RULES FOR CLASSIFICATION
Offshore units
DNVGL-RU-OU-0375 Edition July 2019
Diving systems
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DNV GL AS FOREWORD
DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.
© DNV GL AS July 2019
Any comments may be sent by e-mail to [email protected]
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. Unless otherwise stated in an applicable contract, or following from mandatory law, the liability of DNV GL AS, its parent companies and subsidiaries as well as their officers, directors and employees ("DNV GL") for proved loss or damage arising from or in connection with any act or omission of DNV GL, whether in contract or in tort (including negligence), shall be limited to direct losses and under any circumstance be limited to 300,000 USD. CHANGES – CURRENT
This document supersedes the July 2017 edition of DNVGL-RU-OU-0375. Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter, section or subsection, normally only the title will be in red colour.
Changes July 2019, entering into force 1 January 2020
Topic Reference Description
Substitute selected definitions Ch.1 Sec.1 Selected definitions and terms have been substituted by and terms to those defined by references to DNVGL-CG-0550. This also applies to Ch.1 Sec.2
DNVGL-CG-0550 and to Ch.2. Changes - current
Updates to inspection and App.B Over pressure tests are now explicitly not accepted for the testing requirements service inspections of pressure vessels.
Ch.3 Sec.2 Removal of static load testing of the LARS at renewal. It was not possible to fully ascertain the condition of the LARS after completion of the test. Further the test had the possibility to increase a non detected damage. Regular inspections (including NDT) of condition shall now be included within the PMS based upon OEM guidance.
Removal of leak testing measured through pressure drop. This test provided a level of third party certification toward ensuring excessive helium use was avoided and was based upon contracting practices that are no longer common. Testing based on a safety level shall be implemented within the PMS system. A certificate based upon the existing testing may be requested where this may be useful, but is no longer a requirement.
Removal of set schedules for pressure vessel testing which shall now be based upon the pressure vessel code (default table based upon ISO). Over pressure tests (hydro and pneumo) with the exception of volume expansion are no longer accepted as a method of confirming condition in service.
The inspections for view ports have been revised to better support the ASME PVHO code and required roles/reporting.
Buoyancy check for the bell may now be based upon the properties of the buoyancy materials, allowance for the use of a test block is also now supported.
App.B Removal of pressure vessel testing every five years and reverting to the ISO requirement of every ten years. For gas bottles in service underwater this is changed from 2 years to 10 years. The earlier testing frequency was not addressing the expected degradation (corrosion) and visual inspection is adequate for that purpose.
The earlier appendix B has been deleted as it was more of a guidance document than rules. It was also not commonly used. appendix C Pressure containing equipment is now appendix B.
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DNV GL AS Topic Reference Description
Use of PMS or other auditable Ch.3 Sec.1 The use of a PMS system as a basis to ensure continued good items to focus testing, condition of a diving system is now mandatory. Requirements inspection and to facilitate are based upon existing practice for ships/offshore units. survey planning. Ch.3 Sec.2 The survey planning document is now explaining the scope of the system and is the basis for approving the content of the PMS system. It shall also demonstrate OEM requirements, procedures used during maintenance and testing as well as the link to the FMEA.
Only annual scope listed. Inspection cycles for equipment will now vary based upon the equipment and design standard so while larger inspections are still required their timing shall be Changes - current agreed within the survey planning document.
Ch.3 Sec.2 Scope for the PMS is based on requirements that were published in the now withdrawn DNVGL-RP-E403. Additional system specific requirements added referening OEM instructions and failure mode effect analysis (FMEA).
Editorial corrections
In addition to the above stated changes, editorial corrections may have been made.
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DNV GL AS CONTENTS
Changes – current...... 3
Chapter 1 Principles and procedures for classification...... 8 Contents Section 1 General...... 8 1 Introduction...... 8 1.1 Objective...... 8 1.2 Scope...... 8 1.3 Application...... 8 1.4 Organisation of this document...... 9 2 References...... 9 2.1 Normative references...... 9 2.2 Informative references...... 12 2.3 Terminology and definitions...... 12 2.4 Abbreviations and symbols...... 19 Section 2 Principles and procedures for classification...... 23 1 Introduction...... 23 2 Classification principles...... 23 2.1 The classification concept...... 23 2.2 Statutory certification...... 23 3 Classification scope and notations...... 24 3.1 Scope...... 24 3.2 Class notations...... 24 4 Assignment of class...... 25 4.1 Assignment of class - new systems...... 25 4.2 Survey during construction...... 27 4.3 Assignment of class - existing systems...... 29 4.4 Classification certificate...... 30 5 Retention of class...... 30 5.1 Conditions of retention of class...... 30 5.2 Damage and repairs...... 30 5.3 Withdrawal of class...... 31 6 Certification of materials, components and systems...... 31 6.1 Introduction...... 31 6.2 Type approval...... 31 7 Legal provisions...... 31
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DNV GL AS Chapter 2 Design, construction and certification provisions...... 32 Section 1 Surface diving systems...... 32 1 Introduction...... 32
2 Technical requirements...... 32 Contents 3 Documentation requirements...... 32 4 Survey and testing requirements...... 32 4.1 General...... 32 4.2 Survey and testing requirements during and after installation...... 32 5 Certification requirements...... 32 5.1 General...... 32 5.2 Launch and recovery systems...... 33 5.3 Component certification...... 33 Section 2 Saturation diving systems...... 36 1 Introduction...... 36 2 Technical requirements...... 36 3 Documentation requirements...... 36 4 Survey and testing requirements...... 36 4.1 General...... 36 4.2 Survey and testing requirements during and after installation...... 36 5 Certification requirements...... 36 5.1 General...... 36 5.2 Launch and recovery systems...... 36 5.3 Component certification...... 37
Chapter 3 Classification in operation...... 40 Section 1 Principles for surveys...... 40 1 Introduction...... 40 1.1 General...... 40 1.2 Other codes...... 40 2 Survey execution...... 40 2.1 General...... 40 2.2 Introduction...... 40 3 Diving system planned maintenance system...... 41 3.1 General...... 41 3.2 Approval process...... 41 4 Out of service...... 44 Section 2 Periodical surveys...... 45
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DNV GL AS 1 Survey planning document...... 45 2 Planned maintenance system - PMS...... 46 3 Annual survey...... 47 3.1 Annual audit of diving system planned maintenance system - DSPMS...... 47 3.2 Visual Inspection...... 48 3.3 Test requirements...... 52 Contents 3.4 LARS...... 56 4 Surface diving systems...... 56 4.1 Annual survey...... 56 4.2 Testing...... 56
Appendix A List of sources to assist in obtaining reference documents (informative)...... 57 1 General...... 57
Appendix B Pressure containing equipment summary.... 59 1 General...... 59 1.1 First year periodic survey...... 59 1.2 Second year periodic survey...... 59 1.3 10-year periodic survey...... 59
Changes – historic...... 62
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DNV GL AS CHAPTER 1 PRINCIPLES AND PROCEDURES FOR CLASSIFICATION
SECTION 1 GENERAL Section 1 1 Introduction
1.1 Objective This publication presents DNV GL rules for classification: Diving systems, the terms and procedures for assigning and retaining classification, including listing of the applicable technical references to be applied for classification. Chapter 1 1.2 Scope
1.2.1 These rules give technical and procedural requirements for classification of complete diving systems, including the certification of components and materials to be used.
1.2.2 The scope of classification includes: — certification of system components — plan approval and survey of the diving system.
1.2.3 These rules do not include vessel specific requirements relevant to diving support vessels, as covered by DNVGL-RU-SHIP. Guidance note: Notwithstanding the above, these rules do apply to the diving system as installed on vessels with the class notation Diving support vessel as described in DNVGL-RU-SHIP Pt.5 Ch.10
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1.2.4 The designer or builder may as an alternative to comply with the requirements given in these rules, submit evidence that the topics covered in these rules are accepted by the national authorities. Guidance note: National authorities may have requirements in addition to the requirements stipulated in these rules. Compliance with the requirements in these rules will not automatically result in compliance with requirements stipulated by the national authorities.
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1.3 Application
1.3.1 These rules apply to certification and classification during the design, construction and operation of diving systems.
1.3.2 These rules are intended for diving systems used in the petroleum and natural gas industries. For application in other industries, special considerations may need to be agreed by the parties to the contract and or involved statutory regulators.
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DNV GL AS Guidance note: Additional requirements for the diving system may be applicable due to the statutory requirements given in certain geographic areas, or onboard ships flying certain flags (see also Sec.2 [2.2]) .
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1.3.3 These rules apply to both transferable and permanent installed diving systems as located on and
operated from a ship, barge, mobile offshore platform, fixed offshore installation or an onshore site (in the Section 1 latter case e.g. for training and research purposes).
1.3.4 These rules do not apply to submersibles or atmospheric diving systems (ADS such as JIM and NEWT suits) as these are covered by DNV GL rules for classification: Underwater technology (RU-UWT).
1.4 Organisation of this document
Following this introduction section, this document is structured as follows: Chapter 1 — Sec.2 describes the classification principles and procedures. — Ch.2 describes the design, construction and certification provisions as required for classification of surface and saturation diving systems (in respectively Ch.2 Sec.1 and Ch.2 Sec.2). — Ch.3 provides the procedural and inspection requirements as applicable for diving systems in operation. The document is completed with two supportive appendixes: — App.A is a list of sources to assist in obtaining reference documents. — App.B summarizes testing and inspection requirements on pressure containing equipment.
2 References
2.1 Normative references The latest revisions of the following documents apply as normative references:
Table 1 Rules and standards for classification
Document code Title
DNVGL-CG-0550 Maritime services
DNVGL-RU-OU Rules for classification: Offshore units
DNVGL-RU-SHIP Rules for classification: Ships
DNVGL-ST-0378 Standard for offshore and platform lifting appliances
Table 2 Offshore standards
Document code 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
DNVGL-OS-E402 Diving systems
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DNV GL AS Table 3 Class programmes
Document code Title
DNVGL-CP-0183 Flexible hoses - Non-metallic materials
DNVGL-CP-0184 Flexible hoses with permanently fitted couplings - Metallic materials Section 1 Table 4 Recommended practices
Document code Title
DNV-RP-E403 Hyperbaric Evacuation Systems
Table 5 Other normative references Chapter 1 Document code Title
ASME VIII div.1 or div.2 ASME boiler and pressure vessel code, rules for construction of pressure vessels
ASME PVHO-1 Safety standard for pressure vessels for human occupancy
ASME PVHO-2 Safety standard for pressure vessels for human occupancy: in service guidelines
ASTM G93-03 Standard practice for cleaning methods and cleanliness levels for materials and equipment used in oxygen-enriched environments
API 17E Specification for subsea production control umbilicals
BS 4778 Quality vocabulary, part 2: quality concepts and related definitions, 1991, British Standards Institute, London
EN 13096 Transportable gas cylinders, condition for filling gases into receptacles, single component gases
EN 13306 Maintenance terminology
EN 13099 Transportable gas cylinders, condition for filling gas mixtures into receptacles
EN 15628 Qualification of maintenance personnel
EN 1708-1 Welding, basic weld joint details in steel, part 1: pressurized components
EN 837-1 Pressure gauges part 1: bourdon type pressure gauges Dimensions, metrology, requirements and testing
EN ISO 10297 Gas cylinders cylinder valves specification and type testing
EN ISO 15001 Anasthetic and respiratory equipment compatibility with oxygen
EN ISO 10524-1 Pressure regulators for use with medical gases
EN ISO 9809-1 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
EN ISO 9809-2 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
EN 10204 Metallic products, types of inspection documents
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DNV GL AS Document code Title
EN ISO 11120 Gas cylinders, refillable seamless steel tubes for compressed gas transport, of water capacity between 150 l and 3000 l, design construction and testing
EN 16753 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 Section 1 EN 13445 Unfired pressure vessels
EN ISO 12021 Respiratory equipment compressed gases for breathing apparatus
IEC no.79-10 International Electro Technical Commission's publication no.79-10, and IMO MODU code Ch.6
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 Chapter 1
IMO MSC.1/Circ.1580 (16 Guidelines for vessels and units with dynamic positioning (DP) systems June 2017)
IMO resolution MSC 149 (77) See SOLAS regulations III/6.2.1
IMO resolution MSC 307 (88) FTP code International Code for Application of Fire Test Procedures
IMO resolution MSC337 (91) Code on noise levels on-board ships
ISO 4309 Cranes - Wire ropes - Care and maintenance, inspection and discard
ISO 18119 Gas cylinders- Seamless steel and seamless aluminium-alloy gas cylinders and tubes _ Periodic inspection and testing
ISO 6385-2004 Ergonomic principles in the design of work systems
ISO 9000 Quality management
ISO 10013 Guidelines for quality management system documentation
ISO 10380, BS 6501 Pipework, corrugated metal hoses and hose assemblies
ISO 10474 Steel and steel products, inspection documents
ISO 13628-5 Petroleum and natural gas industries, design and operation of subsea production systems, part 5: subsea control umbilicals
ISO/IEC/17065:2012 Conformity assessment, requirements for bodies certifying products, processes and services
PD 5500:2009 + latest Specification for unfired fusion welded pressure vessels amendments
Note: see App.A list of sources to assist in obtaining reference documents.
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DNV GL AS 2.2 Informative references
2.2.1 General
Table 6 Informative references
Document code Title Section 1
ISO 10297 Gas cylinders - cylinder valves - specification and type testing
ISO 10524-1 Pressure regulators for use with medical gases - part 1: pressure regulators with flow- metering devices
ISO 11114-3 Gas cylinders - compatibility of cylinders and valve materials with gas contents - part 3: autogenous ignition test in oxygen atmosphere Chapter 1 NFPA codes National Fire Protection Agency codes
NORSOK Standard U-100 Manned underwater operations
SOLAS 1974 Consolidated International Convention for the Safety of Life at Sea edition
2.2.2 Survey related The following references may be used as guidance for conducting surveys: a) Diving Safety Memorandum issued by the Health and Safety Executive in the U.K. b) International Marine Contractors Association, IMCA/AODC, guidance notes, especially D 018 and D 024 c) IMO code of safety for diving systems adopted by IMO resolution A.831(19) on 23. November 1995 d) IMO guidelines for hyperbaric evacuation (IMO resolution A.692(17)) e) Instructions to classification Societies by Maritime Authorities f) Merchant shipping notices, issued by the Department of Transport in the U.K. g) Canada-Newfoundland and Labrador Offshore Area Diving Operations Safety Transitional Regulations (SOR/2015-5) h) NORSOK U-100 manned underwater operations i) Norwegian Maritime Directorate regulation of 19 April 1984 No.940 j) Canada-Nova Scotia offshore area diving operations safety transitional regulations SOR/2015-6 k) Regulations pertaining to manned underwater operations in the petroleum activity, by NPD l) SI 1997 no.2776 The diving at work regulations 1997.
2.3 Terminology and definitions
2.3.1 Definition of verbal forms
Term Definition
shall verbal form used to indicate requirements strictly to be followed in order to conform to the document
should verbal form used to indicate that among several possibilities one is recommended as particularly suitable, without mentioning or excluding others
may verbal form used to indicate a course of action permissible within the limits of the document
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DNV GL AS 2.3.2 Definition of terms
Term Definition
administration 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) Section 1
as-built survey 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
basket 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 Chapter 1 bottle 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)
builder signifies the party contracted to build a diving system in compliance with the Society's rules
certificate a document confirming compliance with the Society's rules or with other rules and regulations for which the Society has been authorized to act
chamber surface decompression, pressure or compression chambers, (see DDC), hereafter called the chambers, and are pressure vessels for human occupancy
class in the context of these rules, class is assigned to and will be retained by the diving system complying with applicable requirements of the Society's rules
class certificate Certificate confirming compliance with the Society's Rules as applicable and at the time of Survey.
classification A service which comprises the development and maintenance of independent technical standards for Units – Class Rules and standards, and to verify compliance with the Rules and standards throughout the Unit's life. The extent of and methods for verifying compliance will be decided by the Society to establish reasonable assurance that the relevant Rules are complied with.
closed bell 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.
closed circuit breathing system (CCBS) a system for supply of breathing gas to the diver and saving of his exhaled gases for re-circulation after scrubbing and replenishing
commissioning in relation to diving systems, refers to activities which take place after installation and prior to operation, comprising the tests and trials
competent body/competent person 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.
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DNV GL AS Term Definition
compressor 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 shall be entitled as booster. Depending on the application medium, purification and/or filter systems may be provided downstream. Section 1 construction phase 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.
contractor a party contractually appointed by the Purchaser to fulfil all, or any of, the activities associated with design, construction and operation
customer signifies the party who has requested the Society's service Chapter 1
demobilised diving system is stored on shore and requires a full maintenance regime for mobilisation
depth 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)
design all related engineering to design of the diving system
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.
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design temperature, maximum 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.
designer signifies a party who creates documentation submitted to the Society for approval or information
divers personnel subjected to higher ambient pressure than one atmosphere
diving bell 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)
diving system 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). In DNV GL terms the whole plant and equipment necessary for safe conduct of diving operations where compression and decompression of divers are taking place
dmax 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).
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DNV GL AS Term Definition
documentation Drawings, descriptions, calculations, reports, procedures, certificates and similar information describing e.g. the design, installation, testing, operation, maintenance or status of an object.
evacuation system 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, Section 1 (see IMO code of safety for diving systems Ch.2 design, construction and survey 1.3.9)
fabrication 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.
fabricator the party performing the fabrication (in this context, normally of windows for PVHOs) Chapter 1
failure 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.
flag administration the maritime administration of a vessel's country of registry
gas see breathing gas
gas containers cylinders, bottles and pressure vessels for storage of pressurized gas
guidance notes 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
handling system 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 1.3.10), (see launch and recovery system (LARS))
hazard a deviation (departure from the design and operating intention) which could cause damage, injury or other form of loss (Chemical Industries Association HAZOP guide)
hazardous areas 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 1.3.11)
hazard and operability study (HAZOP) 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)
hydro-test or hydrostatic test see pressure test
hyperbaric evacuation system (HES) system for evacuating divers under pressure. This includes the hyperbaric evacuation unit (HEU), the launch and recovery and control systems.
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DNV GL AS Term Definition
hyperbaric rescue vessel (HRV) IMO uses the term hyperbaric evacuation unit (HEU), see above
inner area the areas which are inside the chambers. Interconnecting trunks are considered part of the inner area when the door is opened into the chamber.
inspection activities such as measuring, examination, testing, gauging one or more
characteristics of a product or service and comparing the results with specified Section 1 requirements for determine conformity
installation (activity) 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
installation manual (IM) 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
launch and recovery system (LARS) 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
lay-up 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.
life support system 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 1.3.12)
life support systems (in DNV GL terms) 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
load any action causing stress, strain, deformation, displacement, motion, etc. to the equipment or system
manufacture 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.
manufacturer signifies the entity that manufactures the material or product, or carries out part production that determines the quality of the material or product, or does the final assembly of the product
maximum operating depth 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 1.3.16)
open bell (also known as wet bell) 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
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DNV GL AS Term Definition
operations (phase) the phase when the diving system is being used for the purpose for which it was designed
organization the International Maritime Organization (IMO), (see IMO code of safety for diving systems Ch.2 design, construction and survey 1.3.17)
owner signifies the registered owner or manager of the diving system or any other Section 1 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
oxygen systems systems intended for a gas with a higher oxygen percentage than 25
plan approval signifies a systematic and independent examination of drawings, design documents or records in order to verify compliance with the rules or statutory
requirements. Plan approval will be carried out at the discretion of the Society, Chapter 1 which also decides the extent and method of examination.
planned maintenance system (PMS) s system for planning and recording of maintenance activities
pressure control system 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
pressure regulating system 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
pressure safety system the system which, independent of the pressure regulating system, ensures that the allowable set pressure is not exceeded
pressure test the hydrostatic pressure test initially performed at the manufacturer of the pressure vessel in accordance with requirements in the design code
pressure system test 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
pressure vessel 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 1 3.18)
Product declaration see DNVGL-CG-0550 Sec.3 [2.4]
purchaser 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 purification and filter systems are used to remove contaminants from breathing gases after compression has taken place
quality assurance (QA) planned and systematic actions necessary to provide adequate confidence that a product or service will satisfy given requirements for quality
quality plan (QP) 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.
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DNV GL AS Term Definition
quality system signifies both the quality management system and established production and control procedures
rules all requirements adopted by the appropriate approval body as the basis for classification
safety objectives the safety goals for the construction, operation and decommissioning of the Section 1 diving system including acceptance criteria for the level of risk acceptable to the owner
saturation diving 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. Chapter 1
self-propelled hyperbaric lifeboat see hyperbaric evacuation system (HES) (SPHL)
shipyard signifies the party contracted to build a vessel in compliance with the Society's rules
significant wave height 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.
Society the Society signifies DNV GL
statement of compliance A document confirming compliance with specified requirements for which the Society has not been authorised to act. Compliance is confirmed on the date as given in the statement.
statutory certification A service with the intention of confirming compliance with regulatory codes and regulations - in agreement with relevant Flag Administrations.
surface compression chamber 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)
survey signifies a systematic and independent examination of a diving system, materials, components or systems in order to verify compliance with the rules and/or statutory requirements. Surveys will be carried out on the vessel, at the construction or repair site as well as at sub-suppliers and other locations at the discretion of the Society, which also decides the extent and method of control
survey planning document as described in Ch.3 Sec.2 [1] document describing the diving system and the requirements to survey and testing throughout the lifetime of the diving system
Top maximum operation time, i.e. the time from start of pressurization of the diver, until the diver is back to atmospheric conditions
transferable diving system 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
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DNV GL AS Term Definition
umbilical 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 1.3.19).
In DNV GL terms a link between support vessel and the divers, or the diving Section 1 wet bell, which may contain gas hoses, hot water hose, power supply cables and communication cables
verification a service that signifies a confirmation through the provision of objective evidence (analysis, observation, measurement, test, records or other evidence) that specified requirements have been met
vessel Any object designed for transportation or special operations on water. Chapter 1 wet bell see open bell
witnessing signifies attending tests or measurements where the surveyor verifies compliance with agreed test or measurement procedures
2.4 Abbreviations and symbols
2.4.1 Abbreviations
Abbreviation Description
AE acoustic emission testing
ADS atmospheric diving systems
AoM approval of manufacturers
API American Petroleum Institute
ASME American Society of Mechanical Engineers
ASTM American Society for Testing and Materials
AUT automatic ultrasonic testing
BIBS built in breathing system
BS* British standard
CC condition of class
CCBS closed circuit breathing system
CE Conformité Européene (European Conformity)
CMMS computer maintenance management system
C-Mn carbon manganese
CRA corrosion resistant alloy
DSCBMSA diving system condition based maintenance survey arrangement
DDC deck decompression chamber
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DNV GL AS Abbreviation Description
DP dynamic positioning
DSPMS diving system planned maintenance system
DSPMS RCM diving system planned maintenance reliability centred
EBW electronic beam welded Section 1
ECU environmental conditioning unit
ET eddy current testing
FMEA failure mode effect analysis
HAZ heat affected zone
HAZOP hazard and operability study Chapter 1
HES hyperbaric evacuation system
HFW high frequency welding
HPIC hydrogen pressure induced cracking
HRV hyperbaric rescue vessel
IACS International Association of Class Societies
IM installation manual
IMO International Maritime Organisation
ISO International Organisation for Standardisation
ITP inspection and test plan
JIM trade name for a 1 bar armored diving suit
KV charpy value
LARS launch and recovery system
LBW laser beam welded
MAWP maximum allowable working pressure
MO memo to owners
MPQT manufacturing procedure qualification test
MPS manufacturing procedure specification
MS memo to owners
MSA manufacturing survey arrangement
MVI maintenance viewport inspector
NACE National Association of Corrosion Engineers
NEWT trade name for a 1 bar armored diving suit
NDT non-destructive testing alternatively NDE is used with the same meaning
NPD Norwegian Petroleum Directorate
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DNV GL AS Abbreviation Description
OEM original equipment maker
OVI operational viewport inspector
P production
PC product certificate Section 1
PD public document
PMS planned maintenance system
PTR product test report
PVHO pressure vessel for human occupancy
Q qualification Chapter 1
QA quality assurance
QC quality control
QP quality plan
QRA quantitative risk analysis
SAT saturation
SDC submersible diving chamber
SPD survey planning document
SPHL self-propelled hyperbaric lifeboat
TA type approval
TAC type approval certificate
TR test report
TP test pressure
TUP transfer under pressure
SF safety factor
ROV remotely operated vehicle
PV pressure vessels
UTS ultimate tensile strength
WPS welding procedure specification
YS yield stress
*Note: now PD – public document
2.4.2 Symbols A = cross section area D = nominal outside diameter Dmax = greatest measured inside or outside diameter
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DNV GL AS Dmin = smallest measured inside or outside diameter Di = D-2tnom = nominal internal diameter E = oung’s modulus f = 0 ovality,
H = wave height Section 1 Hs = significant wave height ID = nominal inside diameter
O = out of roundness, Dmax - Dmin OD = nominal outside diameter T = operating temperature Tmax = maximum design temperature
Tmin = minimum design temperature Chapter 1 T nom = nominal thickness
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DNV GL AS SECTION 2 PRINCIPLES AND PROCEDURES FOR CLASSIFICATION
1 Introduction General principles and procedures applicable for classification are described in DNVGL-RU-OU-0101 Ch.1. This section provides specific requirements applicable for classification of diving systems and shall be read as
a supplement to the above referred rules. Section 2
2 Classification principles
2.1 The classification concept
2.1.1 Introduction Classifciation is a service which comprises the development and maintenance of independent technical standards for Units – Class Rules and standards, and to verify compliance with the Rules and standards Chapter 1 throughout the Unit's life. The extent of and methods for verifying compliance will be decided by the Society to establish reasonable assurance that the relevant Rules are complied with.
2.1.2 In general, these rules and the referred standards cover requirements for the availability and the safety of the diving system.
2.1.3 For the assignment of class see [4], for the retention of class see [5].
2.1.4 Applicable rules These rules and the referred standards lay down technical and procedural requirements related to obtaining and retaining a class certificate.
2.1.5 Where other standards and external criteria are used, the exact terms of reference and documents to be issued shall be agreed at the beginning of the project and formally defined in the contract. The use of other standards does not allow for a reduction of the quality management requirements as described in the safety philosophy of DNVGL-OS-E402.
2.1.6 DNV GL reserves the right to call for additional requirements to cover issues essential to the certification and classification process if not covered by the standards in question.
2.1.7 It is normally not acceptable to mix standards due to the possible differences in safety philosophies.
2.2 Statutory certification
2.2.1 The Society undertakes statutory certification on behalf of flag administrations when and to the extent the Society has been authorised to do so by the individual flag administration, in accordance with requirements given in the IMO code of safety for diving systems adopted by IMO resolution A.831(19). A corresponding diving system safety certificate may be issued upon proof of compliance when and to the extent the Society has been authorised to do so by the individual Flag Administration. Guidance note: If not authorized or if the flag has not adapted the IMO code, DNV GL may issue a statement of compliance.
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DNV GL AS 3 Classification scope and notations
3.1 Scope
3.1.1 The following parts and systems are covered by classification of a diving system: a) chambers Section 2 b) bell(s) c) permanent gas storage containers d) other pressure vessels e) life support systems f) divers heating systems g) electrical systems and installations
h) fire protection, detection and extinction Chapter 1 i) launch and recovery system(s) j) main umbilical(s) k) pipes, valves and fittings l) booster pumps and compressors m) helium reclaim plant (if installed) n) gas analysers o) gas mixing units p) gas absorbers q) breathing systems r) depth gauges s) sanitary system t) communication system. Guidance note: As lifesaving appliances are covered by statutory regulations, there may be overriding requirements for hyperbaric evacuation systems (HES). Consequently, it is important to inform DNV GL at an early stage what flag state is intended for the vessel and what geographical areas of operation the diving system should be approved for.
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3.1.2 The classification of the diving system will cover assembly of the components into a system and include the following: a) launching and recovery system for bell b) the arrangement of the diving system assembly c) the complete diving system assembly with respect to safety.
3.2 Class notations
3.2.1 A diving system class notation Diving system(Surface) or Diving system(SAT) for surface and saturation diving systems respectively, will be issued in the diving system’s classification certificate as a formal statement confirming that the diving system has been assembled, tested and commissioned in accordance with specified requirements.
3.2.2 The operational restrictions as listed in Table 1 apply.
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DNV GL AS Table 1 Class notations
Design and certification Class Restrictions Provisions requirements
dmax< 60 msw
Top< 8 hours open bell or basket
deployment allowed Section 2 Diving system(Surface) Ch.2 Sec.1 maximum operation time for chamber during treatment No HES required Ttr as approved
as stated in the requirements and assumptions in the closed bell Diving system(SAT) Ch.2 Sec.2 certificate, appendix to Dedicated HES required classification certificate and Chapter 1 data sheet (20.201a)
msw = metres sea water.
dmax = maximum operating depth.
Guidance note: The major differences between Diving system(Surface) and Diving system(SAT) are requirements for the:
a) physical size of the chambers b) life support system c) control stand d) communication system e) capacity of emergency power supply.
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3.2.3 Requirements which do not specifically refer to Diving system(Surface) or Diving system(SAT), or which are called minimum requirements in these rules and the referred standards, apply to all systems.
4 Assignment of class
4.1 Assignment of class - new systems
4.1.1 General A request for classification of a new diving system shall be submitted in writing by the customer. The Society reserves the right to decline a request for classification. Assignment of class shall follow the requirements given in DNVGL-RU-OU-0101 Ch.1 Sec.4. The scope of attendance shall be agreed between the manufacturer and the Society before manufacturing commences.
4.1.2 Upon class request, the Society's surveyor will inspect the manufacture and assembly of the diving system and attend the necessary tests.
4.1.3 The degree of technical innovation in the diving system shall be considered.
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DNV GL AS Guidance note: Risks to the diving operation are likely to be greater for a diving system with a high degree of technical innovation than with a diving system designed, manufactured and installed to well-known criteria in well-known vessels. Similarly, the degree of risk to the diving system should be considered where contractors are inexperienced or the work schedule is tight. Factors to be considered include:
a) degree of difficulty in achieving technical requirements b) knowledge of similar diving systems Section 2 c) knowledge of contractors’ general system experience d) knowledge of contractors’ experience in similar work.
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4.1.4 Plan approval Documents required in each section of DNVGL-OS-E402 shall be submitted for review and or approval by DNV GL. Chapter 1
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DNV GL AS Guidance note: Plan approval includes:
a) reviewing specifications for design b) reviewing design reports and drawings c) performing independent parallel calculations for certain systems and components d) reviewing specifications for manufacture and operation, resulting from design.
Definition of scope of work for plan approval of design will follow Table 2. Section 2
Table 2 Scope of work for plan approval of design
Plan approval activity
Review of the design process by
a) review of design quality management documentation Chapter 1 b) audit of design quality management system
Review of specifications for design by
c) review of the design basis with emphasis on the typical location on and interface with the support vessel. Evaluation of the design criteria, specifically or in general depending on the installation
Review of design reports and drawings by
d) review of the main documentation to ensure that the main conditions have been accounted for in design, that the governing conditions are identified, and that the chosen design philosophies are in accordance with specified codes and standards
e) evaluation of the main methods used and spot checks of the input data and the calculation results
f) detail review of main design reports
Performing independent parallel calculations by
g) simplified independent analysis and calculation(s) performed by spot checks
h) advanced independent analysis and calculation(s) performed by spot checks
Review of specifications for manufacture and operation by
i) spot check of critical aspects
j) review of main specifications
k) review of underlying specifications
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4.2 Survey during construction
4.2.1 General Where DNVGL-OS-E402 refers to certification, survey, acceptance, agreement or qualification this shall be done by DNV GL. Inspections and test executed as part of the construction surveys shall be included in the inspection and test plan (ITP) in accordance with DNVGL-OS-E402 Ch.2 Sec.1 [3.2].
4.2.2 Survey during manufacture, assembly and installation Survey during manufacture is either carried out by means of full time attendance, audits, inspection or spot checks of the work, as appropriate, in sufficient detail to verify that the specified requirements of the diving system are complied with.
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DNV GL AS 4.2.3 Verification of these activities relates not only to the contractor’s work but also to the monitoring of work carried out by others.
4.2.4 Verification shall consist of one, or more, of the following: a) reviewing the manufacture process b) reviewing manufacture procedures Section 2 c) reviewing qualification process d) surveillance during manufacture activities e) reviewing final documentation.
4.2.5 Definition of scope of work for manufacturing shall follow Table 3.
Table 3 Scope of work for attendance during manufacturing and fabrication of components Chapter 1
Survey activity
Review of the manufacturing and fabrication process
a) review of manufacturing management systems
b) audit of the quality management system
Review of manufacturing and fabrication procedures
c) review manufacturing, fabrication, method and inspection procedures for confirmation of compliance with the manufacturing specification
Review of qualification process
d) review the manufacturing procedure specification, (MPS), manufacturing procedure qualification test (MPQT), if applicable
e) review MPQT, if applicable, or first day production
Surveillance during manufacturing and fabrication activities
f) follow up during testing, to ensure, based on spot checks, that the delivered products or processes are in accordance with the manufacturing specification
Review of final documentation
4.2.6 Definition of scope of work for installation shall follow Table 4.
Table 4 Scope of work for attendance during installation
Verification activity
Review of the installation process
a) review of installation management systems
b) audit of the quality management system
Review of installation procedures
c) spot check of installation manual (IM)
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DNV GL AS Verification activity
d) for critical operations (identified from the systematic review) review the IM
Review of qualification process
e) for critical operations, review the qualification of the IM
f) follow up during tests, if applicable, or at start-up Section 2
Surveillance during installation activities
g) follow up during sub-system installations
h)follow up during trials and associated visit- based attendance during testing
Review of final documentation Chapter 1 4.2.7 Testing and commissioning After completed installation, the diving system shall be tested in compliance with an approved test program in presence of the surveyor according to Table 5. The required tests are stated in DNVGL-OS-E402.
Table 5 Scope of work for attendance during final testing for operation, including as-built survey and project completion
Verification activity
Review of procedures
a) review of the procedures for system tests to ensure that the test procedure will test the diving system in accordance with the design requirements
Surveillance during testing and completion activities
b) attendance during pressure testing
c) full time attendance during pipe testing and audit based attendance during cleaning, and drying
d) follow up during as-built surveying and system testing
Review of final documentation
e) review of as-built documentation
4.2.8 For environmental control systems a copy of the approved test program completed with the final set points will be endorsed by the surveyor, and shall eventually be kept available on-board.
4.3 Assignment of class - existing systems
4.3.1 A request for class entry of an existing diving system shall be submitted in writing by the customer. The Society reserves the right to accept or decline an application for class entry. The assignment of class shall follow the requirements given in DNVGL-RU-OU-0101 Ch.1 Sec.4 [2].
4.3.2 When a diving system, or part of a diving system, has been certified by another recognised classification society, evidence of previous design approval will be required. Such evidence shall include drawings of the arrangement and details bearing the approval stamp, or specifically covered by an approval
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DNV GL AS letter. In addition, for components requiring certification, the corresponding certificates shall be available along with maintenance records.
4.3.3 After review of the evidence and examination and testing in accordance with relevant parts of DNVGL- OS-E402, the system or components may be registered under the class notation with DNV GL.
4.4 Classification certificate Section 2
4.4.1 When all the applicable classification requirements have been met the Society will issue a class certificate as proof of assignment of class.
4.4.2 A data sheet for diving systems will be issued to support the class notation by giving a description of the diving system, operational limitations and conditions of use for which the diving system is intended, codes and standards with which the diving system has been found to comply, its item number (when relevant) and referencing certificates and reports of components in the diving system. Chapter 1
4.4.3 When a diving system has been assigned class, its main particulars and details of the class assigned will be entered in the Society's register according to requirements given in DNVGL-RU-OU-0101 Ch.1 Sec.4 [4].
5 Retention of class
5.1 Conditions of retention of class
5.1.1 Classification is based on the assumption that: a) the diving system is properly maintained and operated by competent personnel b) that a pre-check procedure is followed to ensure that all systems and components function properly before start of each operation c) that the current, wave and wind conditions are within the design limits for the various systems.
5.1.2 Diving systems in operation will retain class provided that: a) The diving system is operated within the specified limitations. b) Periodical surveys are carried out in accordance with Ch.3 based on an approved survey planning document (SPD) covering the diving system. c) The owner provides adequate documentation from inspection and maintenance activities. d) The owner maintains any installed systems for condition monitoring and carries out condition evaluations as applicable. e) Information about damage, repairs and modifications, which may affect the certification, is promptly reported to the Society. f) Conditions of class (CC) issued by the Society are acted upon within the specified time.
5.1.3 Diving systems that are temporarily out of service shall be subject to periodical inspections for retention of class. The inspection requirements will be agreed upon between the owner and the Society.
5.2 Damage and repairs For repair and replacement of significant components of the diving system, re-testing and/or certification shall be in accordance with these rules. See Ch.3 Sec.1 [4].
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DNV GL AS 5.3 Withdrawal of class
5.3.1 The class notation can be withdrawn if the owner fails to: a) comply with the operational procedures for the diving system accepted by the Society b) carry out the regular in-service inspection and maintenance programme according to the procedures
accepted by the Society Section 2 c) comply with any conditions of class issued by the Society.
5.3.2 Additionally, the class notation can be withdrawn if the diving system: a) is damaged, or is suspected of having been damaged, in a manner likely to impair its safety or integrity b) demonstrates signs of deterioration likely to impair its safety or integrity c) is subjected to any modifications or repairs, which can impair its safety or integrity
d) is considered demobilised or taken out of use. Chapter 1
5.3.3 If the situation leading to withdrawal of the class notation no longer exists, the notation may be reinstated. However, the diving system will be subject to special assessment or monitoring prior to and or following the reinstating of the class notation.
6 Certification of materials, components and systems
6.1 Introduction
6.1.1 The scope of classification requires that specified materials and components intended for the diving system are certified. The objective of this certification is to ensure that applied materials and components comply with the technical requirements. Certification normally includes both plan approval and survey during production and/or of the final product, (see DNVGL-RU-OU-0101 Ch.1 Sec.6).
6.1.2 Ch.2 defines the extent of the required certification. Guidance note: Certification should be planned in close co-operation with the owner and each of its contractors, to provide a scope of work that is tailor-made to the schedule of each production process or activity, i.e. to make the verification activities, surveillance and hold points, an integrated activity.
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6.2 Type approval Type approval is a procedure for approval of standard designs and/or routinely manufactured, identical components, systems or assemblies to be used in DNV GL classed diving systems. Type approval is detailed further in DNVGL-RU-OU-0101 Ch.1 Sec.6 [2.3].
7 Legal provisions Legal provisions are given in DNVGL-RU-OU-0101 App.A.
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DNV GL AS CHAPTER 2 DESIGN, CONSTRUCTION AND CERTIFICATION PROVISIONS
SECTION 1 SURFACE DIVING SYSTEMS Section 1 1 Introduction This chapter provides the procedural and technical requirements as applicable for the classification of surface diving systems. Systems complying with these requirements will be assigned a class notation Diving system(Surface).
2 Technical requirements
The technical requirements of DNVGL-OS-E402 Ch.2 shall be applied. Chapter 2
3 Documentation requirements Documentation requirements are described in DNVGL-OS-E402 Ch.2 Sec.1 [2] and the component specific requirements are listed in DNVGL-OS-E402 Ch.2 Sec.2 to DNVGL-OS-E402 Ch.2 Sec.8.
4 Survey and testing requirements
4.1 General
4.1.1 The tests carried out shall follow the test descriptions of DNVGL-OS-E402 Ch.2 Sec.2 to DNVGL-OS- E402 Ch.2 Sec.8. The Society may increase the extent of tests when deemed necessary.
4.1.2 Testing shall be in compliance with approved programmes.
4.2 Survey and testing requirements during and after installation
4.2.1 The diving system shall be tested at sea trials on-board according to an approved programme.
4.2.2 During the sea trials the normal launch and recovery system shall be tested to the maximum depth. For surface diving systems employing a wet-bell the bell shall be checked for leakage at depth, including gas cylinders, piping and hoses.
4.2.3 Drills shall be held to assure adequate access for the divers, and the ability to transfer an injured diver, to the chamber, and to compress the chamber, within the time frame stipulated by the applied decompression tables.
5 Certification requirements
5.1 General
5.1.1 For general principles to certification see Ch.1 Sec.2 [6], for definitions of the compliance document types see DNVGL-CG-0550 Sec.3.
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DNV GL AS 5.2 Launch and recovery systems Launch and recovery systems shall normally be certified by a competent person as lifting appliances in accordance with the procedures applicable for the system and compliant with ILO convention no.152. Operational limitations shall be stated in the data sheet. For DNV GL classed diving systems a DNV GL product certificate type OLA101 will be issued for the LARS. Section 1 5.3 Component certification
Table 1 Certification requirements
Certificate Certification Item Issued by Additional description type standard
Pressure vessels Chapter 2 Manufacturers of PVHO AoM Society
Pressure vessels for human PC Society occupancy (PVHO)
Windows in PVHO PC Society ASME PVHO-1
Approval and testing of acrylic material in accordance with ASME PTR manufacturer PVHO-1
Window installation report PD manufacturer
Approved manufacturer from Manufacturers of gas cylinders AoM recognised body
See DNVGL-OS-E402 Ch.3 Sec.2 Pressure vessels, p . V < 1 PC manufacturer [5]
Certification according to DNVGL- Pressure vessels, p . V >= 1 PC Society RU-SHIP Pt.4 Ch.7
Seamless gas cylinders PC Society
Recognised Smaller seamless gas cylinders PC national body
Life support
Materials and components in See DNVGL-OS-E402 Ch.3 Sec.7 MD manufacturer oxygen systems [2.1.3]
Shock testing of hoses and valves PTR manufacturer for use in oxygen systems
Tested for noxious, toxic and Materials used in inner area PTR manufacturer flammable properties
BIBS masks PTR manufacturer Tested for work of breathing
Environmental control unit PC Society
Thermal balance testing PTR manufacturer
Gas control panels PC Society
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DNV GL AS Certificate Certification Item Issued by Additional description type standard
Internal carbon dioxide removal in PTR manufacturer chambers and bells
Chamber gas reclaim unit PC Society
Diver gas reclaim unit PC Society Section 1
Society/ DNVGL-RU-SHIP Pt.4 Ch.6 Sec.1 Piping for breathing gas PC manufacturer [2.1.5]
Flexible hose assemblies (with TAC Society couplings)
Bell umbilical PC Society
Valves, pressure regulators PC manufacturer Designed to recognised standard Chapter 2
PC + Safety valves, pressure relief PTR (set manufacturer valves and non-return valves pressure)
Flow fuse PTR manufacturer
Manifolds PC manufacturer
Compressors PC Society
Purification and filter systems PC Society
Electrical
Electrical switchboards See DNVGL-OS-D201
Lights PC manufacturer For hyperbaric use
See DNVGL-OS-E402 Ch.2 Sec.4 Electrical penetrators for pressure PC Society [1.6] or DNVGL-OS-E402 Ch.3 vessels Sec.4 [3.5.2]
Society/ See DNVGL-RU-SHIP Pt.4 Ch.8 Electrical motors PC manufacturer Sec.1 [2.3]
For electrical equipment in inner Pressure resistant enclosures PTR manufacturer area or on the bell
Society/ Cables TAC + PC manufacturer
For emergency circuits including fire resistant cables (IEC 60331) Society/ Fire proof cables TAC + PC or flame retardant for not critical manufacturer cabling
Fire
Fire detector for inner area TAC Society
Fire alarm system covering inner PC Society area
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DNV GL AS Certificate Certification Item Issued by Additional description type standard
Fixed fire fighting system in inner PC Society area
LARS
Winches and power packs PC Society Section 1
Stops and brakes PC Society If delivered separately
See DNVGL-ST-0378 wire ropes to Society/ be delivered with DNV GL product Wire ropes PC + PTR manufacturer certificate type CG4 or ILO FORM 4 certificate
PTR or Blocks and shackles manufacturer Chapter 2 CG3
Launch and recovery system PC Society certified as lifting appliance (OLA201)
Control, monitoring and safety systems
For automated and semi Saturation control system PC Society automated systems
Shutdown system on gas PC Society Replacing flow fuse circulation lines
Components in controls systems PC Society See DNVGL-OS-D202
LARS control and monitoring PC Society
Hot water system for divers PC Society Inspection category 3
Environmental control system PC Society
Temperature indicator PC manufacturer
Pressure indicators and gas PC manufacturer Accuracy analysers
Guidance note: PC: product certificate, PTR: product test report, AoM: approval of manufacturer, TAC: type approval certificate, see DNVGL- CG-0550 Sec.3
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DNV GL AS SECTION 2 SATURATION DIVING SYSTEMS
1 Introduction This section provides the procedural and technical requirements as applicable for the classification of saturation diving systems. Systems complying with these requirements will be assigned a class notation
Diving system(SAT) . Section 2
2 Technical requirements The technical requirements of DNVGL-OS-E402 Ch.3 shall be applied.
3 Documentation requirements For general principles to submitting documentation, see DNVGL-CG-0550 Sec.3. Chapter 2 Documentation as submitted for classification shall follow the component specific items as listed in DNVGL- OS-E402 Ch.3 Sec.2 to DNVGL-OS-E402 Ch.3 Sec.8.
4 Survey and testing requirements
4.1 General
4.1.1 The tests carried out shall follow the test descriptions of DNVGL-OS-E402 Ch.3 Sec.2 to DNVGL-OS- E402 Ch.3 Sec.8.
4.1.2 Testing shall be in compliance with approved programmes.
4.2 Survey and testing requirements during and after installation
4.2.1 The diving system shall be tested at sea trials onboard according to an approved programme.
4.2.2 During the sea trials the normal launch and recovery system shall be tested to the maximum depth. For surface diving systems employing a wet-bell the bell shall be checked for leakage at depth, including gas cylinders, piping and hoses.
4.2.3 Drills shall be held to assure adequate access for the divers and the ability to transfer an injured diver to the chamber, and to compress the chamber, within the time frame stipulated by the applied decompression tables.
5 Certification requirements
5.1 General
5.1.1 For general principles to certification, see Ch.1 Sec.2 [6], for definitions of the compliance document types, see DNVGL-CG-0550 Sec.3.
5.2 Launch and recovery systems Launch and recovery systems shall normally be certified by a competent person as lifting appliances in accordance with the procedures applicable for the system and compliant with ILO convention no.152.
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DNV GL AS Operational limitations shall be stated in the data sheet (see Ch.1 Sec.2 [4.4]), a DNV GL product certificate type OLA 201 will be issued for the LARS.
5.3 Component certification
Table 1 Certification requirements Section 2 Certificate Certification Item Issued by Additional description type standard
Pressure vessels
Manufacturers of PVHO AoM Society
Pressure vessels for human PC Society occupancy (PVHO) Chapter 2 Windows in PVHO PC Society ASME PVHO-1
Approval and testing of acrylic material in accordance with ASME PTR manufacturer PVHO-1
Window installation report PD manufacturer
Approved manufacturer from Manufacturers of gas cylinders AoM recognised body
See DNVGL-OS-E402 Ch.3 Sec.2 Pressure vessels, p . V < 1 PC manufacturer [5]
Certification according to DNVGL- Pressure vessels, p . V > 1 PC Society RU-SHIP Pt.4 Ch.7
Seamless gas cylinders PC Society
Recognised Smaller seamless gas cylinders PC national body
Life support
Materials and components in See DNVGL-OS-E402 Ch.3 Sec.7 MD manufacturer oxygen systems [2.1.3]
Shock testing of hoses and valves PTR manufacturer for use in oxygen systems
Tested for noxious, toxic and Materials used in inner area PTR manufacturer flammable properties
BIBS masks PTR manufacturer Tested for work of breathing
Environmental control unit PC Society
Thermal balance testing PTR manufacturer
Gas control panels PC Society
Internal carbon dioxide removal in PTR manufacturer chambers and bells
Chamber gas reclaim unit PC Society
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DNV GL AS Certificate Certification Item Issued by Additional description type standard
Diver gas reclaim unit PC Society
Society/ DNVGL-RU-SHIP Pt.4 Ch.6 Sec.1 Piping for breathing gas PC manufacturer [2.1.5]
Flexible hose assemblies (with Section 2 TAC Society couplings)
Bell umbilical PC Society
Valves, pressure regulators PC manufacturer Designed to recognised standard
PC + Safety valves, pressure relief PTR (set manufacturer valves and non-return valves pressure) Chapter 2
Flow fuse PTR manufacturer
Manifolds PC manufacturer
Compressors PC Society
Purification and filter systems PC Society
Electrical
Electrical switchboards See DNVGL-OS-D201
Lights PC manufacturer For hyperbaric use
See DNVGL-OS-E402 Ch.2 Sec.4 Electrical penetrators for pressure PC Society [1.6] or DNVGL-OS-E402 Ch.3 vessels Sec.4 [3.5.2]
Society/ See DNVGL-RU-SHIP Pt.4 Ch.8 Electrical motors PC manufacturer Sec.1 [2.3]
For electrical equipment in inner Pressure resistant enclosures PTR manufacturer area or on the bell
Society/ Cables TAC + PC manufacturer
For emergency circuits including fire resistant cables (IEC 60331) Society/ Fire proof cables TAC + PC or flame retardant for not critical manufacturer cabling
Fire
Fire detector for inner area TAC Society
Fire alarm system covering inner PC Society area
Fixed fire fighting system in inner PC Society area
LARS
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DNV GL AS Certificate Certification Item Issued by Additional description type standard
Winches and power packs PC Society
Stops and brakes PC Society If delivered separately
See DNVGL-ST-0378, wire ropes to
Society/ be delivered with DNV GL product Section 2 Wire ropes PC + PTR manufacturer certificate type CG4 or ILO FORM 4 certificate
PTR or Blocks and shackles manufacturer CG3
Launch and recovery system PC Society certified as lifting appliance (OLA201) Chapter 2 Control, monitoring and safety systems
For automated and semi Saturation control system PC Society automated systems
Shutdown system on gas PC Society Replacing flow fuse circulation lines
Components in controls systems PC Society See DNVGL-OS-D202
LARS control and monitoring PC Society
Hot water system for divers PC Society Inspection category 3
Environmental control system PC Society
Temperature indicator PC manufacturer
Pressure indicators and gas PC manufacturer Accuracy analysers
Guidance note: PC: product certificate, PTR: product test report, AoM: approval of manufacturer, TAC: type approval certificate, see DNVGL- CG-0550 Sec.3
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DNV GL AS CHAPTER 3 CLASSIFICATION IN OPERATION
SECTION 1 PRINCIPLES FOR SURVEYS
1 Introduction Section 1
1.1 General This chapter lists requirements and criteria for the survey of diving systems. These shall be applied to the survey planning document as described Sec.2 [1].
1.2 Other codes
This chapter is intended to comply with the inspection requirements given in: Chapter 3 — IMO code of safety for diving systems, 1995 resolution A.831(19). — IMO guidelines and specifications for hyperbaric evacuation systems, 1991 resolution A.692(17).
2 Survey execution
2.1 General
2.1.1 Surveys may be carried out with the vessel on location or in port as long as the diving system is not pressurised. Pressure vessels requiring internal inspection should be depressurised, opened up, cleaned and made ready for survey.
2.1.2 Internal inspections of gas storage bottles should be carried out in accordance with an approved procedure by an approved service supplier. Consult the register of approved service suppliers.
2.1.3 The diving system status as accessible through My services on https://www.veracity.com and lists the planned surveys.
2.2 Introduction
2.2.1 This section is applicable for units with the notation DSV(SAT), DSV(SURF), Diving system(SAT), Diving system(SURF), DSV(III) or DSV(I).
2.2.2 Due to the physical extent, and large number of safety critical variations within diving systems, all diving systems shall be surveyed based on an approved survey arrangement utilising a planned maintenance system (PMS). The system will be given the survey code, diving system planned maintenance system (DSPMS). The approach in this chapter is based on the requirements for PMS systematics in DNVGL-RU-OU-0300 Ch.2 Sec.2, and is the interpretation of how to apply these requirements in a diving context. The below survey arrangements are adoptions of similar arrangements listed in DNVGL-RU-OU-0300 Ch.2 Sec.2. They are however not viewed as directly applicable to diving systems at this time, primarily due to limited historic data. Use on a case-by-case basis may be considered, provided the supporting data and documentation is available and suitable: — equipment planned maintenance – reliability centred maintenance (DSPMS RCM), see DNVGL-RU- OU-0300 Ch.2 Sec.3 [4] — equipment condition based maintenance (DSCBMSA), see DNVGL-RU-OU-0300 Ch.2 Sec.3 [5].
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DNV GL AS This does not preclude the use of data from sensors to extend service intervals where the measurements are defined in other proven standards (e.g. pressure vessel cycling). Such data may be handled within the DSPMS arrangement.
2.2.3 Structure of documentation The survey planning document (SPD) maps the system and defines the scope that the PMS system will cover. This includes periodicity of inspections and test procedures that document the items in the PMS. Section 1 The computerised maintenance management system (CMMS) is the software that is used to implement the diving system planned maintenance (DSPMS). The diving system planned maintenance (DSPMS) covers the inspection points that are carried out.
3 Diving system planned maintenance system
3.1 General Chapter 3
3.1.1 Diving system planned maintenance system (DSPMS) is a survey arrangement that covers the items listed in Sec.2 [2] and the survey planning document.
3.1.2 The DSPMS is based on approval of the company management and the implemented planned maintenance system on board.
3.1.3 All damage/break-downs on class related items shall be reported to the Society. Guidance note: See DNVGL-RU-OU-0300 Ch.1 Sec.3 [1.2.2] for additional guidance on damage/break-downs.
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3.2 Approval process
3.2.1 The approval process consists of the following steps: — maintenance management approval — approval of survey planning document — approval of CMMS system — approval of diving system planned maintenance system — initial audit on board — periodical audits — approval of updates as required.
3.2.2 Maintenance management approval A maintenance management approval is performed to ensure that the owner of the system can document satisfactory maintenance supportability in the organisation. The approval shall include a documentation review based on the following: a) maintenance strategy supporting a DSPMS survey arrangement b) management with necessary resources required to sufficiently support a DSPMS survey arrangement c) governing documentation (procedures) and working processes related to the DSPMS for the unit(s) d) quality management system supporting: — competence level on involved maintenance personnel — supervision and verification of work
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DNV GL AS — continuous improvement process.
3.2.2.1 Maintenance resources It is the responsibility of the owner to organise, manage and develop the maintenance resources (personnel, materials and equipment) on board to provide sufficient maintenance supportability at all times. The owner shall, based on the diving system and systems as defined in Sec.2 [2] and on board the unit, ensure sufficient technical competence related to required maintenance level (maintenance task categorisation by complexity) according to type and function of the equipment. Section 1 Guidance note: It is recommended to categorize the equipment on board and associate it to a predefined maintenance level. The maintenance level should reflect the increasing complexity of the tasks. E.g. maintenance levels as defined in EN 13306:
— Level 1: Simple actions/routine — Level 2: Basic actions/preventive/corrective — Level 3: Complex actions (overhaul) with detailed procedures
— Level 4: Actions (overhaul) requiring detailed know how (specialized personnel) Chapter 3 — Level 5: Actions (overhaul) requiring knowledge held by the OEM.
Maintenance personnel should be qualified according to the defined maintenance levels.
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3.2.2.2 Responsible person The owner shall dedicate a responsible person (supervisor) on board the unit to ensure the integrity of the arrangement. The responsible person shall ensure appropriate execution according to the survey arrangement and be responsible for the professional standard of the resources on board to provide sufficient maintenance supportability at all times. The responsible person shall be a qualified professional with documented qualifications and skills related to technical operations and maintenance of applicable diving systems and equipment. Guidance note: It is recommended to apply EN 15628 – Qualification of Maintenance personnel or equivalent when establishing requirements and documenting qualifications for the position. This standard gives guidance on required knowledge, minimum skills and competencies applicable for maintenance personnel. The responsible person should as a minimum comply with the requirements of maintenance supervisor and maintenance engineer defined by EN 15628. Alternatively a solution involving maintenance management onshore as part of the arrangement can be considered on a case-by-case basis.
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3.2.2.3 Verification For all essential or emergency equipment the owner of the unit shall ensure that independent verification of work performed on the equipment is carried out. Verification shall be based on the maintenance task complexity and performed by the Society, or by owner's qualified personnel. Verification shall not be done by the person(s) performing the maintenance task(s). Verification of high level complexity (overhaul) should be performed by the Society. Verification shall be registered and documented in CMMS. Any repair or modification performed on essential equipment shall be approved and verified by the Society, see DNVGL-OS-E402 Ch.3 Sec.1 [2.3]. Guidance note: Verification may be performed by responsible person, see DNVGL-RU-OU-0300 Ch.2 Sec.3 [3.2.2.2], or other qualified personnel part of the arrangement.
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DNV GL AS 3.2.3 Approval of computerised maintenance management system (CMMS) Computerised maintenance management system (CMMS) is subject to approval by the Society, either a type approved system or non-type approved system (case-by-case approval). See DNVGL-RU-SHIP Pt.7 Ch.1 Sec.7 [3.2] for further details. The CMMS shall have functionalities that make it able to:
— Record and separate between different types of maintenance such as: Section 1 1) scheduled maintenance (preventive maintenance/deferred corrective maintenance) 2) un-scheduled maintenance (immediate corrective maintenance). — Produce maintenance history reports on maintenance carried out for a specific time period on machinery class items. — Register revisions of maintenance tasks (traceability). — Provide verification of class related maintenance tasks/jobs (quality of work and correct/sufficient level of reporting). Chapter 3 — Provide access control to assure that changes to the system cannot be made by unauthorised personnel and any input will be traceable to the individual user. — Back-up data and make it possible to restore all data for minimum five (5) years.
3.2.4 Diving system planned maintenance programme approval The following requirements apply for the approval: a) The maintenance programme shall include the equipment and systems as described within the survey planning document and the general items listed in Sec.2 [2]. All these components shall be identified as class items in the system. b) Maintenance tasks and intervals shall be based on original equipment maker's (OEM's) recommendations and the standards that govern the equipment/system. c) OEM maintenance recommendations should be applied as specified by the OEM, but tasks and interval should normally be confirmed appropriate for the specific environment and operations of the applicable equipment. d) Systems and equipment shall be evaluated according to maintenance level, type and function. Maintenance personnel shall be qualified for the applicable maintenance task (based on maintenance level, type and function). e) All maintenance tasks shall have: — detailed task description to the level of detail necessary for a skilled maintenance person — maintenance task interval — task preparation note describing any preparation necessary — maintenance level indicating qualification level of personnel to perform the task — verification level indicating verification by owner or the Society — required materials (consumables, spare parts and special tools) — applicable documentation (maintenance procedures and service manuals and drawings) readily available on board — checks and measurements to be made — descriptions and maintenance history in English. Guidance note: It is recommended to apply EN 13306 – Maintenance terminology, or equivalent in development of a maintenance system.
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DNV GL AS 3.2.5 Initial audit An initial audit shall be carried out on board the unit in order to verify that the system has been implemented in accordance with the approved documentation and that the system is used as intended. It is recommended that the system has been operated for at least six (6) months before the initial survey is carried out. During the initial audit, it shall be verified that: — There are sufficient resources available on board the unit to ensure the integrity of the arrangement. Section 1 Personnel engaged in performing maintenance tasks on the equipment have the correct competence based on maintenance level, type and function of the equipment. — Responsible person on board has the sufficient knowledge and access to applicable procedures and documentation to ensure correct operations according to the arrangement. — The responsible person is familiar with the CMMS and is able to demonstrate the different functionalities in the system to the attending surveyor. — The general condition and maintenance of the diving system and systems is good.
Provided the initial audit is carried out with a satisfactory result, the survey arrangement DSPMS shall be Chapter 3 granted and a survey report will be issued stating system name and conditions for the survey arrangement for the specific unit. Guidance note: Prior to the initial audit on board, the maintenance management approval, (see DNVGL-RU-OU-0300 Ch.2 Sec.3 [3.2.2]) and approval of the diving system planned maintenance programme, (see DNVGL-RU-OU-0300 Ch.2 Sec.3 [3.2.3]) may be carried out in the owners office. In such cases all applicable documentation and the on board database shall be available in the owners office.
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4 Out of service Diving systems that are temporarily out of service shall be given the status laid up and subject to periodical inspections. The inspection requirements will be agreed upon between the owner and DNV GL on a case-by- case basis.
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DNV GL AS SECTION 2 PERIODICAL SURVEYS
1 Survey planning document The survey planning documents main purpose is to describe the system scope and allow the approval of the diving system planned maintenance system (DSPMS).
The owner shall document their routines for inspection and maintenance of the dive equipment. The Section 2 documentation may be done in a PMS or other documented inspections. It shall include procedures for any necessary testing that is carried out both as specified in the DSPMS and for the tests outlined in this section. Where regular checklists are utilised to confirm functionality of the system, e.g. bell checklist, these checklists shall be included in the documentation for approval. Where particular qualifications are required to carry out elements in the DSPMS, the means to achieve them
shall be described, e.g performing OVI and MVI as per ASME PVHO-2. Chapter 3 Any testing shall comply to the test requirements in the relevant sections of DNVGL-OS-E402 and OEM suppliers instructions. Relevant OEM maintenance documentation shall be included as an appendix to the survey planning document. The checklists, test procedures and OEM information should take the form of appendices to the survey planning document. For mobile systems the survey planning document shall detail the inspection and test requirements at mobilisation/demobilisation. Where a system can be mobilised in different configurations, details of all applicable configurations shall be documented. The following items shall as a minimum be covered: — A description/breakdown of the diving system, (e.g. describing the different gas lines) and how these subsystems are organised and followed up within the PMS. — Follow up from the systematic risk assessment and ensuring the appendices described in DNVGL-OS-E402 Ch.3 Sec.1 [2.2] and DNVGL-OS-E402 Ch.2 Sec.1 [4.7] are covered. — A test programme to confirm continued operation as per the systemic risk assessment test program carried out at newbuilding. All items should be tested at least once during a five (5) year period, see DNVGL-OS-E402 Ch.3 Sec.1 [2.2.3]. — Details of procedures that are used to confirm elements in the DSPMS and a schedule to audit these procedures during annual surveys over the five (5) years period shall be provided. — Where OEM maintenance instructions are used for planning follow up of equipment, copies of these instructions shall be provided for information. Particular attention shall be given to developing a targeted inspection regime for the LARS. — A register of essential gauges and clocks shall be maintained by the owner. Inspection and calibration of the gauges and indicators critical for the life support system shall be carried out by a competent person and the schedule shall be described. Oxygen gauges shall be controlled in order to ensure they are of the correct type. — A register of permanently installed combustible components within the inner area shall be maintained. This shall include items such as paints, mattresses, lubricants and other soft furnishings that pose a risk of contamination. — A register of permanently installed safety valves in the dive system should be kept detailing the serial number of the valves and their set points. Valves should be labelled with lifting and seating set points along with the date of their last test (valves should be tested individually on a test stand). — Testing of all emergency systems. — Testing of bell buoyancy. — A register of pressure vessels shall be maintained.
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DNV GL AS — A register of equipment controlled by PLCs including those controlling systems locally as well as at control stands. The register shall track software versions and give reference to function testing subsequent to software modifications. — Hyperbaric evacuation system tests and drills. The survey planning document should also include sign off sheets/reports from the DSPMS for reporting purposes after the survey.
Where the diving system has not been in use since last survey, the applicability of in-service monitoring shall Section 2 be reviewed with particular focus on the use of operational check lists. These checklists shall be completed during the survey. This shall be recorded as additional scope.
2 Planned maintenance system - PMS Items that as a minimum shall be included in the DSPMS: — Ensure that pressure vessels have been examined and tested within their respective test dates.
— Ensure that pressure vessels with a limited design life (e.g filter housings) that are not inspected/tested to Chapter 3 the Society's rules are replaced within their respective dates. — Ensure that windows are replaced within their respective dates and required ASME reports completed. — Servicing of fire extinguishers/systems. — Ensure gas quality, including bacterial growth, segregation and gas management. — Document gas quality testing where required after reclaim and upon delivery of gas to the system. — Flexible hoses are managed and inspected. — Monitor gas tightness. — Means to control temporary pressurised equipment such as gas quads are in place. This includes gas composition, pressure vessels, associated hoses and regulators/safety valves. — Pumps and compressors are followed up as per manufacturer's instructions. — Calibration of essential gauges and clocks should be carried out on a six (6) monthly basis by a competent person and verified by marking on the gauge and updating of lists. — Function testing of control stands is carried out on a regular basis. operational checklists may be used in conjunction with the DSPMS. — Piping inspections are done on a regular basis. — Maintenance viewport inspection programme. — Wires used in the LARS (including clump we, should be cut and re-terminated at the bell end minimum every 12 months. The minimum length to be removed shall be from the bell to five (5) metres beyond the sheave nearest the bell, as it becomes fully submerged. The wire sample shall be tested, and the breaking load shall not be less than eight (8) times the SWL. This applies also for the clump weight and cursor wires. — For DNVGL classified systems, the re-socketing of wires shall be performed according to wire rope manufacturer's procedure and EN 13411-4 as per DNVGL-ST-0378 [3.10.1]. Only companies which have been approved by national accredited certification bodies may carry out the socketing. Load testing is not necessary if this is followed. Items to control: — Socket shall be fitted in accordance with wire rope manufacturer's recommendations. — If socket is re-used, there shall be no damages to the socket. — If new, the socket shall be delivered with manufacturer's certificate. — The epoxy resin shall be within date. It is of utmost importance that the wires are clean and de-greased, and that the wire that shall be inserted in the socket is well 'brushed out' before the resin is poured. — Details of wire maintenance for the LARS including control of wire certificates and that non rotating wires are used when required.
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DNV GL AS — List of spring and shear pins that have specified properties e.g. to prevent accidental use of umbilical cutter. — Alarms throughout the system. — Insulation testing of electrical systems. — Regular check of flow fuse cleanliness. Section 2 3 Annual survey The data sheet for diving system needs to be updated based on any changes since the last survey and altered if necessary. It is the owner's responsibility to ensure that the data sheet is updated prior to the periodical surveys. The class surveyor will endorse the data sheet along with the owner to confirm the scope of the certification. The management of change system employed by the owner shall be reviewed as necessary. The owner shall also ensure that any conditions of class relating to DYNPOS(AUTR)/POSMOOR(V) are addressed as these may have influence on the dive system status. Chapter 3
3.1 Annual audit of diving system planned maintenance system - DSPMS
3.1.1 To maintain the validity of the survey arrangement DSPMS, an annual audit of the implemented planned maintenance system is required. The purpose of this audit is to review and evaluate the previous period's maintenance activities and to ensure that the arrangement is working as intended.
3.1.2 During the annual audit records showing the following shall be available: a) All maintenance on class related items are carried out according to the maintenance programme. b) Responsible person on board the unit is familiar with the CMMS and is able to demonstrate the different functionalities in the system to the attending surveyor. c) Maintenance records (reporting). d) Documented assessment of overdue/postponed (deferred) maintenance tasks. e) Documentation of changes to the system, (maintenance intervals and job descriptions made by OEM). f) Certificates for essential equipment, see DNVGL-OS-E402 Ch.3 Sec.1 [4], available on board. g) General condition and maintenance of the diving system to be evaluated (rated). h) That the unit has a robust and operational continuous improvement function. Continuous improvement should utilise input from safety reports, feedback from maintenance personnel and information given by the OEM. Furthermore, the results of the improvement actions should be evaluated by the owner in order to ensure that real improvements are achieved. i) Changes to the OEM maintenance recommendations may be accepted when documented operational experience can justify the change and be supported by the OEM. Changes shall be traceable and presented to the attending surveyor at the next annual survey for acceptance. Documented experience will typically be service letters (bulletins) from the OEM, maintenance reports, wear measurements and maintenance history.
3.1.3 The surveyor may, if found necessary, require a re-audit including opening or testing of items reported by the responsible person on board.
3.1.4 Verification For maintenance tasks performed on essential equipment, requiring verification by the Society, the attending surveyor shall be contacted to agree on his/her involvement. The verification may be performed during the annual audit, see DNVGL-RU-OU-0300 Ch.2 Sec.3 [3.3.1] or during an occasional survey requested by the owner. Verification shall be registered and documented in CMMS.
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DNV GL AS 3.1.5 Damages Damage to diving system and systems covered by classification shall always be reported to the Society and into the CMMS as a corrective (unscheduled) maintenance task.
3.2 Visual Inspection
The following areas should be prepared for visual inspection and ensured in order prior to survey. Section 2
3.2.1 General (systemwide) The system should be clean. Permanent marking of equipment shall be maintained. Pipes should be marked with gas type and direction and panels should be clear and easily read. Oxygen lines are fitted with needle type valves. Hazard warning signs are provided prior to entering a storage area. Chapter 3 3.2.1.1 Viewports for PVHOs Inspection of windows are based upon ASME PVHO-1 and ASME PVHO-2. The latest requirements from these standards apply. Windows may be older than ten (10) years (as marked) provided they were stored in accordance with the requirements given in the standard prior to installation. The items listed below is important to document this. Windows should be examined for the following: a) Windows shall have a protective shield internally and externally, a 6 mm or thicker clear acrylic is suitable. b) Windows should be clear, without discolouring (e.g. yellowing due to acid formation), crazing, cracks or scratches. c) Maximum allowable depth of scratches on low pressure side: 0.3 mm and on high pressure side: 0.8 mm. d) Seal material shows no sign of creep, extrusion, cracking. e) The coated surface of the seat is undamaged. f) The operational inspector (OI) and maintenance inspector (MI) are in place as per survey planning document. g) A valid maintenance inspection has been completed with associated PVHO-2 VP-1 form within the last two (2) years or if coming out of lay-up. When windows are replaced the following items shall be available: a) PVHO-1 forms VP-1 to VP-5 shall be completed along with the approved drawing. b) An installation report documenting seating surface finish, measured tolerances, lubricants used as well as a PVHO-2 VP-1 shall be available from the MI. c) A leak test shall be carried out after installation. Guidance note: Window marking: XX(pressure)-XX(Temp in brkts for celsius)-PVHO-XX(fabricator initials)-XX(serial numb)-XX(year of fabrication).
Repair -XX(Fabricator initials)-XX(Fabricator serial numb-XX(year repair performed).
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3.2.1.2 Pressure vessels, seamless Structural integrity and corrosion status of gas containers, including supports and connections to relief valves. That cylinders are colour coded and marked with the name and chemical symbol of the gases they contain in accordance with DNVGL-OS-E402 Ch.3 Sec.1 [10] .
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DNV GL AS Review inspection reports completed since last annual audit. Where the pressure vessels are not subject to certification and inspection, it shall be verified that they are replaced as per the interval specified in the PMS.
3.2.1.3 Pressure vessels, other Structural integrity and corrosion status. Guidance note:
Inspection criteria for pipe based filter housings is as per survey planning document. Section 2
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3.2.2 Chamber deck Portable fire extinguishers outside chambers should be located as per the fire control plan.
3.2.2.1 Saturation control
The system should be clean. Permanent marking of equipment shall be maintained. Pipes should be marked Chapter 3 with gas type and direction and panels should be clear and easily read. CCTV should provide clear sight of for the divers inside the chambers.
3.2.2.2 Deck decompression chambers (DDC, TUP) The following shall be in order prior to survey: a) Paintwork is clean, in good condition, and free from corrosion. Paint used for maintenance should be recorded and have certification, (FTP code Annex 1 Part 2 smoke and toxicity test and Part 5 low flame spread). b) Special attention to the chamber shell under the deck plates, this is to ensure that no accumulation of water or corrosion is evident. Ultrasonic thickness measurements should be carried out at the discretion of the surveyor. c) Internal electrical cabling (cable ties to be metallic). d) N/O and N/C valves (e.g. fire fighting, pressure relief) are labelled as such and where applicable secured in the correct position. e) Open ended exhaust pipe work should be fitted with anti-suction guards to protect fingers and avoid blockage. f) Open ended inlet pipe work should be fitted with a metallic diffuser. g) The penetrations should be clearly marked to show their function. h) Hollow penetrations are fitted with skin valves inside and outside to prevent loss of pressure. i) Attachments are in good condition. j) Spring loaded bilge valve closes freely. k) Soft furnishing e.g. curtains/mattresses are certified, (FTP code Annex 1 Part 2 smoke and toxicity test and Part 5 low flame spread). l) That doors that can be opened from both sides, can be secured open and have equalising valve where appropriate. Chamber doors should be numbered. m) Sealing surfaces, o-rings and hinges on the chambers. n) Condition and number of BIBS connections and masks for the designated number of occupants, plus one spare, in each chamber. o) That portable fire extinguishers in the chambers are approved for hyperbaric use. p) That identification plates are fitted. q) Insulation should be clean, substantially free of damage and free from signs of corrosion underneath. r) Chamber penetrations (particularly NPT) are sound and there are no signs of incomplete tightening such as excessive thread tape. s) Chamber foundation condition including sliding zones/mechanical stoppers. t) The toilet flush system and function test it with special attention to safe working under pressure. Verify that the safety locking mechanisms is still in operation. The locking mechanism is to ensure that it is
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DNV GL AS not possible to sit on the toilet and flush it at the same time. This is often done by means of a linkage between the seat cover and a ½ turn valve.
3.2.3 Dive control/launch and recovery system area
3.2.3.1 Dive control system The system should be clean. Permanent marking of equipment shall be maintained. Pipes should be marked with gas type and direction and panels should be clear and easily read. Section 2 CCTV provides clear sight of for the divers inside the bell. CCTV/windows provide clear sight of of the LARS system. Where an ROV is being used in conjunction with diving operations a monitor should be provided in dive control and dedicated hard wired communications installed between the diving supervisor and ROV supervisor/pilot. Means to compensate bell analysis depth delay shall be in place. Chapter 3
3.2.3.2 Diving bell The following shall be in order: a) Paintwork is clean, in good condition, and free from corrosion. Paint used for maintenance should be recorded and have certification, (FTP code Annex 1 Part 2 smoke and toxicity test and Part 5 low flame spread). b) Special attention to the bell bilge area, un-sleeved penetrations for oxygen and hot water. Penetrations should be withdrawn if necessary to examine threads if significant signs of corrosion. c) Internal electrical cabling (cable ties to be metallic). d) That the onboard gas pressure can be read from inside and outside the bell. e) Bell panel and hydraulic valves are clearly labelled and instructions for emergency functions are signboarded. f) N/O and N/C valves are labelled as such and where applicable secured in the correct position. g) Open ended exhaust pipe work should be fitted with anti suction guards to protect fingers and avoid blockage. h) Open ended inlet pipe work should be fitted with a metallic diffuser. i) The penetrations should be clearly marked to show their function. j) Hollow penetrations are fitted with skin valves inside and outside to prevent loss of pressure. k) Attachments are in good condition. l) Enclosed equipment has vents that are unblocked and in good condition. m) A harness and lift for recovering an unconscious diver is in place and in good working order. n) Means available of securing each diver in the bell during descent and ascent in order to minimise the possibility of injury. There should be one seat fitted with a restraining harness provided in the bell for the stand-by diver. o) Spring loaded valves for flooding and bilge drain close freely and are fitted with guards. The drainage hose should reach all areas of the bilge. No electrical equipment should be below the flooding point. p) Enclosed equipment vents are unblocked and in good condition. q) Sealing surfaces, o-rings and hinges on the bell. r) Condition and number of BIBS connections and masks for the designated number of occupants, plus one spare, in each chamber. s) That the bell door can be opened from outside. t) That identification plates are fitted. u) Insulation should be clean, substantially free of damage and free from signs of corrosion underneath. v) Chamber penetrations particularly NPT for excessive thread tape signs of incomplete tightening. w) Connections for on board gas charging are clean and in good condition.
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DNV GL AS x) The external emergency connections: ¾'' NPT (female) for hot water, and ½'' NPT (female) for breathing mixture are clean and in good condition. y) Sacrificial anodes and bladders for equalising oil filled boxes are in good condition. The battery housing on the bell has a relief valve. z) Means to prevent flooding of the umbilical is in place and the umbilical is secured without loading penetrations (e.g. Chinese finger). aa) The presence of a standard bell emergency communication tapping code. A copy of the AODC emergency tapping code should be placed on the bell external where a rescue diver can easily read it. Section 2 ab) The emergency CO2 scrubber has correct amount and type of scrubbing material for 24 hours emergency operation and the means by which divers in the bell can monitor O2 and CO2 levels independently of the surface. (Note Draeger tubes are not accurate at pressure. A timed switch over for CO2 scrubbing may be accepted in lieu of an analyser).
3.2.3.3 Launch and recovery system
a) Supporting steelwork for the launch and recovery system including bolts shall be in order, NDT may be Chapter 3 required if it is considered necessary b) The sheaves and guide rollers that are in contact with the moving wire should not show excessive surface wear and the line out indicator shall be operational, see DNVGL-OS-E402 Ch.2 Sec.6. c) The bell main lifting arrangements, steel work and load bearing components shall be in order. NDT may be performed at the surveyor's discretion. d) The umbilical shall be secured to the bell by means of a strength member or strain relief fitting so that no bell penetration connections are subjected to load. e) A means shall be available to indicate the amount of umbilical, bell and guide wire that has been paid out. This may take the form of 'line out' indicators or identical markings on both the wire and umbilical at ten (10) m (or equivalent) intervals. f) Bell transfer and mating flanges shall be in good condition and aligned with the TUP. g) Hydraulic power system records showing the last oil analysis date was/shall be available. h) The means/tools to support the procedure for tertiary recovery of the bell (lost bell situation) shall be in place and drills are documented in the PMS. i) The attachment point on the bell for connection of the main lift wire shall be in order. j) The condition of wires and terminations, i.e. bell wire, guide wires, cursor wires may be assessed according to ISO standard 4309, Crane - Wire ropes - for lifting appliances - Care and maintenance, inspection and discard. The minimum breaking load should not been reduced by 10% or more of its strength compared to new. The factor of safety between rope strength and SWL should not fall below 8:1.
3.2.4 Machinery deck (tank top)
3.2.4.1 Chamber reclaim system The gas bag/gas bag enclosure is to be in good condition and the relief valve/bursting disc lead to a suitable vent.
3.2.4.2 Compressor unit Breathing air and gas delivered by compressors shall be tested for signs of contamination. Where this is subcontracted to an accepted service supplier records shall be available. The compressors CO shut downs shall be in place. Filtration units shall be changed as per OEM instructions.
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DNV GL AS 3.2.5 Outside equipment
3.2.5.1 Oxygen storage Oxygen quads shall be located as per the fire control and safety plan. Where additional gas is stored outside of the areas approved for storage these shall be considered under the dangerous goods code.
3.2.5.2 Hyperbaric lifeboat and hyperbaric rescue chamber Section 2 The lifeboat supplies and markings shall be in order as well as the applicable parts for chambers.
3.3 Test requirements This paragraph describe tests that the owner is responsible for planning and executing. The extent of witnessing of these tests by the Society shall be agreed as part of the survey planning between owner and the Society. Chapter 3
3.3.1 Chamber deck
3.3.1.1 Environmental control system Environmental conditioning units (ECU's), should be run up and the controls function tested. Back-up heaters should be function tested in every chamber. Single ECU failure, single switchboard failure and emergency power should be simulated (including the behaviour of alarms, temperature sensors and if the system remains under automated control).
3.3.1.2 Saturation control Examine and test instrumentation alarms according to PMS/SPD including: a) high/low pressure alarm for chamber, if fitted b) temperature alarm for chamber, if fitted c) humidity alarm for chamber, if fitted d) gas analyser alarms e) audio visual alarm O2 injection f) general alarm/muting g) UPS alarms. Test the following: a) change over from main to secondary to emergency electrical supply b) auto change over gas supply to divers c) O2 injection d) hi/low O2 alarms for SAT control atmosphere as well as repeaters from other areas. Communication testing. primary, secondary and emergency communication should be function tested, including between sat control and: a) each compartment b) bridge c) dive control d) all locations required by the evacuation procedure e) other control stands that may effect saturation control. The test should include use of the emergency breathing apparatus, headsets and other back up systems as well as back up control stands when utilised in automated/remote control systems. Open loop communication systems (e.g. clear com) should be arranged so as to allow separate dive control and sat control loops.
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DNV GL AS 3.3.1.3 Deck decompression cambers - DDC, TUP Flow fuses/electronic shutdowns should be tested by simulating that piping is suddenly opened to the atmosphere. Pressure interlocks shall be tested on medical and equipment lock(s).
3.3.2 Dive control/launch and recovery system area Section 2
3.3.2.1 Bell weight Determine the working weight of the bell and record this in the report: — the bell weight: [kn] or [kg] — the previous weight: [kn] or [kg]. The current weight shall be considered against the previous results. Ensure that a calibrated load cell is being used. The data sheet shall be updated with the current bell weight. Chapter 3
3.3.2.2 Functional load test (dynamic) The line out metre shall be reset to the current wire length. This is particularly important when the line out metre is used to stop the winch at maximum depth. Perform a dynamic load test of the launch and recovery system. Test load factors are 1.25 x working weight of bell with independent brake test: a) The bell should be loaded with 150 kg per diver plus the weight of his equipment and tools, times the number of divers the bell is rated for. b) The function test should be demonstrated by raising and lowering the bell on primary and secondary means (main wire and guide wire). Normal and emergency electrical power should be tested. The bell should stop gently without excessive creep. c) The test should be done all the way from TUP and down to waterline. d) Brakes should be tested independently by locking off each brake and examining for creep on the counter balance valve and vice versa. Creep should not be excessive. e) The hydraulic power system should be observed during running and examined for unusually high vibration levels, oil leakage, pressure peaks and jerking during bell launch and recovery. Oil analysis should be taken as necessary. f) Ensure that winch-operating levers returns to a central neutral position upon being released by the operator and that the 'raise', 'lower' and 'neutral' position of the operating levers are clearly marked. g) Ensure that the automatic brakes come into operation whenever the operating lever returns to the neutral position, or when there is a loss of operating power to the winches. Verify also that the secondary brakes operate in case of failure of the primary brakes. h) The required load may be achieved by using water bags, if there is space. Solid weights may also be used, or the load may be increased by partially filling the bell with fresh water through the hot water hoses. If the internal equipment is shielded, water contamination should not be a problem. On completion of testing, the water may be drained using the bell bilge drain, while increasing the internal pressure. If no bilge drain is available, a hose should be connected to the bell main exhaust before the water filling commences. i) The alignment between the bell and the chamber trunk should be verified. The bell should be mated to the chamber trunk and the closing devices function tested. Ensure the locking mechanisms function and that it is not possible to move the launch and recovery system when the bell is mated to the chambers. j) Test that alarms and safety functions are in order. Perform a simulated power failure test of the launch and recovery system according to the procedure for emergency retrieval of the bell.
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DNV GL AS 3.3.2.3 Buoyant ascent In certain circumstances reliance on buoyant ascent as a means of diver rescue may be utilised and should be examined to meet the criteria listed below: a) Drop weights shall be capable of release from inside the bell and precautions to prevent accidental release in working order.
b) The ballast release system should work in two independent stages, so that one action cannot release the Section 2 ballast. See DNVGL-OS-E402 Ch.2 Sec.7. c) Allowances should be made for the bell tilting during deployment in which case the weights should be incapable of inadvertent release i.e. falling off, while remaining capable of deliberate release. d) If operation of the primary and secondary release mechanisms relies on a common structural component, then an independent means shall be provided to retain the ballast i.e. no single component failure should result in buoyant ascent of the bell. e) Test the following bell emergency release mechanisms on the bell:
— umbilical connection/umbilical cutters Chapter 3 — lifting wire connection — guide wire release (if applicable) — ballast weights — where hydraulic/pneumatic systems are used their design shall be such as to preclude accidental activation by means of hydrostatic pressure or leakage of helium into the system. The mechanisms should be tested from inside the bell. The umbilical cutters and lifting wire cutters (if applicable) may be tested on a spare piece of umbilical/wire. On completion of the tests, ensure that shear pins of an acceptable quality are refitted, as required. Examine the blades on the cutters after testing, to ensure they have not been damaged or badly notched. Ensure that the release is carried out with the ballast weight supported to avoid shock loading on the bell.
3.3.2.4 Buoyancy check When one of the emergency systems for recovery of the bell is by buoyant ascent of the bell, the value of the positive buoyancy should be evaluated. Buoyancy may be affected by ingress of water into voids and differing external equipment (change of battery pod, gas bottles, etc). This shall be assessed by the latest weight of the bell in [3.3.2.1]. Buoyancy may also be affected by degradation of bell insulation and buoyancy blocks both from aging exposure and physical damage. Based on the period defined in the survey planning document buoyancy shall be tested. Where buoyancy and insulation are in good condition visually, the test blocks may be used. Where weight has increased, buoyancy materials/insulation have been damaged or renewed, or new external equipment has been fitted, a full scale buoyancy check shall be performed as below. a) The drop weights shall be removed for the test and the bell loaded with 150 kg per diver, plus the weight of his equipment, times the number of divers that the bell is rated for. b) The minimum required positive buoyancy is 3% of the total displacement including the external appendages, such as external lights and onboard gas, etc. c) The trunk shall also be filled with water. This may be accomplished by using a hose fitted in the trunk and led some distance up the side of the bell. Water pressure will then displace the air in the trunk. d) A comparison should be made with the results of the previous buoyancy test to see if any differences have occurred. e) Examine for unauthorised modification to the buoyancy. f) Details of buoyancy and stability shall be entered in the equipment register.
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DNV GL AS 3.3.2.5 Dive control system The alarms should be function tested as applicable, according to the manufacturer's instructions and SPD. Test instrumentation alarms according to the SPD that should include the following: a) divers hot water temperature alarms b) divers hot water pressure alarms c) reclaim alarms compressor shut downs, active gas make up, gas analysis Section 2 d) gas bag alarm e) LARS/HPU alarms f) general alarm/muting g) bell battery charging alarm h) UPS alarms. Test the following: a) change over from main to secondary to emergency electrical supply. Chapter 3 b) auto change over gas supply to divers c) gas bag alarm d) traffic light system e) hi/low O2 alarms for dive control atmosphere f) bell battery charging alarm g) UPS alarms. Communication testing: primary, secondary and emergency communication should be function tested, including communication to: a) divers b) bridge c) SAT control d) all locations required by the evacuation procedure e) other control stands that may effect divers in the water e.g. ROV, crane. The test should include use of the breathing sets, headsets and other back up systems as well as back up control stands when utilised in automated/remote control systems. All voice communications with divers should be recorded. Open loop communication systems (e.g. clear com) should be arranged so as to allow separate dive control and sat control loops. Through water communications to be tested including the ability to record communications with the divers.
3.3.2.6 Diving bell Test: — earth monitoring systems, if applicable. — bell emergency power. — the bell emergency locating device for the bell. Determine if it has an operating frequency of 37.5 kHz. The validity date of the batteries on the transponder and strobe on the bell should be examined.
3.3.3 Outside equipment
3.3.3.1 Hyperbaric lifeboat and hyperbaric rescue chamber The hyperbaric lifeboat and hyperbaric rescue chamber shall be tested as per the relevant criteria for chambers, pressure vessels, etc. specified above. Drills shall be completed as per flag requirements.
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DNV GL AS 3.4 LARS
3.4.1 Tertiary recovery Tertiary recovery shall be demonstrated once every five (5) years.
4 Surface diving systems Section 2
4.1 Annual survey The relevant parts from SAT systems for example PVHO inspection should be followed.
4.2 Testing The ventilation bill shall be confirmed, see DNVGL-OS-E402 Ch.2 Sec.3 [4.6.1]. Chapter 3 The LARS shall be tested at 1.25 times overload, with redundancy and safety mechanisms confirmed until the basket wet bell has returned to the location where the divers can safely embark, see DNVGL-OS-E402 Ch.2 Sec.6 [2.2.2].
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DNV GL AS APPENDIX A LIST OF SOURCES TO ASSIST IN OBTAINING REFERENCE DOCUMENTS (INFORMATIVE)
1 General
Table 1 Appendix A Reference document Source
DNV GL Veritasveien 1 DNV GL standards and offshore standards N-1322 Høvik, Norway http://www.dnvgl.com
A guide to hazard and operability studies, 1979, Chemical Industries http://www.cia.org.uk/ Association Limited, London.
AS/NZS ISO 8402 quality, vocabulary: 1994
ISO 6385:2004 ergonomic principles of the design of work systems
ISO 9000 quality management
ISO/TR 10013:2001 guidelines for quality management system International Organization for Standardization, documentation Geneva http://www.iso.ch/ ISO 10 380, BS 6501-1:2004 pipework, corrugated metal hoses and hose assemblies
ISO 10474 steel and steel products: inspection documents
ISO 13628-5 subsea umbilicals
BS 4778-2:1991 quality vocabulary, quality concepts and related British Standards Institute definitions, British Standards Institute, London. http://www.bsi-global.com/
ISO/IEC 1706:2012 conformity assessment, requirements for bodies certifying products, processes and services International Organization for Standardization, ISO 2503 gas welding equipment, pressure regulators and pressure Geneva. regulators with flow-metering devices for gas cylinders used in welding, cutting and allied processes up to 300 bar (30 MPa) http://www.iso.ch/
EN 10204 metallic products, types of inspection documents.
ASME VIII div.1 American Society of Mechanical Engineers ASME PVHO-1 safety standard for pressure vessels for human http://www.asme.org/ occupancy
API codes for hoses American Petroleum Institute API 17E specification for subsea production control umbilicals. http://api-ec.api.org/
IMO code of safety for diving systems, 1995 resolution A.831(19) International Maritime Organization IMO guidelines and specifications for hyperbaric evacuation http://www.imo.org/ systems, 1991 resolution A.692(17)
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DNV GL AS Reference document Source
IMO MSC.1/Circ.1580 (16 June 2017) Guidelines for vessels and units with dynamic positioning (DP) systems.
IMO resolution A.809(19) see SOLAS regulations III/6.2.1
IMO resolution MSC.61(67) FTP code: international code for application of fire test procedures: resolution MSC.61(67): including
fire test procedures referred to in and relevant to the FTP code Appendix A
IMO resolution A.468 (XII) code on noise levels on-board ships.
IMO MODU code Ch.6
International Convention for the Safety of Life at Sea (SOLAS) 1974
AODC and IMCA documents http://www.imca-int.com/
International Electro Technical Commission's publication No.79-10 http://www.iec.ch/
NORSOK standard U-100 manned underwater operations http://www.nts.no/norsok/
PD 5500:2009 specification for unfired fusion welded pressure British Standards Institute vessels http://www.bsi-global.com/
SAE J 517 hydraulic hose
EN 853 rubber hoses and hose assemblies, wire braid reinforced Society of Automotive Engineers hydraulic type, specification, 856 rubber hoses and hose assemblies, rubber-covered spiral wire reinforced hydraulic type, http://www.sae.org/ specification, 857 rubber hoses and hose assemblies, wire braid reinforced compact type for hydraulic applications, specification
National Fire Protection Association (NFPA) 1 Batterymarch Park P.O. Box 9101 National Fire Protection Agency codes Quincy, MA 02269-9101 USA Telephone: +1 617 770-3000 Fax: +1 617 770-0700 www.nfpa.org
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DNV GL AS APPENDIX B PRESSURE CONTAINING EQUIPMENT SUMMARY
1 General With the exception of volumetric expansion tests, pressure testing (pneumatic or hydraulic) exceeding the maximum allowable working pressure (MAWP) is not required as a means to verify the in service status of pressure vessels being a part of diving systems in class with DNV GL.
Guidance note: Appendix B Pressure testing above MAWP stresses the pressure vessel significantly and may worsen an existing fatigue defect without detecting it. Doing such tests with gas, when the defect detection technique is failure of the pressure vessel itself, is not a safe inspection technique. It should also be noted that the service profile of pressure vessels within a diving system places them at increased risk of internal corrosion but not fatigue. Hence while there is a need for more frequent internal inspections increasing the frequency of testing for fatigue type damages is not required.
---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--- The following (main) categories of pressure vessels are found in a diving system: — Pressure vessels for human occupancy (PVHO), including diving bells. — Manways or trunks used to pass between PVHOs and bells. — Utility pressure vessels such as: — hot water and other tanks — air and gas volume tanks — compressor filter housing. — Seamless gas cylinders: — gas storage tubes for the system and HES — gas bottles outside the bell(s).
1.1 First year periodic survey First year periodic survey, all pressure vessels and piping shall be visually examined externally on an annual basis. Chambers and diving bells shall be visually examined internally also.
1.2 Second year periodic survey All pressure vessels shall be visually examined internally as well as externally at two yearly intervals, excepting the gas storage tubes in the DSVs on-board gas bank and piping. The latter are examined externally only and internally every five (5) years.
1.3 10-year periodic survey In addition to the visual inspection, all pressure vessels that are not monitored under [1.3.1] shall be tested every 10-year of service. For further details please see the applicable details for the various pressure vessels below.
1.3.1 Chamber and bells For systems having digital pressure monitoring with a record of the actual cycles experienced, testing shall be invoked when 20% of the design fatigue life have been reached for the worst-case chamber. For systems not able to provide documentation of the pressure cycling since new, testing shall be invoked at a 10-year cycling basis.
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DNV GL AS Guidance note: Pressure vessels connected to chambers and bells may be included in the same survey arrangement based upon DNVGL-OS-E402 Ch.3 Sec.2 [4.1.4].
---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---
1.3.1.1 Testing A leak test to the MAWP shall be carried out. Upon a successful leak test, eddy current testing (ET) shall be
carried out of the external surface of the external welds of view ports, locks and manways. Appendix B The ET procedure shall be based on ISO 17643. Acceptance criteria shall be EN ISO 23278, acceptance level 2X (MT testing criteria) The ET procedure shall be sent in for approval prior to commencement of inspection. For pressure vessels made of duplex steels, the procedure shall reflect this with respect to reference block, parameters or possibly equipment. If no cracklike defect(s) are detected, the pressure vessel is accepted for another period.
1.3.1.2 Downgrading In lieu of ET, the system may be downgraded by dividing the design MAWP with the applicable safety factor taken from the design code. This new MAWP will then apply to the system. Guidance note: The test pressure TP is an engineering concept that relates to a certain factor compared to yield (normally 90% of yield). The MAWP is a policy concept relating to a safety factor determined by standards, codes or statutory regulations. In one case, it may be 1.3 whereas in another it might be 1.5. It may also differ between the design codes and the materials applied in the manufacture of the pressure vessel.
---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--- Downgrading of chambers may be requested either: — after installation of windows with a lower design pressure than the chamber — after any other causes which may or may not imply a reduction of strength of the pressure vessel. The procedure necessitates the following alterations and recordings: a) The pressure vessel shall be marked at a location close to the original marking and the original marking shall be covered. b) The filed copies of the certificates shall be marked. c) Issue of an MO (memo to owners). d) The memo shall include the necessary information as to: — the new maximum operating pressure of the diving system — the reasons behind the downgrading. This is done to simplify the procedure when the owner might, at a later stage, want to re-certify the pressure vessel to its original operating pressure.
1.3.2 Other pressure vessels Pressure vessels being a part of other systems such as compressors, reclaim systems and hot water systems, shall follow the systematics defined by the manufacturer. Other welded pressure vessels, such as the sewage tanks and scrubber pots, shall follow the regime for chambers and bells with respect to visual testing. If mechanical damage or corrosion is detected, a new evaluation based on the design standard shall be carried out based on the actual data. Follow up shall be defined for each case.
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DNV GL AS 1.3.3 Seamless gas cylinders Pressure testing using acoustic emission in accordance with EN 16753. As an alternative, standard hydrostatic pressure testing carried out in accordance with Annex D in ISO 18119 shall be carried out. Acceptance criteria is given in the applicable design standard for the cylinder. Guidance note: It is not accepted to change back to testing in accordance with Annex D in ISO 18119 for cylinders failing testing in accordance
with EN 16753. Appendix B
---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---
Table 1 Summary
Item New Annual Every 2nd year Every 10th year
Visual (internal Visual (internal and external) and external) Testing as Chambers Visual (internal required by the Leak test and bells and external) design standard Leak test NDT of predefined welds
Testing as Visual (internal Gas bottles Visual (internal required by the Visual (external) and external) underwater and external) design standard Pressure testing
Visual (internal Visual (external) and external) Gas storage Testing as tubes and required by the Visual (external) Volumetric expansion HES bottles design standard Leak test test or AE testing Leak test
Visual (internal Visual (internal Air and gas Testing as and external) and external) volume required by the Visual (external) tanks and Leak test design standard sewage tanks Leak test NDT
Testing as Hot water and Visual (internal Visual (internal required by the Visual (external) other tanks and external) and external) design standard
Visual, external
Leak test Visual (external) Visual (external) Pipework Visual (external) Leak test Leak test Hydro-test, safety factor 1.5
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DNV GL AS CHANGES – HISTORIC
July 2017 edition This document replaces the December 2015 edition of DNV-DSS-105 and the April 20017 edition of DNV-RP- E401. Changes – historic
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DNV GL AS About DNV GL DNV GL is a global quality assurance and risk management company. Driven by our purpose of safeguarding life, property and the environment, we enable our customers to advance the safety and sustainability of their business. We provide classification, technical assurance, software and independent expert advisory services to the maritime, oil & gas, power and renewables industries. We also provide certification, supply chain and data management services to customers across a wide range of industries. Operating in more than 100 countries, our experts are dedicated to helping customers make the world safer, smarter and greener.
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