MAJOR PROJECTS CONSTRUCTION SERVICES

Document Uncontrolled When Printed CPCS-SPEC-PLW-002 Revision 2 Page 1 of 39

MAJOR PROJECTS CONSTRUCTION SERVICES (PIPELINE)

SPECIFICATION FOR PIPELINE CONSTRUCTION (CANADA)

PIPELINE WELDING

CPCS-SPEC-PIPELINE-002 Name Position Department Signature Date

Prepared By

Luke Ludwig Senior Welding Specialist

MP Engineering & Construction Services - Pipeline

Bob Huntley Senior Construction Specialist


Reviewed By Robert Hogg Supervisor


Approved By Stan Cichacki Senior Manager

MP Engineering & Construction Services Canada- Pipeline

THE ORIGINAL SIGNED COPY OF THIS DOCUMENT IS RETAINED BY MP ENGINEERING AND

CONSTRUCTION SERVICES.


REVISION SUMMARY

Revision No. Effective Date Reason for and Description of the Change Replacement of Previous

Document

2 See manager approval date

Reviewed and updated to reflect current industry standards and Company’s best engineering construction practices

1

1 November 2011 Reviewed and updated to reflect current industry standards and Company’s best engineering construction practices

0

0 May 2010 New document N/A


TABLE OF CONTENTS

1 SCOPE........................................................................................................................................................ 5

1.1 GENERAL ................................................................................................................................................... 5

2 ACTS, REGULATIONS, LAWS, CODES AND STANDARDS .............................................................................. 5

2.1 GENERAL ................................................................................................................................................... 5

3 RELATED TECHNICAL SPECIFICATIONS AND STANDARDS ........................................................................... 5

3.1 GENERAL ................................................................................................................................................... 5

4 DEFINITIONS.............................................................................................................................................. 6

4.1 GENERAL ................................................................................................................................................... 6

5 WELDING REQUIREMENTS ........................................................................................................................ 7

5.1 GENERAL ................................................................................................................................................... 7

6 WELD CLASSIFICATION .............................................................................................................................. 8

6.1 TACK WELDS ..................................................................................................................................................... 8

6.2 GROOVE WELDS ............................................................................................................................................... 9

6.3 FILLET WELDS.................................................................................................................................................... 9

7 EQUIPMENT .............................................................................................................................................. 9

7.1 GENERAL ........................................................................................................................................................... 9

7.2 MECHANIZED WELDING ................................................................................................................................. 10

8 MATERIALS .............................................................................................................................................. 11

8.1 GENERAL ......................................................................................................................................................... 11

8.2 CONSUMABLES ............................................................................................................................................... 11

8.3 SHIELDING GASES ........................................................................................................................................... 12

8.4 PIPE AND COMPONENTS ................................................................................................................................ 12

9 QUALIFICATION OF WELDING PROCEDURE SPECIFICATIONS ................................................................... 12

9.1 GENERAL ......................................................................................................................................................... 12

9.2 ELECTRODE SELECTION ................................................................................................................................... 13

9.3 MAXIMUM TRAVEL SPEED .............................................................................................................................. 14

9.4 MINIMUM INTERPASS TEMPERATURES ......................................................................................................... 14

9.5 MAXIMUM TIME INTERVAL BETWEEN WELD PASSES .................................................................................... 14

9.6 MAINLINE WELDING PROCEDURE SPECIFICATION QUALIFICATION .............................................................. 15

9.7 MAINLINE WELD-REPAIR WELDING PROCEDURE SPECIFICATION QUALIFICATION ....................................... 15

9.8 TIE-IN WPS QUALIFICATION ........................................................................................................................... 16


9.9 FIELD FABRICATION WPS QUALIFICATION ..................................................................................................... 16

9.10 FIELD FABRICATION WELD-REPAIR WPS QUALIFICATION .............................................................................. 16

9.11 NON-DESTRUCTIVE TESTING OF WPS TEST COUPONS ................................................................................... 16

9.12 DESTRUCTIVE TESTING OF WPS QUALIFICATION TEST COUPONS ................................................................. 17

10 WELDER QUALIFICATION ......................................................................................................................... 18

10.1 GENERAL ......................................................................................................................................................... 18

10.2 TEST REQUIREMENTS ..................................................................................................................................... 19

11 PRODUCTION WELDING .......................................................................................................................... 21

11.1 GENERAL ......................................................................................................................................................... 21

11.2 WEATHER CONDITIONS .................................................................................................................................. 22

11.3 COLD WEATHER WELDING ............................................................................................................................. 22

11.4 CONTRACTOR DOCUMENTATION OF COMPLIANCE ...................................................................................... 22

11.5 WELDING PERFORMANCE REQUIREMENTS ................................................................................................... 23

11.6 PREPARATION OF PIPE.................................................................................................................................... 24

11.7 ALIGNMENT, FIT UP AND SUPPORT ................................................................................................................ 25

11.8 REMOVAL OF LINE-UP CLAMPS ...................................................................................................................... 26

11.9 PREHEATING ................................................................................................................................................... 27

11.10 WELDING SEQUENCE ...................................................................................................................................... 27

11.11 INTERNAL BACKWELDING ............................................................................................................................... 28

11.12 WELD COMPLETION ....................................................................................................................................... 28

11.13 NIGHT CAPPING .............................................................................................................................................. 29

11.14 ARC BURNS ..................................................................................................................................................... 29

11.15 PIPE PUPS ....................................................................................................................................................... 30

11.16 WELDING REFUSE ........................................................................................................................................... 30

11.17 WELD INSPECTION AND ACCEPTANCE ........................................................................................................... 31

12 WELD-REPAIRS ........................................................................................................................................ 33

12.1 GENERAL ......................................................................................................................................................... 33

12.2 WELD-REPAIR AND REMOVAL OF DEFECTS .................................................................................................... 34

12.3 INSPECTION OF WELD-REPAIRS ...................................................................................................................... 35

13 APPENDICES ............................................................................................................................................ 36


1 SCOPE

1.1 General

This Specification outlines the minimum requirements for pipeline mainline welding, weld-repair welding, tie-in welding and field fabrication welding of pipe and components for pipeline systems. This specification does not cover the requirements for shop fabrication welding, pipe mill welding, maintenance welding, or welding of final tie-ins to existing systems. Except as otherwise expressly provided herein, the Construction Contractor shall be responsible for implementing this Specification. The Construction Contractor shall ensure that the welding requirements set out in this Specification are complied with to the extent they are applicable. The Construction Contractor shall be solely responsible for ensuring that the Work is performed in strict compliance with all Environmental, Health and Safety Laws.

2 ACTS, REGULATIONS, LAWS, CODES AND STANDARDS

2.1 General

2.1.1 The latest edition of the following Acts, Codes and Standards shall form part of this Specification. It is the Contractor’s responsibility to be familiar with the latest editions of the Acts, Regulations, Laws, Codes and Standards that are necessary for the performance of the Work. These shall include but not be limited to the following:

• CSA Z662 – Oil and Gas Pipeline Systems

• Where regulated by Federal Standards, the National Energy Board – NEB Onshore Pipeline Regulations

• Alberta Pipeline Act and Regulations

• Other Provincial & Territories Acts, Regulations and Standards

2.1.2 Where CSA Z662 is referenced hereafter it shall mean CSA Z662 – Oil and Gas Pipeline Systems, all associated requirements of the Alberta Pipeline Act and Regulations, and the National Energy Board Onshore Pipeline Regulations as applicable. If there is a conflict between Acts, Regulations, Laws, Codes and Standards the most stringent requirement shall be met by Contractor. All conflicts must be referred to Enbridge for resolution.

2.1.3 The Contractor shall comply with the requirements of all applicable Acts, Regulations, Laws, Codes and Standards in performance of the Work.

3 RELATED TECHNICAL SPECIFICATIONS AND STANDARDS

3.1 General

3.1.1 The following Technical Specifications and Standards shall be read in conjunction with this Specification. The requirements of these documents shall become part of this Specification by reference herein.

• CPCS-SPEC-PIPELINE-001 - Pipeline Construction Specification

• CPCS-SPEC-NDT-003 – Non-Destructive Testing Specification


4 DEFINITIONS

4.1 General

4.1.1 Welding terms and definitions shall be in accordance with CSA Z662 and these Specifications as follows:

Arc Burns – An imperfection that results from an arc and consists of any localized remelted metal, heat affected metal, or change in the surface profile of any part of the parent metal away from the weld Bevel.

AUT – Automated Ultrasonic Testing. An automated or mechanized inspection system using ultrasonic inspection techniques.

Bridge Tack – Temporary weld used in the alignment of parts. Bridge tacks shall be made with qualified welders utilizing material preheat temperatures and consumables from a qualified WPS suitable for the materials to be joined. Bridge tacks shall only be applied to the prepared bevel groove.

Cold Weather Welding – Welding on pipe greater than 323.9 mm OD and greater than Grade 386 with ambient conditions inclusive of wind chill affects resulting in temperatures less than +5 C for more than 2 consecutive hours in a work day, forecasted or measured at the work site location, or otherwise defined by the Company.

Component – A pressure-retaining member of the piping, other than pipe.

Copper Contamination – Surface adhesion of thin amounts of copper that does not migrate into the weld metal.

Copper Inclusion – The presence of localized copper alloying as a result of direct deposition during the welding process (contact tip contact) or as a result of aggressive pick up from adjacent copper surfaces that results in dilution into the weld metal.

Counter Bore and Taper – A machining method utilized to transition pipe material of a greater wall thickness to that of the lesser wall thickness for welding.

Essential Change – A welding change that may affect the mechanical properties of the weld. Essential Changes are welding variables that have been altered outside the ranges specified in CSA Z662 or this Specification.

Final Tie-in – A permanent weld which will not be included in a hydrostatic test prior to the pipeline system being placed into service.

Final Weld at a Tie-in Location – The final weld completed at a tie-in location that will be included in a hydrostatic test. Welded in the ditch.

Interpass Temperature – The temperature of the weldment between weld passes, measured by calibrated contact thermometer or tempil-stick immediately before the start of any weld pass at a location 50 mm from a production weld joint or 150 mm from the edge of a weld-repair weld.

Mainline Welding – Pipeline welding activities performed on the pipeline right of way but not in the ditch.

Mechanized Welding – A welding method where the welding arc is moved along the weld joint by mechanical means.


Preheat – Application of a minimum specified heat to a weld joint prior to welding to ensure adequately slow cooling conditions.

Procedure Qualification Record – (PQR) Procedure Qualification Records are the summarized actual documented variables recorded during the qualification welding of test coupons to confirm the compatibility of consumables and techniques in the joining of materials typical for a given WPS. It also contains the mechanical and non-destructive test results of the tested specimens.

Production Welding – Production welding shall include all the welding completed in the performance of the Work including mainline, tie-in, weld-repair and field fabrication welding.

SMTS – Specified Minimum Tensile Strength

SMYS – Specified Minimum Yield Strength

Tack Welds – A temporary weld segment designed to hold a weldment in alignment prior to welding.

Tie-in – The welding together of completed pipe sections. Welded in the ditch.

Welding Data Sheet – (WDS) A single page summary of the WPS intended as quick reference for the welders and Inspectors to ensure familiarization of all the essential changes for welding. Project specific guidelines are given for the application of the welding, i.e., preheats, consumables, heat inputs.

Welding Procedure Specification – (WPS) A document providing, in detail, the required parameters for welding. The WPS takes the recorded variables from the development of the PQR and extends these into ranges of essential changes to be followed. This document is also termed as the ‘welding procedure’.

Welding Specification – A detailed document prescribing Company Guidelines, Policies and mandatory requirements when welding pipe and components

5 WELDING REQUIREMENTS

5.1 General

5.1.1 The Contractor shall have a documented Quality Program in place and a controlled copy of the Quality Program Manual shall be available to Company at the place of Work. The Company will conduct an audit of Contractor’s implementation of its Welding Quality Program.

5.1.2 WPS and welder qualifications shall be in accordance with the requirements of CSA Z662 and these Specifications.

5.1.3 No welding shall be performed unless the appropriate company approved Welding Data Sheet is on site.

5.1.4 WDS compliance remains the responsibility of the Contractor. Even though the WPS and WDS has been approved by the Company, the Contractor remains responsible for the technical performance of the qualified WPS and remains solely responsible for providing welds which are sound and suitable for the intended service.


5.1.5 The Contractor shall ensure that all persons under its direction involved with welding are fully aware of requirements for welding and all welders and related foremen are in possession of the appropriate WDS.

5.1.6 When welding of pipe materials Grade 550 or greater is required, the Company shall have final approval regarding essential variables or changes prior to WPS development or qualification.

5.1.7 Welding shall be performed using one or more of the following processes, either singly or in combination; shielded metal arc welding, gas metal arc welding or flux cored arc welding. Field Fabrication welding may also use the submerged arc welding process.

5.1.8 The Company may at its sole discretion provide the Contractor with a WDS representing a pre-qualified WPS for some or all pipe grades and diameters specified for the project for mainline, tie-in, weld-repair and field fabrication welding. The Contractor may propose their own WPS for approval by the Company. The Contractor shall be solely responsible for the performance and quality of welding performed using the authorized WPSs.

5.1.9 Any Contractor proposed WPS shall be in accordance with the requirements of this specification and shall be submitted to the Company for review and approval as follows:

5.1.9.1 Must be accompanied with a completed Project Specific WDS. Use W-17 Mechanized Welding Procedure Datasheet (MPPCS-FORM-WDSA-015) or W-17 Manual Welding Procedure Datasheet (MPPCS-FORM-WDSM-016) depending on the Welding methodology (mechanized or manual).

5.1.9.2 Must be accompanied with a completed W-13 Pipeline Project WPS Matrix (MPPCS-FORM-WPSA-014) outlining the intended use of the WPS /WDS.

5.1.9.3 Shall be submitted a minimum of 90 days prior to start of welder qualification.

5.1.10 A Contractor qualified WPS intended for mainline welding, weld-repair welding, or tie-in welding shall be validated using Company supplied project specific pipe to ensure suitability.

5.1.11 The Contractor shall designate a suitably qualified individual to monitor and document welding essential variables and shall provide to the Company on a daily basis the required documentation as outlined in section 11.4 - Contractor Documentation of Compliance.

6 WELD CLASSIFICATION

6.1 Tack Welds

6.1.1 Tack welds shall be performed by qualified welders. The Company approved qualified WPS for completed welds, including preheat requirements, shall be employed in producing tack welds.

6.1.2 Tack welds shall be of a sufficient number, size and quality, to maintain alignment and minimize the risk of breaking or otherwise compromising safety.

6.1.3 Tack welds shall only be permitted in the weld bevel area.


6.1.4 Bridge tacks shall be used for piping assemblies NPS 16 and larger. When bridge tack welds are used, they shall be completed using a Company approved low hydrogen WPS. Bridge tacks shall not be incorporated in the final weld. They shall be completely removed by grinding prior to filling of the joint. Bridging material shall be low carbon steel, generically similar to the base metals to be welded.

6.1.5 Root tacks may be used for piping assemblies smaller than NPS 16. Sound root tacks made according to a Company approved WPS for the joint may be incorporated in the final weld, provided complete penetration and fusion is obtained in the completed root pass.

6.1.6 Root pass segments deposited using external line up clamps, in accordance with a Company approved WPS, are not considered to be tack welds.

6.2 Groove Welds

6.2.1 The Company shall approve bevel preparations before the qualification of the WPS. For pipe and components NPS 2 and larger, welded joints shall be made with single or double groove butt joints.

6.3 Fillet Welds

6.3.1 It shall be permissible to use fillet welds in the form of socket welds for piping up to NPS 1.5 only. When this method is used, gap-o-lets or their equivalent shall be used in accordance with the manufacturers recommended practices. Fillet welds shall also be used for reinforcement of branch connection groove welds. The weld faces being joined shall be at an angle of 90° ± (1°) to each other unless otherwise specified by the Company.

6.3.2 Welded outlets shall be attached using fillet reinforced groove welds. Low hydrogen welding processes shall be used, except the root pass may be welded using cellulose electrodes. All subsequent weld passes shall be completed using a low hydrogen welding process and consumables. A minimum of 2 weld layers is mandatory. Where approved by the Company, the second pass may also be welded using cellulose electrodes.

6.3.3 Fillet welds shall be concave to slightly convex.

7 EQUIPMENT

7.1 General

7.1.1 All equipment shall be maintained in a condition that will ensure the continuity of operation and safety of personnel.

7.1.2 Welding equipment shall be of a size and type suitable to produce welds in accordance with this Specification and at a rate required to meet the project schedule. Any equipment which, in the opinion of the Company, is found not adequate for safe and productive welding construction, shall be replaced by the Contractor.

7.1.3 Inverter type welding power sources are preferred for welding tack rigs for root pass welding due to their ability to maintain constant and steady welding power.

7.1.4 Arc welding equipment shall be operated within the amperage, voltage, travel speed and heat input ranges specified in the Company approved WPS. Suitable means of


measuring welding amperage, voltage and travel speed shall be used by the Contractor to monitor compliance with the qualified WPS.

7.1.5 Grounding devices shall be securely fastened to ensure freedom from arcing during welding and shall be designed such that the grounding location is inside the joint bevel. The grounding type and location during WPS qualification should be consistent with field welding applications.

7.1.6 Roll welding techniques shall use a swivel type grounding device securely attached to the assembly piping. Grounding devices shall not be attached to fittings or valves unless approved by the Company.

7.1.7 Line up clamps shall be designed to avoid mechanical damage to the piping and to maintain alignment within specified tolerances.

7.2 Mechanized Welding

7.2.1 Mechanized welding equipment utilized for production welding shall be the same type and model used for WPS qualification. Pre-production welds will be performed utilizing any and all equipment to be utilized for production welding.

7.2.2 When using a Mechanized welding system featuring an external root process with internal copper back up, the internal clamp and backing system used in production shall also be the same make and type used during procedure qualification.

7.2.3 When software driven, digitally controlled welding power sources and Contractor proprietary digital interface are utilized for WPS qualification, the Contractor shall ensure all power source manufacturer and equipment supplier interface software revision numbers are maintained for production welding. This information shall be available to the Company representative during WPS qualification and also during production welding.

7.2.4 Welding shelters shall be provided for each welding station during external mechanized welding. Shelters shall provide protection from inclement weather, adequate lighting, electricity, ventilation and flooring (when suitable) to provide a safe working environment, with sufficient space for a welder and helper on each side of the pipe. A door shall be provided to access each side of the pipe.

7.2.5 If the AUT system selected for the project uses alignment bands that are the same as used for mechanized welding, the Contractor shall ensure an adequate number of welding/AUT bands are supplied so as not to impede daily AUT inspection work progress at no incremental cost to the Company.

7.2.6 The Contractor shall ensure that any proprietary weld metal transfer waveform technology, e.g. GMAW pulse transfer, is maintained as per the PQR. When automated welding controls are enabled during WPS qualification, the Contractor shall ensure that similar automation control is maintained for all production welding.

7.2.7 The use of auto work piece to contact tip height adjust and/or girth weld bevel tracking automation shall be specified in the PQR. If the auto work piece to contact tip height adjust and/or girth weld bevel tracking automation is not used during WPS qualification, it may be used during production welding without additional qualification but not vice versa.


8 MATERIALS

8.1 General

8.1.1 Only new filler metals and shielding gases consistent with the qualified WPS and having prior approval from the Company shall be used. The Contractor shall ensure that welding consumables from previous projects are removed from welding equipment prior to the commencement of Work on Company projects.

8.2 Consumables

8.2.1 Consumables shall be certified by the Canadian Welding Bureau as conforming to CSA Standard W48.1, W48.3, W48.4, W48.5 and W48.6; or having mechanical properties that meet the requirements of the above standards.

8.2.2 The Contractor will organize storage facilities and implement storage, handling and distribution procedures of welding consumables. The facilities shall be such that moisture pick-up, oxidation or shipping/storage damage to the welding consumables and the containers in which they are shipped does not occur. Consumables in opened containers shall be protected from deterioration and those that show signs of deterioration shall be disposed of. Any portion of a box or container found to be damaged or damp shall be cause for rejection of the entire box or container. All welds completed using suspect electrodes will be cut out and replaced at the expense of the Contractor. Storage, exposure periods and reconditioning of electrodes shall be in accordance with manufacturer’s recommendations.

8.2.3 Low hydrogen shielded metal arc welding electrodes, when removed from sealed containers, shall be stored in cabinets at temperatures in the 120⁰C to 150⁰C range before use. Low hydrogen SMAW electrodes exposed to atmospheric conditions for more than one hour shall be re-dried before use in accordance with that electrodes manufacturer's recommendations.

8.2.4 Low hydrogen GMAW, SAW, FCAW and MCAW wire consumables shall be stored as per manufacturer’s recommendations. Any consumables found with rust, moisture, damage and/or deterioration shall not be used. Any production welds completed with damaged or unsuitable consumables shall be removed and replaced at the expense of the Contractor.

8.2.5 The Company reserves the right to unilaterally prohibit the use of materials that it deems unsuitable for proper performance of the Work.

8.2.6 Welding Filler Metal Usage

8.2.6.1 Internal back-welding weld repairs shall be completed with low hydrogen consumables in accordance with the Company approved WPS.

8.2.6.2 Production welds shall be completed using the same brand name and CSA filler metal and flux classifications as used during WPS qualification unless otherwise approved by the company.

8.2.6.3 For submerged arc welding, all fluxes and electrodes shall be approved by the Company. The Contractor shall state within the intended WPS; the flux method of manufacture, the flux activeness and classification for approval by the Company.


8.2.6.4 All welds including butt welds, fillet welds, weld-repair welds and branch connection welds shall be made using a low hydrogen process. Cellulose coated electrodes may be used for the following weld applications:

a. The root pass and second pass of butt welds;

b. The root pass and second pass of through wall weld repairs;

c. All passes of butt welds joining pipe to pipe when the pipe SMYS is less than or equal to 386 MPa;

d. All passes of butt welds joining pipe to pipe when the pipe SMYS is greater than 386 MPa and the pipe wall thickness is less than 16mm nominal; or

e. All passes of pipe to component, and component to component welds where:

• Base metals are plain carbon ASME P-No. 1 steels with SMYS less than or equal to 386 MPa;

• Electrode SMTS is less than or equal to 480 MPa; and

• System pressure rating is PN 50 or lower.

8.3 Shielding Gases

8.3.1 Shielding gases shall be approved by the Company.

8.3.2 If carbon dioxide is used as a shielding gas, it shall have a purity of at least 99.5% and shall have a dew point of –34⁰ C or lower. Certificates attesting to this shall be provided by the Contractor.

8.3.3 Shielding gases shall be kept in the containers in which they are supplied and shall be stored adequately to prevent exposure to extremes of temperature. Gases shall not be intermixed in their containers and those that have questionable quality or are in containers that show damage shall not be used.

8.3.4 Gas flow regulators for the appropriate shielding gas shall be used and shall be kept in good working condition such that the shielding gas flow rate is as required by the approved WPS.

8.4 Pipe and Components

8.4.1 The Company supplied large diameter fittings, pipe bends, and pipe may be manufactured under standards having tolerances that may result in mismatch of weld ends due to variations in diameter, wall thickness and out-of-roundness. The amount of mismatch may require a back-welding WPS to be implemented. This is not an abnormal condition, particularly on heavy wall thickness material.

9 QUALIFICATION OF WELDING PROCEDURE SPECIFICATIONS

9.1 General

9.1.1 For WPS qualification purposes, welding operations have been classified as follows:

• Mainline welding;


• Tie-in welding;

• Mainline and tie-in weld-repair welding, including back welding;

• Field fabrication welding; and

• Field fabrication weld-repair welding.

9.1.2 Approved and qualified WPS shall be developed by the Contractor in accordance to the requirements of CSA Z662 and this Specification. The Company may at its sole discretion provide the Contractor with a pre-qualified WPS for some or all pipe grades and diameters specified for the project. The Contractor shall be solely responsible for the performance and quality of welding performed using the authorized WPS.

9.1.3 It is the intent of Enbridge that welding procedure qualification for pipeline welding replicates the intended welding practices to be implemented in production. Qualification welding shall simulate production welding as closely as practical including the effects of ambient conditions and pipe stresses.

9.1.4 Unless specifically approved otherwise by the Company, all SMAW bevel preparations shall be 30 ° (+5°, -0°).

9.1.5 Processes, bevel design and alignment, consumables and welders used for WPS qualifications shall be approved by the Company, and shall be in accordance with CSA Z662, this Specification and referenced documents. WPS qualification essential changes shall be as defined by CSA Z662 and this section of this Specification. In addition to the requirements specified in CSA Z662 the following essential changes shall be applied during WPS qualifications:

9.2 Electrode Selection

9.2.1 SMAW and Mechanized PGMAW/GMAW Welding consumable selections should be in accordance with Table 1A and 1B. Alternative consumable selections shall be approved by the Company.

9.2.2 FCAW, MCAW, and SAW consumable selection shall be subject to Company approval.

9.2.3 Welding consumable tensile strength levels shall be specified by the Company for pipe base materials greater than Grade 483 MPa

Table 1A – For Material Grade > 386 MPa < 483 MPa

APPLICATION SMAW ROOT PASS

SMAW SECOND

PASS

SMAW FILL/CAP

PASS

MECHANIZED (P)GMAW ALL PASSES

Maingang, Poorboy, Section & Tie-ins

E6010 EXX10-G or P1

EXX10-G or P1

As Determined by Company

Weld-repairs Through-wall E6010 EXX10-G or

P1 E8018-C3 N/A

Weld-repairs Partial Through-wall NA NA E8018-C3 N/A

Backweld Weld-repairs E8018-C3 N/A N/A As Determined by Company


Table 1B – For Material Grade ≤ 386 MPa

9.3 Maximum Travel Speed

9.3.1 Root passes completed utilizing the SMAW process shall be limited to a maximum of 457 mm/min (18 inches/min.

9.4 Minimum Interpass Temperatures

9.4.1 Interpass temperatures shall be qualified in accordance with Table 2 below.

9.4.2 Consideration may be given by the Company to lower interpass temperature values if the root pass is deposited with a low hydrogen welding consumable or process.

9.4.3 Mechanized GMAW/PGMAW techniques shall be qualified using a minimum interpass temperature of 50ºC. Consideration should be given to qualify an additional high interpass (150-180°C) temperature.

9.4.4 Field Fabrication welding shall have a minimum interpass temperature of 150°C for all piping wall thicknesses greater than 12.7 mm.

Table 2 –Minimum Interpass Temperatures

Wall Thickness mm Outside Diameter – mm

60.3-88.1 114.3-219.1 273.1-323.9 355.6-406.4 Over 406.4

Under 4.78 38°C 38°C 38°C 66°C 93°C 4.78 to 9.53 38°C 38°C 66°C 93°C 121°C

9.54 to 12.70 38°C 66°C 93°C 121°C 121°C 12.7 to 23.0 66°C 93°C 121°C 121°C 121°C

9.5 Maximum Time Interval between Weld Passes

9.5.1 Maximum time intervals shall be specified in the WPS as suggested below in Table 3. Any specified time interval beyond those specified in table 3 shall require qualification and will be limited to a maximum of the duration recorded during procedure qualification.

APPLICATION SMAW ROOT PASS

SMAW SECOND PASS

SMAW FILL/CAP PASS

MECHANIZED GMAW ALL

PASSES Maingang, Poorboy, Section & Tie-ins E6010 EXX10-G or P1 EXX10-G or P1 N/A

Weld-repairs Through-wall E6010 EXX10-G or P1 EXX10-G or P1 N/A

Weld-repairs Partial Through-wall NA NA EXX10-G or P1 N/A

Backweld Weld-repairs E7018-1 N/A N/A N/A


Table 3 – Maximum allowable Time Intervals Between Weld Passes

TIME INTERVAL

10 MINUTES MAXIMUM ROOT PASS TO SECOND PASS

1 HOUR MAXIMUM SECOND PASS TO FILL PASS

24 HOURS MAXIMUM FILL PASS TO CAP PASS

9.6 Mainline Welding Procedure Specification Qualification

9.6.1 During WPS qualification, field weld interpass temperature cycles shall be simulated as closely as possible. At the completion of the second pass and the completion of the first fill pass, welds shall be allowed to cool to ambient temperature. Welds shall then be reheated to maintain minimum interpass temperature prior to depositing further weld passes.

9.6.2 Mechanized welding procedures shall specify a maximum cap width. This cap width may be calculated as 6mm beyond the groove width at the top of the joint or as proven during weld procedure qualification.

9.6.3 Mechanized welding procedures utilizing an external root process with copper back up shall specify maximum tolerances for root gap and misalignment during fit-up. These maximum values shall be proven during procedure qualification to ensure no risk of copper inclusion during field welding. Changes in the maximum gap and misalignment shall be essential changes requiring re-qualification.

9.6.4 As a part of the mechanized WPS qualification process, a specified number of consecutive qualification welds (the number of welds will be determined by the Company) will be non-destructively tested. These welds shall meet the requirements of the defect acceptance criteria defined by the Company.

9.7 Mainline Weld-Repair Welding Procedure Specification Qualification

9.7.1 The Weld-repair Welding Procedure qualification shall consist of:

• A simulated through wall repair of a girth weld; and

• A simulated back-weld repair of a girth weld, if applicable.

9.7.2 Only low hydrogen welding consumables shall be permitted for back welding. SMAW and GMAW back welding WPS’s shall be inspected to established workmanship criteria or other criteria defined by the Company. For back welds using semi-automatic GMAW, the essential changes utilized in the qualified mechanized WPS shall match the semi-automatic WPS.

9.7.3 Weld-repair welds shall be completed as follows and a drawing of the test assembly is shown in Figure 1

9.7.3.1 Q1 and Q3 shall be a through wall weld-repair simulation.

9.7.3.2 Q2 and Q4 shall be a back-weld weld-repair over a root pass excavation approximately 1.5 mm deep and 150 mm long, using low hydrogen consumables.


9.7.4 Weld-repair WPS shall be completed using 121⁰C minimum preheat and interpass temperature.

9.7.5 The fills and cap passes of weld-repair welds shall be made using low hydrogen welding processes except for materials with Grades up to 386 inclusive where cellulose consumables are permitted. The root pass shall be completed using E6010 electrodes. The second pass may be welded with cellulose electrodes.

9.7.6 Each through-wall weld-repair WPS shall be qualified with both non-destructive and destructive tests as specified in Clause 9.11 and 9.12 of this Specification. An equal number of specimens shall be removed from each through-wall quadrant. For wall thickness greater than 12.7 mm, four side bend specimens shall be substituted for the face and root bends.

9.7.7 Back weld weld-repair qualifications shall be mechanically tested by completing a transverse hardness survey as described in clause 9.12.1.3.

9.8 Tie-in WPS Qualification

9.8.1 If a mainline welding WPS is deemed unsuitable for tie-in welding, then a tie-in welding WPS will be developed and qualified.

9.9 Field Fabrication WPS Qualification

9.9.1 Field fabrication WPS shall be qualified according to these Specifications and:

9.9.1.1 CSA Z662; or

9.9.1.2 ASME Boiler and Pressure Vessel Code Section IX (hereinafter referred to as ASME IX) with CSA Z662 compliance.

9.9.2 Field fabrication welding shall have a minimum interpass temperature of 150⁰C for all piping wall thicknesses greater than 12.7 mm.

9.9.3 Welding processes used for field fabrication welds are restricted to SMAW, GMAW, FCAW, and SAW.

9.9.4 Field fabrication WPS qualification tests shall include additional examination in accordance with 9.12.1.2 and 9.12.1.3.

9.10 Field Fabrication Weld-Repair WPS Qualification

9.10.1 If the Contractor proposes a field fabrication weld-repair WPS that is different from that qualified for use on mainline and tie-in welds, the Contractor shall qualify the proposed field fabrication weld-repair WPS in the same manner as described for mainline and tie-in weld-repair WPS.

9.10.2 Minimum preheat and interpass temperature for a field fabrication weld-repair WPS shall be 121⁰C except as specified in 9.4.4.

9.11 Non-destructive Testing of WPS Test Coupons


9.11.1 Immediately after welding, each WPS qualification test coupon shall be visually examined and fully radiographed or ultrasonically tested. Non-destructive techniques shall be similar to those to be used for inspection of production welding. Acceptance criteria shall be as stated in CSA Z662 Section 7 unless otherwise directed by the Company. Welding procedure specifications previously qualified in accordance with ASME Section IX without being fully radiographed or ultrasonically tested before destructive testing may be approved for use.

9.11.2 All SMAW WPS qualification test coupons shall be left for at least 18 hours prior to NDT. After this time period:

9.11.2.1 Each WPS qualification test coupon shall be completely re-evaluated using the non-destructive testing techniques, radiographic or ultrasonic, used for the initial evaluation.

9.11.2.2 Each root pass shall be examined for evidence of cracking by the magnetic particle method, using wet fluorescent or black and white colour contrast indicating mediums.

9.12 Destructive Testing of WPS Qualification Test Coupons

9.12.1 Following successful completion of non-destructive examinations, WPS test coupons shall be destructively tested according to the requirements of CSA Z662, or ASME IX as applicable, and the following requirements.

9.12.1.1 Non-destructive testing shall not be used to define sound areas of the weld for destructive testing.

9.12.1.2 Impact tests shall be conducted on the weld metal and HAZ of each WPS qualification test coupon. An impact test shall consist of the breaking of three impact specimens at or below the test temperature designated by the Company. Impact specimens shall be of the largest obtainable size and shall be removed transverse to the weld axis. Minimum absorbed energy for full size samples shall be an average of 27 Joules with no one value less than 20 Joules. This may be reduced for sub size samples in accordance with the reduction ratios provided by CSA Z245.1. Charpy impact tests shall be conducted according to the ASME Boiler and Pressure Vessel Code, Section VIII, Division 1, Paragraph UG-84, using samples obtained from approximately the three o'clock position. Impact test reports shall include absorbed energy and shear area. For mechanized welding, energy absorption for weld metal specimens shall not be less than 40 Joules. For mechanized welding processes, crack tip opening displacement (CTOD) tests shall be performed and such tests will be arranged by the Company. Testing shall be performed in accordance with CSA Z662 Annex K at a test temperature to be defined by the Company. The measured CTOD and related test data such as load-displacement curves shall be reported for each specimen.

9.12.1.3 A cross-sectional hardness survey shall be made 1 mm below each of the inside diameter and the outside diameter surfaces using a Vickers Diamond Pyramid Indenter with a 10 kg load. The survey shall be taken across the weld metal, both coarse grained HAZ and parent metal on both sides of the weld. HAZ indentations shall be placed in the hardest appearing structures, such as those located adjacent to the toe of the cap or root pass, even if these structures do not coincide precisely with the line of the survey. Maximum hardness shall be 305 Hv for manual and semi-automatic welding processes and 325 Hv for mechanized process. For mechanized welding processes, isolated readings up to 350 Hv may


be accepted provided that two additional tests in the same area are 325 Hv or less.

9.12.1.4 For mechanized welding processes intended for qualification in accordance with CSA Z662 Annex K, two transverse weld tensile test specimens shall be machined from a location adjacent to one of the tensile test specimens required in CSA Z662. The specimens shall be prepared in the same manner as required by CSA Z662 except that the reinforcement shall be removed from both sides of the specimen. The specimen shall be pulled in the same manner as required for tensile testing of the specimens in CSA Z662. The yield strength of each specimen shall be equal to or greater than the specified minimum yield strength of the pipe material.

9.12.1.5 The facility chosen by the Contractor for mechanical testing, and the metallurgist of record shall be approved by the Company prior to its use.

10 WELDER QUALIFICATION

10.1 General

10.1.1 Each welder employed by the Contractor to work on the pipeline system shall be skilled and qualified for the type and methods of welding they will do, in accordance with CSA Z662, and this Specification.

10.1.2 Welders shall qualify by demonstrating their ability to produce acceptable welds in accordance with the Company approved WPS for the particular welding configuration or application to be used in production welding.

10.1.3 No welder shall carry out any phase or type of welding for which they have not been tested and accepted by the Company as qualified.

10.1.4 Welders failing to meet the minimum requirements of this Specification after testing shall not be permitted to retest for a period of thirty days.

10.1.5 Welders qualifying for field fabrication welding shall meet the requirements of the ASME IX or CSA Z662 as required by the applicable WPS.

10.1.6 Welders intended for use at tie-ins shall also be qualified for weld-repair welding, unless otherwise authorized by the Company.


Figure 1: Weld-repair WPS Qualification Test Assembly

10.1.7 No welder qualification shall be permitted on field production welds unless preauthorized in writing by the Company.

10.2 Test Requirements

10.2.1 Each welder and welding operator shall be qualified by both visual and radiographic or ultrasonic testing as permitted by CSA Z662. Acceptance criteria shall be as stated in CSA Z662. Each WPS qualification test coupon shall then be set aside and retained for further examination by the Company. Such further examinations are not considered part of the performance qualification tests.

10.2.2 Pipe material used for welder qualification testing will be provided by the Company.

10.2.3 Before starting qualification tests, welders shall be given training sufficient to allow them to obtain adequate skills to produce acceptable welds on a consistent basis.

10.2.4 All test welds shall be witnessed by the Company and failure to comply with the WPS shall be cause for rejection.

10.2.5 The Contractor shall notify the Company at least 72 hours prior to carrying out welder qualification tests to allow the Company to assure witness of the welding and arrange for Company qualified NDT.

10.2.6 Test welds shall be produced in accordance with the Company approved WPS, by each welder, and shall be radiographically and/or ultrasonically inspected using techniques similar to those to be used for inspection of production welding.

10.2.7 For the purpose of welder qualification testing with an outside diameter greater than 323.9 mm, the terminology “weld” shall mean one half of the total pipe circumference and pipe with an outside diameter 323.9 mm or less, the terminology “weld” shall mean the entire pipe circumference.

10.2.8 For mainline welding process/techniques other than conventional manual SMAW, consistency shall be based upon, and qualification shall be dependent upon, the welder

Q1 Through-

wall

Q2 Back Weld

Q3 Through-

wall

Q4 Back Weld


completing three successive acceptable test welds. Two qualification welds shall be completed on the mainline project thickness and one weld shall be completed on the heaviest pipe thickness that will be welded. When multiple mainline wall thicknesses are encountered, any of the mainline thicknesses may be selected by the Company for qualification purposes.

10.2.9 For conventional manual SMAW, consistency shall be based upon, and qualification shall be dependent upon, the welder completing one acceptable test weld.

10.2.10 For mechanized welding systems that use external root pass techniques, the welder shall qualify by welding all weld passes.

10.2.11 For mechanized welding systems that use internal root pass techniques, the welder shall qualify by welding all external weld passes.

10.2.12 For mechanized welding with an internal line up clamp, operators/welders operating the internal welding equipment shall be suitably trained by the Contractor on the safe operation of the equipment. These operator/welders shall be qualified on the root pass of the mechanized welding line up clamp as well as all external weld passes.

10.2.13 Welders performing weld-repairs shall be qualified in accordance with the approved through wall weld-repair WPS and shall simulate a ‘full through wall’ weld-repair. This test shall also qualify them for ‘partial through wall’ weld-repairs. A separate qualification shall be performed for back-weld weld-repairs.

10.2.14 The full through wall weld-repair welding test shall consist of simulating two full-through-wall weld-repair welds on a previously completed test weld, with the pipe in the horizontal - fixed position. Two sections, one located approximately at the 12 – 2 o’clock position and one located approximately at the 4 – 6 o’clock position, shall have the weld metal removed by grinding to a depth that permits re-welding of the root pass. The width of the weld-repair section shall be a maximum of 3.2 mm wider on each side (toe) of the original groove. Each section ground out shall be subsequently repaired from the root pass through to the cap pass, using an approved WPS.

10.2.15 The back-weld weld-repair welding test shall consist of simulating two back-weld weld-repairs on a previously completed test weld, with the pipe in the horizontal-fixed position. Two sections, one located approximately at the 10 – 12 o’clock position and one located approximately at the 6 – 8 o’clock position shall have the weld metal removed by grinding to a depth that permits re-welding of the root pass. The width of the weld-repair section shall be approximately that of the original root pass.

10.2.16 The length of each weld-repair segment is dependent on pipe outside diameter as shown in Table 4.

Table 4: Minimum Length of Weld Repair Segments Pipe Outside Diameter OD Minimum Length of Weld-Repair Segments

Greater Than 323.9 mm 150 mm

323.9mm or Less 100 mm

NOTE: Small diameter pipes may require the use of more than one test weld to complete the two segments.


10.2.17 Weld-repair welders shall be evaluated according to the visual and radiographic or ultrasonic requirements of CSA Z662, or the destructive testing requirements of the Company.

10.2.18 The Contractor shall prepare and maintain a list of welders, their qualifications in accordance to which WPS tested, and the date of qualification, which shall be updated after any change of welding personnel and submitted to the Company.

10.2.19 Each welder shall be assigned a unique number to identify their welding. No other welder shall receive the same number and if a welder is terminated or leaves the project the number shall not be reassigned. The Contractor shall provide a list of qualified welders with corresponding numbers to the Company.

10.2.20 If, in the opinion of the Company, the failure of a welder to pass a test was because of unavoidable conditions or conditions beyond the welder’s control, such a welder may be given a second opportunity to qualify. No further retest shall be given.

10.2.21 A welder may be required to re-qualify at any time, if in the opinion of the Company, there is any reasonable doubt about the ability to produce acceptable welds.

10.2.22 Welders who have already qualified for mechanized welding on the project and have not welded for a period of 90 days from their last production or qualification weld shall be required to complete a check test. Check tests shall consist of a single weld, inspected with the project specific acceptance criteria. Failed check tests shall require additional welder training and a second check test. A failed second check tests shall require complete welder re-qualification.

11 PRODUCTION WELDING

11.1 General

11.1.1 The welding of piping in accordance with this Specification shall be performed using qualified welders in accordance with the Company approved qualified WPS. Production welding shall not be performed when conditions encountered exceed the limits stated in the WPS.

11.1.2 It is required that all welders receive a copy of each WDS that applies to their particular welding duties to ensure they are aware of what practices must be followed. All welders shall have a copy of their particular WDS in their possession except that for mechanized welding the WDS shall be posted inside the welding shacks.

11.1.3 The Contractor shall suitably train their personnel in the use and safety aspects of the facing/bevel machine before starting production welding.

11.1.4 When manually welding externally coated pipe, the Contractor shall place a sheet of non-flammable material with a minimum width of 400 mm on each side of the weld to prevent weld spatter from damaging the coating. When using mechanized welding processes, the Contractor shall place a sheet of non-flammable material with a minimum width of 400 mm on the side of the weld opposite the welding band.

11.1.5 Subsequent to initial NDT inspection, and at the Company’s discretion, production welds may be held for 1 additional day for post weld inspection at no incremental cost to the Company.

11.1.6 Tie-in welds shall not be NDT inspected until they are cool to touch.


11.1.7 To facilitate NDT and to allow access across the Construction Right-of-Way to animals and landowners, the Contractor shall be required to provide open-ended sections as approved by the Company.

11.1.8 Manufacturer’s pipe joint numbers, pup length and heat numbers shall be transferred to each length of pipe (pup), on both the ID and OD, cut from any full joint of pipe. Identification shall be made by suitable marking using indelible permanent marking crayons.

11.2 Weather Conditions

11.2.1 Welding shall not be performed when in the opinion of the Company the quality of completed welds could be impaired by prevailing weather conditions including, but not limited to: extreme cold, rain and snow, blowing sand or high winds. Windbreaks, of a type that will provide adequate protection to the weld and welder, shall be used when, in the opinion of the Company, such equipment is required.

11.2.2 If using gas shielded welding processes all welding shall be carried out within welding shelters designed to protect the welding/work environment from being exposed to detrimental ambient conditions.

11.2.3 If using gas shielded welding processes, skidding of the pipe shall permit complete enclosure of the welding/work environment

11.3 Cold Weather Welding

11.3.1 When cellulosic consumables are used for any pass of a weld made during cold weather construction, as defined by this specification, the following additional requirements shall apply to the weld in its entirety:

11.3.1.1 Double up welders on fill and cap pass (i.e. brother-in-law) all diameters greater than 323.9 mm OD.

11.3.1.2 Completed welds and an area extending at least 50 mm on each side of the weld, shall be tightly wrapped with company approved thermal blankets. Removal of blankets is not permitted until the weld and surrounding pipe area has reached a temperature of 50°C

11.4 Contractor Documentation of Compliance

11.4.1 The Contractor shall continuously monitor and document bevel dimensions, based on the dimensions provided within the Company approved WPS. The frequency of checking and form of documentation shall be established by the Contractor and shall be submitted for approval by the Company before the start of production welding. As a minimum the bevels shall be checked 3 times daily, and the frequency increased if problems are found or welding problems occur due to bevel preparation.

11.4.2 The Contractor shall use calibrated monitoring equipment for the measurement of welding amperage and voltage. Calibration shall be performed before production welding and shall be re-calibrated every 12 months minimum. Calibration records shall be provided to the Company for review and acceptance.

11.4.3 The Contractor shall continuously monitor welding to ensure compliance with the requirements of this Specification. Documentation of compliance verifications shall be


made and shall be submitted to the Company on a daily basis. The following minimum daily documentation shall be completed by the Contractor.

11.4.3.1 Mainline Welding (Including Maingang, Poorboy and Section Crews)

FRONT-END (Pipe gang): Two welds; from each weld take one root pass parameter set plus one second pass parameter set. In addition, documentation of preheat and interpass temperature for the circumference of the weld is required.

BACK-END (Firing Line): Two welds; from each weld take one fill pass parameter set plus one cap pass parameter set. In addition, documentation of preheat and interpass temperature for the circumference of the weld is required.

MECHANIZED WELDING: in addition to the above requirements for front-end and back-end parameter checks, data acquisition files recording welding parameters shall be backed up daily to an external drive and saved as a file identifying the date of production. The external drive(s) shall be turned over to the company whenever requested and finally upon completion of welding operations on the project.

NOTE: Parameter set shall include the amperage, voltage, travel speed and calculated heat input. On back-end rotate through all weld passes weekly. Identify all parameter locations by weld number, weld pass and weld procedure used. Other data shall be documented including but not limited to wire heat number, gas types and flow rates, power source manufacturer and equipment supplier interface software revision numbers, as applicable.

11.4.3.2 Weld-Repair Welding

One weld, the amperage, voltage, travel speed (if possible) and calculated heat input. Identify all parameter locations by weld number, weld pass and weld procedure used. In addition documentation of the preheat is required. Other data shall be documented including but not limited to electrode classification handling and storage.

11.4.3.3 Tie-In Welding

One weld, the amperage, voltage, travel speed and calculated heat input for any two weld passes. Rotate through all weld passes weekly. Identify all parameter locations by weld number, weld pass and weld procedure used. Other data shall be documented including but not limited to preheat/interpass temperature for the circumference of the weld and electrode classification.

11.4.4 The Company reserves the right to change the daily documentation requirements if quality or other issues dictate a change would be beneficial to resolving welding problems or situations.

11.5 Welding Performance Requirements

11.5.1 The Contractor shall take every precaution to produce welds that meet the requirements of these Specifications. Should the number of welds failing to meet these Specifications exceed 15 percent, based on total production for one full working day, the Company reserves the right to suspend the welding operation until the problem is


identified and corrective measures are submitted by the Contractor for the Company's approval at no incremental cost to the Company.

11.5.2 The Company reserves the right to unilaterally remove a welder from production, who in the opinion of the Company is responsible for an unacceptable level of defects or weld-repairs.

11.6 Preparation of Pipe

11.6.1 Preparation of pipe shall require that all piping ends that are to form a part of the welded joint shall be cleaned to sound metal immediately before welding to ensure complete removal of all paint, grease, oxide, rust and any other extraneous matter. Cleaning shall extend for at least 25 mm from the piping edges on both internal and external surfaces.

11.6.2 The Contractor shall re-cut, re-bevel and re-clean, all pipe ends in accordance with the Company approved WPS and this Specification, as may be necessary to maintain correct alignment and spacing at no incremental cost to the Company unless previously agreed to in writing.

11.6.3 All bevels shall be cut straight and even and be finished smooth and uniform with no rough surfaces.

11.6.4 Stockpiled pipe will be provided with longitudinal and spiral DSAW seams ground smooth (+0.50 mm, -0 mm) and pipe coating removed for a distance of 120 mm from the bevel edge, with a smooth transition to the weld reinforcement.

11.6.5 Where factory pipe ends have been removed, the longitudinal and spiral seam welds shall be ground smooth (+0.1 mm, -0 mm), both internally and externally, and the coating shall be removed for a distance of:

11.6.5.1 12 mm from the edge of the bevel if the joint is intended for manual welding; or

11.6.5.2 120 mm from the edge of the bevel if the joint is intended for mechanized welding and/or AUT inspection.

11.6.6 Bevelled ends shall comply with the angles, dimensions and geometry specified in the qualified and Company approved WPS.

11.6.7 For mechanized GMAW all field bevels shall be cut by a machine tool (bevelling/milling cutter). All other bevels shall be made with a machine tool or a mechanical flame cutting machine. Hand bevelling is not permitted. Free-hand manual flame cutting or bevelling is not permitted.

11.6.8 Any lamination or split end discovered on the bevelled end of a pipe or pup, before or during welding, shall be completely removed followed by re-bevelling to the requirements of the Company approved WPS. Laminations or split ends removed from piping components shall be provided to the Company for disposition.

11.6.9 Burns, small scores, indentations, burrs, gouges, dents, unfinished machining or other defects within the joint preparation area shall be removed by light filing or grinding to the satisfaction of the Company. If a satisfactory joint preparation cannot be achieved by blending out discontinuities with a grinder, the bevel shall be re-prepared.

11.6.10 No welding repair of bevels shall be permitted.


11.6.11 Preparation for welding of pipes of different wall thickness shall be in accordance with the requirements of this Specification. Mechanized welding of different nominal wall thickness pipe shall be evaluated using standards of acceptability specified in CSA Z662 Clause 7 as applicable.

11.6.12 If the difference in nominal wall thickness of adjoining pipes exceeds 1.0 mm, transitioning of the thicker pipe down to the thinner pipe shall be required. The design of such transitioning shall accommodate the welding technique and the non-destructive examination technique, without any additional set-up or delays. The Contractor shall note that a counter bore and taper design is the required transition design for all welds inspected using an ultrasonic inspection technique.

11.6.13 When back bevel tapered transitions are permitted by the Company, radiographic weld inspection testing techniques are required. Final radiographic inspection shall not be completed until a minimum 18 hours after the completion of the weld.

11.6.14 For welding applications that are inspected using ultrasonic inspection, the Contractor shall clean the weld and surrounding surface area 100 mm on each side of the weld to a surface finish suitable for ultrasonic inspection.

11.6.15 For final tie-ins joining pipe with unequal nominal wall thickness, a minimum 100 mm counter bore with a 30° taper shall be used, subject to compliance with strength and thickness requirements. All transitioning designs shall be approved by the Company before the start of production welding.

11.6.16 All counter bore and tapered and back bevel tapered transitions shall be reported to the company prior to welding to permit the Company to visually inspect the preparation. All transitions shall be visually inspected and approved by the Company.

11.6.17 During pipe end preparation work, all waste metal shall be gathered and removed from the Construction Right-of-Way on a daily basis for appropriate disposal. When a portable machine tool is being used, this Work shall be done over a tarpaulin laid out to collect the shavings. When a bevelling torch is used, the metal pieces shall be picked up after each cut. An alternative magnetic pick up procedure may be required if the tarpaulin collection method is found by the Company to be unsuccessful.

11.7 Alignment, Fit Up and Support

11.7.1 Line-up clamps shall be used in accordance with the approved WPS. Care shall be taken when using line-up clamps to minimize stress at the pipe ends.

11.7.2 Where mainline welding is performed using internal line-up clamps, external line-up clamps shall only be permitted on pipe sections containing 8 pipe joints or less, unless otherwise permitted by the Company.

11.7.3 External line-up clamps shall be used for tie-in welds. Root pass segments shall be spaced uniformly around the full circumference for the joint and, where practical, shall have a cumulative length of at least 50% of the joint circumference before clamp removal.

11.7.4 Internal line-up clamps shall be used for all mainline production welding for pipe with OD greater than or equal to 323.9 mm and shall not be removed until, as a minimum, the root pass has been 100% completed.


11.7.5 Alignment of abutting ends shall minimize the offset between surfaces. For pipe of the same nominal wall thickness, the maximum offset shall be 1.6 mm. Any greater offset, provided it is caused by dimensional variations, shall be distributed around the circumference of the joint with the least offset at the top and bottom of the joint.

11.7.6 The use of wedges to correct minor out-of-roundness and high-low shall not be permitted unless approved by the Company.

11.7.7 Longitudinal and skelp end welds in adjacent lengths of welded pipe shall be offset by a minimum of 50 mm. Longitudinal seams shall be located at the top quadrant of the pipe, except for bends.

11.7.8 Materials such as bevel shavings, dirt, snow, ice, water and other foreign substances shall be removed from the pipe before alignment for welding.

11.7.9 Contamination of the weld by detrimental materials welded into the weld joint shall be cause for rejection of the weld affected.

11.7.10 All branch type attachments shall be located at least 50 mm from circumferential or longitudinal seam welds unless otherwise approved by the Company.

11.7.11 Movement of the pipe joint shall be minimized until the root pass is 100% completed and, for SMAW welding, the second pass has been made for at least the specified minimum distance required by nominal pipe size on the bottom of the weld joint (see clause 11.8.1). Lifting of the pipe to facilitate set-up of the subsequent joint shall only be permitted if the root pass plus the minimum distance of second pass are completed on the bottom of the weld joint.

11.7.12 During the final weld at a tie-in location, the pipe shall be fully supported by sidebooms until a minimum of one fill pass is completed. Further, the pipe shall remain fully supported by skidding or other Company approved methods such that the pipe is not moved until all of the fill passes are completed.

11.7.13 Final tie-in welds shall be fully supported such that the pipe is not moved until all weld fill passes are complete.

11.8 Removal of Line-up Clamps

11.8.1 When manual welding, internal line-up clamps shall not be removed until the second pass has been completed. for the minimum length indicated in Table 5. This length of second pass shall be centered across the bottom of the weld (~5:00 to ~7:00 location)

Table 5: Minimum Lengths of Second Pass Prior to Clamp Removal Pipe Outside Diameter OD Minimum Length of Second Pass

610 mm and Greater 250 mm Less Than 610 mm to 323.9 mm Inclusive 150 mm Less Than 323.9 mm Not Required

11.8.2 The requirement for the minimum length of second pass deposited prior to movement of the pipe or removal of line-up clamp may be waived by the Company when using mechanized GMAW or for smaller diameter applications.


11.9 Preheating

11.9.1 Preheat shall be measured by calibrated contact thermometer or tempil-stick immediately before the start of welding.

11.9.2 For production welds the preheat temperature shall extend around the entire circumference of the pipe and shall be measured at locations with a minimum distance of 50mm from the production weld. For weld-repair welds the preheat temperature shall be evenly distributed around the weld-repair and shall be measured at a location with a distance of 150mm from the weld-repair area.

11.9.3 Preheating of the pipe shall be performed using the Company approved methods as specified on the approved WPS.

11.9.4 Preheating of the pipe shall be such that the minimum interpass temperature is maintained on the entire circumference of the joint throughout the completion of the welding pass.

11.9.5 During root and second pass welding, under no circumstances shall the minimum temperature get below the minimum interpass temperature from the start of the root pass until after the completion of the second pass. Reheating is permitted before the start of the fill/cap passes

11.9.6 During completion of the weld, the joint shall be maintained at a temperature between the minimum and maximum interpass temperatures and shall be checked using temperature indicating crayons, or direct contact thermometers, immediately before and during the full welding operation. No welding shall take place unless the minimum interpass temperature is maintained. The heating of local areas (hot spots) above the upper limit of preheating, as identified on the approved WPS, is not permitted.

11.9.7 When welding on valve assemblies preheating close to valve bodies shall be conducted in accordance with valve manufacturer’s Specifications. As a minimum, insulation or other non-flammable material shall be placed in both ends of the valve bore to protect seals and seats from weld spatter and debris.

11.9.8 When welding on valve assemblies preheat and weld interpass temperatures shall be restricted to the weld zone to ensure that valve seats are not damaged.

11.9.9 When welding on valve assemblies preheating of valves shall be applied on the outside surface of the valve. Heating from the inside shall not be permitted.

11.9.10 The Contractor shall ensure that the application of preheat does not damage the pipe coating. Care shall be taken to prevent overheating, and no part of the area shall be heated more than 200°C. Should over heating of the pipe material occur, in the opinion of the Company, the damaged pipe end shall be cut off as a pup and re-bevelled with the appropriate bevel configuration at the expense of the Contractor.

11.10 Welding Sequence

11.10.1 Weld layer sequencing shall be completed as qualified within the Company approved WPS.

11.10.2 The minimum number of root pass and second pass welders shall be two for pipe greater than 323.9 mm OD. One root bead and one second pass welder may be used for pipe 323.9 mm OD and less.


11.10.3 Root pass welding shall only commence after ensuring that the parts to be joined are adequately secured against movement.

11.10.4 The second pass shall start as soon as possible after the root pass and in any case within the specified time period stated on the Company approved WPS.

11.10.5 Consideration shall be given by the Company to longer time intervals between the root pass to second pass provided the root pass is deposited with a low hydrogen consumable, and the extended time interval was qualified during WPS qualification.

11.10.6 Each bead shall be thoroughly cleaned of scale, dirt, slag, etc. before the application of subsequent beads. The completed surface of the weld shall be thoroughly power-brushed clean of all spatter and slag and the reinforcement shall blend smoothly with the adjacent pipe surface. The top cap button shall be ground to blend smoothly into the remaining weld pass and shall not be permitted to exceed the maximum heights as stated below.

11.10.7 Continuity of the pipe welding operation shall be maintained and at no time shall the root pass and second pass operations be more than 1 hour ahead of the subsequent weld passes. Unless approved by the company and qualified accordingly during procedure qualification.

11.10.8 Mainline welding shall continue, without detrimental pipe movement until a minimum of 3 weld passes are completed or 2/3 of the weld thickness is filled, whichever is the greatest and, shall not be left incomplete longer than 24 hours. Where it can be anticipated that welds would be left longer than 24 hours they shall be filled to completion, unless otherwise approved by the Company. The number of uncapped welds at the end of the day shall be limited to one set up, unless otherwise approved by the Company. Partially completed cap passes shall be completed before the end of each day.

11.10.9 Weld sequencing shall be such that consecutive stop/start locations are staggered by a minimum of 50 mm.

11.10.10 Clusters of surface porosity, bead starts, heavy glass deposits and high points shall be removed by grinding before depositing weld metal over them. Cleaning shall be done by power or hand tools, or both, to the satisfaction of the Company.

11.10.11 Tie-in welds completed in the ditch shall be completed in a single work day.

11.11 Internal Backwelding

11.11.1 Should a mechanized production weld using an internal root weld process require back welding to correct for root weld misfires (not considered backweld repairs); only an approved and qualified low hydrogen shielded metal arc or semi-automatic welding WPS shall be used. For semi-automatic backwelds, qualified in accordance with the requirements of CSA Z662, Annex K, the defect acceptance criteria established by Annex K shall apply. For all SMAW low hydrogen manual back welds; the Company site inspector shall be notified and the entire circumference of the weld shall be inspected to the acceptance criteria as specified in section 7 of CSA Z662.

11.12 Weld Completion

11.12.1 The completed weld shall have a uniform cross section around the entire circumference of the pipe. At no point shall the top of the cap pass be below the surface of the pipe or


above the pipe surface by more than: 2.5 mm for pipe with nominal wall thickness 10 mm or less and 3.5 mm for pipe with nominal wall thickness greater than 10 mm. An additional 1.0 mm of weld reinforcement shall be permitted for localized areas at the discretion of the Company.

11.12.2 When files are used for cleaning up the final or cap pass, the metal thickness adjacent to the weld shall not be grooved below the minimum nominal pipe wall thickness. Should this occur the Contractor shall cut out the defective pipe by cutting out a ring of pipe containing the grooved pipe.

11.12.3 Welds that will be examined using AUT shall be cleaned to a standard sufficient to permit the AUT technique to be utilized. As a minimum this will include the cleaning of the weld and the removal of all weld spatter, slag and coating for a distance of 120 mm on both sides of the weld.

11.12.4 Each welder shall identify his Work by marking the pipe next to the weld with his unique identification number using an indelible permanent marking crayon.

11.12.5 In addition to their unique identification number, cap pass welders shall mark the weld completion date and time on the pipe next to the weld using an indelible permanent marking crayon.

11.12.6 The welded pipe shall be laid on skids after welding so that no portion of the pipe is allowed to touch the ground. The pipe shall be blocked and secured from rolling off skids in a manner acceptable to the Company. The spacing of skids shall be adequate to prevent undue stress on the free spanning pipe and on partly completed welds. Welds shall be left accessible for their full circumference.

11.12.7 Should a section of the pipeline fall off the skids, the Contractor shall immediately report this fact to the Company. The Company shall be allowed reasonable time to inspect the pipe section involved and the Contractor shall cut out and replace any defects and damaged pipe at the expense of the Contractor.

11.13 Night Capping

11.13.1 The open end of sections of pipe shall be securely closed at the end of each day's work by placing suitable covers over the ends to prevent the entrance of trash, animals or other obstructions, and these shall not be opened until Work at that location is to be resumed. Where the line is left open at intervals for pigging, testing or future tie-ins at roads, railroads, rivers, etc. both ends shall similarly be capped. Temporary nightcaps shall not be tack welded to the pipe. Garbage bags will not be accepted as nightcaps.

11.13.2 For mechanized welding, utilizing inert, active or a combination gas for shielding of the welding arc from the atmosphere, end caps shall be placed on the end of the start joint of all sections prior to welding, to prevent the removal of the gas shielding.

11.14 Arc Burns

11.14.1 Arcs shall be struck only in the weld groove. Arc burns shall be repaired/removed.

11.14.2 Arc burns may be repaired if they do not exceed 8% of the nominal pipe wall thickness in depth.

11.14.3 If arc burns exceed 8% of the nominal pipe wall thickness in depth, they shall be removed by cutting out a complete pup of pipe.


11.14.4 Authorization for the repair of arc burns will not be granted until the Contractor submits a detailed written Repair Procedure to the Company, and these Procedures have been approved by the Company. As a minimum, Repair Procedures shall address:

11.14.4.1 Method of surface preparation;

11.14.4.2 Required surface finish;

11.14.4.3 Type and concentration of etchant used;

11.14.4.4 Safety procedures for handling chemical reagents;

11.14.4.5 Method of etchant preparation;

11.14.4.6 Etchant application method and application time, which must address the effect of metal surface temperature if required to improve reaction time;

11.14.4.7 Periodic testing of the effectiveness of the etchant (i.e. frequency of testing and method of testing);

11.14.4.8 Equipment and procedures for ultrasonic thickness testing;

11.14.4.9 Qualifications of ultrasonic thickness testing personnel; and

11.14.4.10 Forms for recording the results of each arc burn evaluation, including space for identification of weld number; pipe number containing the arc burn, circumferential location of the arc burn, remaining wall thickness after removal of the arc burn, and the final result of the evaluation.

11.14.5 The written Arc Burn Repair Procedure shall be available at the work location. The Company reserves the right to witness removal of arc burns, and to perform any other checks or tests necessary to verify acceptability of the removal of arc burns.

11.15 Pipe Pups

11.15.1 The Contractor shall mark the pipe number and heat number on the outside and inside of all pups using a weather proof marker.

11.15.2 Pipe pups 2m for less than 508 mm OD, 3m for 508/609.6 mm OD and 4m for above 609.6 mm OD in length shall be moved ahead daily and welded into the line. Pipe pups less than 5 meters in length shall not be welded in sequence; they shall be separated by a full joint of pipe.

11.15.3 Pipe pups shall not be allowed to accumulate on the Construction Right-of-Way and a reasonable attempt shall be made to progressively weld all pipe pups into the line. The Company may stop the Contractor's mainline welding operation before completion of mainline welding so that accumulated pipe pups can be moved ahead and welded into the pipeline.

11.16 Welding Refuse

11.16.1 Welding consumable stubs, excess wire and clippings, weld consumable packaging, wire spools or other refuse produced by the welding operation shall be removed from the Right-of-Way immediately for appropriate disposal.


11.16.2 The Contractor shall ensure that refuse shall not be left inside the pipe after back-welding or any other internal operation completed by the Contractor

11.17 Weld Inspection and Acceptance

11.17.1 The Company shall have the uninhibited right to inspect and monitor all aspects of production welding to ensure the WPS and this specification are being followed, and shall have the unilateral right to reject any welds in which the details of the WPS are not followed, at no incremental cost or schedule impacts to the Company.

11.17.2 NDT of all completed butt welds shall follow the guidelines specified Table 6.

11.17.3 All NDT shall be performed in accordance with the current version of the company specification CPCS-SPEC-NDT-003 – Specification for Pipeline Construction (Canada) Non-Destructive Testing.

11.17.4 Visual inspection shall be performed on all welds and shall be assessed in accordance with the acceptance criteria as specified in section 7 of CSA Z662 or criteria defined in accordance with the requirements of Annex K as applicable. The Company has the right to reject any welds that in its opinion, although marginally satisfy the minimum code requirements, could be detrimental to the long-term integrity of the pipeline.


Table 6: NDT Requirement Guidelines

JOINT DESIGN

WELDING CREW

Mainline & Section SMAW

Mainline & Section

Mechanized GMAW

Tie-in Final Tie-in Weld-Repair

Equal Nominal Wall Thickness

100% circumference RT

or UT + 100% circumference

visual + 20% next day delay RT or UT

100% circumference UT

+ 100% circumference

visual



visual + 20% next day delay RT or

UT


or UT + 100% circumference visual + 100%

next day delay RT or UT

RT or UT + visual + 20% next day delay RT or UT

Unequal Nominal Wall Thickness

(within allowable 1.0mm difference)



visual + 100% next day delay RT or UT



visual




N/A RT or UT + visual + 100% next day delay RT or UT

Back-Bevel Transition



visual + 100% next day delay RT

N/A


+ 100% circumference visual + 100%

next day delay RT

N/A RT + visual +

100% next day delay RT

Counter Bore and Taper Transition



visual + 100% next day delay RT



visual



visual + 20% next day delay RT or

UT




RT or UT + visual + 20% next day

delay RT

NOTE(s) 1. Next day delay means a minimum of 18 hours from the completion of welding 2. Delay inspection can be either a first or subsequent inspection 3. Delay inspection time (hours) shall be documented by the company

11.17.5 All butt welds shall be inspected for 100% of their circumference using radiographic and/or ultrasonic techniques. Other welds may be inspected using visual and other NDT techniques. Defect acceptance criteria shall be based upon the defect acceptance criteria outlined in CSA Z662, "Standards of Acceptability" or as determined in accordance with Annex K of CSA Z662 and the additional requirements of this specification as follows:

11.17.5.1 All cracks or crack-like indications shall not be repaired and an entire weld cylinder shall be cut-out and obtained for investigation in accordance with the company Weld Crack Investigation Procedure CPCS-PROC-WCI-005

11.17.5.2 Internal undercut shall not exceed the lesser 10% of wall thickness or 2mm as measured through AUT dimensioning or RT contrast comparisons with undercut shims.

11.17.5.3 Copper inclusions shall be removed from the system by cutout of the entire weld.


11.17.5.4 When welds are completed using a mechanized process utilizing an external root process with internal copper backup, “burnthrough” flaws, where loss of weld or base metal backing could have caused the welding arc to have direct contact with the copper backup plates, shall be removed from the system by cutout of the entire weld. These flaws are characterized through AUT and/or RT as “cup shaped” indications in the transit distance of the root channel that is accompanied with a TOFD signature identified by a fading of TOFD backwall combined with an indication of short length earlier in the time of flight. To validate a burn-through flaw identified by AUT as above, the area shall be inspected using RT to confirm the burn-through. If a burn-through flaw is confirmed the entire weld shall be cut out and removed from the system.

11.17.6 All reasonable attempts will be made to provide non-destructive test results to the Contractor approximately one hour before the start of the next working day. The Contractor shall cooperate fully with the NDT crews carrying out the required tests.

11.17.7 All mainline welds and weld repairs shall be left uncoated for one full day beyond the day that the weld was completed on, to allow the Company time for any additional inspection. Tie-in welds may be required to remain uncoated for one full day beyond the day the weld was completed, at the discretion of the Company.

11.17.8 Welds that do not comply with the defect acceptance criteria of these Specifications shall be removed or repaired at the Company’s discretion.

11.17.9 All welds that fail testing as per the specifications shall be replaced by the Contractor.

11.17.10 The Company, at its option, may cut out all questionable welds or additional welds for production test purposes. The Company will, whenever possible, select test welds to be cut from the pipeline in a location that will minimize the replacement impact.

11.17.11 WPS established in accordance with ASME IX, shall use acceptance standards in accordance with the requirements of the ASME Code for Pressure Piping, B31.3, normal fluid service.

11.17.12 Weld conditions that prevent proper interpretation of radiographic or ultrasonic evaluations shall be cause for rejection of the welds affected, unless they can be inspected by other Company approved methods.

11.17.13 If the mechanized welding system used for welding uses an alignment band similar to that used for the mechanized ultrasonic evaluation, the alignment band shall be maintained and provided by the contractor and be left on the pipe until after the ultrasonic evaluation of the weld has been completed at no incremental cost to the Company.

12 WELD-REPAIRS

12.1 General

12.1.1 The Contractor shall be responsible for identifying and marking the location(s) of the weld-repair on the weld circumference that requires weld-repair.

12.1.2 Remedial Work on the cap pass may be completed before non-destructive testing, but only with prior approval from the Company, and then only in accordance with the requirements of an approved WPS.


12.1.3 The root pass of through wall weld-repair welds shall be completed using E6010 electrodes. The second pass may be welded with cellulose electrodes.

12.1.4 The fills and cap passes of weld-repair welds shall be made using low hydrogen welding processes except for materials with Grades up to 386 inclusive where cellulose consumables are permitted.

12.1.5 Back welding weld-repair welds shall be limited to root pass repairs only unless otherwise approved by the company and only low hydrogen welding processes and consumables shall be used.

12.1.6 Partial through wall weld-repair welds or weld-repair welds performed by back welding are allowed in any location on the entire circumference of the weld. The cumulative length of through-wall weld-repair welds shall not exceed 30% of the total length of the original weld

12.1.7 All cut-outs shall be returned to the Contractor’s yard and remain the property of the Company.

12.2 Weld-Repair and Removal of Defects

12.2.1 Any weld that does not meet the defect acceptance criteria of CSA Z662 or ECA defect acceptance criteria defined by the Company shall be repaired or removed. All weld-repair welding shall be performed in accordance with the approved weld-repair WPS.

12.2.2 The minimum length of any weld-repair weld shall be 50 mm.

12.2.3 The minimum preheat established in the approved WPS shall be applied before removing the defect by grinding. The minimum preheat temperature shall extend a minimum of 150 mm in any direction extending from the weld-repair and shall be maintained throughout the preparation and welding operation.

12.2.4 Weld-repairs shall be completed in a full operation without stopping.

12.2.5 Weld-repairs shall not be started if prevailing weather conditions or other conditions suggest that full completion of the weld-repair may be interrupted.

12.2.6 External weld-repairs exceeding the lesser of 25% of the pipe circumference or 300 mm in length shall be completed in multiple operations. The maximum length of root weld-repair completed in a single operation shall be the lesser of 25% of the pipe circumference or 300 mm. The root pass, second pass and one fill pass shall be completed before additional weld-repair length is attempted.

12.2.7 The Contractor shall be permitted one attempt for weld-repair welding of root defects unless a WPS has been specifically qualified for multiple weld-repairs in accordance with the requirements of this Specification and the WPS has been approved by the Company. A second attempt may be permitted for second pass, fill and cap weld-repairs if previously approved by the Company.

12.2.8 Oxygen cutting of weld defects is not permitted. Air arc gouging of weld defects may be permitted if the Contractor submits a written procedure for gouging that is subsequently approved by the Company. Grinding entirely through the weld thickness is only permitted if specified in the Company approved weld-repair WPS.


12.2.9 Welds that do not meet the minimum requirements of this Specification shall be cut out and replaced with a new weld. If pulling the pipe back into position after a weld has been removed is not possible a pipe pup shall be used. The minimum permissible length of replacement pipe shall be as follows:

12.2.9.1 150 mm, for pipe smaller than 168 mm OD;

12.2.9.2 Two times the specified outside diameter, for pipe from 168 mm to 610 mm OD; and

12.2.9.3 1.2 meters for pipe larger than 610 mm OD.

12.3 Inspection of Weld-Repairs

12.3.1 Weld-repairs may be inspected using any method of NDT that in the opinion of the Company would best determine the acceptability of the weld. The non-destructive test method used originally to identify the defect must also be used in the assessment of acceptability of the weld-repair area.


13 APPENDICES • Appendix A - Mechanized WDS Template

• Appendix B - SMAW WDS Template

• Appendix C - Project WPS Matrix (Pipeline)


Appendix A

Mechanized WDS Template


Appendix B

SMAW WDS Template


Appendix C

Project WPS Matrix (Pipeline)

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