DNVGL-SE-0476 Offshore Riser Systems
SERVICE SPECIFICATIONDNVGL-SE-0476Edition August 2017Offshore riser systemsThe electronic pdf version of this document, available free of chargefrom http://www.dnvgl.com, is the officially binding version.DNV GL AS
FOREWORDDNV GL service specifications contain procedural requirements for obtaining and retainingcertificates and other conformity statements to the objects, personnel, organisations and/oroperations in question. DNV GL AS August 2017Any comments may be sent by e-mail to rules@dnvgl.comThis service document has been prepared based on available knowledge, technology and/or information at the time of issuance of thisdocument. The use of this document by others than DNV GL is at the user's sole risk. DNV GL does not accept any liability or responsibilityfor loss or damages resulting from any use of this document.
GeneralThis document supersedes the October 2010 edition of DNV-OSS-302.The purpose of the revision of this service document is to comply with the new DNV GL document referencecode system and profile requirements following the merger between DNV and GL in 2013. Changes mainlyconsist of updated company name and references to other documents within the DNV GL portfolio.Some references in this service document may refer to documents in the DNV GL portfolio not yet published(planned published within 2017). In such cases please see the relevant legacy DNV or GL document.References to external documents (non-DNV GL) have not been updated.Editorial correctionsIn addition to the above stated changes, editorial corrections may have been made.Service specification — DNVGL-SE-0476. Edition August 2017Page 3Offshore riser systemsDNV GL ASChanges - currentCHANGES – CURRENT
Changes – current. 3Section 1 General. 51.1 General. 51.2 Background. 91.3 Definitions.111.4 Abbreviations. 141.5 Other references. 16Section 2 Technical approach.172.1 General. 172.2 Global analysis.172.3 Detailed component analysis. 212.4 Structural reliability analysis. 232.5 Special analyses.232.6 Fatigue assessment. 252.7 Drilling, completion and workover. 262.8 Flexible risers and umbilicals. 262.9 Material technology and failure investigation. 292.10 Marine operations. 30Section 3 Service overview. 333.1 General. 333.2 Technical advisory services. 333.3 Verification services.363.4 Certification services. 473.5 Research and development services. 49Appendix A Applicable software.51A.1 General. 51Changes – historic. 53Service specification — DNVGL-SE-0476. Edition August 2017Page 4Offshore riser systemsDNV GL ASContentsCONTENTS
SECTION 1 GENERAL1.1 General1.1.1 Introduction1.1.1.1 DNV GL provides various services related to dynamic riser systems, where the word dynamic isreferring to a non-stationary riser. In the notation dynamic riser systems, the following are included:—————metallic risers (i.e. steel, titanium)composite risersflexible pipesumbilicals (i.e. individual or piggy-back)loading hoses.1.1.1.2 The DNV GL services include technical advice/assistance (consultancy activities) researchand development services, in addition to more traditional design verification/product certification. Theverification and certification services are carried out with basis in rules, standards, regulations and customerrequirements.1.1.1.3 This service specification (SE) provides criteria for and guidance to the above-mentioned services foreither complete dynamic riser systems, or for separate/self-contained components of riser systems.1.1.1.4 DNV GL is a recognised provider of technical advisory services, which can be directly connected withthe development and design of deepwater riser systems.1.1.1.5 For verification and certification, this service specification for dynamic riser systems aims at usingthe same principles/approaches as used in the service specification for submarine pipeline systems (DNVGLSE-0475).1.1.2 ObjectivesThe objectives of this document are to:— describe DNV GL’s overall competence and experience related to dynamic riser systems.— describe DNV GL’s technical advisory-, verification- and certification services for dynamic riser systems.Guidance note:DNV GL will use this service specification as a reference document in writing bids/proposals to the clients. This will provide a clearand uniform understanding of the scope of work to be carried .1.3 Organisation of this service specification1.1.3.1 This document consists of three sections and one appendix:— This section; providing general scope of the present document, informative background information,definitions, abbreviations and references.— Sec.2; providing information about DNV GL's competence, experience and technical approach used in theirdynamic riser services.— Sec.3; providing information/specifications about DNV GL’s services to dynamic riser systems.— App.A; provides an overview of applicable software programs used by DNV GL.Service specification — DNVGL-SE-0476. Edition August 2017Page 5Offshore riser systemsDNV GL AS
1.1.4 Structure of riser-related DNV GL documents1.1.4.1 Reference is made to the foreword to this document. From the document structure described therein,documents relating to riser systems consist of a three-level hierarchy with these main features:— Principles and procedures related to DNV GL’s services are separate from technical requirements and aredescribed in DNV GL service specifications.— Technical requirements are issued as self-contained DNV GL standards.— Associate product documents are issued as DNV GL recommended practices.Guidance note:Product documents issued under previous document structures may be termed classification notes or t-e---1.1.4.2 The 3-level hierarchy is designed with these objectives:— Service specifications present the scope and extent of DNV GL’s services.— DNV GL standards are issued as neutral technical standards to enable their use by national authorities, asinternational codes and as company or project specifications without reference to DNV GL’s services.— The recommended practices convey DNV GL’s interpretation of safe and sound engineering practice forgeneral use by the industry.Guidance note:The latest revision of all official DNV GL publications may be found on the document list on the DNV GL’s web site: -o-t-e---1.1.5 DNV GL applicable standards and specifications1.1.5.1 The following DNV GL standards and specifications relevant for dynamic risers apply (not limited to):Table 1-1 DNV GL offshore rules and service ore drilling and support unitsDNVGL-RU-OU-0102Floating production, storage and loading unitsDNVGL-SE-0475Verification and certification of submarine pipelinesTable 1-2 DNV GL standardsReferencesTitleDNVGL-OS-C102Structural design of offshore shipsDNVGL-OS-C103Structural design of column stabilised units - LRFD methodDNVGL-OS-C104Structural design of self-elevating units - LRFD methodDNVGL-OS-C105Structural design of TLPs - LRFD methodDNVGL-OS-C106Structural design of deep draught floating units - LRFD methodDNVGL-OS-E101Drilling plantDNVGL-OS-E201Oil and gas processing systemsService specification — DNVGL-SE-0476. Edition August 2017Page 6Offshore riser systemsDNV GL AS
ReferencesTitleDNVGL-ST-F101Submarine pipeline systemsDNVGL-ST-F201Dynamic risersTable 1-3 DNV GL recommended practice (RP)ReferencesTitleDNVGL-RP-A203Technology qualificationDNVGL-RP-B401Cathodic protection designDNVGL-RP-C203Fatigue design of offshore steel structuresDNVGL-RP-C205Environmental conditions and environmental loadsDNVGL-RP-C211Structural reliability analysis(replacing DNV Classification Notes No. 30.6)DNVGL-RP-C212Offshore soil mechanics and and geotechnical engineering(replacing DNV Classification Notes No. 30.4)DNVGL-RP-F101Corroded pipelinesDNVGL-RP-F105Free spanning pipelinesDNVGL-RP-F106Factory applied external pipeline coatings for corrosion controlDNVGL-RP-F113Pipeline subsea repairDNVGL-RP-F203Riser interferenceDNVGL-RP-F204Riser fatigueDNVGL-RP-F205Global performance analysis of deepwater floating structuresDNVGL-RP-N101Risk management in marine and subsea operationsDNVGL-RP-O501Managing sand production and erosionTable 1-4 DNV GL class guidelines (CG)ReferencesTitleDNVGL-CG-0051Non-destructive testing(replacing DNV Classification Notes No. 7)Table 1-5 DNV GL class programmesReferencesTitleDNVGL-CP-0338Type approval schemeDNV GL class programmes for type approvalDNV GL class programmes for approval of manufacturersService specification — DNVGL-SE-0476. Edition August 2017Page 7Offshore riser systemsDNV GL AS
1.1.5.2 The standard DNVGL-ST-F201 covers all aspects related to design and analysis of metallic andcomposite dynamic risers. DNVGL-ST-F201 is a result of the joint industry project Design Proceduresand Acceptance Criteria for Deepwater Risers. DNVGL-ST-F201 applies to all new-built all-metallic risersystems and may also be applied for modification, operation and upgrading of existing corresponding risers.The standard is applicable for both permanent operations (e.g. production and export/import) as wellas temporary operations (e.g. drilling and completion/workover). DNVGL-ST-F201 for dynamic risers iscompatible with DNVGL-ST-F101 for submarine pipeline systems. The main benefits of DNVGL-ST-F201 are:— consistent safety level— flexible modern design principles (LRFD method, which is recommended for optimal design of deep waterriser systems)— cost effective design— guidance and requirements for efficient global analyses— allowance for use of innovative techniques and procedures.1.1.5.3 The DNV GL standards are subject to continuous development to reflect the state-of-the-artconsensus on accepted industry practice.1.1.6 Other applicable standards and specifications1.1.6.1 DNV GL services can be carried out by using our own standards and or specifications or any otherapplicable recognised standard or project specific specification and or requirements.1.1.6.2 Mixing of codes or standards for each system and equipment is in general to be avoided due to thepossible differences in safety philosophies. Deviations from the code must be specially noted and approved (ifnecessary).Guidance note:Most standards are a coherent collection of requirements for all the relevant aspects of a riser system. These aspects, e.g. loadand resistance, are normally among themselves adjusted to give an overall acceptable safety level. To pick requirements fromdifferent standards can then easily result in unpredictable (low) levels of --1.1.6.3 The following API publications are applicable to risers (not limited to):Table 1-6 API recommended practiceReferencesTitleAPI RP 2RDDesign of Risers for Floating Production Systems (FPSs) and Tension-Leg Platforms (TLPs)API RP 17BRecommended Practice for Flexible PipeAPI RP 17CRecommended Practice on TFL (Through Flow Line)API RP 17IInstallation Guidelines for Subsea UmbilicalsAPI RP 16QRecommended Practice for Design, Selection, Operation and Maintenance of Marine Drilling RiserSystemsTable 1-7 API specificationsReferencesTitleAPI SPEC 17JSpecification for Unbonded Flexible PipeAPI SPEC 17GDesign and Operation of Completion Workover Riser SystemsService specification — DNVGL-SE-0476. Edition August 2017Page 8Offshore riser systemsDNV GL AS
ReferencesTitleAPI SPEC 17KSpecification for Bonded Flexible PipeAPI SPEC 7KSpecification for Drilling EquipmentAPI SPEC 16RSpecification for Marine Drilling Riser CouplingsAPI SPEC 17ESpecification for Subsea Production Control Umbilical1.1.6.4 For material and test methods, the American Society for Testing and Materials (ASTM) has a list ofrelevant specifications.1.1.6.5 The following ISO standards are applicable (not limited to):Table 1-8 ISO standardsReferencesTitleISO/FDIS 2394General Principles on Reliability for StructuresISO/CD 13628-2Petroleum and natural gas industries – Design and operation of subsea production systems –Part 2: Flexible pipe systems for subsea and marine applicationsISO/CD 13628-5Petroleum and natural gas industries - Design and operation of subsea production systems -Part 5: Subsea umbilicalsISO/CD 13628-7Petroleum and natural gas industries – Design and operation of subsea production systems –Part 7: Completion/workover riser systems1.1.6.6 In addition to the above mentioned standards or specifications, relevant ASME (American Society ofMechanical Engineers) standards or codes apply.1.2 Background1.2.1 Introduction1.2.1.1 The DNV GL multidisciplinary competence throughout the company is located at different sectionsor departments and even in different countries. The main objective of this document is to present the overallDNV GL competence and experience and to describe how DNV GL applies these assets in the services offeredin relation to dynamic riser systems.1.2.1.2 DNV GL is actively involved in joint industry projects (JIP) and research and development (R&D)projects. The experience and knowledge gained from these projects are of great value for the DNV GLservices rendered.1.2.1.3 DNV GL can through its multidiscipline competence directly engage in technology development andassessment of various riser concepts. This is outlined in some more detail in Sec.2 of this SE.1.2.1.4 New challenges arise when moving into deeper waters. DNV GL has been heavily involved in andgained valuable experiences from several developments in the Gulf of Mexico and West of Africa since themid 1990’s. DNV GL is thus qualified to assist operators and designers to manage the risk associated with thenew deepwater challenges through early project involvement.Service specification — DNVGL-SE-0476. Edition August 2017Page 9Offshore riser systemsDNV GL AS
1.2.2 Examples of dynamic riser systems1.2.2.1 The transport of hydrocarbons from a subsea well to or via a production/storage unit positioned atthe sea surface may be conducted by a variety of riser configurations depending on key field parameters,such as environmental conditions, platform concept, production rates, well pressure/temperature, waterdepth, flow assurance, installation issues etc. Also for other applications like injection of gas or producedwater into the well or for export of hydrocarbons, riser systems similar to the production riser may be used.The following categories of risers are typically used for exploitation of hydrocarbons:—————————production riserinjection risergas lift riserservice riserexport/import risercompletion/workover risermarine drilling riser systemsubsea control umbilicalintegrated production umbilical.These categories differ with respect to typical dimensions, cross-sectional composition, type of operation,functional requirements and design load conditions.1.2.2.2 Some of the following characteristic riser designs can be identified to cover the above mentionedapplications:1.2.2.3 Top tensioned riser (TTR); vertical riser supported by a top tension in combination with boundaryconditions that allows for relative riser/floater motions in vertical direction, i.e. by use of heave compensationsystem. The intended (idealised) behaviour is that the applied top tension should maintain a constant targetvalue regardless of the floater motion. The capacity of relative riser/floater motion in vertical direction(stroke) in addition to applied top tension is the essential design parameter governing the mechanicalbehaviour as well as the application range. TTR’s are applicable for all functional purposes as mentionedabove (excl. umbilical) and will hence represent an attractive alternative for floaters with rather small heavemotion.1.2.2.4 Compliant riser; compliant riser configurations are designed to absorb floater motions by change ofgeometry, without use of heave compensation systems. Compliant risers are mainly applied as production,export/import and injection risers. The required flexibility is for conventional water depths normally obtainedby arranging unbonded flexible pipes in one of the ‘classical’ compliant riser configurations: Steep S, LazyS, Steep Wave, Lazy Wave, Pliant Wave or Free Hanging (catenary). An example of a “non-classical” riserconfiguration is the compliant vertical access riser (CVAR). In deep water it is also possible to arrangemetallic pipes in compliant riser configurations. Critical locations on compliant risers are typically the wavezone, hog –and sag bends, touch down area at seafloor and at the terminations to rigid structures, e.g. I- orJ-tubes.1.2.2.5 Hybrid riser; the hybrid riser configuration is a combination of the tensioned and the compliant riserin an efficient way. A typical configuration is a vertical/free hanging riser from a submerged buoy to seabedwith a compliant riser from the buoy to the FPS. Hybrid risers are mainly applied as production, export/import and injection risers. A riser tower is an assembly of vertical risers from seabed connected to the FPSwith compliant risers. The vertical riser assembly is kept upright by various methods (e.g. truss supportstructure, distributed buoyancy on the risers, buoyancy tanks).Service specification — DNVGL-SE-0476. Edition August 2017Page 10Offshore riser systemsDNV GL AS
1.3 Definitions1.3.1 General1.3.1.1 The definitions in DNVGL-ST-F201 also apply to this SE.1.3.1.2 The most important definitions from DNVGL-ST-F201 applied in this SE are repeated. They aremarked (DNVGL-ST-F201) between the word and its definition.1.3.2 Verbal formsTable 1-9 Definitions of verbal formsTermDefinitionshallverbal form used to indicate requirements strictly to be followed in order to conform to thedocumentshouldverbal form used to indicate that among several possibilities one is recommended as particularlysuitable, without mentioning or excluding others, or that a certain course of action is preferredbut not necessarily requiredmayverbal form used to indicate a course of action permissible within the limits of the document1.3.3 DefinitionsTable 1-10 TermsTermDefinitionbuoyancy modules(DNVGL-ST-F201)structure of light weight material, usually foamed polymers, strapped or clamped to theexterior of riser joints, to reduce the submerged weight of the risercertificationused in this document to mean all the activities associated with the process leading up to acertificateGuidance note:In this SE when certification is used it designates the overall scope of work or multipleactivities for the issue of a certificate, whilst verification is also used for single activitiesassociated with the work. This in essence means that certification is verification for which thedeliverable includes the issue of a certificate.Other (related) definitions are:BS 4778: Part 2: certification: the authoritative act of documenting compliance withrequirements.EN 45011: certification of conformity: action by a third party, demonstrating that adequateconfidence is provided that a duly identified product, process or service is in conformity with aspecific standard or other normative document.ISO 8402: 1994: verification: confirmation by examination and provision of objectiveevidence that specified requirements have been -e---clientDNV GL’s contractual partner, it may be the purchaser, the owner or the contractorService specification — DNVGL-SE-0476. Edition August 2017Page 11Offshore riser systemsDNV GL AS
TermDefinitioncompletion/workover riser(DNVGL-ST-F201)temporary riser used for completion or workover operations and includes any equipmentbetween the subsea tree/tubing hanger and the workover floaters tensioning systemcompliant risera riser designed to absorb floater motions by change of geometry, without use of heavecompensation systemsconsultingtechnical advisory service offered during any phase of a projectdesignall related engineering to design the riser including structural as well as material andcorrosion protectiondesign phasean initial riser phase that takes a systematic approach to the production of specifications,drawings and other documents to ensure that the riser system meets specifiedrequirements (including design reviews to ensure that design output is verified againstdesign input requirements)design checks(DNVGL-ST-F201)design checks are investigations of the structural safety of the riser under the influenceof load effects (design load cases with respect to specified limit states, representing oneor more failure modes, in terms of resistance of relevant structural models obtained inaccordance with specified principles)design verification report(DVR)a document issued to confirm that the product/process has been completed in accordancewith specified requirementsdrilling riser(DNVGL-ST-F201)a riser utilised during drilling and workover operations and isolates any wellbore fluidsfrom the environmentThe major functions of drilling riser systems are to provide fluid transportation to andfrom the well; support auxiliary lines, guide tools, and drilling strings; serve as a runningand retrieving string for the BOP. Drilling risers may also be used for well completion andtesting.effective tension(DNVGL-ST-F201)the axial wall force (axial pipe wall stress times area) adjusted for the contributions fromexternal and internal pressureexport/import riser(DNVGL-ST-F201)export/import risers transfer the processed fluids from/to the floater (structure to/fromanother facility, which may include another platform/floater or pipeline)fabricationactivities related to the assembly of objects with a defined purposefatigue(DNVGL-ST-F201)cyclic loading causing degradation of the materialflex joint(DNVGL-ST-F201)a laminated metal and elastomer assembly, having a central through-passage equal to orgreater in diameter than the interfacing pipe or tubing bore, that is positioned in the riserstring to reduce the local bending stresses (typical installation at connection to floater/seafloor)flexible riserrisers used to take large motionsThe flexible riser combines low bending stiffness with high axial tensile stiffness by use ofhelical armouring layers and polymer sealing layers.floater(DNVGL-ST-F201)buoyant installation, which is floating or fixed to the sea bottom by mooring systems intemporary or permanent phases, e.g. TLP, Ship, Semi, Spar, Deep Draft Floater etc.global analysis(DNVGL-ST-F201)analysis of the complete riser systemhybrid risera combination of tensioned riser and compliant riserService specification — DNVGL-SE-0476. Edition August 2017Page 12Offshore riser systemsDNV GL AS
TermDefinitioninstallation(DNVGL-ST-F201)the operation related to installing the riser system, such as running of riser joints, landingand connecting or such as laying, tie-in, etc. for a dynamic riserlimit state(DNVGL-ST-F201)the state beyond which the riser or part of the riser no longer satisfies the requirementslaid down to its performance or operationExamples are structural failure (rupture, local buckling) or operations limitations (stroke orclearance).load(DNVGL-ST-F201)the term load refers to physical influences which cause stress, strain, deformation,displacement etc. in the riserload and resistance factordesign (LRFD)(DNVGL-ST-F201)design format based upon a limit state and partial safety actor methodologyThe partial safety factor methodology is an approach where separate factors are appliedfor each load effect (response) and resistance term.low frequency response(DNVGL-ST-F201)motion response at frequencies below wave frequencies or near surge, sway and yaweigenperiods for the floaterLF motions typically have periods ranging from 30 to 300 seconds.manufacturemaking of articles or materials, often in large volumesIn relation to risers, refers to activities for the production of riser joints, end terminations,components and application of coating.ovalisation(DNVGL-ST-F201)the deviation of the perimeter from a circleThis has the form as an elliptic cross section. The numerical definition of out of roundnessand ovalisation is the same.permanent riser(DNVGL-ST-F201)the deviation of the perimeter from a circleThis has the form as an elliptic cross section. The numerical definition of out of roundnessand ovalisation is the same.production/injection riser(DNVGL-ST-F201)production risers transport fluids produced from the reservoirInjection risers transport fluids to the producing reservoir or a convenient disposalor storage formation. The production riser may be used for well workover, injection,completion and other purposes.riser component(DNVGL-ST-F201)a ny part of the riser system that may be subjected to pressure by the internal fluidThis includes items such as flanges, connectors, stress joints, tension joints, flex-joints,ball joints, telescopic joints, slick joints, tees, bends, reducers and valves.riser joint(DNVGL-ST-F201)a joint for metallic risers consists of a pipe member mid section, with riser connectors ateach end.Riser joints are typically provided in 30 ft. to 50 ft. (9.14m to 15.24m) lengths. Shorterjoints, pup joints, may also be provided to ensure proper space-out.riser system(DNVGL-ST-F201)a riser system is considered to comprise the riser, all integrated riser components andcorrosion protection systemriser tensioner system(DNVGL-ST-F201)a device that applies a tension to the riser string while compensating for the relativevertical motion (stroke) between the floater and riserTension variations are controlled by the stiffness of the unit.risk analysis(DNVGL-ST-F201)analysis including a systematic identification and categorisation of risk to people, theenvironment and to assets and financial interestsslender structuresslender structures are used as a collective term for risers, tendons and mooring linesService specification — DNVGL-SE-0476. Edition August 2017Page 13Offshore riser systemsDNV GL AS
TermDefinitionstress joint(DNVGL-ST-F201)a specialised riser joint designed with a tapered cross section, to control curvature andreduce local bending stressestechnical reporta document describing background, theory, methodology, input and results from analysesor other work carried outtensioned riser(DNVGL-ST-F201)a riser, which is essentially kept straight and tensioned in all parts, by applying a toptension to ittemporary riser(DNVGL-ST-F201)a riser which is used intermittently for tasks of limited duration, and which can beretrieved in severe environmental conditions, essentially marine/drilling risers andcompletion/workover risersumbilicalan umbilical is used for example for subsea control, data communication andtransportation of production system service fluids and/or utility suppliesThe umbilical consists of a group of cables (e.g. electrical, optical fibre) and hoses cabledtogether for flexibility, over sheathed and or armoured for mechanical strength.verificationan examination to confirm that an activity, a product or a service is in accordance withspecified requirementsverification commentssheets (VerCom)are regarded as a systematic way of documenting the resolution process between theparties involvedwave frequency response(DNVGL-ST-F201)response at the frequencies of incident wavesworking stress design(WSD) (DNVGL-ST-F201)design method where the structural safety margin is expressed by one central safetyfactor for each limit stateThe central safety factor is the ratio between a resistance and the load effect.1.4 AbbreviationsTable 1-11 AbbreviationsAbbreviationDescriptionALSaccidental limit stateAPIAmerican Petroleum InstituteASMEThe American Society of Mechanical EngineersASTMThe American Society for Testing and MaterialsCAPEXcapital expenditureCFDcomputational fluid dynamicsCVARcompliant vertical access riserDVRdesign verification reportFDfrequency domainFEfinite elementFEAfinite element analysisService specification — DNVGL-SE-0476. Edition August 2017Page 14Offshore riser systemsDNV GL AS
AbbreviationDescript
DNVGL-RP-F113 Pipeline subsea repair DNVGL-RP-F203 Riser interference DNVGL-RP-F204 Riser fatigue DNVGL-RP-F205 Global performance analysis of deepwater floating structures DNVGL-RP-N101 Risk management in
General design rules for riser necks used in iron castings; a. general riser b. side riser for plates c. top round riser Risers and Riser Design . Mech 423 #2 2 Figure 5.10 (a) Castings with blind feeders, F2 is correctly vented but has mixed results on sections S3 . metal velocity and turbulence
S4 / S6 Riser Kits Installation 9329-66144-00 REV A 1 S4/S6 Riser Kit Installation This document provides instructions for inst alling Riser Kits in an Avid S4 or S6 c ontrol surface. Riser Ki ts raise modules whe n a better viewing and interaction angle is desi red. Riser Kits for S4 and S6 include 1- bay and 2-bay kits.
DNV GL offshore standards contain technical requirements, principles and acceptance criteria related to classification of offshore units. . DNVGL-RP-B401 Cathodic protection design DNVGL-RP-C201 Buckling strength of plated structures D
connected drilling riser. A typical drilling riser stack-up is shown in Figure 1. Waves cause vessel surge and sway motions which are then transferred to the top of the drilling riser. Additionally, there is direct hydrodynamic load on the riser from the waves. Vortex-induced vibration (VIV) is another source of riser motions.
API RP 2SK API RP 2SM API RP 2I DNVGL-OS-E301 DNVGL-OS-E302 DNVGL-OS-E303 DNVGL-OS-E304 Guidelines for Offshore Marine Operations (GOMO) MODU Mooring in Australian Tropical Waters Guidelines Page 12 of 55 3 RISK SCREENING 3.1 Introduction The purpose of this section is to provide guidance on
k. Riser clamps for bare cast iron pipe shall be Anvil Fig. 261 steel riser clamps. Locate under coupling or bell of pipe. l. Riser clamps for bare plastic pipe shall be Anvil Fig. 261 steel riser clamps. m. Riser clamps for bare stainless steel
the looped fire line to provide for isolation of the fire line. 5. fire sprinkler lines shall have a riser control piv for each individual riser. the piv's shall be located as close to the riser as practical. the riser control piv's may be eliminated when fd105 is used. fire sprinkler (fs) system riser (fd105) shall be shown on 6.
www.2id.korea.army.mil 2 Indianhead August 13, 2010 “Jeju Island, it takes about a half day to travel, so on a long weekend you can spend three full days touring, exploring, and enjoying yourself.” Pfc. Reginald Garnett HHC, 1-72th Armor OpiniOn “Gangneung is a great place to visit. It has a beautiful beach, Gyeongpo Beach, where many .
