Chapter 11 of EPI Part 10 Construction Specification 11. WELDING. a) Scope

Transcription

1 Chapter 11 of EPI Part 10 Construction Specification 11. WELDING a) Scope These welding Specifications for Mainline Construction detail the requirements for mainline welding, repair welding, tie-in welding and fabrication welding of pipe and welded components for oil pipeline systems. All welding shall be in accordance with CSA Z662-07, the NEB Pipeline Regulations and these Specifications. Should a conflict arise between these documents the Company specification shall prevail. General These specifications cover the requirements for: Bevel Preparation Equipment Materials Welding Procedure Qualification Welding Consumables Welder Qualification Production Welding Welding Performance Requirement Preparation of Pipe Alignment and Fit up Preheat and Interpass Temperature Welding Sequence Manual Welding Mechanized Welding Weld Inspection and Acceptance Repairs The Contractor shall supply all labour, equipment and materials, except materials specified to be supplied by the Company, and shall perform all welding necessary to produce a pipeline in accordance with the Contract.

2 Definitions The Company shall supply pipe and other welded components for the Work in specific sizes and grades listed in the Description of Work. When welding of higher grade pipe materials i.e. Grade 550 or greater is required, the Company shall have final approval regarding essential variables or changes prior to welding procedure development or qualification. Welding shall be done by 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. Fabrication welding may also use the submerged arc welding process. The Company will provide the Contractor pre-qualified welding procedures all pipe grades and diameters specified for the project. Pre-qualified welding procedures will be provided for mainline, tie-ins, repair and fabrication welding. The Contractor may propose their own existing procedures for approval by the Company. Proposed existing procedures shall be provided to the Company for approval a minimum of 60 days prior to start of welder qualification. The requirements of the welding procedure specification are detailed within this specification. No welding shall be done unless the appropriate company approved welding specification is on site. Welding Procedure Specifications and welder qualifications shall be in accordance with the requirements of CSA Z662-07, the NEB regulations and these Specifications. The Contractor shall designate a suitably qualified individual to monitor and document welding essential variables and shall provide this documentation to the Inspector on a daily basis. Enbridge 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. Contractor shall provide the Senior Welding Inspector with a daily report showing the documentations completed. 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 Welding Data Sheet (WDS). Welding terms and definitions shall be in accordance with CSA Z and these Specifications. Arc Strikes - Localized areas where an electrical arc has heated an area away from the weld joint bevel and weld heat-affected zones (HAZ). 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 welding procedure specification suitable for the materials to be joined. Bridge tacks shall only be applied to the prepared bevel end. CConsistency Test - A series of at least three (3) consecutive defect free test welds intended to prove a welder has developed sufficient skills when operating a mechanized or semiautomatic welding system and process. Each weld shall be non-destructively examined for defects to the workmanship acceptance criteria using mechanized ultrasonic or radiographic inspection and visual inspection.

3 Controlled Cooling - A method of controlling the cooling rate of a welded joint. Controlled Welding Section - A section of welds consisting of a defined number of welds that show the Contractor's ability to establish and maintain a consistent workmanship standard as defined by the Company. Counterbore 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 Variable A welding variable that may affect the mechanical properties of the weld. Essential Changes are welding variables that have been altered outside the ranges specified in CSA Z662-07, Table 7.3 of clause or clause K.3.2. Fabrication Facility - A temporary or permanent location intended for construction of piping assemblies or equipment. Piping Assembly - A group of pipe or components, or both, joined by one or more circumferential welds. Witness Point - A milestone during the fabrication work, where the Contractor must notify the Company to facilitate his attendance prior to proceeding with any further sequences in the fabrication. Attendance at this point will be left up to the discretion of the Company. Hold Point - A mandatory notification point, whereby the Contractor must notify the Company and the Company must be in attendance prior to proceeding with any further sequences in fabrication. Inclement Weather - Weather conditions that prevent the Contractor from operating safely and/or in compliance with these Specifications. For further direction regarding inclement weather refer to the General Conditions. Interpass Temperature - The temperature of the weldment between weld passes, measured 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 repair weld. Latent Defects - Welding defects that take time to initiate and propagate, e.g., hydrogen cold cracks. Mechanized Welding - A welding method where the welding arc is moved along the weld joint by mechanical means. Procedure Compliance - Compliance to all welding essential variables as defined by this Specification and CSA Z Procedure Qualification Record - (PQR) Procedure Qualification Records are the actual documented variables recorded during the qualification welding of test coupons to show the compatibility of consumables and techniques in the joining of materials typical for a given welding procedure specification. It also contains the mechanical test results of the tested specimens. Production Welding - Production welding shall include all the welding completed in the performance of the Work including mainline welding, tie-in welding, repair welding and fabrication welding.

4 Repair rate - The percentage of welds that require repair, calculated by dividing the total number of welds that require repair over a given period of time by the total number of welds produced during that same period of time. 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. Final Tie-in - A weld completed in the trench that joins completed sections of the pipeline without a "free end" or a weld which will not be included in a hydro test prior to the pipeline system being placed into service. Welding Data Sheet - (WDS) A single page summary of the Welding Procedure Specification intended as quick reference for the welders and Inspectors to ensure familiarization of all the essential changes for welding. It is intended that all welders receive a copy of each data sheet that applies to their particular application to ensure they are aware of what practices must be followed. Welding Preheat - Application of heat applied to a weldment prior to welding to ensure adequately slow cooling conditions. Preheat is measured at a location with a maximum distance of 50-mm from each side of a production weld or 150 mm in any direction from the edge of a repair area. Welding Procedure Specification - (WPS) The WPS takes the essential variables recorded during the development of the PQR and extends these into a range of essential variables to be followed for a specific task. Guidelines are given for the application of the welding, i.e., preheats, consumables, heat inputs. Welding Procedure - A collection of the WPS, PQR and all mechanical test reports. Welding Specification A detailed document prescribing guidelines and mandatory requirements when welding of pipe and components. Weld Classification i) Groove Welds The Company shall approve bevel preparations before qualification of welding procedures. For pipes and components NPS 2 and larger, where practical, welded joints shall be made with single or double groove butt joints. ii) Fillet Welds Fillet welds shall be concave to slightly convex. 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 for 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.

5 Welded outlets shall be attached using fillet reinforced groove welds. Low hydrogen welding processes shall be used, except the first weld pass (root) may be welded using cellulose electrodes. All subsequent weld passes shall be completed using a low hydrogen welding process and consumables. A minimum of two weld layers is mandatory. Where approved by the Company, the second pass (hot pass) may also be welded using cellulose electrodes. iii) Tack Welds Tack welds shall be done by qualified welders and shall be preheated in accordance with the requirements of the Company approved qualified Welding Procedure Specifications to be used for the completed weld. Tack welds: Shall be of a sufficient number, size and quality, to maintain alignment and minimize the risk of breaking or otherwise compromising safety. Shall only be permitted in the weld bevel area. 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 weld procedure. 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. Root tacks may be used for piping assemblies smaller than NPS 16. Sound root tacks made according to a Company approved welding procedure for the joint may be incorporated in the final weld, provided complete penetration and fusion is obtained in the completed root bead. Root bead segments deposited using external line up clamps, in accordance with a Company approved welding procedure, are not considered to be tack welds. Bevel Preparation Final bevel preparation shall be as shown on the Company approved welding procedure specification. The Contractor shall prepare bevels using machine tools, or automatic or semi-automatic oxy-fuel gas cutting equipment, so that the finished ends are square within 1.6 mm (1/16"). Free-hand manual oxygen cutting is not permitted. Burns, small scores, indentations or other defects within the joint preparation area shall be removed by 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 reprepared. For mechanized narrow gap welding, bevel dimensions shall be as specified in the Company approved welding procedure specification. Defects found within the precision machined bevel area, i.e. unfinished machining, gouges and dents that may affect the quality of the finished weld product shall be brought to the attention of the site inspection personnel. If these bevel defects can not removed by light filing or grinding, re-machining of the bevel shall be completed.

6 Weld repair of bevels shall not be permitted. 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 welding procedure. Laminations or split ends removed from piping components shall be provided to the Company for disposition. Bevel dimensions shall remain as specified on the Company approved welding specification. The Contractor shall supply a suitably trained individual to monitor and document bevel dimensions, based on the dimensions provided within the 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. Alignment of abutting ends shall be such as to 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 equally around the circumference of the joint. For mechanized welds inspected with automated ultrasonic testing (AUT), the maximum abutting surface offset shall be 1 mm. If the difference in nominal wall thickness of adjoining pipes exceeds 1.6 mm, transitioning of the thicker pipe down to the thinner pipe shall be required. The design of such transitioning shall be such to accommodate the welding technique and the non-destructive examination technique, without any additional set-up or delays. The Contractor shall note that a counterbore and taper design is the required transition design for all welds inspected using an ultrasonic inspection technique. For final tie-ins, 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. When back bevel tapered transitions are permitted, radiographic weld inspection testing techniques are required. Final radiographic inspection shall not be completed until a minimum of 24 hours after the completion of the weld. 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. The Contractor is responsible for preparing all transitions and transition pieces. Where factory pipe ends have been removed, the submerged arc welded (SAW) longitudinal and spiral seam welds shall be ground smooth (+0.5 mm, -0 mm) and the coating shall be removed for a distance of mm from the edge of the bevel. If the joint bevel is intended for mechanized welding or AUT, the seam weld and pipe coating shall be removed and ground smooth, both internally and externally, for a distance of 100 mm from the edge of the bevel. The use of wedges to correct minor out-of-roundness and hi-low shall not be permitted unless approved by the Company. All seams shall be offset by 50 mm to ensure that the seam of the pipe does not line up with the seam of the adjacent pipe or component. All branch type attachments shall be located at least 50 mm from circumferential or longitudinal seam welds unless otherwise approved by the Company.

7 Equipment Pipe supports shall be used to minimize stress and sag in the assemblies. The practice of tack welding supports, bracing bars or counter balance weights onto the fabricated assemblies is not permitted. During pipe end preparation work, all waste metal shall be gathered and removed from the Construction Right-of-Way at the end of each day 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. The Company may require an alternative magnetic pick up procedure if the tarpaulin collection method is found by the Company to be unsuccessful. The Contractor shall supply all necessary equipment required for the satisfactory completion of the Work, and the equipment shall be maintained in such condition as to provide continuity of operation, and safety of personnel. Any equipment or supplies not satisfactory to the Company shall be replaced to the satisfaction of the Company at no additional compensation to the Contractor. 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 at no expense to the Company. For mechanized welding applications, welding equipment utilized for production welding shall be the same type and model used for welding procedure qualification. Pre-production welds should be performed qualifying any and all equipment to be utilized for production welding. Welding procedure specification compliance remains the responsibility of the Contractor. Even though the welding procedure specification has been approved by the Company, the Contractor remains responsible for the technical performance of the qualified welding procedure specification and remains responsible for providing welds which are sound and suitable for the intended service qualified. When software driven, digitally controlled welding power sources and Contractor proprietary digital interface are utilized for welding procedure 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 welding procedure qualification and also during production welding. If the Automated Ultrasonic Test (AUT) system 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 to the AUT contractor so not to impede daily AUT inspection work progress. Arc welding equipment shall be operated within the amperage, voltage, travel speed and heat input ranges specified in the Company approved Welding Procedure Specifications. Suitable means of measuring welding amperage, voltage and travel speed shall be available to monitor compliance with the qualified Welding Procedure Specifications. Line-up clamps shall be designed to avoid mechanical damage to the piping and to maintain alignment within specified tolerances. For mechanized welding applications, a comprehensive list of spare parts and/or mechanized welding equipment shall be provided to the Company before the start of production welding.

8 Sufficient spare parts and/or equipment shall be provided and maintained by the Contractor to ensure consistent weld quality and continuity of construction. For external mechanized mainline welding, welding shelters shall be provided for each welding station to provide protection from inclement weather. Shelters shall provide protection from inclement weather, adequate lighting, electricity, ventilation and flooring to give a safe working environment, with sufficient space for a welder and helper on each side of the pipe. One door shall be provided to access each side of the pipe. 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 welding procedure qualification should be consistent with field welding applications. The Contractor shall ensure that any proprietary weld metal transfer waveform technology, e.g. GMAW pulse transfer, is maintained as per procedure qualification records. When automated welding controls are enabled during procedure qualification, the Contractor shall ensure that similar automation control is maintained for all production welding. If the auto work piece to contact tip height adjust and/or girth weld bevel tracking automation is not used during procedure qualification, it may be used during production welding without additional qualification. 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. Materials i) General The Contractor shall supply all consumables required for the satisfactory completion of the work. Only new filler metals and shielding gases having prior approval from the Company shall be used. The Contractor shall make all efforts to ensure that welding consumables from previous projects are removed from welding rigs prior to the commencement of work on Company projects. ii) Consumables 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. The Contractor should 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 shall be stored and handled to avoid damage to them and to the containers in which they are shipped. 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 cause rejection of the entire box or container. As well, all welds welded using suspect electrodes will be cut out and replaced at the Contractor's expense.

9 Storage, exposure periods and reconditioning of electrodes shall be in accordance with manufacturer s recommendations. The Company reserves the right to prohibit the use of materials that it deems unsuitable for proper performance of the work. iii) Shielding Gases Shielding gases shall be approved by the Company. 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 34 o C or lower. Certificates attaining to this shall be provided by the Contractor. 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. Gas flow regulators for the appropriate shielding gas shall be used and shall be kept in good working condition such that the correct shielding gas flow rate is as required by the approved welding procedure specification. iv) Welding Consumables Internal back-welding repair welds shall be completed with low hydrogen consumables in accordance with Company approved procedures. Low hydrogen shielded metal arc welding electrodes, when removed from sealed containers, shall be stored in cabinets at temperatures in the 120 o 150 o C 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 the applicable manufacturer's recommendations. 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 be discarded, and then replaced at the Contractors expense. Any production welds completed with damaged or unsuitable consumables shall be removed and replaced from the construction system at the Contractors expense. Production welds shall be completed using the same brand name and AWS/ASME filler metal and flux classifications as used during procedure qualification. If changes to filler metal or flux brand name or AWS/ASME classification are necessary, complete re-qualification of the welding procedure with the new filler metal and/or flux is required. The Company shall be informed of any changes of electrode brand names from that used for procedure qualifications. The Company reserves the right to require re-qualification of a welding procedure on the basis of electrode brand name changes. For submerged arc welding, all fluxes and electrodes shall be approved by the Company. The Contractor shall state within the intended welding procedure specification; the flux method of manufacture, the flux activeness and classification for approval by the Company. All fabrication welds including butt welds, fillet welds, 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:

10 a) The root pass and hot pass of butt welds; b) The root pass and hot pass of through wall weld repairs; c) All passes of butt welds joining pipe to pipe; and d) All passes of pipe to component, and component to component welds where: v) Pipe and Components i) Base metals are plain carbon ASTM P-No. 1 steels with SMYS less than 386 MPa; ii) Electrode SMTS is less than or equal to 480 MPa; and system pressure rating is PN 50 or lower. 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 back-welding procedures to be implemented. This is not an abnormal condition, particularly on heavy wall thickness material. Qualification of Welding Procedure Specifications i) General For weld procedure qualification purposes, welding operations have been classified as follows: mainline welding mainline and tie-in repair welding, including back welding tie-in welding site and shop fabrication welding, and site and shop fabrication repair welding During the qualification of Welding Procedure Specifications (WPS), production welding shall be simulated as closely as practical including the effects of ambient conditions and pipe stresses. Processes, bevel design and alignment, consumables and welders used for weld procedure qualifications shall be approved by the Company, and shall be in accordance with CSA Z662, these specifications and referenced documents. Procedure qualification essential variables shall be as defined by CSA Z662 and these specifications. In addition to the requirements specified in CSA Z662 the following essential variables shall be applied during welding procedure qualifications.

11 (1) Electrode Qualification Requirements* Table 11.1 Welding Procedure Specification Restrictions Maingang Poorboy Section Tie-ins Repairs Throughwall Backweld Repairs SMAW ROOT PASS E6010 E6010 SMAW HOT PASS EXX10-G or P1** EXX10-G or P1** SMAW FILL/CAP PASS EXX10-G or P1** E8018-C3 E8018-C3 N/A N/A MECHANIZED GMAW ALL PASSES As Determined by Company N/A As Determined by Company NOTE: *Shield metal arc welding consumable tensile strength levels shall be specified by the Company for pipe base materials greater than 483 MPa. **Tensile strength levels for cellulose consumables shall be determined by the pipe material UTS. Grade 550 pipe shall be welded using E9010-G electrodes except that fill/cap pass of repair welds shall be welded using E8018-C2 electrodes. (2) Maximum Travel Speed SMAW WELD PASS ROOT PASS Maximum Travel Speed 457 mm/min (18 inches/min) (3) Interpass Temperature WT mm (in.) Under 4.78 (under 0.188) 4.78 to 9.53 ( ) 9.54 to ( ) 12.7 to 19.1 ( ) mm ( in) 100 F (38 C) 100 F (38 C) 100 F (38 C) 150 F (66 C) Minimum Interpass Temperature for Production Welding O.D mm mm 219.1mm ( in) ( in) ( in) 100 F (38 C) 100 F (38 C) 150 F (66 C) 200 F (93 C) 100 F (38 C) 150 F (66 C) 200 F (93 C) 250 F (121 C) 150 F (66 C) 200 F (93 C) 250 F (121 C) 250 F (121 C) Over 406.4mm (Over in) 200 F (93 C) 250 F (121 C) 250 F (121 C) 250 F (121 C) NOTE: (1) Consideration shall be given by the Company to lower interpass temperature values if the root pass is deposited with a low hydrogen welding consumable or process. Mechanized GMAW techniques shall be qualified using a minimum interpass temperature of 50 ºC. (2) Fabrication welding shall have a minimum interpass temperature of 150 C for all piping wall thicknesses greater than 12.7 mm.

12 Pipe O.D. Figure 1A: Repair Weld Procedure Qualification Test Assembly Figure 1B: Through Wall Repair Procedure Qualification Coupon (Represents One Quadrant)

13 Figure 1C: Backweld Repair Procedure Qualification Coupon (Represents One Quadrant) (4) Maximum Time Interval Between Weld Passes TIME INTERVAL 10 MINUTES MAXIMUM ROOT PASS TO HOT PASS 60 MINUTES MAXIMUM HOT PASS TO FILL PASS 24 HOURS MAXIMUM FILL PASS TO CAP PASS NOTE: (1) All fill passes shall be completed prior to the weld being left for maximum 24 hours. (2) Consideration shall be given by the Company to longer time intervals between the root pass to hot pass provided the root pass is deposited with a low hydrogen consumable, and the extended time interval was qualified during welding procedure qualification. (3) Time interval between the fill pass to the cap pass (i.e. to completion) may be extended with approval of the Company.

14 The Contractor shall be responsible for the performance and quality of all welding, in accordance with the welding procedures developed for the work or pre-qualified welding procedures accepted by the Company. The Contractor shall signify his acceptance of this responsibility by signing a Welding Data Sheet for each welding procedure to be used on the project. ii) Mainline Weld Procedure Qualification During welding procedure qualification, field weld interpass temperature cycles shall be simulated as closely as possible. At the completion of the hot 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. As a part of the mechanized welding procedure 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. iii) Mainline Manual SMAW Repair Weld Procedure Qualification The repair weld procedure shall consist of: A simulated through wall repair of a girth weld; and A simulated back-weld repair of a girth weld. Only Company approved back weld procedures shall be allowed qualification. Only low hydrogen welding consumables shall be allowed for back welding. SMAW and GMAW back weld procedures shall be inspected to workmanship criteria. The essential changes utilized in the qualified mechanized welding procedure shall match the semi-automatic welding procedures. A drawing of the test assembly is shown in Figures 1A, and a schematic of the test preparation and sampling locations for each repair quadrant are shown in Figures 1B and 1C. Repair welds shall be completed as follows: a) Q1 and Q3 shall be a through wall repair simulation, where the root and hot pass are deposited in the downhill direction using cellulose electrodes. Fill and cap passes shall be completed in the uphill direction with low hydrogen electrodes. b) Q2 and Q4 shall be a back-weld repair over a root bead excavation approximately 1.5 mm deep and 150 mm long, using low hydrogen electrodes. Weld repair procedures shall be completed using 120 C minimum preheat, and interpass temperature. All repairs shall be made using a low hydrogen process; except for through wall repairs where the root pass shall be completed using E6010 electrodes and the second (hot) pass may be welded with cellulose electrodes. Each through-wall repair weld shall be non-destructively tested by radiographic and/or ultrasonic testing and magnetic particle methods after the weld has cooled to ambient temperature and before being destructively tested. Two tensile tests, two nick break tests, two root bends, two face bends, weld metal impact tests, H.A.Z. impact tests, and a hardness survey shall be carried out on samples removed according to Figure 1B.

15 Back weld repair qualifications shall be mechanically tested by completing a hardness survey as described in the previous clause. iv) Tie-in Manual SMAW Procedure Qualification If mainline welding procedures are deemed unsuitable for tie-in welding, then tie-in welding procedures will be developed and qualified. v) Fabrication Weld Procedure Qualification Fabrication welding shall have a minimum interpass temperature of 150 C for all piping wall thicknesses greater than 12.7 mm. Welding processes used for fabrication welds are restricted to SMAW, GMAW, FCAW, and SAW. Fabrication welding procedures shall be qualified according to these Specifications and: CSA Z662, or ASME IX with CSA Z662, compliance Fabrication weld procedure qualification tests shall include full radiographic examination, impact testing of weld material and HAZ's and cross-section hardness surveys for each procedure qualification test. vi) Fabrication Repair Weld Procedure Qualification If the Contractor proposes a fabrication repair weld procedure that is different from that qualified for use on mainline and tie-in welds, the Contractor shall qualify the proposed fabrication repair weld procedure in the same manner as shown for mainline and tie-in repair weld procedures. Minimum preheat and interpass temperature for fabrication repair weld procedures shall be 120 o C except as specified in Note 2 Table 11.1 (3). vii) Non-destructive Testing of Weld Procedure Qualification Test Coupons Immediately after welding, each procedure qualification test coupon shall be visually examined and fully radiographed. Acceptance criteria shall be as stated in CSA Z Section All SMAW weld procedure qualification test coupons shall be left for at least 24 hours (48 hours preferred). After this time period: a) Each weld procedure qualification test coupon shall be completely re-evaluated using radiographic techniques. b) Each root bead shall be examined for evidence of cracking by the magnetic particle method, using wet fluorescent or black and white colour contrast indicating mediums. viii) Destructive Testing of Weld Procedure Qualification Test Coupons Following successful completion of non-destructive examinations, weld procedure test coupons shall be destructively tested according to the requirements of CSA Z662, or ASME IX as applicable, and the following requirements.

16 Radiography shall not be used to define sound areas of the weld for destructive testing. Impact tests shall be conducted on the weld metal and heat affected zones of each weld procedure 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 Z Charpy impact tests shall be conducted according to ASME Section VIII, Division 1, Paragraph UG-84, using samples obtained from approximately the three o'clock position. Impact test reports shall include absorbed energy, shear area, and lateral expansion. 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. A cross-sectional hardness survey shall be made one (1) mm below each of the inside diameter and the outside diameter surfaces using a Vickers Diamond Pyramid Indenter with a ten (10) kg load. The survey shall be taken across the weld metal, both coarse grained heat affected zones and parent metal on both sides of the weld. H.A.Z. 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. For mechanized welding processes, 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. The facility chosen by the Contractor for mechanical testing shall be approved by the Company prior to its use. The completed procedure qualification weld shall also meet the radiographic defect acceptance criteria in accordance with the requirements of CSA Z662. Non-destructive techniques shall be similar to those to be used for inspection of production welding. i) j) Welder Qualification (i) General Each welder employed by the Contractor to work on the pipeline system shall be skilled and qualified for the type and methods of welding he or she will do, in accordance with CSA Z662-07, and these Specifications. Welders qualifying for fabrication welding may meet the requirements of ASME Section IX Boiler and Pressure Vessel Code or CSA Z

17 The Contractor shall use only skilled and qualified welders. Welders shall qualify by demonstrating their ability to produce acceptable welds in accordance with the Company approved Welding Procedure Specifications for the particular welding configuration or application to be used in production welding. No welder shall carry out any phase or type of welding for which he has not been tested and accepted by the Company as qualified. Welders failing to meet the minimum requirements of this Specification shall not be permitted to retest for a period of thirty days. Welders intended for use at tie-ins shall also be qualified for repair welding. Welders that have not qualified for repair welding shall not be permitted to weld tie-in welds. No welder qualification shall be permitted on field production welds unless otherwise approved by the Company. (ii) Test Requirements For mechanized welding systems that use external root pass techniques, the welder shall qualify by welding all weld passes. For mechanized welding systems that use internal root pass techniques, the welder shall qualify by welding all external weld passes. For mechanized welding with an internal line up clamp, operators/welders placed operating this 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. Pipe material used for welder qualification testing will be provided by the Company. Welder qualification testing shall be completed using internal line-up clamps. The line-up clamp shall not be removed until after the completion of the hot pass. For the purpose of welder qualification testing with an outside diameter greater than mm (12.750"), the terminology weld shall mean one half of the total pipe circumference and pipe with an outside diameter mm (12.750") or less, the terminology weld shall mean the entire pipe circumference. 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. For mainline welding process/techniques other than conventional manual cellulose SMAW, consistency shall be based upon, and qualification shall be dependant upon, the welder 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 used for qualification purposes. For conventional manual SMAW, consistency shall be based upon, and qualification shall be dependent upon, the welder completing one acceptable test weld. Test welds shall be produced in accordance with the Company approved Welding Procedure Specifications, by each welder, and shall be radiographically and/or ultrasonically inspected using techniques similar to those to be used for inspection of production welding.

18 Welders performing repairs shall be qualified in accordance with the approved full through wall repair welding procedure. This test shall qualify them for partial through wall repairs. A separate qualification shall be performed for back-weld repairs. The full through wall repair welding test shall consist of simulating two full-through-wall 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 repair section shall 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 welding procedure. The back-weld repair welding test shall consist of simulating two back-weld repairs on a previously completed test weld, with the pipe in the horizontal-fixed position. Two sections, one located approximately at the 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 repair section shall be approximately that of the original root pass. The length of each repair segment is dependent on pipe outside diameter as shown in the following table. Pipe Outside Diameter OD Minimum Length of Repair Segments Greater Than mm (12.750") 150 mm (6") mm (12.750") or Less 100 mm (4") Note: Small diameter pipes may require the use of more than one test weld to complete the two segments. Repair welders shall be evaluated according to the visual and radiographic requirements of CSA Z662, or the destructive testing requirements of the Company. Each welder and welding operator shall be qualified by visual and radiographic testing as permitted by CSA Z662. Acceptance criteria shall be as stated in CSA Z662. Each weld procedure 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. All test welds shall be witnessed by the Company and failure to comply with the Welding Procedure Specifications shall be cause for rejection. The Contractor shall prepare and maintain a list of welders, their qualifications in accordance to which welding procedure specification tested, and the date of qualification, which shall be updated after any change of welding personnel and submitted to the Company. 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.

19 If, in the opinion of the Company, failure of a welder to pass a test was because of unavoidable conditions or conditions beyond his control, such a welder may be given a second opportunity to qualify. No further retest shall be given. A welder may be required to re-qualify at any time if there is any reasonable doubt about the ability to produce acceptable welds. For mechanized welding, welders who have already qualified for the project and have not welded for a period of 90 days from their last production or qualification weld, shall be required 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. The Contractor shall notify the Company at least 24 hours prior to carrying out welder qualification tests to allow the Company to witness the welding and subsequent testing and arrange for an NDT unit to be available. j) Production Welding (i) General The welding of piping in accordance with this Specification shall be performed using qualified welders in accordance with the Company approved qualified Welding Procedure Specifications. Production welding shall not be performed when conditions encountered exceed the limits stated in the procedure specification. Subsequent to initial NDT inspection and at the Company s discretion, production welds may be held for an additional 24 hours for post weld inspection. To facilitate non-destructive testing 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. (ii) Contractor Documentation of Compliance 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 documentations shall be completed by the Contractor. Mechanized Welding FRONT-END (Pipegang): Two (2) welds, from each weld take one (1)-root pass parameter set plus one (1)-hot pass parameter set. BACK-END (Firing Line): Two (2) welds, from each weld take one (1)-fill pass parameter set plus one (1)-cap pass parameter set. Note: Parameter set shall include a random selection of amperage, voltage, travel speed and heat input. On back-end rotate through all weld passes over a short period (4-5 days). Identify all parameter locations by AUT weld number. Other data may be documented including but not limited to wire heat number, preheat/interpass temperature, gas types and flow rates, etc.

20 Repair Welding One (1) weld, random selection of amperage, voltage, travel speed (if possible) and heat input. Identify all parameter locations by AUT number. Other data may be documented including but not limited to electrode classification handling and storage. Tie-In Welding One (1) weld, random selection of amperage, voltage, travel speed and heat input for any two weld passes. Rotate through all weld passes over a short period (4-5 days). Identify all parameter locations by AUT number. Other data may be documented including but not limited to preheat/interpass temperature, electrode classification etc. 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. Contractor shall provide the Senior Welding Inspector with a daily report showing the documentations completed. (iii) Removal of Line-up Clamps When manual welding, internal line-up clamps shall not be removed until the second pass has been made across the bottom of the weld for the minimum length indicated in the following table. Pipe Outside Diameter OD Minimum Length of Second Pass 610 mm and Greater 250 mm Less Than 610 mm 150 mm The hot pass shall follow the root bead as closely as possible. For manual welding processes, not more than ten (10) minutes shall be permitted between completion of the root bead and start of a hot pass. Consideration by the Company may be given to extend this period of time for processes/techniques using low hydrogen consumables. Under no circumstances shall the minimum temperature be below the minimum interpass temperature until after the completion of the hot pass. Reheating is permitted before the start of the fill/cap pass. (iv) Internal Backwelding Should a mechanized production weld require back welding; only an approved and qualified low hydrogen shield metal arc or semi-automatic welding procedure shall be used. For semiautomatic 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 workmanship standards as specified in CSA Z662. (v) Welding Performance Requirements 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