TABLE OF CONTENTS - Neptune Energy · shall be in accordance with EN 10164, to meet Quality Class...

Neptune Energy Netherlands B.V.

Specification 201 rev. 13 of 24

TABLE OF CONTENTS

1.0 SCOPE .............................................................................................................................................. 4

1.1 GENERAL ........................................................................................................................................................... 4 1.2 CERTIFICATION ............................................................................................................................................... 4 1.3 QC-PLAN ........................................................................................................................................................... 4 1.4 COATING ........................................................................................................................................................... 4

2.0 MATERIALS ..................................................................................................................................... 5

2.1 GENERAL ........................................................................................................................................................... 5 2.1.1 Structural Steel ........................................................................................................................................... 5 2.1.2 Delivery ......................................................................................................................................................... 5 2.2 MATERIAL GRADES ....................................................................................................................................... 5 2.2.1 Type I - Special High Strength Steel ................................................................................................. 6 2.2.2 Type II - Primary High Strength Steel ............................................................................................... 7 2.2.3 Type III - Secondary High Strength Steel ........................................................................................ 8 2.2.4 Type IV - Mild Steel .................................................................................................................................. 8 2.3 SPECIFICATIONS FOR STEEL ...................................................................................................................... 9 2.4 MISCELLANEOUS STEEL .............................................................................................................................. 9

3.0 FABRICATION ............................................................................................................................... 11

3.1 GENERAL ......................................................................................................................................................... 11 3.1.1 Design ......................................................................................................................................................... 11 3.1.2 Drawings..................................................................................................................................................... 11 3.1.3 Marking ....................................................................................................................................................... 11 3.1.4 Sawing, shearing, flame cutting and chipping ............................................................................ 11 3.1.5 Laminations, cracks, or split ends ..................................................................................................... 12 3.1.6 Batten plates, clamps, magnets, setting-up fixtures ................................................................. 12 3.1.7 Shearing ...................................................................................................................................................... 12 3.1.8 Stud welding ............................................................................................................................................. 12 3.2 PIPE AND EQUIPMENT SUPPORTS, HOLES, CUT-OUTS, PENETRATIONS ............................. 12 3.3 EARTH LUGS ................................................................................................................................................... 12 3.4 STIFFENERS ..................................................................................................................................................... 13 3.5 SECTIONS OF PIPE ....................................................................................................................................... 13 3.6 SECTIONS OF BEAMS ................................................................................................................................. 13 3.7 MOUSE HOLES .............................................................................................................................................. 13 3.8 SURFACE PREPARATION ........................................................................................................................... 13 3.9 DECK FABRICATION .................................................................................................................................... 13

4.0 WELDING AND INSPECTION ...................................................................................................... 14

4.1 GENERAL ......................................................................................................................................................... 14 4.1.1 Procedure qualification ........................................................................................................................ 14 4.1.2 Welder qualification ............................................................................................................................... 14 4.2 INSPECTION ................................................................................................................................................... 14 4.3 REPAIRS ........................................................................................................................................................... 15

5.0 BOLTED CONNECTIONS.............................................................................................................. 16

5.1 GENERAL ......................................................................................................................................................... 16 5.2 MATERIAL ........................................................................................................................................................ 16 5.3 DESIGN AND USE......................................................................................................................................... 16 5.4 BOLT COATING ............................................................................................................................................. 17



6.0 CATHODIC PROTECTION ............................................................................................................ 18

6.1 GENERAL ......................................................................................................................................................... 18 6.2 DESIGN CRITERIA ......................................................................................................................................... 18 6.3 ANODES ........................................................................................................................................................... 18

7.0 ADDITIONS/AMENDMENTS ...................................................................................................... 19

7.1 GENERAL ......................................................................................................................................................... 19 7.2 PIPE-SECTIONS TO BE ASSEMBLED ...................................................................................................... 19 7.2.1 Material length ........................................................................................................................................ 19 7.2.2 Out-of-Roundness .................................................................................................................................. 19 7.2.3 Bevels ........................................................................................................................................................... 19 7.2.4 Straightness............................................................................................................................................... 19 7.2.5 Weld inspection ....................................................................................................................................... 19 7.2.6 Material toughness ................................................................................................................................ 19 7.3 MAIN PAD-EYES ........................................................................................................................................... 20 7.3.1 Design ......................................................................................................................................................... 20 7.3.2 Material ....................................................................................................................................................... 20 7.3.3 Fabrication ................................................................................................................................................. 20 7.3.4 Non-Destructive Testing ...................................................................................................................... 20 7.4 PENETRATIONS ............................................................................................................................................. 20

8.0 REFERENCES ................................................................................................................................. 21

ATTACHMENT 1 ........................................................................................................................................ 23

ATTACHMENT 2 ........................................................................................................................................ 24



1.0 SCOPE

1.1 GENERAL

This specification contains the technical requirements for the supply and fabrication of steel

structures. In no way this specification is intended to describe or replace the expected and

required first class workmanship for the complete fabrication of structural items, both for

strength/technical issues and for visual aspects.

1.2 CERTIFICATION

Structures and main structure parts shall be fabricated according to the rules laid down in this

specification, and are further subject to the approval of an appointed Certifying Authority. The

Certifying Authority (Bureau Veritas, Lloyd’s Register, Det Norske Veritas, American Bureau of

Shipping) will be selected and appointed by Company.

1.3 QC-PLAN

Fabrication and inspection by fabricator shall be based on a for the nature of the structure to be

fabricated suitable QC-plan. Such plan shall be prepared by Contractor and shall be subject to

approval of Company and Classifying Authorities before start of fabrication.

All attachment welding to structural parts will be considered to be per requirements laid down

in this specification.

1.4 COATING

For coating (preparation, application and galvanizing) reference is made to General

Specification 525, latest edition. Unless indicated otherwise all structural steel that is applied at

elevations from El.-4000 (LAT) up, is to be coated as per subject specification.



2.0 MATERIALS

2.1 GENERAL

Steel shall be rolled steel of commercial quality, according to NEN-EN 10225 or NEN-EN 10025,

latest edition. The notch toughness of materials will be determined by the use of the Charpy V-

notch test as given in NEN-EN 10045. All materials will be as specified in the following paragraphs

unless otherwise stated on the drawings.

2.1.1 Structural Steel

All steel provided for this platform will conform to DIN norm, Euronorm, British Standard,

American Society of Testing and Materials, or American Petroleum Institute standard

specifications, with additional considerations given herein.

In order to comply with the Dutch Mining Regulations, it is required to deliver the materials with

a certificate of a classification bureau as commissioned by "Staatstoezicht op de Mijnen". Materials

Type I, II and III shall be delivered with a 3.2 certificate in accordance with EN 10204, unless

otherwise approved by Company or/and classifying authority for the subject part of structure

before ordering. Type IV shall be delivered with a 3.1 Certificate.

2.1.2 Delivery

Except as given below, all material is to be delivered in accordance with the requirements of

Standard Specification for Delivery of Rolled Steel Plates, Shapes, Sheet Piling and Bars for

Structural Use, ASTM Designation A6.

Plate and plate for tubular (skelp) produced under DIN standards shall be delivered in accordance

with DIN 1543. Welded tubular produced under DIN standards shall be delivered in accordance

with DIN 1626 and seamless tubular produced under DIN standards shall be delivered in

accordance with DIN 1629, both with the additional requirement for straightness listed in Section

7.2.4.

Tubular produced under standards other than DIN shall conform to the dimensional tolerances of

API Specification for Fabricated Structural Steel Pipe [API specification 2B] for diameter of 24 inch

(610 mm) and over, and to the dimensional tolerances of API Specification for Line Pipe, API

specification 5L, for diameters less than 24 inch, with the additional requirement for straightness

listed in Section 7.2.4. Steel shall be new, reasonably straight and free from defects, excessive mill

scale and rust.

2.2 MATERIAL GRADES

Materials grouped into four grades of steel using the shorthand notations listed below. High

strength steel shall be designated on the drawings and in the bills of materials according to the

respective grouping listed below. However, any standard listed within the group which included

the designated Euronorm grade may be substituted. A summary is given in attachment 1 and 2

Type I - Special High Strength Steel

S355 incl. TTP and Charpy at -40°C (NEN-EN 10225 Grade S355G10+N, Grade S355G10+M,

Grade S355G12+N or Grade G15+N).

Defined in Section 2.2.1.



Type II - Primary High Strength Steel

S355 Charpy at -40°C (NEN-EN 10225 Grade S355G7+N, Grade S355G8+M, Grade

S355G11+N, Grade S355G13+N or Grade S355G14+N).


Type III - Secondary High Strength Steel

S355 Charpy at -20°C (NEN-EN 10025 Grade S355J2, NEN-EN 10225 Grade S355G1+N or

Grade S355G2+N).


Type IV - Mild Steel

S235 (NEN-EN 10025 Grade S235J0)


2.2.1 Type I - Special High Strength Steel

Special high strength steel usage:

Jacket leg joints.

Concentration of pad eyes.

Deck legs where indicated on the drawings.

Where indicated on drawing.

For tubular, shapes and plate including skelp for fabricated tubular primary high strength steel

materials shall conform to the following standards:

NEN-EN 10225 Grade S355G10+N + EN 10164-Z35

NEN-EN 10225 Grade S355G10+M + EN 10164-Z35

NEN-EN 10225 Grade S355G12+N + EN 10164-Z35 or

NEN-EN 10225 Grade S355G15+N + EN 10164-Z35

In case steel is produced according to British Standard (BS7191 Grade 355EMZ), DIN (DIN17100

Grade ST52-3N) or an other Euronorm standard (Euronorm 10025 Grade S355 J2G3), special high

strength steel shall as a minimum conform to the additional requirements here below:

The maximum carbon equivalent (where a lower value is not part of the specification under which

the steel is produced, or where the thickness or strength range of that specification is exceeded)

shall be 0.43 (ladle) calculated using the following formula:

43.01556

..

NiCuVMoCrMn

CEC

Unless waived as a requirement on written authorization of the Company's Representative, tensile

tests in the thickness direction shall be carried out in the final heat treatment condition. Testing

shall be in accordance with EN 10164, to meet Quality Class Z35. The through thickness tensile

strength shall be at least 80 percent of the minimum specified tensile strength. Special high

strength steel shall be ultrasonically inspected in accordance with EN 10160 class S1/E2

Charpy V notch test temperature - 40°C for all plate thickness (min av. 27 Joule, min. ind. 21 Joule).



Hot rolling of tubular has to be done in accordance with DIN 1626, page 3. A mechanical re-test

of the base material shall be carried out as well to prove that material has original values.

Where special high strength steel is specifically indicated on drawings as “Type I+TMCP” the

ThermoMechanically Controlled rolling Process shall be applied. This steel shall comply to EN

10225 S355G10+M +EN 10164-Z35+US. TTP and US testing shall be in accordance with Type I

steel.

2.2.2 Type II - Primary High Strength Steel

Primary high strength steel usage:

Deck legs where indicated on the drawings.

Jacket tubular.

Pile to jacket connection.

Deck tubular.

Plate > 25 mm thick.

Beams with flanges > 25 mm thick.

Where indicated on the drawings.

For tubular, shapes and plate including skelp for fabricated tubular, primary high strength steel

materials shall conform to one of the following standards with additional restrictions given herein:

NEN-EN 10225 Grade S355G7+N

NEN-EN 10225 Grade S355G11+M

NEN-EN 10225 Grade S355G13+N or

NEN-EN 10225 Grade S355G14+N

In case steel is produced according to British Standard (BS7191 Grade 355EM), DIN (DIN17100

Grade ST52-3N) or an other Euronorm standard (Euronorm 10025 Grade S355 J2G3), special high

strength steel shall as minimum conform to the additional requirements here below:

All material shall conform to the chemical requirements of the specification under which it is

produced. Where a lower carbon equivalent is not part of that specification, or where the

specification thickness or strength range is exceeded, the maximum permissible carbon equivalent

shall be 0.43 (ladle), calculated as follows:

43.01556

..

NiCuVMoCrMn

CEC

Charpy V notch test temperature to be -40°C (min av. 27 Joule, min. ind. 21 J.).

Primary High Strength Steel shall be ultrasonically inspected in accordance with EN 10160 class

S1/E2

Hot rolling of tubular has to be done in accordance with DIN 1626, page 3. A mechanical re-test

of the base material shall be carried out as well to prove that material has original values.

Where primary high strength steel is specifically indicated on drawings as “Type II+TMCP” the

ThermoMechanically Controlled rolling Process shall be applied. This steel shall comply to EN

10225 S355G8+M.



Seamless Tubular

Seamless tubular may be API 5L Grade X52 [API spec 5L], normalized and fine grained. If required

by specification seamless tubular can be TTP.Z35 tested as specified in Section 2.2.1.

2.2.3 Type III - Secondary High Strength Steel

Secondary high strength steel usage:

All deck structure main structural beams with flanges < 25 mm.

All main structural plating < 25 mm thick

Where indicated on the drawings.

For tubular, shapes and plate including skelp for fabricated tubulars, secondary high strength

steel; material shall conform to one of the following standards:

NEN-EN 10025 Grade S355J2

NEN-EN 10225 Grade G1+N or

NEN-EN 10225 Grade G2+N

In case steel is produced according to British Standard (BS7191 Grade 355D), DIN (DIN17100

Grade ST52-3U) or an other Euronorm standard (Euronorm 10025 Grade S355 J2G3), special

high strength steel shall as a minimum conform to the requirements here below:

All material shall conform to the chemical requirements of the specification under which it is

produced. Where a lower carbon equivalent is not part of that specification, or where the

specification thickness or strength range is exceeded, the maximum permissible carbon equivalent

shall be 0.43 (ladle), calculated as follows:

43.01556

..

NiCuVMoCrMn

CEC

Charpy V notch test temperature to be -20°C (min av. 27 Joule, min. ind. 21 J.).

2.2.4 Type IV - Mild Steel

Mild steel usage:

All secondary steel.

Removable beams, brackets.

Deck-plating.

Brackets as indicated on the drawings.

Mild steel materials shall conform to one of the following standards with additional restrictions

given herein:

NEN-EN 10025 Grade S235J0

BS 7191 Grade 275 D

DIN 17100 Grade ST-37-2 or 3

NEN-EN 10025 Fe 360 B or C

Charpy V notch test temperature to be 0°C (min av. 27 Joule, min. ind. 21 J.).



2.3 SPECIFICATIONS FOR STEEL

Sections to be used shall conform to the latest editions of Euronorm 19, Euronorm 53, Euronorm

54, Euronorm 55, Euronorm 56 and Euronorm 57.

Flats etc. to be used shall conform to the latest editions of Euronorm 58, Euronorm 59, Euronorm

60 and Euronorm 65.

Hollow square and rectangular sections shall conform to the latest editions of DIN 59410 or

equivalent.

2.4 MISCELLANEOUS STEEL

Grating as per drawing in case of special requirements, further as per table 2.4.1. Grating to be

fastened with clamps or weld studs for 30 mm high and continuous angle iron for 50 mm high, or

approved equivalent. Split-up in grating panels shall be done by fabricator. Grating panels shall

be shaped such that the absence of fasteners can not result in failing of grating panels as a result

of shifting or toppling. Grating floors shall have a 25 mm. clearance from any vessel, sheeting,

pedestal, columns etc. and a clearance of 10 mm from hand railing, baseplates etc. Grating shall

not be cut/adapted etc. after H.D. galvanizing.

Grating shall be ordered from drawings including all changes and attachments.

Table 2.4.1. Grating

Make Use Elevation Coating Type

Thielco 16.000 and above

below 16 000

HDG to EN-ISO 1461,

most stringent

requirement

HDG to EN-ISO 1461,

Most stringent

requirement

A5/30

double serrated/double anti-slip

A5/50

double serrated/double anti-slip

“Approved

Equivalent”

16 000 and above

below 16 000

Idem

Idem

To be submitted for approval

To be submitted for approval

Handrails shall be fabricated from 11/2 inch Schedule 80 pipe for the vertical members and 11/2

inch Schedule 40 pipe for the horizontal members. The handrail panels shall be hot dipped

galvanized after fabrication. Vent-holes necessary for hot dip galvanizing shall be on underside of

handrail and shall be adequately plugged. Handrail pots including attachment shall be fabricated

as per drawings and HD Galvanized as per General Specification 525. The pots shall then be

welded per drawings on the uncoated deck structure, and be coated with the deck structure

without removing the HDG on the inside of the pots. Exact split-up between part to be galvanized

and part to be painted is to be agreed based on an actual application and geometry’s.

The maximum opening in the hand railing should be 0.4 meter between the horizontal members

and the minimum height of the hand railing should not be less than 1.10 meter relative to top of

floor (T.O.G. or T.O.P.). Drawing will prevail. The toe-board should have a minimum height of

150 mm.



All ladders and hand railing shall be finished in such a manner as to leave clean and smooth

surfaces. All welds shall be machined smooth and all burrs removed.

Handrail on jacket level shall be made up from CS Hot Dip Galvanized posts, with SS316 7*7

12mm PVC-covered wire and SS316 or SSA4 fixation material.

Manufactured items such as cleats, shackles, wire rope clips, thimbles, turnbuckles, chain, woven

wire mesh and tie wire shall be SS316 or A4.

Wind-sheeting shall be in accordance with the General Specification for Architectural

Requirements 205.

Doors shall be as defined in General Specification for Architectural Requirements 205.

Timber shall be utility grade hardwood (unless indicated otherwise) and shall be reasonably flat

and straight and free of major defects, such as splits or loose knots.



3.0 FABRICATION

3.1 GENERAL

These specifications and the accompanying drawings are intended to describe the work, material

and quality required to fabricate, coat and load-out the subject platform. All structural fabrication,

except as modified herein, shall be in accordance with API RP 2A, 'Recommended Practice for

Planning, Designing and Constructing Fixed Offshore Platforms', latest edition unless

otherwise specified on the Contract Drawings and ANSI/AWS D 1.1 as noted herein.

All structural fabrication shall be in accordance with the latest editions of AISC and API RP 2A and

ANSI/AWS D 1.1. which ever is more stringent.

3.1.1 Design

Fabrication Contractor shall prepare the required calculations/design work for handling, lifting,

transporting etc. of parts of or complete structures at all stages of the work. Contractor shall

prepare and present drawings and calculations timely for approval by Company and Classification

Authority.

Structural calculations shall be based on elastic properties of shapes and allowable stresses shall

comply with AISC Manual of Steel Construction, Allowable Stress Design, Ninth Edition, 1989.

Further attention is drawn to fabricator’s responsibility in defining the various structures for

constructability, structural attachments to support other disciplines (pipe-supporting and

penetrations, equipment supports, E&I, architectural, HVAC).

3.1.2 Drawings

Fabricator shall check the submitted drawings for fabrication and sea-fastening. If required for

fabrication, additional shop/fabrication drawings shall be made, such drawings shall follow

general practice at fabricators shop, and shall suit normal requirements of industry. Shop drawings

shall be submitted to company for information/ remarks, and shall be submitted as-built after

fabrication. Company supplied AFC (engineering ) drawings shall be marked red, blue and green

for as-built status.

Drawings will further serve QC and allow proper and detailed weld and NDT inspection and

administration.

3.1.3 Marking

For all (pre) fabrication of steel sections, shop administration of fabricator shall be submitted for

approval. In general all steel parts and all other supplied and used items shall be match marked

for field assembly with designated numbers and/or letters, corresponding with the drawings and

material certificates.

Marking system shall suit traceability to satisfaction of Company and if applicable Classifying

Authority (if required also after coating).

3.1.4 Sawing, shearing, flame cutting and chipping

Sawing, shearing, flame cutting and chipping shall be done carefully and accurately and whenever

possible by a mechanical guided tool. Structural sections shall be preferable sawed. If, by

exception, structural sections are cut, the edges shall be ground to a radius of 1.5 mm. All edges

shall be left free of slag.



3.1.5 Laminations, cracks, or split ends

Should laminations, cracks, or split ends be discovered in any pipe, plate or section, the detected

section(s) shall be removed to the satisfaction of the Company and shall not be used in the

fabrication of any other part of the work.

3.1.6 Batten plates, clamps, magnets, setting-up fixtures

Wherever practical, batten plates, clamps, magnets, holding devices or other setting-up fixtures

shall be used in assembling parts of the structures, so as to avoid tack-welding in the weld-groove,

and without damaging (sharp prints) the surface of the structural parts under fabrication.

In fit-up where clamps cannot be used, batten plates or spacer strips shall be used to ensure the

correct root gap prior to tack-welding.

All tack welds shall be cleaned and ground to sound material.

Unless otherwise shown on the drawings, weld connecting structural members shall develop a

strength not less than that of the weaker member.

Cutouts at beam ends for coping shall have an internal radius of 5 millimeters.

3.1.7 Shearing

Shearing of plates, strips, flats and angles is permitted only if their thickness does not exceed

16 mm. Burrs, if any, shall be removed.

3.1.8 Stud welding

Stud welding, for instance for insulation fixtures, is not allowed on main steel.

3.2 PIPE AND EQUIPMENT SUPPORTS, HOLES, CUT-OUTS, PENETRATIONS

All required supports, holes, cut-outs, penetrations etc. shall be provided whether or not indicated

on the drawings for the installation of the work of other trades requiring same. Pipe supports and

equipment supports shall be indicated / integrated on the applicable structural drawings. Holes,

cutouts and penetrations shall be as per approved (typical) details, and the types and locations

shall be indicated on applicable drawings (drawings by fabricator). Holes, cutouts and penetration

details shall ensure possibility of coating according to specifications. For dimensions see

applicable General Specifications.

Care shall be taken not to cut any primary shapes without the prior approval of Company.

3.3 EARTH LUGS

Earth lugs where applicable shall be provided on structural columns near base plate. If fireproofing

is applied, length of lug shall be extended by the fireproofing thickness measured from the outer

edge. Details as per standard drawing GE32 (part of General Specification 613).



3.4 STIFFENERS

Stiffeners shall be fitted accurately and soundly at all contact surfaces with the member or

members to which they are fitted. The contact edges shall be prepared to ensure an even bearing

and shall be suitably prepared for full strength welding, unless otherwise called for on the

drawings.

3.5 SECTIONS OF PIPE

Sections of pipe of the same diameter and wall thickness may be spliced to economically use

materials. No splice shall be located closer to a joint (including mill welds) than four times the

outside diameter of the pipe or a minimum distance of 1.2 m whichever is greater, unless

otherwise noted on the drawings. It is not allowed to have more than one splice in any 3.0 meters

interval of pipe. If pipes contain longitudinal seams, the seams shall be staggered a minimum of

15 degrees at butt joints.

3.6 SECTIONS OF BEAMS

Sections of beams with the same cross-sections may be spliced to economically use the materials.

The use of the beam shall determine the location and frequency of splicing. In cantilever beams,

there shall be no splice located closer to the point of support than half the cantilever length. For

beams employed in any span between supports, there shall be no splice

in the middle one-fourth of any span nor in the one-eight of the span nearest any support. No

two splices shall be located closer together than four times the depth of the beam or a minimum

of 1.2 meters whichever is greater, unless otherwise noted on the drawings.

3.7 MOUSE HOLES

In general for beam-structures with a beam height of 300 mm or more holes with a radius R of 30

mm will be applied; for beams with less height no mouse holes shall be applied.

3.8 SURFACE PREPARATION

Surface preparation for coating shall, as a general rule, be done by dry blast cleaning in

accordance with General Specification 525.

Before further surface preparation all sharp edges shall be rounded to minimal radius of 1.5

mm. Assemblies, constructions or mouse holes that are to be coated, but inaccessible for proper

shot blasting and painting shall be avoided, or shall be closed by welding on/boxing in with a 4

mm plate or alternative proposed by Contractor, only after written approval by Company.

3.9 DECK FABRICATION

Deck plate straightness shall be within 5 mm measured over 1 m.



4.0 WELDING AND INSPECTION

4.1 GENERAL

Unless noted otherwise in these specifications, all structural welding shall be in accordance with

API RP 2A, 'Recommended Practice for Planning, Designing and Construction of Fixed

Offshore Platforms', and the ANSI/AWS and ASME BPV IX codes, latest revision. Existing and

valid procedures, made under Classification Authority supervision and recording, may be

submitted for approval. For the subject situation no re-qualification will be required.

All welding shall be continuous, unless noted otherwise; intermittent welding will not be accepted.

4.1.1 Procedure qualification

Procedure qualification of welds joining High Strength Steel shall include Charpy V-notch impact

testing in accordance with NEN-EN 10045. Test specimens shall be removed and tested as follows

(transverse test):

One test in the weld materials

One test in the line of fusion.

One test in the parent metal 2 mm from line of fusion (in HAZ).

o One test shall consist of three specimens.

o Test temperature to be -40°C for plate thickness > 25 mm and -20°C for plate thickness < 25

mm.

o The average absorbed energy for each test shall be at least 34 Joule with no single specimen

exhibiting less than 27 Joule.

Welding procedure specification (WPS) shall include all relevant information, including but not

limited to welding processes, validity range, material type, position, pre-heat and inter-pass

temperature, filler material(s), max. weaving (if any), and detailed weld preparation. WPS shall be

available at work location. Procedures shall be made available for tack welding, repairs, buttering

and gauging.

At each welding location at least one electronic temperature meter shall be present. For all

welds with a combined wall thickness of 45mm or more, preheating shall be done by means

of electrical elements (mats). Preheat, interpass and cool down shall be controlled.

Influence of weather before complete cool down of the weld area shall be prevented.

4.1.2 Welder qualification

Welders to be qualified for process and position according to relevant codes and witnessed by an

acceptable class authority.

4.2 INSPECTION

Contractor shall visually inspect all welding preparations, welding and welding areas according to

API RP 2A, and ANSI/AWS D 1.1, latest revisions. Quantity and type of Non Destructive Testing

per requirements in this specification. In general NDT as per Table 4.2.1 will be required.

Procedures for NDT and acceptance will be based on ASME Boiler and Pressure Vessel (BPV) Code,

Sections V and VIII.

NDT field execution and reporting shall be in scope of Contractor.



Contractor shall perform dimensional inspection and record and submit results. Dimensional

measurements shall prove fabricated construction is as per drawings.

All inspection shall be recorded to a reasonable extend to satisfaction of the Company (and Class.

Authority if applicable). Administration shall be part of as-built documentation. The weld

numbering shall clearly show the history of a weld.

In case a "negative" reporting system is used, the "Not Acceptable" welds or weld areas shall be

made clearly visible in the overall weld history and reported on paper. These reports and the

reports showing the specific weld (area) that has been repaired and is now acceptable, shall be

filed after acceptance by Company’s inspector.

Table 4.2.1 General indication NDT requirements for structural fabrication.

Type of structure: Type of NDT: % of NDT: Remarks:

Pad eyes, weld preparations

for pad eyes and adjacent

areas

UT

MPI

100%

100%

See Chapter 7.0 of this

specification

Nodes (all types) UT

MPI

100%

100% After 48 hours

Main (bearing) structure

and all under-water or

jacket structure and

attachment-welds to main

structure

UT on all FP-welding

MPI on all welding

and on all scars/tack-

welding

100%

100%

After 48 hours

Secondary structure UT on FP-welding

MPI

15%

15%

After 24 hours,

locations by Company

100 % on repairs

Butt-welds in beams,

tubulars and plate

X- or Y-ray as

alternative for MPI +

UT

Per subject

type

Per subject

type

Seafastening UT on FP-welding

MPI

40%

20%

After 48 hours

Seafastening welds to barge

deck/vessel deck

UT

MPI

40%

100%

After 48 hours

4.3 REPAIRS

Defects, except cracks, in weld deposits may be repaired with prior authorization of the Company

Representative. Removal of defects for repair may be by any method, which produces a clean

uncontaminated surface for installation of the repair weld. Oxygen-acetylene gouging will not be

acceptable. All air-arc gouged surfaces shall be power disk ground to remove residual carbon.

The removal and repairs of cracks in weld deposits or base metal shall be witnessed and approved

by the Company Representative. Any cracks shall be removed by grinding or air-arc gouging to

sound metal (plus 2 inch of sound metal on each end of the crack) as determined by an

appropriate non-destructive testing technique. The surface of the chord member in tubular

intersection joints containing root cracks or transverse cracks shall be magnetic particle and

ultrasonically inspected to detect propagation into the base metal, if any. The intersecting member

shall be completely removed if in the opinion of Company Representative the surface of the chord

member cannot be properly inspected or repaired.



5.0 BOLTED CONNECTIONS

5.1 GENERAL

All bolted connections shall be made with minimum two bolts, 16 mm diameter unless

otherwise indicated on the drawings.

5.2 MATERIAL

Bolts, nuts, etc. shall be of quality 8.8, and shall conform to the latest edition of NEN 81-II and

NPR 1800 (NEN 914, NEN 5513, NEN 5514, NEN 5515, NEN 1555 and NEN 1560). Alternatively

ASTM A-320 (bolts and nuts) or ASTM A-193 (Gr. B7, studs with nuts) may be used.

High strength friction grip (HSFG) bolts, nuts, etc. shall be of quality 10.9 and shall conform to the

latest edition of NEN 81-I and NPR 1800 (NEN 914, NEN 5511, NEN 5512, NEN 5513, NEN 5514

and NEN 5560).

5.3 DESIGN AND USE

High strength friction grip bolts shall be used for the main connections and/or as specified on

the drawings.

Holes for bolted connections shall be drilled and be of a diameter 2 mm larger than that of the

bolt, except in the case of close-tolerance bolts as called for on the drawings.

Slotted hole connections shall be used for connecting to existing adjacent structures, if

applicable, or as indicated on the drawings. Correct type of washer to be applied for slotted holes

(size and thickness).

Bolt shaft shall be long enough to suit the connecting part, washers, nuts and locking nuts and

project at least 3 mm and 10 mm at the utmost, unless indicated otherwise on the drawings.

Heads and nuts of all bolts, other than high strength friction grip bolts, shall be suitably drawn

tight against the work.

Heads and nuts of all bolts shall sit squarely against work or washers where required.

Locking nuts shall be fitted to all bolts, other than high strength friction grip bolts, under each of

the following conditions:

the bolt carries a tension lead

the bolt is connected to vibrating equipment

the bolt is connected to crane beams, lifting beams, trolley hoists, or stairs

the bolt is used on the jacket

called for on the design drawings



High strength friction grip bolt holes shall be drilled, and shall be free from burrs. Punching is

not permitted.

At the time of assembly, the contact surfaces of a high strength friction grip bolt connection shall

be clean and free from paint, scale, loose rust, burrs, dirt, oil, grease and all defects that might

impair a good solid sealing and friction between the surfaces.

All high strength friction grip bolt connections shall be assembled and tightened by a method to

be approved by Company.

Anchor bolts will be specified on drawings or by Company.

5.4 BOLT COATING

For use on structural items below Elevation +16.000 all threaded fasteners shall be cadmium

plated or approved equivalent. For use on structural items above Elevation +16.000 all threaded

fasteners shall be HD galvanized or approved equivalent. Electrolitically galvanized bolts/nuts are

not acceptable.

For small bore fasteners SS A4 grade 70 bolts/units shall be used ( M12); for strength bearing

connections a calculation is required.



6.0 CATHODIC PROTECTION

6.1 GENERAL

The Cathodic Protection System for any under water (or in seabed) structure shall be sacrificial

system consisting of aluminum alloy anodes (unless indicated otherwise).

6.2 DESIGN CRITERIA

Cathodic protection design (if in scope contractor) shall be done according to the latest edition

of DNV RP B401 ref. /15/ and BV number 423 DTO R00E.

Net weight of anodic material in each anode shall be within the weight range applicable to a

twenty year life.

6.3 ANODES

Anode construction shall be in accordance with relevant drawings. Anode material shall be

aluminum alloy of electrochemical value of no less than 2500 ampere hours per kilogram. The

individual anode ampere rating shall correspond to that calculated for a water resistance of no

less than 30 ohm.cm at 50% of the anode cross-sectional area consumed.



7.0 ADDITIONS/AMENDMENTS

7.1 GENERAL

Depending on the nature and use of the structure to be fabricated additional requirements can

be necessary. The additional requirements indicated in this chapter are only applicable for the

indicated type of structure.

7.2 PIPE-SECTIONS TO BE ASSEMBLED

Additional requirements for pipe sections which will be delivered without over-length and with

bevels. The following requirements are applicable in addition to the API Spec. 2B (Section 4.0).

7.2.1 Material length

The length of each pipe shall not vary more than –10 mm or +20 mm total for each item not

beveled or beveled on one side and -0 mm to +3 mm for items beveled on both sides.

7.2.2 Out-of-Roundness

The difference between the major and minor outside diameters shall not exceed 5 mm.

7.2.3 Bevels

All pipes shall be beveled for welding with an angle as indicated. Tolerances for bevel angle and

root face shall be respectively -0° +2.5° (measured from a line perpendicular to the surface of the

pipe) and +0 mm - 2 mm unless otherwise specified. The root face shall be perpendicular to the

longitudinal axis of the pipe within 1 mm per 200 mm diameter, with a maximum allowable

deviation of 4 mm, measured with a square and straight edge across the end of the pipe.

7.2.4 Straightness

The maximum allowable straightness deviation in any 3 m length shall be 3 mm. For length over

3 m, the maximum deviation of the entire length may be computed by the following formula,

not to exceed 9.5 mm in any 12 m length.

3 mm x

(total length m.)

3m

For special items such as jacket legs and piles other more stringent requirements for straightness

and roundness will be applicable (see relevant construction drawings).

7.2.5 Weld inspection

All longitudinal welds shall be 100% U.S. tested. All circumferential welds 100% X-ray. Longitudinal

welds at weld crossing and weld ends shall also be X-ray tested.

7.2.6 Material toughness

Charpy V-notch values as per subject chapter (Materials, Chapter 2) of this specification.



7.3 MAIN PAD-EYES

In addition to other requirements specified either in documents, on drawings or in general codes,

the following will be applicable for main pad-eyes.

7.3.1 Design

The pad-eye design is always subject to check and approval of the installation contractor and the

classifying authority. The design of a pad-eye is amongst others based on weight and C.O.G. of

the item involved. Therefore it can be necessary to leave at least some aspects of the pad-eye

design relatively long on hold, at least until above mentioned aspects are reasonably known to be

accurate.

7.3.2 Material

Selection of material will be a part of the pad-eye design. In general the pad-eye material will be

type I. This includes the main-structure the pad-eye is welded to. For pad-eye components the

charge number(s) must be hard stamped on each individual part, on such a location that the

numbers can be found after assembly of the pad-eye.

7.3.3 Fabrication

The pad-eye main-plate will be taken from the rolled plate such, that the rolling direction of the

plate is the same as the pulling direction for the pad-eye. Assembly/welding shall be planned and

organized such that:

remaining weld tension is minimal,

pre-heating shall be done electrically, temperature controlled and recorded,

once pre-heating has started, fabrication shall be continued till subject part/

beam / area is finished

cool-down shall be slow and controlled.

Above shall be controlled full time by a qualified and dedicated quality-inspector.

7.3.4 Non-Destructive Testing

Components of pad-eyes and adjacent main-structure shall be checked for doubling/material

imperfections. All welding to pad-eyes shall be checked MPI (all welds) and UT (full Penn welds)

at least 48 hours after cool-down. After each use of pad-eyes this NDT-check shall be repeated (if

necessary due to coating this can/shall be done with Eddy current technique).

7.4 PENETRATIONS

Sleeves/penetration in beams:

Penetrations shall not affect structural integrity of the beam, calculation for each typical

application required, in general penetrations near the middle of the web.

Use of rings made from plate, fillet-welded to the web, on one or both sides, can be

considered.

Sleeves to be prefabricated and installed in beam during fabrication of deck and coated with

deck where possible. Material as material for beams.

For dimensions of penetration in deck plating and grating reference is made to standard

drawing A-2076.



8.0 REFERENCES

In this list the reference codes as used in this specification (latest revision to be used) are

linked to the publications they are taken from in alphabetic order:

[1] AISC Specification for Structural Steel Buildings, Manual of Steel

Construction (including supplements and commentary) (Published by

American Institute of Steel Construction).

[2] API RP 2A Recommended Practice for Planning, Designing and Constructing

Fixed Offshore Platforms. (Published by American Petroleum Institute).

[3] API Spec. 2B Fabrication of Structural Steel Pipe.

[4] API Spec. 5L Specification for Line Pipe.

[5] ASME BPV V Non destructive Examination.

[6] ASME BPV VIII Pressure Vessels.

[7] ASME BPV IX Qualification Standard for Welding and Brazing Procedures, Welders,

Brazers and Welding and Brazing Operators.

[8] ASTM A6 Standard Specification for Delivery of Rolled Steel Plates, Shapes, Sheet

Piling and Bars for Structural Use.

[9] ASTM A123 Spec. for Zinc (Hot-dip Galvanized) Coatings on iron and steel products.

[10] ANSI/AWS D1.1 Structural Welding Code - Steel, Latest Edition.

[11] BS 7191 Weldable structural steels for fixed offshore structures

[12] DIN 1543 Stahlbleche über 4.75 mm (Grobbleche), Maß- und Gewichts

abweichungen.

[13] DIN 1626 Geschweißte kreisformige Rohre aus unlegierten Stahlen für

besondere Anforderungen; Technische Lieferbedingungen.

[14] DIN 1629 Nahtlose kreisformige Rohre aus unlegierten Stahlen für besondere

Anforderungen; Technische Lieferbedingungen.

[15] DIN 17100 Allgemeine Baustähle; Gütevorschriften - Steels for general structural

purposes.

[16] DIN 17200 Vergütungsstähle; Gütevorschriften - Quenched and tempered steels.

[17] DIN 17210 Einsatzstähle; Gütevorschriften - Case hardened steels.

[18] DIN 2448 Seamless Steel Pipes.

[19] DIN 59410 Hollow Square and Rectangular Sections for Steel Structures.

[20] DIN 50049 Bescheinigungen über Werkstoff prüfungen - Certificates on material

tests.

[21] DNV Recommended Practice for Testing of Steel Subject to Appreciable 'Z'

Direction Loading, Det Norske Veritas, Engineering Service.

[22] Euronorm 19 Beam Section IPE.

[23] Euronorm 53 Wide Flange Sections.

[24] Euronorm 54 Hot Rolled I-Sections.

[25] Euronorm 55 Hot Rolled Equal T-Sections.

[26] Euronorm 56 Hot Rolled Equal L-Sections.

[27] Euronorm 57 Hot Rolled Unequal L-Sections.

[28] Euronorm 58 Hot Rolled Flat Steel

[29] Euronorm 59 Hot Rolled Square Bar Sections.

[30] Euronorm 60 Hot Rolled Round Bars.

[31] EN 10204 Metallic Products, Types of Inspection Documents.

[32] EN 16085 Ultrasonic testing.

[33] Neptune Specification 525, General Painting and Coating Specification.

[34] NEN 81-I/II Metric Screw Thread (ISO).

[35] NEN 1275 Testing Demands and Methods for Zinc Coated (Galvanizing) Layers of

Steel.



[36] NPR 1800 Nederlandse Praktijk richtlijn 1800, superseeds: NEN 914, 1555, 1560,

5511, 5512, 5513, 5514, 5515.

[37] NEN 1275 Testing Demands and Methods for Zinc Coated (Galvanizing) Layers of

Steel.

[38] NEN-EN 10025 Hot-rolled products of non-alloy structural steels (Euronorm 25).

[39] NEN-EN 10045 Metallic Materials - Charpy impact test.

[40] NEN-EN 10225 Weldable structural steels for fixed offshore structures- Technical

delivery conditions

[41] SEL 072 STAHL-EISEN-Lieferbedingungen 072 (SEL 072) des Vereins Deutscher

Eisenhüttenleute, Ultraschallgeprüftes Grobblech.

[42] Thyssen Steels for Offshore Requirements.

ATTACHMENT 1

MATERIAL GRADES

Type Min. Yield

[N/mm2]

Material reference standard Certificate

EN 10204

Application Typical Usage

I 355 Plates EN 10225 S355G10+N/Z35+US 3.2 Special TTP quality material,

loaded in thickness direction

Jacket leg joints

Padeyes

Deck leg cans

Where indicated on drawings

Seamless RHS

& CRS

EN 10225 S355G15+N/Z35+US

Welded RHS

& CHS

See plates

Sections EN 10225 S355G12+N/Z35+US

I+TMCP 355 Plates EN 10225 S355G10+M/Z35+US 3.2 Special TTP quality material,

loaded in thickness direction with

increased weldability Termo-

mechanically rolled

Where specifically indicated on drawings

Welded RHS

& CHS

See plates

II 355 Plates EN 10225 S355G7+N 3.2 Primary high strength steel Substructure and topside tubulars

Piles

Deck legs

Plate > 25mm

Beams with flanges > 25mm thick


Seamless RHS

& CRS

EN 10225 S355G14+N

Welded RHS

& CHS

EN 10225 S355G13+N

Sections EN 10225 S355G11+N

II+TMCP 355 Plates N 10225 S355G8+M 3.2 Primary high strength steel with

increased weldability Termo-

mechanically rolled

Where specifically indicated on drawings

Welded RHS

& CHS

See plates

III 355 Plates EN 10025 S355J2

EN 10225 S355G2+N

3.2 Secondary high strength steel Plate < 25mm

Beams with flanges < 25mm thick

Where indicated on drawings Seamless RHS

& CRS

EN 10025 S355J2

EN 10225 S355G1+N

Welded RHS

& CHS

Sections

IV 235 EN 10025 S235J0 3.1 Mild Steel

All secondary steel

Deck plating


ATTACHMENT 2

CHARPY-V NOTCH REQUIREMENTS

Type Charpy-V test temperature

[C]

Average / Minimum Individual Value

[Joules]

I -40 27 / 21

I+TMCP -40 50

II -40 27 / 21

II+TMCP -40 50

III -20 27 / 21

IV 0 27 / 21

y

y

w =

f yy

w

y

y f

w*

y

y =

w

f

y

*

y

*

VARIABLE

570

270

150

150

Ø10 DRAIN HOLE

PL.2421x570x6 SS316

STRIP NEOPRENE 60x100

700

1100

6060

WIDTH 50 KG POWDER EXTINGUISHER = 475WIDTH 20 KG CO2 EXTINGUISHER ON WHEELS = 440

A8203

GENERAL

NVT

TOPSIDEFIRE EXTINGUISHER SUPPORT

IN HELI DECK NETTING

1:7.5

00010

0 23.11.10 IV FIRST ISSUE ADJ DZ

1. SEE FOR GENERAL NOTES DWG. A-20012. ALL STEEL TO BE SS316 (U.N.O.)

350

1009

1125

700

111°148°

152°

200

140 27

0

440

U-BOLT 2" C/W NUTS AND WASHERS

PL. 40x6

NUT M10 NYLOC

PL. 50x60x8 SS316

STRIP NEOPRENE 60x100x2

BOLT M10x80

1065

1500

1100

STRIP NEOPRENE 60x100

980

463

L50x50x5 (TYP)

228

30

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