s 000-1670-0006 v-3_general requirements for field & shop fabrication of piping

NSRP Complex Project

Nghi Son, Vietnam

Nghi Son Refinery and Petrochemical

Limited Liability Company

Employer Doc. No.

Contractor Doc. No.

S-000-1670-0006V

Rev. 3 of 53

Employer Contract No.: , Contractor JOB Code: 0-6495-20 Date: 21/Oct/14

Rev Date Page Description Prep'd Chk'd App'd

3 21/Oct/14 3 and 53 Addition of Licensor-2(CLG Requirement) S.O H.I/Y.S T.H 2 03/Sep/14 All S.O H.I/Y.S T.H

1 31/JUL/14 Cover Page Follow Employer comment on document title J.Y.Kim H.I T.H

0 27/JUN/14 All Issue for Construction J.Y.Kim H.I T.H A 29/NOV/13 All First issue S.O H.I/Y.S Y.O

Operation Centre JOB Code: Operation Centre Doc. No.:

Responsible Company JVD

Prepared by S. Ogida

Checked by H. Ishiga/Y. Sasaki

Approved by T.Hayashi

General Requirements for Field and Shop Fabrication

of Piping

Unit No.:000

Unit Abbreviation.: Not Applicable

Document Class: X

Issue Purpose For Construction

INDRA15-DEC-2014

NSRP Complex Project Employer Doc. No.

Rev. 3

Title: General Requirements for Field and Shop Fabrication of Piping.

Contractor Doc. No.

S-000-1670-0006V of 53

CONTENTS

1 SCOPE .................................................................................................................................................. 4

2 CODES AND STANDARDS ................................................................................................................. 4

3 MATERIALS AND PIPING CLASSES .................................................................................................. 5

4 WELD DESIGN ..................................................................................................................................... 5

4.1 Butt Welds ............................................................................................................................................ 5

4.2 Branch Welds ....................................................................................................................................... 5

4.3 Welded Pipe Bends ............................................................................................................................. 6

4.4 Proximity of Welds .............................................................................................................................. 6

4.5 Flanges ................................................................................................................................................. 6

4.6 Dimensional Tolerances ..................................................................................................................... 6

5 CUTTING AND WELD PREPARATION ............................................................................................... 7

5.1 Cutting Methods .................................................................................................................................. 7

5.2 Preheat for Thermal Cutting ............................................................................................................... 7

5.3 Dressing after Thermal Cutting .......................................................................................................... 7

5.4 Cleaning Prior to Welding ................................................................................................................... 7

6 PIPE BENDING ..................................................................................................................................... 8

6.1 General ................................................................................................................................................. 8

6.2 Carbon and Low Alloy Steels ............................................................................................................. 8

6.3 Stainless Steels ................................................................................................................................... 8

6.4 Bending Procedures ............................................................................................................................ 9

6.5 Standard of Finish ............................................................................................................................... 9

7 FIT-UP AND TEMPORARY ATTACHMENTS ...................................................................................... 9

7.1 General ................................................................................................................................................. 9

7.2 Removal of Fit-Up Welds .................................................................................................................... 9

8 WELDING .............................................................................................................................................. 9

8.1 General ................................................................................................................................................. 9

8.2 Welding Processes ............................................................................................................................ 10

8.3 Joint Details ....................................................................................................................................... 11

8.4 Welding Consumables ...................................................................................................................... 12

9 POST WELD HEAT TREATMENT (PWHT) ....................................................................................... 13

9.1 PWHT Requirements ......................................................................................................................... 13

9.2 PWHT Procedures ............................................................................................................................. 14

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9.3 Proximity of Welds ............................................................................................................................ 14

10 WELDING PROCEDURE QUALIFICATION ...................................................................................... 14

10.1 Welding Procedure Requirements ................................................................................................... 14

10.2 PQR Testing Requirements .............................................................................................................. 15

11 NON DESTRUCTIVE EXAMINATION (NDE) AND TESTING ........................................................... 16

11.1 Examination Class ............................................................................................................................. 16

11.2 Extent of NDE ..................................................................................................................................... 16

11.3 Timing of NDE .................................................................................................................................... 16

11.4 Radiographic Examination ............................................................................................................... 17

11.5 Production Hardness Testing .......................................................................................................... 17

11.6 Pressure Testing ................................................................................................................................ 18

11.7 Ferrite Content of Austenitic stainless Steel Welds ...................................................................... 18

11.8 Positive Material Identification (PMI) ............................................................................................... 19

11.9 Magnetic Particle Examination ......................................................................................................... 19

12 REPAIRS ............................................................................................................................................. 19

12.1 General ............................................................................................................................................... 19

12.2 Inspection ........................................................................................................................................... 19

13 RECORDS ........................................................................................................................................... 20

14 TABLE 1. WELDING CONSUMABLES FOR SPECIFIC MATERIALS ............................................. 21

15 TABLE 2. WELDING CONSUMABLES FOR DISSIMILAR METALS ............................................... 22

16 TABLE 3. PREHEAT FOR CARBON AND LOW ALLOY STEELS .................................................. 23

17 TABLE 4. HYDROGEN DIFFUSION HEAT TREATMENT FOR LOW ALLOY STEELS .................. 24

18 TABLE 5-1. PWHT OF CARBON AND LOW ALLOY STEELS ........................................................ 24

19 TABLE 6. POST BENDING HEAT TREATMENT FOR CARBON STEELS ..................................... 25

20 TABLE 7. EXAMINATION CLASSES ................................................................................................ 26

21 TABLE 8. EXTENT OF EXAMINATION (NDE) FOR WELDS (NOTE E) .......................................... 28

22 APPENDIX A - FABRICATION SPECIFICATION FOR DUPLEX STAINLESS STEEL PIPING ...... 34

23 APPENDIX B - FABRICATION SPECIFICATION FOR NICKEL ALLOYS PIPING ......................... 36

24 APPENDIX C - FABRICATION OF CUPRO- NICKEL PIPING .......................................................... 39

25 APPENDIX D - FABRICATION SPECIFICATION FOR TITANIUM PIPING ..................................... 43

26 APPENDIX E - FABRICATION OF ALUMINIUM PIPING .................................................................. 47

27 SUPPLIMENTAL REQUIREMENTS FOR LICENSORS .................................................................... 52

28 ATTACHMENT-A: TECHNICAL REQUIREMENTS BY CLG ............................................................ 53

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1 SCOPE

1.1 This specification specifies the requirements for field welded fabrication, inspection and testing of pressure and process containing piping and of all welded attachments to that piping.The piping materials covered are:

Carbon and Carbon Manganese Steels (C and C-Mn)

Low Alloy Steels

Austenitic Stainless Steels

Ferritic Stainless Steels

Duplex (and Super Duplex) Stainless Steels

Nickel Alloys

Cu-Ni Alloys

Titanium

Aluminium Alloys

However, this specification shall also apply to circumferential welding of piping components which are fabricated at manufacturer’s shop, such as Strainers, Static Mixers, Silencers, Ejectors, pup piece of valves etc.

< Addition of applicable items >

1.2 Materials for sour service shall comply with the requirements of NACE MR 0103 and NACE RP 0472.

1.3 Materials for High Temperature hydrogen service shall comply with the requirements of API 941.

1.4 For any change required due to exigency /design change, a written Approval is to be obtained from the Contractor before proceeding for any action.

2 CODES AND STANDARDS

2.1 All piping shall be designed and fabricated in accordance with ASME B31.1 and B31.3 modified, API 582 and supplemented by the requirements in this specification.

2.2 Other codes and standards referred to include:

2.2.1 International Standards:

API RP 582(2001 edition): Recommended Practice and Supplementary Welding Guidelines Chemical, Oil & Gas Industries

< as per 1.1 of 3550-8440-SP-0018 >

ASME SEC IX: Welding and Brazing Qualification

Pipe Fabrication Institute Standard ES-24: Pipe bending methods, tolerances, process & material requirements

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EN 1011-2, 2001: Recommendations for Welding of Metallic Materials. Arc Welding of Ferritic Steels

BS 806: Design & Construction of Onshore Boiler Ferrous piping

2.2.2 Project Specifications:

S-000-1360-0002V : Piping Material Specification

S-000-1520-0108V : Positive Materials Identification (PMI) of Alloy Bulk Materials

S-000-1520-0109V : Positive Materials Identification (PMI) at Vendor’s Work

S-000-1670-0007V : Positive Materials Identification(PMI) During Site Fabrication and Erection

S-000-1351-0004V: Submission of Welding and Manufacturing Procedures

3 MATERIALS AND PIPING CLASSES

3.1 All piping materials shall be as specified in the Specification for Piping Materials Classes (Class Index).

3.2 Materials for welded attachments shall match the composition and properties of the pressure part.

4 WELD DESIGN

4.1 Butt Welds

4.1.1 Pipe lengths and butt weld fittings will be generally supplied with ends prepared in accordance with ANSI B16.25

4.1.2 Spool pieces with ends for site fit welding shall be properly shop fabricated to minimise field adjustment.

4.1.3 Whatever the end condition supplied the fabricator shall modify it as necessary to suit the applicable welding procedure.

4.1.4 Permitted radial misalignment of adjacent butt weld preparations shall be no greater than 1.5mm for thicknesses up to 15mm and no greater than 2.5mm for thicknesses greater than 15mm and these will be specified in the WPS accordingly

4.1.5 Internal misalignment in excess of that permitted shall be corrected by machining pipe ends in accordance with ASME B31.3 provided this does not reduce the finished wall thickness below the required minimum wall thickness.

4.2 Branch Welds

Weld details of reinforcement shall be in accordance with Fig. 1 unless specifically modified by other piping drawings. The sizing of welds at weldolets (Fig. 1f) shall be subject to agreement with the Contractor.

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4.3 Welded Pipe Bends

Segmental (mitre) bends shall not be used except for utility water services at ambient temperature for Diam ≥ 60” subject to approval and compliance with ASME B31.3, 304.2.3.

4.4 Proximity of Welds

4.4.1 Designs where the separation (S) between adjacent welds is less than that shown in Figure 2 shall be avoided.

4.4.2 The locations of longitudinal and circumferential pipe welds shall be arranged such that the minimum weld separations are maintained as required by Figure 2.

4.4.3 Where unavoidable circumstances result in adjacent welds closer than that permitted by Figure 2 the following procedures shall be applied to the portion of each weld within the minimum separation.

(i) If both welds are pressure containing welds and the material is carbon or ferritic alloy steel, then a circumferential band that includes each weld shall be stress relieved.

(ii) Each weld shall be considered Examination Class I (See Table 6). Where the second weld or welded attachment will obscure the first, the necessary examination of the first weld shall be performed before the second weld is made.

4.5 Flanges

4.5.1 Flange bolt holes shall straddle the vertical and horizontal centrelines, unless specified otherwise and shall match the orientation of the mating flanges.

4.5.2 Slip-on flanges shall be welded to pipe by inside and outside fillet welds. The inside fillet welds shall be applied so that the flanges do not require refacing. The distance from the flange face to the pipe end shall be equal to the pipe wall thickness plus 3mm.

4.5.3 Internal weld surfaces at orifice flanges and other flow measuring instruments shall be ground flush.

4.5.4 During fabrication, damage to sealing/seating surfaces of flanges and other mechanical joint fittings shall be avoided. In particular such surfaces shall be protected during any PWHT by the application of a suitable coating (e.g. Berkatekt 105).

4.6 Dimensional Tolerances

4.6.1 This section defines dimensional tolerances which are additional to those specified by ASME B31.3. Tolerances are applicable to fabricated piping only and not to the original basic components.

4.6.2 Dimensions indicated as 'A' in Figure 3 shall have the following tolerances depending on nominal pipe size. Where more than one size is included within the dimensions, the smaller size shall govern.

Up to and including 250 900 1200 1500 1800 (mm)

Nom. Pipe Size 10 36 48 60 72 (ins)

(+/-) Tolerance (mm) 3.2 4.8 5.6 6.4 7.2

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4.6.3 Misalignment at flanged or welding ends shall comply with the limits indicated in Figure 3.

5 CUTTING AND WELD PREPARATION

5.1 Cutting Methods

5.1.1 Weld preparations may be cut, gouged or profiled using any mechanical or thermal method, mechanically guided where practicable, except as follows:

5.1.2 For stainless steels, thermal cutting shall be limited to plasma-arc. Arc-gouging and oxy-gas methods are specifically prohibited.

5.1.3 For all materials, excavation of defects and back gouging by oxy gas methods is prohibited.

5.2 Preheat for Thermal Cutting

5.2.1 When thermally cutting carbon and low alloy steels preheat shall be applied in accordance with Table 3.

5.3 Dressing after Thermal Cutting

5.3.1 For all materials, except carbon steel which is to be SAW welded, heat affected base metal shall be removed by grinding or machining back the cut edge by at least 1.5mm.

5.3.2 After grinding or machining, all thermally cut edges of low-alloy steels shall be examined by the magnetic particle method to demonstrate freedom from cracks.

5.3.3 Alternatively if the grinding is performed 3 mm up to 25 mm base material thickness and 5 mm from 25 mm to 50 mm base materials thicknesses then examination by the magnetic particle method is not required

5.4 Cleaning Prior to Welding

5.4.1 Prior to the start of welding, edges and a minimum of 25mm of adjacent material shall be thoroughly cleaned of contaminants which could adversely affect weld quality (e.g. oxide, oils, grease, NDE materials).

5.4.2 For copper/nickel and nickel based alloys, the joint area shall be scratchbrushed, using a stainless steel wire brush reserved for such materials, followed by thorough solvent cleaning. Both operations shall be performed immediately prior to the start of welding.

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6 PIPE BENDING

6.1 General

6.1.1 Pipe bends may be specified either for convenience on small bore systems or where specific long radius bends are required.

6.1.2 Pipe for bending shall include no circumferential butt welds and shall preferably be seamless. Where longitudinally welded pipe is used the weld shall be along the neutral axis of the bend and shall be subjected to 100% crack detection after bending.

6.1.3 The minimum bending radius down to 2D shall be determined by:

(i) Compliance with the dimensional and strain requirements of ASME B31.3 Section 332 post-bending

(ii) Compliance with other requirements of this specification

(iii) Minimum bend radius requirements determined by internal fluid or slurry

6.2 Carbon and Low Alloy Steels

6.2.1 Hot or cold bending may be used. Cold bending shall be performed below 450°C and hot bending shall be performed above 900°C.

6.2.2 Cooling after hot bending shall be in still air to achieve the normalized condition.

6.2.3 The requirement for heat treatment of carbon steel after cold bending shall be in accordance with Table 6.

6.2.4 For the carbon steel pipes having diameters of 1.5 inches and below, cold bending can be carried out without a following stress relief according to the limitation below;

Seamless pipes : Three times nominal diameters by rotary draw bending

Seam welded pipes : Five times nominal diameters

6.2.5 Cold bends in low alloy steels shall be stress relieved in accordance with Table 5-1. < Separating Table 5 to 5-1, for PWHT, and 5-2, for tempering >

6.2.6 Hot formed bends in low alloy steels shall be tempered in accordance with Table 5-2. < Separating Table 5 to 5-1, for PWHT, and 5-2, for tempering >

6.3 Stainless Steels

6.3.1 Whenever possible, bending of stainless steel pipe shall be done cold at ambient temperature. Where the size and schedule of pipe is such that cold bending becomes impracticable hot bending may be carried out.

6.3.2 Hot bending shall be followed by solution heat treatment.

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6.4 Bending Procedures

6.4.1 Any bending, hot or cold and any post-bending heat treatment shall be performed in accordance with a written procedure that has been approved by the Contractor.

6.4.2 All heating and heat treatments shall be performed in a uniform and controlled manner such as fan enclosed furnace, electrical resistance or electrical induction. The use of hand held gas torches is not permitted.

6.5 Standard of Finish

6.5.1 Bends shall be free from buckling, cracks, gouges, corrugations, die marks and heavy scale.

6.5.2 Thickness checks shall be carried out on all pipe bends by ultrasonic or calliper measurement. Checking technique and the extent of its use shall be subject to Approval by the Contractor.

6.5.3 When heat treatment is specified hardness testing shall be carried out to confirm correct heat treatment.

7 FIT-UP AND TEMPORARY ATTACHMENTS

7.1 General

7.1.1 All "fit-up" welds, whether tack welds in the weld groove or welds attaching clips or bridge pieces, shall be performed by welders and weld procedures (including preheat) satisfying the requirements of this specification.

7.2 Removal of Fit-Up Welds

7.2.1 Tack welds in the welding groove shall be either removed or profiled by grinding, before being fused into the finished joint.

7.2.2 Other temporary welds shall be removed by cutting or grinding and shall always be ground smooth with the metal surface. In the case of low alloy steels, areas previously occupied by such welds shall be examined by the magnetic particle method to demonstrate freedom from cracks.

8 WELDING

8.1 General

8.1.1 Applicable Standards

All welding procedures and requirement shall follow API RP 582.

All welding, weld procedures and their qualifications shall fully satisfy the requirements of ASME IX and ASME B31.3.

All welders and welding operators shall be appropriately qualified in accordance with ASME IX, including for tack welding.

8.1.2 Welding Procedures Specifications (WPS)

All welding shall be performed in accordance with written Welding Procedure Specifications (WPS) including all welding variables required by this specification. All WPS shall be submitted for review by the Contractor in accordance with API RP 582.

< Relevant requirements of 3550-8440-SP-0018 are added to this specification >

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WPS shall state or refer to procedural requirements for edge preparation, consumable handling, fit-up and heat treatment where appropriate.

In order to minimise the number of WPS and to allow flexibility, consideration shall be given to specifying appropriate qualified ranges of welding variables.

8.1.3 Additional Essential Welding Variable

In addition to the welding Variable requirements to be stated according to ASME IX the submitted Weld Procedure Specifications (WPS) shall also state the following:

• Typical weld deposition sequence

• Weld bevel and fit-up tolerances

• Electrical characteristics for each welding process and consumable diameter

• Oscillation width and frequency and contact tube-to-weld distance for semi-automatic welding process

• Consumable manufacturer and brand designation

• Heat input, Run Arc Energy of electrode Run-out length (ROL) or run-out ratio (ROR) for SWAW process (impact tested WPS only) and heat inputs for all other welding processes requiring qualification impact testing.

< as per 4.1 of 3550-8440-SP-0018 >

8.2 Welding Processes

8.2.1 Acceptable welding processes subject to the conditions below are:

SMAW or MMA (Shielded Metallic Arc Welding or Manual Metallic Arc)

GTAW or TIG (Gas Tungsten Arc Welding or Tungsten Inert Gas)

SAW (Submerged Arc Welding)

FCAW (Flux Cored Arc Welding)

GMAW (Gas Metal Arc Welding)

8.2.2 GTAW shall be used with the addition of filler metal. GTAW shall be carried out using equipment with a high frequency unit and crater eliminating device. Arc ignition by "touch start" is prohibited. The torch shall have a gas lens.

8.2.3 Self shielded FCAW is not permitted. Use of the gas-shielded FCAW (Flux Cored Arc Welding) process is permitted with Contractor Approval with the following restrictions:

a) FCAW shall be used in the globular/spray transfer modes only.

b) T-2 type wire shall not be used for vertical-up welding.

c) Consumable manufacturer and trade name shall be considered essential variables.

d) Only fabricators with a minimum of 5 years documented experience of FCAW pipe welding shall be selected.

e) FCAW welding shall be limited to carbon steel and austenitic stainless steels.

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8.2.4 Use of the GMAW (Gas Metal Arc Welding) process is only permitted as follows:

a) The dip transfer or short arc mode shall only be used for root welds in combination processes

or for single sided roots and/or full thickness welding of low pressure piping of Class 150 or

lower with a maximum thickness of 12mm.

b) Other applications shall require Contractor Approval and shall be only in the spray-transfer

mode. This will be considered to require an arc current of 200 amps or more unless otherwise

agreed.

8.3 Joint Details

8.3.1 Joint Design

As a minimum, specific joint designs shall be indicated on Vendor drawings or on the WPS. As a minimum, WPS shall indicate the types of joint detail and range of thicknesses applicable to production welds, as well as typical weld deposit sequences applicable. SAW welds shall be multipass.

8.3.2 Full Penetration Welds

All pressure containing butt welds, including branch welds, shall be full penetration welds. This shall be achieved by the following means:

a) For carbon and low alloy steels with up to 2%Cr, a single sided weld with a SMAW or GTAW root run. SMAW electrodes for the root pass in 3" NS pipe shall not exceed 2.5mm wire size. GTAW shall be used for the root pass in less than 3" NS pipe.

b) For low alloy steels with and over 2 ¼ %Cr, austenitic steels and nonferrous metals, a single sided weld with a GTAW or GMAW root run using an inert gas back purge. For austenitic stainless steels the back purge shall be maintained during the first filler pass irrespective of process.

c) If accessible, double sided weld with at least one pass from the reverse side. Prior to second side welding, the root shall be back gouged and ground to sound metal. Any back-gouging and subsequent inspection shall conform to the requirements of Section 5 for thermal cutting.

8.3.3 Run Sequence: The typical run deposition sequence shall be indicated in the WPS. All SAW welds shall be multipass; that is shall be performed with a minimum of two runs.

8.3.4 Backing strips and EB type inserts are prohibited.

8.3.5 Vertical down welding is prohibited.

8.3.6 Peening is prohibited on all passes.

8.3.7 The use of carbon arc-air for gouging shall be subject to the following restrictions:

• Not permitted for use on 300 series stainless steels or non-ferrous alloys.

• The as-gouged surface shall be wire brushed followed by grinding to a bright finish before welding to remove all deposits, dross, etc.

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• Evidence to confirm that arc-air operators have been properly trained and have current experience shall be provided to the Contractor on request.

< as per 10.9 of 3550-8440-SP-0018 >

8.4 Welding Consumables

8.4.1 Specifications & Standards

All welding consumables shall comply with ASME II Part C, BS or DIN standards. Unless specified otherwise, selected consumables shall produce weld deposits matching the base material composition and properties as closely as possible. Recommended SMAW and GTAW consumables are given in Table 1 and Table 2 for joints between similar and dissimilar metals respectively.

FCAW, GMAW or GTAW welding consumables with the designation EXXT-G or ERXXS-G shall not be used.

8.4.2 Brand Names

In addition to specification and classification, WPS shall state actual make and brand name, of each consumable used.

8.4.3 Storage

All welding consumables shall be stored and handled in accordance with maker's recommendations. Consumable handling procedures shall form part of the WPS.

8.4.4 Shielding/Purge Gases

For GTAW or GMAW of austenitic stainless steels the inert gas shall contain not more than 2.0% oxygen.

8.4.5 SAW Fluxes for Austenitic Stainless Steels

The use of SAW fluxes which add alloying elements to the weld deposit, other than those necessary to compensate for arc losses, are prohibited.

8.4.6 Ferrite Content of Austenitic Stainless Steel Welds

Welding consumables for austenitic stainless steels shall be selected to produce weld deposits with ferrite content in the range 3 to 10%. (See Section 11.7 below)

8.4.7 Shielding & Backing Gas

Shielding and purging gases for GTAW welding of Ni alloys shall be in high purity (99.99%) argon or helium.

8.4.8 Preheat and Interpass Temperatures

Unless specifically agreed otherwise minimum preheat shall be in accordance with Table 3. As an alternative EN 1011-2 may be used to determine preheats for carbon-manganese steels.

8.4.9 Interpass Temperatures and Preheat Maintenance

The maximum interpass temperatures, below which the weld must cool before each pass, are as follows:

Carbon and Low Alloy steels : 315°C

Ferritic stainless steel Grade 410 : 315°C

Austenitic stainless steel : 175°C

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Nickel and Cu-Ni alloys : 150°C

Duplex stainless steel : 150°C

8.4.10 For any weld the interpass temperature shall not be allowed to fall below the specified preheat temperature until completion of not less than 30% of final weld depth. Piping shall not be moved until at least 50% of final weld depth is complete.

8.4.11 For low alloy steels, weldments shall not fall below the pre-heat temperature neither between passes nor before PWHT is performed. Where cooling before PWHT is unavoidable an intermediate hydrogen diffusion treatment shall be applied as per Table 4, before slow cooling, under insulation, is permitted.

8.4.12 Where the interpass temperature falls below the specified preheat temperature the preheat level shall always be restored before welding continues.

8.4.13 Preheat and Interpass temperatures shall be measured by indicating crayons, thermocouples, pyrometers or other suitable method referred to in the welding procedure.

8.4.14 Consumable electrodes wires shall carry their trade name brand or classification marking on each individual electrode or wire and reels of wire or strip. Consumables without these identification markings shall not be used. < as per 6.1.4 of 3550-8440-SP-0018 >

8.4.15 Inspection Certificate for Welding Consumables

Each batch of consumables shall be certified, as a minimum, in accordance with ISO 10474 according to material type:

3.1: Impact tested carbon steel, Low alloy (and Advanced Low Alloy) Steel, Austenitic Stainless steel (where ferrite testing or additional corrosion testing is a requirement).

2.2: All other consumables

The original consumable manufacturer’s certificate shall be supplied for each batch irrespective of whether the consumables are purchased directly from the consumable manufacturer or through an agent or distributor. Result of chemical composition analysis for actual purchased lot of welding consumables is required when type 3.1 material test report is required for the welding consumables.

< as per 6.1.7 of 3550-8440-SP-0018 and Attchment-1 of NOM-BG1-TECH-001 >

9 POST WELD HEAT TREATMENT (PWHT)

9.1 PWHT Requirements

9.1.1 As a minimum, all piping materials shall be subject to PWHT when required by the Design Code, for example ASME B31.3 or BS 806.

9.1.2 Additional requirements for PWHT (eg. for low temperature duty, for process duty) shall be as specified in the applicable Piping Material Class.

9.1.3 PWHT of carbon and low alloy steels shall be in accordance with Table 5-1.

< PWHT condition for piping shall be applied to only Table 5-1, as per NOM-BG1-PIP-003 / Attachment-1 / Item 2.8 / H-005 >

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9.1.4 No welding shall be performed after PWHT.

9.1.5 PWHT conditions for other materials (if any) shall be as specified in the applicable piping class or Requisition.

9.2 PWHT Procedures

9.2.1 The WPS shall include all heat treatments to which the weld will be specifically or incidentally subjected. In particular, PWHT procedure shall include full details such as thermocouple location, holding times and rates of heating/cooling, etc.

9.2.2 Austenitic stainless steels shall not be post weld heat treated. When austenitic stainless steels are to be heat treated, appropriate steps shall be taken to ensure that all surfaces are free from non-metallic or low melting point contaminants which could cause embrittlement.

9.3 Proximity of Welds

PWHT is required when weldments are in closer proximity than permitted by Paragraph 4.4 and Figure 2. Such welds shall be heat treated together, either as one heated band during local stress relief or a full furnace stress relief of a complete piping spool.

10 WELDING PROCEDURE QUALIFICATION

10.1 Welding Procedure Requirements < Correction >

10.1.1 Essential and Supplementary - Essential Variables

The requirements of ASME IX or other nominated qualification standard acceptable to the Contractor shall be complied with. In addition, the welding procedure specification shall require re-qualification if any of the changes identified in Section 8.2 or as detailed below are made where impact testing is required:

a) An increase in the specified current range,

b) an increase in the maximum electrode diameter,

c) an increase in the width of weave or a change from string to weave bead technique,

d) an increase in maximum interpass temperature above 250°C,

e) a change of SMAW electrode manufacturer or brand.

10.1.2 When consumables of AWS designation ERXXS-G or EXXT-G are approved for use, the consumable manufacturer and brand designation shall be considered essential variables.

10.1.3 Essential Variable

In addition to other changes in the Essential and Supplementary Variables stated by Code or in other sections of this specification, a welding procedure shall be re-qualified if any of the following additional changes from that stated on the PQR apply:

a) A change in the nominal chemical composition of deposited weld metal, including change from ASME Section IX QW-442 A-No.1 to A-No.2 or vice versa

b) A change in the consumable manufacturer and brand designation for tubular flux cored or metal cored composite wires for FCAW or SAW.

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c) A change between wire chemistry from one AWS classification to another or to wire chemistry not covered by an AWS classification.

d) The manufacturer brand of a flux and wire combination is an essential variable for procedure qualification. Equivalence under ASME Section II, Part C shall not be considered adequate for substitution without re-qualification. SAW procedures shall be re-qualified whenever the welding flux-wire combination, composite-cored electrode or metal powder is changed from one manufacturer’s brand or trade name to another.

< as per 6.1.8 and 5.2.6.1 of 3550-8440-SP-0018 >

10.1.4 Each PQR shall record the Low Alloy Steel consumable manufacturer and brand designation and results of deposited weld metal chemical analysis.

< as per 6.7.3 of 3550-8440-SP-0018 >

10.2 PQR Testing Requirements

In addition to the requirements of ASME IX and the governing code, the requirements of API RP 582 shall be met, and the following procedure qualification testing requirements shall apply:


10.2.1 When impact-tested base materials are specified, the welding procedure qualification shall include Charpy V-notch impact testing. Test specimens shall be taken with the notch in the weld metal, HAZ and base metal. Generally, PQR impact test temperature shall be as specified for the base material. Acceptance criteria for impact shall be as required by 1.5 times of the governing code, except for P-4 and P-5A low alloy steel. For P-4 and P-5A low alloy steel, impact test temperature and acceptance criteria shall be specified as follows:

P-No. Acceptance Criteria and Test Temperature

P-4 34J ave. / 28J min. at minus 18℃

P-5A 54J ave. / 48J min. at minus 29℃

< Refer to NOM-BG1-PIP-003 / Attachment-1 / Item 2.8 / T016 >

10.2.2 Test welds for carbon and low alloy steels shall be subject to a 10Kg Vickers hardness survey of the weld, HAZ and base material on one sectioned face of the weld.

The survey shall be performed along a line parallel to, and within 2mm of:

a) the inside (process side) surface, and

b) the outside surface as per Figure 4.

The indentations shall be spaced as close as practicable in the HAZ and fusion zone. The maximum hardness shall not exceed 248 HV10.

10.2.3 Additional Requirements for Combining Weld Process

Weld procedures which combine welding processes, with the exception of the root and hot passes/2nd passes, shall have each procedure examined for tensile, hardness in WM and adjacent HAZs and (if required) impact properties, individually. Where failure to meet minimum requirements is associated with only one process, the entire WPS + PQR shall be deemed to have failed.

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< as per 5.4.2 of 3550-8440-SP-0018 >

10.2.4 All welding procedure qualification test pieces shall be subject to visual examination to the same standard applicable for the finished production weld. < as per 11.1.2 of 3550-8440-SP-0018 >

10.2.5 Test pieces shall be left for at least 24 hours after welding is completed before NDE and destructive testing is performed. < as per 11.1.3 of 3550-8440-SP-0018 >

10.2.6 Where intergranular corrosion testing of base materials is required, the welding procedure qualification shall be subject to the same test. Test specimens shall be full thickness or taken as close to mid-thickness as possible and shall include the weld on the axis of the bend.

< as per 11.1.7 of 3550-8440-SP-0018 >

11 NON DESTRUCTIVE EXAMINATION (NDE) AND TESTING

All NDE shall follow the requirements from ASME B31.3.


11.1 Examination Class

Each piping class has an examination class that specifies the minimum level of NDE for welds. The examination class for each piping class is determined by the requirements of ASME B31.3, process duty, and material of construction. The general rules for establishing examination class are given in Table 7.

11.2 Extent of NDE

The type and extent of NDE required for each examination class is given in Table 8.

Where the extent indicated is 10%, this is defined as 100% examination of 1 in 10 of those welds indicated. The welds to be examined shall cover each pipe size and each welder, including the first five production weld by each.

11.3 Timing of NDE

11.3.1 NDE should be performed within 48 hours after completion of each weld in order that welder technique and WPS details may be modified in the light of any defects revealed.

11.3.2 For all materials wherever PWHT is specified, all NDE shall be performed after completion of PWHT, except for radiography of carbon steels.

11.3.3 NDE operators shall be certified as follows:

• All Level I, Level II and Level III NDE personnel shall be experienced in pressure vessel examination and hold independent certification by a scheme meeting the requirements of ISO 9712 (e.g. PCN (Personnel Certification in Non-Destructive Testing), CSWIP (Certification Scheme for Welding Inspection Personnel) or ACCP (ASNT Central Certification Program)).

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• Certification by the NDE operator’s employer in accordance with a written practice meeting the recommendations in SNT-TC-1A or ANSI/ASNT CP-189 is required. Original “wet copy” certificates attesting to personnel certification shall be available for review.

< as per 15.2.13 of 3550-8440-SP-0018 >

11.4 Radiographic Examination

11.4.1 All shop examination up to and including 25mm total wall thickness shall use X-radiography. Gamma radiography may be used for thicknesses above 25mm. Gamma radiography could be used on thicknesses of 25mm and below when X-radiography is impractical i.e. construction sites. The gamma source shall be Iridium 192. In any event image sensitivity shall be 2% or better based on source side wire type Image Quality Indicators (IQI).

11.4.2 For ferritic steels, where radiographic interpretation is difficult or where joint geometry or thickness makes radiography impractical, ultrasonic examination may be used in lieu of radiography with the Contractor’s agreement.

11.4.3 Radiography shall meet the requirements of the code and the following:

Sensitivity shall be equal to or better than 2% unless the code requires more stringent limits.

X-ray radiography is preferred. Subject to achieving acceptable sensitivity radiographic film shall fine grain, high contrast type in accordance with ASTM E1815 Type II (e.g. AgfaTM Structurix D7, Fuji IX100 or KodakTM Industrex AA400) for penetrated weld thickness above 10mm and very fine grain, high contrast type in accordance with ASTM E1815 Type I (e.g. Agfa™ Structurix D5, Fuji IX80 or KodakTM Industrex M125) for penetrated weld thickness of 10mm and below.

Gamma radiography may be used for all materials and thicknesses with Type II film (D7 or equivalent) providing the minimum required density and 2% sensitivity source –side according to IQI is attained. For site radiography for thicknesses < 25 mm where X-Ray radiography is not practical, the Gamma radiation source shall be Iridium 192.

< as per 15.2.6 of 3550-8440-SP-0018 >

11.4.4 At least one Image Quality Indicator (IQI) shall appear on each separate radiographic film, with the exception of a panoramic technique where a minimum number of three IQIs shall be used, spaced equally around the circumference. Wire type IQIs shall be in accordance with ASME V or ISO 1027.

< as per 15.2.7 of 3550-8440-SP-0018 >

11.4.5 Only lead intensifying screens may be used in conjunction with radiographic film. Fluorescent intensifying screens are not permitted.

< as per 15.2.8 of 3550-8440-SP-0018 >

11.5 Production Hardness Testing

11.5.1 The requirements of API RP 582 shall be met in full.


11.5.2 For carbon and low alloy steels subject to PWHT and/or post bending heat treatment hardness checks shall be performed on welds and/or bends as follows:

a) where complete spools are furnace heat treated, 10% of welds and 10% of bends in each

furnace charge,

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b) for any other method, 100% of welds and bends. The extent of testing may be reduced at the Contractor’s discretion if satisfactory results are consistently being achieved.

11.5.3 For carbon and low alloy steels in special service, including sour and HF services, hardness checks shall be made on 10% pressure containing weld, on the process side where practicable, with a minimum of one check per 3m of weld.

11.5.4 The test shall be performed by the portable Brinell method according to ASTM E110 using a "Poldi" or a "Telebrineller". For welds each check shall consist of two indents with one in the weld bead and one in the base material as close as practicable to the edge of the weld.

11.5.5 Production macro-hardness values shall not exceed 200 BHN for carbon steel welds, 225 BHN for P-3/P-4 alloy steel welds or 241BHN for P-5A/B alloy steel welds.

< as per TABLE 5 of 3550-8440-SP-0018 >

11.5.6 Production hardness test results and locations shall be recorded.

< as per 12.6.2.6 of 3550-8440-SP-0018 >

11.5.7 Operators of portable hardness testers shall have undergone a training programme in their use. Records of such training shall be made available to Contractor on request.

< as per 12.6.2.7 of 3550-8440-SP-0018 >

11.5.8 If the test fails to meet the required hardness levels, the weld shall either be heat treated and re-tested or completely removed, re-welded and subsequently re-tested.

< as per 12.6.2.8 of 3550-8440-SP-0018 >

11.6 Pressure Testing

11.6.1 All piping shall be capable of passing ASME B31.3 or other applicable design code pressure test requirements in its final erected position at site.

11.6.2 Shop fabricated piping shall be shop pressure tested as per the requirements of the requisition.

11.6.3 The chloride content of the hydrotest water for austenitic stainless steels shall not exceed 50 ppm and the hydrotest temperature shall not exceed 50°C.

11.7 Ferrite Content of Austenitic stainless Steel Welds

Austentitic stainless steel welds subject to stress relief or operating temperature is over 500°C, shall be subjected to a minimum of 3 ferrite checks per weld, with a minimum of one check per 200mm length of manual welds.

Checking shall be by "Ferritescope" or "Permascope" and shall be performed before PWHT (if any). Ferrite levels shall be in the range 3% to 10%.

Where the ferrite determination fails to meet the requirements in this Section, two additional tests shall be performed on the failed weld. If these two additional tests meet the requirements, the weld shall be considered acceptable. If the two tests fail to meet the requirements, the weld shall be removed and re-welded.

< To define the meaning of “service”, and addition as per 16.2.4 of 3550-8440-SP-0018 >

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11.8 Positive Material Identification (PMI)

Alloy and non-ferrous welds, except aluminium, shall be subject to Positive Materials Identification chemical composition checks representing each WPS used on each item.

The extent of the analyses shall conform to the requirements of Project PMI Specifications S-000-1520-0108V, -0109V and S-000-1670-0007V and the limits specified therein for the weld deposit (with regard to the variances permitted by the project PMI Specifications). Alternatively, for critical duties, a more extensive in-situ alloy checking of materials and welds might be required.

11.9 Magnetic Particle Examination

11.9.1 Where MT is specified, the following requirements shall be met:

a) All material/service combinations shall use the electromagnetic yoke method. b) MT of welds shall include a minimum of 25mm of base material either side of the weld

centreline. < as per 15.2.10 of 3550-8440-SP-0018 >

11.9.2 Where wet fluorescent MT (WFMT) is specified, the weld metal and base material for a distance of 25mm either side of the weld centreline, shall be prepared to a surface finish of SSPC-SP3 minimum, with all millscale removed, immediately prior to the examination.

< as per 15.2.11 of 3550-8440-SP-0018 >

12 REPAIRS

The requirements of repair by weld shall be as follows:


12.1 General

12.1.1 Any unacceptable flaws found during NDE shall be repaired in accordance with an approved repair procedure. For major weld repairs, the weld repair procedure shall be submitted for review and approval.

< as per 17.1.1 of 3550-8440-SP-0018 >

12.1.2 Wherever possible, unacceptable flaws shall be removed by grinding or machining. Arc-air gouging is permitted subject to the restrictions in Paragraph 8.3.7.

< as per 17.1.2 of 3550-8440-SP-0018 >

12.2 Inspection

12.2.1 Where removal of a flaw requires subsequent welding to reinstate the required throat thickness, the repair cavity shall be contoured to permit access for welding followed by 100% MT/PT. A qualified welder using a properly qualified WPS shall perform the repair weld. Normally, only SMAW or GTAW shall be used to make the repair weld.

< as per 17.2.1 of 3550-8440-SP-0018 >

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12.2.2 Following welding, the repair area shall be subject to 100% NDE using the same technique(s) as used to detect the flaw initially. Only two repairs at the same location are permitted, thereafter the complete weld shall be removed, re-welded and re-examined.

< as per 17.2.2 of 3550-8440-SP-0018 >

12.2.3 All repairs, production tests and NDE shall be fully recorded.

< as per 17.2.3 of 3550-8440-SP-0018>

13 RECORDS

The Contractor shall maintain accurate and up-to-date records of piping fabrication for each isometric or Contractor’s piping spool drawing.

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14 TABLE 1. WELDING CONSUMABLES FOR SPECIFIC MATERIALS

BASE MATERIAL

CONSUMABLE CLASSIFICATION PER ASME II PART C

SMAW ELECTRODE GTAW OR GMAW WIRE

Carbon Steel: SFA-5.1 or 5.5 E7015/16 or 18 (or SFA-5.1 E6010/11/12 or 13 up to 13mm weld thickness, without notch toughness requirement)

SFA-5.18 ER70S-3 or 6

Low Alloy Steels: (c) 1.25Cr - 0.5Mo 2.25Cr - Mo 5Cr - 0.5Mo 9Cr - Mo

SFA-5.5 E8016 or 18 -B2 SFA-5.5 E9015/16 or 18 - B3 SFA-5.5 E8015/16 or 18 - B6 SFA-5.5 E8015/16 or 18 - B8

SFA-5.28 ER 80S - B2 SFA-5.28 ER 90S - B3 SFA-5.28 ER 80S - B6 SFA-5.28 ER 80S - B8

Austenitic Steels:

Type 304 (a) Type 316 (a) Type 321 or 347 (a)

SFA-5.4 E308 - 15 or 16 (a) SFA-5.4 E316 - 15 or 16 (a) SFA-5.4 E347 - 15 or 16 (a)

(Wires also for SAW) SFA-5.9 ER 308 (a) SFA-5.9 ER 316 (a) SFA-5.9 ER 347 (a)

Nickel Alloys: N02200 (NICKEL 200) (b) N04400 (MONEL 400) (b) N06600 (INCONEL 600) (b) N06625 (INCONEL 625) (b) N08810 (UP TO 900oC) (INCOLOY 800H) (b) N08810 (OVER 900oC) (INCOLOY 800H) (b) N08825 (INCOLOY 825) (b)

SFA-5.11 Eni - 1 SFA-5.11 Enicu - 7 SFA-5.11 Enicrfe - 1 or 3 SFA-5.11 Enicrmo - 3 SFA-5.11 Enicrfe – 2 SFA-5.11 Enicrmo – 3 INCOLOY 135 (b)

(Wires also for SAW) SFA-5.14 ERNi - 1 SFA-5.14 ERNiCu - 7 SFA-5.14 ERNiCr - 3 SFA-5.14 ERNiCrMo - 3 SFA-5.14 ERNiCr – 3 SFA-5.14 ERNiCrMo – 3 SFA-5.14 ERNiFeCr - 1

Cupro-Nickel:

C70600 (90/10) C71500 (70/30)

SFA-5.6 Ecuni or 90/10 CuNi

SFA-5.6 Ecuni

SFA-5.7 ERCuNi or 90/10

CuNi

Duplex Stainless Steels:

1. SAF 2205

2. Ferralium

Sandvik 22.9.3LR

Soudochrom 54462

Metrode 2.9.3LR

Ferralium 225HB

Metrode 25.6.2CuR

Sandvik 22.8.3L

Metrode ER329N

Metrode ER255Cu

Notes:

a) Where L or H grades, or other limits on composition are specified for 304, 316, 321 or 347 then the appropriate limits shall also apply to the welding consumable.

b) Trade name of the INCO group of companies.

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c) Where specifically agreed in writing, small bore (1.5" NS and below) socket/fillet welds, which will not be subject to PWHT, may be performed using SFA-5.11 Enicrfe-2 or 3 or SFA-5.14 ERNiCr-3 consumables. (See Table 5-1)

< Correction >

15 TABLE 2. WELDING CONSUMABLES FOR DISSIMILAR METALS

FIRST BASE MATERIAL

SECOND BASE MATERIAL

CONSUMABLE PER ASME PART C

SMAW ELECTRODE GTAW OR GMAW WIRE

Carbon or Low

alloy or Ferritic

Stainless Steels

Ferritic Stainless

or

Austenitic

Stainless Steels (e)

or

Nickel Alloys (e)

SFA-5.9 E309 (a)(b)

or

SFA-5.11 Enicrfe-2 (c)

or

SFA-5.11 Enicrfe-3 (c)

SFA-5.9 ER309 (a)(b)

or

SFA-5.14 ERNiCr-3 (c)

Carbon Steel

Nickel Alloy N04400

SFA-5.11 Enicu-7

or

SFA-5.11 Enicrfe-2

or

SFA-5.11 Enicrfe-3

SFA-5.11 ERNiCu-7

or

SFA-5.14 ERNiCr-3

Low Alloy Steel

Other Low Alloy Steel Consumable to be selected as per Table 1 for the

lower alloy.

Carbon Steel (f) Low Alloy Steel90/10

Cupro-Nickel

Consumable to be selected as per Table 1 for the

lower alloy.

Carbon Steel or

Austenitic Stainless

Steel

90/10 Cupro-Nickel

SFA-5.14 ERNiCr-3

SFA-5.11 Enicrfe-2

or

SFA-5.11 Enicrfe-3

SFA-5.14 ERNiCr-3

NOTES:

a) Type E310 or ER310 consumables are specifically prohibited.

b) Type E309 or ER309 consumables shall not be used on nickel alloys, neither shall they be used for design temperatures exceeding 315 °C where the second base material is ferritic stainless steel.

c) When welds can be exposed to high temperature, sulphur bearing, reducing process conditions these high nickel alloys shall not be used

d) Where dissimilar base materials have dissimilar PWHT requirements, the detail design, welding and PWHT sequence shall be subject to agreement with Contractor. Specific requirements apply per (e) and (f) below.

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e) Welding austenitic stainless steels or nickel alloys to low alloy or carbon steels requiring PWHT:- "Butter" low alloy or carbon steel with nominal 3mm weld metal before PWHT of low alloy or carbon steel part(s). Complete weld to austenitic stainless steel or nickel alloy without further PWHT.

f) Welding carbon steels to low alloy steels:- "Butter" low alloy with nominal 3mm weld metal before PWHT of low alloy part(s). Complete weld to carbon steel without further PWHT unless required for carbon steel.

16 TABLE 3. PREHEAT FOR CARBON AND LOW ALLOY STEELS

Material

Type

Combined

Thickness (a) (mm)

MINIMUM PREHEAT (℃)

Non-Low

Hydrogen

Welding

Low Hydrogen

Welding (b)

and Thermal Cutting

Extra-Low

Hydrogen Welding (c)

Carbon Steel (d)

(Up to and

including

450 N/mm2 min.

specified UTS)

Up to 30

Up to 40

Up to 50

Up to 60

Over 60

10

75

100

125

150

10

10

10

10

50

10

10

10

10

10

Carbon Steel (d)

(over 450 N/mm2

min. specified UTS)

Up to 20

Up to 30

Up to 40

Up to 50

Up to 60

Over 60

Not Permitted 10

100

125

150

150

150

10

20

75

100

125

150

1Cr - 0.5Mo or

1.25Cr - 0.5Mo

Up to 35

Up to 50

Over 50

150

175

200

Under conditions of high restraint use extra-low hydrogen process with pre-heats per low hydrogen process

2.25Cr - Mo

5Cr - 0.5Mo or

9Cr - Mo

All thicknesses 250

NOTES:

a) Combined thickness is the sum of material thicknesses which provide a heat conductive path away from the weld/cut. (Refer to BS5135 for guidance).

b) Low hydrogen processes are those processes with basic type coatings/fluxes yielding less than 10ml hydrogen per 100g weld metal.

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c) Extra-low hydrogen processes are those processes yielding less than 5ml hydrogen per 100g weld metal including SMAW and SAW with basic type coatings/fluxes and GTAW and GMAW processes.

d) For carbon steels, reduced preheats may be calculated using EN 1011-2, however, the WPS shall clearly indicate any assumptions affecting maximum carbon equivalent, minimum welding current/arc and maximum weld hydrogen contents.

17 TABLE 4. HYDROGEN DIFFUSION HEAT TREATMENT FOR LOW ALLOY STEELS

Thickness (mm) Holding time in hours

150℃ 200℃ 250℃ 300℃

Up to 10 See Note 1

Up to 20 1 1 1

Up to 30 6 3 2 1

Over 30 10 7 5 3

NOTES:

1. For thicknesses below 10mm the cooling from preheating to ambient temperature shall be under an insulated cover.

18 TABLE 5-1. PWHT OF CARBON AND LOW ALLOY STEELS

MATERIAL TYPE

THICKNESS

WHERE PWHT

REQUIRED (MM)

HOLDING

TEMPERATURE (℃)

TIME AT HOLDING TEMPERATURE (MINUTES)

PER MM MINIMUM

Carbon steel Up to 20 (a) Over 20

605 – 630(c) 605 – 630(c)

2.5 2.5

60 60

1Cr - 0.5Mo or 1.25Cr - 0.5Mo

All (b) 704 - 729 2.5 60

2.25Cr - Mo All (b) 704 - 729 2.5 120

5Cr - 0.5Mo or 9Cr - Mo

All (b)

704 - 729 2.5 120

NOTES:

a) Except where specifically required by the governing code, or called for in the piping class for process or other reason, PWHT is not generally required for carbon steel up to and including 20 mm thick.

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b) Where specifically agreed in writing, PWHT is not required for small bore (1.5" NS and below) socket/fillet welds performed using SFA-5.11 Enicrfe-2 or 3 or SFA-5.14 ERNiCr-3 consumables. (See Table 1).

c) For carbon steel piping components which are fabricated at manufacturer’s shop and have “Amine Service” or “Caustic Service” in Purchaser’s description, shall be post weld heat treated at 620 degree C minimum.

< Refer to NOM-BG1-PIP-003 / Attachment-1 / Item 3.4 / clarification 2 >

TABLE 5-2. TEMPERING OF POST HOT FORMED BEND FOR LOW ALLOY STEELS

MATERIAL TYPE

THICKNESS

WHERE PWHT

REQUIRED (MM)

HOLDING

TEMPERATURE (℃)

TIME AT HOLDING TEMPERATURE (MINUTES)

PER MM MINIMUM

1Cr - 0.5Mo or 1.25Cr - 0.5Mo

All 730 min 2.5 60

2.25Cr - Mo All 730 min 2.5 120

5Cr - 0.5Mo or 9Cr - Mo

All 730 min 2.5 120

< TABLE 5 is separated to TABLE 5-1 for PWHT, and TABLE 5-2 for Tempering of after hot forming >

19 TABLE 6. POST BENDING HEAT TREATMENT FOR CARBON STEELS

MATERIAL

AND SERVICE

HEAT TREATMENT

CALCULATED ELONGATION OF OUTER FIBRE (e) Note (a)

e < 5% 5% < e < 10% 10% < e < 20%

e >20%

NON-IMPACT-TESTED

(SOUR SERVICE NOT SPECIFIED)

NO HEAT

TREATMENT REQUIRED

NO HEAT

TREATMENT REQUIRED

SR N

NON-IMPACT-TESTED

(SOUR SERVICE SPECIFIED)

NO HEAT

TREATMENT REQUIRED

SR SR N

IMPACT-TESTED (ALL SERVICES)

NO HEAT

TREATMENT REQUIRED

SR N N

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SR = Stress relieve in accordance with Table 5-1 of this Specification.

<Correction>

N = Normalize.

NOTE:

a) 'e' shall be calculated by: e=t/2r : r=bend radius t=pipe O.D.

20 TABLE 7. EXAMINATION CLASSES

TYPE OF MATERIAL

EXAMINATION CLASS (ANSI RATING) CLASS 1 CLASS 2 CLASS 3 CLASS 4

CARBON STEEL(d)

900 - 2500 150 - 600 - 150(b)

LOW TEMP.

CARBON

STEEL

150 - 2500

LOW ALLOY STEEL

150 - 2500 - -

CEMENT LINED C.S.

- - ALL -

AUSTENITIC

STAINLESS STEEL

900 - 2500 150 - 600 - -

CUPRO-NICKEL 150 - 2500 - - -

TITANIUM 150 - 2500 - -

DUPLEX

STAINLESS STEEL

150 - 2500 - -

NICKEL ALLOY

150 - 2500 - - -

NOTES:

a) This table is for information only. Examination class is specified in the appropriate piping class.

b) Non-hazardous duties only (e.g. water, air, or nitrogen with design temperature below 400℃).

c) Examination class is listed in Table 8.

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d) Low temperature carbon steel which MDMT is down to minus 45 degree C, shall be applied Class 1.

< To add material type “Low temperature carbon steel” to TABLE 7, as per NOM-BG1-PIP-003 / Attachment-1 / Item 2.8 / T-007 >

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21 TABLE 8. EXTENT OF EXAMINATION (NDE) FOR WELDS (Note e)

EXAMINATION

CLASS

EXAMINATION

METHODS

APPLICABLE

MATERIALS

BUTT

WELDS

BRANCH

WELDS

FILLET/

SOCKET

WELDS

ATTACHM

ET WELDS

I Visual

Radiography

(Note a)

Mag. Particle

Dye Penetrant

All

All

CS, Low Alloy

Steel

Austenitic SS,

Duplex SS &

non ferrous

100

100

100

100

100

-

100

100

100

-

100

100

100

NR

100

100

II Visual

Radiography

(Note a)

Mag. Particle Dye Penetrant

All

All

CS

Austenitic SS&

nonferrous

100

10

10

10

100

-

10

10

100

-

10

10

100

NR

10

10

III (Note b)

Visual Mag. Particle

CS

CS

100

NA

100

NA

100

100

100

100

IV (Note c)

Visual Radiography

All

All

100

(Note d)

100

-

100

-

100

-

NA: Not Applicable NR: Not Required

NOTES:

a) As per 11.4.2 ultrasonic examination may be utilised when radiography is inappropriate.

b) Examination Class III is applicable to carbon steel concrete lined pipe.

c) Examination Class IV will not normally be used on pressure containing pipework.

d) Fire water Services: 10% Radiography Amine Services: 100% Radiography Concrete lined site joints: Random radiography

e) Extend of NDE for each line class shall be in accordance with section 11 of S-000-1360-0002V. < To delete radiography requirement for fillet/socket welds from examination class I and II, as per NOM-BG1-PIP-003 / Attachment-1 / Item 2.8 / T-007 >

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DIMENSION FOR ROOT FACE AND GAP THICKNESS SMAW GTAW/GMAW

(mm) g(mm) f(mm) g(mm) f(mm)

< 22 1.6-4.0 0.8-2.4 0.8-1.6 1.2-2.5

> 22 2.5-4.0 0.8-2.4 1.6-3.0 1.2-2.5

Figure 1 A), B), C), D) - Branch reinforcement design

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NO TES:

1. SPECIFIC REQUIREMENTS ARE GIVEN IN PIPING DRAWINGS.

2. REINFORCEMENT PADS MAY BE SPLIT CIRCUMFERENTIALLY OR ALONG THE AXIAL CENTRELINE AND REWELDED TO THE HEADER BY FULL THICKNESS/FULL PENETRATION WELD.

3. IN ALL CASES THE REINFORCING PAD SHALL BE ATTACHED AFTER THE BRANCH TO HEADER WELD HAS BEEN MADE AND EXAMINED.

4. IF THE CROTCH WELD ROOT AT E CANNOT BE MADE FROM THE OUTSIDE WITH RELIABLE PENETRATION THEN IT SHALL BE MADE FROM THE INSIDE

Figure 1 E) and F) - Branch reinforcement design

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SEPARATION S = Sp OR Sa AS APPLICABLE

WHERE Sp = SEPARATION BETWEEN ANY TWO PRESSURE CONTAINING WELDS

=√(D x t) (mm) MINIMUM

AND = SEPARATION BETWEEN AN ATTACHMENT WELD AND ANY OTHER WELD

= THE LESSER OF 2t OR 40mm MINIMUM

Figure 2 - Proximity of welds

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Figure 3 - Dimensional tolerances of fabricated piping

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With

in 2

With

in 2

Figure 4 - PQR hardness testing

< Correction of survey points as section 10.2.2. >

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22 APPENDIX A - FABRICATION SPECIFICATION FOR DUPLEX STAINLESS STEEL PIPING

A1. SCOPE

This Appendix covers the special requirements for the fabrication of duplex stainless steel piping.

The following points shall be taken into account during fabrication of duplex stainless steels.

A2. GENERAL

A2.1 Fabrication of these materials shall be carried out in an area separate from that used for carbon/low alloy steels and copper alloys.

A2.2 Saws, grinders and other tools used on duplex stainless steel shall not be used on other materials. Bare carbon steel equipment is not acceptable.

A3. WELDING

A3.1 Preparation

A3.1.1 Cutting shall be by cold sawing or plasma-arc process. Fused edges and heat-affected zone from plasma-arc cutting shall be removed by grinding or machining.

A3.1.2 Welders shall be equipped with and shall wear clean gloves for handling duplex stainless steels and their filler materials.

A3.1.3 All low melting point materials including copper, lead and zinc compounds shall be removed from the fabrication areas.

A3.1.4 Due care and attention shall be taken during installation and particularly hook-up where overspray of zinc containing coating must be avoided.

A3.2 Essential Variables & PQR

A3.2.1 Only Approved materials shall be used for the PQR test.

A3.2.2 The following changes shall require requalification:

Any increase in heat input greater than 20% of the maximum reached during the qualification

test.

Any change in backing gas conditions including gas composition, flow rate, damming

method or oxygen levels in backing gas enclosure outside those reached during the

qualification test.

A3.2.3 Corrosion test and/or Impact Testing

Either an impact test or corrosion test as part of the weld procedure qualification is required. An

impact test is the preferred option over the corrosion test.

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A4. INSPECTION AND TESTING

A4.1 Non-Destructive Examination

A4.1.1 The extent of radiographic examination shall be as indicated in Tables 7 & 8.

A4.1.2 All welds in duplex stainless steel shall additionally be 100% examined by dye penetrant method, as indicated in Table 8.

A4.2 Acceptance Criteria

The following features are unacceptable:

Any cracks

Any lack of fusion or lack of penetration at the bore surface

Surface-breaking porosity.

A5. REPAIR

Only one repair per weld is permitted. Should the repair contain unacceptable defects the complete weld shall be cut-out.

A6. PIPE SUPPORTS

When welding directly on to pressure retaining components of thin wall internal gas purging shall be required to prevent oxidation/discolouration.

A7. INSTALLATION

For installation and hook-up activities the sequence of hook-up welding shall be planned for backing

gas protection.

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23 APPENDIX B - FABRICATION SPECIFICATION FOR NICKEL ALLOYS PIPING

B1. SCOPE

B1.1 This Appendix covers the special requirements for the fabrication of nickel alloys piping.

B1.2 This Appendix applies to the following materials:

- UNS alloy N04400 ('Monel 400')

- UNS alloy N06600 ('Inconel 600')

- UNS alloy N06625 (‘Inconel 625’)

- UNS alloy N08825 (‘Incoloy 825’)

- UNS alloy N10276 ('Hastelloy C-276')

and any other nickel based alloys designated by the Contractor (i.e. materials in which

nickel is the major constituent).

B2. GENERAL

B2.1 Fabrication of nickel alloys shall be carried out in an area separate from that used for carbon steels/low alloy steel/copper alloys.

B2.2 All welding and heat treatment operations on nickel alloys shall be carried out in conditions consistent with the avoidance of contamination.

B2.3 The Fabrication area shall be kept clean, draught-free and shall be totally enclosed. Shop welding shall be carried out in conditions consistent with the avoidance of contamination.

B2.4 Saws and other tools used on a nickel alloy shall be clean and shall not have been previously used on other materials. Only stainless steel wire brushes shall be used; these shall be reserved exclusively for workpieces of one particular nickel alloy and clearly marked as such. Bare carbon steel tools or equipment are not acceptable.

B2.5 Care shall be taken to avoid liquid metal embrittlement due to contact with low melting point metals and also pick-up of carbon or sulphur. Consideration shall be given to restricting the use of temperature-indicating crayons, marking ink, grease, etc.

B2.6 Forming and bending of nickel alloys during fabrication shall be carried out at or below 190oC. Hot working is not allowed.

B2.7 Grinding wheels or discs shall be iron-free and shall not be organic resin bonded.

B2.8 Nickel alloys shall be heat treated to remove the effects of any cold working in excess of 5% fibre strain, prior to welding. Heat treatment shall be performed according to an Approved procedure.

B2.9 Any heat treatment shall be done in an electric furnace or a furnace heated by a sulphur-free fuel.

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B3. WELDING

B3.1 Preparation

B3.1.1 Cutting shall be by cold sawing or plasma-arc process. Fused edges and heat-affected zone from plasma-arc cutting shall be removed by grinding or machining. The joint area shall be scratch brushed and solvent cleaned immediately prior to welding.

B3.1.2 Welders shall be equipped with and shall wear clean gloves for handling nickel alloys and their filler materials.

B3.1.3 Due care and attention shall be taken during installation and particularly hook-up where overspray of zinc-containing coatings on to nickel alloys must be avoided.

B3.2 Process

B3.2.1 Gas Tungsten Arc Welding (GTAW) shall be used for root runs of single-sided welds.

B3.2.2 Submerged arc welding (SAW) shall not be used, except for welding of heavy sections with prior Approval, when heat input shall be restricted at 4kJ/mm maximum.

B3.2.3 Brazing is not permitted.

B3.2.4 Autogenous welding is not permitted.

B3.3 Consumables

B3.3.1 Consumables selection shall follow Table B “Nickel-Based Alloys and Dissimilar Welding”.

< Relevant part of Table A-3 of API RP582 is attached to this specification >

B3.3.2 Consumables for dissimilar metal joints shall follow Table B “Nickel-Based Alloys and Dissimilar Welding”.

< Relevant part of Table A-3 of API RP582 is attached to this specification >

TABLE B. Nickel-Based Alloys and Dissimilar Welding

Base Material

(Note1) Allo

y 40

0 (N

0440

0)

Allo

y 60

0 (N

0660

0)

Allo

y 62

5 (N

0662

5)

Allo

y 82

5 (N

0882

5)

Allo

y C

-276

(N

1027

6)

Carbon and Low Alloy Steel B,C A A A D

300 Series Stainless Steel A,C A A A D

400 Series Stainless Steel B A A A D

Alloy 400 (N04400) B A A A A

Alloy 600 (N06600) - A A,E A D,E

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Alloy 625 (N06625) - - E E D,E

Alloy 825 (N08825) - - - E D,E

Alloy C-276 (N10276) - - - - D

Type of Welding Consumable

A: B: C: D: E:

AWS 5.11, Classification ENiCrFe-2 or 3 AWS 5.11, Classification ENiCu-7 AWS 5.11, Classification ENi-1 AWS 5.11, Classification ENiCrMo-4 AWS 5.11, Classification ENiCrMo-3

(Note 1)

Table B refers to coated electrodes. For bare wire welding(SAW, GMAW, GTAW), use equivalent electrode classification(AWS A5.14).

< Relevant part of Table A-3 of API RP582 as above (This table called “Table B”)>

B3.4 Heat Control

B3.4.1 Pre-heat shall not be used; however, the temperature of the joint surfaces shall not be less than 20oC before commencement of welding.

B3.4.2 The interpass temperature shall be 150oC maximum, checked by means of a contact thermometer. For Alloy UNS NO8825, the interpass temperature shall be 120oC maximum.

B3.4.3 Post weld heat treatment shall not be used, except with prior Contractor Approval for certain dissimilar metal joints.

B3.5 Shielding and Backing Gas

B3.5.1 Backing gas shall be used for the duration of welding to prevent oxidation of inner surface. Shielding and backing gas shall be high purity argon (99.995%).

B3.5.2 The extent of gas purging and the method of confirming the backing gas shall be specified on the WPS.

B3.5.3 The flowrate shall be minimum 15 litres per minute.

B3.5.4 The removal of oxygen shall be confirmed by ensuring at least 6 volume changes of gas in the backing gas enclosure and by oxygen monitoring. The backing gas enclosure shall contain less than 0.5% oxygen before and during welding.

B3.5.5 Heavy oxidation as indicated by a dark brown to dark blue colour with possible coked weld surface is unacceptable.

B3.5.6 If unacceptable oxidation is found, the surface shall be lightly ground with abrasive paper (60-35 micron grade). Coarse ground surfaces are detrimental to the corrosion resistance of the material and shall be avoided.

B3.5.7 If access to the root is impossible the oxidised surfaces shall be removed by pickling to an Approved procedure.

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B3.6 Welding Procedure Specifications (WPS)

The WPS shall contain full details of backing gas conditions including gas composition, flowrate, closing down type and maximum oxygen content in backing gas closure.

B3.7 Essential Variables

B3.7.1 Only Approved materials shall be used for the qualification test.

B3.7.2 Heat input and interpass temperature shall not exceed that recorded during the qualification test.

B4. CLEANING OF ASSEMBLY

B4.1 All traces of welding slag, spatter, scale or other such material shall be removed from the fabricated assembly.

B4.2 Joints shall be scratch brushed to produce a clean, bright surface prior to inspection.

B5. INSPECTION

B5.1 All joints shall be examined as required by the Code.

B5.2 Welded joints shall be 100% visually examined and 100% liquid penetrant inspected. Butt joints shall also be radiographically tested. Acceptance criteria shall be as stated in the Code, except that lack of root penetration in excess of 1.6 mm is not permitted.

B5.3 Pressure-containing assemblies shall be leak tested as required by the Code.

B6. REPAIR

Only one repair is permitted per weld. When the repair contains unacceptable defects the complete weld shall be removed.

24 APPENDIX C - FABRICATION OF CUPRO- NICKEL PIPING

C1. SCOPE

C1.1 This Appendix covers the special requirements for the fabrication of cupro-nickel alloy piping materials and other copper alloy piping materials.

C1.2 This specification applies to 90/10 cupro-nickel (UNS C70600) and 70/30 cupro-nickel (UNS C71500/C716400) and copper alloy materials specified by the Piping Materials Specification.

C2. GENERAL

C2.1 All welding and brazing operations shall be carried out in conditions fully suitable for the

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production of sound uncontaminated welds. Welding operations shall be carried out away from the fabrication of other materials, in particular, the environment for welding and brazing of cupro-nickel shall be segregated from that associated with the working and welding of steel.

C2.2 Wrought cupro-nickel is often used in conjunction with fittings and valves of other alloys, e.g. nickel-aluminium-bronze. Cupro-nickel shall not be welded to materials other than itself, but may be brazed to components which are specifically intended for brazed connection. Leaded or free machining alloys shall not be brazed.

C2.3 Care shall be taken to avoid contamination of weld areas by temperature-indicating crayons, marking inks, grease, etc.

C3. WELDING

C3.1 Preparation

C3.1.1 Material shall be cut by either cold sawing with sulphur-free lubricant or plasma-arc thermal cutting. After plasma-arc cutting, fused and heat-affected material shall be removed by machining or grinding. The joint area shall be scratch brushed using a wire brush used only for copper-nickel materials. This shall be followed by thorough solvent cleaning immediately prior to start of welding.

C3.1.2 Grinding wheels or discs shall be iron-free and shall not be organic resin bonded.

C3.1.3 GTAW and GMAW filler wire shall be abraded with stainless steel wool and degreased, immediately before use.

C3.1.4 Welders shall be equipped with and shall wear clean gloves for handling workpiece and filler materials.

C3.2 Welding Process Requirements

C3.2.1 Gas Tungsten Arc Welding (GTAW) shall be used for all root runs and normally for capping runs also.

C3.2.2 Gas Metal Arc Welding (GMAW) or Shielded Metal Arc Welding (SMAW) may be used for capping runs on joints of 5mm or greater thickness.

C3.2.3 Shielding and purging gas shall be oxygen-free argon, helium or argon/helium mixture. Back purging shall be maintained during all welding, this shall include tacking and capping runs.

C3.2.4 The arc length shall be kept as short as possible to maintain the integrity of the gas shield. The Contractor shall use transparent or translucent gas nozzles to achieve this, where possible.

C3.2.5 SMAW electrodes shall be 3.25mm or smaller diameter core size. Bead width shall be restricted to four times electrode core diameter, maximum.

C3.2.6 To overcome stop/start porosity, the arc shall be struck at the ends of the previous run and then tracked backwards to remelt all of the previous end crater before proceeding with welding in a forward direction.

C3.2.7 All slag and tarnish shall be removed between runs and prior to resumption of welding, a bright surface shall be achieved by scratch brushing.

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C3.3 Filler Materials

C3.3.1 All filler materials for cupro-nickel shall be nominal 70% copper/30% nickel composition.

C3.3.2 Cupro-nickel welding consumables shall be totally segregated from other materials and should normally be stored within the 'clean' shop area.

C3.4 Heat Control

C3.4.1 Pre-heat shall not be used; however the temperature of the joint surfaces shall not be less than 20oC before commencement of welding.

C3.4.2 Interpass temperature shall be 150oC maximum, checked by means of a contact thermometer.

C3.4.3 Welding heat input shall be optimised to prevent lack of fusion.

C3.4.4 Post weld heat treatment shall not be used.

C4. BRAZING

C4.1 Materials

C4.1.1 Brazing shall generally be carried out using proprietary heavy duty silver-brazing fittings with insert silver brazing alloy.

C4.1.2 Filler material for brazing shall conform to a specification categorised as ASME IX F No 102 with a minimum of 50% silver.

C4.2 Preparation for Brazing

C4.2.1 The workpiece shall be suitably sized and positioned to obtain a fine clearance in the joint consistent with capillary filling of the joint during brazing.

C4.2.2 Pipe ends shall be cut square. Joint preparation and adjacent surfaces shall be abraded using fine glass or emery paper, immediately before brazing.

C4.2.3 After abrading joint surfaces, silver brazing flux shall be mixed and brushed on to the joint surface. If the flux does not adhere well, surfaces should be degreased and flux re-applied. The two halves of the joint shall be brought into contact whilst the flux is wet.

C4.3 Brazing Operation

C4.3.1 Torch heating shall be by oxy-fuel torch using 'soft', neutral or slightly reducing flame.

C4.3.2 Heat shall be applied evenly to joint, bringing joint to brazing temperature approx. (670oC minimum) as quickly as possible.

C4.3.3 Satisfactory joining is indicated by the presence of smooth, uniformly-visible brazing alloy at the mouth of the joint. Further brazing alloy may be added to the joint to achieve complete joining, but excess braze shall be avoided.

C4.3.4 Heating shall continue for 15-20 seconds after melting, to develop full joint strength.

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C5. PIPE BENDING

The requirements of Sections 6.1, 6.4 and 6.5 of the main Specification apply plus the following:

C5.1 All pipe bending shall be done cold at ambient temperature. Hot bending is not permitted.

C5.2 Any filler materials used shall be free from sulphur, lead, bismuth, antimony and any other elements that are likely to result in intergranular cracking.

On completion of bending all internal and external surfaces shall be thoroughly cleaned of all filler material and other foreign material.

Filler materials and method of removal and cleaning shall be included in the bending procedure.

C5.3 10% of bends from each batch (minimum of one per batch) shall be hardness tested using a portable hardness tester. A batch shall consist only of pipe of the same diameter and wall thickness formed to the same bend radius. Bends shall be tested on the external surface of the bend extrados and a minimum of 3 tests per bend shall be made.

C5.4 If any hardness value exceeds 100 HV the complete batch shall be annealed at a temperature of between 750oC and 800oC for a minimum period of 10 minutes.

C6. CLEANING OF ASSEMBLY

C6.1 All traces of welding slag, brazing flux, spatter, scale or other such material shall be removed from the fabricated assembly.

C6.2 Joints shall be scratch brushed to produce clean, bright surfaces prior to inspection.

C7. INSPECTION

C7.1 All joints shall be examined as required by the Code and Table 8.

C7.2 Brazed joints shall be 100% visually examined and each shall have a uniform, complete line of brazing alloy at the mouth of the joint.

C7.3 Welded joints shall be 100% visually examined and 100% liquid penetrant inspected. Butt joints shall also be radiography tested to the extent specified in Table 8. Acceptance criteria shall be as stated in the Code, except that lack of root penetration and root penetration in excess of 1.6mm are not permitted.

C7.4 Pressure-containing assemblies shall be leak tested by a Code specified method.

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25 APPENDIX D - FABRICATION SPECIFICATION FOR TITANIUM PIPING

This appendix gives additional requirements for fabrication, inspection and testing of commercially pure, grade 2 Titanium piping.

D1. GENERAL

D1.1 The corrosion resistance and mechanical properties of titanium are very sensitive to contamination that may occur during fabrication by pick up from the environment and from tool surfaces. Storage arrangements shall be selected with this in mind.

D1.2 All fabrication work shall be carried out in an atmospherically controlled room completely separate from areas where other materials are fabricated. The room shall be designed to be clean and shall be circulated with filtered air. Air velocity shall be low enough not to cause disturbance of welding shield and purge gas.

D1.3 The fabricator's proposed work area, work practices and equipment shall be subject to inspection by the Contractor before fabrication commences.

D1.4 All tools used shall only previously have been used on titanium. All such tools shall be maintained with clean surfaces.

D2. CUTTING AND WELD PREPARATION

D2.1 Thermal cutting shall be by the plasma arc process. Prior to cutting the areas within 50mm of the cut shall be cleaned as per Section B3.1. The cut edge shall be lightly machined or ground back to remove all oxidised and heat affected materials to produce a surface free from cracks, voids and scores.

D2.2 Mechanically cut edges shall be lightly ground to give the same standard of surface finish as per D2.1. Chlorinated cutting fluids shall not be used. Grinding shall be light enough to prevent burn marks.

D3. CLEANING PRIOR TO HOT WORK

D3.1 Cleaning before hot work is necessary to remove all surface contamination by foreign matter. Cleaning shall be by brushing with stainless steel or titanium wire brushes or buffing using abrasive or cloth. Under no circumstances should steel brushes or steel wool be used on titanium.

D3.2 Following brushing and abrading the area shall be degreased using a non-chlorinated solvent such as ethanol, propanol or acetone. Industrial methylated spirit shall not be used. The solvent shall be applied using clean, lint free cloths or cellulose sponges and no residues shall remain.

D4. WELDING

D4.1 All welding shall be carried out under atmospherically controlled conditions (section D.1.2).

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D4.2 Good joint fit up is essential to minimise root burn through, control underbead contour and prevent contamination from air trapped in the joint. Tolerances for difference in I.D. at the weld of abutting components and for misalignment shall be 0.8mm.

D4.3 Immediately prior to welding internal and external areas 50mm from the weld shall be cleaned as per para D.3. Once cleaned, joints shall be carefully preserved and handling shall be minimised.

D4.4 Any tack welds shall be made exercising the same care in cleaning and inert gas shielding as for all titanium welding. Tack welds shall only be incorporated into the root run of the main weld if they are sound and uncontaminated.

D4.5 The welding process shall be Gas Tungsten Arc (GTAW).

D4.6 An inert gas secondary trailing shield of high purity argon or helium shall be used during all welding. The railing shield shall be designed to protect the solidified weld metal and associated HAZ until temperature falls below 400oC.

D4.7 Butt welds shall have an inert gas back purge to protect the root side of welds and HAZ. This shall be maintained during tack welds, the root run and all subsequent passes until the weld is complete and cooled below 400oC. Maximum interpass temperature shall be 200oC.

D4.8 The arc shall be struck only where the weld is to be made.

D4.9 If the tungsten electrode makes contact with the work, either the base metal or weld metal, the touch down area shall be ground to remove any tungsten pick up.

D4.10 When the welding process is interrupted the filler wire shall be cooled in the gas purge otherwise the heated end shall be discarded.

D4.11 Welding wire shall conform to AWS ER Ti-3.

D4.12 Each weld run shall be wire brushed with a titanium wire brush before the next run is deposited.

D5. PQR TESTING REQUIREMENTS

D5.1 In addition to the testing called for in Section 10.2 of the main specification the following tests are required:

- Two macrosections shall be taken from the test specimen for each PQR.The macrosections shall be ground, polished and examined for penetration and fusion at the root and freedom from significant defects.

- Test specimens shall be subject to a 10Kg Vickers hardness survey. A minimum of three traverses shall be made across the weld cross section with measurements in the weld metal and both HAZ's and parent material during each traverse. No hardness level in the weld of HAZ shall exceed by more than 20 points the average hardness of the adjacent parent metal.

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D6. PIPE BENDING

Pipe Bends shall not be used. All changes in direction shall be by the use of fittings.

D7. INSPECTION

D7.1 Titanium welds shall also be visually examined for indications of contamination after each pass. All weldments shall be examined in the as-welded condition. Weldments shall not be ground, brushed or dressed in any way that removes surface colouration before inspection by Contractor has been carried out.

If attempts are made to remove indications of contamination the weld(s) concerned shall be liable to rejection.

D7.2 The surface of the weld, HAZ and adjacent parent metal shall not show any colouration darker than light straw.

If there is any doubt about the weld purity a hardness survey using a portable hardness tester shall be carried out under the guidance of the inspector. The hardness measurements in the weld and HAZ shall not exceed those of the parent metal by more than 20 points on the Vickers Hardness Scale.

D8. NON-DESTRUCTIVE EXAMINATION

D8.1 All buttwelds shall be 100% examined by radiographic testing (RT), using an aluminium image quality indicator (IQI) if titanium IQI is not available.

D8.2 All welds shall be 100% examined by dye penetrant inspection method (DPI).

D8.3 The following features are unacceptable:

Any cracks (cracking is usually due to iron contamination)

Any lack of fusion or lack of penetration

Porosity in linear formation and in line with root face.

Surface-breaking porosity

D9. REPAIR OF DEFECTIVE WELDS

D9.1 Repair welding is not permitted. Surface dressing with a clean file or grinder may be used to correct minor surface imperfections, provided that the minimum design thickness is maintained.

D9.2 Any welds which have been rejected because of cracking, porosity, lack of fusion, discolouration or excessive hardness shall be completely removed. When embrittlement is suspected because of evidence of cracking, discolouration or excessive hardness, heat affected zones adjacent to the defective weld shall also be cut out.

D9.3 Material which has been rejected due to contamination from arc strikes or fusion of other metals to the titanium surface shall not be repaired but shall be cut out and scrapped.

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D10. IRON CONTAMINATION TEST FOR TITANIUM COMPONENTS (Ferroxyl Test)

The test solution is made up by dissolving 7 g of potassium ferricyanide and 4.5 ml of nitric acid (65% concentration) in 214 ml of distilled water. The test solution deteriorates in a few days, becomes cloudy, and must therefore be used shortly after it is made up. The test may be done in two ways:

- Soak a filter paper in the solution and apply this is to the surface under examination, ensuring good contact over the whole area. The presence of iron is revealed by a blue colouration almost immediately after application of the paper in those areas which contain contamination.

- Swab or spray the whole surface to be tested using the solution. Iron contamination is revealed by blue colouration. It may be helpful to increase the viscosity of the solution by the addition of iron-free gelatine (or similar agent) and this will be permitted as long as it is demonstrated that the presence of the gelatine does not interfere with the sensitivity of the test.

- A titanium surface is considered to have failed the test if blue colouration develops within 5 minutes of the application of the test solution.

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26 APPENDIX E - FABRICATION OF ALUMINIUM PIPING

E1. SCOPE

The scope of this appendix is to define the technical requirements for the welding and NDE (Non-destructive Examination) of welded piping fabricated from aluminium. It is provided to the Vendor for the specification and definition of the Contractor’s minimum requirements for the Work.

Any references to Vendor define the requirements to be imposed on the Vendor by the Contractor.

E2. DEFINITIONS AND ABBREVIATIONS

It shall be the Vendor’s responsibility to comply with the requirements of all Specifications, Codes and Standards which are applicable to this Specification.

In addition to the specifications stated in Section 2, the following specification also forms a part of the specification:

American Welding Society (AWS)

AWS A5.10-99 Aluminium and Aluminium Alloy Bare Welding Rods and Electrodes

E3. QUALIFICATION OF WELDING PROCEDURES AND WELDERS

E3.1 Welding Procedures

E3.1.1 All welding procedures shall be in writing and shall be qualified in accordance with the ASME Boiler and Pressure Vessel Code, Section IX, Project Specifications & S-000-1351-0004V as in effect prior to date of purchase order for equipment being fabricated

< Relevant requirements of 3550-8440-SP-0018 are already includes in this specification >

E3.1.2 Welding procedures, qualification records and weld maps for welding the equipment in accordance with this Appendix Specification shall be submitted for review and permission to proceed prior to commencing fabrication. Welding procedures and qualification records shall be submitted on forms similar to Forms QW-482 and QW-483 as shown in the ASME Code, Section IX and project specification S-000-1351-0004V. Welding procedures that have not been previously reviewed and approved for this project shall be submitted as soon as possible after award of work and sufficiently ahead of actual welding to allow for adequate review and Approval.

E3.1.3 All welding procedures shall be identified by number and shall be referenced on all fabrication drawings.

E3.1.4 The welding procedure tests shall demonstrate that all details are satisfactory for obtaining full penetration welds for the following types of joints:

a) Double-welded longitudinal and circumferential butt joints.

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b) Single-welded circumferential and longitudinal butt joints made without a backing ring or strip.

E3.1.5 For inert gas tungsten arc and inert gas metal arc, the Welding Procedure shall include the composition and flow rate of inert gas backing when used.

E3.1.6 For GMAW (gas metal arc welding), power source inductance setting, electrode diameter and travel speed shall be addressed in the Welding Procedure in addition to the essential variables required per ASME section IX.

E3.1.7 For GTAW welding with square wave AC power source, use either pure tungsten or zirconiated electrodes with a ball shape tip.

E3.1.8 Except for piping, the gas metal arc process shall employ starting tabs in all groove welding.

E3.1.9 For all processes, the welding procedure shall contain a detailed cleaning procedure, indicating joint preparation prior to welding.

E3.2 Welders and Welding Operators

Welders and welding operators shall be qualified in accordance with ASME, Section IX, prior to fabrication; records shall be available upon request.

E4. MATERIALS

E4.1 Base Metals

5xxx and 6xxx series aluminium alloys shall be used for all welded fabrications.

Temper condition of alloy used may be up to, but not including, ASTM T6/H34.

E4.2 Filler Materials

E4.2.1 Welding products shall be used within the limits recommended by their manufacturers.

E4.2.2 Electrodes and rods shall be kept clean, dry and properly stored according to manufacturer’s recommendation. No electrodes or rods that are damp, greasy or oxidised may be used.

E4.2.3 Filler metal for similar and dissimilar base metal combinations shall be per the Table 1 of AWS Specification A5.10-99, unless Contractor Approval is obtained for alternate consumables.

E5. JOINT PREPARATION, SPACING AND ALIGNMENT

E5.1 Edge Preparation

E5.1.1 Weld bevels shall be suitable for the welding process to be used; the contour shall permit complete fusion throughout the joint. Bevels shall be in conformance with joint details as accepted by ASME or AWS welding codes.

E5.1.2 Weld bevels shall be made by machining, grinding or cutting and the surfaces shall be reasonably smooth and true.

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E5.2 Cleaning

Surfaces to be welded shall be clean and free from paint, oil, dirt, scale, oxides and other material detrimental to welding. Cleaning shall be done in a manner that will not lead to contamination of the weld or adjoining base metal. Weld edge cleanliness is very important for radiographic quality in aluminium alloys. The oxide from the surface to be joined must be removed prior to welding by appropriate chemical or mechanical methods. Suitable mechanical methods wire brushing, filing, scrubbing with steel wool or scraping. Welding should follow immediately after the cleaning operation. Grinding shall not be used for cleaning surfaces that are to be welded.

E5.3 Butt Joints

E5.3.1 The root gap and offset of butted edges shall be as required by the applicable ASME Code and as used in the procedure qualification. Joint design in single-welded butt joints shall be such that full penetration can be attained.

E5.3.2 Double-welded joints shall be suitably prepared for back welding to allow complete penetration and fusion.

E5.3.3 The use of permanent backing rings shall be subject to prior written Approval only. If permanent backing rings are permitted, the upstream edge shall be continuously seal welded.

E6. WELDING PROCESSES & TECHNIQUES

E6.1 All welds shall be made by the GTAW process, with filler metal addition, or the GMAW process.

E6.2 Inert gas backing (purge) using either Argon or Helium is required for all single-welded full penetration joints.

E6.3 All welding processes shall be protected from wind, rain and other harmful weather conditions which may affect weld quality. All surfaces to be welded shall be visually inspected. They shall contain no laminations or other injurious defects.

E6.4 Welding techniques shall be selected to ensure that specified tolerances for out of roundness are not exceeded. If such tolerances are not stated in the drawings, standards or specifications, the applicable section of the relevant code shall govern.

E6.5 Welded joints shall be made by completing each weld layer before succeeding layers are deposited

E7. WELD CONTOUR AND FINISH

E7.1 Weld beads shall be contoured to permit complete fusion at the sides of the bevel and to minimise inclusions. Oxidation shall be completely removed from weld beads and from the surface of completed welds and adjoining base material. The oxide removal shall be done in a manner that will not contaminate or overheat the weld or adjoining base material.

E7.2 Weld reinforcement, undercut and finish shall be as required by the applicable code.

E7.3 Weld bevels and weld surfaces shall be free of cracks, excessive porosity, inclusions and other defects indicative of poor workmanship.

E7.4 Welds that are to be examined by non-destructive methods shall be finished as required by the applicable standards listed in Table E1.

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E7.5 Peening shall not be permitted.

E8. NDE (NON-DESTRUCTIVE) EXAMINATION

E8.1 Examination

Minimum examination of welds shall conform to procedures and acceptance standards outlined in Table E1.

E8.2 Extent of Examination

Unless additional examination is specified in the Project Specifications, or Data Sheets, minimum examination shall be as follows:

(i) All welds shall be visually examined after completion.

(ii) Liquid penetrant examination may be substituted with Contractor Approval when radiography is

difficult to interpret. Internal surfaces shall be examined where accessible.

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TABLE E 1

WELD EXAMINATION PROCEDURES AND ACCEPTABLE STANDARDS

Method Specification or Standard Notes

Complete Radiography

ASME Section VIII, Par. UW 51.

ASME B31.3, Chapter VI, (Piping Only)

(1)

Random Radiography

ASME Section VIII, Par. UW 52.

ANSI B31.2, Par. 336.4.5,

(Piping Only)

(1)

Liquid Penetrant ASME Section VIII, Appendix 8

Ultrasonic

ASME Section VIII, Appendix 12

NOTES:

1) Additional requirements for radiographic examination are:

Fine grain film shall be used, Kodak AA or equivalent. Only lead screens may be used. (NOTE 1 cont.) Contractor Approval is required for use of penetrameters other than those specified in ASME Section VIII. Approval will be based on the thickness and hole sensitivity equivalent to that required by ASME Section VIII on sample radiographs of thicknesses containing both the ASME and the proposed penetrameter. Single-film viewing shall be used and the film density shall be in the range of 1.8 - 4.0 for an x-ray source and 2.0 to 4.0 for a gamma-ray source. For those instances where the variable thickness makes single-film viewing impracticable, double-film viewing may be used with the Inspector's concurrence. For the double-film technique, the maximum film density shall be 4.0 for double-film combination with a minimum density of 1.8 for each individual film. Radiograph of welds in pipe having a nominal diameter of 3" or less may be performed by the elliptical projection technique. At least two separate exposures are required at locations 90° apart. Where there is no internal access, radiographs of welds in pipe having a nominal diameter greater than 3" shall be such that at least three separate radiographs are taken 120° apart. Only that portion of the weld on the film side of the pipe (opposite the radiation source side) shall be interpreted. Because of the variation in pipe diameter, wall thickness and source-to-film distance, it may be necessary to take more than the minimum number of radiographs to properly examine the entire circumference of a weld.

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E8.3 Where random non-destructive examination is specified (i.e., a percentage of each welder's welds or a percentage of total welding) and shows welds failing to meet code or specification requirements, examination shall be made of two or more welds made by the same welder. If either of the additional welds are unsatisfactory, the Contractor’s Inspector may reject all work by that welder. Costs of examinations and repairs to defective or rejected work shall be at the Vendor’s expense.

E8.4 Cleanliness shall be maintained after completion of welding. All stubs, rods, flux, slag and foreign material shall be removed from the piping.

E9 REJECTION

E9.1 The applicable codes and Project Specifications specify defects which are cause for rejection. E9.2 When a welder's or welding operator's welding is judged unsatisfactory by a Contractor’s

Inspector, he shall be removed from the job by the Vendor. All of the welder's or operator's weld shall be examined by non-destructive examination and removed or repaired as directed by the Contractor’s Inspector. The welder or welding operator may be reassigned only after additional training, the completion of satisfactory qualification tests, and with the Approval of the Contractor’s Inspector.

27 SUPPLIMENTAL REQUIREMENTS FOR LICENSORS

In addition to the requirements through Paragraph 1 to Paragraph 26, the supplemental requirements for licensors specified in ATTACHMENT-A shall be complied with. Those requirements shall take precedence over the requirements in Paragraph 1 to Paragraph 26.

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28 ATTACHMENT-A: TECHNICAL REQUIREMENTS BY CLG

A Pipe and piping components that have “Licensor-2” in Purchaser’s Description shall comply with all the requirements in this attachment, Attachment-A, in addition to the requirements through Paragraph 1 to Paragraph 26.

A.1 Ferrite Content

For Austenitic stainless steel welds not subject to stress relief and operating temperature is 500 deg.C or less:

Ferrite content shall be mentioned in PQR. The ferrite content shall be limited to 3 to 10%. Additional test record of ferrite check can be attached to the PQR.

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