T-MCE-STD-001 Rev 0 - Welding and Inspection of Process and Utility Pipework Vessels and Equipment...

TECHNICAL SPECIFICATION

WELDING AND INSPECTION OF PROCESS ANDUTILITY PIPEWORK, VESSELS AND EQUIPMENT

AT LAND AND OFFSHORE FACILITIES

Issue Date By I,) Cfieckea ApprovedEng. By: UIE/P/SDDLocation: UIE

Revised from DEP 31.38.01.31-UIEDescription

II

Shell UpstreamInternational Europe

Sheet: 1 of 59Doc No.: T-MCE-STD-001

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Eng. By: UIE/P/SDD Location: UIE

Shell Upstream International Europe

Sheet: 2 of 59 Doc No.: T-MCE-STD-001

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TABLE OF CONTENTS 1. INTRODUCTION 41.1. SCOPE 41.2. PRECEDENCE OF DOCUMENTS 41.3. DEFINITIONS 41.4. ABBREVIATIONS/ACRONYM 51.5. REFERENCE DOCUMENTS 61.6. QUALITY CONFORMANCE 81.7. DEVIATIONS 82. GENERAL 92.1. MATERIALS 92.2. PROCESSES 92.3. WELDING CONSUMABLES 102.3.1. General 102.3.2. Consumable Certification 102.3.3. Consumable Handling/Storage 103. GENERAL REQUIREMENTS 123.1. WELDING PROCEDURES 123.1.1. Qualified Procedures 123.1.2. Procedures to be Qualified 123.1.3. Essential Variables 123.1.4. Welding Procedure Qualification Testing 133.1.5. Repair Welding Procedures 153.2. WELDER QUALIFICATION 163.2.1. General 163.2.2. Pre-Qualification 163.2.3. Documentation 163.2.4. Time Limitations 173.2.5. Tube-to-tubesheet welding 173.3. WELDING - GENERAL REQUIREMENTS 173.3.1. Shop/Site Conditions 173.3.2. Equipment 183.3.3. Preparation for Welding 183.3.4. Weld Execution 203.3.5. Preheat Temperature Requirements 213.3.6. Interruption of Welding 223.3.7. Arc Strikes 223.3.8. Weld Finish 223.3.9. Post-Weld Heat Treatment 223.4. WELD INSPECTION 253.4.1. General Requirements 253.4.2. Visual Inspection 253.4.3. Magnetic Particle Inspection 253.4.4. Liquid Penetrant Testing 263.4.5. Radiographic Examination 263.4.6. Ultrasonic Examination 263.4.7. Inspection Personnel 263.4.8. Extent of Inspection of Process Piping Production Welding 273.4.9. Acceptance Specifications 273.4.10. Reporting 273.5. REPAIRS 273.5.1. General 273.5.2. Defect Removal 283.5.3. Root Repairs 283.5.4. Re-welding 283.5.5. Non-Destructive Testing 284. MATERIAL-SPECIFIC ADDITIONAL REQUIREMENTS 294.0.1. General Requirements 29




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4.0.2. PQR Requirements 294.0.3. PQR Testing Requirements 294.0.4. Essential Variables 294.0.5. Production Controls 294.1. NON-IMPACT TESTED CMN STEELS 314.2. IMPACT TESTED CMN STEELS (LTCS) 324.3. 3.5% NICKEL STEELS 334.4. LOW ALLOY STEELS 344.5. AUSTENITIC STAINLESS STEELS 354.6. 6% MO AND OTHER SUPERAUSTENITIC STAINLESS STEELS 364.7. DUPLEX STAINLESS STEELS 374.8. NICKEL ALLOYS 394.9. COPPER ALLOYS 404.10. TITANIUM 41FIGURES 42TABLES 46 APPENDICES APPENDIX A REPORTING REQUIREMENTS FOR WPQR 52APPENDIX B MINIMUM NDE REPORTING REQUIREMENTS 54APPENDIX C RECOMMENDED PRACTICE FOR DETERMINING VOLUME FRACTION OF

FERRITE IN DUPLEX STAINLESS STEEL WELDMENTS BY SYSTEMATIC POINT COUNT S 55

APPENDIX D WPQR/WPS COMPLIANCE WITH NORSOK M-601 59




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1. INTRODUCTION 1.1. SCOPE This document specifies the minimum requirements for the Welding and Weld Inspection of Process and Utility Vessels, Piping and associated Equipment for all facilities in UIE. It replaces DEP 31.38.01.31-UIE (March 2011). Existing procedures qualified to DEP 31.38.01.31-UIE, or its predecessor ES/124 Part 1 may be accepted, subject to review by the Principal. Note that, whenever reference is made to or compliance required with an international industry standard, a DEP or a technical specification, then the corresponding international industry standard, DEP and technical specification shall also apply. It is written in recognition of the latest regulations in force within the European Union including the European Pressure Equipment Directive (PED) 97/23/EC and refers to a list of harmonised Standards covering all aspects of the design and fabrication of pressure equipment. This Standard is based on these harmonised Standards, but recognises and builds on the expertise and good practice developed in previous Shell Specifications. References are also made to ASME B31.3, in conjunction with Shell DEP.30.10.02.31-Gen, with regard to PWHT requirements. For each welding procedure specification the Contractor is responsible for selection of welding consumables, welding processes, and welding operators, and obtaining approval for their use from the Principal. Responsibility for compliance with local/regional legislative requirements, e.g. NORSOK M-601 or Stoomwezen Rules for Pressure Vessels, and required approvals remain with the Contractor, though guidance on compliance with NORSOK M-601 is given in appendix D. When referenced standards are revised or superseded, then it should be assumed that the latest revision or superseding standard applies unless a specific revision is referenced. Final acceptance of fabrications is dependent upon acceptance of Contractors reporting and recording of production welding and its monitoring and welding inspection activities. The following work scopes are not included: Equipment within pipeline design scope, i.e. Risers, pipelines, and associated topsides pipe

fabrication, and subsea manifold pipework and tie-ins Large bore low pressure ducting, less than 0.5 bar gauge. Domestic pipework. 1.2. PRECEDENCE OF DOCUMENTS In the case of conflict between documents the following hierarchy of documents shall apply: First level Statutory laws and regulations Second level This Technical Specification Third level Cross-referenced documents Fourth level International codes and standards Any apparent conflict between the requirements of this Technical Specification and any other relevant document shall be notified to the Principal for clarification purposes. 1.3. DEFINITIONS Within this Standard, the following terms shall be applicable: Principal The Principal is the party that initiates the project and ultimately pays for it.

The Principal may also include an agent or consultant authorised to act for, and on behalf of, the Principal.




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Contractor The Contractor is the party that carries out all or part of the design, engineering, procurement, construction, commissioning or management of a project or operation of a facility. The Principal may undertake all or part of the duties of the Contractor.

Sub-Contractor A company awarded a contract by a Contractor to do part of the work awarded to the Contractor by the Principal. The work of the Sub-Contractor is carried out under the direction and control of the Contractor. Under its model contracts the Principal maintains the right to review all proposed Sub-Contractors, and sub-contracts.

Manufacturer / Supplier

The Manufacturer/Supplier is the party that manufactures or supplies equipment and services to perform the duties specified by the Contractor.

Shall The word shall indicates a requirement. Should The word should indicates a recommendation. 1.4. ABBREVIATIONS/ACRONYM The following abbreviations or acronym shall denote: WPS Welding Procedure Specification WPQR Welding Procedure Qualification Record SMAW Shielded metal arc welding GTAW Gas Tungsten Arc Welding GMAW Gas Metal Arc Welding SAW Submerged arc welding FCAW Flux Cored Arc welding T Nominal pipe wall thickness OD Outside Diameter ID Internal Diameter B Maximum nominal pipe wall thickness for As-Welded application HAZ Heat Affected Zone PWHT Post weld heat treatment C The chemical element Carbon CMn carbon manganese CTOD Crack Tip Opening Displacement ECA Engineering Critical Assessment AWS American Welding Society ANSI American National Specifications Institute ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials NDE Non-destructive examination MT Magnetic particle inspection PT Liquid Penetrant Examination RT Radiographic Testing UT Ultrasonic Testing VT Visual Testing DWDI Double Wall, Double Image DWSI Double Wall, Single Image FSH Full Screen Height IQI Image Quality Indicator SDH Side Drilled Hole FBH Flat Bottom Hole SENT Single Edge Notch Test SWSI Single Wall, Single Image CSWIP Certification Scheme for Weld Inspection Personnel PCN Personnel Certification in Non-Destructive Testing SNT Society for Non-Destructive Testing




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1.5. REFERENCE DOCUMENTS ASME B&PV Code Section II - Materials Part C Specifications for Welding Rods,

Electrodes and Filler Metals. ASME B&PV Code Section V - Non-destructive Examination. ASME B&PV Code Section VIII-Rules for Construction of Pressure Vessels Division 1. ASME B&PV Code Section IX-Welding and Brazing Qualifications. ASME B31.3 Process Piping. ASTM A370 Specification Test Methods and Definitions for Mechanical Testing of

Steel Products of Steel Products. ASTM A923 Standard Test Methods for Detecting Detrimental Intermetallic Phase

in Duplex Austenitic/Ferritic Stainless Steels ASTM E562 Standard Test Method for Determining Volume Fraction by Systematic

Manual Point Count BS 7910 Guide on Methods for Assessing the Acceptability of Flaws in Fusion

Welded Structures. CSWIP-WI-6-92 Requirements for the Certification of Welding Inspectors and Senior

Welding Inspectors DEP 30.10.02.31-Gen Shell Design and Engineering Practice: Metallic Materials Prevention

of Brittle Fracture DEP 31.38.01.31-Gen Shop and Field Fabrication of Piping DEP 39.01.10.11-Gen Selection of materials for life cycle performance (Upstream facilities) -

Materials selection process EN ISO 6892-1 Metallic materials Tensile testing Part 1: Method of test at ambient

temperature EN ISO 6892-2 Metallic materials Tensile testing Part 2: Method of test at elevated

temperature EN ISO 148-1 Metallic materials - Charpy pendulum impact test Part 1: Test method EN 1011-1 Welding. Recommendations for welding of metallic materials. General

guidance for arc welding. EN 1011-2 Welding. Recommendations for welding of metallic materials. Arc

welding of ferritic steels. EN 10204 Metallic products Types of inspection documents. EN 1321 Destructive tests on welds in metallic materials macroscopic and

microscopic examination of welds. EN 1418 Welding personnel Approval testing of welding operators for fusion

welding and resistance weld setters for fully mechanised and automatic welding of metallic materials

EN 1435 Non-destructive examination of welds. Radiographic examination of welded joints

EN 287-1 Qualification test of welders Fusion welding Part 1: Steels EN 439 Welding consumables shielding gases for arc welding and cutting. EN 473 Non-destructive testing. Qualification and certification of NDE

personnel. General principles EN 760 Welding consumables fluxes for submerged arc welding. EN 50504 Validation of arc welding equipment ISO 3690:2001 Welding and allied processes. Determination of hydrogen content in

ferritic steel arc weld metal. ISO 3834-2 Quality requirements for fusion welding of metallic materials Part 2:

Comprehensive quality requirements ISO 5172 Gas welding equipment Blowpipes for gas welding, heating and

cutting. ISO 6507-1 Metallic materials. Vickers hardness test. Test method.




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ISO 6508-1 Metallic materials. Rockwell hardness test. Test method (scales A, B, C, D, E, F, G, H, K, N, T)

ISO 6520-1 Welding and allied processes Classification of geometric imperfections in metallic materials Part 1: Fusion welding

ISO 9000 Quality management systems - Fundamentals and vocabulary. ISO 9606-1 Approval testing of welders Fusion welding Part 1: Steels ISO 9606-3 Approval testing of welders Fusion welding Part 3: Copper and

copper alloys ISO 9606-4 Approval testing of welders Fusion welding Part 4: Nickel and

nickel alloys ISO 9606-5 Approval testing of welders Fusion welding Part 5: Titanium and

titanium alloys, zirconium and zirconium alloys ISO 14731 Welding coordination Tasks and responsibilities ISO 15609 Specification and qualification of welding procedures for metallic

materials ISO 15614-1 Specification and qualification of welding procedures for metallic

materials Welding procedure test Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys

ISO 15614-2 Specification and qualification of welding procedures for metallic materials - Welding procedure test - Part 2 : arc welding of aluminium and its alloys

ISO 15614-3 Specification and qualification of welding procedures for metallic materials - Welding procedure test - Part 3 : fusion welding of non-alloyed and low alloyed cast irons

ISO 15614-4 Specification and qualification of welding procedures for metallic materials - Welding procedure test - Part 4 : finishing welding of aluminium castings

ISO 15614-5 Specification and qualification of welding procedures for metallic materials Welding procedure test Part 5: Arc welding of titanium, zirconium and their alloys

ISO 15614-6 Specification and qualification of welding procedures for metallic materials - Welding procedure test - Part 6 : arc and gas welding of copper and its alloys

ISO 15614-7 Specification and qualification of welding procedures for metallic materials - Welding procedure test - Part 7: Overlay welding

ISO 15156 Materials for Use in H2S-containing Environments in Oil and Gas Production - Parts 1, 2 and 3

ISO 17020 General criteria for the operation of various types of bodies performing inspection

ISO 17025 General requirements for the competence of testing and calibrating laboratories

NORSOK M-601 Welding and inspection of piping




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1.6. QUALITY CONFORMANCE The Contractor shall demonstrate to the satisfaction of the Principal that his activities within the scope of this document are in accordance with the relevant clauses from ISO 3834-2 and EN ISO 9000. The Contractor shall submit to the Principal for review and approval, a Quality Plan and procedural Specifications prior to commencement of work. Review of this documentation by the Principal shall only indicate a general acceptance and shall not relieve the Contractor of his obligations to comply with the requirements of the Contract. 1.7. DEVIATIONS There shall be no deviation from or addition to this Standard and pertaining documents without a specific written approval from the Principal. All conflicts between the requirements of this Standard and other relevant documents shall be referred to the Principal for resolution.




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2. GENERAL 2.1. MATERIALS All materials used for qualification of welding procedure specification, as defined by this Standard, shall be representative of materials to be used in production. They shall be supplied to a recognised national manufacturing specification and certified in accordance with EN10204, inspection certificate 3.1. as a minimum This certification shall verify that all appropriate inspections have been carried out, materials can be traceable to specific chemical analysis/mechanical properties and that material is technically consistent with the design requirements of this Standard. Specific requirements for each material group are shown in the relevant section for material types included in this Standard. Other non-specified materials shall comply with industry standards plus any bespoke design requirements as advised by purchase order. 2.2. PROCESSES All welding shall be performed with one of the following processes within the restrictions of this Standard unless an alternative is approved by the Principal. Process Description ASME EN/ISO

Gas Tungsten Arc Welding (a) GTAW 141

Shielded Metal Arc Welding SMAW 111

Gas Shielded Flux Cored Arc Welding (a) (GS)FCAW 136

Self-Shielded Flux Cored Arc Welding (SS)FCAW 114

Submerged Arc Welding - Solid Wire (b) SAW 121

Submerged Arc Welding - Cored Wire (b) SAW 125

Plasma Arc Welding (a) PAW 15

Gas Metal Arc Welding (active gas) (a) ,(c) GMAW 135

Metal-Cored Arc Welding (active gas) (a) ,(c) MCAW 138 (a) Gas shielded processes (GTAW, GSFCAW, GMAW, MCAW, PAW) shall only be used on site with adequate

weather shielding, as approved by the Principal. (b) Only fully mechanised SAW systems are permitted. (c) GMAW or MCAW welding may be allowed if the Contractor can demonstrate to the Principals satisfaction,

experience and control over the process and the continued competence of his welders. Unless otherwise approved by the Principal, the root and second pass of all single-sided welds shall be made using GTAW (or PAW in the case of austenitic stainless steel). All GTAW machines shall be equipped with arc starting devices, e.g. high frequency starting unit, crater-eliminating slope out control, etc. If local regulations or interference considerations do not permit these, alternative proposals shall be submitted to the Principal for approval. Whilst it is generally undesirable to change the type of tungsten electrode used for GTAW from that qualified, this change shall not be considered an essential variable when made for health and safety reasons (eg. a move away from thoriated tungstens) provided that there are no other significant process changes. Where thoriated tungsten electrodes continue to be used, automated sharpeners with dust removal facilities shall be used, along with an approved removal procedure. The permitted application of these processes is detailed in the relevant material section of this Standard.




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2.3. WELDING CONSUMABLES 2.3.1. General Consumables shall be supplied by a manufacturer accredited to ISO 9002 or an equivalent quality Specification approved by the Principal. Additionally, welding consumables shall be approved by one of the following organisations:

Controlas Lloyds Register of Shipping American Bureau of Shipping Det Norske Veritas Bureau Veritas

Their selection shall be approved by the Principal prior to procedure qualification. Their use shall be supported by manufacturer recommendation and verified performance data. As a minimum all welding consumables used in fabrication shall be selected to produce welds with mechanical properties fulfilling those specified for the base metal and this Standard. When alternative consumables are required, e.g. when improved corrosion resistance is necessary, then these will be specified by the Principal prior to procedure qualification. Filler metals proposed for use in dissimilar base metal combinations shall be agreed upon with the Principal for each specific design case. All consumables shall be identified on the WPS by their AWS or ISO classification along with the manufacturers name and designation. Reference by AWS or ISO classification alone may be acceptable to the Principal for certain types of solid wire consumables (eg. GTAW 316L wire). 2.3.2. Consumable Certification Welding consumables shall be delivered in accordance with their product data sheet and shall have certification (including chemical analysis) according to EN 10204, Type 3.1, as a minimum. Each consumable, or consumable batch, shall have individual marking relative to its certification. Batch testing of the welding consumables is also acceptable. In such case welding and testing shall be carried out in accordance with a typical welding procedure specification and certification presented in the format of a WPQR. Production material or an equivalent parent metal specification shall be used for such product certification. Fluxes for submerged arc welding processes shall be delivered with certification according to EN 10204, Type 2.2 as a minimum. 2.3.3. Consumable Handling/Storage Stored items shall be clearly identified with brand name, classification and batch number. Each batch of flux and wire shall be labelled with the information from the supply container. All bottles containing shielding gases shall have clear identification labels. Consumable handling shall be controlled by a procedure approved by the Principal. Storage shall be in accordance with the manufacturers recommendations for the consumable type. Electrodes and fluxes shall be supplied in moisture resistant sealed containers and stored in controlled environment as recommended by the supplier. Wire spools for automatic and semi-automatic processes shall be stored in original packaging preferably in cabinets. Flux shall be supplied and stored in accordance with manufacturers instructions.




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All non-identified, damaged, wet, partially used, rusty or otherwise contaminated consumables shall be discarded. Low hydrogen electrodes shall not be stored in heated cabinets containing electrodes of other types, such as rutile or organic type electrodes. Records of consumables shall be maintained to ensure an auditable trail from receipt, through pre-treatment, their issue to operators and return to stores so that their identity can be verified at any stage. SAW fluxes shall not be left in machine hoppers for extended periods, when welding is not being carried out, e.g. overnight or during non-productive shifts. Recycling of flux shall only be allowed if the procedure is endorsed by the consumable manufacturer and by the Principal. GTAW wires shall be cleaned with a solvent immediately prior to their use. Wire for automatic or semi-automatic welding, remaining from a partly used coil or spool, may be reused as new wire if it is promptly repackaged after use in new sealed containers and stored as a new consumable. GSFCAW wires shall be returned to a controlled storage area at the end of each shift. This requirement may be waived for seamless copper-coated wires that are fully enclosed in the wire feeder. Bare filler wire in coils or spools that has not been kept in sealed containers after use or has been contaminated with rust, grease or other debris, shall not be re-used without cleaning in accordance with the wire manufacturers advice. All wire that cannot be cleaned without damage to the surface, change in size or other damage that would adversely affect its use shall be discarded. Consumables that cannot be identified to the satisfaction of the Principal shall be removed from the work site and any welds made with such consumables shall be cut out and re-welded.




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3. GENERAL REQUIREMENTS 3.1. WELDING PROCEDURES Welding Procedure Specifications (WPS) shall be qualified for all welded joints in accordance with the relevant part of ISO 15614, and as amended by this Standard. Each individual Contractor shall prepare and qualify their own WPSs. These shall contain information as listed in either ISO 15609 or ASME IX, and this Standard. Production welding shall not proceed until WPSs have been approved by the Principal. Combination of WPQRs with other companys procedures, even if a combined operational control exists, is not permitted unless specific approval is given by the Principal. Prior to submittal to the Principal the Contractor shall ensure that all WPS and WPQR documentation is accurate and fully in compliance with contract design requirements. The testing results for WPQR shall be laid down in a precise and detailed format. Unless otherwise identified, multi-pass fillet welds may be qualified by groove welds in accordance with ISO 15614, although separate WPS's shall be submitted. Single pass fillet welds shall be separately qualified in accordance with ISO 15614. The approval of WPS by the Principal is subject to acceptable performance in subsequent production. Approval may be withdrawn where excessive repair rates are encountered that cannot be attributed to bad workmanship. 3.1.1. Qualified Procedures WPSs previously qualified by the Contractor may be submitted for approval provided they meet the requirements of this Standard and they are supported by WPQR witnessed by an acceptable Independent Third Party. The Contractor shall be able to furnish evidence of the successful application of the proposed procedures from previous work. 3.1.2. Procedures to be Qualified The Contractor shall prepare, for Principal approval, a preliminary WPS for each welding procedure proposed, or a welder instruction card containing Specification parameters for the nominated process and consumable combination. If acceptable it shall be approved for qualification only. Procedure qualification shall then be performed according to these instructions. Procedure documentation, including the final WPS, (which may be modified from the original submission according to the parameters actually used during qualification), and welder instruction card (if adopted), shall be submitted to the Principal or his designated representative for final approval. As a minimum the WPQR documentation shall include the information specified in Appendix A of this Standard. 3.1.3. Essential Variables Any change to the welding procedure outside the allowances of the essential variables in ISO 15614, or the variables shown in this Standard shall require re-qualification. Where the thickness range of a weld procedure extends past a threshold where additional or more severe testing would be required, the qualification range shall be limited to that threshold unless the additional testing is performed. Unless otherwise specified the qualified diameter range for process piping shall be 0.5xOD to 2xOD.




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In preparing qualification records and weld procedure specifications, care should be taken to distinguish between factored heat inputs and unfactored arc energy. Arc energy is the preferred method for welding documentation, but heat input can be used if this is the normal methodology applied on site. Factored arc energy, i.e. heat input, should be used when applying process limits and calculating preheat levels. 3.1.4. Welding Procedure Qualification Testing WPQR testing shall not commence without the presence of a representative of the Principal unless permission has been given to the contrary. The Contractor shall record all the information required for WPQR as defined in Appendix A of this Standard. The Contractor should supply all instrumentation necessary to record the applicable welding essential variables as required by this Standard, Appendix A, i.e. portable arc monitoring systems, current meters, temperature measurement devices, etc. All such equipment shall have a current and valid certificate of calibration. The WPQR, inclusive of all recorded data, shall be signed as witnessed by the Contractor and submitted to the Principal. Mechanical testing shall be performed as per ISO 15614 and the additional requirements in this Standard. Designated testing laboratories shall have a quality system in compliance with ISO 17025 or equivalent. When specified PWHT shall be carried out in accordance with section 3.3.9. of this Standard. 3.1.4.1. WPQR Non-Destructive Testing The following NDE shall be performed.

Butt Welds Visual (section 3.4.2.)

MT ferrous materials or PT for non-ferrous materials (sections 3.4.3. or 3.4.4.)

Radiography (section 3.4.5.) Ultrasonic (3.4.6.), if specified for the material.

Fillet Welds Visual (section 3.4.2.)

MT ferrous materials or PT for non-ferrous materials (sections 3.4.3.or 3.4.4.)

Visual examination of the completed weld shall be conducted by both the Contractor and the Principal. Cutting of the test piece for mechanical testing should not take place until it has been visually examined and accepted by a representative of the Principal. Should the completed test piece diameter be too small to allow proper examination of the weld root, the test piece shall be cut longitudinally to facilitate examination. Radiographic examination for WPQR shall be by X-radiography. If alternative or additional NDE methods are proposed for production welding, the test weld shall also be subjected to these methods.




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3.1.4.2. Macro Examination Macro sections shall be prepared so that the whole cross section of the weld, inclusive of HAZ, and adjacent parent material may be examined. These should be etched to reveal individual passes and the full extent of the HAZ. Macro sections shall be examined at a magnification of x5. WPQR documentation shall include macro-photograph(s) of the sections. Any hardness survey indentations shall remain visible on these macro-photographs. Macro-photographs shall be marked to indicate the magnification. Only original photographs or good-quality digital images shall be accepted as part of the welding procedure qualification documentation. For acceptance the macro examination shall be free from cracks, lack of fusion (root, sidewall or inter-run) or volumetric defects (slag, porosity, etc) outside the limits set by Tables 6 & 7 of this Standard. At the request of the Principal volumetric defects may be further investigated by grinding and/or re-sectioning to define their extent. Fillet welds shall meet the following, additional requirements:

Fillet welds shall show full fusion to the root of the fillet. The length of each leg shall be equal to or greater than the specified weld size and there shall be no more than 3mm difference between the two. The throat thickness shall be at least 0.7 x the specified leg length. Convexity or concavity shall be no greater than 1.5mm.

3.1.4.3. Hardness Testing Hardness surveys, as described in ISO 15614, shall be carried out using Vickers hardness at 10Kg load on a macro section prepared as above. Testing shall be in accordance with ISO 6507-1. 3.1.4.4. Charpy Impact Testing As a minimum Charpy impact testing is required to demonstrate compliance with the European Pressure Equipment Directive (97/23/EC). Therefore for WPQRs to support fabrication of usually non-Charpy tested materials, i.e. ASTM A105 or A106 grade B, these shall be subject to Charpy testing at a minimum temperature of 0C, or the minimum design temperature, whichever is lower, and display a minimum average Charpy impact resistance of 27J. For all other materials Charpy Impact testing shall fully comply with the testing requirements of this Standard. Testing temperature and acceptance criteria shall be in accordance with Table 3 of this Standard. Charpy V-notch specimens shall be prepared and tested in accordance with EN ISO 148-1 (2mm radius striker - KV2). For welds made with a maximum heat input of 2kJ/mm, a set of three Charpy impact specimens shall be taken with notches at the weld centre line, fusion line and fusion line + 2mm as shown in Figure 2. Where heat inputs greater than 2kJ/mm have been used during WPQR an additional set of three specimens is to be taken at fusion line + 5mm. For single sided welds, the specimens shall be taken with the lower surface no more than 2mm above the inner surface. Additionally, for material thicknesses of greater than 20mm, a set of three specimens shall be taken with their notches at the weld centre line and with their upper surfaces within 2mm of the outer surface. Each specimen shall be etched prior to notching and the location of the notch relative to the fusion or weld centre line individually marked. The notch shall be placed in the square face of single bevel welds. If the WPQR uses two different materials, fusion line and HAZ specimens shall be taken from both sides. The notch positions for 2-sided welds shall be agreed with the Principal.




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Full size (10mm x 10mm) impact test specimens shall be used wherever possible. Where this is not possible, the larger of three quarter size (7.5mm x 10mm), half size (5mm x 10mm), or quarter size (2.5mm x 10mm) specimens shall be used. Reduced acceptance values for reduced size samples are given in Table 3, note 1. No result shall be less than the specified minimum individual value and not more than one result shall be less than the minimum average value specified. If the above requirements are not met, three further specimens shall be tested. The average of the six specimens shall be not less than the minimum specified average. Only 2 values may be below the specified minimum average value and only one of those may be below the specified minimum individual value. 3.1.4.5. Corrosion Testing Welds in superaustenitic and duplex stainless steels shall be corrosion tested according to ASTM G 48, Method A. Two test specimens are required for 5G or 6G positions. One specimen is sufficient for other welding positions. The test temperature shall be as shown below, and the exposure time shall be 24 hour minimum. The test specimens shall have a dimension of full wall thickness by 25 mm along the weld and 50 mm across the weld. The test shall expose the external and internal surface and a cross section surface including the weld zone in full wall thickness. Cut edges shall be prepared according to ASTM G48 but the internal and outside surfaces shall be left in the as-welded condition. Pickling prior to the test is not permitted unless the test is conducted in accordance with NORSOK M-601 at its higher temperatures (or 25C in the case of 22% duplex).

Material This Specification Test Temperatures (no pickling permitted)

NORSOK M-601 Test Temperatures

22% Duplex 22C 25C 25% Duplex 35C 40C 6%Mo 35C 40C

Note: Previously accepted PQRs on 6%Mo with corrosion testing at 30C do not require retesting at 35C.

The weight loss shall not exceed 4.0 g/m2 and there shall be no pitting visible on the internal or external surfaces at 20X magnification. 3.1.4.6. Metallography / Ferrite Determination Where micro-examination and/or ferrite testing are required, these shall normally be carried out on macro specimens after hardness surveys and photomacrographs have been completed. Ferrite determination of duplex stainless steels shall be in accordance with Appendix C. If the WPQR uses two different components, both HAZs shall be tested. Ferrite check on the weld of 300-series austenitic steels may be carried out using a magnetic ferrite meter, or by point counting in accordance with ASTM E562 using a 100 point grid minimum. 3.1.5. Repair Welding Procedures Separate WPSs shall be prepared for repair welding. Repair welding shall normally be carried out to the same procedure as the original welding. Therefore unless otherwise noted in this Standard (see section 3.5. and section 4.) for non-sour service, repair WPQR shall not be required.

The Contractor shall submit to the Principal for approval a general repair procedure detailing: The method of defect excavation; The shape and size of excavation prior to re-welding; All inspections prior to re-welding;




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The WPS and WPQR, if different from original weld.

Where a different welding procedure (ie. a change of process or other essential variable) is to be used for repair welding, or sour-service hardness criteria apply to the material, the repair WPS shall be qualified in accordance with this Standard. Qualification shall require the reproduction of a typical production repair. Full penetration and partial penetration excavations shall be qualified separately. For part wall excavations the remaining ligament adopted for the test weld shall be the smallest allowed in production. Repair welds shall generally be tested in accordance with the requirement for the original weld. Where impact testing had been specified for the original weld, impact testing of the repair weld metal and the adjacent HAZs, both in the parent material and the original weld metal, shall be carried out at the test temperature of the original weld. Where repair welding is performed using the same procedure as the original weld, tensile and bend tests are not required for the repair WPQR. 3.2. WELDER QUALIFICATION 3.2.1. General All welders and welding operators shall be qualified in accordance with this Standard and ASME Section IX, EN 287-1, ISO 9606 or EN 1418 as applicable or equivalent codes. Fillet welds may be qualified by groove weld performance tests, where the national codes permit this. (NB. The 2012 draft of ISO 9606-1 does not permit fillet welds to be qualified by butt welds.) For site erection and offshore hook-up qualification testing shall be in the 6G position. Whilst on site the welders and welding operators shall be easily identifiable. This may be by:

A badge bearing name, photograph and identification number, The welder carrying a works ID pass including a photograph By the Contractor maintaining a report of welder IDs including name, photograph, and welder ID number.

In the event that a welder leaves the work his welder number shall not be assigned to another welder employed on the work. 3.2.2. Pre-Qualification Welders qualified on work other than for the Principal shall be accepted provided:

Their qualification has been carried out in accordance with ASME Section IX, EN 287-1, ISO 9606 or EN 1418 as applicable, and the requirements of this Standard.

Their qualification testing has been witnessed by a Certifying Authority or independent third party acceptable to the Principal, and the certificate of qualification is endorsed as acceptable by the Authority;

The Contractor can give proof that the welder has been continuously employed by him for the previous six months and has been welding with reasonable continuity during that time, to the same, or similar, procedures with satisfactory results.

3.2.3. Documentation Prior to commencement of work, the Contractor shall submit:

A register of the welders to be used on the work, giving the procedures, positions and thickness ranges in which they are qualified, together with the identity number for each welder; All welding performance qualification certificates, including relevant back-up documentation, such as NDE and mechanical test certificates.




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3.2.4. Time Limitations Welder and Operator performance qualification is valid for a six-month period from the date of approval. Qualification certificates may be re-approved for further periods of six months provided the welder has been employed with reasonable continuity on welding covered by the performance certificate. The essential variables in EN 287 applicable to performance qualification apply to the time limitation and continuity criteria. If there are reasonable grounds to question that welders ability to weld to the specified procedure the Principal may demand the re-qualification of any welder, at any time. 3.2.5. Tube-to-tubesheet welding When a welded tube-to-tubesheet joint is specified on the equipment data sheet, it shall be a full strength-welded joint. Autogeneous seal welds are not permitted. Unless otherwise stated the qualification of the strength-welded tube-to-tubesheet joints shall be in accordance with the requirements of ASME Section IX, paragraph QW-193 or the applicable pressure design code. The following additional requirements shall apply if a strength-welded tube-to-tubesheet joint is specified: The degree of expansion shall be agreed between the Supplier and the Contractor, with consideration of the tube and tubesheet materials, hardness, and potential for work hardening during the expansion process. All mechanical testing shall take place after expansion. A minimum of two (2) weld passes shall be applied using the GTAW technique. The length of the combined weld legs measured parallel to the longitudinal axis of the tube at its outside diameter shall be at least 1.4 times the nominal thickness of the tube. A tensile pull-test shall be performed on the qualification test coupon. A minimum of three tests shall be performed. Where the material is too thin to allow HV5 hardness surveys to be performed, Contractor shall propose an alternative (eg. low load Vickers or Micro-Hardness survey) for approval by the Principal. Results shall satisfy the HV5 acceptance criteria. 3.3. WELDING - GENERAL REQUIREMENTS 3.3.1. Shop/Site Conditions The Contractor shall submit to the Principal a list of all welded joint types to be encountered in terms of size, material and position, and the welding procedures by which they shall be made. The welding environment should be such that all welding is adequately screened from draughts and inclement weather. Particular care shall be taken where gas shielded methods are employed. If in the opinion of the Principal adequate protection is not provided, work shall be halted until the situation has been rectified to the satisfaction of the Principal. When fabrication is to be carried out in the vicinity of plant or equipment which may be damaged or otherwise compromised by such planned construction work, i.e. weld spatter, cutting droplets, fumes, grinding dust, etc., then adequate protection shall be provided for this ancillary plant and equipment. Prior to welding the Contractor shall submit, for approval by the Principal, a procedure for the segregation of all materials in the work scope and control of the tools to be used with them.




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The shop fabrication of stainless steel and other non-ferrous process piping and equipment work shall be carried out in a separate area from that of Carbon-Manganese and low alloy steels. Titanium welding shall be carried out in a fully enclosed quarantined area dedicated to Titanium fabrication. Care shall be taken to avoid overstressing or other mechanical damage to any process equipment or piping fabrication at all stages of the work. 3.3.2. Equipment All equipment shall be in good condition and properly maintained with records to support its ongoing safe operation. 3.3.2.1. Gas Cutting Equipment All gas cutting equipment shall comply with ISO 5172. 3.3.2.2. Welding Equipment All welding equipment shall be in accordance with the relevant sections of EN60974-1. Ammeters and voltmeters shall be fitted to welding equipment for the GMAW, FCAW and SAW welding processes. Separate voltmeters and ammeters (tong tester or Hall effect type) shall be provided for all other welding processes. All welding equipment and associated meters shall be verified as calibrated immediately prior to the commencement of production welding and thereafter at regular intervals according to the Contractors calibration procedure. This procedure shall be agreed with the Principal before the start of production. 3.3.2.3. Grinding and Cleaning Equipment Wire brushes and grinding discs shall be dedicated to one material type. Only stainless steel wire brushes shall be used for non-ferrous materials. Precautions shall be established to ensure that grinding wheels, files, wire brushes and similar tools that have been used on Carbon-Manganese and low alloy steels are not used for fabrication of any other material. 3.3.3. Preparation for Welding 3.3.3.1. Permitted Weld Detail All vessel, process piping and other equipment main pressure retaining joint welds shall be fabricated with full penetration butt welds unless otherwise specified. Permanent backing strips shall not be used. Fusible inserts or removable backing strips may only be used with the approval of the Principal. Where fillet welds are used in piping design, the requirements of ASME B31.3 shall be applied. Socket welded fittings shall not be permitted unless approved by the Principal. 3.3.3.2. Weld Preparation All material shall be visually inspected prior to welding to confirm freedom from mechanical damage/ corrosion and confirm correct marking. Any anomalies shall be reported in writing to the Principal Deep gouges and dents on the preparation surface shall be cause for rejection. Weld repair of such defects shall only be permitted by approval of the Principal. Laminations identified on the bevel surface by visual examination shall be investigated by MT or PT) prior to removal. Weld preparations shall be in general accordance with ASME B16.25. Square butt ends are permissible below 2mm wall thickness. Weld preparations and a distance 50mm either side shall be free from rust, scale and other contaminants. Prior to preparation/fabrication/cutting of vessel wall or process piping for branch connection i.e. flange or weldolet attachment, UT examination shall be performed to confirm freedom from injurious defects.




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Where applicable, wooden or plastic covers shall be provided to protect weld bevels from mechanical damage and prevent ingress of foreign material into the vessel, piping or other process equipment. 3.3.3.3. Cutting and Bevelling Ferritic steel items may be cut mechanically or by oxy-fuel gas cutting. Weld bevels shall be prepared by machining or by mechanically guided flame cutting. Bevelling with hand-held cutting torches is not permitted except when specifically approved by the Principal. Flame cut bevel surfaces shall be ground to bright metal unless the welding procedure was qualified with surfaces in the same condition. 3.3.3.4. Alignment Equipment used to hold and support process equipment, vessels, piping, etc., shall be capable of bearing the load in a safe manner whilst maintaining the stability required for working in both the vertical and horizontal planes. The permitted maximum misalignment for piping butt welds shall be:

Internal

Pipe Diameter Misalignment 100mm 1.6mm (3.0mm when welding is carried out from both sides)

External

Pipe Diameter Misalignment 12mm Pipe thickness/4 > 12mm 3.0mm

For vessels and other equipment misalignment shall be in accordance with the design standards. Misalignments greater than these limits may be corrected by grinding or machining to a taper of 1:4 provided the wall thickness is not reduced below the minimum tolerance. Reforming of process piping vessel walls or other equipment, either hot or cold shall not be attempted without the approval of the Principal. For general tolerances, refer to DEP 31.38.01.31-Gen 3.3.3.5. Spacing Pipe or vessel longitudinal seams shall be separated by at least 45 degrees of rotation or 150mm, whichever is the less. Circumferential welds shall be separated (toe to toe) by at least 4 times the nominal wall thickness or 50mm, whichever is greater. Attachments shall be separated by at least 2 times the nominal thickness or 50mm (toe to toe) from any weld, whichever is the smaller. 3.3.3.6. Tack Welding and Clamping Tack welding shall be carried out following the root parameters of the qualified WPS and shall be performed by qualified welders. Tack welds shall be at least 25mm in length and shall be equally spaced around the circumference in sufficient number to support the process piping, equipment or fitting. The preferred method of tack welding for single sided welds shall be by the temporary welding of a short length of round bar along the bevel faces of the preparation. The bar material shall be specified by the Contractor and approved by the Principal. Tack welds intended to be an integral part of the root weld shall be ground to a taper edge to facilitate weld pick-up.




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Cracked or badly profiled tack welds shall be completely removed prior to welding. If line-up clamps are used without tack welding they shall not be removed until after the root and hot pass have been fully completed. 3.3.4. Weld Execution 3.3.4.1. Identification Welds shall be uniquely identified. The Contractor shall demonstrate to the satisfaction of the Principal that individual welds can be positively identified at all stages of construction. Particular attention shall be given to maintaining identification during grit-blasting and painting. Weld identification numbers shall be marked adjacent to the weld by crayon, paint stick or similar marker prior to welding. Similarly, welders shall mark their numbers adjacent to each weld they make. 3.3.4.2. Cleaning Weld preparations and a distance 50mm either side shall be cleaned to remove rust, scale, oil, grease and other contaminants. Filler wires shall be cleaned with stainless steel wool and solvent. Cleaned filler wires shall only be handled by welders using clean gloves that have been used for handling only one material type. On completion of fabrication the Contractor shall clean the inside and outside of all fabricated assemblies of all loose material, scale, slag and weld spatter. 3.3.4.3. Back purging Back purging is required to maintain internal weld surfaces, and parent metal adjacent to weldments, clean and free from scale and excessive oxidation (slight bluing is permitted for nickel alloys and stainless steels ). The method of application for back purging welds shall be detailed either in the relevant WPS or in a separate document referred to by the WPS. This shall be approved as part of welding procedure qualification documentation endorsement. The use of soluble dams for minimising back purge requirement during piping fabrication should be approved by the Principal. Their application shall be in accordance with the Manufacturers recommendations. When dams are to be used on site, working procedures shall ensure their removal after welding. For fabrication of carbon and low alloy steels, when using solely gas shielded welding processes, unless demonstrated to the contrary during welding procedure qualification trials, back purging with high purity Argon is required. This back purge shall be maintained for a minimum of the root pass. The use of another gas or gas mixture may be proposed for consideration by the Principal. For GTAW of 3% Nickel steels, back purging is mandatory. Welds made in austenitic, Nickel alloys and Copper-Nickel shall have a back purge which shall be maintained for a minimum of the root and second pass. Welding 6 Mo stainless steel requires that the purge be maintained for the first three layers. 22% Duplex stainless steel welds shall use a back purge of high purity Argon containing 2-3% Nitrogen. However, if the root is carried out with a 25% duplex consumable then high purity Argon may be used. The purge shall be maintained for a minimum of the first three layers.




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25% Duplex stainless steel welds shall use a back-purge of high purity Argon with, or without nitrogen addition. The purge shall be maintained for a minimum of the first three layers. Titanium welds shall use a back purge of high purity Argon, Helium or Argon/Helium mix, as qualified during welding procedure qualification trials. The purge shall be maintained continuously until the metal temperature drops below 500C after the completion of welding. For all corrosion-resistant materials requiring back-purging, the purge shall be applied for a period long enough for the oxygen content of the exit gas to fall at least below 0.5% and preferably 0.1%. This shall be demonstrated during weld procedure qualification and production by means of a suitable oxygen meter. The acceptance criteria for oxidation of stainless steel weldments shall be in accordance with NORSOK M-601 Annex B or DEP 30.10.60.31-Gen. As-deposited weld beads and HAZs of titanium welds should be inspected after each pass for the degree of oxidation. Light and dark straw coloured oxides are permissible, but dark blue, light blue, grey, and white deposits indicate progressively unacceptable contamination that leads to embrittlement. Removing these oxide deposits will not improve the underlying damage to the material properties, so welds exhibiting these undesirable oxide colours shall be rejected. The cause of the contamination shall be rectified before production continues. 3.3.5. Preheat Temperature Requirements For Carbon-Manganese and low alloy steels, the minimum preheat shall be as calculated in accordance with EN 1011-2 using the maximum Carbon equivalent allowed for the material to be welded and the weld metal hydrogen level guaranteed by an approved consumable control procedure. For WPS preheat determination the heat input used in the calculation should be the lowest single pass value recorded during WPQR. If higher preheats are found to be necessary to meet the hardness values required by this Standard, particularly for sour service conditions, the temperature margin above the minimum required by EN 1011-2 shall be preserved for all thicknesses to be welded. For 3% Nickel steels, a minimum preheat of 100C shall be used for welding all thicknesses. Where reinforced branch fittings such as olets that are to be welded, the minimum preheat shall be 50C above that indicated by EN 1011-2. When preheat is not explicitly required by this Standard and ambient temperature is below zero, or condensation/moisture is apparent on work surfaces, then sufficient preheat should be applied to ensure work surfaces are dry and remain warm to touch. 3.3.5.1. Preheat Application For up to and including 19 mm wall thickness, preheating shall be by gas torch or electrical resistance heaters. Above 19 mm, electric resistance heating mats should be used unless it is agreed with Principal that access or location makes it impractical. Electric resistance elements shall be controlled by thermocouples attached on or adjacent to the weld preparation. Thermocouple devices shall be regularly calibrated according to a procedure agreed with the Principal. Preheating with oxy/fuel gas should only be by soft flame burners designed for the purpose. Hand held oxy/fuel gas burners may only be used for welds less than 150mm OD or attachment welds less than 300mm long. Non-electrical preheat temperature should be measured using contact pyrometers, temperature indicating crayons or thermocouples. Where access permits measurement shall be from the opposite




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surface of the work being heated and shall be at a location displaced from the source of heat by a minimum of 25mm in a direction parallel to the vessel, process piping or other equipment axis. Measurement shall be after removal of the heat source. If access is not possible to the opposite surface temperature measurement shall be taken 75mm from both weld toes / edges and delayed for a period not less than 2 seconds per mm of thickness after removal of the heat source. Temperature indicating crayons shall be certified free of lead and sulphur. Residue from crayons shall be removed from the weld surface before proceeding with the weld. 3.3.5.2. Interpass Temperature In general the maximum interpass temperature shall not exceed that measured during PQR by more than 50C, though there may be additional limitations in the relevant material-specific section. 3.3.6. Interruption of Welding For CMn, LTCS, low-alloy, and 3.5% nickel steels, the root and second pass shall be completed as a minimum before it is permissible to interrupt welding progress and allow the joint to cool below the minimum preheat temperature. If cooling has occurred and the completed weld ligament depth is less than 25% of the total joint thickness then surface inspection (MPI or DPI) shall be performed to ensure freedom from deleterious defects. When interruption of welding ferritic steels is unavoidable then slow cooling is mandatory and shall be achieved by wrapping the joint in a suitable insulation material. 3.3.7. Arc Strikes The welding arc shall only be struck on the prepared welding surface or previously deposited weld metal. Any erroneous arc strikes shall be removed by grinding or other suitable method and the area shall be subject to surface inspection (MT or PT) to ensure continued freedom from defects. The thickness of material remaining after the removal of such defects shall be measured. If this measurement reveals loss of wall thickness below the minimum required thickness then the item shall be replaced. Weld repair of such areas shall not be permitted. 3.3.8. Weld Finish All welds shall be finished with a smooth profile, without overlap, abrupt ridges or valleys, and shall blend smoothly with the base material. Toe profile grinding or cosmetic grinding shall only to be carried out when directed by the design drawings or with the approved of the Principal. If fillet welds are concave, or not equal, the minimum throat size shall not be less than 0.7 x the specified leg length. For olet branch fittings the root profile shall be as specified for full penetration butt welds. The contour of completed welds shall be as shown in Figure 3 of this Standard, unless the Principal advises that the design requirement can be met with a smaller weld. 3.3.9. Post-Weld Heat Treatment For Vessels, pumps, instruments and any other ancillary process or utility equipment PWHT shall be in accordance with the ruling design codes and as detailed in the relevant standards included in the purchase order. 3.3.9.1. Piping PWHT requirements Fabrication of NON IMPACT tested CMn steel piping and fittings (i.e. ASTM A105, A106 grade B, etc.), shall be subject PWHT if the wall thickness exceeds 19mm unless advised otherwise on the design drawings or by the Principal.




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For branch connections in NON IMPACT tested steels the wall thickness, t, shall be taken as the governing thickness as defined in ASME B31.3 Section 331.1.3. Fabrication of IMPACT tested CMn piping and fittings, for process piping service (i.e. ASTM A333 gr6, A350 LF2, etc.), shall be subject to PWHT if the wall thickness exceeds the thickness B as defined in Table 1. NB. For branch connections in impact tested steel, PWHT is required where the wall thickness of the fitting exceeds thickness B, as defined in Table 1, or where, for olet branch fittings, the maximum thickness of the fitting exceeds 4B, or the weld thickness exceeds 38 mm (refer to Figure 3). All welds in AISI 4130 material shall be subject to PWHT. If there is no subsequent machining operation all threads and gasket surfaces shall be protected from oxidation whilst equipment is subject to heat treatment. Non-ferrous materials do not normally require PWHT. However, if approval is granted or if directed by the Principal, e.g. where austenitic steel shall be welded to CMn steel, PWHT shall be carried out generally in accordance with this section. Additional restrictions as deemed necessary for the materials involved will be advised by the Principal. 3.3.9.2. Procedures All PWHT shall be carried out in accordance with a procedure approved by the Principal prior to commencement of heat treatment. As a minimum the procedure shall include the following information: name of (sub) Contractor; ruling Specification; material and item type; method of heating; fuel gas and method of atmosphere control (if gas-fired furnace); size and type of electrical element (if electrical resistance); type, location and number of thermocouples; method of thermocouple attachment; details of loading and supporting arrangements to avoid distortion; provisions to avoid flame impingement (if flame heated) holding time and temperature; heating and cooling rates; type of recording equipment including number of channels; chart speed. 3.3.9.3. Conditions Holding temperature CMn steels 580C - 620C 3% Nickel steel 590C - 630C CrMo steel (AISI 4130) 660C - 700C

Alternative holding temperature may be submitted for Principal consideration providing this application is supported by appropriate data. In the case of quench and tempered steels the actual holding temperature shall be at least 25C below the finishing temperature recorded on the material certificate. Holding time t 25mm t/25 hours Maximum heating rate above 300C

t 25mm 220 x 25/t C/hour




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Maximum cooling rate above 300C

t 25mm 275 x 25/t C/hour (Cooling in still air is permitted below 300C.) 3.3.9.4. Furnace PWHT Wherever possible PWHT shall be performed in a fully enclosed furnace. Fuel powered furnaces shall have adequate flame controls to avoid an oxidising furnace atmosphere. Flame impingement onto PWHT items is not permitted. During heating and cooling the temperature shall not vary by more than 150C in any 4500mm length. The number of thermocouples shall be sufficient to ensure that the temperature and thermal gradients of the whole of the work are within the required range. One thermocouple shall be attached directly to each spool or assembly at the point of greatest wall thickness. If a large number of small spools/assemblies are to be treated in one batch, thermocouples may be attached to a representative number (no less than one in four) of the spools. 3.3.9.5. Local PWHT Local PWHT shall be allowed where size or installation restrictions prevent furnace treatment. In this case heating shall normally be by electrical resistance heating elements. Other heating methods may be considered. These should be submitted for review and approval by the Principal. For local PWHT the soak temperature shall be achieved and maintained in a band 2.5 x weld thickness (e) either side of the weld centre line. The width of the thermal insulation shall be 7.5e either side of the weld centre line. Circulation of air in the bore of the process piping or equipment work shall be prevented. The minimum number and position of thermocouples shall be as follows:

External Dia. mm No. of Thermocouples per Weld

Clock Position

100 1 12 >100 to 300 2 6, 12 >300 4 3, 6, 9, 12

Thermocouples shall be located on the weld centre line and shall either be held in direct contact with the surface of the weld mechanically or be attached by capacitance discharge welding. The attachment points of capacitance discharge welded thermocouples shall be dressed by grinding after removal. 3.3.9.6. Calibration The Contractor shall approve calibration procedures for all equipment measuring and recording temperature. As a minimum temperature recorders shall be calibrated every three months. 3.3.9.7. Recording and Reporting As a minimum heating rate, holding time, temperature and cooling rate data shall be recorded. The temperature measured by each thermocouple should be recorded by means of a multi-channel chart recorder. Each chart shall be marked with the date of the PWHT, the weld or spool/assembly number(s), channel identification and signature(s) of sub-Contractor personnel. A heat treatment report shall contain sufficient information to ensure traceability to the item(s) under treatment and confirm compliance with the approved procedure.




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It shall also contain an authorised signature confirming completion of works in accordance with design requirements. Completed charts shall be available for Principal review, together with the heat treatment report(s). 3.4. WELD INSPECTION 3.4.1. General Requirements Weld inspection, as detailed below, shall be the responsibility of the Contractor. Unless otherwise approved by the Principal, the NDE Company responsible for the final inspection of welds shall have a quality system in compliance with ISO/IEC 17020, or equivalent, and be accredited by a nationally recognised body. The Contractor shall submit NDE procedures to the Principal for review and approval prior to the work commencing. These procedures shall clearly illustrate how visual, surface and volumetric inspection techniques will establish that all welded joints meet the quality requirements of this Standard. The Contractor shall implement a system for uniquely identifying each weld, for the control and recording of inspections (VT, MT, PT, UT and RT). It is recommended that isometric drawings, marked with the individual weld numbers, be maintained for this purpose. Prior to fabrication start-up, the Contractor shall submit his process for approval by the Principal. The causes for each defect shall be immediately investigated and corrective action shall be taken to prevent further occurrence. The defects shall be reported with reference to the numbering system according with ISO 6520-1. The Contractor shall implement a system for recording of weld defect rates. The defect rates shall be recorded on a weekly basis for each production area and shall be reported together with the accumulated defect rate. Individual welders shall be identified in the defect rate recording system. When required by this Standard the Contractor shall submit to the Principal a procedure for production welding parameter monitoring. This procedure shall include details of the method(s) used, reporting process and the frequency of tests related to the number of welders, processes, and shift patterns. Where PWHT is required, final non-destructive acceptance testing shall not take place until final PWHT has been completed. 3.4.2. Visual Inspection Personnel performing visual testing of welded joints shall be qualified in accordance with EN 473, VT level 2, or equivalent. Visual inspection shall be carried out on all prepared joints prior to welding, during welding (welder self checks) and upon completed welds. Pre-weld checks shall include compliance with clause 4.3 and the tolerances of the WPS. Verification checks shall include the internal surface of the weld wherever possible. The visual acceptance of each weld shall be recorded by the Contractor. 3.4.3. Magnetic Particle Inspection Magnetic particle inspection shall be used as the surface inspection technique applied to non-impact/impact tested CMn steels, low alloy steels, 3.5 nickel steels, ferritic/martensitic stainless steels and any other ferritic alloy. This inspection shall be carried out in accordance with ASME V, Article 7.




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Examination areas shall be cleaned prior to inspection and shall be free from surface irregularities, such as weld spatter. Magnetisation shall normally be by electromagnetic yoke using alternating current. Coil or parallel conductor methods shall only be used if approved by the Principal. Only the wet method shall be employed, using either black ink on white background or ultra-violet fluorescent ink. The total coating thickness allowable, including contrast paint, shall be 20m. 3.4.4. Liquid Penetrant Testing Liquid penetrant testing shall be used as the surface inspection technique applied to 6% Mo stainless steels, duplex stainless steels, nickel alloys, copper alloys, titanium and any other non-ferritic alloys. This inspection shall be carried out in accordance with ASME V, Article 6. Examination areas shall be cleaned prior to inspection and shall be free from surface irregularities, such as weld spatter. Colour contrast, solvent removable penetrant shall normally be used. 3.4.5. Radiographic Examination Radiography shall be in accordance with EN 1435, class B improved techniques. The permitted penetrated thickness ranges for gamma ray sources and X-ray equipment above 1 Me V shall comply with EN 1435 table 1. Alternative techniques may be used providing it can be demonstrated that the required sensitivity can be achieved for each procedure proposed. For general radiography, only lead intensifying screens shall be used. Fluorometallic screens may be used in particular cases, if approved by the Principal, where the purpose is to extend the practicable range of radiography. The radiographs shall be positively located relative to a marked datum point on the weld. For radiographs other than those taken with the DWDI technique this shall be affected by means of a number tape with lead numbers at a maximum of 100mm spacing. For DWDI radiographs shall be identified as A, B C, etc., by means of lead letters. The centre line of these three exposures shall be marked on the weld. 3.4.6. Ultrasonic Examination Ultrasonic examination of welds shall be carried out where the material properties allow in accordance with ASME V, Article 5. On branches, O-lets and similar geometrys, scanning from the internal surface shall be carried out if practicable. 3.4.7. Inspection Personnel The inspection personnel to be used by the Contractor shall be individually approved by the Principal. The Principal reserves the option to interview operatives and, when necessary, to require a practical skill test. The minimum personnel qualification requirements are EN 473 Level 2 Additionally, supervisors responsible for overseeing and controlling NDE activities shall be Level 3 qualified.




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Alternative qualifications (e.g. SNT) will be accepted only by specific approval of the Principal. Approval will be subject to satisfactory demonstration of independence and control of the qualification Specifications. 3.4.8. Extent of Inspection of Process Piping Production Welding Table 4 provides guidance for process and utility piping inspection class definition, in terms of piping service and pressure rating. More specific inspection requirements may be included in the purchase order in the form of specific equipment design standard(s) and/or construction drawings. The required extent of inspection for piping fabrication for each class is listed in Table 5. For non-impact/impact tested CMn steels, low alloy steels, 3.5 nickel steels, ferritic/martensitic stainless steels and any other ferritic alloy ultrasonic examination shall be carried out for wall thickness in excess of 19mm, unless otherwise specified by the Principal. For 6% Mo stainless steels, duplex stainless steels, nickel alloys, copper alloys, titanium and any other non-ferritic alloys of wall thicknesses over 19mm radiography is the preferred inspection technique for volumetric examination. Percentage radiography refers to the number of whole welds to be 100% inspected by the radiographic technique. Welds shall be selected so that the maximum number of welders will be evaluated. Should an Inspection Class 1 or 2 weld contain unacceptable defects, two further welds made by that welder shall be inspected by radiography. If either of these proves unacceptable, all welds produced by that welder shall be considered unacceptable unless proved otherwise to the satisfaction of the Principal. All welds found to be unacceptable shall be removed or repaired. 3.4.9. Acceptance Specifications Visual Examination prior to welding Verify compliance with dimensional control requirements

of this Standard. Parameter Monitoring Within the limits of the approved WPS Visual examination of finished welds In accordance with Table 6 of this Standard MT ASME VIII, Appendix 6-4 PT ASME VIII, Appendix 8-4 Radiography In accordance with Table 7 of this Standard Ultrasonic Examination ASME VIII, Appendix 12-3 or as agreed with the Principal

for non-ferritic materials 3.4.10. Reporting All inspection reports should be signed by the approved operative who did the inspection and contain sufficient information to ensure traceability to the weld inspected and the procedure used. It shall record all equipment identification and settings to enable the inspection to be repeated to the same procedure. All defects shall be identified and located relative to a clear reference. Details of the minimum information to be recorded are included in Appendix B. 3.5. REPAIRS 3.5.1. General Repair preparation, remedial grinding and repair welding shall not commence before informing the Principal of the Contractors proposed remedial actions. Second attempts at repairing the same weld area shall only be made by permission of the Principal. Where permission for a second repair is not given the whole weld shall be removed. Welds containing repairs that were made after PWHT shall be heat treated a second time in accordance with this Standard, unless approved otherwise by the Principal.




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3.5.2. Defect Removal Surface profile defects or surface porosity on the cap, or root if accessible, may be removed by disc grinding or burr grinding to a smooth profile subject to the minimum material thickness being maintained. Unacceptable defects in ferritic steels shall be excavated by mechanical means or Carbon arc gouging to a depth agreed with the Principal followed by grinding. Carbon arc gouging operatives shall be approved by the Principal. Unacceptable defects in non-ferrous materials shall be excavated by mechanical means only. The excavation shall be ground to a smooth boat shape with no sharp edges and have sufficient slope on the sides to permit proper access for welding. Weld repair excavation depth shall be controlled by gauges to ensure the minimum amount of material necessary is excavated to completely remove the defect. MT or PT surface inspection techniques shall be used to confirm removal of weld defects. 3.5.3. Root Repairs Where access permits and if approved by the Principal, weld repairs to the root of a single sided weld may be permitted from the inside. This shall be subject to the availability of a suitably qualified repair WPS. Where access does not permit internal rectification, special attention shall be necessary to locate the defect prior to excavation from the outside and to controlling the root gap of the excavation. If the component remains under external loading during defect excavation, the permitted size of the excavation shall be calculated and agreed with the Principal. When necessary assemblies shall be supported whist repair excavations and welding is performed. 3.5.4. Re-welding Repair welding shall be in accordance with section 3.1.5. of this Standard. If, after excavation, the root gap geometry is outside the allowable tolerances of the relevant procedure, a new repair welding procedure shall be qualified unless alternative proposals are accepted by the Principal. If back purging was required for the original weld, the back purge shall be re-established if the repair excavation encroaches closer than 5mm to the inside surface of the vessel, process piping or equipment. 3.5.5. Non-Destructive Testing All repair welds shall be 100% re-inspected by the methods specified for the original weld.




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4. MATERIAL-SPECIFIC ADDITIONAL REQUIREMENTS 4.0.1. General Requirements Requirements vary according to the specific material as shown on the following pages. Common requirements are shown below. It should be noted that the numbering in sections 4.1-4.10 contain deliberate gaps so that the minor sections are similar across all materials (eg. 4.#.4.16 always relates to preheat). Material-specific requirements include lists of approved welding processes. Alternative processes may be permitted by the Principal, subject to a detailed technical justification including documented previous experience. 4.0.2. PQR Requirements PQR Monitoring SMAW : record runout lengths (ROL) and stub lengths PQR Monitoring Other : record minimum and maximum bead widths for each weld area PQR Monitoring Record interpass temperature at start of each pass. 4.0.3. PQR Testing Requirements PQR requirements are generally in accordance with the relevant part of EN ISO 15614, with clarifications changes as indicated for the specific material. Hardness test maxima have been set to allow approved weld procedures to cover all types of process application. These may be relaxed for certain applications where hardness is less critical, by written agreement of the Principal. 4.0.4. Essential Variables Direction of Welding A change from vertical up to vertical down or vice versa requires

requalification. Single/Double Sided Single-sided and double-sided welds require separate qualification. Bevel / V Bevels qualify Vees but not vice versa. Backing Addition or removal of backing strips or gas requires qualification. Shielding / Backing Gases Minor constituents of gases may not be changed by more than 10% Arc Voltage +/- 10% of the average measured for the specified weld region Current / Wire Feed +/- 15% of the average measured for the specified weld region Travel Speed +/- 20% of the average measured for the specified weld region Arc Energy or Heat Input +/- 25% of the average measured for the specified weld region Arc Type A change in arc characteristics (eg. dip, globular, spray) requires

requalification. PWHT Increase in total PWHT time exceeding 25% requires requalification Voltage, current, wire feed, speed, arc-energy, and heat input parameter ranges may need to be modified for certain applications. The above ranges apply unless alternatives are advised by the Principal. Where 2G+5G procedures are required for full coverage, the Principal may accept existing 6G procedures as covering all-positional welding, particularly in the case of manual GTAW and SMAW welding. 4.0.5. Production Controls Requirements for parameter monitoring reflect the sensitivity of the material mechanical and/or corrosion resistance properties. Welding sets shall be validated at intervals not exceeding 12 months in accordance with EN 50504. For some sites, where the problems identified in EN 50504 Annex F apply, documented in-house verification of welding equipment under actual welding conditions may be accepted, Testing equipment used for this




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type of verification shall have a current certificate of calibration which is traceable to national standards, and a detailed procedure, including acceptance criteria, shall be submitted to the Principal for approval.




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4.1. NON-IMPACT TESTED CMN STEELS 4.1.1 General Requirements - Non-Impact Tested CMn Steels4.1.1.1 Typical Materials ASTM A285C, A515, A106B, A105, A234-WPB, API 5L Gr B, A516,

A216 4.1.1.2 Approved Root Processes GTAW (141) 4.1.1.3 Approved Fill & Cap

Processes GTAW (141), SMAW (111), FCAW (136,114), GMAW (135), MCAW (138), SAW (121,125)

4.1.1.4 Consumable Restrictions SMAW electrodes : Shall be type EXX16 or EXX18 4.1.1.6 Consumable Chemistry Root & 2nd pass limited to max 0.3% Ni, 0.6% Si, 0.5% Mo for

hydrocarbon service. For water service, 0.8-1.0% Ni consumables are recommended.

4.1.1.7 Hydrogen Control 5mm See section 3.1.4.4. re. PED requirements 4.1.3.3 Charpy Impacts, T > 20mm See section 3.1.4.4. re. PED requirements 4.1.3.4 Macro + Hardness Survey 1 Required as per EN ISO 15614. Photomacrographs to be included

with indicated magnification not less than 1 and clearly showing all hardness indentations.

4.1.3.5 Maximum Hardness 250HV10 in root up to 8mm from inner surface, 275HV10 above 8mm from inside surface

4.1.4 Essential Variables - Non-Impact Tested CMn Steels4.1.4.1 Carbon Equivalent Production CEq max = PQR CEq +0.03, or 0.38, whichever is higher 4.1.4.5 Thickness Limits (other) As-welded:




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4.2. IMPACT TESTED CMN STEELS (LTCS) 4.2.1 General Requirements - Impact Tested CMn Steels (LTCS)4.2.1.1 Typical Materials ASTM A537, A352, A333 Gr6, A350 LF2, A420 Gr WPL6, API 5L X##,

A694 F## 4.2.1.2 Approved Root Processes GTAW (141) 4.2.1.3 Approved Fill & Cap

Processes GTAW (141), SMAW (111), FCAW (136), SAW (121,125)

4.2.1.4 Consumable Restrictions SMAW electrodes : Shall be type EXX16 or EXX18 4.2.1.6 Consumable Chemistry Root & 2nd pass limited to max 0.3% Ni, 0.6% Si, 0.5% Mo for

hydrocarbon service. For water service, 0.8-1.0% Ni consumables are recommended.

4.2.1.7 Hydrogen Control 5mm Root : Weld, Fusion Line, FL+2mm (and FL+5mm when heat input >

2.0kJ/mm) 4.2.3.3 Charpy Impacts, T > 20mm Root impacts above plus Cap Weld Centreline 4.2.3.4 Macro + Hardness Survey 5G or 6G : 3 off - 3 or 9 oc, 6 o'c, 12 o'c positions. Other welding

positions: 1 off. Photomacrographs to be included with indicated magnification not less than 1 and clearly showing all hardness indentations.


4.2.4 Essential Variables - Impact Tested CMn Steels (LTCS)4.2.4.1 Carbon Equivalent Production CEq max = PQR CEq +0.03, or 0.38, whichever is higher 4.2.4.2 Material Supply Condition Charpy impact and hardness acceptability for Normalised, TMCR, Q&T

materials shall be qualified or demonstrated separately. 4.2.4.4 Thickness For PQRs with T < 5mm, impact tests are not required unless the WPS

is to be used on material with thickness greater than 5mm 4.2.4.5 Thickness Limits (other) See Table 1 4.2.4.6 Position 2G + 5G qualification required for all positional coverage (see 4.0.4). 4.2.4.7 Joint Type Multipass fillets may be qualified by butt weld fill and cap parameters,

unless intended for sour service. 4.2.4.8 Simple / Compound Change to/from compound bevel requires approval by the Principal. 4.2.4.11 Bevel Angle Total included angle shall not be decreased by more than 10 from

PQR 4.2.4.12 Process Combination The welding process, combination of processes or order of welding

processes shall not be changed unless approved by the Principal. 4.2.4.13 Consumable The consumable brand name is an essential variable, though the

Principal may agree to changes for solid wires. 4.2.4.14 Electrode / Filler Rod Size Electrode or filler wire size shall not be changed at any stage of welding

from that used in procedure qualification 4.2.4.15 Polarity / Current Type Any change in polarity or current type requires requalification. 4.2.4.16 Preheat Decrease from that qualified is not permitted. 4.2.4.17 Interpass may be raised by 50C above PQR maximum 4.2.4.18 Interpass Limit 250C maximum 4.2.4.20 Repair Welding Repair WPS to be issued. Separate PQR not required unless essential

variables change, or where sour service is specified. 4.2.5 Production Controls - Impact Tested CMn Steels (LTCS)4.2.5.1 Parameter Monitoring Scheduled, minimum 1 test per process per shift 4.2.5.3 Other Tack welding requires preheating to the minimum level specified on the

WPS or 50C whichever is higher.




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4.3. 3.5% NICKEL STEELS 4.3.1 General Requirements - 3.5% Nickel Steels4.3.1.1 Typical Materials ASTM A333 Gr3, A350 LF3, A420 Gr WPL3, A765 Gr III, A352 LC3,

A203 D 4.3.1.2 Approved Root Processes GTAW (141) 4.3.1.3 Approved Fill & Cap

Processes GTAW (141), SMAW (111), FCAW (136), SAW (121,125)

4.3.1.4 Consumable Restrictions Matching : GTAW : ER80S-Ni2 / SMAW electrodes : Shall be 7016C2L, 7018C2L, 8016C2 or 8018C2

4.3.1.5 Consumable Restrictions Non-Matching : GTAW : ERNiCr-3 / SMAW : ENiCrFe-2 or ENiCrFe-3

4.3.1.6 Consumable Chemistry See restrictions above. 4.3.1.7 Hydrogen Control 5mm Root : Weld, Fusion Line, FL+2mm (and FL+5mm when heat input >

2.0kJ/mm) 4.3.3.3 Charpy Impacts, T > 20mm Root impacts above plus Cap Weld Centreline 4.3.3.4 Macro + Hardness Survey 5G or 6G : 3 off - 3 or 9 oc, 6 o'c, 12 o'c positions. Other welding

positions: 1 off. Photomacrographs to be included with indicated magnification not less than 1 and clearly showing all hardness indentations.


4.3.4 Essential Variables - 3.5% Nickel Steels4.3.4.1 Carbon Equivalent Production CEq max = PQR CEq +0.03, or 0.38, whichever is higher 4.3.4.2 Material Supply Condition Charpy impact and hardness acceptability for Normalised, TMCR, Q&T

materials shall be qualified or demonstrated separately. 4.3.4.4 Thickness For PQRs with T < 5mm, impact tests are not required unless the WPS

is to be used on material with thickness greater than 5mm 4.3.4.5 Thickness Limits (other) As-welded : 12.5mm for service down to -80C 4.3.4.6 Position 2G + 5G qualification required for all positional coverage (see 4.0.4). 4.3.4.7 Joint Type Multipass fillets may be qualified by butt weld fill and cap parameters. 4.3.4.8 Simple / Compound Change to/from compound bevel requires approval by the Principal. 4.3.4.11 Bevel Angle Total included angle shall not be decreased by more than 10 from

PQR 4.3.4.12 Process Combination The welding process, combination of processes or order of welding

processes shall not be changed unless approved by the Principal. 4.3.4.13 Consumable The consumable brand name is an essential variable, though the

Principal may agree to changes for solid wires. 4.3.4.14 Electrode / Filler Rod Size Electrode or filler wire size shall not be changed at any stage of welding

from that used in procedure qualification 4.3.4.15 Polarity / Current Type Any change in polarity or current type requires requalification. 4.3.4.16 Preheat Decrease from that qualified is not permitted. 4.3.4.17 Interpass may be raised by 25C above PQR maximum 4.3.4.18 Interpass Limit 250C maximum 4.3.4.20 Repair Welding Repair WPS to be issued. Separate PQR not required unless essential

variables change, or where sour service is specified. 4.3.5 Production Controls - 3.5% Nickel Steels4.3.5.1 Parameter Monitoring Scheduled, minimum 1 test per process per shift 4.3.5.3 Other Tack welding requires preheating to the minimum level s

T-MCE-STD-001 Rev 0 - Welding and Inspection of Process and Utility Pipework Vessels and Equipment...

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Transcript of T-MCE-STD-001 Rev 0 - Welding and Inspection of Process and Utility Pipework Vessels and Equipment...