GIS 43-331 - API 1104 Pipeline Welding.pdf

Document No.

GIS 43-331

Applicability

Group

Date

21 April 2006

Guidance on Industry Standard for API 1104 Pipeline Welding

GIS 43-331

BP GROUP ENGINEERING TECHNICAL PRACTICES

21 April 2006

GIS 43-331 Guidance on Industry Standard for API 1104 Pipeline Welding

Foreword This is the first issue of Engineering Technical Practice (ETP) BP GIS 43-331. This Guidance on Industry Standard (GIS) is based on parts of heritage documents from the merged BP companies as follows:

British Petroleum GS 118-9 GS 118-10

Welding of Transmission Pipelines (Supplementary to API 1104). Welding of Transmission Pipelines (Supplementary to BS 4515).

AMOCO A PN-OFS-WLD-C

Piping—Offshore—Welding Pipelines—Construction.

Copyright © 2006, BP Group. All rights reserved. The information contained in this document is subject to the terms and conditions of the agreement or contract under which the document was supplied to the recipient’s organization. None of the information contained in this document shall be disclosed outside the recipient’s own organization without the prior written permission of the Director of Engineering, BP Group, unless the terms of such agreement or contract expressly allow.

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Table of Contents Page Foreword ........................................................................................................................................ 2 Introduction ..................................................................................................................................... 6 1

General.................................................................................................................................. 7 1.1 Scope ......................................................................................................................... 7 1.2 Welding process restrictions ....................................................................................... 7 1.3 HSSE for pipeline welding operations ......................................................................... 7 1.4 Pre-production consultation ........................................................................................ 8 1.5 General duties of the contractor .................................................................................. 8 1.6 Quality assurance ....................................................................................................... 8 1.7 Records ...................................................................................................................... 8 1.8 Contractor’s personnel ................................................................................................ 9 1.9 Abbreviations and acronyms..................................................................................... 10

2

Referenced publications ...................................................................................................... 12

3

Definitions of terms .............................................................................................................. 14 3.2 Definitions................................................................................................................. 14

4

Specifications....................................................................................................................... 15 4.1 Equipment................................................................................................................. 15 4.2 Materials ................................................................................................................... 15 4.3 Minimum design temperature (MDT)......................................................................... 17

5

Qualification of welding procedures for welds containing filler-metal additives ..................... 17 5.1 Procedure qualification ............................................................................................. 17 5.2 Record ...................................................................................................................... 18 5.3 Procedure specification............................................................................................. 19 5.4 Essential variables .................................................................................................... 22 5.5 Welding of test joint—butt welds ............................................................................... 25 5.6 Testing of welded joints—butt welds ......................................................................... 26 5.7 Welding of test joints—fillet welds ............................................................................. 33 5.8 Testing of welded joints—fillet welds......................................................................... 33

6

Qualification of welders........................................................................................................ 34 6.1 General..................................................................................................................... 34 6.2 Single qualification .................................................................................................... 35 6.3 Multiple qualification.................................................................................................. 35 6.4 Visual examination.................................................................................................... 35 6.6 Radiography—butt welds only................................................................................... 35

7

Design and preparation of a joint for production welding...................................................... 36 7.1 General..................................................................................................................... 36 7.2 Alignment.................................................................................................................. 36 7.3 Use of line-up clamp for butt welds ........................................................................... 37 7.4 Bevel......................................................................................................................... 38 7.5 Weather conditions ................................................................................................... 38

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7.6 7.7 7.10 7.11 7.12 7.13 7.14


Clearance ................................................................................................................. 38 Cleaning between beads........................................................................................... 39 Identification of welds................................................................................................ 39 Pre-and post-heat treatment ..................................................................................... 39 Weld interruption....................................................................................................... 40 Branches .................................................................................................................. 40 Fillet weld attachments.............................................................................................. 41

8

Inspection and testing of production welds........................................................................... 41 8.1 Rights of inspection................................................................................................... 41 8.2 Methods of inspection ............................................................................................... 42 8.3 Qualification of inspection personnel......................................................................... 42 8.4 Certification of nondestructive testing personnel ....................................................... 42

9

Acceptance standards for non-destructive testing................................................................ 43 9.1 General..................................................................................................................... 43 9.3 Radiographic testing ................................................................................................. 43 9.7 Visual acceptance standards for undercutting........................................................... 44 9.8 Suspect welds........................................................................................................... 44

10

Repair and removal of defects ............................................................................................. 45 10.1 Authorisation for repair.............................................................................................. 45 10.2 Repair procedure ...................................................................................................... 46 10.6 Arc burns .................................................................................................................. 47

11

Procedures for nondestructive testing .................................................................................. 47 11.1 Radiographic test methods ....................................................................................... 47 11.2 Magnetic particle test method ................................................................................... 50 11.4 Ultrasonic test methods............................................................................................. 50

12

Mechanised welding with filler metal additions ..................................................................... 51 12.2 Procedure qualification ............................................................................................. 51 12.3 Record ...................................................................................................................... 51 12.4 Procedure specification............................................................................................. 52 12.5 Essential variables .................................................................................................... 52 12.6 Qualification of welding equipment and operators ..................................................... 52

13

Automatic welding without filler-metal additions ................................................................... 52

Appendix A—Alternative acceptance standards for girth welds..................................................... 52 Appendix B – In-service welding ................................................................................................... 52 B.1 General..................................................................................................................... 52 Appendix C – Additional requirements for pipelines subject to high strain levels ........................... 53 C.1 Introduction ............................................................................................................... 53 C.2 General..................................................................................................................... 53 C.3 Weld procedure qualification testing.......................................................................... 53 C.4 Production welding.................................................................................................... 54 Appendix D—CTOD testing .......................................................................................................... 55 Appendix E—Pin brazing and aluminothermic welding of anode leads ......................................... 55 E.1 Joining technique ...................................................................................................... 55 Page 4 of 56

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E.2


Specification and approval of procedure ................................................................... 55

Bibliography .................................................................................................................................. 56

List of Tables Table A - Grade and thickness limits for cellulosic electrodes ....................................................... 16 Table B - Diameter and test pipe thickness range of approval ...................................................... 19 Table C - Minimum preheat levels for SMAW (cellulosic) welds .................................................... 21 Table D - Specified minimum delay time before NDT for WPQT welds ......................................... 26 Table 2 - Type and number of test specimens (a) for procedure qualification test ......................... 29 Table E - Charpy impact test requirements ................................................................................... 31 Table F - Maximum permissible weld and HAZ hardness values (HV10) ...................................... 33 Table G - Type and number of test specimens for repair weld procedure qualification test ........... 47 Table H - IQI sensitivity levels ....................................................................................................... 49

List of Figures Figure 3 - Location of test pieces from a butt weld in pipe............................................................. 28 Figure A - Charpy V notch locations.............................................................................................. 30 Figure B - Locations for hardness indents ..................................................................................... 32 Figure C - Fillet weld hardness indent locations ............................................................................ 34

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Introduction a.

Guidance for pipeline welding is based on API STD 1104.

b.

Guidance statements of this GIS are modifications to API 1104, Welding of Pipelines and Related Facilities, Twentieth Edition, November 2005.

c.

Modifications to API 1104 are identified as Add, Modify to Read, or Delete.

d.

Paragraph numbers in this specification correspond to API 1104.

e.

Paragraphs of API 1104 that are not revised remain applicable.

f.

If any statement is contradictory to API 1104, the requirements of this GIS shall take precedence.

g.

The technical integrity of all aspects of design, construction, and operation of pipelines is of the highest importance to BP and compliance with BP HSSE policy shall remain paramount.

The normative text of API 1104 and this GIS is primarily applicable to the main line, double joint, and tie-in welding operations for the construction of C-Mn steel and low alloy steel pipelines. This GIS has been written primarily for pipelines up to X80 grade. However, it also allows for construction of pipelines in higher strength steels up to Grade X120 (which are not yet included in the base API 1104 standard and for which some parameters such as mechanical properties and defect acceptance criteria will need to be specified individually).

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1

General

1.1

Scope Add The scope includes the off-line fabrication of items such as welding nipples to valve bodies or other fittings and the fabrication welding of branches. The following items are outside the scope of this GIS: -

Corrosion resistant alloy (CRA) clad linepipe

-

Solid CRA linepipe

-

The welding of process piping in terminals, pump or compressor stations, or in refineries

-

Hyperbaric welding

-

Wet welding

-

Overlay welding

-

Steel catenary risers (SCRs)

Additional requirements for high strain pipelines are given in Appendix C. Requirements for pin brazing and aluminothermic welding of anode leads are given in Appendix E Add 1.2

Welding process restrictions Mechanised and automatic welding processes are preferred and should be used whenever possible for pipeline girth welding. Main line welding should be by mechanised or automatic gas metal arc welding (GMAW) which may include single, multi-torch, or tandem-arc variants of the process and the use of cored wires. If the use of mechanised or automated GMAW processes is impracticable, alternative processes may be used. In such instances, welding may be performed by shielded metal arc welding (SMAW), manual or automated gas tungsten arc welding (GTAW), semi-automatic GMAW processes using solid or cored wires, or a combination of these processes. For double or multiple jointing, girth welds should be made using submerged arc welding (SAW) whenever possible. If SAW cannot be used, the alternative mainline processes listed above may be utilised either alone or in combination with SAW. The welding of pipelines by the oxy-acetylene process or by the flash butt welding process (FBW) or by any other process not defined above is not permitted.

1.3

HSSE for pipeline welding operations Welding, cutting, NDT, and associated operations shall be undertaken in a safe manner and with due regard to individual health and safety and the minimisation of environmental impact. Welding, cutting, NDT, activities and associated operations shall feature in the operational safety planning and in the safety audit schedule. During welding operations, adequate ventilation shall be provided and the quality of breathing air shall be controlled. Further information may be provided by government bodies such as the Occupational Safety and Health Administration (OSHA) in the USA and the Health and Safety Executive (HSE) in the UK. Detail of good practice related to safety during welding, cutting, and associated operations can be found in AWS Z49.1 [1].

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Radiography operations shall conform to local regulations regarding the dangers of ionizing radiation, e.g. in the UK radiography should be undertaken in accordance with the Ionising Radiation Regulations 1999 (SI 1999 No. 3232) and The Approved Code of Practice and Guidance – Working with Ionising Radiation: Ionising Regulations 1999. Environmental guidance shall be taken from EN 14717 when undertaking welding and its associated processes. 1.4

Pre-production consultation Pre-production meetings shall be held with BP, the Contractor and any third-party inspection personnel in order to ensure that all parties fully understand the specified requirements. These meetings shall be held before welding procedure qualification testing and before commencement of fabrication. The BP Welding Engineer shall, as a minimum, be consulted at the following stages:

1.5

a.

During bid evaluation to review the basic welding and NDT methods proposed and to advise on acceptability.

b.

Before weld procedure qualification for approval of the proposed welding procedures.

c.

Before production welding for final WPS approval.

General duties of the contractor Be responsible for quality assurance. Be responsible for the compliance of sub-contractors with this GIS. Unless advised otherwise by BP, supply necessary welding and associated equipment including, but not limited to: heating equipment, fluxes, gases, filler metals, mechanical handling, and testing equipment. If NDT is conducted by the contractor, appropriate NDT equipment including consumables and handling equipment shall be provided. If NDT services and equipment are provided by sub-contractors, ensure that the equipment provided is suitable, well maintained, and, if necessary, is calibrated.

1.6

Quality assurance The quality assurance system shall comply with either ISO TS 29001 (API Q1) or ISO 9001. A Quality Plan for the systematic control of construction, inspection, and testing shall be prepared and implemented. The Quality Plan shall define inspections and tests, the sequence in which they are to be performed during fabrication, and the level of involvement for the contractor’s quality control/inspection personnel, third-party inspection personnel, and BP. The Quality Plan shall be submitted to BP and approval obtained before commencement of fabrication.

1.7

Records Documentation shall be collated, indexed, stored safely, and presented to BP. A log identifying, by number, each pipe or fitting and identifying the weld numbers joining them to other items, shall be compiled. Each circumferential weld (whether a field joint or shopmade weld) shall be allocated a unique number, which shall be used for reference to the weld in reports, radiographs, and test documents.

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1.8

Contractor’s personnel

1.8.1

Welding engineer

A competent and suitably qualified Welding Engineer shall be employed. The Welding Engineer shall be responsible for the technical aspects of welding operations including the following: a.

Selection of welding processes, equipment, and consumables

b.

Preparation and qualification of welding procedures

c.

Qualification of welders

d.

Providing technical oversight of the production welding

e.

Liaison with BP and the NDT sub-contractors

The minimum experience and qualification level for the Welding Engineer should be:

1.8.2

-

In USA: Professional Engineer (PE) holding as a minimum a degree in engineering, metallurgy or materials science and having specialised training in welding technology. Membership of American Welding Society (AWS) is desirable and a minimum of 5 years relevant experience in the pipeline welding or fabrication industry is essential.

-

In Europe/Rest of the World: Chartered Engineer (CEng/ Dipl Ing) holding, as a minimum, a degree in engineering, metallurgy or materials science and having specialised training in welding technology. The requirements of 5.2.2, EN 719 should be met as demonstrated by the European Welding Engineer (EWE) or International Welding Engineer (IWE) qualification. Professional Membership of The Welding Institute (UK) is desirable and a minimum of 5 years relevant experience in the pipeline welding or fabrication industry is essential.

Welding inspectors

Competent and certificated welding inspection personnel shall be employed in sufficient numbers to ensure that welding related activities are adequately inspected. Welding Inspectors shall have a sound knowledge of welding processes and their application to pipeline welding, and possess the knowledge and skills to carry out the tasks given in the approved Quality Plan, including those necessary for the following: -

Conduct of routine inspections and checks on site or at suppliers in a systematic manner

-

Production of accurate records and reports

Welding Inspectors shall hold current certification to any of the following standards as a minimum: -

CSWIP (TWI, UK) – Welding Inspector

-

BGAS-CSWIP (TWI, UK) – Welding Inspector

-

PCN (BINDT, UK) – Weld Inspection Level 2

-

AWS QC1 (1996 or later edition) – Certified Welding Inspector (CWI)

Alternative Welding Inspector certification is unacceptable unless approved by BP. A Senior Welding Inspector shall be employed to coordinate and supervise the work of the welding inspectors. The role of Senior Welding Inspector requires at least 10 years relevant experience and sound knowledge of welding processes and their application. Formal engineering training through apprenticeship and technical college education are required. Senior Welding Inspectors shall hold current certification to any of the following standards as a minimum:

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1.8.3


-

CSWIP (TWI, UK) – Senior Welding Inspector

-

BGAS-CSWIP (TWI, UK) – Senior Welding Inspector (SWI) or Senior Pipeline Inspector (SPI)

-

PCN (BINDT, UK) – Weld Inspection Level 3

-

AWS QC1 (1996 or later edition) – Senior Certified Welding Inspector (SCWI)

NDT personnel

NDT personnel shall hold current Level 2 certification (or equivalent), specific to weld testing, for the appropriate NDT methods to any of the following standards as a minimum: -

CSWIP (TWI, UK)

-

BGAS-CSWIP (TWI, UK)

-

PCN (BINDT, UK)

-

ACCP (ASNT)

-

SNT-TC--1A (ASNT)

NDT personnel certificated to the requirements of a Written Practice under the rules of SNT-TC-1A shall not be used, unless the Written Practice and the personnel certification has been reviewed and accepted by BP for the specific work. Personnel engaged in AUT shall be qualified in accordance with GP 43-34. 1.9

Abbreviations and acronyms The following abbreviations and acronyms are used in this GIS: ACCP

ASNT Central Certification Program

AUT

Automatic Ultrasonic Testing

BAM

Federal Institute for Materials Research and Testing (Germany)

BGAS-CSWIP Personnel

British Gas Approval Scheme – Certification Scheme for Welding and Inspection

BINDT

British Institute of Non-Destructive Testing

CEIIW

Carbon equivalent (IIW formula)

C Eng

Chartered Engineer (UK)

CP

Cathodic protection

CRA

Corrosion resistant alloy

CSWIP

Certification Scheme for Welding and Inspection Personnel

CTOD

Crack tip opening displacement

CVN

Charpy V-notch

Dipl Ing

Diploma Ingenieur (Europe)

ECA

Engineering Critical Assessment

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FCAW

Flux-cored arc welding

GMAW

Gas-metal arc welding

GS-FCAW

Gas-shielded flux-cored arc welding

GTAW

Gas tungsten arc welding

HAZ

Heat affected zone

HV

Vickers hardness

ID

Internal diameter

IIW

International Institute of Welding

IQI

Image Quality Indicator

MDT

Minimum design temperature

MT

Magnetic testing

MUT

Manual ultrasonic testing

NDT

Non-destructive testing

NIST

National Institute of Standards and Technology (USA)

OD

Outside diameter

PCM

Cracking parameter (Ito-Bessyo formula)

PCN

Personnel certification in non-destructive testing

P-GMAW

Pulsed gas metal arc welding

PQR

Procedure Qualification Record

PT

Penetrant testing

pWPS

Preliminary welding procedure specification

RMS

Root mean squared

RT

Radiographic testing

SAW

Submerged arc welding

SCR

Steel catenary riser

SMAW

Shielded metal arc welding

SMYS

Specified minimum yield strength

SS-FCAW

Self-shielded flux-cored arc welding

SWE

Single wall examination Page 11 of 56

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SWV

Single wall viewing

TWI

The Welding Institute (UK)

UT

Ultrasonic testing

VT

Visual testing

WPQT

Welding Procedure Qualification Test

WPS

Welding procedure specification

2

Referenced publications Add The following standards contain requirements that, through reference in this text, constitute requirements of this GIS. For references below that are dated, subsequent amendments to, or revisions of, any of these publications do not apply, although parties to agreements based on this GIS are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. For references below that are undated, the latest edition of the referenced standards applies.

API Add Q1

Specification for Quality Programs for the Petroleum, Petrochemical and Natural Gas Industry

ASTM Add A370 E23 E92 E1815

Standard Test Methods and Definitions for Mechanical Testing of Steel Products Standard Test Methods for Notched Bar Impact Testing of Metallic Materials Standard Test Methods for Vickers Hardness of Metallic Materials Standard Test Method for Classification of Film Systems for Industrial Radiography

AWS Add D1.1/D1.1M A4.3 C5.3 A5.32

Steel Structural Welding Code Determination of Hydrogen Content Produced by Arc Welding Recommended Practices for Air Carbon Arc Gouging and Cutting Specification for Welding Shielding Gases

BSI Add BS 4515-1

Specification for Welding of Steel Pipelines on Land and Offshore – Part 1: Carbon and Carbon Manganese Steel Pipelines

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BS 7448-1 BS 7910


Fracture mechanics toughness tests. Part 1. Method for the determination of KIC, critical CTOD and critical J values of metallic materials Guide on methods for assessing the acceptability of flaws in metallic structures

Add

BP GIS 43-311 GIS 43-312

GIS 43-313 GIS 43-317 GP 18-02 GP 43-34

Guidance on Industry Standard for Manufacture of Longitudinal or Helical Seam Submerged Arc Welded Linepipe in Grades up to X80 Guidance on Industry Standard for Manufacture of High Frequency Induction (HFI) or Electric Resistance Welded (ERW) Linepipe in Grades up to X70 Guidance on Industry Standard for Manufacture of Seamless Linepipe in Grades up to X80 Guidance on Industry Standard for Bends, Fittings, Flanges, and Wyes Guidance on Practice for the Storage and Control of Welding Consumables Guidance on Practice for Automatic Ultrasonic Testing of Pipeline Girth Welds

Canadian Standards Association (CSA) CSA Z245.1 CSA Z662

Steel Line Pipe Oil and Gas Pipeline Systems

European Standard (EN) EN 439 EN 719 EN 875 EN 1011-2 EN 10045-1 EN 10204 EN 10208-1 EN 10208-2 EN 14717

Welding consumables – Shielding gases for arc welding and cutting Welding coordination. Tasks and responsibilities Destructive tests on welds in metallic materials - Impact tests - Test specimen location, notch orientation and examination Welding recommendations for welding of metallic materials Part 2: Arc welding of ferritic steels Charpy impact test on metallic materials - Part 1: Test method (V- and U-notches) Metallic products - Types of inspection documents Steel pipes for pipelines for combustible fluids. Technical delivery conditions. Pipes of requirement class A Steel pipes for pipelines for combustible fluids. Technical delivery conditions. Pipes of requirement class B Welding and allied processes – Environmental check list

International Organisation for Standardisation (ISO) ISO 148 ISO 2504 ISO 3183 ISO 3690

Steel - Charpy impact test (V-notch) Radiography of welds and viewing conditions for films - Utilization of recommended patterns of image quality indicators (I.Q.I.) Petroleum and natural gas industries – Steel pipe for pipeline transportation systems Welding and allied processes - Determination of hydrogen content in ferritic steel arc weld metal

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ISO 5580

Non-destructive testing - Industrial radiographic illuminators - Minimum requirements Metallic materials – Vickers hardness test – Part 1: Test method Quality management systems - Requirements Quality management – Guidelines for quality plans Non-destructive testing - Industrial radiographic films – Part 1: Classification of film systems for industrial radiography Non-destructive testing of welds – Radiographic testing of fusion-welded joints Non-destructive testing of welds – Magnetic particle testing Non destructive testing of welds – Ultrasonic testing of welded joints Petroleum, petrochemical and natural gas industries - Sector-specific quality management systems requirements for product and service supply organizations

ISO 6507-1 ISO 9001 ISO 10005 ISO 11699-1 ISO 17636 ISO 17638 ISO 17640 ISO TS 29001

UK regulations SI 1999 No. 3232

Ionising Radiation Regulations 1999 Statutory Instrument 1999 No. 3232 Work with ionising radiation - Ionising Radiations Regulations 1999 Approved code of practice and guidance (UK HSE)

3

Definitions of terms

3.2

Definitions

3.2.3

Company

Modify to Read BP plc or its authorised representative 3.2.4

Contractor

Modify to Read A contractor responsible to BP for construction (including welding) of the pipeline Add 3.2.21

Arc Energy

The unfactored energy input calculated from the current, voltage and travel speed. Note: Heat input requires an efficiency factor dependant on the welding process. 3.2.22

BP

BP plc, an associate or subsidiary of BP, or other organisation as defined in the Conditions of Contract on a project. 3.2.23

Lot

A single heat of filler wire, a single blend of flux, or for covered electrodes or cored wire, the combination of a single heat of cored wire with a single dry blend of flux cover or core.

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3.2.24


Quality Plan Document specifying which procedures and associated resources shall be applied by whom and when to a specific project, product, process or contract. Note: Guidance for the production of Quality Plans is given in ISO 10005.

4

Specifications

4.1

Equipment Add Welding power supply voltage and amperage meters shall be calibrated. Independent calibrated instrumentation shall be provided to measure relevant parameters during production. NDT equipment shall also be calibrated. Certificates showing that equipment calibration is valid for the period of use shall be available. The manufacturer, model and type of equipment shall be identified in the Procedure Qualification Record (PQR). SMAW electrode holders shall be fully insulated. Welding return cables connections shall be of sufficient cross-sectional area to prevent concentration of current and shall be securely attached to prevent arc burns.

4.2

Materials

4.2.1

Pipe and fittings

Add c.

ISO 3183

d.

EN 10208

e.

CSA Z245.1

The requirements given apply to materials that comply with any of the standard specifications listed in a & b (in API 1104) and c to e above. Note that API 5L is supplemented by BP GISs and that BP supplementary requirements may be applied to any of the above specifications. Other material specifications may be used if required by statutory regulations of the countries in which the pipeline will operate. 4.2.2

Filler metal

4.2.2.1

Type and size

Add In principle, the yield strength of the weld metal should be selected to ensure that the yield strength of the deposited pipeline girth welds overmatches the actual yield strength of the parent pipe material. Additional guidance will be provided by the pipeline designer. The deposited weld metal shall also meet the specified ductility, toughness, and limiting hardness criteria in accordance with the pipeline design and with this GIS. Add 4.2.2.1.1

Limitations of use for cellulosic electrodes

Cellulosic coated electrodes shall not be used for:

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-

Pipe grades and thicknesses beyond those shown in Table A

-

Pipelines subject to high strain (e.g. reeled pipelines)

-

Strain based design pipelines

-

The welding of fittings, flanges and valves

-

Fillet welding (e.g. for anode doubler plate attachment)

In applications in which cellulosic SMAW consumables are being evaluated for use, the possibility of employing low hydrogen vertical down electrodes shall be considered. Cellulosic electrodes shall neither be baked nor dried and shall be used straight from the original packaging. Table A - Grade and thickness limits for cellulosic electrodes (a,b)

Pipe Grade (API 5L)

Pipe Grade (ISO 3183) (EN 10208) (CSA Z.245)

Maximum Wall Thickness

< X65

< L450

X70

L485

5/8” (approx 16 mm) with E8010 fill passes 3/8” (approx 10 mm) with E9010 fill passes

X80

L555

Root & hot pass only

> X80

> L555

3/4” (approx 19 mm)

Not permitted

a. E6010 or E6011 electrodes may be used for root pass welding provided sufficient overall weld strength and toughness is obtained. b. Preheat shall be applied to cellulosic welds (see 5.3.2.13 and 7.11.1).

4.2.2.1.2

Consumable selection for root welding

In some instances it may be necessary to select a root welding consumable having a specific chemical analysis in order to provide resistance to preferential weld metal corrosion. The pipeline designer will provide advice on any such requirement. If a weld metal composition is specified, then one root weld metal chemical analysis shall be conducted for each WPS and each weld repair procedure to check that the required composition has been achieved. 4.2.2.2

Storage and handling of filler metals and fluxes

Add The storage and handling of welding consumables shall be in accordance with GP 18-02. A detailed consumable storage and handling plan shall be submitted for BP review and approval. Add 4.2.2.3

Consumable lot testing by supplier*

*Note: Some standards, project specifications and/or consumable suppliers may refer to “Consumable Batch Testing”. Each lot of welding consumables shall have a consumable manufacturer’s certificate conforming to the relevant ISO, AWS or EN filler metal specification. The testing of each lot shall include actual deposited weld metal chemical composition, tensile and Charpy impact tests; refer to BP GP 18-02.

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For low hydrogen SMAW consumables, manufacturer’s certificates shall include averagediffusible-hydrogen level as determined and reported in accordance with ISO 3690 or ANSI/AWS A4.3. Certificates shall comply with BP GP 18-02 and EN 10204 type 3.1.b. SAW wire shall be tested in combination with the same brand and classification of flux as that to be used during production welding. The consumable certificates shall be examined to verify that the same weld properties can be expected for the production welds as those obtained during weld procedure testing. 4.2.2.4

Additional lot testing

Only the lots of consumables mechanically tested during qualification of the weld procedure shall be used for production welding of the following pipeline types: -

If the NDT acceptance criterion has been established by an ECA

-

For pipe grades of X65 and above

-

If consumables with an AWS “G” designation are used, e.g. E8010-G or ER70S-G

Testing may be conducted to gain approval for additional lots of consumables. Testing shall be undertaken on a weld made in accordance with the production WPS and shall include: -

2 all-weld tensile tests

-

2 sets of weld metal Charpy impact tests

-

1 macro-section and hardness survey sampled from the 3 o’clock position

-

1 set of weld metal CTOD tests

The testing shall be in accordance with 5.6. The results shall meet the levels required for the relevant weld procedure(s) and, if applicable, the ECA. 4.2.3

Shielding gases

Add 4.2.3.3

Compliance

Shielding gases shall meet BS EN 439 or AWS A5.32. They shall be pre-mixed and bottled by the supplier and shall have certificates of compliance. The certificates shall show the composition and dew point. Subject to BP approval, Ar/CO2 gases may be mixed at site. Add 4.3

Minimum design temperature (MDT) Unless otherwise specified in the contract, the MDT shall be 0°C (32°F).

5

Qualification of welding procedures for welds containing filler-metal additives

5.1

Procedure qualification

Add 5.1.1

General

Preliminary Welding Procedure Specifications (pWPSs) shall be submitted for BP agreement before commencement of the Welding Procedure Qualification Tests (WPQTs).

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Welding procedures, including fillet welds and repair procedures, shall be qualified by visual examination, NDT, and mechanical testing as specified in this GIS. Welding, NDT and mechanical testing of the WPQT welds shall be witnessed by BP or an approved third party. The witnessing of mechanical tests shall include the positioning of the notches for Charpy and CTOD tests. A WPS written with more than one supporting Procedure Qualification Record (PQR) shall not permit optional processes, but shall uniquely specify the process for each pass. 5.1.2

Welding procedure parameters

During weld procedure qualification, relevant procedure data, irrespective of whether the item is a listed essential variable, shall be captured and recorded. Sufficient information shall be recorded to allow full replication of the procedure qualification welds. A record of the data shall be kept for the purpose of aiding production and to assist with the diagnosis of problems, but need not be formally entered on to the PQR, e.g. GMAW machine ‘slope-in’ settings. The methods of measuring the welding parameters and the records to be kept shall be agreed with the BP Welding Engineer. Following qualification, the pWPS shall be revised to reflect the parameters recorded during qualification. The revised WPS values for current, voltage, and travel speed for each pass shall be either: (i)

within the range recorded during WPQT. Transient or anomalous values shall not be used to establish the range, or

(ii) the mean value +/–10%. The arc energy shall be calculated using the recorded values of current, voltage, and travel speed without the addition of a percentage. The final WPS shall state parameters for each pass. However, if fill passes (i.e. passes other than root, hot pass, and cap) have similar values, the parameters may be combined on the WPS. If a welding consumable or group of consumables is qualified to weld several different components or pipe sizes, every effort should be made to ensure that the parameters specified on the individual WPSs are common across the group of WPSs. 5.2

Record Modify First Sentence to Read The details of each procedure shall be recorded Add Forms used to record WPS and WPQT details shall contain the relevant information. The format shall be subject to approval by BP. The PQR documentation package for each WPS shall comprise: a.

As-run records

b.

NDT results

c.

Mechanical test results and macrographs

d.

Consumable certification

e.

Parent material certification

The following data shall also be available if requested by the BP Welding Engineer: f.

Calibration certificates for equipment and measuring devices

Page 18 of 56

21 April 2006


g.

SNT (ASNT) Written Practice (if applicable)

h.

Welding Inspector and NDT personnel certification

i.

NDT procedure qualification records

j.

Testhouse approval certification

The approved WPSs and PQR packages shall also be available in a good quality electronic format. 5.3

Procedure specification

5.3.1

General

Add The relevant BP approved WPSs shall be displayed at each work location and shall be readily available to each welder. 5.3.2

Specification information

5.3.2.2.

Pipe and fitting materials

Modify to Read Pipe, valves, flanges, and fittings from different manufacturers, or manufactured from materials supplied from different sources or in different supply conditions, shall require separate procedure qualification as detailed in 5.4.2.2, unless a material grouping is approved by BP. The manufacturer(s) shall be noted on the WPS. 5.3.2.3

Diameters and wall thicknesses

Modify to Read The ranges of pipe diameters and wall thicknesses over which the procedure is approved are identified in Table B unless alternative ranges are agreed by BP. Table B - Diameter and test pipe thickness range of approval Test Pipe Diameter (in)

(mm)

(mm)

D < 2.375

D < 60.3

< 2.375

< 60.3

2.375 < D < 12.75

60.3 < D < 323.9

2.375 to 12.75

60.3 to 323.9

12.75 < D < 24.0

323.9 < D < 610

12.75 to 24.0

323.9 to 610

D > 24.0

D > 610

> 24.0

> 610

Test pipe thickness = t

5.3.2.4

Range of Approval (in)

0.75t to 1.5t

Joint design

Add The use of permanent or consumable backing rings is not permitted. An exception is the outer pipe welds in a pipe-in-pipe system. Non-consumable temporary backing as an integral permanent feature on an internal clamp will be permitted subject to satisfactory demonstration of the process.

Page 19 of 56

21 April 2006

5.3.2.5


Filler metal and number of beads

Add The brand name, electrode or wire name, designation and ISO/AWS/EN welding consumable classification shall be stated in the PQR. 5.3.2.6

Electrical characteristics

Add The following parameters shall be specified on WPSs: a.

Welding current (including pulse rate, pulse shape or dwell time, and max/min current for pulsed welding procedures)

b.

Diameter of electrodes or welding wires

c.

Wire-feed speed (and pulse rate or frequency for pulsed wire procedures)

d.

Arc energy for each pass. For multiple (electrically isolated) tandem electrode welding processes, e.g. SAW or P-GMAW, the effective arc energy per pass shall be calculated as the sum of the individual arc energies for each electrode. For pulsed procedures, the effective arc energy shall be calculated on the basis of RMS values. Voltage and current shall be determined with calibrated meters and recorded for each pass during WPQT welding using suitable BP approved data monitoring equipment.

If applicable, the following parameters shall be specified in the WPS: e.

Type, diameter and angle of tip for GTAW tungsten electrodesSAW GMAW FCAW

f.

Hot wire diameter, feed speed, current, and voltage

g.

Head angle, electrode spacing from top-dead centre and direction of rotation for 1G-rotated welding

h.

Contact tip to workpiece distance

i.

Electrode spacing and individual angles relative to pipe surface (for welding with multiple electrodes)

j.

Torch separation and angle for multiple torch welding

k.

Torch oscillation frequency for mechanised (automatic) welding

l

Shroud (gas-cup) diameter

fcaw gmaw SAW

FCAW GMAW saw

The welding unit, power supply type, manufacturer, model number, and software version number shall be stated for automatic, mechanised, or semi-automatic welding procedures. 5.3.2.8

Position

Add The welding position shall be stated on the WPS and PQR documents. 5.3.2.10

Time between passes

Add The time between completion of the root bead and commencement of deposition of the hot-pass shall be not greater than that qualified in the WPQT and should not be greater than 10 minutes. If cellulosic welding is used, the second run (hot-pass) shall be deposited immediately after completion of the root bead.

Page 20 of 56

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5.3.2.11


Type and removal of line-up clamp

Add For pipe-to-pipe joints over 150 mm (6 in) diameter, an internal line-up clamp should be used. If it is agreed by BP that this is impracticable, e.g. for tie-ins, an external line-up clamp shall be used. If an internal line-up clamp is used, the root run shall be 100% complete before the clamp is removed. If an external line-up clamp is used, the root run shall be at least 50% complete before the clamp is removed. In either case, the pipes on both side of the joint shall not be raised, lowered or otherwise moved until both the root and the second weld pass (hot pass) have been completed, unless it can be demonstrated to the satisfaction of BP that the root run alone is adequate to resist the deformation. For SMAW welding using cellulosic coated electrodes, the hot pass shall always be completed before the pipe is moved. 5.3.2.13

Pre- and post-heat treatment

Add As a minimum, a preheat temperature shall be selected to ensure that: a.

The pipe is dry before welding

b.

The metal temperature is greater than 30°C (86°F)

c.

The metal temperature is greater than 50°C (122°F) if moisture is present on the pipe and/or if ambient temperatures are below 5°C (41°C)

d.

The hardness requirements of 5.6.8.3 are met for the weld metal and HAZ

e.

The weld metal is not at risk of hydrogen cracking (for cellulosic welds see Table C for guidance on minimum preheat levels)

f.

Sufficient heat is present to prevent cold (hydrogen) cracking in the HAZ Note: Guidance for the avoidance of HAZ cracking is given in EN 1011-2, AWS D1.1/D1.1M Annex XI, and BS 4515-1 Annex E. Table C - Minimum preheat levels for SMAW (cellulosic) welds

Filler Grade (AWS Designation)

Wall Thickness (in)

E6010

(mm)

Minimum Preheat Temperature (°F)

(°C)

< 0.4

< 10

122

50

0.4 < 0.6

10 < 15

167

75

> 0.6 < 0.8

> 15 < 20

212

100

E7010 & E8010

< 0.4

< 10

176

80

0.4 < 0.6

10 < 15

212

100

> 0.6 < 0.8

> 15 < 20

248

120

E9010

< 0.4

< 10

212

100

The preheat temperature shall not be lower than that recorded during WPQT welding. The interpass temperature shall not be less than the preheat temperature and shall not exceed the highest value recorded during WPQT. In no case shall the interpass temperature exceed 300°C (572°F). The preheat and interpass temperatures shall be measured in accordance with 7.11.1.

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If any form of post-weld heat treatment or delayed cooling of the weld is to be used, it shall be specified in the WPS. If the weld is to be cooled rapidly to allow immediate AUT, then this shall be simulated during WPQT. Assisted cooling shall not commence until the weld temperature has cooled without interference to below 400°C (750ºF). 5.3.2.14

Shielding gases and flow rate

Modify to Read Shielding gas type, composition, and flow rate (for each torch in multi-torch systems) shall be specified in the WPS. Add 5.3.2.17

Bead map

A sketch of the weld cross-section showing the bead sequence shall be made for each WPS. If bead deposition is by a weaving technique, this shall be designated on the WPS. Low hydrogen SMAW electrodes shall not be weaved by more than 3 times the nominal electrode core wire diameter. 5.3.2.18

Period of validity for welding procedures

For new pipeline construction projects, new WPSs shall be prepared and qualified. For the purposes of undertaking further work to an existing pipeline, a WPS may remain valid indefinitely. The BP Welding Engineer shall be consulted before re-using the WPS. 5.4

Essential variables

5.4.1

General

Add An approval of a WPS obtained by a contractor is valid in workshops or sites of that contractor under identical or equivalent technical and quality control. The validity shall be subject to the approval of the BP Welding Engineer. Welding procedures shall not be transferred from one contractor or sub-contractor to another without requalification. 5.4.2

Changes requiring requalification

5.4.2.1

Welding process or method of application

Add Any change from a single torch per motorised head to multiple torches, or vice-versa, shall constitute an essential variable. Any change of wire delivery system for SAW or mechanised (automatic) GMAW/ GTAW, including from single to double or multiple wires and/or from cold to hot-wire systems, or vice versa, shall constitute an essential variable. Add 5.4.2.1.1

Line-up clamp

A change from internal to external line up clamp, or vice-versa; or, from internal clamp without an internal welder to an internal clamp incorporating an internal welder, shall constitute an essential variable.

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Removal of a line-up clamp at an earlier stage than qualified in the WPQT constitutes an essential variable. 5.4.2.1.2

Weld or joint backing

Use or removal of copper backing rings or shoes, or combination of these, shall be considered an essential variable. 5.4.2.1.3

Number of welders or welding operators

The number of welders shall be at least as many as during welding of the test piece and shall be considered as an essential variable for each pass. 5.4.2.1.4

Interpass cleaning

The method of interpass cleaning shall be considered an essential variable. 5.4.2.2

Base material

Modify to Read Base material grouping by strength shall only be allowed for materials with an SMYS less than or equal to 42,000 psi (290 MPa); but, for all grades of material, the following shall constitute essential variables: a.

Change of manufacturing facility for strip, billet, plate, pipe or forging

b.

Change of steel making, plate rolling, forging or pipe manufacturing process

c.

For grades up to and including X80, a change of composition resulting in a change of greater than ±0.03CEIIW or greater than ±0.02Pcm value. For sour service pipelines, a change in composition resulting in greater than +0.01 or –0.03CEIIW or greater than +0.01 or –0.02Pcm value.

CE IIW = C +

Pcm = C + d. 5.4.2.3

Mn Cr + Mo + V Ni + Cu + + 6 5 15

Si Mn + Cu + Cr Ni Mo V + + + + + 5B 30 20 60 15 10

For grades above X80, composition limits will be advised on a project by project basis.

Joint design

Add For narrow gap welding, e.g. mechanised (automatic) GMAW, any change in bevel angle beyond ±1°, root face beyond ±50% or root gap +0.5 mm (0.02 in) constitutes an essential variable. Any weld preparation with an included angle of less than 20° shall be considered to be narrow gap welding. For other welding, any changes in bevel angle by more than ±5°, or variation in root gap/root face by more than ±50%, constitutes an essential variable. Note: For pipe grades above X80 (L555), it may be necessary to impose more stringent limits on the joint design for mechanised (automatic) welding than those quoted above as minor changes can result in significant differences in mechanical properties of the girth welds.

Page 23 of 56

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5.4.2.4


Position

Add A change of welding position shall constitute an essential variable. Welding positions 5G and 2G shall be qualified separately. 6G qualification shall be required if the angle of the pipe is between 25° and 65° to the horizontal. 5.4.2.5

Wall thickness

Modify to Read Any change outwith the grouping ranges of pipe by diameter and wall thickness designated in 5.3.2.3, shall constitute an essential variable. 5.4.2.6

Filler metal

Modify to Read The following changes in filler metal constitute essential variables: a.

Any change in filler metal designation, filler metal manufacturer, manufacturing location or brand name

b.

Any change in welding consumable or size

c.

Lot testing as per 4.2.2.3 is required

The compatibility of the base material and the filler metal should be considered from the standpoint of mechanical properties. 5.4.2.7

Electrical characteristics

Add Any change in the following shall be considered essential variables:

5.4.2.8

a.

The welding current, arc voltage and travel speed outside that recorded on the WPS

b.

For pulsed current welding the pulse rate, pulse shape, and max/min current recorded on the WPS

c.

For GMAW, cored wire welding and hot wire GTAW any change of wire feed speed outwith the range qualified

d.

Arc energy for each pass outside of the range recorded on the WPS

e.

Head angle, electrode spacing from top dead centre and direction of rotation for 1GRotated welding

f.

Electrode spacing for welding procedures utilising multiple electrodes, e.g. tandem-wire SAW, or mechanised (automatic) tandem wire or twin torch processes

g.

Diameter of electrodes or welding wires

h.

For semi-automatic and mechanised (automatic) welding, the welding unit, power supply type, manufacturer, model number and software version number

Time between passes

Add If using cellulosic electrodes, the time lapse between the start of the root bead and the start of the second bead shall not exceed the time lapse recorded during welding of the test piece.

Page 24 of 56

21 April 2006

5.4.2.10


Shielding gas and flow rate

Add Any change of shielding gas flow rate greater than ±15% of that qualified shall constitute an essential variable. 5.4.2.11

Shielding flux

Add For pipeline grades greater than X52, any change of shielding flux manufacturer, manufacturing location, brand or type constitutes an essential variable. Any change of flux for pipeline grades X52 and below shall be subject to the agreement of the BP Welding Engineer. 5.4.2.12

Speed of travel

Add A change in speed of travel beyond the range on the qualified WPS constitutes an essential variable. 5.4.2.13

Preheat

Add Any change in the preheat application method shall constitute an essential variable. Add 5.4.2.15

Arc energy per pass

Any change in arc energy outside of the range in the approved WPS shall constitute an essential variable. 5.4.2.16

Interpass temperature

An increase in the specified interpass temperature shall constitute an essential variable. The use of rapid cooling of welds constitutes an essential variable unless simulated in the WPQT. 5.5

Welding of test joint—butt welds

Add 5.5.1

Test pipe for WPQT

The WPQT shall simulate the production welding of the pipelines and shall be undertaken as far as practicable, under site ambient conditions. For land pipelines, lifting and lowering off shall be simulated using full pipe lengths. If an internal line-up clamp will be used in production welding, the length of the nipples used in the WPQT shall be sufficient to accommodate the full length of the clamp. The minimum length of any nipple piece used during qualification should be 1 m (3.3 ft) or 1.5 pipe diameters whichever is the greater. The minimum length of test rings for the WPQT of fittings and flanges shall be subject to agreement with BP.

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5.6

Testing of welded joints—butt welds

5.6.1

Preparation

Add Reference Figure 3 and Table 2, in accordance with this GIS The blanks from which the mechanical test pieces are machined may be cut from the qualification weld using oxy-fuel gas cutting, but its dimensions shall be sufficient to allow the material of the final machined test piece to remain unaffected by the heat from the cutting operation. Test specimens shall not be subjected to any elevated temperature degassing treatment. Add 5.6.1.1

Non-destructive testing of WPQT welds

WPQT welds shall be visually examined (VT) as soon as possible after completion of welding with 100% coverage of weld surfaces. WPQT welds shall meet the same requirements for weld profiles and VT as those specified for production welds. The full circumference of WPQT welds shall be examined by radiographic testing (RT), ultrasonic testing (AUT or MUT), and magnetic particle testing (MT). For WPQT welds, there shall be a minimum delay time as specified in Table D between completion of welding and nondestructive testing of the welds. Table D - Specified minimum delay time before NDT for WPQT welds WPQT Welds in API/ISO Pipe Grades

Welding Process

Minimum Delay Before NDT

< API X70 / ISO L485

Any process except cellulosic SMAW

24 hours

a

a

< API X70 / ISO L485

Cellulosic SMAW

> API X70 / ISO L485

Any welding process

48 hours 72 hours

Welds made with cellulosic root/hot pass only may be inspected after 24 hours.

Acceptance by BP shall be required before sectioning of WPQT welds for mechanical testing. The NDT procedures for WPQT welds shall be qualified and subject to approval by BP. 5.6.1.2

Mechanical testing

Mechanical testing shall be performed by a certified testing laboratory approved by BP. Test specimens shall be taken from pipeline WPQT butt welds as shown in Figure 3. Repair weld mechanical testing locations and specimen types/ numbers shall be in accordance with Table H. Test specimens not shown in Figure 3, e.g. CTOD test pieces, may be taken from any position around the weld where spare material is available, but the exact locations should be agreed in each instance with the BP Welding Engineer. More than one weld may be required to provide sufficient material for testing. Table 2 shows the type and number of test specimens required. 5.6.1.3

Test temperature

Destructive testing shall be performed at ambient temperature, except for impact testing (see 5.6.6.3) or CTOD testing (see 5.6.10). For design service temperatures above 100°C (212°F), elevated temperature transverse and weld tensile testing shall be undertaken. The test temperature, extent of testing and required strengths shall be specified on a project specific basis.

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5.6.1.4


Repair of WPQT welds

Weld repairs to WPQT welds are not permitted, except if the purpose is to qualify a repair procedure. 5.6.2

Tensile-strength test

5.6.2.1

Preparation

Add Preparation of the tensile test piece shall be as per Figure 4, except that internal and external weld reinforcement shall be removed before testing. The position of failure shall be recorded, i.e. weld metal, HAZ or base metal.

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Modify Figure 3 to Show Figure 3 - Location of test pieces from a butt weld in pipe

5 3

6

1

2

6

4

5 4

2

< 60.3mm (2.375”)

> 114.2mm (4.500”)

5 6

but < 323.9mm (12.750”)

3

5

2 5

4

2

1

3

5 5

6 3

2

5

1

2

4

> 60.3mm (2.375”) but

6 1

3

4

< to 114.3mm (4.500”)

2

3

Also, < 114.3mm (4.500”) when

4

5

wall thickness > 12.7mm (0.500”) 4

2

3

Greater than 323.9mm (12.75”)

5

5 6

3

4

2

3

1 5

2

4

1 Key: 1)

Face or side bend

2)

Transverse tensile

3)

Root or side bend

4)

Nick-break

5)

Macrosection

6)

Charpy V-Notch

NOTE: Test specimens not shown in Figure-3, e.g. CTOD test pieces, may be taken from any position around the weld where spare material is available. More than one weld may be required to provide sufficient material for testing.

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Modify Table 2 to Read Table 2 - Type and number of test specimens (a) for procedure qualification test Number of Specimens for Wall Thickness ≤ 12.7 mm (0.500 in) OD of Pipe mm (in)

Tensile Strength (Cross Weld Tensile)

All-Weld Metal Tensile (c)

Nick Break (d)

Root Bend

Face Bend

Side Bend

Charpy Impact Tests (set of 3) (e)

Macro/ HV10

CTOD (set of 3 ) (f & g)

<60.3 (<2.375) (b)

2

0

2

2

0

0

0

3

3

60.3-114.3 (2.3754.500)

2

0

2

2

0

0

2

3

3

>114.3-323.9 (4.500-12.750)

2

1

2

2

2

0

4

3

3

>323.9 (>12.750)

4

1

4

4

4

0

4

3

3

OD of Pipe mm (in)

Tensile Strength (Cross Weld Tensile)

All-Weld Metal Tensile (c)

Nick Break (d)

Root Bend

Face Bend

Side Bend

Charpy Impact Tests (set of 3) (e)

Macro/ HV10

CTOD (set of 3) (f & g)

<114.3 (4.500)

2

1

2

0

0

2

2

3

3

>114.3-323.9 (>4.500-12.750)

2

1

2

0

0

4

4

3

3

>323.9 (>12.750)

4

1

4

0

0

8

4

3

3

Number of Specimens for Wall Thickness > 12.7 mm (0.500 in)

NOTES: a Specimen locations shall be in accordance with 5.6 and Figure 3. b One nick-break and one root-bend specimen shall be taken from each of two test welds, or for pipe less than or equal to 34 mm (1.315 in) diameter, two full section tensile strength specimens shall be taken. c If an ECA is to be used for defect acceptance levels, three all-weld metal tensile specimens shall be taken. d. Nick breaks are not required for mechanised (automatic) welding. e Charpy impact tests shall comprise weld metal and fusion line specimens machined from the pipe outside diameter. Pipes with wall thickness > 20 mm shall have additional specimens machined from the ID .Additional sets of Charpy Impact specimens may be required by the BP welding engineer, e.g. if very thick pipe is to be utilised or the combination of processes or consumables have not been adequately sampled by the specified locations. f CTOD tests shall comprise a minimum of one set of weld metal and two sets of HAZ samples (see paragraph D.4 of Appendix D). g CTOD tests are only required for pipelines with ECA based acceptance criteria or if required by the pipeline designer.

5.6.2.3

Requirements

Modify to Read The results of transverse weld tensile tests shall meet or exceed the specified requirements for the pipe (base metal) with respect to specified tensile strength. Transverse weld tensile specimens shall fail at a location within the HAZ or base metal. If base metals of different strength levels are used, then acceptance criteria shall be based on the lower strength base metal.

Page 29 of 56

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Add 5.6.6

Charpy V notch testing

5.6.6.1

Scope

WPQT butt welds shall be subjected to Charpy V notch impact testing. 5.6.6.2

Preparation

The test pieces shall be prepared and tested in accordance with ISO 148, EN 10045-1 and EN 875 or ASTM A370 and E23. A set of Charpy impacts shall comprise three specimens. Sets of Charpy specimens shall be taken from the locations shown in Figure 3. Specimens shall be notched with the axis of the notch perpendicular to the pipe surface. The position of the notch for each set shall be as depicted in Figure A. Full size specimens shall be used if possible. 5.6.6.3

Method

The impact test temperature shall be the minimum design temperature when the following conditions apply: -

The minimum design temperature is minus 10°C (14°F) or higher

-

The wall thickness is 25 mm (1 in) or lower

-

The material SMYS is 555 N/mm2 (80 ksi) or lower

In addition to the above, for gas pipelines the impact test temperature shall be no higher than minus 10°C (14°F). Test temperatures for welds outside of the above conditions shall be advised by BP. Figure A - Charpy V notch locations

A(i) Weld Centreline

A(ii) Fusion Line

Page 30 of 56

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NOTES: 1 Specimens shall be positioned between 1 – 2 mm from the pipe outer surface. Additional specimens for thicknesses greater than 20 mm shall be positioned within 1 – 2 mm from the inner surface. 2 Fusion line Charpy specimens shall sample 50% weld metal and 50% HAZ.

5.6.6.4

Requirements

The Charpy impact values shall meet or exceed the values given in Table E. Table E - Charpy impact test requirements Grade

Minimum Average Energy

Minimum Individual Energy

ft lbs

J

ft lbs

J

< X80

< L555

37

50

30

40

X80

L555

44

60

33

45

> X80

> L555

To be advised

For specimens below 10 mm in thickness, the energy requirement shall be reduced pro rata, e.g. a 7.5 mm specimen shall achieve 75% of the required full size value. The ductile shear area shall exceed 50%. Individual samples may be replaced if there is evidence of a weld defect on the fracture surface. Re-testing may be allowed following discussion with the BP Welding Engineer. Test results, including percentage ductile shear area, shall be recorded. 5.6.7

Macro-section

5.6.7.1

Method

Macro-sections shall be extracted from procedure qualification test welds at three locations approximately 90° apart. For welds containing any pass made in the 5G position, macrosections shall be extracted as close as practicable to the 12 o’clock, 3 o’clock and 6 o’clock positions. When girth welding seam-welded linepipe, an additional macro-section shall be extracted from the girth-weld at the T-intersection region between the girth weld and seam weld. Macro-sections shall be polished to a metallographic (1 µm) finish and etched in a 2-10% Nital solution, or other suitable BP approved etchant. The etched specimens shall be thoroughly examined at 10 times magnification. Original photo-macrographs of macro-sections at approximately 3 to 5 times magnification shall be included in the PQR documentation. 5.6.7.2

Acceptance criteria

When examined at 10 times magnification, the macro-section shall reveal: a.

No cracks

b.

Complete fusion between adjacent layers of weld metal and between weld metal and base metal

c.

Complete fusion at the root

d.

No lack of cross penetration

e.

No undercut (unless weld surfaces are to be ground smooth). If weld surfaces are to be ground smooth, minor undercut may be removed by the surface grinding operation. If the

Page 31 of 56

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undercut is of such depth that its removal would result in encroachment of the minimum specified thickness of the pipe, it shall be deemed unacceptable. f.

No excess cap reinforcement exceeding 1.6 mm (1/16 in) above the base metal surfaces for weld surfaces not specified to be ground smooth

g.

Weld reinforcement shall blend smoothly into the adjacent base metal

h.

No penetration of the root bead into the bore exceeding 3 mm (1/8 in). For pipe diameters less than 60 mm (2-3/8 in) this penetration shall not exceed 1.5 mm (1/16 in).

i.

At no point shall the weld surface, ID or OD, lie below the adjacent base metal

Any observed defects shall be within the limits given in Section 9. 5.6.8

Hardness test

5.6.8.1

Preparation

The hardness testing technique shall be the Vickers method with an applied load of 10 kg in accordance with ISO 6507-1 or ASTM E92. The hardness surveys shall be undertaken on each of the macro-section specimens specified in 5.6.7. For non-sour pipelines, surveys on the 12 o’clock and 6 o’clock macro-sections may be omitted. 5.6.8.2

Method

Each survey shall consist of three rows of indents. One traverse shall be located below the cap, one above the root (or internal surface) and one at mid-thickness. The positions are shown in Figure B. The mid-thickness traverse may be waived for single sided welds below 12.7 mm. The BP Welding Engineer may require additional hardness indent positions, e.g. if a consumable type has not been sampled by the specified three traverses. Figure B - Locations for hardness indents 1 - 2mm t/2

1 - 2mm

NOTES: 1. Parent material indentations shall be at least 20 mm from the fusion line. 2. The first HAZ indentation shall be placed as close to the fusion line as possible. Further indentations into the HAZ shall be separated by approximately 0.5 mm, however the minimum centre-to-centre separation requirement of 2.5 or 3 times the mean diagonal of the nearest indentation shall be maintained (ref. ISO 6507-1 and ASTM E92). 3. The same survey pattern shall be applied to double-sided welds.

The macrophotographs shall show the position of each hardness indent and shall be included in the PQR along with a tabulation or diagram showing the result and location of each indent. The maximum and minimum values shall be identified. 5.6.8.3

Requirements

The individual hardness values shall not exceed the values given in Table F.

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The parent material hardness values shall not exceed the values permitted in the relevant material specification. Table F - Maximum permissible weld and HAZ hardness values (HV10) Grade < X80

> X80

< L555

Location

Sour

Non-Sour SMAW Cellulosica

Other Processes 275

Inside Surface & Mid-Thickness

Weld

248

275

HAZ

248

275

275

Outside Surface

Weld

275

275

275

HAZ

275

325

350

> L555

b

To be advised

NOTES: a Use of cellulosic electrodes is limited to the applications shown in 4.2.2.1.1 b For grade X80 (L555), outside surface weld metal hardness levels up to 300HV10 are permitted

5.6.9

Weld metal tensile test (all-weld metal tensile test)

Weld metal tensile test specimens shall be in accordance with ASTM A370. For narrow gap welds in which the width of the weld bead is insufficient to permit a conventional all-weld metal tensile test piece to be prepared, the geometry of the test piece shall be agreed with BP. The longitudinal axis of the tensile test specimen shall coincide with the procedure qualification testweld axis. The tensile specimen shall be prepared by machining, and its size and location shall be such that the gauge length consists only of weld metal. The weld metal yield strength shall not be less than the SMYS of the pipe. Weld metal overmatching of the typical pipe yield strength is considered desirable. The weld metal strength, in relation to the actual pipe yield strengths, shall be considered if an ECA is used or the pipeline design requires this. 5.6.10

CTOD testing

Requirements concerning CTOD testing can be found in Appendix D. 5.7

Welding of test joints—fillet welds Add The tests specified in 5.8 do not provide comprehensive information on the mechanical properties of the joint. If mechanical properties are relevant to the application, then an additional qualification shall be made, e.g. a butt weld.

5.8

Testing of welded joints—fillet welds

5.8.1

Preparation

Add Two macro-sections shall be taken from the test weld at locations agreed with the BP Welding Engineer. The specimens shall be prepared and examined in accordance with 5.6.7. 5.8.2

Method

Add One of the macro-sections shall be subject to hardness testing. The test method shall be Vickers with an applied load of 10 kg in accordance with ISO 6507-1 or ASTM E92. The survey shall consist of two traverses with indentations as shown in Figure C.

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Figure C - Fillet weld hardness indent locations

1 – 2 mm

NOTE: Notes 1 and 2 from Figure B are applicable.

A macrophotograph shall show the position of each hardness indent and shall be included in the PQR along with a tabulation or diagram showing the result and location of each indent. The maximum and minimum values shall be identified. 5.8.3

Requirements

Add If the fillet weld is on the outside of the pipe wall and, therefore, not in contact with the process fluids, then the criteria given in Table F for outside surface shall apply.

6

Qualification of welders

6.1

General Add Welder qualification tests shall be carried out on full diameter project pipe nipples. Test welds shall be visually sealed at each end until at least the root bead and hot pass have been completed around the full circumference. Testing shall be witnessed by a BP representative or a BP approved third party inspector. Welders shall be qualified for each welding process that they will use in production. Welders shall complete at least 50% of the circumference for the passes they are being qualified for. For automatic, mechanised or semi-automatic welding, each welder shall be qualified for each type, manufacturer, and model number of the welding unit(s) and power supply to be used in production welding or for weld repair. Welders shall be qualified before welding on the pipeline. A welder who has satisfactorily completed a procedure qualification test is automatically qualified for that procedure. Previous welder qualification tests may be accepted by BP provided they are fully documented, supported by production records demonstrating satisfactory welder performance, and are less than 6 months old. These tests shall have been conducted utilizing a WPS substantially the same as that for the current work and, for automatic, mechanised or semi-automatic welding procedures, utilizing the same type, manufacturer, and model number of welding unit and power supply. Additionally, these tests shall have been conducted by the same fabrication contractor and witnessed by BP, or have been conducted by a BP approved independent testing laboratory. In addition to the practical welding test and before the commencement of production welding, welders shall be required to attend a briefing session arranged jointly with the BP Welding Engineer. This briefing shall detail the elements of good welding practice and the specification requirements applicable to production welding. These requirements shall be further emphasized

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during regular tool-box sessions and each welder shall be issued a card or booklet summarising these requirements. This card or booklet shall be available for reference at all times when welding. Any welder who, in the opinion of BP, is either consistently ignoring good welding practice or specification requirements or is responsible for a high level of repairs during production shall be removed from the work, and shall undergo a re-training programme approved by BP before a retest may be considered. 6.2

Single qualification

6.2.1

General

Add Qualification welds shall be assessed by VT and shall also be subject to RT. The agreed NDT regime shall reflect production NDT and shall examine the full weld circumference. Qualification of welders using GMAW (solid or cored wire) shall be by VT, RT, MUT, and mechanical testing to include face and root bends or side bends. In the case of manual welds, nick break tests are also required. If the application of AUT for the inspection of production girth welds has been agreed by BP, it may be used for assessment of the welder qualification welds in place of RT. However, the acceptance criterion used shall be Section 9 rather than an ECA based criterion. The position of the pipe used in the test shall determine the extent of qualification as follows:

6.2.2

a.

Horizontal pipes shall be used to qualify for welds between pipes positioned within 25° of the horizontal.

b.

Vertical pipes shall be used to qualify for welds between pipes positioned within 25° of the vertical.

c.

Pipes at 45° to the horizontal shall be used to qualify for welds between pipes positioned at intermediate angles between 25° and 65° to the horizontal.

Scope

Modify c. to Read For SMAW, a change of electrode manufacturer and brand name 6.3

Multiple qualification Modify to Read Multiple qualification of the welder shall not be permitted.

6.4

Visual examination Modify Paragraph 2 to Read Filler wire protruding into the pipe bore shall not be permitted.

6.6

Radiography—butt welds only

6.6.1

General

Modify to Read RT (or AUT: see 6.2.1 above) shall be performed on the qualification welds using the same RT (AUT) procedure as to be used in production. Testing procedures and acceptance criteria shall be subject to approval by BP.

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7

Design and preparation of a joint for production welding

7.1

General Add Any protective coating on the end bevel shall be removed before welding by a BP approved method. Before welding, the pipe end shall be cleaned inside and out using power driven wire brushes, grinders or other method approved by BP, for a minimum distance of 40 mm (1½ in) from the edge of the weld bevel. If AUT is to be used, a reference line at a specified distance from the root face shall be scribed onto the pipe surface to allow the AUT equipment to identify the exact location of the root bead. Arc burns outside of the weld groove shall not be permitted. Remedial action on arc burns shall be in accordance with 10.6. Attachment of welding return cables by welding shall not be permitted. Arc burns caused by a faulty attachment shall be removed in accordance with 10.6. Repair of the pipe body by welding shall not be permitted.

Add 7.1.1

Weld proximity

The distance between pipeline girth welds shall not be less than twice the outside diameter of the pipe. The distance between pipeline girth and branch/attachment welds shall not be less than one pipe diameter. The distance between branch/attachment welds on the pipeline shall not be less than one pipe diameter. 7.2

Alignment Modify to Read Pipe ends shall be aligned by rotating pipes, avoiding pipe end bevel damage, thereby achieving accurate fit up for welding. The misalignment between the internal surfaces shall not exceed the lesser of 3.0 mm (1/8 in.) or 1% of the pipe internal diameter at any point. The longitudinal (or spiral) weld ends shall be separated, at the circumferential weld, by 90º or a circumferential distance of 250 mm (10 in), whichever is the smaller. Longitudinal welds shall lie within the top half of the pipe circumference. If abutting pipes have the same outside diameter with different nominal bores, the smaller bore shall be machined, ground or filed, to produce an internal taper no steeper than 1 in 4; alternatively, a transition piece may be inserted. Internal tapering shall be subject to BP approval if the taper will interfere with ultrasonic inspection. Internal tapering may not be used with AUT. Any misalignment in pipe to fitting girth weld set-ups, which exceeds 3.0 mm (1/8 in.) at any point on the internal surface, shall be subject to corrective action agreed with BP. Slight misalignment may be corrected using a bronze-headed or other soft-faced hammer of mass not exceeding 5 kg (11 lb). Hammering must not impinge on the weld area. Heat shall not be used to correct excessive misalignment.

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For some pipeline applications, e.g. pipelines subject to high strain, strain based design pipelines, or pipelines carrying corrosive fluid streams, a more stringent maximum limit for internal offset may need to be specified. In such instances, it is necessary to take this into account when ordering the line pipe as more stringent tolerances on diameter, wall thickness, and out-of-roundness need to be specified. In the case of seamless pipes, the ends may require match boring. 7.3

Use of line-up clamp for butt welds Modify to Read

7.3.1

General

Internal alignment clamps shall be used for pipe-to-pipe butt welds and shall not be released until 100% of the root pass is completed. If access does not permit the use of an internal clamp for pipe-to-pipe welds, e.g. on tie-in welds, an external clamp shall be used. For short pipelines and small diameters (< 150 mm (6 in)), the use of an external clamp may be proposed for BP approval. A welding sequence that distributes the stress as evenly as possible shall be used, e.g. two welders working diametrically opposite each other. At least 50% of the root pass shall be completed before the external clamp is released. 7.3.2

Tacking (tack-welding)

Tack welds (if used) shall be deposited by qualified welders using low hydrogen welding in accordance with an approved welding specification. If preheat is specified, it shall be applied before tack welding and be effective over a distance equal to three times the wall thickness or 75 mm (3 in) whichever is the greater and shall be maintained until the joint is complete. Alignment by tacking for fabrication welds, e.g. for pipe to flange joints, shall be subject to the approval of BP. The following shall apply when tacking is used: a.

The joints to be tacked shall be adequately supported.

b.

The tack welding shall be undertaken by welders qualified in accordance with Section 6.

c.

The preheat level required for the main WPS shall be applied for tacking and shall not be less than 50°C (122°F.

d.

The preferred method is bullet tacking. The bullets shall be made from compatible linepipe material and shall be removed as the welding progresses. A bullet tack is made by welding a small piece of material into the weld bevel. If root tack welds are to be incorporated into the final weld, they shall be at least 25 mm (1 in) long and shall be thoroughly cleaned of slag and taper ground at each end to ensure complete root continuity.

e.

A minimum of four tacks shall be used for diameters greater than 100 mm (4 in). More tacks may be required for diameters greater than 300 mm (12 in).

f.

Welding shall be confined to the weld preparation.

g.

Tacks shall be removed by grinding as root welding progresses around the butt.

h.

Tacking shall be incorporated in the WPQT if it is to be used in production.

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7.4

Bevel

7.4.1

Mill bevel

Modify to Read If pipes are supplied with mill bevelled ends, the API 5L standard bevel will normally be provided. Alternative bevels may be supplied in order to conform to the joint design specified in the WPS. 7.4.2

Field bevel

Modify to Read Weld bevels shall be prepared by machining with a floating head cutter. The bevelling machine shall follow the ID surface contour in order to ensure a consistent root face dimension. Mechanised thermal cutting may be accepted for tie-in welds. The cut surface shall be ground back nominally 2 mm (1/16 in). Manual cutting of field bevels is not permitted. Add 7.4.3

Bevel condition

Surfaces to be welded shall be free of primers, paints, or coatings. Anti-spatter compounds shall not be applied to surfaces to be welded. Fusion faces and adjacent material shall be free from fins, planar defects or cracks, tears, moisture, scale, rust, grease, or any other foreign matter immediately before welding. Surfaces contaminated with oil or grease shall be cleaned utilizing a BP approved solvent. Degreasing of base metal shall extend at least 50 mm (2 in) from the edge of the fusion faces on both ID and OD surfaces. Solvents used for cleaning shall be used from a suitable container and approved by BP as HSE compliant with necessary documentation available. 7.4.4

Inspection and treatment of bevels

On pipe which is to be cut back, a zone extending 100 mm (4 in) from the proposed position of the new field bevel shall be examined by VT and UT to the requirements of the appropriate pipe material specification. BP may permit minor imperfections in the pipe ends to be repaired by grinding, before assembly for welding, provided the remaining wall thickness is acceptable as confirmed by UT. Weld repairs to pipe ends shall not be permitted. 7.5

Weather conditions Add If necessary, measures shall be taken, e.g. by covering the pipe ends, to prevent water or other extraneous matter being channelled into the weld region.

7.6

Clearance Add Full and adequate clearance to the joint shall be provided for the welders so that the full circumference is readily accessible without hindrance to the welding operation. This may require staging, pipe lifting, or further excavation.

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7.7


Cleaning between beads Add Stops and starts should, if necessary, be ground and visible defects and high points shall be removed by grinding before a further weld run is deposited. Contact tips shall not be fused into the weld metal. A visual inspection shall be undertaken between weld passes to confirm no copper has been deposited. The use of manual slag hammers, chisels, and lightweight vibrating tools for the removal of slag and spatter is permitted and is not considered peening, except that excessive mechanical working of the surface that may mask surface defects or otherwise inhibit a proper visual inspection is prohibited.

7.10

Identification of welds Add Accurate records to identify the work of each welder shall be maintained and a weld identification system providing each weld with a unique identification number shall be submitted. Each weld shall be identified with the weld identification number on the adjacent steel surface using an indelible paint or ink marking system. The work of each welder shall be identified at each weld or portion of weld with his unique identification symbol using an indelible paint or ink marking system.

7.11

Pre-and post-heat treatment

Add 7.11.1

Preheat and interpass temperature

Preheat and interpass temperatures shall be in accordance with the BP approved WPS; see 5.3.2.13. Preheating shall be applied by gas or electrical equipment. Induction heating is preferred for main pipeline welding and is mandatory for main line welding of pipe diameters greater than 500 mm (20 in). Hand held gas torches shall not be used for main pipeline welding if preheats greater than 80°C (176°F) are required. Welding or cutting torches shall not be used for preheating purposes. The preheating equipment shall maintain a satisfactory temperature distribution and shall not interfere with the welding operation. Damage to any coatings shall be avoided. Preheating shall be applied uniformly on both sides of the joint preparation around the entire periphery. Local preheating may be used for repair welding. Correct preheat temperatures shall be maintained throughout the welding of the joint. The preheat temperature shall be measured at a minimum distance of 75 mm (3 in) from each edge of the weld bevel at four circumferential locations, each approximately 90° apart. Preheat temperature measurement shall be made on the heated face of the pipe after a time interval following the removal of the heat source to allow for temperature equalisation. The time interval shall be 1 minute per 12.7 mm (½ in) of wall thickness, e.g. 2 minutes for 25 mm (1 in) thick material. The preheat temperature should be confirmed immediately before the commencement of welding and around the whole joint whilst welding is taking place. The preheat temperature shall not exceed the minimum preheat temperature given in the approved WPS by more than 50ºC (90ºF). Interpass temperature shall be measured on the parent material at the edge of the weld bevel near the weld start location. The temperature shall be measured immediately before the passage

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of the arc. The maximum specified interpass temperature shall not be exceeded. Interpass temperature checks shall be made during welding. For continuous 1G rotated or 5G welding, interpass temperature shall be measured once per complete revolution around the weld circumference. Temperature indicating crayons which melt on attaining the specific temperature may be used to check preheat and interpass temperature, but shall not be marked on weld bevels, weld beads, or surfaces to be welded. Temperature indicating crayons or paints, which indicate temperature by colour change, shall not be used. Alternatively, suitably attached (and calibrated) thermocouples or calibrated contact or optical pyrometers may be used to check preheat and interpass temperatures. If pipe-to-pipe joints are to be left partly completed, the joint shall be wrapped in dry insulating, heat-resisting material with a waterproof backing and shall be cooled at a slow uniform rate. Preheat shall be re-applied and the specified temperature attained before recommencement of welding. 7.11.2

Post heat (including post weld heat treatment)

If post heating or post weld heat treatment is specified, the pipe shall be heated for a minimum distance on both sides of the joint equal to 2.5(Rt)½ (where R is the external radius and t is the wall thickness of the pipe). The temperature at the edge of this heated band shall be not less than half the peak temperature. The method and technique of post weld heat treatment shall be subject to the approval of BP. Thermocouples shall be used for recording post weld heat treatment temperatures and shall be positioned to give a true measure of the joint temperature. As a minimum, thermocouples shall be positioned at the 6 and 12 o’clock positions. For pipe sizes above 600 mm (24 in), thermocouples shall also be placed at the 3 and 9 o’clock positions. The thermocouples shall be in metallic contact with the material being heat treated and shall be securely attached. Thermocouple wires and junctions shall be protected from direct heat. If electrical resistance heating is used, thermocouples shall have a protective wrapping to prevent direct radiation on to the hot junction. After use, thermocouples shall be removed and any remaining attachment material shall be removed by grinding. The ground surface shall be examined with MT. Add 7.12

Weld interruption Normally, welds shall be completed by continuous welding. Offshore pipeline welds or welds on fittings, tie-in welds, or repairs shall not be allowed to cool below the specified minimum preheat temperature before weld completion. No welds shall be allowed to cool below preheat temperature before the completion of four full circumferential passes. For pipe-to-pipe welds for onshore pipelines being constructed on steep gradients (> 10%), the welds shall not be left partially completed for longer than four hours.

7.13

Branches

7.13.1

General

Procedures for cutting, joint preparation, setting up, welding and NDT shall be subject to approval by BP. Forged fittings shall be used for branch and other pressure containing attachments, unless otherwise approved by BP.

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Branch welds shall be sited away from other welds on the pipeline (see 7.1.1). The pipe area surrounding a branch weld shall be tested for laminations using UT up to a distance of 100 mm (4 in) surrounding the projected locations of the weld toes. Any laminations found (individual or cluster) shall not exceed a total area of 500 mm2 (3/4 in2). No lamination, regardless of size, shall be permitted within 25 mm (1 in) of the projected weld toes. 7.13.2

Set-in type fittings

Set-in type fittings shall be attached to the pipe using a low hydrogen welding process. If accessible, and following completion of the full weld, the root bead shall be ground flush on the inside of the pipe, its location clearly marked with indelible pen, and inspected with VT and MT. Weld caps shall be subjected to VT and MT. The full welds shall be examined with RT using the SWE/SWV technique with the film inside and the radiation source outside, using a minimum source to film distance of 600 mm (24 in). A minimum of four equidistantly spaced separate exposures shall be used for branches ≤ 150 mm (6 in) nominal bore; a minimum of six equidistantly spaced separate exposures shall be used for branches > 150 mm (6 in) nominal bore. The DWE/SWV technique may only be used if approved by BP. In any event, the centre of the radiation beam shall pass through each weld region being tested at normal incidence to the weld face. 7.13.3

Set-on type fittings

Set-on type fittings shall be attached to the pipe using a low hydrogen welding process. The root bead and weld cap shall be examined by VT. VT of the root bead shall be undertaken through the bore of the fitting from the outside of the pipe. The weld cap shall also be examined with MT. If access allows, UT shall be undertaken from the inside surface of the fitting. 7.14

Fillet weld attachments Procedures for welding and NDT shall be subject to approval by BP. The pipe area surrounding a fillet weld shall be tested for laminations using UT up to a distance of 100 mm (4 in) surrounding the projected locations of the weld toes. Any laminations found (individual or cluster) shall not exceed a total area of 500 mm2 (3/4 in2). No lamination, regardless of size, shall be permitted within 25 mm (1 in) of the projected weld toes. If any fillet welds are to be made using multiple passes, the first pass shall be deposited mainly on the pipe and the final weld pass shall not touch the pipe. Completed fillet welds shall be examined by VT and MT.

8

Inspection and testing of production welds

8.1

Rights of inspection Add The right of inspection includes NDT undertaken by BP personnel in addition to any NDT undertaken by the contractor. For instance, BP may choose to inspect welds by MUT.

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8.2


Methods of inspection

Add 8.2.1

NDT general

Each joint shall be thoroughly cleaned using power driven wire brushes and hand tools following welding and before inspection. Spatter and extraneous material shall be removed. Proposed NDT procedures shall be submitted in writing to BP for approval. Qualification of NDT procedures shall be made on the welding procedure qualification weld(s) or welds made in accordance with the approved WPS, unless otherwise agreed by BP. 8.2.2

NDT method

The full circumference of pipeline butt welds shall be examined by RT or AUT. For wall thickness above 25 mm (1 in), AUT is the preferred NDT technique. The use of automatic ultrasonic testing (AUT) shall be subject to approval by BP on a case by case basis. If the use of AUT has been approved, testing shall be performed in accordance with BP GP 43-34. The use of AUT shall not be permitted in place of radiography for the following weld types: a.

Welds connecting pipes with an internal taper

b.

Butt welds to valves, flanges and other fittings

c.

Welds in land pipelines to be submerged or buried in river, rail or road crossings. These welds shall also be subject to MUT or AUT in addition to radiography.

If RT is being used to examine welds produced by GMAW or cored wire systems, MUT shall be used to supplement RT. The extent of supplementary UT testing will be specified by BP. MUT and MT equipment and personnel shall be available at site for the full duration of pipeline construction. 8.2.3

Timing of NDT

Production welds shall be examined by VT immediately upon completion of welding. On a pipelay vessel, the weld shall not be moved past the weld repair station until the weld NDT interpretation has been completed. Coating or wrapping of a welded joint shall not begin until the weld NDT interpretation has been completed. 8.3

Qualification of inspection personnel Add Inspectors shall be qualified in accordance with 1.8.2.

8.4

Certification of nondestructive testing personnel Add NDT personnel shall be certificated in accordance with 1.8.3.

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9

Acceptance standards for non-destructive testing

9.1

General Modify to Read The acceptance standards defined in Section 9 shall be the minimum requirements for BP pipelines in which RT is the primary NDT method. If the use of AUT has been approved by BP, the requirements of Section 9 shall be augmented by an ECA to determine flaw dimensions and acceptance levels, which shall be subject to BP approval (see Appendix A). If unacceptable flaws occur in more than five consecutive welds, or if in the opinion of BP a particular flaw type becomes repetitive in terms of its size and/or location, the cause of the flaws will be investigated by the BP welding engineer. If necessary, welding shall be terminated until the cause of unacceptable flaws has been established and satisfactorily resolved. For off-line fabrication, e.g. risers or welding of nipples to valve bodies, the pipeline designer may wish to specify acceptance criteria that do not permit defects such as lack of fusion or lack of penetration, e.g. ASME B31.3 [2] Table 341.3.2 severe cyclic conditions. More onerous acceptance criteria than those in Section 9 may be required for surface breaking root flaws for some pipeline duties. These acceptance criteria are specified on a project by project basis.

Add 9.1.2

Visual acceptance – weld profile

Completed welds shall have a uniform appearance without excessive changes in profile and shall blend smoothly into the parent material. At no point shall penetration of the root bead into the bore exceed 3 mm (1/8 in). For pipe diameters less than 60 mm (2 3/8 in), this penetration shall not exceed 1.5 mm (1/16 in). 9.3

Radiographic testing

9.3.2

Inadequate penetration due to high-low

Modify Paragraph a. to Read The length of an individual indication of inadequate penetration due to high-low (IPD) exceeds 25 mm (1 in). 9.3.6

Internal concavity

Modify Second Sentence to Read Internal concavity (IC) up to 25% of the total length of weld is acceptable provided the density of the radiographic image of the IC does not exceed that of the thinnest adjacent base metal. 9.3.7

Burn-through

Delete 9.3.7.2 Modify First Paragraph of 9.3.7.3 to Read For all pipe diameters, a burn-through (BT) shall be considered a defect if any of the following conditions exists:

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9.3.9


Porosity

Add The total area, when projected radially through the weld, shall not exceed 2% of the projected weld area in the radiograph. The area shall be the length of the weld affected by the porosity (with a minimum length of 150 mm (6 in)) times the maximum width of the weld. 9.3.10

Cracks

Modify to Read Any form of crack or suspected crack shall be unacceptable. 9.3.11

Undercutting

Add The aggregate length of internal undercut (IU) exceeds 25 mm (1 in) in any continuous 300 mm (12 in) of weld length. 9.3.12

Accumulation of imperfections

Add c.

The total aggregate length of all indications, including incomplete penetration due to highlow and undercutting, exceeds 15% of the weld length.

Add 9.3.14

Tungsten inclusions

Tungsten inclusions shall not exceed two per weld and shall be separated by a minimum distance of 50 mm (2 in). 9.3.15

Copper inclusions

Not permitted 9.7

Visual acceptance standards for undercutting

9.7.2

Acceptance standards

Modify to Read Weld cap undercutting exceeding 0.4 mm (0.016 in) depth shall be unacceptable and shall be blended out by light grinding or filing before performing NDT. If blending reduces the pipe wall thickness below the specified minimum, the entire circumferential weld shall be cut out and the pipe ends re-bevelled and re-welded. Add 9.8

Suspect welds Any weld suspected of not having been produced in accordance with the approved welding procedure shall be cut out, and may be subject to investigation at the discretion of BP.

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10

Repair and removal of defects

10.1

Authorisation for repair Add A full record of repairs shall be maintained. Records shall be made as each flaw is discovered, and shall include the following: a.

The weld number

b.

The type and size of flaw

c.

The circumferential location (defined to an approved system)

d.

An estimate of the flaw depth (assessed by ultrasonic test, if possible)

e.

Name of the welder who produced the flaw

f.

Repair welding procedure number

g.

Name of repair welder

h.

Copy of inspection report for the repair

i.

Date of repair

Defects shall not be repaired in any part of the weld without prior approval by BP. Repairs shall be witnessed by BP; and, the relevant NDT records shall be made available to BP at that time. 10.1.1

Cracks

Modify to Read Welds with cracks (other than small crater cracks < 4 mm (5/32 in) in length) shall be removed from the pipeline. The welding procedure shall be suspended until the cause is identified and remedial measures implemented to prevent further occurrence. Production welding with the suspended WPS shall only recommence following approval from the BP Welding Engineer. Small crater cracks shall be removed by local grinding and repaired. 10.1.2

Defects other than cracks

Modify to Read Weld repairs shall be made in accordance with a BP approved repair welding procedure. Weld repair lengths shall be limited to 30% of the weld length for repairs that do not open the root. If a repair opens the root, a maximum of 20% of the weld length shall be repaired. If the repair cannot be implemented within these limitations, the weld shall be cut out. Further restrictions on weld excavation may be required if the weld is under load at the time of the repair, e.g. beyond the tensioners of a laybarge. In such cases, verified calculations justifying the excavation size shall be submitted for BP approval. If a root repair weld in a pipeline fails to comply with the requirements of Section 9, the entire circumferential weld shall be cut out and the pipe ends re-bevelled and re-welded. If necessary, a second repair may be attempted for regions apart from the root. If this second repair fails to meet the requirements of Section 9, the entire circumferential weld shall be cut out. For grades above X70, only a single repair attempt shall be permitted. For repair of arc burns see 10.6. Internal weld repairs shall not be permitted except for pipe-to-fitting welds in which the repair can be undertaken from the open end of the pipe or fitting. No more than two separate repairs are allowed in any single weld.

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10.2


Repair procedure Add Repair weld procedure qualification is required. At the discretion of the BP Welding Engineer, repair welding using the original WPS may be permitted if the material grade is < X52 and the welding process(es) is manual or semi-automatic and the weld preparation is similar to the original weld preparation. The repair weld procedures shall be qualified in accordance with Section 5. However, it is not necessary to make a full circumferential repair weld. It is only required to make sufficient repair weld to provide material for mechanical testing. The radial position of the test repair weld shall be approved by BP. Single pass repairs are only permitted for cap defects. Each repair type to be used in production shall be separately qualified, e.g.: -

full penetration repair

-

partial penetration repair

-

partial penetration re-repair

-

cap repair

-

internal repair (if permitted)

-

intermediate repairs (repairs made with a different process during the course of making the girth weld, e.g. SMAW repairs to an automatic root)

The repair weld procedure qualification shall be inspected by VT, MT, MUT and RT. Mechanical testing shall be undertaken in accordance with 5.6 although the number of mechanical tests may be reduced as shown in Table G. Individual repair weld procedure qualification excavations shall be limited to a length of 300 mm (12 in). 10.2.2

Add The portion of weld cut out for repair shall be tapered at the sides and ends to give adequate access for rewelding. Metal may be removed by thermal gouging followed by grinding. Grinding shall be used for the last 3 mm (1/8 in) through to the root. Air-arc gouging shall be controlled by a procedure documenting the allowed variables as required by AWS C5.3. The minimum allowable repair length shall be 50 mm (2 in) at the bottom of the groove.

10.2.3

Add Excavations associated with the partial thickness repair of planar flaws shall be tested by MT to confirm complete removal of the flaw.

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Table G - Type and number of test specimens for repair weld procedure qualification test

Type of Repair

Single Pass

Tensile Strength (Cross Weld Tensile) a

0

All-Weld Metal Tensileb

Bend f

Charpy Impact Tests c (set of 3)

Macro/ HV10

CTOD (set of 3)b

0

0

0

1

0

d

1

2

e

1

2

Multi Pass – Partial

2

1

2

5

Multi Pass – Full Penetration

2

1

2

3

NOTES: a If the strength of the weld may be significantly affected (e.g. low strength repair electrode on thin wall pipe) then transverse tensile testing shall be undertaken. b CTOD and Weld Tensile testing shall be undertaken if the acceptance criterion is based on an ECA. One set of CTOD specimens shall be notched in the weld metal and one in the HAZ. c One set of Charpy impacts specimens shall be located in the repair weld metal and associated parent material HAZ at the fusion line and fusion line +2 mm. d For partial penetration repair welds, a further two sets of Charpy specimens shall be notched to sample the repair weld metal and associated original weld metal HAZ at the fusion line and fusion line +2 mm. e For welds greater than 20 mm, additional sets of weld metal and fusion line Charpys shall be located at the outer surface for full penetration repair welds. f The bend specimen type shall be selected in line with 5.6 based upon the thickness and diameter of the weld.

Add 10.6

Arc burns BP shall have the option to require removal of weldments with more than one arc burn from the pipeline. Repair of arc burns shall be by careful grinding or filing until visible signs of the arc burn are removed. Welding shall not be used to repair arc burns. The dressed area shall blend smoothly into surrounding base metal and shall be examined by VT and MT to ensure freedom from defects. The remaining wall thickness shall be checked with UT. If blending to remove the effects of arc burns reduces the wall thickness below the specified minimum, the defective pipe section shall be cut out and the pipe re-bevelled and re-welded. If a nipple is used to replace the defective section, its length shall meet the requirements of 7.2.

11

Procedures for nondestructive testing

11.1

Radiographic test methods

11.1.1

General

Add Radiographic testing shall be conducted using X-ray equipment. If the use of X-ray equipment is impracticable, Iridium 192, Ytterbium 169 or Selenium 75 may be used subject to approval by BP; other sources of gamma rays are not permitted. Radiographic practice shall be in accordance with this GIS and ISO 17636. Radiographic procedures shall be qualified and approved by BP before use. As part of the radiographic procedure qualification, test radiographs shall be produced using each radiographic procedure. These shall be made on the welding procedure qualification welds

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or welds made with the production WPS. The full circumference of each test weld shall be radiographed. For radiographic procedure qualification, wire type IQIs, meeting the requirements of ISO 2504, ASTM E747 or BP approved equivalent, shall be placed across the weld on both the source side and the film side of the area being examined. The sensitivity level, obtained using the film side IQI, shall be no worse than that given in Table H. The corresponding sensitivity for the source side IQI shall be recorded. If any test radiograph shows more than one visible wire of the film side IQI, compared to the source side IQI image, BP has the option to reject the radiographic procedure. The procedure test radiographs shall be submitted to BP for approval before the start of production. New procedure test radiographs may be requested, at the discretion of BP, whenever any change is made in operating technique, or whenever production radiographs differ appreciably from the detail, contrast, definition or density of the qualifying radiographs. Procedure test radiographs shall be readily available for comparison purposes in each darkroom used for radiographic viewing. Film type shall be ISO 11699-1 Class T2 or ASTM E1815 Class I, e.g. Agfa Structurix D5 or Kodak Industrex T200, or finer grain (slower) film. If it is shown that exposure times would exceed 2 minutes using X-ray equipment with this film, the use of ISO 11699-1 Class T3 or ASTM E1815 Class II may be permitted at the discretion of BP. Lead (Pb) intensifying screens shall be used. BP may approve the use of fluorometallic screens as an alternative, if it can be demonstrated that test procedures and results are of a standard acceptable to BP. 11.1.2

Details of procedure

11.1.2.2

Film radiography

Add to a. Brand name, including specific model name/ number, of X-ray equipment. Modify e. to Read Exposure conditions: For X-ray: Exposure time, mA and kV. For gamma: Curie-minutes and Gigabecquerel-minutes. Add to f. Type and brand name of each processing chemical. 11.1.3

Exposure geometry

11.1.3.1

Film radiography

Modify to Read Source-weld-film arrangements shall comply with ISO 17636 except that the elliptical technique shall be used on girth welds on pipe ≤ 88.9 mm (3.5 in.) diameter. The perpendicular technique (straight through) exposures shall not be used unless approved by BP. The single wall exposure for single wall viewing (SWE/SWV) technique with the radiation source located inside the pipe/ fitting shall be the preferred technique for RT of girth welds. 11.1.4

Type of image quality indicators (IQI)

Add Wiretype IQIs corresponding to ISO 2504, ASTM E747, or approved equivalent, shall be used.

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11.1.5


Selection of image quality indicators IQI

Add IQIs sensitivity requirements shall be as given in Table H. Table H - IQI sensitivity levels a

Thickness

X-Radiography

Gamma Radiography

(in)

(mm)

SWE/SWV

DWE/SWV

DWE/DWV

SWE/SWV

DWE/SWV

DWE/DWV

0.18 – 0.24

4.5 – 6.0

2.0%

2.5%

3.2%

2.6%

2.7%

3.5%

>0.24 – 0.35

>6.0 – 9.0

1.7%

2.0%

3.0%

2.4%

2.5%

3.2%

>0.35 – 0.55

>9.0 – 14.0

1.5%

1.8%

Note b

2.4%

2.5%

Note b

>0.55 – 0.73

>14.0 – 18.5

1.4%

1.7%

NA

2.0%

2.2%

NA

>0.73 – 1.02

>18.5 – 26.0

1.3%

1.7%

NA

1.7%

2.0%

NA

>1.02 – 1.6

>26.0 – 40.0

1.1%

1.7%

NA

1.5%

1.8%

NA

> 1.6

> 40.0

Note b

Note b

Note b

Note b

Note b

Note b

a Thickness for SWE/SWV and DWE/SWV is estimated single weld thickness. Thickness for DWE/DWV is one wall thickness plus one estimated weld thickness. b Sensitivity requirement to be agreed with BP following production of test radiographs. Sensitivity shall be no worse than the values given in this Table. Sensitivity values are based on IQI placed on film side for SWE/SWV and DWE/SWV exposures and IQI on source side for DWE/DWV exposures. Sensitivity shall be calculated using the formula: Sensitivity =

11.1.8

Thickness of thinnest wire visible in weld area Thickness a Identification of images

Add The Radiograph shall contain the following information: a.

Project name, project number and pipeline identification

b.

Weld number

c.

Whether the radiograph is of a repair weld, of a replacement weld or a re-shoot of radiograph

d.

Marker(s) indicating the position of the radiograph in relation to the weld

e.

Pipe diameter and thickness

f.

Material grade

g.

Date

h.

WPS

11.1.9

Storage of film and other imaging media

11.1.9.1

Film

Add Radiographs shall be stored in an environment that will not detrimentally affect the radiographs. Boxes shall be used to store radiographs in multiples of 25, 50, or 100 welds. The weld numbers that apply to the stored radiographs that each box contains shall be clearly visible on each box.

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11.1.10

Film density

11.1.10.1

Film density

Modify to Read Except for small localized areas caused by weld weave or discontinuities, the radiographic density shall be between 2.0 and 3.2 in the weld area. If this density range cannot be achieved within the full weld width in a single exposure, then the above density range shall be achieved by producing two radiographs of the weld area at different exposures or by using the sandwich technique, unless otherwise agreed by BP. Densitometers shall be used for measuring density and shall be calibrated using a density strip (density reference scale) of known densities. A density strip certified within the last 3 years to a recognized standard, e.g. NIST or BAM, shall be present on site. To save wear and tear on the calibrated density strip, a working density strip may be used for checking and calibrating densitometers; this must be checked against the certified density strip at no more than 3 monthly intervals. 11.1.10.2

Film viewing equipment

Add The brightness of the illuminated radiograph shall be such that it can be interpreted satisfactorily. Illuminators shall meet the requirements of ISO 5580. 11.1.11

Image processing

Add Radiographic film shall be dried thoroughly before viewing. Films shall be processed to allow storage without deterioration for a minimum period of five years. One radiograph in every 100 shall be subjected to a residual thiosulphate test. 11.2

Magnetic particle test method Add Magnetic particle testing shall comply with ISO 17638 or ASTM E709. The non-fluorescent wet method of MT using white contrast paint and an AC yoke (110V) shall be used. Dry powder MT may be used for repair groove inspection. The AC yoke shall be capable of lifting 4.5 kg at 150 mm (10 lb at 6 in) pole spacing. Poles shall make maximum contact with the test surface during inspection. MT procedures, including the method for determining adequate flux levels in the test area, shall be qualified. MT procedures shall be approved by BP before use.

11.4

Ultrasonic test methods

11.4.1

General

Add Manual ultrasonic testing shall comply with ISO 17640 or ASTM E164. UT procedures shall be approved by BP before use. If the use of AUT is proposed, qualification of the AUT procedures and production testing shall comply with the requirements of BP document GP 43-34.

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12


Mechanised welding with filler metal additions Add If mechanised or automatic processes for main line welding, tie-in welding or for multiple jointing of pipeline sub-assemblies are proposed, the bid proposal shall include full details of the processes to be used, the associated welding equipment, and the proposed area of application. For mainline welding applications, the proposal shall list the number of welding stations (root pass to final capping pass) on a spread by spread basis and detail the equipment and number of welders and other personnel required to operate each station. Full details of the welding shelters shall also be provided. A similar level of detail shall be provided for tie in welding and multiple jointing. Mechanised (automatic) 2G or 5G welding equipment should be operated in-conjunction with data logging facilities capable of recording the essential variables associated with the arc including wire feed speeds and travel speeds. The equipment shall record all parameters for each pass of every weld at a minimum rate of once per 10 degrees of angular rotation and shall indicate the angular position of each measurement. This data shall be readily retrievable for monitoring purposes and shall form part of the pipeline construction data package. Data logging is mandatory if welding with either multi torch or multi wire systems and for girth welds made in ≥ X80 grade linepipe. Each mechanised (automatic) welding station shall be demonstrated to be fully operational before it is employed to weld any joints that will be incorporated into the pipeline. For example, for a spread of welding stations this demonstration may consist of two full girth welds made consecutively, each weld being required to meet the production acceptance criteria without the need for any repair. NDT shall utilise the agreed pipeline NDT techniques and equipment. Internal welding equipment shall also require operational demonstration. Each of these preconstruction welds shall be uniquely identified and reserved for possible mechanical evaluation by BP. This operational demonstration shall be repeated as agreed with BP, but should as a minimum be repeated after interruptions ≥ 7 days in pipeline welding and when a welding spread is disassembled and transferred from one section of the line to another. The proposal shall also detail the intended level of technician support for equipment maintenance and list the principal spares that will be available in order to maintain equipment serviceability for the duration of the pipelay. The proposal shall also advise if a manual welding procedure is to be qualified for production or repair welding.

12.2

Procedure qualification Modify to Read The requirements for the qualification and testing of procedures for mechanised (automatic) welding shall be as per Section 5.

12.3

Record Add Additional requirements for mechanised (automatic) welding have been incorporated in Section 5.

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12.4


Procedure specification Modify to Read The requirements for the procedure specification of mechanised (automatic) welding have been incorporated in 5.3.

12.5

Essential variables Modify to Read The requirements for mechanised (automatic) welding have been incorporated in 5.4.

12.6

Qualification of welding equipment and operators Modify to Read The requirements for mechanised (automatic) welding have been incorporated in Section 6.

13

Automatic welding without filler-metal additions Delete

Appendix A—Alternative acceptance standards for girth welds Add The use of alternative acceptance standards for girth welds shall be subject to BP approval before contract award. The ECA method and testing shall be proposed for BP approval before the commencement of WPQT. The ECA method may be that described in API 1104 or other recognised codes (i.e. BS 7910, EPRG Guidelines or CSA Z662). If API 1104 is used then consideration against plastic collapse shall also form part of the ECA. The output of the ECA shall be used to develop the weld NDT acceptance standard. The weld acceptance standard shall include an appropriate NDT sizing allowance (see GP 43-34) which shall be clearly documented. In addition to the limits derived from the ECA, the following restrictions on defect size shall apply: •

Individual defects with a height greater than 4 mm (5/32 in) (before interaction assessment) shall not be permitted. Defects with a height greater than 4 mm (5/32 in) are unusual and their occurrence indicates abnormal welding. No acceptance of these defects is permitted even though the ECA may show safe defect heights in excess of 4 mm (5/32 in).

•

Irrespective of defect height, defects with a length greater than 7 times wall thickness (after interaction assessment) shall not be permitted.

Appendix B – In-service welding B.1

General Add Welding onto in-service “live” pipelines is usually an individual operation for each application and may only be undertaken under BP guidance. The in-service welding operation shall be subject to detailed planning and approval by BP in each instance. Although Appendix B gives useful guidance on this subject, the techniques employed for welding on to in-service pipelines and the fundamental technical issues to be addressed are different from those of new construction pipeline welding.

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Add

Appendix C – Additional requirements for pipelines subject to high strain levels C.1

Introduction This appendix applies to pipelines subject to plastic deformation during installation, e.g. installation by reeling. High strains may also be generated in operation and the effects on the welds should be assessed if operational strains are deemed to be significant. When evaluating the amount of strain at the weld expected during installation, the effects of misalignment, pipe strength variation, and coating stiffness shall be considered.

C.2

General

C.2.1

Linepipe

The requirements for materials to be used for high strain installation are more onerous than those for conventional pipe installation. The pipeline is required to have sufficient strain capacity to withstand multiple strain cycles, and uniform mechanical and dimensional properties are required to prevent excessive strain localisation. The BP GISs for linepipe give additional requirements for linepipe subject to high strain. Pipelines welded in accordance with this appendix shall use linepipe that complies with these additional GIS linepipe requirements. The linepipe GISs are GIS 43-311 GIS 43-312, GIS 43-313, and GIS 43-317. C.2.2

Welding process

Welding processes not previously used by the contractor with the proposed installation method shall require full scale qualification trials. The extent of the trials shall be determined by BP. Only low hydrogen processes shall be used. C.2.3

Welding consumables

The consumable selection shall be approved by BP and the consumable should have a track record with the selected installation method. The lot testing of weld consumables described in 4.2.2.4 shall be undertaken for each lot of welding consumables not tested in the welding procedure qualification. Additionally, -

the strain age testing in C.3 shall be performed.

-

the minimum Charpy energy shall be 70J at the impact test temperature.

-

the yield and UTS of the test weld shall exceed the maximum exhibited yield and tensile properties of the production pipe.

C.3

Weld procedure qualification testing

C.3.1

Simulation

The weld procedure qualification welds shall be subjected to full scale bending at the maximum strain predicted during installation. The number of cycles shall be determined from the number of cycles required for installation plus any contingency operations and agreed with BP. Weld repair procedures shall be included in the full scale trial and shall be located to undergo maximum strain. A procedure shall be provided for BP approval detailing the test string and test method. The following points shall be addressed: -

The type and number of welds. Each qualified WPS shall be included in the trial testpiece.

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-

The length of the test string and the spacing of the welds.

-

The bending frame dimensions and materials.

-

The calculated maximum strain (based on the carousel & pipe diameters).

-

A step-by-step description of the test.

-

The proposed strain rate.

-

Trial report proforma.

If a successful track record can be demonstrated using the same vessel to install pipe of similar properties with similar welding procedures then, at BP’s discretion, the full scale trial may be omitted. The spool base, the time between cycles, and the temperature shall be considered when evaluating existing data. C.3.2

Non-destructive testing

The weld procedure tests shall be subjected to the visual and non-destructive testing specified in Section 5 before and after straining. C.3.3

Mechanical testing

The strength of the welds shall be greater than the strength of the production pipes, however excessive overmatch should be avoided. C.3.3.1

Evaluation of weld procedures—bending trial welds

The welds shall undergo the mechanical testing specified in Section 5. However, the transverse tensile locations shall be rotated so that the test pieces are removed from the cardinal points. It is anticipated that this ensures that the areas undergoing maximum straining are tested. C.3.3.2

Evaluation of weld procedures—waived bend trial

If the full scale trial is waived, the weld procedures shall be subject to the full testing of Section 5 plus the following strain aged testing. Weld coupons shall undergo 5% tensile strain and ageing at 250°C (480°F) for one hour before the following tests are performed: -

1 all weld tensile specimen

-

2 transverse weld metal specimens

-

1 macrosection + hardness

-

2 sets of weld metal Charpy impact specimens

-

2 sets of fusion line Charpy impact specimens

-

1 set of fusion line + 2 mm Charpy impact specimens

-

Weld and HAZ CTODs

The testing shall be undertaken in accordance with Section 5 and the results shall meet the requirements of Section 5; however any large deterioration of properties compared with the unstrained specimens shall be cause for investigation. C.4

Production welding The maximum permitted pipe misalignment at the weld shall be 1.5 mm (1/16 in) unless larger misalignments are demonstrated to be tolerable and are agreed by BP.

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Appendix D—CTOD testing D.1

CTOD testing shall be undertaken in accordance with BS 7448 Parts 1 & 2 by a testing laboratory specifically approved for CTOD testing by BP.

D.2

Testing shall be based on the use of through thickness notched, single edge notched bend (SENB) specimens (BS 7448 Part 1 paragraph 5.1) in the NP orientation, unless agreed otherwise by BP.

D.3

Test specimens shall be notched and fatigue cracked to sample the microstructures at the weld centre line and in the coarse grained HAZ adjacent to the fusion line.

D.4

The number of valid test results employed to determine the characteristic CTOD of the weld metal and HAZ microstructures shall comply with BS 7910 paragraphs K.2.3 and 7.1.5.5. This may require a greater number of CTOD specimens than listed in Table 2.

D.5

The test temperature shall be MDT unless otherwise advised.

D.6

Post test metallography shall be used to identify the initiation point and the associated microstructure on a minimum of three HAZ specimens selected by BP. The initiation point of all brittle events shall be identified by metallography.

D.7

Any specific requirement for the achievement of a minimum CTOD will be specified on a project by project basis.

Appendix E—Pin brazing and aluminothermic welding of anode leads E.1

Joining technique Full details of the joining technique and associated equipment should be submitted to BP for approval prior to use.

E.2

Specification and approval of procedure

E.2.1

General

A procedure specification shall be submitted for BP approval. Before qualification, the parameters and information to be recorded and shown on the final WPS shall be proposed for BP approval. Relevant details of the test, including serial or catalogue numbers of the components and tools used, shall be recorded. For brazing, this shall include the electrical settings of the power supply. The procedure should be qualified by making three consecutive test joints, in the presence of BP, on material to be used in production. The test material should be selected by BP to represent the upper quartile of the carbon equivalent range. The electrical resistance of each weld should be measured and should not exceed 0.1Ω. The mechanical strength of the weld should be tested by means of a sharp blow from a 1 kg (2.2 lb) hammer. The test welds should be sectioned and prepared for metallographic examination. The following tests should be performed on the sections: E.2.2

Copper penetration measurement

The depth of copper penetration below the surface of the pipe material should be measured metallographically. The fusion line of the weld or braze should not be more than 1 mm below the pipe surface. Intergranular copper penetration of the pipe material shall not exceed 0.5 mm beyond the fusion line when a specimen is examined at a magnification not exceeding X50.

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E.2.3


Hardness survey

Each test section should be tested using an applied load of 10 kg. A traverse should be made across the weld zone. The traverse should consist of at least six impressions; two in the HAZ each side of the weld/braze and one in the parent metal each side of the weld/braze. The hardness values should not exceed 275 HV10 for sour service and pipe thickness less than 9.5 mm (3/8 in), 300 HV10 for sour service and pipe thickness above 9.5 mm (3/8 in) and 325 HV10 for non-sour service. Add

Bibliography American National Standards Institute (ANSI) [1]

AWS Z49.1 Safety in Welding, Cutting, and Allied Processes

American Society of Mechanical Engineers (ASME) [2]

ASME B31.3

Process Piping

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GIS 43-331 - API 1104 Pipeline Welding.pdf

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