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Document no. 13/90242-5 - ETS-21 v. 3
Offshore Substation
Materials and Fabrication of Steel for Topside andSub-Structure
ETS-21 Rev. 3
t e c h
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i c a l
s t a n
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a r d s
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Revision survey
Document title Materials and Fabrication of Steel for Topside and Sub-Structures.
Document no. 13/90242-5
Target group Fabrications Contractors and Designer for Offshore substations.
RevisionDocumentstatus
Writer Reviewer Approver
Init Date Init Date Init Date
1 Approved N/A 12.10.09 N/A 12.10.09 AGS 12.10.09
2 Approved xomo 22.11.2012 GKY, SVR 10.10.2012 POD 03.12.20123 Approved
SBG,xomo
28.11.2014POD, SBG,XHFN, OLJ
16.12.2014 OLJ 16.12.2014
Minor alterations, type errors, rephrases' etc. where the meaning of the text is leftunchanged are not shown.
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Document no. 13/90242-5 - ETS-21 v. 3
Table of contents
1. Scope ............................................................................................... 1
2. References ....................................................................................... 1
2.1 Codes and Standards ............................................................................ 1 2.2 Energinet.dk Technical Standards........................................................... 3
3. Definitions and abbreviations .......................................................... 3
3.1 Definitions ........................................................................................... 3 3.2 Abbreviations ...................................................................................... 4
4. General ............................................................................................ 5
4.1 Quality and HSE - Project Plans ............................................................. 5
4.2
Structural categories ............................................................................ 5
5. Structural Materials ......................................................................... 5
5.1 General............................................................................................... 5 5.2 Steel Material ...................................................................................... 5
5.2.1 Chemical Properties ...................................................................... 6 5.2.2 Bolting Material ............................................................................ 6 5.2.3 Internal Soundness ....................................................................... 7
5.3 Structural Categories ............................................................................ 7 5.3.1 Material Certificates and Markings ................................................... 8
5.4 Fabrication of Welded Structural Members ............................................... 8 5.5 Standard Tubulars and Sections ............................................................. 8 5.6 Stairs, Handrails and Grating for Topside ................................................ 8
5.7
Stairs and grating materials for Sub-structure ......................................... 8
5.8
Platform Doors. ................................................................................... 9
6. Structural steel dimensions ............................................................. 9
6.1 Tubular dimensions and tolerances ......................................................... 9 6.2 Sections - dimensions and tolerances ..................................................... 9 6.3 Steel plates ....................................................................................... 10 6.4 Rectangular/square hollow sections ...................................................... 10
7. Structural fabrication ..................................................................... 10
7.1 Storage and handling of steel materials ................................................ 10 7.1.1 Identification system ................................................................... 10 7.1.2 Alignment .................................................................................. 11
7.2 Structural sections and plates .............................................................. 11 7.3
Scaffolding hooks ............................................................................... 11
7.4 Bolted connections ............................................................................. 11 7.4.1 Bolts in shear and tension connections .......................................... 12 7.4.2 Friction grip connections .............................................................. 12
7.5 Helidecks .......................................................................................... 12 7.6 Lifting fittings .................................................................................... 12
7.6.1 Definition ................................................................................... 12 7.6.2 Materials and Fabrication ............................................................. 13 7.6.3 Additional Requirements .............................................................. 13
7.7 Finishing of structural steel ................................................................. 14 7.8 Fabrication of non-structural steel and temporary attachments ................ 14
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7.8.1 Temporary cut-outs .................................................................... 14 7.8.2 Rat holes (Weld access hole) ........................................................ 14
7.9
Fabrication dimension tolerances ......................................................... 14
7.9.1
Tolerances for linear dimensions ................................................... 15
7.9.2 Tolerances for angular dimensions ................................................ 15 7.9.3 Tolerances for straightness, flatness and parallelism ....................... 15 7.9.4 Section ends .............................................................................. 16 7.9.5 Location of seams ....................................................................... 16 7.9.6 High-low .................................................................................... 17 7.9.7 Plates and grating ....................................................................... 17 7.9.8 Landings and stairways ............................................................... 17 7.9.9 Interface tolerance ...................................................................... 17 7.9.10 Markings Sub-structure. .............................................................. 17
8. Welding .......................................................................................... 17
8.1 Welding processes .............................................................................. 17
8.2
Qualifications of welders and welding operators ..................................... 18
8.2.1 Welding coordinator .................................................................... 18 8.2.2 Welders and operators................................................................. 18 8.2.3 Identification of welder or welding operator .................................... 18 8.2.4 Welder's or operator's record ....................................................... 18 8.2.5 Test for branch connections ......................................................... 19
8.3 Welding procedures ............................................................................ 19 8.3.1 General ..................................................................................... 19 8.3.2 Specific requirements .................................................................. 20 8.3.3 Test of the procedure welds ......................................................... 20
8.4 Production welding ............................................................................. 21 8.4.1 Welding sequences ..................................................................... 21 8.4.2 Weld preparation ........................................................................ 21
8.4.3
Weld execution ........................................................................... 21
8.4.4
Pre-heating ................................................................................ 22
8.4.5 Inter-pass temperature ............................................................... 23 8.4.6 Post weld heat treatment (PWHT) ................................................. 23 8.4.7 Weld repairs ............................................................................... 23 8.4.8 Production testing ....................................................................... 24
9. Non-destructive examination ......................................................... 24
9.1 Extent of examinations ....................................................................... 24 9.2 NDE Qualifications .............................................................................. 25
9.2.1 Examination organisation ............................................................. 25 9.2.2 Examination personnel ................................................................ 25 9.2.3 Procedures ................................................................................. 25
9.3 Execution of NDE ............................................................................... 25
9.4
NDE procedure and acceptance criteria. ................................................ 25
9.4.1 Visual (VT) procedure and acceptance criteria ................................ 25 9.4.2 Magnetic particle (MT) procedure and acceptance criteria ................ 26 9.4.3 Radiographic testing (RT) procedure and acceptance criteria ............ 26 9.4.4 Ultrasonic testing (UT) acceptance criteria ..................................... 26 9.4.5 Liquid Penetrant testing (LP) acceptance criteria ............................. 26
9.5 Execution of NDE, structural fabrication ................................................ 26 9.5.1 General ..................................................................................... 26 9.5.2 Sequence of examination ............................................................. 27 9.5.3 Surface conditions ...................................................................... 27 9.5.4 Random examination................................................................... 27
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9.5.5 Extent of examination in case of unacceptable welds ....................... 27
10.
Coating .......................................................................................... 28
11. As-built documentation .................................................................. 28
11.1 Deliverables ...................................................................................... 29
12. Appendix ........................................................................................ 30
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1.
Scope
This technical standard specifies the minimum requirements for the materials,
fabrication, testing and inspection of offshore steel structures for topsides and sub-structures (Jackets) intended for high voltage offshore transformer platforms
(Substations).
This technical standard covers also the main supporting steel structure for helideckon topside. However, the lattice structure typically integrated under the helidecks
may be preferred by Energinet.dk to be made of aluminium. For aluminiumstructures this standard refers to the DNV standard DNV-OS-E401.
This standard may only be departed from if the deviations are approved byEnerginet.dk and certifying agency or if specified on Energinet.dk approved design
drawings.
2. References
The following codes, standards and statutory regulations shall be considered as part
of this technical standard.
2.1
Codes and Standards
All regulations, codes and standards referred to in the present standard shall apply inthe latest revision applicable at the beginning of the project unless noted otherwise.
API 2B Specification for fabricated structural steel pipe
API 5L Specification for line pipe
ASME, Section V Article 7, Magnetic Particle Examination
ASME, Section V Article 9, Visual Examination
ASME, Section IX Qualification standard for welding and brazing procedures,
welders, brazes and welding and brazing operators
AWS D1.1 Structural welding code - steel
BS 7448 Part 1, Specification for fracture mechanics toughness test
DNV-OS-C101 Design of offshore steel structures (LRFD method)
DNV-OS-C401 Fabrication and testing of offshore structures
DNV-OS-E401 Offshore standard, Helicopter Decks
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DNV-OS-J201 Offshore Substations for Wind Farms
EN 287-1 Approval Testing of Welders for Fusion Welding.
EN 473 Qualification and certification of NDT personnel. Generalprinciples.
EN 970 Welding – Visual Examination of Fusion Welded Joints.
EN 1011 Recommendations for Arc Welding of Ferritic steels.
EN 1418 Welding personnel – Approval testing of welding personnel forfully mechanized and automatic welding of metallic materials
EN 10002-1 Metallic Materials - Tensile Testing - Part 1. Method of Test.
EN 10025 Hot Rolled Products of Non-Alloy Structural Steels. Technical
Delivery Conditions.
EN 10225+AC Weld able structural steels for fixed offshore structures – Technical delivery conditions
EN 10045 Metallic Materials - Charpy Impact Test.
EN 10163-1 to 3 Delivery Requirements for Surface Conditions of Hot RolledSteel Plates, Wide Flats and Section.
EN 10164 Steel Flat Products with Specified Through ThicknessProperties. Technical Conditions for Delivery.
EN 10204 Metallic Products - Types of Inspection Documents.
EN 10210 Hot Finished Structural Hollow Sections of Non-Alloy and FineGrain Structural Steels.
EN 45004 General Criteria for the Operation of Various Types of BodiesPerforming Inspection.
EN ISO 5817 Welding-Fusion-welded joints in steel, nickel, titanium and
their alloys
EN ISO 13920 Welding – General tolerances for welded constructions –
dimensions for lengths and angles – Shape and position
EN ISO 17025 General Requirements for the Competence of Testing andCalibration Laboratories
ISO 898 Part 1-6, Mechanical properties of fasteners made of carbonsteel and alloy steel
ISO 1459 Protection against corrosion by hot dip galvanizing
ISO 1461 Hot dip galvanized coatings on fabricated iron and steel articles– Specifications and test methods
ISO 3690 Welding and allied processes. Determination of hydrogencontent in ferritic arc weld metal
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ISO 7090 Plain washers, chamfered. Normal series. Project grade A
ISO 8501 Part 1-2, Preparation of steel substrates before application of
paints and related products. Visual assessment of surfacecleanliness.
ISO 1106 Recommended practice for radiographic Examination of Fusion
Welded Joints.
ISO 2553 Welds - Symbolic Representation on Drawings.
ISO 3452 NDT - penetrant inspection - general principles.
ISO 9606-2 Qualification test of welders – Fusion welding of aluminium andits alloys
ISO 15614 Specification and qualification of welding procedures for
metallic materials
BL 3-5 Statens Luftfartsvæsen, Bestemmelser om helikopterdæk på
havanlæg
2.2
Energinet.dk Technical Standards
ETS-00 Guideline for Use of Energinet.dk Technical Standards
ETS-24 Weight Monitoring and Weighing
ETS-25 Protective Coating of Steel
EDS-50-01 Engineering Reports, Drawings and Lists
EDS-02 Requirements for “As-Built” Documentation for Offshore Substations
3.
Definitions and abbreviations
3.1 Definitions
The following definitions are used in the present standard:
Employer: Energinet.dk
Employer approval: “Employer approval” or similar terms, requires approval in
writing from Energinet.dk or his representative
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3.2
Abbreviations
Within this specification the following abbreviations have been used. Abbreviations of
standards and atomic elements are though not covered.
CE: Carbon equivalent calculated according to EN 1011-2
CTOD: Crack tip opening displacement
Dnom: Nominal diameter
ET: Eddy Current
HV: Vickers hardness
IQI: Image quality indicator
+M: Delivery condition : thermo mechanical rolling
MT: Magnetic particle examination/testing
+N : Delivery condition: normalizing rolling
NDE : Non destructive examination
OD: Outer diameter
PT: Liquid penetrant examination
PWHT: Post weld heat treatment
+Q: Delivery condition: quenched and tempered
RT: Radiographic examination/testing
t: Wall thickness
UT: Ultrasonic examination
VT: Visual examination/testing
WPQR: Welding procedure qualification record
WPS: Welding procedure specification
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4.
General
All fabrication shall be carried out in accordance with agreed procedures and
drawings and shall comply with applicable codes, standards and specifications aslisted in this ETS.
Unless otherwise stated herein, the DNV standards DNV-OS-C401 “Fabrication and
testing of offshore structures” and DNV-OS-C101 “Design of offshore steel structures(LRFD method)” shall form basis for this standard.
4.1
Quality and HSE - Project Plans
Contractor shall submit a project specific quality plan to Energinet.dk for their review
and approval. The document shall as minimum contain the following information:
Detailed fabrication plan and schedule
Organisation diagram
Manpower plan
Inspection and Test Plan.
Dimension control procedure Welding preparation details and procedures NDE procedures
Qualification of NDT operators Qualification of welders HSE manual
List of major sub-contractors
4.2
Structural categories
Structural categories for selection of materials and determination of the extent ofinspection shall be in accordance with the relevant section of DNV-OS-C101.
5. Structural Materials
5.1
GeneralThe steel type grades for topside structures shall comply with the requirements listedin appendix 1A.
The steel type grades for steel Sub-structures shall comply with the requirementslisted in appendix 1B.
5.2
Steel Material
Steel type 2 can replace steel type 1 whereas steel type 4 can replace steel type 3.
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Steel types shall be applied in accordance with approved design drawings. Thefollowing table shows typical material selections.
Steel type Structural category
Special Primary Secondary
ST1 x x
ST2 x x
ST3 x x
ST4 x x
ST5 x
Table 5-1 – Material selection
Type 1-4 steel are used where charpy impact tests and CTOD testing is required.
Type 2 and 4 steel shall be used where loads in thickness direction occur for
thickness of 25 mm and above.
5.2.1 Chemical Properties
Where galvanising has been required the content of Silicon (Si) in the steel shall beminimum 0.15% and maximum 0.40%. The desirable content of Silicon is between
0.15% and 0.25%. Steel type 3 and 4 shall not be galvanised.
5.2.2 Bolting Material
All bolts and nuts shall be delivered and marked according to ISO 898-1 class 8.8and ISO898-2 class 8 respectively unless otherwise specified on design drawings. Allbolts and nuts shall be hexagon type with ISO metric thread.
Bolts and nuts with diameter 10 mm or more shall be hot dip galvanised according toISO 1461 class E and ISO 1459.
Bolts with diameter less than 10 mm shall be made of stainless steel, ISO 3506
grade A4-70, unless otherwise specified on design drawings. Where used forassembling carbon steel, insulation washers to be used.
For bolting material used below LAT +4 m, a waxy rust proofing compound shall beapplied. Bolts and nuts for sub-sea installation (below LAT - 2 m) shall be PTFE(Teflon) coated.
Washers shall be according to ISO 7090 quality class HV 200. The diameter ofwasher holes to be 1 mm greater than bolt size for bolts up to 18 mm and 1.5 mm
for larger bolts. Hardened washers must be used for friction grip bolts.
Bolt, nuts and washers shall be delivered with 2.2 certificates according to EN 10204.
For assembling stainless steel parts, only stainless steel bolts shall be used.
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Split pins materials shall be stainless steel, ISO 3506 grade A4-70.
5.2.3 Internal Soundness
For internal soundness, requirements stipulated in EN 10025-X option 6, 7 and 8shall apply.
5.3 Structural Categories
Table 5-2 Structural Classification – typical applications
Structural category for Topside Structures
Special Primary Secondary
All Pad-eyes/lifting trunnion Supports for main cables& Hang-off's
Ladders
Main tubular columns Deck beams in grid lines HandrailsCrane pedestal Bracing members Stairs
Support structure for
helideck
Sea-fastening Cable ladder supports
(minor cables)
Support beams/structure for
main transformer
Deck plates GratingSecondary deck beams Supports for minor
equipment (e.g.antennas & satellite
discs)
Nodes in main tubular
Cones in main tubular
Pipe supports
Structural category for Sub-structures (Jacket)
Special Primary Secondary
Pad-eyes/lifting trunnion Mudmat Ladders
Jacket legs and braces J-tubes Handrails
Piles and pile sleeves Caissons Stairs
Boat landing (integrated) Boat landing Grating
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5.3.1 Material Certificates and Markings
Steel materials shall be delivered with inspection certificates according to EN 10204
Structural category: Material Certificate:
Special 3.2
Primary 3.1
Secondary 2.2
Table 5-3 Material certificates according to EN 10204
Where traceability is required all steel material shall be marked according to relevantstandards listed in appendix 1.
If traceability of a material is not required the material shall as minimum be marked
with material grade.Material that cannot be identified as outlined above shall be rejected.
5.4 Fabrication of Welded Structural Members
Welded tubulars shall be fabricated in accordance with API 2B. Mechanical tests for
tubulars must be carried out in the finished configuration.
Welded profiles (sections) shall be in accordance with the requirements stipulated in
appendix 1.
5.5
Standard Tubulars and Sections
Seamless tubulars shall be manufactured in accordance with API 5L unless otherwisespecified. Seamless tubulars shall be inspected in accordance with SR4.
Rolled profiles (Sections) shall be in accordance with the requirements stipulated in
appendix 1.
5.6 Stairs, Handrails and Grating for Topside
See standard drawings ref. appendix 2, 3, 4 and 5.
5.7 Stairs and grating materials for Sub-structure
Materials for grating and steps for stairs shall be GRP. Grating shall be as MouldedGrating 50x50", with anti-slip surface.
Stair treads to be as Moulded Grating Steps of a recognized industrial standard,
subject for Employer approval.
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Min 4 pcs fixations for the GRP grating is required per square meter and not lessthan 3 for each grating piece. The fasteners shall be of stainless steel AISI 316
quality.
Grating fasteners shall not be installed onto closed sections (e.g RHS e.t.c.), I.e. nopenetration of closed sections allowed.
5.8 Platform Doors.
A door schedule shall be developed as part of the design and construction. It shall be
continuously updated throughout the design and construction phase, until allrequired information is specified prior to procurement.
All external and internal doors shall be designed and fabricated in accordance with
NORSOK C-002 with respect to: Materials, fire rating and hardware.
All doors on the substation shall be of stainless steel AISI 316L with a suitablepainted surface after supplier's recommendation.
Gutter shall be installed above all external doors - made of suitable angel bar,welded to wall plate. Slope 1:100 to both sides from middle of gutter.
6. Structural steel dimensions
6.1 Tubular dimensions and tolerances
Tubulars are to fulfil the following dimensional tolerances:
OD < 406 mm tolerances according to API 5L OD 406 mm tolerances according to API 2B
As a supplementary requirement the minimum wall thickness must be as specified,i.e. no negative tolerance allowed.
All tubulars shall meet the straightness requirements for API-2B.
Out-of-roundness shall be limited to the lesser of:
OD(max.) - OD(min.) 1% of Dnom
OD(max.) - OD(min.) max{6 mm, (t mm)/10}
Additionally, the local out-of-roundness shall be measured using a 20 gauge. This
shall not depart from the theoretical shape by more than 10% of wall thickness.
6.2 Sections - dimensions and tolerances
Mechanical tests for profiles must be carried out in the finished configuration.
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Profiles shall meet the dimensional tolerance requirements of applicable standard asper Appendix 1, except for length tolerance, which shall be in accordance with EN
ISO 13920. Maximum straightness deviation shall not exceed 1/1000 of the lengthand maximum 10 mm for lengths greater than 10 m.
6.3 Steel plates
Mechanical tests for steel plates must be carried out in the finished configuration.
Steel plates shall meet the dimensional tolerance requirements of EN 10225 and EN10025.
6.4 Rectangular/square hollow sections
Mechanical tests for rectangular/square hollow sections must be carried out in thefinished configuration.Rectangular/square hollow sections shall meet the dimensional tolerance
requirements of EN 10225 and EN 10025.For primary steel only seamless hollow sections are allowed.
7.
Structural fabrication
All fabrication shall be carried out in accordance with agreed procedures, approved
design drawings and shall comply with applicable codes and standards listed in saidETS.
7.1
Storage and handling of steel materials
When materials are received contractor shall inspect them in order to ensure that:
a) Marking of materials complies with the documentation
b) Documentation complies with the latest revision of the relevant specification
c) Materials are not damaged during transportation
The inspection shall be documented in a materials receiving inspection report
Storage of material or subassemblies shall be above ground level, ensuring that it is
kept free of dirt, grease, paint and other alien materials. All materials and
subassemblies shall be handled and stored in a way that will ensure that the materialis not damaged.
All materials shall be traceable to the Energinet.dk contract in question.
7.1.1 Identification system
Before starting of fabrication contractor shall establish a numbering system to
identify each weld and structural member in order to eliminate conflicting orduplicating of identification systems.
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For structures in the structural categories Special and Primary , the numberingsystem shall ensure traceability for all welds and materials during all stages of
fabrication and in the as-built documentation.
For structures in the structural category Secondary , the numbering system shall
ensure traceability during all stages of fabrication.
7.1.2 Alignment
Wherever practical, clamps, magnets holding devices or other setting-up fixturesshall be used in assembling parts of the structures in order to minimise tack welding
in the weld groove.
If fit-up clamps cannot be used spacer strips shall be used in order to ensure the
specified root gap prior to tack welding.
7.2 Structural sections and plates
All welds shall be continuous (closed welds). A minimum of 4 mm throat thicknessseal weld shall be applied where structural welds are not required.
Beam sections with identical cross sections may be spliced. Minimum distancebetween 2 splices shall be 1200 mm.
The splices cannot be located within the first 1/8 or the middle 1/4 of a section
7.3 Scaffolding hooks
Unless otherwise noted on design drawings, scaffolding hooks are to be installed
below all decks in a 2m x 2m grid.
7.4 Bolted connections
Procedures for the bolt tightening shall be prepared prior to the work and records of
the tensioning shall be maintained during the work.If bolt pre-stressing is required according to the design drawings hydraulic pulling
pre-stress tool shall be used unless otherwise agreed with Energinet.dk. Calibrationof pre-stressing tools shall be documented.
Bolt heads and nuts shall rest squarely within 3 against the base material, and bolts
shall be of lengths that will extent entirely through and up to a maximum of 6 mm
beyond the nuts.
No welding is allowed on bolt items.
Counter nuts shall secure all nuts unless otherwise noted.
Washers shall be used at both bolt head and nut except when tensioning equipmentis used. Spring washers are not allowed in structural members.The galvanized surface for the fasteners must remain intact after tensioning.
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All holes shall be drilled and reamed as necessary prior to application of protectivecoating. Outside burrs resulting from drilling or reaming operations shall be removed
with a tool making a 2 mm bevel.
Grease shall always be applied when using torque-tensioning technique. The grease
shall be of the non-corrosive type and must not contain Sulphur (e.g. MoS2).
7.4.1 Bolts in shear and tension connections
Bolts in structural members from M12 mm and up shall be pre-stressed to 50% ofyield strength unless otherwise specified.
7.4.2 Friction grip connections
Bolts shall be pre-stressed and documented as specified on drawings.
Enlarging of holes for high stress bolts shall be carried out by reaming only. Holesshall be clean-cut without torn or ragged edges. Outside burrs resulting from drillingor reaming operations shall be removed with a tool making a 2 mm bevel.
7.5
Helidecks
The main supporting steel structure for a helideck on the topside structure is coveredby this standard.
The lattice structure typically integrated under the helidecks shall be made of
seawater resistant aluminium unless otherwise stated. For classification, reference is
made to ‘Offshore Standard, Helicopter Decks DNV-OS-E401.
The helidecks shall be designed and marked to comply with ‘Statens Luftfartsvæsen’regulation BL 3-5.
Walkways, railings and stairs from the decks to the topside shall be included and arealso to be designed in seawater-resistant aluminium, if assembled with aluminiumhelideck.
7.6 Lifting fittings
Lifting fittings are defined as lifting lugs, lifting trunnion and pad eyes.
For lifting fittings, the additional requirements presented in this section must befulfilled.
7.6.1 Definition
Lifting fitting loads are defined as follows:
Low load: Max 10 tonnes unit load
Normal load: Max 50 tonnes unit load
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High load: Above 50 tonnes unit load
Unit load is the total current weight of the structure to be lifted.
7.6.2 Materials and Fabrication
All materials for lifting fittings shall be of steel type 3 special steel.
Welding of lifting fittings shall be of full penetration type welds unless noted
otherwise on the design drawings.
All plates for lifting fittings shall be examined 100% according to EN 10160 Class S1
Pinholes in pad eyes shall be machined. If cheek plates are fitted the machining of
the hole shall be carried out after welding of the cheek plates.
Full dimensional and orientation checks of all lifting fittings shall be made upon
completion. Complete non-destructive re-testing by means of MT and UT shall becarried out on all lifting fittings after each lift or when load has been applied.
The lifting fittings shall be completed with a topcoat RAL 1004 (yellow) and markedwith SWL in black letters.
7.6.3
Additional RequirementsThe following additional requirements apply for “high load” and “normal load” lifting
fittings:
In pad eye plates, the final rolling direction shall be indicated by hard stamping
Lifting direction shall be in the final rolling direction
For “high load” the following further requirements apply:
Full mechanical and chemical re-test shall be performed
Charpy impact testing shall be performed transverse to the final rolling direction Tensile test pieces shall be tested transverse to the final rolling direction Where “high load” lifting fittings are welded directly onto a structure, the
structural members shall have documented through thickness properties (i.e.type 2 or 4 steel). Otherwise, the pad eye shall be sliced into the structure
For “normal load” and “low load” the following additional requirements apply:
A chemical re-test shall be performed to document the traceability between thematerial and the original certificate.
For lifting fittings in “low load” , the chemical re-test may be avoided if an
additional material factor of 1.5 is used in the design.
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7.7 Finishing of structural steel
All temporary attachments for scaffolding, temporary bracing etc. shall be removedby cutting not closer than 3 mm to the structure and then ground flushed with thesurface. Subsequently, 100% MT shall be performed. Minor surface defects on
primary steel shall be ground to sound metal, 100% magnetic particle inspected,
weld repaired, if necessary, and magnetic particle re-inspected.
7.8 Fabrication of non-structural steel and temporary attachments
When welding non-structural and temporary attachments to primary structural
components a minimum clearance of 200 mm between any attachments weld toeand any structural component weld toe shall be kept.
All temporary welds shall require a minimum of two weld passes. The last pass (es)shall be deposited against the temporary part.
7.8.1 Temporary cut-outs
When temporary cut-outs are necessary they shall be prepared with the same careas for permanent cut-outs including carefully rounded corners.
7.8.2 Rat holes (Weld access hole)
Rat holes shall only be used where absolutely required and they shall then have aradius of 30 mm. The welds shall be continued through the rat hole.
Rat holes shall be sealed with closure plates fillet welded to the structure after
completion of NDE on the main steel.
7.9 Fabrication dimension tolerances
The fabrication dimensional tolerances for erection of constructions shall be inaccordance with DNV-OS-C401.
In addition to the requirements in DNV-OS-C401, the tolerances for linear andangular dimensions and straightness shall be as stated in the following tables.
The fabrication tolerances for design dimensions for sections at interface points I.e.stabbing guides, top of jacket e.c.t shall be within table 7-1, but never exceed 10mm
regardless of the design dimension.
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7.9.1 Tolerances for linear dimensions
Tolerances for linear dimensions shall be in accordance with EN ISO 13920, Class B
and C.
Range of nominal length in mm
Tolerance Class
(Structural
Category)
<
3 0
< 1 2 0
< 4 0 0
< 1 0 0 0
< 2 0 0 0
< 4 0 0 0
< 8 0 0 0
< 1 2 0 0 0
< 1 6 0 0 0
≤ 2 0 0 0 0
>
2 0 0 0 0
Tolerances in mm
B (Special) ±1 ±2 ±2 ±3 ±4 ±6 ±8 ±10 ±12 ±14 ±16
B (Primary) ±1 ±2 ±2 ±3 ±4 ±6 ±8 ±10 ±12 ±14 ±16
C (Secondary) ±1 ±3 ±4 ±6 ±8 ±11 ±14 ±18 ±21 ±24 ±27
Table 7-1 – Tolerances for linear dimensions
7.9.2 Tolerances for angular dimensions
Tolerances for angular dimensions shall be in accordance with EN ISO 13920, Class B
and C. The length of the shorter angle leg as specified in the following table shall be
used to determine which tolerances are to apply.
Range of nominal sizes l in mm (l=length of shorter leg)
Tolerance Class
(StructuralCategory)
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Range of nominal length in mm
Tolerance Class
(Structural
Category) < 1
2 0
< 4 0 0
< 1 0 0 0
< 2 0 0 0
< 4 0 0 0
< 8 0 0 0
< 1 2 0 0 0
< 1 6 0 0 0
< 2 0 0 0 0
< 2 0 0 0 0
Tolerances in mm
E (Special) ±0,5 ±1 ±1,5 ±2 ±3 ±4 ±5 ±6 ±7 ±8
E (Primary) ±0,5 ±1 ±1,5 ±2 ±3 ±4 ±5 ±6 ±7 ±8
F (Secondary) ±1 ±1,5 ±3 ±4,5 ±6 ±8 ±10 ±12 ±14 ±16
Table 7-3 – Tolerances for straightness, flatness and parallelism
The dimensions given in the drawings are applicable at a temperature of +10C.
Corrections must be performed if the manufacturing temperature differs from this,by more than 10 C.
Contractor shall submit construction drawings marked up to as-built status and
indicate as-built interface dimensions, which could affect offshore operations.
7.9.4 Section ends
The ends of sections cut perpendicular to the longitudinal axis shall be perpendicularto the axis with a maximum deviation of 3 mm, unless otherwise indicated on the
drawings.
7.9.5 Location of seams
Minimum distance between circumferential seams in tubular shall be 1200 mmunless shown otherwise on the drawings. Length of node stubs shall not be less than
the outside diameter or 610 mm whichever is the strictest.
Circumferential seams shall be avoided within node stubs.
Longitudinal seams shall preferably be 180 degrees offset wherever practical and
shall not be less than 15 degrees offset.
The longitudinal seams on node chord cans shall be located at a minimum radial
distance of 75 mm from the edge of any brace to chord welds.
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7.9.6 High-low
High-low, defined as a condition where tubular surfaces are misaligned, can be
accepted provided the misalignment does not exceed 3 mm for single sided weldingand 6 mm for double sided welding. The root of adjacent tubular joints shall be
completely tied-in (bonded) by weld metal and smooth transition shall be assured.
The maximum acceptable misalignment as specified in EN ISO 5817.
7.9.7 Plates and grating
Grating shall be flat and without visible warping. Maximum allowable warping is 2mm. Slope of plates and grating shall be maximum ±6 mm/3 m.
7.9.8 Landings and stairways
Horizontal and vertical location of landings and stairways shall not deviate fromtheoretical measures on design drawings with more than 10 mm.
7.9.9 Interface tolerance
Interface checks between Topside and Sub-structure shall be subject for detailedreview and scrutiny by the Contractor.
The result of said review shall be subject for approval by Energinet.dk.
7.9.10 Markings Sub-structure.
Water level figures shall be painted on the jacket legs, oriented 450 with respect tothe gridlines.
The water level marking shall consist of a circumferential marking line at every
meter, start and end elevation to be agreed. The lines shall be black on yellowbackground. Line width shall be 100 mm for El (+) 0.000, and 50 mm for all other
elevations.
The figures shall be min 500 mm high, painted black on yellow background.
The jacket leg id number shall be painted on 3 locations around the circumferencewith 400 mm high identification letters at agreed elevation. The id's letter/figuresshall be black on rectangular white background.
8. Welding
The welding workshop shall have a quality management system in accordance with
ISO 9001, ISO 3834 series or equivalent standard.
An organisation chart, which as a minimum shall include the names of the
responsible manager, quality responsible, welding and NDE coordinator, and NDElevel III, shall be available.
8.1 Welding processes
Welding may be performed with the following processes unless otherwise specified:
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Metal-arc welding with covered electrode
Self-shielded tubular-cored arc welding Submerged arc welding
Metal inert gas welding (MIG)
Metal active gas welding (MAG) Tubular-cored Metal arc welding Tungsten inert gas arc welding (TIG)
Plasma arc welding
Other welding processes shall be agreed with Energinet.dk prior to fabrication.
8.2
Qualifications of welders and welding operators
8.2.1 Welding coordinator
The workshop shall have one welding coordinator whereby welding personnel can besupplied with the necessary procedure specifications and work instructions to ensure
that the work is correctly executed and managed.
The welding coordinator shall be certified European Welding Engineer (EWE) or
similar.
8.2.2 Welders and operators
All welders and operators shall be experienced and qualified in the workshop in
accordance with the requirements of EN 287 series, ISO 9606, ASME IX orANSI/AWS D1.1 for welders and EN 1418 for operators or equivalent standardsapproved by Energinet.dk.
The welder performance qualification test shall be carried out in accordance with a
qualified welding procedure specification (WPS).
8.2.3 Identification of welder or welding operator
Welder Performance Qualification (WPQ) sheets with photograph shall be used fordocumentation purpose.
Each qualified welder or welding operator shall be assigned a symbol, which alwaysshall be visible during welding. The welder or welding operator shall mark his welds
with his symbol. Welder's symbol shall be stated in NDE-reports and as-builtdocumentation for high and normal safety class structure.
8.2.4 Welder's or operator's record
A record shall be kept of the welder’s or welding operator’s symbols and be availableat all times.
A record of the welders or welding operators work performed during the last 12
months shall be available to Energinet.dk at all times.
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8.2.5 Test for branch connections
Tests of welders for branch connections (Y-joints) are given below for the structuralcategories Special and Primary .
‘Y’ joint welder's qualification shall be required for branch connections (Y and K
connections between tubulars or tubulars welded to plates, branch outside diameterabove 150 mm) in addition to the welding test piece positions either PC and PF or to
H-L045/G6 qualification.
The test weld is a Y-joint between a vertical plate and a tube (branch) with a min.diameter of 200 mm and with an inclination of 35. Groove geometry shall be as
specified in the relevant welding procedure qualification record. The plate thickness
shall be at least 15 mm and shall have a minimum length and width equal to two
times branch outside diameter. The thickness of the branch shall be at least 15 mm.
Free end of the branch shall be oriented downwards in relation to vertical and becovered by a temporary plate during welding.
The welding parameters shall be in accordance with a qualified welding procedure.No back welding is permitted.
All test welds shall be 100% ultrasonic tested in accordance with section 8.0
From the test weld three macro sections taken from 6 o’clock, 9 o’clock and 12
o’clock shall be made.
Each macro section shall be examined and found to be acceptable to ASME codesection VIII.
8.3 Welding procedures
8.3.1 General
Welding Procedure Qualification Records (WPQR's) shall reflect the production andshall be performed in accordance with EN ISO 15614-1 or ASME IX, unless otherwise
stated in this section.WPS (Welding Procedure Specification) shall be prepared in accordance with EN-288-1, AWS D1.1 or an equivalent standard approved by Energinet.dk
WPS's inclusive copy of reference WPQR shall be issued to Energinet.dk for approvalprior to commencement of welding.
The material used in the WPQR shall be made on project materials only.Already established, sufficiently tested and documented procedures may however,
be acceptable, if approved by Energinet.dk prior commencement of production.
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Test body shall be acceptable to Energinet.dk. Test bodies will be approved ifaccredited by national authorities according to EN 45004 for certification of welding
procedures according to EN ISO 15614-1 series or ASME IX.
The validity of a qualified welding procedure is restricted to the workshop specifying
the procedure and performing the procedure welding. Workshops or workshopbranches under the same technical management and working in accordance with thesame QA-programme and procedures are considered as one workshop.
For welding of structural category Secondary only approved WPS’ are required.
8.3.2 Specific requirements
The degree of cold deformation of special and primary structural elements shall be
less than 5%. If the deformation exceeds 5%, either heat treatment or strain ageing
tests shall be carried out according to agreed procedure.
The carbon equivalent (CE) of the production material shall not exceed that of the
steel used for the WPQR by more than 0.03%.
Deviations from the specific requirements shall require a new welding proceduretest.
8.3.3 Test of the procedure welds
Examinations shall be performed not earlier than 48 hours after completion of theweld.
CTOD testing (Fracture mechanics testing) shall be performed in accordance with therequirements stipulated in DNV-OS-C101.
CTOD test shall be carried out according to BS 7448 Part 2 (with detailedrequirements as given in DNV-OS-C401).
Hydrogen removal treatment is not allowed without prior approval fromEnerginet.dk.
CTOD results shall be calculated using appropriate values of yield stresses.
Charpy-V Impact test:
The following minimum values shall apply:
Steel type Steel type 1 - 4 Steel type 5
Charpy-V impactvalues (J)
50 27
Temperature (oC) -40 -20
Table 8-1 Minimum average Charpy-V notch impact test value
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8.4
Production welding
8.4.1
Welding sequencesContractor shall develop erection sequences, which shall include welding sequencesto control fabrication tolerances within the specified limits and prevent the build-up
of excessive internal stresses in the structure.
8.4.2 Weld preparation
Contractor shall establish shielding to protect each welding site from rain, snow andwind. No welding shall be carried out when the surface is damp, wet or icy'.
Preparation and welding of materials shall be in accordance with the qualifiedwelding procedures.
Welds shall be made from both sides whenever possible. Single sided butt weldsshown on the design drawings may be executed from the other side to suit
fabrication.
8.4.3 Weld execution
Workmanship
Clean, sound metal shall be provided as a base for weld metal deposition; this maynecessitate grinding or gouging followed by grinding at a depth of min. 2 mm.
Double-sided welds shall be back-gouged and ground or ground to sound metal
before the second side is welded. The resulting excavation shall have a profilesuitable for welding.
Each run of weld metal shall be thoroughly cleaned of flux, spatter and slag beforedepositing the next weld run. If necessary, crater cracks shall be removed prior to
deposition the next weld run.
Arc strikes
Arc strikes outside the welding groove are not permitted. Repair will be grinding inaccordance with section 7.7. Suitable NDE methods shall be used to search forcracks.
Tack welds
Tack welds shall be of a minimum length of four times the base metal thickness or
100 mm, which is lesser, and carried out according to a qualified welding procedure.
Tack welds shall have adequate cross section to prevent cracking.
Tack welds that form part of the completed weld shall be cleansed, crack detectedand completely fused with the root run.
Cracked tack welds shall be completely removed by grinding and shall not beincorporated into the finished weld. After removal, the parent material shall be
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magnetic particle or liquid penetrant examined to ensure that crack propagationfrom the tack weld into the parent material has not occurred.
Arc/air gouging
All arc/air-gouged surfaces shall be dressed to bright clean metal by grinding at an
additional depth of min. 2 mm. The gouged/grounded profile shall be suitable forwelding with the applicable process.Specific care shall be taken that the arc is not struck before full airflow is
established.
Energinet.dk shall approve the procedure prior to gouging.
Weld interruption
Welding shall not be discontinued before 25% or 3 passes of the weld thickness is
complete, whichever is more stringent. At this stage the weld profile should beconcave particularly at the weld material/parent plate interface.
Branch connections
Qualified T-joint welders shall be used for the first 25% or 3 passes of the weld,whichever is more stringent. For the other passes welders qualified in the H-L045position may by used.
Joint preparation and cleaningWire brushing and grinding of materials shall be performed using silicon carbide
grinding wheels and steel wire brushes, which have not been used previously on
another type of material.
BackingPermanent backing is not permitted unless accepted by Energinet.dk prior to
fabrication.
8.4.4 Pre-heating
Pre-heating shall be carried out by electrical resistance, induction equipment or by
use of gas burners specifically made and shaped for this type of operation. Cutting
torches are not allowed for pre-heating.
The minimum pre-heat temperature shall be the higher of the following:
a) The temperature specified in the relevant approved welding procedure.
b)
Work pieces shall be heated to ensure a minimum temperature of 25 C and
dryness.
c)
The minimum temperature shall be calculated according to EN 1011
The pre-heat temperature shall be established for a distance of at least 75 mm on
either side of the weld and through the wall thickness prior to welding. Pre-heating
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shall be maintained over the full length of the joint or min. 1 m ahead of the arc andthroughout the whole welding operation.
The temperature measurement for pre-heating shall be thermocouples or
temperature-indicating crayons.
8.4.5 Inter-pass temperature
The minimum inter-pass temperature shall be at least equal to the pre-heat
temperature and shall not exceed 250 C.
8.4.6 Post weld heat treatment (PWHT)
Post weld heat treatment (PWHT) shall always be performed according to the sameapproved WPQR as the welding has been based on.
Due to requirements from the design code PWHT shall be performed with electricresistance, induction equipment or in a fixed furnace, when applicable. The
temperature shall be monitored by means of thermocouples. Sufficient amount ofthermocouples shall be used to cover the area being PWHT adequately.
PWHT shall be determined in accordance with DNV-OS-C401.
The weld shall be PWHT and the surrounding area shall be covered with insulationmaterial covering minimum 500 mm on each side of the weld. The insulationmaterial shall not be removed before the temperature is below 250 C. For tubular
the open ends shall be covered to avoid draught inside the tubular during the heat
treatment.
PWHT temperature/time charts shall be clearly identified and retained. Theinformation shall be accurately transferred from the charts to thermal history graphs.
8.4.7 Weld repairs
All corrective work consisting of removal of defects and deposition of repair weldsshall be in accordance with the qualified repair welding procedure. Alternatively, thedeposition of repair weld shall be in accordance with a welding procedure qualified
for the original weld.
Removal of defective areas shall be by machining, grinding, chipping or arc/airgouging followed by grinding. The resulting excavation shall be clean, free from scaleand have a contour to permit ease in repair welding. MT or PT shall assure defect
removal.
The mechanical properties of repair weld shall satisfy the minimum specifiedproperties of the steel in question.
Repairs and modifications shall be identified and documented.
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Second weld repair requires Energinet.dk approval.Frequent repairs shall result in increased NDE according to DNV-OS-C401, Section 3
– B400.
8.4.8 Production testing
Energinet.dk reserves the right to select test welds for production tests directly from
the production welds.
The testing shall be performed to the requirements of this ETS, however; CTOD
testing is not required. If a full test procedure cannot be performed because of lackof material (e.g. small diameter pipes, etc.), only the hardness tests and the
technically possible amount of Charpy tests shall be performed with the belowpriority:
1)
The notch crossing the fusion line symmetrically2)
1) + 2 mm3)
1) + 5 mm
4)
The notch on the weld centre line
If the production test is not fulfilling the requirements the cause of failing shall be
established immediately and brought to the attention of Energinet.dk
9. Non-destructive examination
This section specifies the requirements to NDE for the structural welds performed onthe fabrication site.
Inspection categories are in accordance with the requirements stipulated in DNV-OS-
C101.
Non-destructive examination shall be carried out according to DNV-OS-C401,
Following methods are applicable:
Visual examination (VT)
Magnetic particle examination (MT)
Liquid penetrant examination (PT)
Ultrasonic examination (UT)
Radiographic examination (RT)
Eddy current (ET)
9.1 Extent of examinations
The extent of NDE shall be based on type and level of design stresses and on the
importance of the connection in question.
The welds shall be assigned inspection categories equal to the highest structuralcategory of the two components.
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NDE shall be carried out to an extent not less than required in DNV-OS-C401.
9.2 NDE Qualifications
9.2.1 Examination organisation
The organisation performing NDE shall be an independent inspection unit accredited
according to EN ISO 17025 or equivalent.
9.2.2 Examination personnel
All personnel shall be certified in accordance with EN 473 or equivalent and the unitshall as a minimum include one certified level III inspector, who shall have theoverall technical responsibility for the NDE activities, i.e. approval of procedures,
equipment, technique etc.The personnel performing NDE shall, as a minimum be certified as level II, or work
under direct supervision of a certified level II person.
9.2.3 Procedures
All NDE shall be performed in accordance with agreed written procedures, which
have been approved by the responsible level 3 inspector and in accordance with therequirements of DNV-OS-C401 standard.
9.3 Execution of NDE
All plates, tubulars and profiles in the structural categories Special and Primary shallbe checked by NDE according to one or more of the methods specified in DNV-OS-
C401.
Radiographic examination may be replaced by ultrasonic examination and vice versa,
when methodologically justifiable and in agreement with the Energinet.dk.
9.4
NDE procedure and acceptance criteria.
The acceptance criteria level shall, for special structures comply with ISO 5817 levelB. Welds of category primary/secondary shall comply with ISO 5817 level C.
9.4.1 Visual (VT) procedure and acceptance criteria
100% VT shall be performed on all welds.
EN 970 or AWS D1.1 shall be used as examination technique for visually examinationof weld preparation and finished welds.
Acceptance criteria for visual and magnetic testing shall be according to ISO 5817quality level B or C with the additional requirement that pinholes, slag stripes, poresetc. shall not be accepted for welds, which shall be coated.
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9.4.2 Magnetic particle (MT) procedure and acceptance criteria
Examination technique shall be in accordance with EN 1290 or ASTM E 709.
Examination shall be performed for indications in any directions. AC electromagneticyoke shall be used.
Detection media shall be of liquid type, fluorescent or black. If black suspended
power is used, the examination surface shall be covered by a thin layer of contrast
paint.
Acceptance level shall be as per EN ISO 23278 2x or ISO 5817 level B or C
9.4.3 Radiographic testing (RT) procedure and acceptance criteria
Examination technique shall be in accordance with EN 1435 class B.
Acceptance level: EN 12517 level 1.
9.4.4 Ultrasonic testing (UT) acceptance criteria
The examination shall be performed and evaluated as follows:
Examination level: EN 1714 level B, annex A.
Acceptance level: EN 1712 level 2.
9.4.5 Liquid Penetrant testing (LP) acceptance criteria
Examination technique shall be in accordance with EN 571-1.
Acceptance level: EN 1291 2X.
9.5 Execution of NDE, structural fabrication
9.5.1 General
All NDE shall be performed after final post weld heat treatment, if applicable.
NDE examination shall, at the earliest, be commenced 48 hours after weldingcompletion. Alternatively, the welding can be heated to 200 °C and held at that
temperature for two (2) hours. NDE can then be executed after cooling to thetemperature required for performance of the examination.
This procedure is subject to Energinet.dk approval.
For welds in secondary structure (handrails, kick plates ladders e.t.c) not welded to
special or primary structures, NDE can be performed after cooling to the temperaturerequired for performance of the examination required.
All Plates which are subjected to tensile stresses in the thickness direction in way ofcross joints, etc. shall be ultrasonically tested after welding into the structure, to
make sure that lamellar tearing has not taken place. If steel with improved through
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thickness properties (steel type 2 and 4) has been adopted, this test may be reducedto spot-check only.
Welds in hollow sections shall be 100% leak tested or 100% MPI tested.
9.5.2 Sequence of examination
Visual examination shall always be performed prior to other examinations. Whenexaminations for detection of internal as well as external defects are required for thesame weld the examination for external defects shall be performed prior to the
examination for internal defects.
9.5.3 Surface conditions
The surface and the adjacent area to be examined shall be clean and free of all dirt,grease, paint, spatter, heavy oxidation etc. that may interfere with the examination.
To assure the examination and interpretation of results the weld surface shall beprepared by grinding, if necessary.
NDE shall be performed prior to application of linings and coatings.
9.5.4 Random examination
Where random examination (spot check) is required a complete examination of the
specified percentage of the welds in the lot shall take place.
The selection of welds to be examined may be at the discretion of the inspector fromEnerginet.dk. Where practical, the selection shall ensure that the work product of
each welder or welding operator performing the welding is included.
9.5.5 Extent of examination in case of unacceptable welds
All unacceptable indications shall be removed. Where weld repair is required, the
repair area shall be re-examined for external defects prior to welding including 100mm on either side. Weld repairs (or replaced welds) shall be examined with thesame method as the original weld.
Where random examination reveals unacceptable indications the following actions
shall be taken:
a)
Two additional welds by the same welder or welding operator shall beexamined with the same examination method.
b) If the results of the examination according to a) are acceptable the defective
weld shall be repaired and re-examined and all welds in the lot areconsidered acceptable.
c) If the results of the examination according to a) are unacceptable two furtherwelds by the same welder or welding operator shall be examined for each
defective weld.
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d)
If the results of the examination according to c) are acceptable, the defective
welds shall be repaired and re-examined, and all welds in the lot areconsidered acceptable.
e) If the results of the examination according to c) are unacceptable, all weldswelded by the same welder or welding operator shall be either:
- Examined 100%. Repaired and re-examined as applicable.
10. Coating
The minimum requirements are given in Energinet.dk technical standard “Protective
Coating of Steel – ETS-25”
11. As-built documentation
As-built documentation shall be compiled and submitted by the contractor to
Energinet.dk after execution of the work. The as-built documentation shall include,but not be limited to the following:
Documentation index
Third part inspection release note (If applicable) Manufactures declaration of conformity (certificate of conformity)
List of as-built drawings As-built traceability drawings. The traceability shall cover all welding, materials
and NDE of the structure
Dimension reports, when applicable
NDE reports
NDE personnel certificates
List of approved WPS
List of approved welders
Weight reports, when applicable
Approved deviation reports and technical site queries List of material certificates
Material certificates Coating documentation
The as-built documentation shall further be compiled in accordance with EDS - 02.
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11.1
Deliverables
Contractor shall deliver the following set of documentation to Energinet.dk:
Shop and design drawings in AutoCAD and PDF format, as per EDS-50-01.
The electronic documentation shall be prepared as pdf files with bookmarks.
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12. Appendix
Appendix 1A. Steel Types and Quality for Topside structures
SteelType
Material Type Material Dim Standard Steel Quality Description
ST1 Plates
Plates
Sections
Welded hollow sections
Seamless hollow sections
T ≤ 50 mm
T > 50 mm
All
All
All
EN 10025
EN 10025
EN 10025
EN 10219
EN 10210
S355J2
S355NL
S355J2
S355J2H
S355J2H
Primary Steel
ST2 Plates
PlatesSections
Welded hollow sections
Seamless hollow sections
T ≤ 50 mm
T > 50 mmAll
All
All
EN 10025
EN 10025EN 10025
EN 10219
EN 10210
S355J2
S355NLS355J2
S355J2H
S355J2H
Primary Steel withrequirements for improved
deformation propertiesperpendicular to the surfaceof the product , EN 10164Quality Class Z35
ST3 Plates
Plates
Sections
Welded hollow sections
Seamless hollow sections
T ≤ 50 mm
T > 50 mm
All
All
All
EN 10025
EN 10025
EN 10025
EN 10219
EN 10210
S420N
S420NL
S420N
S420N
S420N
Primary Steel
ST4PlatesPlates
Sections
Welded hollow sections
Seamless hollow sections
T ≤ 50 mm T > 50 mm
All
All
All
EN 10025EN 10025
EN 10025
EN 10219
EN 10210
S420NS420NL
S420N
S420N
S420N
Primary Steel withrequirements for improveddeformation propertiesperpendicular to the surfaceof the product , EN 10164Quality Class Z35
ST3-S Plates All EN 10225
EN 10225
S420G1+Q
S420G1+M
Special Steel:
ST4-S Plates All EN 10225
EN 10225
S420G1+Q
S420G1+M
Special Steel withrequirements for improveddeformation propertiesperpendicular to the surface
of the product , EN 10164Quality Class Z35
ST5 Plates
Plates
Sections
Welded hollow sections
Seamless hollow sections
Bulb flats
All EN 10025
EN 10025
EN 10025
EN 10219
EN 10210
EN 10067
S235
S235
S235
S235
S235
S235
Secondary Steel.
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Appendix 1B Steel Types and Quality for Sub-structure (Jacket)
Steel
Type
Standard Steel Quality
1 EN 10225 Plates: S355G9+N/G9+M
Sections: S355G11+N/G11+M
Welded hollow sections: S355G13+N
Seamless hollow sections: S355G14+Q/G14+N
2 EN 10225 Steel with requirements for improved deformation propertiesperpendicular to the surface of the product , EN 10164Quality Class Z35
Plates: S355G9+N/G9+M+Option 13
Sections: S355G11+N/G11+M+Option 13Welded hollow sections: S355G13+N+Option 13
Seamless hollow sections: S355G14+Q/G14+N+Option 13
3 EN 10225 Plates: S420G1+Q/G1+M
Sections: S420G3+M
Welded hollow sections: S420G5+Q
Seamless hollow sections: S420G6+Q
4 EN 10225 Steel with requirements for improved deformation propertiesperpendicular to the surface of the product , EN 10164
Quality Class Z35Plates: S420G1+Q/G1+M+Option 13
Sections: S420G3+M+Option 13
Welded hollow sections: S420G5+Q+Option 13
Seamless hollow sections: S420G6+Q+Option 13
5 EN 10025 S235-S275
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Appendix 2
Drawing 10H 04 050 Stair - Standard drawing.
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Appendix 3
Drawing 10H 04 051 - Standard drawing, removable/fixed handrail.
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Appendix 4
Drawing 10H 05 052 -. Standard drawing, removable handrail, heavy duty
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Appendix 5
Drawing 10H4 04 053 -. Typical details, grating