W1440-P4-S-0030_1 Specification for Structural Fabrication, Welding, Inspection & Testing

Tech nip

TECHNIP OCEANIA PTY LTD A.C.N. 062 878 719

1100 Hay Street, West Perth, WA, 6005 Australia Locked Bag 236, West Perth, WA, 6872

Tel: Fax:

CLIENT:

MODEC

PROJECT TITLE:

MUTINEER EXETER FPSO TOPSIDE MODULES

PROJECT NO:

AP003164

61-08-9463 2500 61-08-9463 2501

M ODEC

1

02/02/04

Approved for Use

0

11/12/03

Approved for Use

B

12/11/03

Re-issued for Internal Review

A

13/10/03

DOCUMENT TITLE:

SPECIFICATION FOR STRUCTURAL FABRICATION, WELDING, INSPECTION AND TESTING

DOCUMENT NO:

AP003164-G-JSD-1800-003

CLIENT REF:

W1440-P4-S-0030

CONFIDENTIALITY RATING: C2

THIS DOCUMENT CONTAINS CONFIDENTIAL INFORMATION. ALL RIGHTS (INCLUDING COPYRIGHT, CONFIDENTIAL INFORMATION, TRADE SECRETS AND DESIGN RIGHTS) ARE OWNED BY TECHNIP OCEANIA PTY LTD. NO USE OR DISCLOSURE IS TO BE MADE WITHOUT THE WRITTEN PERMISSION OF TECHNIP OCEANIA PTY LTD. COPYRIGHT TECHNIP OCEANIA PTY LTD. ALL RIGHTS RESERVED.

AP003164-G-JSD-1800-003 Spec For Structural Fab, Welding, lnspec, Test Rev 1.doc

DETAILED DESIGN FOR MUTINEER / EXETER FPSO TOPSIDES Specification for Structural Fabrication, Welding, Inspection and Testing

Doc. No : AP003164-G-JSD-1800-003 Rev : Rev. 1 Page : 2 of 47

RECORD OF AMENDMENT It is certified that the amendments listed below have been incorporated in this copy of the publication.

AMDT NO 1

AMENDED SECTION 2

PARA NO 8

DESCRIPTION OF CHANGES Revised. Vendor to supply “black steel”.

AP003164-G-JSD-1800-003 Spec For Structural Fab, Welding, Inspec, Test Rev 1.doc



HOLD'S STATUS SHEET This revision has the following HOLD's

SECTION

PARA NO

DESCRIPTION OF HOLD




TABLE OF CONTENTS 1.0

GENERAL................................................................................................................ 7

1.1

Introduction .............................................................................................................. 7

1.2

Document Purpose .................................................................................................. 7

1.3

Scope of Work ......................................................................................................... 7

1.4

Definition of Terms................................................................................................... 8

1.5

Referenced Documents ........................................................................................... 8

1.6

Vendor Responsibility ............................................................................................ 10

1.7

Documentation....................................................................................................... 11

1.8

After Fabrication .................................................................................................... 13

1.9

Abbreviations ......................................................................................................... 13

2.0

MATERIALS .......................................................................................................... 15

2.1

General .................................................................................................................. 15

2.2

Transportation, Storage And Handling Of Materials............................................... 15

2.3

Used Materials ....................................................................................................... 15

2.4

Classification and Certification of Structural Steels................................................ 15

2.5

Structural Steel Types............................................................................................ 15

2.6

Material Identification ............................................................................................. 16

2.7

Miscellaneous Steel ............................................................................................... 16

2.8

Pre-fabrication Paint Priming ................................................................................. 16

3.0

WELDING .............................................................................................................. 17

3.1

General .................................................................................................................. 17

4.0

WELDING CONSUMABLES.................................................................................. 17

4.1

General .................................................................................................................. 17

4.2

Processes .............................................................................................................. 18

4.3

Types of Electrodes, Wires and Fluxes ................................................................. 18

4.4

Conditions and Storage ......................................................................................... 19




4.5

Heating and Baking Requirements ........................................................................ 19

5.0

QUALIFICATION OF WELDING PROCEDURE..................................................... 21

5.1

General .................................................................................................................. 21

5.2

Parameters in Welding Procedure Specification.................................................... 21

5.3

Welding Procedure Qualification Test.................................................................... 21

5.4

Essential Variables in Qualification of Welding Procedures................................... 22

5.5

Procedure Qualification Record ............................................................................. 22

5.6

Testing Requirements for Procedural Qualification Test........................................ 22

5.7

Acceptance Criteria and Retest ............................................................................. 22

5.8

Welding Procedure Register.................................................................................. 23

6.0

QUALIFICATION OF WELDERS AND WELDING OPERATORS.......................... 24

6.1

General .................................................................................................................. 24

7.0

PRODUCTION WELDING...................................................................................... 26

7.1

General .................................................................................................................. 26

7.2

WELDING SEQUENCE ......................................................................................... 26

7.3

Weld Preparations ................................................................................................. 26

7.4

Weld Execution...................................................................................................... 27

7.5

Preheating and Interpass Temperatures................................................................ 29

7.6

Stress Relieving - Post Weld Heat Treatment........................................................ 30

8.0

FABRICATION AND DELIVERY............................................................................ 32

8.1

General .................................................................................................................. 32

8.2

Material Preparation............................................................................................... 32

8.3

Stiffeners ............................................................................................................... 33

8.4

Splices ................................................................................................................... 33

8.5

Camber .................................................................................................................. 34

8.6

Laying-Out, Alignment and Fit-Up.......................................................................... 34




8.7

Temporary and Non-Structural Attachments and Cut-Outs.................................... 35

8.8

Finishing of Surfaces ............................................................................................. 35

8.9

REPAIR AND REMEDIAL PROCEDURES ............................................................ 36

8.10

ANCILLARIES AND TEMPORARY WORKS ......................................................... 36

9.0

DIMENSIONAL CONTROL .................................................................................... 38

9.1

General .................................................................................................................. 38

9.2

Tolerances for Structural Components and Sub-Assemblies................................. 39

10.0

INSPECTION AND TESTING ................................................................................ 40

10.1

General .................................................................................................................. 40

10.2

Inspection Requirements ....................................................................................... 40

10.3

Extent of Inspection ............................................................................................... 41

10.4

Padeye Testing and Marking ................................................................................. 45

11.0

FIELD INSTALLED ITEMS .................................................................................... 46

12.0

ADDITIONAL REQUIREMENTS ............................................................................ 47

12.1

Painting.................................................................................................................. 47

12.2

Pre-Commissioning................................................................................................ 47

12.3

Final Weighing & COG Determination ................................................................... 47

12.4

Loadout.................................................................................................................. 47



1.0

GENERAL

1.1

Introduction


The Mutineer Exeter Project is located in the North-West Shelf of Australia within the petroleum permit WA-191-P. Santos Ltd is the major operator of this field with MODEC as main contractor to supply and deliver the FPSO including the topside modules. MODEC have sub-contracted the supply and delivery of Process Modules A and B and Flare Knockout Module to TOPL. All equipment and activities shall meet the requirements of this specification and of the codes, standards and specifications nominated herein. This Specification shall be read in conjunction with Project Document No.: AP003164-GJSD-1800-002 - “Specification for Structural Materials” Where it is necessary for certain structural steel components to be installed offshore, compliance with all the requirements of this Specification shall also mean that such components shall be trial assembled onshore to the maximum extent practicable to ensure subsequent correct fit, whenever directed by COMPANY. 1.2

Document Purpose This Specification covers the fabrication, welding, inspection and testing of structural steels with nominal yield strengths of less than or equal to 358 MPa as defined in the material specification of Project Document No.: AP003164-G-JSD-1800-002 “Specification for Structural Materials”.

1.3

Scope of Work This specification applies to the following components of the FPSO Topside Modules: i)

Primary steel that includes deck beams, plan bracing, support columns, vertical bracing and their associated connections.

ii)

Secondary steel that includes deck stringers, trimmers, equipment supports, pipe racks/supports and their associated connections.

iii) Tertiary steel that includes deck grating/plating, access platforms, stairways, handrails, ladders etc. iv) Temporary steel for module handling purposes during load-out, transportation and installation. v)

Interface connections between underside of module support columns/vertical bracing and FPSO support stools.

vi) Module lifting padeyes. vii) Decks shall be build with bottom of columns not less than 1500 mm above ground level to assist installation of seafastening steel prior to loadout.



1.4


Definition of Terms The following terms as used in this specification, assume the meanings given below: Company

:

Technip Oceania Pty Ltd (TOPL) sub-contracted by MODEC to supply Topside Modules for the FPSO

Vendor

:

The person, firm or company specified in the Order and to whom the Order is issued to fabricate and supply the Topside Modules as further defined in the Terms and Conditions of Contract.

Inspector

:

Such persons as appointed by the Company to monitor the fabrication and supply of the Work.

Certifying Authority

:

ABS is the independent, accredited, third party certification authority appointed by the COMPANY to ensure that the steel supply and fabrication complies with the relevant codes and standards.

Client

MODEC is COMPANY'S client and major contractor for the supply of the FPSO.

Sub-vendor

:

A person, firm or company authorised to undertake work on behalf of the Vendor.

Contract Drawings

:

Design drawings, with AFC status, issued by the Company to the Vendor.

1.5

Referenced Documents

1.5.1

Base Specifications a)

Materials All steel materials shall meet the requirements of Project Document No.: AP003164G-JSD-1800-002 - "Structural Specification for Materials" and Section 2.0 of this Specification.

b)

Welding All welding, temporary or permanent, shall meet the requirements of the latest edition of AWS D1.1 "Structural Welding Code-Steel” and this Specification.

c)

Inspection and Testing All inspection requirements shall meet ABS requirements, AWS D1.1 and Section 10.0 of this Specification.

d)

Company Specifications •

AP003164-G-JSD-1800-001 - Structural Basis of Design

•

AP003164-G-JSD-1800-002 - Structural Specification for Materials

•

AP003164-G-JSD-2310-0001 - Painting Specification

•

AP003164-G-JSD-1800-005 - Structural Specification for Equipment Skids


DETAILED DESIGN FOR MUTINEER / EXETER FPSO TOPSIDES Specification for Structural Fabrication, Welding, Inspection and Testing 1.5.2


Codes, Standards and references a)

Unless otherwise specifically indicated, the following standards, rules and codes shall govern the works. These shall be considered complimentary to and providing further detailed requirements and recommendations to those stated in this Specification and shall be complied with. Where, however, the requirements of this Specification are in conflict with or expand the above requirements, this Specification shall prevail.

b)

All the standards, rules and codes stated below are to be the latest editions at the commencement of the Works. i)

Australian National Regulations

ii)

American Petroleum Institute (API)

iii)

iv)

v)

•

API 5L - Specification for Line Pipe.

•

API RP 2A - Recommended Practice For Planning, Designing And Constructing Fixed Offshore Platforms

•

API 2H - Specification for Carbon Manganese Steel Plate For Offshore Platform Tubular Joints.

American Institute of Steel Construction (AISC) •

Code of Standard Practice For Steel Building And Bridges

•

Specification for Structural Steel Buildings.

American Welding Society (AWS) •

AWS D1.1 - Structural Welding Code-Steel

•

AWS A.2.4 - Symbols For Welding And Non Destructive Testing

•

AWS A.3.0 - Welding Terms And Definitions

•

AWS A.5.1 -Specification For Carbon Steel Covered Arc Welding Electrodes

•

AWS A.5.5 - Specification For Low Alloy Steel Covered Arc Welding Electrodes

•

AWS A.5.17 - Specification For Bare Carbon Steel Electrodes For Submerged Arc Welding

•

AWS A.5.18 - Specification For Carbon Steel Filler Metals For Gas Shielded Arc Welding

American Society for Testing and Materials (ASTM) • • •

vi)

ASTM A6 - Specification For General Requirements For Delivery of Rolled Steel Plates, Shapes, Sheet Piles And Bars For Structural Use ASTM A36 - Specification For Structural Steels ASTM A572 - Specification For High-Strength, Low-Alloy Columbium - Vanadium Structural Steels

American Bureau of Shipping (ABS) • •

Guide for Building and Classing Floating Production Installations Guide for Building and Classing Facilities on Offshore Installations


DETAILED DESIGN FOR MUTINEER / EXETER FPSO TOPSIDES Specification for Structural Fabrication, Welding, Inspection and Testing •


Rule Requirements for Materials and Welding – Part 2

1.6

Vendor Responsibility

1.6.1

General The Vendor shall operate a documented Quality, Health, Safety and Environmental Management System in accordance with ISO 9002 or Company approved equivalent standards. The vendor shall provide documentary evidence of implementation of the above systems including audit reports /non-conformance reports as requested by the Company. The Vendor shall ensure that all materials, workmanship, inspection and deliverables conform to the requirements of the Drawings and this Specification. The Vendor shall allow access to personnel and records for the purpose of the Company as required.

1.6.2

Personnel The Vendor shall have fully experienced supervisory personnel in charge of all aspects of the work, and shall employ only fully experienced tradesmen to carry out the work.

1.6.3

Materials The checking, testing, preparation, fabrication and corrosion protection of all materials to be used shall be the responsibility of the Vendor, and is to be in accordance with the requirements of this Specification and the Certifying Authority.

1.6.4

Subcontracts The Vendor shall obtain approval from the Company prior to subcontracting any work. The Vendor shall demonstrate that any Sub-Vendor nominated is capable of producing work to the required standard. Vendor shall be responsible for all of its Sub-Vendors. Company reserves the right to oppose the choice of any Sub-Vendor who will not fulfil the quality and schedule requirements.

1.6.5

Substitutions and Modifications The Vendor shall make no substitution of materials and/or modification of details, without the prior approval of the Company. The Vendor shall submit in writing all such changes duly documented to the Company for approval.

1.6.6

Errors and Omissions It is an obligation of the Vendor to check the contract documents and Drawings and to notify the Company of any errors or omissions.

1.6.7

Conflicts and Deviations All conflicts between requirements of this Specification, related contract documents, national standards, codes of practice, and the contract shall be referred to the Company for clarification. Where conflicts occur, the generalised order of precedence shall be as follows: a) b) c)

Statutory Requirements Design Drawings This Specification


DETAILED DESIGN FOR MUTINEER / EXETER FPSO TOPSIDES Specification for Structural Fabrication, Welding, Inspection and Testing d) e) f)


Other Specifications Minimum Code or Standard requirements Contractor Quality Plan

In no case will this specification release the Vendor from its responsibilities and obligations with regards to Codes, Rules and Regulations generally applicable to the fabrication and assembling of steel equipment. 1.7

Documentation

1.7.1

Prior To Fabrication Prior to commencement of any part of the fabrication, VENDOR shall submit the following documentation for COMPANY approval: a)

Schedule of work to illustrate how delivery will be met in accordance with COMPANY supplied delivery schedule. Shall include shop detail drawings, procurement of material, fabrication sequence, test & inspection, painting etc.

b)

Inspection and Test plan.

c)

Mill certificates for VENDOR supplied materials.

d)

Fabrication and assembly procedures, welding sequence and erection sequence. This is to include the welding procedure specification to be applied, welding sequence and direction, and number and location of welders at each stage of assembly.

e)

Shop detail/fabrication drawings which shall include all pertinent information required for fabrication and shall include material grade, section size, dimensions, stiffening plates etc. VENDOR to generate such drawings from TOPL supplied AFC drawings.

f)

Drawings and calculations of temporary works, inclusive of support points, jacking points and sling points, approved by a qualified engineer.

g)

List of proposed welding consumables and their areas of application including detailed control procedures for consumable handling, baking, storage and issue.

h)

Welding procedures, repair welding procedures with their supporting procedure qualification records and including weld maps.

i)

Certificates of welders, welding operators and tackers qualified in accordance with this Specification complete with list of welder identification numbers and photographs.

j)

Key plan showing an unambiguous member identification and weld marking scheme (weld map).

k)

Inspection procedures and detailed report sheets for non-destructive testing and inspection. This shall include separate sheets for Visual, Radiography, Ultrasonic, Dye Penetration, Magnetic Particle, Painting and Coating.

l)

Identification and control procedures for materials.

m) Procedures for control of tolerances during fabrication and procedure for distortion rectification. n)

Detail procedures for welding equipment maintenance and calibration.

o)

Qualification certificates for all inspection personnel.

p)

Post-Weld Heat Treatment.




q)

Structural design calculation of equipment skids in accordance with Project Document No.: AP003164-G-JSD-1800-005 - "Structural Specification for Equipment Skids".

r)

A complete weighing procedure, which shall also include the COG determination, for the completed modules.



1.7.2


During Fabrication As the work progresses, the VENDOR shall provide the following:

1.8

a)

As-built dimensional survey records which shall be updated continuously.

b)

Where traceability is required, plans marked to relate certificate references for all materials to its final position in the structure.

c)

NDT test reports (original only) including radiographs and key plans marked showing final identification numbering, test report numbers and the results. Summary sheets for NDT test reports for each joint shall be kept up to date as the work progresses.

d)

As-built drawings and Specifications which shall show in detail the manner in which the facility was constructed and shall reflect all changes, additions, corrections or revisions made during the course of construction. The objective being to build up a full documented history of the Construction Work.

e)

Weight control report shall be produced and updated continuously.

After Fabrication After fabrication is completed, the VENDOR shall provide a full MDR report, which shall include as a minimum the following:

1.9

a)

Welder qualifications

b)

Weld procedures and qualifications

c)

Welder traceability

d)

Material traceability

e)

Mill certificates

f)

Weld consumable certificates

g)

Inspection and testing certificates

h)

Paint report

i)

As-built drawings and weight control report

j)

Final measured weight and centre of gravity for all three modules

Abbreviations ABS

American Bureau of Shipping

AFC

Approved for Construction

API

American Petroleum Institute

ASNT

American Society for Non-destructive Testing

ASTM

American Society for Testing and Materials

AWS

American Welding Society

CAR

COMPANY Authorised Representative

COG

Centre of Gravity

CSWIP

Certification Scheme For Welding Inspection Personnel

DPI

Dye Penetrant Inspection


DETAILED DESIGN FOR MUTINEER / EXETER FPSO TOPSIDES Specification for Structural Fabrication, Welding, Inspection and Testing E&I

Electrical and Instrumentation

GTAW

Gas Tungsten Arc Welding

GMAW

Gas Metallic Arc Welding

MPI

Magnetic Particle Inspection

NDT

Non Destructive Testing

PQR

Procedure Qualification Record

PWHT

Post Weld Heat Treatment

PQR

Procedure Qualification Record

RT

Radiographic Testing

SAW

Submerged Arc Welding

SMAW

Shielded Metallic Arc Welding

TOPL

Technip Oceania Pty Ltd

TTP

Through Thickness Properties

UT

Ultrasonic Testing

WPS

Welding Procedure Specification

WQT

Welder Qualification Test




2.0

MATERIALS

2.1

General


This section shall be read in conjunction with Project document no.: AP003164-G-JSD1800-002 - “Specification for Structural Materials”. 2.2

2.3

Transportation, Storage And Handling Of Materials a)

VENDOR shall ensure adequate protection to all steelwork during any loading and transportation activities.

b)

VENDOR shall provide nylon or similar lifting slings during handling or lifting operations; wire ropes or chain slings will not be permitted.

c)

The steelwork shall be stored above ground on pallets, timber blocks or other similar supports, be kept above the level of any standing water and be kept free from dirt, grease, paint spray, etc. and shall be protected from harmful environments.

d)

Particular care shall be taken in storage and handling of parts which have been metal sprayed, galvanised, painted, etc., and should the coating be damaged, it shall be restored by an approved method, and be compatible with the particular coating.

Used Materials Temporary bracing, erection aids, scaffolding and materials and equipment for testing shall be furnished by VENDOR and shall be safe, serviceable and adequate.

2.4

Classification and Certification of Structural Steels Refer Project Document No.: AP003164-G-JSD-1800-002 - “Specification for Structural Materials”.

2.5

Structural Steel Types Steel have been classified into three main types as follows: TYPE I STEEL :

Primary Structural Steel – High Strength

Primary structural steel - high strength, is steel with minimum yield strength of 345 MPa and is used in members essential to the overall integrity of the structure and for other structural members of importance to the operational safety of the structure. Example: Support Columns & Braces, Primary deck plan members, (pipe racks optional) etc. TYPE II STEEL : Thickness Properties

Primary Structural Steel – High Strength with Through

Primary structural steel - high strength with through thickness properties (TTP), is steel with minimum yield strength of 345 MPa and is used in members essential to the overall integrity of the structure, where stress concentrations are high and where the stresses in the Z (thickness) direction may lead to lamellar tearing. Example: tubular chords at chord/brace connection lift points/padeyes TYPE III STEEL :

Secondary Structural Steel – Mild Steel




Secondary structural steel - mild steel, is steel with specified yield strength between 240 MPa ~ 345 MPa and is used in members which are not essential to the overall integrity of the structure. Typical Examples: Handrails, Grating, Floor plate, Grating support stringers, Pipe supports, etc. 2.6

Material Identification Refer Project Document No.: AP003164-G-JSD-1800-002 - “Specification for Structural Materials”.

2.7

Miscellaneous Steel

2.7.1

Bolts, Nuts And Washers Refer Project Document No.: AP003164-G-JSD-1800-002 - “Specification for Structural Materials”.

2.7.2

Grating Refer Project Document No.: AP003164-G-JSD-1800-002 - “Specification for Structural Materials”.

2.7.3

Deck Plate The use of chequer plates shall be avoided where possible and only be installed when indicated on the AFC Drawings. They shall be of the type where no slippery surfaces will be created due to standing water or oily products.

2.8

Pre-fabrication Paint Priming VENDOR shall procure or provide structural steel sections unprimed “black steel” in accordance with project document No.: AP003164-G-JSD-1800-002.



3.0

WELDING

3.1

General


•

All welding, temporary or permanent, shall meet the requirements of the latest edition of AWS D1.1 "Structural Welding Code-Steel", as modified by this Specification and ABS requirements.

•

All welds shall be full penetration and continuous butt welds except where noted on drawings.

•

All fillet welds indicated on AFC drawings given as leg size.

•

All touching surfaces shall be seal welded with continuos 3 mm minimum fillet welds e.g. deck plate on beams/stringers. All seal plates shall be 6mm minimum thickness e.g. open end tubulars. Exception is deck grating on beams/stringers which shall be fastened using clips.

•

ABS qualified welders shall carry out all welding and welding operators using qualified welding procedures in accordance with this Specification.

•

All welding (including tack welding) shall be accomplished using low hydrogen process. Automatic submerged arc (SAW) or manual shielded metal arc (SMAW) welding processes shall be used wherever practical. Other welding processes such as flux cored arc welding (FCAW) or gas metal arc welding (GMAW) may be accepted for certain applications, upon written approval. Flux cored arc welding (FCAW) processes will not be allowed for welding of any installation aids such as padeyes, lifting / launching lugs, guide / bumper system etc.

4.0

WELDING CONSUMABLES

4.1

General Welding wire and flux for submerged arc welding shall conform to ABS requirements and AWS A5.17 or AWS A5.23. Unless otherwise approved by the COMPANY, welding electrodes for manual shielded metal arc welding shall conform to low hydrogen (E70/E60 see 4.3.1 below) classification of AWS A5.1. a)

The electrodes, wires and fluxes used in fabrication shall be selected to produce welds with mechanical properties equivalent to those required for the base metal or as specified by COMPANY.

b)

When steels of different strengths are joined, the tensile properties of the weld metal shall be matched to the lower strength steel.

c)

The welding consumables applied shall be certified and brand approved by ABS or any other internationally recognised certifying authority to Company approval.

d)

All welding processes and consumables shall be ”low hydrogen”, capable of producing less than 10ml of hydrogen per 100g of deposited weld metal when tested in accordance with the requirements of AWS D1.1. Electrodes shall comply with the requirements of AWS D1.1.

e)

Flux for submerged arc welding shall be free from any active weld metal alloying additions.



4.2


f)

Consumables shall deposit weld metal having minimum yield and ultimate tensile strengths at least equal to that specified for the parent metal.

g)

The Vendor shall submit to the Company batch certificates for all consumables used during fabrication.

h)

Consumables shall be conditioned and handled in accordance with Manufacturers’ recommendations or a minimum of section 4.4 and 4.5 below.

Processes Welding processes approved for this project shall be as follows: a) b) c)

Shielded Metal Arc Welding Submerged Arc Welding Flux-cored Arc Welding

-

SMAW SAW FCAW

Other welding processes may only be used with the prior approval of the Company. If the Vendor desires to use an alternative process, a proposal shall be submitted at the bid stage. The Vendor will be required to identify areas of intended use together with full details of the processes and consumables proposed. The use of Gas Metal Arc Welding (GMAW), not of the Pulse/Synergic type, is not allowed unless all fillet welds are 100% MP examined and all full & partial penetration welds are 100% UT and 100% MP examined and is subject to company approval. 4.3

Types of Electrodes, Wires and Fluxes

4.3.1

Electrode Strength Grades Electrode strength grade shall be selected based on the parent metal in accordance with the following table: Table 4.3.1

Electrode Strength Grades

Steel Type

Electrode Grade

Comments

Type I – primary

E70XX

High strength steel

Type II – primary E70XX with TTP

High strength steel

Type III – E60XX secondary/tertiary

Low strength steel – mild steel grade

Type I with Type III

High strength steel governs

E70XX

Or Type II with Type III

Refer to AP003164-G-JSD-1800-002 – “Specification for Structural Material” for the appropriate standard or equivalent steel grades associated with the steel types (e.g. Type I Steel: ASTM A572 Grade 50). 4.3.2

Wire and Flux for Submerged Arc Welding Wire and flux shall be carefully selected and the flux shall be of the fully basic type. The storage and use of wire and flux shall be as recommended by the manufacturer. The flux supplier shall define the range of chemical composition of wire to be used for his particular




flux. No low-alloy wires shall be accepted. VENDOR shall submit the proposed wire and flux for approval. 4.3.3

Wire for Gas Metal Arc Welding The gas metal-arc process may only be used on mild steel in enclosed shop fabrication conditions, and provided that the filler wire selected is such that the welds produced have the same mechanical properties as the base metal.

4.4

Conditions and Storage VENDOR shall establish detailed procedures for electrode handling, storage and issuing procedure for COMPANY written approval. The procedures shall comply with ABS requirements and AWS D1.1 Section 5, along with the following:

4.5

•

A positive means of identifying wires, flux or electrodes shall be established, maintained, and submitted to COMPANY for approval.

•

Any consumable unmarked, or showing signs of damage or deterioration, be it electrode, wire, gas or flux, shall be discarded.

•

Low hydrogen electrodes shall not be stored in heated cabinets containing electrodes of other types as approved by the COMPANY.

•

Electrodes, wire spools for automatic and semi-automatic processes shall be stored in cabinets with supplier wrapping not removed and remain clearly identifiable up to the time of usage. Unidentifiable wire shall not be used.

•

All welding consumables, electrodes, wires and fluxes shall be stored in a dry area where humidity can be controlled, at a temperature of not less than 20ºC (68ºF). All welding electrodes shall be supplied in clearly identified, hermetically sealed containers.

•

Submerged arc flux shall be supplied in clearly identified moisture proof containers.

•

Submerged arc, gas metal arc and flux cored welding wire shall be clearly identified.

•

Agglomerated/bonded submerged arc fluxes shall only be recycled once and shall be free of flux, mill scale, dirt and other foreign matter. No flux shall be used from the floor or after exposure to dampness. Compressed air shall not be used for feeding or recycling flux. Flux design single pass joints shall not be used for multi-pass joints.

•

All manual-type electrodes shall be properly identified up to the time of usage. Each electrode shall be distinguishable by colour code marking. If colours are destroyed by baking, handling or other causes, the electrodes shall be replaced with properly identified electrodes. Submerged arc flux, and submerged arc, gas metal arc and flux cored wires, shall be clearly identified with manufacturer’s grade and batch number.

•

Each batch of wire and flux shall be labelled with the information from the supply containers. Unidentified wire, flux, electrodes and other welding consumable shall not be used.

Heating and Baking Requirements Heating, baking and rebaking requirements shall comply with ABS requirements and AWS D1.1 Section 5.3/Annex VIII along with the following: •

Vendor shall have baking ovens and heated storage cabinets with automatic heat control and temperature gauges and each welder shall be supplied with a heated quiver.




•

All low hydrogen electrodes shall be purchased in hermetically sealed containers or shall be rebaked prior to use. Immediately after opening the hermetically sealed container, electrodes shall be stored in ovens held at temperatures of at least 1200 C.

•

Prior to use, low-hydrogen electrodes shall be baked at a temperature of 300ºC (570ºF) for a minimum period of one (1) hour, or in accordance with the manufacturer’s instructions, to give a weld metal deposit with a hydrogen content not exceeding 10 ml of hydrogen per100 grams of deposited welded metal.

•

Submerged arc, gas metal arc and semi-automatic consumables shall be withdrawn from the storage as required for immediate use. Unused consumables shall be returned to the storage on completion of the welding operation. After issue from storage, flux shall be held in a heated 70°C (160°F).

•

Following baking, the electrodes shall be transferred to a heated storage cabinet at 150ºC (300ºF) for later use. Low-hydrogen, manual and metal arc electrodes shall be withdrawn as required for immediate use and held in a heated quiver at a minimum temperature of 75ºC (170ºF). All low-hydrogen electrodes unused after a period of eight (8) hours shall be returned and re-baked as specified above before being reused for welding. Low hydrogen electrodes left out of heated quivers for more than four (4) hours shall be discarded or rebaked as specified above. Under humid conditions this eight (8) hour period shall be reduced at the discretion of the Company or based on manufacturer’s recommendation. No electrodes shall be left lying around the site/workshop. Electrodes so left shall be scrapped and removed.

•

Electrodes shall be rebaked only once. Returned electrodes shall be marked prior to rebaking.



5.0

QUALIFICATION OF WELDING PROCEDURE

5.1

General


Detailed welding procedures for typical structural welding of plates, shapes and tubular members shall be established and qualified in accordance with ABS requirements and AWS D1.1 and as further required in this Specification. All procedures shall be submitted to COMPANY for review and approval before any welding is commenced and COMPANY's representative shall witness the procedure test. Procedures previously qualified by VENDOR and witnessed and endorsed by a reputable independent certifying party for other work are acceptable without running another procedure test at the discretion of COMPANY. The major welding parameters must be the same. Welding procedures and qualification records already qualified for non-COMPANY work shall be acceptable solely at the discretion of COMPANY. Any structural repair welding shall be limited to two attempts and approved by COMPANY. Repair welding procedures shall be established and qualified. See Section 8.9. 5.2

Parameters in Welding Procedure Specification A Welding procedure specification (WPS) shall contain the following parameters with all explanatory details necessary:

5.3

a)

Material specification of the base metal(s)

b)

Welding process(es), manual or semi-automatic.

c)

Material thickness and diameter range for which the procedure is valid.

d)

Geometry of welding groove showing allowable tolerances.

e)

Root gap showing allowable tolerances.

f)

Welding position and direction.

g)

Filler metal specification and brand.

h)

Filler metal classification.

i)

Specification of flux.

j)

Gas shielding - flow, mixture and composition.

k)

Number and sequence of passes.

l)

Welding current, voltage, polarity and heat input(including ranges).

m)

Travel speed and electrode runout length for each pass and range.

n)

Preheat and interpass temperatures.

o)

Post weld heat treatment including heating and cooling rates.

p)

Method of cleaning and gouging.

Welding Procedure Qualification Test a)

Welding Procedure Qualification tests shall be carried out prior to any welding, to verify the WPS and shall simulate, as far as is practicable, the conditions and




materials to be used for production welding. Limitations imposed by the essential variables of the procedure qualification shall be adhered to in production welding.

5.4

b)

Changes in any of the essential variables (See Section 5.4) will call for a new qualification test.

c)

Changes in one or more of the non-essential variables will not call for a new qualification test, but a new WPS is required.

d)

Any WPS qualification for COMPANY shall be witnessed by COMPANY and ABS with ownership of the WPS/PQR shall be jointly shared between both parties.

e)

Proposed WPS packages that will be qualified shall be submitted for COMPANY acceptance

Essential Variables in Qualification of Welding Procedures Any changes in the essential variables listed in AWS D1.1 paragraph 4.7, table 4.5 shall require the resubmission of a new WPS and a complete qualification of the procedure.

5.5

Procedure Qualification Record The specific facts from the WPS and test results from the welding procedure qualification test shall be recorded in the procedure qualification record (PQR). The applicable WPS with the PQR shall be submitted to COMPANY for approval before any production welding is commenced. At the discretion of COMPANY, test results from previous jobs or contracts may be acceptable but only when the essential parameters are similar, original copy of the PQR is available and the PQR is endorsed by a third party independent certifying authority acceptable to ABS. The form used for the WPS and PQR shall be such as described in AWS D1.1. However, the parameters stated in Section 5.2 above shall be recorded.

5.6

Testing Requirements for Procedural Qualification Test An independent qualified testing laboratory shall perform all qualification testing.

5.6.1

Non Destructive Testing and Destructive Testing Each test specimen shall be non-destructively or destructively tested for soundness using methods outlined in the AWS D1.1 section 4.8.

5.7

Acceptance Criteria and Retest The weld shall be inspected or tested in accordance with AWS D1.1 for acceptance or retest. Unacceptable defects evaluated by visual, MPI, DPI, radiographic, ultrasonic and macro etch testing shall be cause for rejection for a retest. In this case a new test weld shall be required.

5.7.1

When Retest Is Allowed When one of the following mechanical test specimens fail to meet the required acceptance criteria, two additional specimens shall be prepared for retesting. The location of the two additional specimens shall reflect the location of the failed specimen. If one or both of the retest specimens fail, then this shall be cause for rejection. A new test weld shall be required.



5.8

a)

Tensile test

b)

Bend test

c)

Impact test (when applicable)

d)

Hardness test


Welding Procedure Register The Vendor shall maintain a register of welding procedures, including NDT procedures, approved by the Company and shall ensure that only registered, approved procedures are employed in the fabrication.




6.0

QUALIFICATION OF WELDERS AND WELDING OPERATORS

6.1

General

6.1.1

Qualifications Required Welders and welding operators shall be qualified in accordance with the requirements of ABS, AWS D1.1 and this Specification. Only qualified welders shall be employed during the fabrication including tack welding, structural welding and repair welding of any structural steel part. They shall only perform welding for positions and processes for which they are qualified. Backing materials shall not be used during testing. All welders who will perform the work in this project shall be qualified in accordance with this specification.

6.1.2

Witness And Approval Of Test Before Welding All welders and welding operator's tests shall be witnessed and approved by COMPANY before the welder or welding operator is permitted to work on the structure. The decision by COMPANY regarding qualification of any welder or welding operator shall be final. Evidence of previous qualification tests may be accepted solely at the discretion of COMPANY Representatives provided:

6.1.3

•

WQT not done more than a year ago,

•

record endorsed by a third party independent certifying authority,

•

welder performed welding work for the past 6 months.

Welder Identification System An identification system shall be worked out for welders and welding operators. The system, which shall include a numbering and identification card index, shall be established and agreed with COMPANY. Whilst on the Works, the welder/welding operator shall always be identifiable by a badge bearing his name, his photograph and his identification number. COMPANY representatives will dismiss welders and welding operators not wearing their badges from the Works. In the event that a welder leaves the Works, his welder and identification mark shall not be assigned to another welder employed on the Works.

6.1.4

Marking Of Welds Each qualified welder and welding operator shall be supplied with an identification marker. The welder shall clearly mark the plate or pipe adjacent to his weld using soft die stamps or non erasable paint with the identification mark assigned to him in his qualification certificate. Tack welding of components need not be marked.

6.1.5

Applicability Of Qualifications The qualified welders and welding operators can only, after ABS acceptance, carry out the work on welding the type, process and positions of weld for which their qualification test so qualifies them. Violators shall be removed from the WORK.

6.1.6

Base Material As far as is practicable, welders and welding operators shall be qualified on the same material to be used for fabrication. Similar types of materials may be substituted at the discretion of COMPANY provided that it can clearly be demonstrated that the weldability is equivalent to the material intended for use in the fabrication.




Retest If the test joint does not meet the requirements, the welder or welding operator, may at the discretion of COMPANY, carry out a new test joint of the same type as the one rejected. Failing of both these tests shall result in the welder or welding operator not being employed further on the work. The welder shall only be considered for requalification after 14 days provided proof is given of proper training of the welder over that period.

6.1.8

Welder Qualification Record A record of the welder’s qualification test, including a reference to the corresponding WPS number, the essential variables according to AWS D1.1 and the test results, shall be issued for each welder or welding operator for each test they pass. Not withstanding any other radiography requirements of codes or of this specification, the first five production welds completed by each welder shall be subjected to 100% testing by radiography or ultrasonic.

6.1.9

Period Of Effectiveness a)

b)

Welders and welding operators who will perform welds in the process/position combinations for which they were previously qualified need not requalify for those combinations if both of the following requirements are met : i)

VENDOR can show that the welder's performance has been monitored and proven satisfactory since the qualification test.

ii)

The welder certificate has been endorsed by a COMPANY recognised Certifying Authority at a date less than six months before construction starts.

During construction, VENDOR shall provide evidence indicated in a) above to COMPANY so that the welder certificates can be re-endorsed within six months of the previous endorsement date. Any certificate not endorsed every six months shall be considered invalid.

c)

A qualified welder or welding operator may, at the discretion of COMPANY, be required to requalify if inspection reveals that the repair work is 5% or more measured by weld length over a period of any one week.



7.0

PRODUCTION WELDING

7.1

General

7.2


a)

Preparation and welding of structural members shall be in accordance with the appropriate qualified welding procedure specifications. Manual electrodes, wires and flux shall be of the same type and manufacture as those used in the procedure qualification tests.

b)

A complete list with pertinent description of all welding equipment intended by the VENDOR to carry out the works shall be submitted to COMPANY for approval.

c)

No welding shall be carried out until the structure to be welded has been properly aligned (refer to Section 8.6).

WELDING SEQUENCE VENDOR shall develop welding sequences to control warping, creeping and the build-up of excessive internal stresses in the structure. The sequences shall be submitted to COMPANY for approval before the assembly of any components. VENDOR shall furnish the necessary supervision to ensure that the planned sequences are followed. Sequences shall include : a)

Welding procedure specification to be applied.

b)

Sequence of connections to be welded.

c)

Any differences from the specified welding procedures, such as areas of preheating, reinforcements, etc.

d)

Post weld heat treatment, heating and cooling rates.

e)

Number and location of welders at each stage of assembly.

f)

Tack welds and spacers used in the assembly of components.

7.3

Weld Preparations

7.3.1

Alignment a)

At Splices (butt welding) The offset at butt joints shall not exceed T/10 (where T is the thickness of the thinner material) or 6 mm, whichever is less. The offset in longitudinal seams shall not exceed T/10 or 3 mm, whichever is less. All offsets greater than 2 mm shall be given a 1:4 transition.

b)

At Welded Intersections The utmost attention shall be paid to good alignment of the structural parts on opposite sides of the through member.

7.3.2

Surface Cleaning Before Welding Surfaces to be welded shall be free from loose scales, slag, rust, grease, paint and any other foreign material.




Edge Preparation Preparation of weld edges by gas cutting shall, wherever practicable, be done with a mechanically guided torch. Edges shall be left free of slag and the cut surface shall be ground to a smooth uniform surface by removing approximately 0.5 mm of metal. After grinding, the weld edges shall be visually examined to ensure freedom from defects.

7.3.4

Cleaning During And After Welding In between welding passes and after welding is complete, weld surfaces and surrounding areas shall be thoroughly cleaned of all spatter and deposits.

7.4

Weld Execution

7.4.1

Welding Position And Progression a)

SMAW Welding Electrodes shall only be used in the position recommended by the manufacturer. Weld progression in vertical joints shall utilise the uphill method. For the 1G, 2G, 1F and 2 F positions, the maximum size of electrode allowed is 6.4 mm. For any other position, the maximum size of electrode shall be 5.0 mm. The capping passes shall always be done with a 4.0 mm maximum electrode.

b)

SAW Welding This shall be done in the flat 1G position and in the case that it is done on pipe, the pipe shall be mechanically rotated 1GR.

7.4.2

7.4.3

Size Of Welds a)

To obtain optimum toughness, a small bead multipass technique shall be used. The weave width for SMAW, i.e. maximum oscillation of the electrode, shall not exceed two and a half times the electrode diameter or 12 mm whichever is the least.

b)

The width of SAW beads shall not exceed six times the electrode diameter and the welding speed shall be 375 mm per minute minimum.

c)

Fillet welds shall be completed in three or more runs except for seal welds, which may be done in one run. Two run fillet welds are not permitted.

d)

COMPANY shall have the right to limit the thickness of each weld bead or pass when this exceeds those given in the weld procedure qualification test.

Intermittent Welding Stitch welding i.e. partial seal welds shall not be allowed unless otherwise approved by COMPANY. All seams (not seal welded) which are exposed to corrosion shall be sealed by approved sealant.

7.4.4

Seal Welds Where stress bearing welds are required by Contract Drawings to extend only partially around a member, including plates joining another member, a seal weld of 4 mm minimum fillet shall be applied continuously to the remainder, but note should be taken that a hardness of HV 325 maximum shall not be exceeded.




Tack Welds Bridge tacking is the preferred method to avoid the tack becoming part of the final weld. Wherever possible, tack welds shall be temporary and the welding shall be performed using the same procedures as required for the final weld. Tack welds shall not be less than 50mm in length nor be smaller than 6mm equivalent fillet welds in section and spaced so that shrinkage forces cannot cause cracking (See 7.5.2 (c) for preheat requirements). Tack welds shall be performed by qualified welders. NDT, either MP or DP, shall be carried out on the tack welds as per the relevant code i.e. AWS D1.1. Any surface breaking defect apparent after removal or feathering of tack welds is to be ground out and NDT repeated until a satisfactory surface is reported. When the tack weld is to form part of the completed weld, it shall be ground to a feather edge, non-destructively tested and completely fused with the root run. Tack welds, which are not to become part of the final weld, shall be removed by grinding, and the parent metal non-destructively tested.

7.4.6

7.4.7

Butt Welds a)

Design of the groove and performance of welding shall be in accordance with the approved WPS. However, in general, the groove shall be bevelled to give an included angle of not less than 60 degrees and shall be of the V or X type (single bevel or double bevel). The root opening shall not be less than 2 mm and not greater than 5 mm and the root face, if any, shall not be greater than 2 mm.

b)

Where access to both sides is possible, double bevel groove welds shall be used to minimise welding stresses and shrinkage effects.

c)

When different thicknesses are to be butt welded, a 1:4 taper shall be provided on the thicker member starting at the toe of the weld cap.

d)

At any joint, no butt weld shall be located such that an incoming member will result in a weld overlapping the butt weld.

Plate and Tubular, T or Y Joints Design of the groove and performance of welding shall be in accordance with the approved WPS. However, in general, Figure 3.9 of AWS D1.1 shall be used as a guide for all T-K-Y connections. The bevel shall preferably be feather edged and the root opening shall be 3 - 5mm or according to an approved procedure. Welding of minor members shall be a full penetration type weld and where fabrication method permits, welding from both sides shall be carried out.

7.4.8

Weld Compatibility All weld joints shall develop the mechanical properties specified for the steel being welded. Where different grades of steel are joined, the weld metal shall be matched to the lower strength steel. The procedure shall be such as to safeguard the mechanical properties of the higher strength member.

7.4.9

Weld Finish Welds shall be left as welded and not be doctored with a torch or by any mechanical means to change their appearance.




Weld Interruption Welding of each weld shall be a continuous operation, with the exception of manually welded root runs for submerged arc welding. In the case that welding must be discontinued, this shall not take place before at least half of the final weld thickness is achieved. The maximum time that a production weld will remain part welded is two days. The maximum number of heat cycles that will be used in a production weld shall be two. Slow cooling of the weld area shall be ensured. Before continuation of welding, the weld shall be inspected for cracks visually and by MPI.

7.4.11

Weather Protection Welding operations shall be prohibited when the ambient air temperature in the immediate vicinity of the weld site is below -18o C. Welding operations shall also be prohibited when surfaces to be welded, welding consumables or welding personnel are wet or are exposed to rain, snow, or are exposed to wind velocities exceeding five (5) miles per hour (2.235 M/sec). Shelters shall be provided at all times to give protection to the weld areas from wind, rain and moisture. Precautions required :-

7.4.12

a)

The weld surfaces shall be thoroughly dried by preheating (not above 300o C). Temperature control shall be carried out.

b)

If any fabrication is to be carried out in the vicinity of equipment already installed in connection with the Work, then, before such fabrication work commences, VENDOR shall provide adequate protection to prevent any damage from weld spatter, flame cutting droplets and the like. Such protection shall be subject to the approval of COMPANY.

Arc Strikes Arcs shall be struck only on fusion faces and contact of the electrodes or the non-insulated parts of the electrode holder with the assembly shall be avoided. Places where any stray arcs have accidentally occurred shall be subject to repair or rejection at the discretion of COMPANY. Where permission to repair arc strikes mechanically has been given, the procedure shall include, but not necessarily be limited to, the mechanical removal of the defective material, blending of the excavation, checking by MPI and confirmation that the thickness of the repaired material is within permitted tolerances.

7.5

Preheating and Interpass Temperatures

7.5.1

General a)

Preheating shall be carried out by electrical resistance induction equipment or with gas burners specifically made and shaped for this type of operation. Torches for flame cutting or gouging shall not be used.

b)

The preheating temperature shall be established to a distance of at least 75 mm on either side of the weld line and throughout the wall thickness prior to welding and be maintained over the full length of the weld joint until the weld is completed unless specifically agreed otherwise by COMPANY.

c)

The temperature measurement for preheating may be by thermocouples or temperature sensitive crayons, or a combination of both as may be appropriate for the type of joint being heated and the method of heating.



7.5.2


d)

At all joints where preheating is required, COMPANY shall subject the joint to temperature checks before welding commences.

e)

During welding particularly where preheat has been used and for high heat input processes, care shall be exercised to control the interpass temperature and in no event shall it exceed 300o C or as indicated in the WPS. The interpass temperature shall be monitored by means of thermocouples or thermo sticks or another approved method.

Temperature Requirements a)

Preheat and inter-pass temperatures and procedures shall be in accordance with ABS requirements and AWS D1.1 Section 5.6 or as indicated in the approved WPS.

b)

Preheat temperatures for lifting lugs or padeyes shall be 150o C minimum

c)

For tack welding where the tack becomes part of the main weld, the preheat temperature shall be 50o C higher than specified on the WPS with a maximum of 300o C.

d)

If the metal temperature is less than 10o C, a minimum preheat metal temperature of 38o C is required. Preheat shall be maintained during the mulitipass welding. If surface moisture has gathered on the steel, the weld joint shall be dried by preheating the surface to remove the moisture.

7.6

Stress Relieving - Post Weld Heat Treatment

7.6.1

General Where required by contract drawings or specifications, welded assemblies shall be stress relieved by heat treating. The stress – relief treatment shall conform to the requirements stipulated in AWS D1.1 Section 5.8

7.6.2

a)

VENDOR shall inform COMPANY prior to any PWHT operation so that the proposed format can be reviewed and inspected as a prerequisite for COMPANY approval to proceed with the PWHT operation.

b)

PWHT of nodes shall be carried out following complete assembly of the node.

c)

The requirements for PWHT shall be determined from the thickness of the thickest component of the welded assembly. For tapered sections, the thickness at the weld shall be taken as the base metal thickness.

d)

Assemblies with different maximum thickness (but not exceeding a ratio of 2 : 1) may be post-weld heat treated in the same furnace charge in accordance with the heat treatment requirements for the thickest assembly in the charge.

e)

Following PWHT, the temperature charts shall be marked with a clear identification and shall be retained for the quality control dossier. A copy shall be forwarded to COMPANY.

Requirements For PWHT PWHT is required when any of the following conditions apply: a)

PWHT is indicated on drawings.

b)

PWHT is indicated in the WPS.

c)

The base metal thickness exceeds 65 mm.




Method a)

Post-weld heat treatment shall be done in a suitable furnace or using proper induction or electrical resistance equipment.

b)

Where it is impracticable to heat the whole assembly in a furnace, VENDOR shall propose, in writing, an adequate method of PWHT for the approval of COMPANY. This procedure shall include the following information :-

c)

•

The number, dimensions, locations and method of attachment of heating elements

•

The location, type and thickness of insulation.

•

Thermocouple types and their calibration procedures.

•

Method of attachment of thermocouples, locations and number.

•

Types of temperature recorder and the calibration procedures.

•

Standard information to be recorded on the chart.

The procedure for PWHT shall comply with the following :An assembly may be heat treated in sections in an enclosed furnace, providing the overlap is at least 5SQRT(Rt) (R is the internal radius and t is the base metal thickness) with a maximum of 1500 mm. Where this method is used, the portion outside the furnace shall be insulated so that the longitudinal temperature gradient is such that the distance between the peak and half peak temperature is not less than 2.5SQRT(Rt) with a minimum of 750 mm. Circumferential seams in tubulars may be heat treated locally by electrically heating a shielded band around the entire circumference. The width of the heated band shall not be less than 5SQRT(Rt), the weld being in the centre. For plate the width of the band shall be 20t. Sufficient insulation shall be fitted to ensure that the temperature at the edge of the heated band is not less than half the peak temperature. The ends of the tubulars shall be covered to avoid draughts inside the tubular. In addition, the adjacent portion of the tubular outside the heated zone shall be thermally insulated such that the temperature gradient is in accordance with the above. A minimum total insulated bandwidth of 10SQRT(Rt) for tubulars, or 40t for plate, is recommended for the purpose of meeting this requirement. Welded attachments may be locally heat treated by electrically heating a shielded circumferential band around the entire surface. In such cases, the above requirements for circumferential seams in tubulars shall apply with the exception that the width of the circumferential band (2.5Rt minimum or 750mm for plate) shall be measured from the edge of the weld which connects the attachments to the main fabrication. Items or subassemblies to be post-weld heat treated shall be robust and adequately supported to prevent warping and damage. In cases where these requirements cannot be strictly applied, modifications may be agreed between VENDOR and COMPANY.



8.0

FABRICATION AND DELIVERY

8.1

General


Fabrication and delivery shall be in accordance with:

8.1.1

8.1.2

•

API RP2A Section 11

•

AISC "Specification for Structural Steel Buildings" - Chapter M

•

AISC "Code of Standard Practice for Steel Buildings and Bridges" - Section 6

•

ABS Rules (see Section 1.5.2)

Erection Loads and Stability a)

During site assembly, VENDOR shall take account of all temporary erection loads imposed on the structure from supports, jacking and slinging at each stage of the structure assembly.

b)

At each stage of the structure assembly, VENDOR shall take account of the local or overall stability from self weight and environmental loads; inclusive of scaffolding, staging, welding shelters and temporary works. VENDOR shall ensure that all stresses induced in the structure during fabrication and load out are within acceptable limits.

c)

VENDOR shall take due consideration of the effect of wind induced vortex shedding on the structure or parts of the structure during construction.

d)

VENDOR shall demonstrate to the satisfaction of COMPANY that he has considered all relevant erection and temporary loads.

e)

VENDOR shall produce a procedure for each erection or transport activity where the item under consideration exceeds 50 tonnes in weight, and at other times when requested by COMPANY. The procedure shall cover all aspects detailed in this Clause and shall satisfy the requirements of the regulatory authorities.

f)

VENDOR shall produce and maintain on a continuous basis a reliable weigh control report.

Material Identification a)

All components shall be clearly marked in accordance with the approved scheme for the identification of members, welds and welders.

b)

VENDOR shall maintain full identification of primary structural steel throughout fabrication and VENDOR’s reference number shall be die-stamped, using round nosed dies or by paint marking, on cut sections of plate, sections and tubulars, in a manner to be approved by COMPANY.

8.2

Material Preparation

8.2.1

Straightening All rolled plates, bars and sections shall be flattened and straightened and made free from twist, without damage, before marking and cutting. The limit on the amount of strain induced by cold working shall be 3%.




Cutting And Edge Preparation The steel shall be cut to size by thermal cutting or machining in accordance with approved procedures except that for plates less than 15 mm thick, cold shearing may be used, provided that the sheared edge is dressed back by machining or grinding for a distance of not less than 1.5mm. All cut edges shall be prepared to the satisfaction of COMPANY. The hardness of flame cut edges shall be limited to 325 HV 10 maximum either by controlled speed flame cutting, by preheat, or by grinding back or machining after cutting. The cut edges shall be 100% visually examined for laminations, cracks, and other defects. If such defects are detected, the extent shall be established. A repair procedure shall be agreed with COMPANY. At the discretion of COMPANY, the material component may be rejected. Where there is a steel location of the chord to brace the connection area shall be UT inspected to detect any defect such as lamination, etc. This is not applicable if the brace to chord connection is via gusset plates i.e. load transfer is principally by shear Any bevelled edge that has been damaged shall be restored to the minimum tolerances. Where such restoration involves welding, only welding procedures approved by COMPANY shall be used. Maximum buttering heights shall not exceed 8mm.

8.3

Stiffeners Stiffeners shall be fitted accurately and neatly between the flanges of beams, and where tight fits are required to transmit bearing, the ends of the stiffeners shall be milled or ground, as detailed on the Contract Drawings, to secure an even bearing against the flange faces, or shall be bevelled and fully butt welded to the flange. Cope holes shall be used only when indicated on the design drawings (see Section 8.6.4).

8.4

Splices

8.4.1

General

8.4.2

a)

Splices shall be kept to a minimum by making individual sections as large as possible consistent with the size of the steel supplied and VENDOR’s approved assembly sequence.

b)

Splices shall be arranged to minimise overhead welding. Spliced materials of different widths and thicknesses shall have smooth transitions as specified in Section 7.3.1.

c)

Lapped joints are not permitted.

d)

Unless specified otherwise on the drawings, when two or more members intersect or overlap at a joint, the order in which each member comes into the joint will be determined by wall thickness and/or diameter. The member with the thickest wall will be the continuous or through member, and the sequence for framing the remaining members shall be based on the order of decreasing wall thickness.

Beams Segments of beams with the same cross-section may be spliced. 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 one-half the cantilevered length. For beams employed in any span between supports, there shall be no splice in the middle one-fourth of the span. Splices shall not be located closer together than twice the depth of the beams, or 900 mm, whichever is larger.


DETAILED DESIGN FOR MUTINEER / EXETER FPSO TOPSIDES Specification for Structural Fabrication, Welding, Inspection and Testing 8.5


Camber When members require camber, the amount shall be specified and shown on the contact drawings, and the means of achieving the correct amount of camber shall be agreed with COMPANY.

8.6

Laying-Out, Alignment and Fit-Up

8.6.1

Laying-out

8.6.2

8.6.3

a)

At all stages during fabrication, VENDOR shall ensure correct positioning, alignment and levels in accordance with the required datum.

b)

During layout and assembly of each node, VENDOR shall permanently mark and identify all wrap lines, working points and centre lines.

c)

Overloading, damage or any permanent deformation of any of the structural components at any stage of the erection shall be rectified in accordance with a procedure approved by COMPANY.

d)

No structural welding shall commence until the members to be joined have been properly aligned and braced to prevent distortion.

Alignment And Fit-up For Welding And Tack Welding a)

Whenever practicable, clamps, holding devices or other setting up fixtures shall be used in assembling parts of the structure to avoid temporary welded attachments or tack welding. In fit-up where clamps cannot be used, temporary spacer strips shall be used to ensure the correct root gap prior to tack welding.

b)

Ring stiffeners, stiffeners and diaphragms shall be close fitted to the shape of the surface to which they are attached either by machining or by flame cutting and grinding.

c)

At intersections, the utmost attention shall be paid to good alignment of the structural parts where members meet on opposite sides of a through member. As-built dimensions shall be used to align such plates and not theoretical dimensions.

d)

Where powered manipulations are used in conjunction with Mechanised Welding Machines for the production of circumferential seams in tubulars, the tubular shall be set to turn at a constant angular velocity to ensure uniform deposit of weld metal.

Temporary Attachment Welds Temporary weld attachments and their removal shall meet the requirements of Section 8.7 below.

8.6.4

Cope Holes Cope holes for ring stiffeners, stiffeners and diaphragms shall be permitted to a maximum radius of 50 mm. The cut edges of the cope holes shall be ground smooth to remove all notches, prior too fit-up of the member(s). The fillet portions of all welds are to be returned through the cope hole. Cope holes shall be used only with the permission of COMPANY and may have to be filled to an approved method. Cope holes shall not be adopted where sealed/bunded areas are required for drainage purposes.




8.7

Temporary and Non-Structural Attachments and Cut-Outs

8.7.1

Welding Temporary and non-structural attachments shall be fitted to the shape of the surface to which they are attached, and welding shall be to a qualified and approved procedure by qualified welders. Temporary or non-structural attachments shall not be welded within 75 mm of any other structural weld measured from weld toe to weld toe. Locations and fixing details of all temporary attachments are subject to the prior approval of the COMPANY.

8.7.2

Removal The removal of temporary attachments shall be either by thermal cutting or by grinding. If thermal cutting is employed, the attachments shall be cut off at a minimum distance of 5mm from the surface of the material and then ground flush. Following removal, the area of the attachment weld shall be subjected to 100% magnetic particle inspection. Temporary attachments shall not be removed by hammering, or by any other technique, which may cause mechanical damage to the surface of the steel, forming the main structure. Following removal, any damaged area shall be ground to merge smoothly with the original surface, and the surface is to be magnetic particle inspected. Where gouges up to 20% of the steel member thickness have been made, then after grinding and testing they shall be repair welded to an approved procedure. Where gouges exceed 20% of the material thickness, the repair procedure or alternative solution shall be proposed by VENDOR and be subject to the approval of COMPANY.

8.7.3

Temporary Cut-Outs The need for temporary cut-outs shall be subject to approval by COMPANY in each instance unless they are detailed on the Contract Drawings. When temporary cut-outs are necessary, they shall be prepared with the same degree of care as for permanent cut-outs and shall be cut-out prior to erection of the member(s). Special care shall be taken to ensure that the weld preparation applied to the cut-out is appropriate to the final erected orientation of cut-out at the time of rewelding. The cut-out shall be trial fitted prior to erection of the member. An approved welding sequence developed such that welding will be minimized shall be followed. All cut-outs shall be prepared with radius corners not less than 50 mm.

8.8

Finishing of Surfaces a)

Prior to completion, VENDOR shall remove all burrs, tack welds and other marks made by welding, scaffolding or temporary bracing used in the fabrication procedures.

b)

Any plate defects resultant from handling or fabrication works shall be repaired mechanically or to an approved welding procedure in accordance with the requirements of this Specification. The method applied for plate repairs shall be subject to the approval by COMPANY.

c)

For areas with arc strikes see Section 7.4.12.



REPAIR AND REMEDIAL PROCEDURES

8.9.1

Welding Repairs


Weld repairs shall be carried out in accordance with an approved welding procedure. In the case of repairing cracks, the cause of cracking shall first be established satisfactorily before repair is allowed. When a welding defect has been identified, the following procedure shall be initiated: a) b)

c) d) e) f) g)

8.9.2

Any defect which requires repair, shall be brought to the immediate attention of the Company Representative. The removal of defective areas shall be by machining, grinding, or arc-air gouging followed by grinding. The resulting excavation shall be clean and have a contour to permit ease of repair welding. The complete removal of defects shall be confirmed by magnetic particle inspection. Repair welding shall be performed in accordance with the approved, qualified welding (or repair welding) procedure. Subsequent to repair, the repair area plus 100mm on either side shall be 100% retested. The NDT method(s) shall be as specified for the original weld. All repairs shall be fully identified and documented. Documents shall be made available to the Company Representative for review. The Vendor shall bear the cost of repairing and re-testing all defective welds.

Straightening Of Distorted Members a)

Prior to straightening of a distorted member, calculations of the strains involved shall be submitted to COMPANY for approval. Members may be straightened cold if the deformation does not exceed 3% strain.

b)

When carried out hot, the temperature of heated areas, measured by methods approved by COMPANY shall not exceed 600o C. The part to be heated shall be substantially free of stress and from external forces except those stresses imposed resulting from the mechanical straightening used in conjunction with the application of heat.

c)

Flame heating rectification shall be carried out only in accordance with approved procedures and with the agreement of COMPANY in each specific instance.

d)

Straightening procedures, which will include full details of methods of monitoring temperatures and times, are to be submitted to COMPANY for approval prior to any attempt being made at straightening. Methods of assessing the extent of any damage to the parent material by straightening are to be included in the proposals.

8.10

ANCILLARIES AND TEMPORARY WORKS

8.10.1

Material Selection Materials for ancillaries and temporary works, which are to be welded directly to the primary structure, shall meet the requirements as set for Type III secondary steel (refer to Project Documents No.: AP003164-G-JSD-1800-002 - "Structural Specification for Materials")



8.10.3


Temporary Fabrication Aids a)

Where possible, slings shall be wrapped around primary structural members for the purpose of lifting or rearing sections of the structure. Timber packers or other devices approved by COMPANY shall be used to prevent distortion and damage, particularly where slings pass over protrusions such as stubs, flange outstands, etc.

b)

Additional precautions shall be taken to ensure that miscellaneous projections such as pipes, pipe supports, nozzles, etc. are fully protected from interference with lifting slings during installation.

c)

Adequate safety factors shall be used to cater for the effects of variation in self weight, impact, dynamic effects and unequal sling lengths when determining lifting requirements.

d)

Proper account shall be taken of the effects of differential deformation of support points during lifting or jacking. Structural calculations to investigate both global and local member adequacy shall be carried out by VENDOR to prove the integrity of any lifting or jacking operation and shall be submitted to COMPANY for approval prior to execution of the operation.

e)

Care shall be taken that the paint work of the structure is not damaged.

Stairways And Ladders All components of stairways and ladders shall be fabricated to the dimensions shown in the Contract Drawings. All pipe ends shall be sealed. Safety cages to ladders shall not be provided unless indicated in the Contract Drawings. All stairways and ladders shall be of welded construction. On the rung of the ladders antislip ladder rung covers of the type “Safemate” industrial grade or equivalent as approved by COMPANY shall be installed. Small areas of galvanising damaged during erection shall be degreased and wire brushed to a clean metal finish and the area painted according to COMPANY approved painting scheme.

8.10.4

Bar Grating a)

All grating shall be serrated and be located and secured in accordance with the Contract Drawings. Fastening design shall include wave splash and construction forces.

b)

Clips, bolt, top washers and bosses shall be hot-dipped galvanised after completion of fabrication.

c)

All bar grating and installation pieces shall be cut to the required dimensions and installed as indicated in the Contract Drawings. Maximum dimensions of bar grating are envisaged to minimise joints. The bar grating which will not be installed prior to load-out shall be test fitted and given identification marks to ease installation offshore. All bar grating installed before load-out shall be secured to its supporting members, in accordance with the Contract Drawings. Small areas of galvanising damaged during erection are to be repaired. Damaged areas shall be cleaned of all traces of oil and grease by means of a solvent cleaner. The damaged areas of galvanising shall be wire brushed to a clean metal finish and the area repaired by painting according to Project document No.: AP003164-G-JSD2310-0001 - "Painting Specification".



8.10.6


Handrails And Safety Fencing a)

Tubular sections of handrailing consists of horizontal rails, vertical standards and associated sockets, clamps and bolts.

b)

All components of the handrail shall be fabricated to the dimensions shown in the Contract Drawings. All pipe ends shall be sealed. Kicker kerbs shall be provided if called for in the Contract Drawings. Handrails shall be of welded construction.

c)

Handrails shall be painted in accordance with Project Document No.: AP003164-GJSD-2310-0001 - "Painting Specification". Handrails shall be hot-dipped galvanised prior to application of paint. Bleed holes shall be sealed.

d)

Field installed handrails shall be trial fitted at fabrication site and properly identified.

Temporary Bracing And Supports a)

Scaffolding supports and facilities for supervision and inspection of the work shall be provided as necessary. They shall be sufficiently solid to prevent deformation.

b)

Adequate temporary bracing shall be provided and shall be left in position until such time as the structure is sufficiently far advanced for the bracing to be no longer required.

9.0

DIMENSIONAL CONTROL

9.1

General The general requirements for the dimensional control of the structure/s during fabrication are as follows : a)

Prior to the commencement of fabrication, the Vendor shall submit to the Company for review and approval, a proposed method of monitoring dimensions and tolerances.

b)

The Vendor shall provide personnel, equipment and instruments necessary to monitor and control dimensions and tolerances. All instruments used shall have current valid calibration certificates that are traceable to a Company approved standards system.

c)

Tolerances shall be based on the theoretical work points and centre-lines of the structures, referenced to a permanent axis system as stipulated in the contract drawings.

d)

All structural elements shall be surveyed at the fit up stage and any discrepancies rectified prior to the commencement of welding.

e)

The Vendor shall assemble the structure/s to within the acceptable tolerances. Where no appropriate tolerance is provided in the contact drawings and/or codes (see Section 9.2), values shall be obtained directly from the COMPANY.

f)

Tolerances shall be checked at every stage and the final survey shall meet the defined tolerances. The final survey shall be on complete sections and on the completed structure, after post weld heat treatment if applicable, and shall be carried out by VENDOR.



9.2


g)

All setting out and fit-ups shall be subject to an appropriate tolerance. Where no appropriate tolerance is stated in the contract drawings and/or codes (see Section 9.2), then the tolerance shall be obtained from COMPANY.

h)

COMPANY shall reserve the right to employ independent dimensional control sources as a crosscheck whenever considered necessary throughout the fabrication program.

i)

No forcing or constraining of components shall be undertaken to obtain the required tolerance without the approval of COMPANY.

j)

Fabrication and yard assembly supports shall be set to the appropriate level shown on VENDOR’s approved setting-out drawings to within ± 3mm. Where no such drawings exist fabrication shall be carried out from a level plane to within ± 3mm.

k)

Where there is settlement of supports outside the tolerances given above this shall be immediately reported to COMPANY. Such settlement shall be corrected by shimming if in the opinion of COMPANY such settlement will cause local overstressing, permanent deformation or lead to fit-up problems.

Tolerances for Structural Components and Sub-Assemblies If not specifically stated in the contract drawings each member of the structure shall be located accurately to the final fabrication tolerances given in: •

Section 11.1.5 of API-RP-2A (Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms)

•

API 2B (Specification for the Fabrication of Structural Steel Pipe)

•

AISC (Code of Standard Practice for Steel Buildings and Bridges) – Section 6

•

AWS D1.1 (Structural Welding Code - Steel)

•

ABS Rules (see Section 1.5.2)



10.0

INSPECTION AND TESTING

10.1

General

10.2


a)

COMPANY shall have the right to inspect the fabrication and erection of all items covered by this Specification. Any weld defects, damage due to lift up, arc strikes or other weld features, which COMPANY specified as deficient or detrimental to the integrity of the structure, shall not be acceptable.

b)

Inspection personnel shall have free access at all times to any part of VENDOR’s, or his sub-contractor’s yard and facilities that are concerned with the Works. They shall be shown full cooperation and allowed sufficient time for all inspection and testing procedures to be properly executed. VENDOR shall carry out all necessary cleaning of the area necessary to facilitate inspection and testing.

c)

As far as possible, no testing shall be carried out within 48 hours of completion of welding.

d)

VENDOR shall furnish, install and maintain in safe operating condition all scaffolding, ladders, walkways, adequate lighting, etc, necessary for safe and thorough inspection. This equipment must conform with local industrial specification and safety codes.

e)

COMPANY reserves the right to retest and reject any and all NDT personnel at anytime. COMPANY will be responsible for the cost of removing and replacing samples found not to be defective as retesting specified additionally by COMPANY.

f)

VENDOR shall inform COMPANY at least 48 hours prior to any work such as assembling or fabrication of any section, grit blasting or painting to enable COMPANY and its Representative to adequately arrange any inspection and testing deemed necessary.

g)

Whenever any piece is to be assembled that will prevent subsequent inspection of an area, COMPANY shall be so notified such that the said area can be inspected and any defects corrected before proceeding with the assembly.

h)

When required by the Contract documents, VENDOR shall provide on site complete facilities for radiography, ultrasonic and magnetic particle inspection of welds including equipment for developing and viewing films and the full time service of qualified technicians conversant with radiographic and ultrasonic inspection techniques.

i)

Any inspection by COMPANY or by the verification party shall not absolve VENDOR from his responsibility to exercise such quality assurance procedures as will ensure that the requirements and intent of this Specification are satisfied.

j)

Final acceptance of Post Weld Heat Treated (PWHT) joints shall be done after PWHT.

Inspection Requirements The Vendor shall implement an Inspection and Test Plan to ensure compliance with the workmanship requirements of ABS, AWS D1.1, the Contract Drawings and this Specification. The Vendor shall submit the proposed plan to the Company for approval prior to the commencement of fabrication. The cost of carrying out all inspection (excluding the Company appointed Inspector/Certifying Authority) and testing shall be borne by the Vendor.



Extent of Inspection

10.3.1

Fabrication Classes


Components and sub-assemblies of the construction are distributed into the following fabrication classes : Class 1 : Failure of any of these members either causes total or partial destruction of the platform during its service, or destruction of portion of it during their installation, or they are components that cannot be repaired. Class 2 : Failure of any of these members causes platform shut-down, but without inducing total or partial destruction of the platform. Repairs of these members can only be made if installation or production of the platform is stopped. Class 3 : These are members other than those classified in class 1 or class 2. Class 4 : These are Non Structural components or tertiary structures. 10.3.2

Extent of Non-Destructive Testing Unless noted otherwise on the contract drawings, all fabrication welds completed in accordance with this Specification shall be non-destructively tested in accordance with the minimum requirements specified in Table 10.3.2 below: Unless otherwise agreed upon by COMPANY and the VENDOR, the percentages of weld inspections shall be understood as follows: •

For welds above 2 metre long, the percentages of welds to be inspected shall mean the thorough inspection of the stated percentage of all welded connections of a given type ie. a 20% check means inspection of 20% of the length of each welded connection in the category concerned and not 100% inspection of 20% of the connections.

•

On the contrary, for Welds not exceeding 2 metres in length, 100% inspection is normally to be carried out on the stated percentage of the connections of the given type. If partial checking of welds reveals that a particular weld appears defective the entire weld shall be examined and the partial checking of all other welds made by the same welder or procedure since the last partial check will be extended as specified below.

Retest

Retest

Retest

Initial Test

Class 1

Class 2

Class 3

Spot

100%

20%

10%

5%

100%

20%

10%

10%

100%

50%

20%

20%

100%

100%

50%




If any of these welds are defective then the retesting is extended to 100% whatever the member classification. Consequently, the level of inspection of the future welds of this type may be increased at the discretion of the Inspector, until satisfactory results are obtained. As a general rule, initial inspection shall be 100% until a satisfactory level of quality has been verified. Non-Destructive Testing (N.D.T.) shall be carried out especially on intersection of butt welds, cruciform joints, as well as on start and stop points of automatically welded seams. Areas which have been strained in the through thickness direction by welding will be ultrasonically tested for lamellar tearing. The Inspector shall have the right to select the welds or part of the welds to be inspected. When Gas Metal Arc Welding (G.M.A.W) is used, Ultrasonic and Magnetic Particle testing may be required by Inspector on a spot basis in addition to Radiographic Testing. If difficulty is experienced in categorising defects revealed by ultrasonic testing, radiography shall also be used to facilitate interpretation, or vice versa. At the discretion of the Inspector supplementary radiography, or substitution of radiography in lieu of ultrasonic testing, shall be used to confirm the ability of ultrasonic testing to detect and evaluate correctly defects such as root concavity and linear porosity and other root defects in single sided groove welds. When either radiography or ultrasonic testing are used as a check or a substitution for the other technique, the acceptance criteria applied shall be as defined for the actual technique used, unless the Inspector requires otherwise.




TABLE 10.3.2 : EXTENT OF NON DESTRUCTIVE TESTING Steel Type and Member Classification (1)

Type of Connection

Visual Inspection

Radiography (8)

Ultrasonics (7)

Magnetic Particle (3)

Class 1

Butt Welds

100%

-

-

20% (4)

100% (10)

-

100% (5)

Type II Steel Primary with TTP

T-joints

20% (4) -

100% (2)

100% (5)

-

-

100%

10%

-

-

100% (9)

-

20% (5)

T-joints

-

20% (2)

20% (5)

Fillet Welds

-

-

20% (5)

5%

-

5% (5)

Fillet Welds Class 2

Butt Welds

100%

Type I Steel Primary

Class 3

Butt Welds

100%

Type III Steel

T-joints

-

Spot (2) (6)

5% (5)

Secondary

Fillet Welds

-

-

5% (5)

Class 4

All Welds

(11)

-

(12)

100%

Type III Steel Tertiary




NOTES on table above: (1) Classification of members is defined in clause 10.3.1 of this Specification. Welds connecting members of different categories of importance shall be subject to the requirements of the most stringent class. (2) Applies to all welds (such as T or Y-joints, tubular joints) other than Butt Weld shaving full penetration, or partial penetration with weld metal cross-section exceeding 12.7 mm. (3) Magnetic Particle Testing may be replaced by Liquid Penetrant Testing with prior approval of Inspector. (4) Applies to welds performed on Mild Steels and subject to static load only. (5) Applies to welds subject to dynamic load or welds performed on High Strength Steels (Type I or Type II) (6) “Spot” means 0 to 5% at the Inspector’s discretion. (7) Ultrasonic Testing applies when material thickness is more than 12.7 mm. Ultrasonic may be replaced by radiography where wall thickness is less than or equal to 35 mm. (8) Radiography is normally replaced by ultrasonic for thicknesses > 35 mm. Radiography applies by priority to intersections of butt welds and to start and stop points of automatically welded seams. (9) 100% extent for radiography (WT ≤ 35 mm) or ultrasonic (WT > 35 mm) of : i. flanges of beams and columns ii. circular welds of tubulars iii. 10% for other connections. (10) Butt Welds on materials, which comply with the following conditions all together may be required by the Inspector to be, inspected 90% radiography +10% ultrasonic (instead of 100% radiography) :

(11)

i.

Specified Yield Strength > 295 MPa,

ii.

I.I.W. Carbon Equivalent > 0.41% (ladle),

iii.

Wall Thickness > 25.4 mm (1”).

Extent of radiography (when necessary) as stated in the Particular Specification.

(12) Magnetic Particle to 100% extent only when welding on semi-hard or hard steels and alloy steels liable to quenching under welding operation (for instance welding of bearing plates). Purpose of inspection mainly to ensure freedom of cracks, excessive undercuts or other injurious notch defects. (13) Where steel plate thickness exceeds 20mm, the Vendor, subject to approval by the Company, may elect to substitute UT for RT inspection. (14) Where RT is selected for all welds of a particular type, some UT may be prescribed by the Company or Certifying Authority to confirm that all significant defects are being detected. Similarly, UT procedures may be checked by some RT where nominated by the Company or Certifying Authority. In the event that the preferred method is found to be deficient, the procedure shall be revised and resubmitted for approval. Welds already examined shall be re-examined with the revised procedure. (15)

Butt welds include T butt welds and corner welds.




(16) All repair welds shall be 100% inspected after completion by the methods appropriate to the material and joint type as required by this specification. (17) If defective welds are found in areas of the structure requiring less than 100% testing, the Vendor shall increase the test requirements in such areas to 100% coverage, at no additional cost to the Company. (18) The required percentage of welds to be inspected shall mean the thorough inspection of the stated percentage of all welded connections of a given type and shall not mean the inspection of the stated percentage of the total length. (19) During fabrication, the non-destructive testing of a completed weld shall be performed prior to commencing any further work in the vicinity of the connection. The Vendor shall schedule his work in such a manner as to permit this. (20) Inspection of completed welds is to be performed no sooner than 48 hours following the deposition of the final weld pass. 10.4

Padeye Testing and Marking All padeyes shall be hard-stamped with the WLL. Padeyes where specified on the drawings shall be load tested to 1.1 x WLL to provide a test matching the as lifted requirements to Company approval. Proof load testing shall be carried out using load cells with current certificates of calibration that are traceable to a company approved standard



11.0


FIELD INSTALLED ITEMS Field installed sections of gratings and handrails shall be adequately marked (tagged) and a placement drawing prepared by VENDOR to show uniquely where each section of grating or handrail has to be placed. This shall also apply to all other structural items to be field installed.



12.0

ADDITIONAL REQUIREMENTS

12.1

Painting


VENDOR shall present modules in a location, orientation, position and shelter suitable for performing blasting, cleaning and painting in accordance with Project Document No.: AP003164-G-JSD-2310-0001 – “Painting Specification”. 12.2

Pre-Commissioning VENDOR shall present modules in a location, orientation, position and shelter suitable for the modules to be appropriately and conveniently fitted-out with all the necessary equipment, piping, E&I, and bulks ready for the pre-commissioning phase.

12.3

Final Weighing & COG Determination Before fabrication commences the VENDOR shall submit to the COMPANY, for review and approval, a weighing procedure for the completed modules, including COG determination. Prior to loadout the VENDOR shall weigh and determine the COG for each module in accordance with this COMPANY approved weighing procedure. The COMPANY Representative shall witness all weighing and there shall be no variance to procedures and equipment used (including instrumentation) for any weight test.

12.4

Loadout Modules shall be fabricated by VENDOR in a location, orientation and position as agreed with COMPANY to facilitate loadout by COMPANY advised method.


W1440-P4-S-0030_1 Specification for Structural Fabrication, Welding, Inspection & Testing

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