergonomic principles in the design of work systems Quality management Guidelines for quality management system documentation Pipework, corrugated metal hoses and hose assemblies Steel and steel products, inspection documents Petroleum and natural gas industries, design and operation of subsea production systems, part 5: subsea control umbilicals Specification for unfired fusion welded pressure vessels Note: see also Appendix C list of sources to assist in obtaining reference documents Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 11

12 2.2 Informative references Table 7 Informative references Reference NORSOK Standard U-100 ISO ISO ISO ISO Manned underwater operations Title Gas cylinders, cylinder valves, specification and type testing Gas cylinders, compatibility of cylinder and valve materials with gas contents, part 3: autogenous ignition test in oxygen atmosphere Part 1: pressure regulators for use with medical gases, part 1: pressure regulators and pressure regulators with flow-metering devices Gas cylinders cylinder valves and type testing Chapter 1 Section 1 (NFPA) Codes SOLAS 1974, Consolidated edition National fire protection agency International convention for the safety of life at sea Guidance note: The latest revision of the DNV GL documents may be found in the publication list at the DNV GL website ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e Terminology and definitions Verbal forms Term shall should may Definition verbal form used to indicate requirements strictly to be followed in order to conform to the document verbal form used to indicate that among several possibilities one is recommended as particularly suitable, without mentioning or excluding others, or that a certain course of action is preferred but not necessarily required verbal form used to indicate a course of action permissible within the limits of the document Note: in the cases where text from the IMO code of safety for diving systems Ch.2. design, construction and survey is used, the IMO use of should shall be interpreted as shall. Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 12

13 2.4 Definitions Term Administration Agreement, by agreement As-built survey Definition The government of the state whose flag a ship or floating structure which carries a diving system is entitled to fly or in which the ship or floating structure is registered (see IMO code of safety for diving systems Ch.2 design, construction and survey 1.3.1) Unless otherwise indicated, accepted/agreed in writing between manufacturer/ contractor and purchaser. When the standard is applied as basis for certification or classification by DNV GL, the terms shall mean approved upfront in writing by DNV GL. Survey of the installed and completed diving system, which is performed to verify that the completed installation work meets the specified requirements, and to document deviations from the original design, if any. Chapter 1 Section 1 Basket Bell Bottle Breathing gases Builder Built in breathing system (BIBS) Category A machinery spaces Chamber Closed bell A divers basket (sometimes known as a stage) is a frame and mesh construction designed to accommodate divers whilst they are lifted in and out of the water A diving bell is a frame incorporating a dome, and including appendages, for transfer of divers between the underwater work site and the deck or the surface chamber (TUP or DDC). In the context of this standard, bell is defined as an open bell/wetbell. (See open bell, closed bell and wet bell) A pressure container for the storage and transport of gases under pressure (see IMO code of safety for diving systems Ch.2 design, construction and survey 1.3.2) All gases and gas mixtures which are used during diving missions respectively during use of breathing apparatus. Depending on the grade of oxygen, complimentary rules may be taken into consideration. The most common breathing gases used for diving are air, nitrox, HeMix, Trimix and pure oxygen. Signifies the party contracted to build a diving system in compliance with this standard A system of gas delivery to masks, located in the decompression chambers, baskets and wet-bells. This system facilitates breathing in the event of a contaminated atmosphere, and allows for the use of therapeutic gases during decompression. BIBS may in rare cases be closed circuit breathing systems (see CCBS definition) but are normally open circuit systems where the exhaled gas is dumped to atmosphere. Those spaces and trunks to such spaces as defined in the international convention for the safety of life at sea, 1974, as amended (See IMO code of safety for diving systems Ch.2 design, construction and survey ) Surface decompression, pressure or compression chambers (see also DDC), hereafter called the chambers, and are pressure vessels for human occupancy. A sealed submersible diving chamber (SDC) that locks on and off the chamber where the divers decompress (DDC). Pressure differentials are retained by way of a closed door sealing the divers in at pressures, elevated or lowered compared to the surrounding pressure. Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 13

14 Term Closed circuit breathing system (CCBS) Commissioning Compact umbilical Compartment Competent body/competent person Compressor Definition A system for supply of breathing gas to the diver and saving of his exhaled gases for re-circulation after scrubbing and replenishing In relation to diving systems, refers to activities which take place after installation and prior to operation, comprising the tests and trials Umbilical consisting of composite bundles of hoses, cables and strength members in a braiding or sheathing Part(s) of a chamber sufficiently large to contain at least one person and which may have an internal pressure different from adjacent compartments In this context defined as a company, organisation or person recognised as fit to carry out specified inspections or tests. The recognition may be by DNV GL or by a statutory agency. A mechanical device that increases the pressure of a gas by reducing its volume. The increase of pressure may be carried out by pistons, screws or diaphragms. A compressor designed with inlet (suction) pressure above atmospheric is defined as booster. Depending on the application medium, purification and/or filter systems may be provided downstream. Chapter 1 Section 1 Construction phase Contractor Control stations Corrosion allowance Demobilised Deck decompression chamber (DDC) All phases during construction, including fabrication, installation, testing and commissioning, up until the installation or system is safe and operable for intended use. In relation to diving systems, this includes procurements, manufacture assembly, rectification, installation, testing, commissioning and repair. A party contractually appointed by the purchaser to fulfil all, or any of, the activities associated with design, construction and operation Normally as defined in reg.3 and referred to in regulation 20, Ch.II-2 of the International Convention for the Safety of Life at Sea. Control stand or control station is a control station in which one or more of the following control and indicator functions are centralized: a) indication and operation of all vital life support conditions, including pressure control b) visual observation, communication systems including telephones, audiorecording and microphones to public address systems c) disconnection of all electrical installations and Insulation monitoring. d) provisions for calibration of and comparison between gas analysing e) indication of temperature and humidity in the inner area f) alarms for abnormal conditions of environmental control systems g) fixed fire detection and fire alarm systems h) ventilation fans i) automatic sprinkler, fire detection and fire alarm systems j) launch and recovery systems, including interlock safety functions k) operation and control of the hyperbaric evacuation system. Extra wall thickness added during design to compensate for any reduction in wall thickness by corrosion (internally and externally) during operation Diving system is stored on shore and requires a full maintenance regime for mobilisation Deck mounted pressure vessel for human occupancy used for decompression Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 14

15 Depth Design Design life Design load Design phase Term Definition The water depth or equivalent pressure to which the diver is exposed at any time during a dive or inside a surface compression chamber or a diving bell (see IMO code of safety for diving systems Ch.2 design, construction and survey 1.3.6) All related engineering to design of the diving system The initially planned time period from initial installation or use until permanent decommissioning of the equipment or system. The original design life may be extended after a re-qualification. For PVHOs see Ch.2 Sec.3, Ch.3 Sec.2. For LARS see Ch.2 Sec.6 and Ch.3 Sec.6. An initial phase that takes a systematic approach to the production of specifications, drawings and other documents to ensure that the diving system meets specified requirements (including design reviews to ensure that design output is verified against design input requirements). See ISO Chapter 1 Section 1 Design temperature, minimum The lowest possible temperature to which the equipment or system may be exposed to during installation and operation, irrespective of the pressure. Environmental as well as operational temperatures shall be considered. Guidance note: For LARS the design temperature is defined in DNVGL-ST-0378 standard for offshore and platform lifting appliances. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--- Design temperature, maximum: Diver heating Divers Diving bell Diving system Diving system (in DNV GL terms) dmax ECU Enriched Air The highest possible temperature to which the equipment or system may be exposed to during installation and operation. Environmental as well as operational temperatures shall be considered. A system for actively heating the divers in the water or in the inner area Personnel subjected to higher ambient pressure than one atmosphere A submersible compression chamber, including its fitted equipment, for transfer of diving personnel under pressure between the work location and the surface compression chamber (see IMO code of safety for diving systems Ch.2 design, construction and survey 1.3.7) The whole plant and equipment necessary for the conduct of diving operations (see IMO code of safety for diving systems Ch.2 design, construction and survey 1.3.8) The whole plant and equipment necessary for safe conduct of diving operations where compression and decompression of divers are taking place Maximum operating depth of the surface diving system. This is the depth corresponding to the maximum pressure for pressurizing divers. (For Classified systems this may be specified in the certificate and data sheet). Environmental control unit. Maintains Temperature, reduces humidity and may include removal of carbon dioxide. Nitrogen oxygen mixtures with elevated oxygen content (see NITROX) Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 15

16 Term Equipment lock Evacuation system Fabrication Fabricator Definition A pressure tight independent lock mounted on the shell of the chamber providing the means for locking in equipment necessary for the divers and the operation of the system (see also medical lock) A system whereby divers under pressure can be safely evacuated from a ship or floating structure to a position where decompression can be carried out (see IMO code of safety for diving systems Ch.2 design, construction and survey 1.3.9) Activities related to the assembly of objects with a defined purpose. In relation to diving systems, fabrication refers to e.g. deck decompression chambers, wet-bells, and pressure vessels for gas storage, environmental control systems, launch and recovery systems etc. The party performing the fabrication (in this context, normally of windows for PVHOs) Chapter 1 Section 1 Failure Fatigue Flag administration Gas Gas containers Guidance notes Handling system Hazard Hazardous areas HAZOP (hazard and operability study) Hydro-test or hydrostatic test An event affecting a component or system and causing one or both of the following effects: loss of component or system function deterioration of functional capability to such an extent that the safety of the installation, personnel or environment is significantly reduced. Cyclic loading causing degradation of the material The maritime administration of a vessel's country of registry See breathing gas Cylinders, bottles and pressure vessels for storage of pressurized gas 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 The plant and equipment necessary for raising, lowering and transporting the diving bell between the work location and the surface compression chamber (see IMO code of safety for diving systems Ch.2 design, construction and survey ) (see launch and recovery system (LARS)) A deviation (departure from the design and operating intention) which could cause damage, injury or other form of loss (chemical industries association HAZOP guide). Those locations in which an explosive gas-air mixture is continuously present, or present for long periods (zone O); in which an explosive gas-air mixture is likely to occur in normal operation (zone 1); in which an explosive gas-air mixture it not likely to occur, and if it does it will only exist for a short time (zone 2). (See IMO code of safety for diving systems Ch.2 design, construction and survey ) The application of a formal systematic critical examination to the process and engineering intentions of new or existing facilities to assess the hazard potential of inadvertent operation or malfunction of individual items of equipment and their consequential effects on the facility as a whole (chemical industries association HAZOP guide) See pressure test Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 16

17 Term Hyperbaric evacuation system (HES) Hyperbaric rescue vessel (HRV) Inner area Inspection Installation (activity) Installation manual (IM) Definition System for evacuating divers under pressure. This includes the hyperbaric evacuation unit (HEU), the launch and recovery and control systems. IMO uses the term hyperbaric evacuation unit (HEU) see above The areas which are inside the chambers. Interconnecting trunks are considered part of the inner area when the door is opened into the chamber. Activities such as measuring, examination, testing, gauging one or more characteristics of a product or service and comparing the results with specified requirements for determine conformity The operations related to installing the equipment, diving system or support structure, e.g. mounting chambers and handling systems etc., including final testing and preparation for operation A document prepared by the contractor to describe and demonstrate that the installation method and equipment used by the contractor will meet the specified requirements and that the results can be verified Chapter 1 Section 1 Launch and recovery system (LARS) Lay-up Life support system Life support systems (in DNV GL terms) Living compartment Living compartment (in DNV GL terms) Load Load effect Load effect factor The system and equipment necessary to launch and recover the divers, the diver s basket or wet-bell to the chambers as well as transport the divers between the surface support unit and the underwater working site, including any guide rope systems and cursor systems A terminology used for diving systems that are out of commission. In this state the diving system may be installed on board or permanently stored on shore. The gas supply, breathing gas system, decompression equipment, environmental control system and equipment required to provide a safe environment for the diving crew in the diving bell and the surface compression chamber under all ranges of pressure and conditions they may be exposed to during diving operations (see IMO code of safety for diving systems Ch.2 design, construction and survey ) The systems comprising gas supply systems, breathing gas systems, pressure regulating systems, environmental control systems, and systems required to provide a safe habitat for the divers, in the basket, the wet-bell and the chamber compartments under normal conditions during diving operation The part of the surface compression chamber which is intended to be used as the main habitation for the divers during diving operations and which is equipped for such purpose (see IMO code of safety for diving systems Ch.2 design, construction and survey ) A compartment which is intended to be used as the main habitation for the divers and which is equipped as such Any action causing stress, strain, deformation, displacement, motion, etc. to the equipment or system Effect of a single load or combination of loads on the equipment or system, such as stress, strain, deformation, displacement, motion, etc. The partial safety factor by which the characteristic load effect is multiplied to obtain the design load effect Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 17

18 Term Lot Main components Manufacture Manufacturer Definition A number of components from the same batch. E.g. same heat, the same heat treatment batch and with the same dimensions. Main components of a diving system include the surface compression chamber, diving bell, handling system and fixed gas storage facilities (see IMO code of safety for diving systems Ch.2 design, construction and survey ) Making of articles or materials, sometimes in larger volumes. In relation to diving systems, refers to activities for the production of pressure vessels, distribution panels and other components, performed under contracts from one or more contractors. 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 Chapter 1 Section 1 Mating device Maximum operating depth Medical lock NDT level NITROX Nominal outside diameter Nominal wall thickness Normal cubic meters Open bell (also known as wet bell) Operation, incidental Operation, normal The equipment necessary for the connection and a disconnection of a diving bell to a surface compression chamber (see IMO code of safety for diving systems Ch.2 design, construction and survey ) Maximum operating depth of the diving system is the depth in metres or feet of seawater equivalent to the maximum pressure for which the diving system is designed to operate (see IMO code of safety for diving systems Ch.2 design, construction and survey ) A pressure tight independent lock mounted on the shell of the chamber providing the means for locking in provisions, medicine and equipment necessary for the divers and the operation of the system (see also equipment lock) The extent and acceptance criteria for the NDT of the components Nitrogen oxygen mixtures with elevated oxygen content (see enriched air) The specified outside diameter. This shall mean the actual outside diameter. The specified non-corroded wall thickness, which is equal to the minimum steel wall thickness plus the manufacturing tolerance (Nm 3 ) is taken as cubic meters of gas at standard conditions of 0 C and bar. A suspended canopy chamber, open at the bottom like a moon pool structure that is lowered underwater to operate as a stage for the divers with the advantage of providing an air pocket for refuge and a space for communication outside the mask/ helmet Conditions that are not part of normal operation of the equipment or system. In relation to diving systems, incidental conditions may lead to incidental pressures. Conditions that arise from the intended use and application of equipment or system, including associated condition and integrity monitoring, maintenance, repairs etc. In relation to diving systems, this should include, start and finish of dives (pre- and post-dive checks), treatment of decompression-related incidents, gas transfer and changing out of consumables. Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 18

19 Term Operations (phase) Pressure, system test Organization Definition The phase when the diving system is being used for the purpose for which it was designed In relation to diving systems, this is the internal pressure applied to the component or system during testing on completion of installation work to test the diving system for tightness (normally performed as hydrostatic testing) Organization means the International Maritime Organization (IMO) (see IMO code of safety for diving systems Ch.2 design, construction and survey ) Out of roundness The deviation of the perimeter from a circle. This can be stated as ovalisation (%), or as local out of roundness, e.g. flattening, (mm). Outer area Those areas of the diving system that are exposed to atmospheric conditions during operation, i.e. outside the inner system and the room or area that surrounds or contains the diving system. Chapter 1 Section 1 Ovalisation Owner The deviation of the perimeter from a circle. This has the form of an elliptic cross section. Signifies the registered owner or manager of the diving system or any other organization or person who has assumed the responsibility for operation of the diving system and who on assuming such responsibility has agreed to take over all the duties and responsibilities. See DNVGL-RU-OU-0101 Ch.1 Sec. 5 [1.2]. Oxygen systems Systems intended for a gas with a higher oxygen percentage than 25 Personal diving equipment Plan approval Planned maintenance system (PMS) Pressure, collapse Pressure control system Pressure, design Pressure regulating system Pressure safety system Equipment carried by the diver on his person including his tools, diving suit, diving helmet and self-contained breathing apparatus with gas bottles. This is normally not included in the diving system specified in the standard Signifies a systematic and independent examination of drawings, design documents or records in order to verify compliance with the rules or statutory requirements. Plan approval will be carried out at the discretion of the Society, which also decides the extent and method of examination. A system for planning and recording of maintenance activities Characteristic resistance against external over-pressure In relation to diving systems, this is the system for control of the pressure in the various systems, comprising the pressure regulating system, pressure safety system and associated instrument and alarm systems In relation to diving system assemblies, this is the maximum internal pressure during normal operation, referred to a specified reference point, to which the component or system section shall be designed. The design pressure shall take account of the various pressurised components in the adjoining systems, and their relative design pressures. In relation to diving systems, this is the system which ensures that, irrespective of the upstream pressure, a set pressure is maintained downstream (at a given reference point) for the component The system which, independent of the pressure regulating system, ensures that the allowable set pressure is not exceeded Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 19

20 Term Pressure test Pressure vessel Purchaser Purification and filter systems Quality assurance (QA) Definition The hydrostatic pressure test initially performed at the manufacturer of the pressure vessel in accordance with requirements in the design code A container capable of withstanding an internal maximum working pressure greater than or equal to 1 bar (see IMO code of safety for diving systems Ch.2 design, construction and survey ) The owner or another party acting on his behalf, who is responsible for procuring materials, components or services intended for the design, construction, installation or modification of a diving system Purification and filter systems are used to remove contaminants from breathing gases after compression has taken place Planned and systematic actions necessary to provide adequate confidence that a product or service will satisfy given requirements for quality Chapter 1 Section 1 Quality plan (QP) Quality system Reliability Re-qualification Resistance Risk Risk reduction measures Safety objectives The document setting out the specific quality practices, resources and sequence of activities relevant to a particular product, project or contract. A quality plan usually makes reference to the part of the quality manual applicable to the specific case. Signifies both the quality management system and established production and control procedures The probability that a component or system will perform its required function without failure, under stated conditions of operation and maintenance and during a specified time interval The re-assessment of a design due to modified design premises and or sustained damage The capability of a structure, or part of a structure, to resist load effects The qualitative or quantitative likelihood of an accident or unplanned event occurring, considered in conjunction with the potential consequences of such a failure. In quantitative terms, risk is the quantified probability of a defined failure mode times its quantified consequence. Those measures taken to reduce the risks to the operation of the diving system and to the health and safety of personnel associated with it or in its vicinity by: a) reduction in the probability of failure b) mitigation of the consequences of failure. Guidance note: The usual order of preference of risk reduction measures is: a) inherent safety b) prevention c) detection d) control e) mitigation f) emergency response. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--- The safety goals for the construction, operation and decommissioning of the diving system including acceptance criteria for the level of risk acceptable to the owner Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 20

21 Saturation diving Term Self-propelled hyperbaric lifeboat (SPHL) Significant wave height Specified minimum tensile strength Specified minimum yield stress Definition Once a diver becomes saturated with the gases that make decompression necessary, the diver does not need additional decompression. When the blood and tissues have absorbed all the gas they can hold at that depth, the time required for decompression becomes constant. As long as the depth is not increased, additional time on the bottom is free of any additional decompression. See HEU [2.3.55] When selecting the third of the number of waves with the highest wave height, the significant wave height is calculated as the mean of the selection The minimum tensile strength prescribed by the specification or standard under which the material is purchased The minimum yield stress prescribed by the specification or standard under which the material is purchased Chapter 1 Section 1 Statement of compliance Submersible decompression chamber (SDC) Suitable breathing gas Supplementary requirements Surface compression chamber Survey planning document T op Transfer compartment Transferable diving system Ultimate tensile strength A statement or report signed by a qualified party affirming that, at the time of assessment, the defined phase, or collection of activities, met the requirements stated by the customer Closed bell A gas or gas mixture that is breathable to divers for the pressure and duration they are exposed to it Requirements for material properties of component that are additional to the basic requirements, and that are intended to apply to components used for specific applications A pressure vessel for human occupancy with means of controlling the pressure inside the chamber (see IMO code of safety for diving systems Ch.2 design, construction and survey 1.3.5) As described in Ch.3 Sec.1 [3.1] document describing the diving system and the requirements to survey and testing throughout the lifetime of the diving system Maximum operation time, i.e. the time from start of pressurization of the diver, until the diver is back to atmospheric conditions Compartment that is intended to be used for a lock-in or -out operation of divers between other compartments or outer area. Also known as TUP (transfer under pressure). The diving system should be capable of allowing the safe transfer of a person under pressure from the diving bell to the surface compression chamber (and vice versa). (See IMO code of safety for diving systems Ch.2 design, construction and survey 2.2.7) A diving system designed to be easily transferable in one or more units and which may be installed on-board a ship, barge or offshore platform for a short period of time not exceeding one year. A transferable diving system may be assembled from different units into a particular configuration suitable for a specific working operation. The measured ultimate tensile strength Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 21

22 Term Umbilical Umbilical (in DNVGL terms) Verification Wet bell Work Definition The link between the diving support unit and the diving bell and may contain surveillance, communication and power supply cables, breathing gas and hot water hoses. The hoisting and lowering strength member may be part of the umbilical. (See IMO code of safety for diving systems Ch.2 design, construction and survey ) A link between support vessel and the divers, or the diving wet-bell, which may contain gas hoses, hot water hose, power supply cables and communication cables 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 See open bell All activities to be performed within relevant contract(s) issued by owner, builder or manufacturer Chapter 1 Section 1 Working weight Yield Stress Of the basket or wet-bell shall be taken as the maximum weight of the fully equipped basket or wet-bell, including each fully equipped diver (150 kg for SAT and 200 kg for Surface). The load from this weight applies to: a) launch and recovery in air b) launch and recovery submerged, combining the maximum negative buoyancy of the wire rope, umbilical and basket or wet-bell at maximum operating depth. The measured yield tensile stress Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 22

23 2.5 Abbreviations and symbols Abbreviation AE Acoustic emission testing API American Petroleum Institute ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials AUT Automatic ultrasonic testing BS* British Standard C-Mn Carbon manganese Definition Chapter 1 Section 1 CE CRA DP DSV EBW ET FMEA HAZ HAZOP HFW HPIC IACS IM IMO ISO KV LBW MPQT MPS MSA NACE NDT NPD P Conformité Européene (European Conformity) Corrosion resistant alloy Dynamic positioning Diving support vessel Electronic beam welded Eddy current testing Failure mode effect analysis Heat affected zone Hazard and operability study High frequency welding Hydrogen pressure induced cracking International Association of Class Societies Installation manual International Maritime Organisation International Organisation for Standardisation Charpy value Laser beam welded Manufacturing procedure qualification test Manufacturing procedure specification Manufacturing survey arrangement National Association of Corrosion Engineers Non-destructive testing alternatively NDE is used with the same meaning Norwegian Petroleum Directorate production Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 23

24 Abbreviation Q QA QC QP QRA ROV UTS WPS YS Qualification Quality assurance Quality control Quality plan Quantitative risk analysis Remotely operated vehicle Ultimate tensile strength Welding procedure specification Yield stress Definition Chapter 1 Section 1 *Note: now PD: public document 2.6 Symbols A = cross section area D = nominal outside diameter = greatest measured inside or outside diameter D max D min D i E f 0 = smallest measured inside or outside diameter = D-2t nom = nominal internal diameter = young s modulus = ovality, H H s ID O OD T T max T min T nom = wave height = significant wave height = nominal inside diameter = out of roundness, D max - D min = nominal outside diameter = operating temperature = maximum design temperature = minimum design temperature = nominal thickness Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 24

25 CHAPTER 2 SURFACE DIVING SYSTEMS SECTION 1 DESIGN PHILOSOPHY AND PREMISES 1 Introduction 1.1 Objectives The objectives of this section are to present the safety philosophy applied in this chapter, to identify and provide a basis for definition of relevant system design characteristics. These are, key issues required for design, construction, operation and re-qualification of surface diving systems This section also refers to minimum requirements for documentation for design, manufacture, installation and some operational aspects. Chapter 2 Section Scope The scope of this section is to outline the requirements for planning and documenting system philosophy, safety philosophy and quality management. 1.3 Marking and signboards Labels (name plates) of flame retardant material bearing clear and indelible markings shall be placed so that all equipment necessary for operation (valves, detachable connections, switches, warning lights etc.) can be easily identified. The labels shall be permanently fixed. 2 Documentation philosophy 2.1 General This sub-section specifies the general requirements for documentation during diving system design, manufacturing, fabrication, installation, commissioning and operation In accordance with quality system requirements, design output shall be documented and expressed in terms that can be verified and validated against design input requirements. The supplier shall establish and maintain documented procedures to control all documents and data All documentation requirements shall be reflected in a document register. The documentation shall cover design, manufacturing, fabrication, installation and commissioning. As a minimum, the register shall reflect activities from the start of design to operation of the diving system The documentation shall be submitted to the relevant parties for acceptance, verification or information as agreed in ample time before start of fabrication. Documentation pertaining to the system philosophy, concept and manufacturing procedure specification, shall be submitted for approval and information at the start of the project to enable systematic review Verified documentation shall be available at the work site before manufacturing commences. Offshore standards, DNVGL-OS-E402. Edition January 2017 Page 25