Piping Welding General Specification Consortium) Rev-3

OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY

AROMATICS COMPLEX PROJECT AROMATICS PLANT

CONTRACTOR ID. CODE

3282-XH-SW-T004

Contract No. KARO/1/2005

TCM Job No. : 3282 SKEC Job No. : 06025D

Location: Shuaiba, Kuwait Sheet 2 of 48 Rev. 03

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CONTENTS 1 GENERAL PROVISIONS ...................................................................................................... 3 2 BASE MATERIALS ................................................................................................................ 4 3 WELDING PROCESSES....................................................................................................... 5 4 WELD MATERIALS (FILLER METALS).............................................................................. 7 5 BACKING GAS PROTECTION .......................................................................................... 11 6 WELDERS............................................................................................................................ 11 7 LOCATION OF WELDED JOINTS .................................................................................... 12 8 PREPARATION OF EDGES AND TACK WELDING............................................................ 12 9 PREHEATING ...................................................................................................................... 14 10 WELD EXECUTION.......................................................................................................... 14 11 HEAT TREATMENT ......................................................................................................... 19 12 HARDNESS TESTS......................................................................................................... 20 13 P.M.I.................................................................................................................................. 21 14 WELD EXAMINATION AND INSPECTION.................................................................... 21 15 CERTIFICATIONS ............................................................................................................ 24 16 WELDING OF PIPING SUPPORT .................................................................................... 25

ATTACHMENTS: Fig. 1 – Drying procedure Fig. 2/3 – Distance between joints Annex 1 – table 330.1.1 ASME B 31.3 Preheat temperature Annex 1a – para 131 ASME B 31.1 Preheat temperature Annex 2 – table 331.1.1 ASME B 31.3 Post Weld Heat Treatment temperature Annex 2a – table 132 ASME B 31.1 Postweld Heat Treatment temperature Annex 3 – welding & NDE summary list Annex 4 – edges preparation Annex 5 – fig. 328.4.4., 328.5.2A/B/C, 328.5.4A/B/C/D, 328.5.4E, 328.5.5 of ASME B 31.3 Annex 5a– fig. 127.4.4, 127.4.8 Annex 6 – buttwelding ends ASME B16.25 Annex 7 – figure for hardness Table 1 – Summary for field welding book preparation

LIST OF APPLICABLE STANDARDS ASME IX ASME B 31.1 - ASME B 31.3 ASME B 16.25 ASNT TC 1A F 49.1 SFA 5.11 SFA5.1 SFA 5.14 SFA 5.4 SFA 5.17 SFA 5.5 SFA 5.18 SFA 5.9 SFA 5.28 AWS D1.1

OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




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1 GENERAL PROVISIONS

1.1 This specification applies to the welding of girth joints on piping made of carbon steel, low temperature carbon steel, low alloy and stainless steel. In particular, the specification covers butt joints of pipes, fittings, flanges and valves, branching and socket joints throughout pipelines or in the points of connection to equipment.

Such girth welds are both shop and field executable prior to erection or on erected piping.

It should be recognized that this specification provides general recommendation and requirements applicable to the generality of the scope of work and is not meant to cover all and every case. Designers are therefore urged to verify the applicability of such recommendations and requirements to their case. This specification applies also for welded connections from instrumentation and piping lines. For this purpose since AISI 316 can often be used instead of AISI 304 for instrumentation components, for AISI 316 shall be employed the same welding procedure and filler metal as those selected for AISI 304. This specification shall be applied also for welded joints of support to piping lines, if any (see par. 16)

1.2 Terms used in this specification mean the following:

Owner is referred to K.P.P.C. or his representative (third party) Contractor is referred to TCM/SK Consortium or to Company referenced in the purchase order Vendor or Manufacturer is referred to item supplier or manufacturer Fabricator is referred to the company entrusted for plant erection. Examiner is referred to the personnel of the fabricator that performing Quality control examinations. Inspector is referred to Contractor’s and/or Owner’s inspector or Statutory Agency inspector.

1.3 With reference to the execution and control of welds as provided for under par. 1.1. above, the specification is based on criteria of ASME Std. B31.3, last edition the said Standard to be briefly referred to hereinafter as ASME B 31.3 and ASME B 31.1 for boiler piping (piping classes ASME B2, ASME B4 and ASME E4). Requirements of this specification are also in compliance with the following project specifications: KA8S-6500-01, 02 and 03.

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




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The Consortium of

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1.4 Every discrepancies shall be highlighted in writing to TCM for clarification.

1.5 Should any of the provisions of this specification be deemed to be in contrast with his criteria or his own experience, the Fabricator shall previously notify owner of any such discrepancies for due clarification.

1.6 Derogations or modifications, if any, required by the Fabricator shall obtain a previous written consent from owner.

1.7 References made in this specification to ASME code B 31.1 are to be intended applicable only to piping classes ASME B2, ASME B4 and ASME E4.

2 BASE MATERIALS

This specification covers, the following base materials : - Carbon steel Galvanized (P-Number 1, in conformity with ASME B 31.3)

PIPING CLASSES: DE03, PU32, PU80, PU86 - Carbon steel (P-Number 1, in conformity with ASME B 31.3)

PIPING CLASSES: HC35, PU02, PU04, PU34, PU41, PU51, B1A2BD, B1A2BZ, B1A2LT, B1A2NN, B2A2BZ, B2A2LT, B2A2NN, B4A2NN

- Carbon steel (P-Number 1, in conformity with ASME B 31.1) PIPING CLASS: ASME B2, ASMEB4

- Carbon steel in AMINE service (P-Number 1, in conformity with ASME B 31.3) PIPING CLASS: B1A2AM

- Killed Carbon steel for sour service NACE (P-Number 1, in conformity with ASME B 31.3) PIPING CLASSES: ES12, ES13, C1A2BD, C1A2SO, C1A4SO

- Carbon steel in HYDROGEN H2 service (P-Number 1, in conformity with ASME B 31.3)

PIPING CLASSES: B1E2HY, B2E2HY, B4E2HY

- Carbon steel for sour service NACE + HYDROGEN H2 service (P-Number 1, in conformity with ASME B 31.3) PIPING CLASSES:, C1E2SO, C2A2SO, C2E2SO, C2E4SO, C4E2SO

- Low Temperature carbon steel - 45 °C (P-Number 1, in conformity with ASME B31.3) PIPING CLASSES: T1A2RT, T2A2RT

- Low alloy steel 1.25Cr 0.5Mo (P-Number 4 in conformity with ASME B 31.1) PIPING

CLASSES: ASMEE4 - Low alloy steel 1.25Cr 0.5Mo in HYDROGEN H2 service (P-Number 4 in conformity with

ASME B 31.3) PIPING CLASSES: E2E1HY, E2E2HY, E4E2HY

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

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- Austenitic stainless steel AISI 304 Carbon controlled/modified in the range of 0.04÷0.08%(P-Number 8 in conformity with ASME B 31.3) PIPING CLASSES: PR-33, PR-43S

- Austenitic stainless steel AISI 304/304L dual grade (P-Number 8 in conformity with ASME

B 31.3) PIPING CLASS: DE56, PU09, PU11 - Austenitic stainless steel AISI 316/316L dual grade (P-Number 8 in conformity with ASME

B 31.3) PIPING CLASSES: M1A0AM, M1A0NN, M2A0NN, M4A0NN - Austenitic stainless steel AISI 316/316L dual grade in HYDROGEN H2 service (P-Number

8 in conformity with ASME B 31.3) PIPING CLASSES: M2E0HY, M4E0HY

3 WELDING PROCESSES

The following welding processes are permitted:

- manual shielded metal arc welding (SMAW); - manual and automatic inert gas tungsten arc welding with unmeltable electrode

(GTAW); - automatic submerged arc welding (SAW); - automatic gas metal arc welding (GMAW – spray or globular transfer mode); - flux cored arc welding FCAW for PNo-1 steels with an external shielding gas. This

process is not permitted for root pass in one side welded joints, and for low temperature applications.

- a combination of the above processes. Other welding processes can be used provided that proper agreement is obtained from owner. The limits of applicability of the single processes for each piping class are defined at para 31. to 3.3 and summarized in table 1. Welding procedure specifications (WPS) and procedure qualification records (PQR) shall be made available by the fabricator for Owner's inspectors review and approval. All WPS and PQR shall be collected by Mechanical Erector in a Welding Book through Form nº140 (see table 2) and shall be submitted to TCM/SK Consortium Dept. for approval. No welding shall be done before approval of WPS/PQR. SMAW, SAW shall not be used for root pass unless the slag can be removed from the root pass side and the area inspected.

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3.1 Manual Shielded Metal Arc Welding (SMAW)

The use of cellulose or basic coated (i.e. with a low hydrogen content) electrodes is permitted with the following limitations :

3.1.1 Cellulose Coated Electrodes.

These electrodes may be employed for the execution of the root and second pass (both not exceeding) 6 mm of non back welded full penetration joints, limited to carbon steel and to thickness not exceeding 15 mm. The use of cellulose coated electrodes is not permitted for the execution of the root pass of carbon steel joints having an out-side diameter below 50 mm and a thickness below 4 mm. Such electrodes may be used for the execution of subsequent passes, limited to thickness equal to or lower than 6 mm.

Reconditioning of Cellulosic electrodes is prohibited.

For low temperature carbon steel the use of cellulosic coated electrodes is not permitted.

3.1.2 Basic Coated Electrodes (i.e. with a low hydrogen content).

In socket joints these electrodes may be employed without limitation. In full penetration joints they may be used with all steels for the execution of filling passes once the root pass has been performed. The use of basic coated electrodes is not permitted for the execution of the root pass of non back welded joints but it is permitted for the execution of the root pass of back welded joints.

3.1.3 The backing gas protection shall be performed as provided for under par. 5.

3.2 Manual and automatic inert gas tungsten arc welding (GTAW)

This process may be employed for the execution of the root pass of non back welded full penetration joints with all steels. The process may be used also for the execution of subsequent filling passes for joints. Backing gas protection shall be performed as provided for under par. 5.

3.3 Automatic submerged arc welding and automatic gas metal arc welding (SAW and GMAW/FCAW)

These processes may be employed for the execution of filling passes, limited to butt and socket girth joints with rotating horizontal axis, having an outside diameter equal to or higher than 150 mm and a thickness exceeding 5 mm. The multipass technique shall be adopted in the case of the SAW process. For SAW process, maximum weld deposit per pass shall be 13mm for carbon steel (P-No.1) and 10mm for all other materials Backing gas protection at the weld back shall be performed as provided for under par. 5.

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

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3.4 Qualification of process

Welding process shall be qualified in conformity with ASME B31.3, para 328.2. For low temperature carbon steel with design temperature below –29ºC, upon qualification of the process, impact tests shall be performed in compliance with the provision of ASME B31.3 (par. 323.2.2 and par. 323.3) as listed below:

Welding procedure qualification (PQR) for low temperature carbon steel piping classes: T1A2RT, T2A2RT shall include impact test at –45ºC. PQR shall be made with base and welding material belonging to supply in order to satisfy also the requirements for production welding tests of ASME B31.3 para 323.3 and tables 323.2.2 and 323.3.1. For welding procedure qualification (PQR) of piping classes in NACE, NACE + Hydrogen, Hydrogen services (see para 2)additional requirements are indicated in para. 10.19 to 10.22.

4 WELD MATERIALS (FILLER METALS)

The Fabricator may select weld materials (electrodes, rods, wires, fluxes) among the commercial types available. The materials selected shall however comply with the provisions of ASME B31.3, par. 328.3 or ASME B31.1 par. 127.2 as well as with those under par. 4.1. trough 4.6. For piping classes for special corrosive service additional requirements for welding consumables are specified in paras 10.19 to 10.23. For piping classes in H2 service B1E2HY, B2E2HY, B4E2HY only carbon steel consumables type ER 70x or E 7018.x/7016x (i.e not alloyed with nickel content) shall be used in order to obtain weld hardness lower than 200HB. At the time of use, the filler metals shall be in good state and not exhibit traces of rust, oil, grease, paint, varnish or lacquer, earth or any other matter liable to compromise weld soundness. Electrodes, rods and wires shall also be duly marked to prevent possible confu-sion. Recommended weld materials are listed in table A. Attention shall be paid during fabrication activities to keep well segregated and duly identified the welding consumables for piping made of 304 carbon controlled/modified (PR-33 and PR-43S). Consumables will be stored in appropriate location, release will be controlled through a bill by authorized personnel to qualified and certified welders.

4.1 Weld materials for homogeneous joints

As regards carbon steel homogeneous joints the weld material shall have mechanical properties not lower than the base metal. Insofar as concerns homogeneous low alloy and stainless steel joints, the weld material shall have mechanical properties not lower than the base metal and a corresponding chemical composition for main elements.

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




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4.2 Weld materials for diisimilar joints between stainless steel, carbon or ferritic steel shall be evaluated case by case by Engineering

For joints between carbon steels having different mechanical properties (minimum tabular values), weld materials ensuring a deposited metal strength not lower than the one of the lowest strength base metal shall be employed. Possible heterogeneous joints between ferritic steel and austenitic stainless steels will be normally executed by employing nickel based weld materials corresponding to : - ERNiCr 3 (SFA - 5.14.) - ENiCrFe 3 (SFA - 5.11.) - ENiCrFe 2 (SFA - 5.11.) In particular cases, weld materials of stainless steel type 309, 309Mo 310 and 310 Mo may be used provided prior authorization is obtained from the Owner's inspector. Heterogeneous joints between different grades of austenitic stainless steels shall be performed according to the Table A (filler metals are designated as AWS standards).

TABLE A Base metals

304L 309 309S 310 310S 316 316H

316L 317 321 321H

347,347H 348,348H

304 304**

308 308L*

308 309

308 309

308 309* 310

308 309* 310

308 316*

308 316

316L*

308 316* 317

308 308

304L 308 309*

308 309*

308 309* 310

308 309* 310

308 316

308 316L*

308 316* 317

308L* 347

308L* 347

309 309 309* 310

309* 310

309 316L*

309* 316

309* 347

309* 347

309S 309* 310

309L* 310

309* 316

316L 309L*

309 316

309* 347

309* 347

310 310 316 316Mo* 310Mo

316 316Mo* 310Mo

317 309Mo* 310Mo

308 310*

308 310*

310S 316 316Mo* 310Mo

316 316Mo* 310Mo

317 309Mo* 310Mo

308 310*

308 310*

316 316H

316 317 316*

308 316*

308 316* 347

316L 317 316L 316L* 347

317 308 317*

308 317* 347

321 321H

308L* 347

*- Recommended filler material ** - Carbon controlled in the range of 0.04÷0.08%

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CONTRACTOR ID. CODE

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4.3 Coated electrodes

Coated electrodes to be employed for welding of carbon steel shall have characteristics conforming to the provisions of SFA 5.1. types E6010 (cellulosic), E 7016,E7016.1 (Low hydrogen type H4), E 7018 and E7018.1. Coated electrodes to be employed for welding of austenitic stainless steels shall have characteristics conforming to the provisions of SFA 5.4. type E308/308L/316/316L. Coated electrodes for nickel alloy deposits for eterogeneous joints shall have characteristics conforming to the provisions of SFA 5.11. type selected as per par. 4.2. Caution: low hydrogen electrodes have to be stored in a clean and dry area at room temperature. The electrodes brought out directly from intact packing should be used without rebaking.

Electrodes Manufacturer recommendation for redrying and holding shall be followed, in case of these recommendation are not available, please follow the below mentioned procedure.

Electrodes shall be stored in a controlled and conditioned location with : 20-45ºC at 50% RH before opening for carbon steel electrodes. 5-50ºC at 50% RH before opening for stainless steel electrodes.

The remaining electrodes can be conserved in a oven at 120-175ºC for carbon steel and duplex stainless steel and 65-90ºC for stainless steel and nickel base. The electrodes not conserved in a oven and that are in packing not intact shall be previously dried in a oven at a temperature between 320°C and 350°C (for electrodes of carbon steel) and between 200ºC and 270 °C (for electrodes of austenitic stainless steel and nickel alloy) for two hours and there-after kept in a oven at 120-150°C, until the time of use. During welding operation the electrodes shall be conserved in portable ovens at a temperature of 100 °C at least. Holding ovens should be operated 24 hours to avoid redrying and in case of redrying the information should be recorded in the redrying register maintained by sub-contractor, the rebacking can be made maximum three times and to be monitored by the authorized personnel (see para 4 last sentences). Any possible power interruption should be recorded with by sub-contractor by appropriate tools. A general indicative drying procedure for low hydrogen electrodes of carbon steel is given in figure 1.

Specially coated (having a high nickel content) electrodes will be treated according to manufacturer's instructions unless supplied in sealed containers.

Reconditioning of Cellulosic electrodes is not permitted, these electrodes shall be stored in a controlled location with 20-45ºC at 50% RH before opening.

Coated electrodes for impact tested carbon steel shall have impact test guaranteed by relevant AWS standard at a temperature not warmer than impact test temperature specified for piping components to be welded. Welding procedure qualifications (PQR) involving low temperature carbon steel shall be carried out using covered electrodes belonging to the supply. For welding of 304Carbon controlled/modified piping classes as per para 2, electrodes shall be in accordance to SFA 5.4 type E308H with 0.04÷0.08% carbon content range.

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

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4.4 Rods and wires for manual and automatic inert gas tungsten arc welding (GTAW)

Rods and wires to be employed for GTAW process shall be supplied by the manufacturer specifically for the purpose. Rods and wires to be employed for the welding of carbon steels shall have characteristics conforming to the provisions of SFA - 5.18. type ER 70S2, S3 or S6. Rods and wires to be employed for the welding of austenitic stainless steels shall have characteristics conforming to the provisions of SFA 5.9 type ER 308/308L/316/316L. Rods and wires for nickel alloy deposit shall have characteristics conforming to the provisions of SFA - 5.14 (types shall be selected according to par. 4.2). Rods and wires for impact tested carbon steel shall have impact test guaranteed by the relevant AWS standard at temperature not warmer than impact test temperature specified for piping components to be welded. For welding of 304Carbon controlled/modified piping classes as per para 2, wire shall be in accordance to SFA 5.9 type ER308H with 0.04÷0.08% carbon content range. After removal from manufacturers packaging, wires shall be clearly identified at electrode ends. Appropriate color coding shall be provided by sub-contractor.

4.5 Wires and fluxes for automatic submerged arc welding (SAW)

Wires and fluxes to be employed for welding of carbon steels shall have characteristics conforming to the provisions of SFA 5.17. Wires and fluxes to be employed for welding of carbon steels shall be approved during the process qualification step. Wires and fluxes to be employed for the welding of austenitic stainless steels shall be approved during the process qualification step (wires shall conform to SFA 5.9). Fluxes shall be stored as specified by the Manufacturer; in any case drying is recommended with the method and at the temperatures as per low hydrogen electrodes. For rebacking, the fluxes shall be positioned in a oven in order to perform a bed with maximum height 30 mm. For SAW used for NACE piping classes the flux and wire used in production welding shall be the same brand name, type as that used in the qualification tests.

4.6 Wires for automatic gas metal arc welding (GMAW) or flux cored arc welding (FCAW)

Wires to be employed for the welding of carbon steels shall have characteristics conforming to the provisions of SFA 5.18. type ER 70S2, S3 or S6 or SFA 5.20 type E71T-1. Wires to be employed for welding of austenitic stainless steels AISI 304 shall have characteristics conforming to the provisions of SFA 5.9. type ER 308/308H/308L/316/316L. Nickel alloy wires shall have characteristics conforming to the provisions of SFA 5.14. (types to be selected according to par. 4.2.).

Rods and wires for impact tested carbon steel shall have impact test guaranteed by the relevant AWS standard at temperature not warmer than impact test temperature specified for piping components to be welded.

For welding of 304Carbon controlled/modified piping classes as per para 2, wire shall be in accordance to SFA 5.9 type ER308H with 0.04÷0.08% carbon content range.

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OWNER ID. CODE

KUWAIT PARAXYLENE

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5 BACKING GAS PROTECTION

In case of austenitic stainless steels, and in case of weld metal having high nickel content, inner gas protection shall always be provided during the execution of the root pass of non back welded full penetration joints. Backing gas protection shall be maintained at least until completion of the second pass and be provided also for outer socket welding in the case of thin walled pipes (with thickness equal to or lower than 4 mm). Backing gas is required also when supports are directly welded to stainless steel piping having thk of 4 mm and lower. According to the joint thickness, the welding process used and the size of the parts to be joined, backing gas protection may result necessary for the third pass too. Nitrogen, argon or helium may be employed for inner protection. However, nitrogen cannot be used in the case of weld materials having a high nickel content, Nitrogen is a acceptable alternative for Austenitic Stainless Steel when used for welding of external attachments. A backing gas protection is not necessary for welding carbon steel.

6 WELDERS

6.1 Qualification

Welders for manual and automatic procedures shall be qualified in conformity with ASME B31.3, par. 328.2.3 and par. 328.2.4 or ASME B 31.1 par. 127.5.2 and par. 127.5.3. Welder's performance qualification records shall be made available for Owner's inspector's review, upon request.

6.2 Identification

Qualified welders shall be identified by means of an exclusively assigned ID symbol which shall be stencilled at 20 mm from the weld bead, on both sides of the joint, prior to weld execution. Punching is not permitted on austenitic stainless steel. Paints free from Zn, Pb and halides will instead be used. In the case of joints executed by more than one welder, each welder shall stencil his own symbol to allow a clear identification of the joint portion executed by him.

6.3 Safety measures for the protection of welders and operators involved in welding and cutting shall be in accordance with the practices specified in the American National Standard F49.1.

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7 LOCATION OF WELDED JOINTS

7.1 In the case of two parallel girth joints, distance "d" between the weld axes shall not be smaller than 2.5 times the pipe weld thickness, with a minimum of 50 mm (see figure 2).

7.2 In butt welding of a pipe to a branch welded to a line, two cases are to be considered :

a) no heat treatment is to be conducted; b) heat treatment is to be conducted.

In case a), the joint distance from the line wall shall not be less than 2.5 times the pipe weld thickness, with a minimum of 50 mm. In case b), such distance shall not be less than 5 times the pipe weld thickness (with a minimum of 80 mm). This minimum distance may at any rate be reduced to 2.5 times the pipe weld thickness (with a minimum of 50 mm) if heat treatment of joint 2 is performed simultaneously with that of joint 1 (see figure 3).

8 PREPARATION OF EDGES AND TACK WELDING

8.1 Edge preparation shall preferably be made by machining. Automatic oxygen cutting followed by slight grinding is admitted for carbon steels.

Manual oxygen cutting may be conducted in exceptional cases only, followed by accurate grinding. Edges prepared by manual oxygen cutting, if any, shall be subjected to visual examination prior to assembly by QA/QC of Fabricator and by TCM/SK inspector at his own option. Edge preparation by oxygen cutting is not permitted for austenitic stainless steel, while for LTCS is permitted only if at least 3mm of base metal is ground off after oxygen cutting. Surfaces of P-No.4, 5, 6, 9, 10, 11, 5x and 6x materials that have been prepared with a oxyfuel gas torch shall have at least 4mm of additional material beyond the cut surface remove to eliminate any possible brittle zones.

8.2 In order to avoid confusion between similar materials, before any cut, the entire length of impact tested carbon steel components, Cr-Mo components, (i.e. flanges, elbows, pipes, tee, etc.) shall be marked in field with a strip of paint; as per spec. 3282 XZ SG 500.

Edge preparation for butt girth joints shall conform to the provisions of ASME for GTAW root pass (see ANNEX 4) and as indicated in the relevant WPS. The root gap for welding shall be as selected during the process qualification step. Edge preparation for branched connections and for socket joints shall conform to the provisions of ASME B 31.3 (see ANNEX 5) or ASME B 31.1 (see ANNEX 5a). The branch connection table is included in each piping class, Details for fit-up shall be indicated in a dedicated WPS. Preparations other than specified in the approved WPS’s are admitted provided due authorization is obtained from TCM/SK Consortium. Preparations shall in any case be such as to guarantee full penetration and to facilitate the execution of subsequent passes as well as the control of completed welds.

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The branch connection table is included in each piping class. Details for fit-up shall be indicated in a dedicated WPS.

8.3 The welding edges shall be free from fouling, rust, scales, grease, earth, paint, varnish or lacquer as well as from any possible local irregularities.

Besides on the bevel, thorough cleaning ought to be ensured on inner and outer pipe surfaces for an extension of 2x the wall thickness or 25mm whichever is less. When solvents sre deemed necessary by Fabricator or Inspector to complete cleaning for austenitic stainless steel piping, Sulphur and Halogen(Cl+) shall not be contained.

8.4 Pipe coupling will preferably be performed by means of mechanical couplers; however, the use of assembling brackets and U bolts welded to pipe walls is admitted.

If the material quality or the pipe wall thickness demand welding to be executed with preheating, the same preheating will be performed for the welding of U bolts. In the case of welds to be followed by heat treatment, the weld on assembling brackets shall be verified to be located within the area to be treated. The following electrodes will be utilized for the tacking of brackets and U bolts : - carbon and low alloy steel = carbon steel electrodes; - austenitic stainless steel = electrodes of stainless steel E 309 / E 309Mo. In joints to be back welded, pipe coupling may be conducted by executing tacking on the bevel bottom on the side opposite to the root pass. Generally, for non back welded joints, tacking on the bevel bottom shall instead be considered exceptional and shall be authorized on a case by case basis after examination of all details concerning the removal of tack deposits or the tack welding procedure in the case of tack deposits having to form an integral part of the welded joint.

For thin walled pipes (having a thickness equal to or lower than 2,5 mm) with joined square cut edge preparation, bevel tacking is recommended, while assembling brackets ought not to be used as pipe wall injuries would be liable to result from their application and removal. Special care shall be taken for U bolt removal to avoid pipe wall tearing. If tearing occurs, it shall be repaired after grinding to remove all surface defects or residues from the molten area.

Proper removal of defects shall be verified by means of penetrant liquids or magnetic particle examination. Repairs will be conducted by using the same electrodes as employed for the welding of butt joints, and preheating and heat treatment will be performed whenever required. On weld completion, followed by grinding to smoothness, a check with penetrant liquids or magnetic particle examination will be repeated to ascertain thorough removal of defects.

8.5 In case of uncorrect assembly of the components, the maximum permitted internal misalignment is:

3,2 mm or 25% of the material tickness whichever the minimum

When pipe bore don’t exactly match, the difference must be equally spaced over the circumference.

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8.6 Field bending of pipes is not permitted.

9 PREHEATING AND INTERPASS TEMPERATURE

Preheating of the ends to be welded shall be made before welding and during the execution of the joint in agreement with the criteria and procedures indicated by ASME B 31.3 par. 330. (See ANNEX 1) or ASME B 31.1 par. 131 (see ANNEX 1a). The temperatures specified for the various materials and thickness by the mentioned standards are the minimum values to be attained throughout an extension as wide as 6 times at least the thickness to be welded, located symmetrically astride of the joint, with a minimum of 25mm for each side. Preheating temperature shall be indicated in WPS. Preheating may be conducted by oxy-fuel gas torch with heating tip, air-fuel gas torch, electric resistance heaters or induction heaters. Preheating temperature shall be indicated in WPS. Electric resistance will be employed without limitation. Preheating required because of ambient conditions (temperature below 0°C) shall be performed by methods agreed upon in each particular circumstance. Preheating temperature control will be performed by means of thermometric colours and thermocouple. When the preheat temperature specified in the welding procedure is less than 50ºC, the material shall be heated until it is dry. When the required preheat temperature is 150 °C or higher, the metal temperature shall be maintained at preheat temperature until the weld is completed. The weld joint shall be wrapped with insulation and slow cooled. Interpass temperature shall be checked by welder during welding execution by thermometric colours, crayon indicator, optical pyrometer, etc.

10 WELD EXECUTION

10.1 If no preheating of the joint is required, the welder shall make sure the bevel and adjacent areas are dry.

In any case, if there is a high air moisture percentage, the pipes will be force heat dried at least in early morning hours. With an ambient temperature below 0 °C, preheating temperatures as provided in the above par. 9 shall in any case be applied for carbon steel. Unless welding is shop performed, proper sheds will be provided to protect the welding area against wind or other atmospheric agents.

10.2 No welds shall be executed on piping subject to shifting or vibrations (e.g. due to machinery connected thereto) to avoid cracks or ruptures. Whenever the use of meltable or unmeltable support rings is envisaged by the Fabricator for joint execution, proper prior authorization shall be obtained from Owner. Consumables insert are allowed only if duly authorized in

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KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




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The Consortium of

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writing by TCM/SK before production of welding. When inserts are permitted they shall be made from a material with the same nominal chemistry as the base metals being welded. Consumable inserts must be completely melted during welding.

10.3 Normally, arc ignition will be made using a proper plate, away from the joint. Arc ignition on the bevel is permitted with the GTAW process when employing a high frequency pilot spark device.

10.4 Inert gas protection within the pipe is provided for under par. 5.

10.5 The upward welding technique will be used for fixed horizontal axis joints.

10.6 The ends of weld lengths shall be removed by grinding at take-up points. Moreover, any weld length shall overlap at the start the adjacent executed weld length end to ensure proper joining of the various lengths. Any possible weld excess will be removed by grinding.

10.7 Surface oxide will be removed by brushing on completion of the first pass. A stainless material brush will be used for stainless steel. An accurate visual examination will also be performed to ascertain absence of cracks.

Any bead irregularities liable to cause defects in subsequent passes will be removed by grinding. The root pass shall exhibit a properly joined surface laterally along the bevel to permit the execution of subsequent passes without the danger of side inclusions. For scale removal of stainless steel se also par. 10.12. QA/QC field procedures shall include directives for welders to use proper tools suitable for stainless steel (i.e. colour coded tools).

10.8 The root pass shall exhibit a correct root penetration and be properly joined to the adjacent base material.

Full penetration of butt and branching joints is always required.

10.9 For the execution of the root pass with cellulose coated electrodes, an electrode diameter of 2.5 mm is recommended for pipe thickness equal to or below 8 mm and pipe diameters equal to or below 100 mm, also 3.2mm can be used.

10.10 In principle, the filling of joints shall follow the execution of the root passes immediately. No welding process may be discontinued before the joint thickness reach to 1/4 at least of the pipe wall thickness (and, in any case, to not less than 6 mm).

It follows that, in the case of pipes having a wall thickness lower than 6 mm, the welding process may not be discontinued until joint completion.

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




T

The Consortium of

&

10.11 In the case of weld executed with coated electrodes, joint filling shall be performed with electrodes having a diameter of 2.5 mm or 4.0 mm.

The use of electrodes having a diameter of 4 mm is permitted for joints welded on rotating horizontal axis pipes with wall thickness above 3 mm as well as for joints welded on fixed axis pipes having a diameter equal to or above 220 mm. Size of electrodes shall be indicated in WPS and maintained for production joints. Arc ignition will take place on the joint or on plates beside the joint. Possible arc strikes on pipe walls will be ground and smoothed surfaces will be examined visually and, possibly, by penetrant liquids or magnetic particle examinations.

10.12 Whenever completing any weld length, slags ought to be removed from the area to be covered by the subsequent weld length and the end crater should be removed by grinding. The latter operation shall always be conducted when defects appear on the crater.

Slags will accurately be eliminated on completion of any pass; stainless material brushes will be used for stainless steels. Single passes shall exhibit a sufficiently smooth surface and be properly joined to the bevel side walls. Whenever the surface of any pass exhibits irregularities or appears to be liable to bring about defects in subsequent passes, such irregularities shall be removed by grinding (special care will be taken in the elimination of undercuts as well as of slags between any two passes). In case the welding process is discontinued on reaching the specified thickness, special care shall be taken to ensure proper joining of the bead surface to the bevel walls prior to joint cooling.

10.13 On weld completion, the bead surface shall appear regular and properly joined to the adjacent base material.

The outer surface of beads will have a regular finish (obtained through grinding, if necessary) to avoid that surface irregularities may result in a difficult interpretation of any required non destructive examinations.

10.14 If allowed by accessibility conditions, joints will be back welded after accurate grooving to be closely examined prior to executing the back welding.

10.15 In the welding of austenitic stainless steels, interpass temperature shall not exceed 175 °C. For carbon steel, interpass temperature shall not exceed 300 °C.

10.16 Fillet and socket joints connections shall be executed in conformity with the provisions of ASME B 31.3, par. 328.4.2 and 328.5.2 (see ANNEX 5) or ASME B 31.1 par. 127.4.4 (see ANNEX 5a).

Socket joints shall be executed at least in two passes. Branch connections shall be executed according to ASME B 31.3 par. 328.4.2, 328.4.3 and 328.5.4 (see ANNEX 5) or ASME B 31.1 par. 127.4.8 (see ANNEX 5a).

10.17 Threading seal weld shall be performed for Piping Classes:ES12, ES13, HC35, PU02, PU04, PU09, PU11, PU41, PU51, ASMEB2, ASMEB4, ASMEE4, B1A2AM, B1A2BD,

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




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The Consortium of

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B1A2BZ, B1A2LT, B1A2NN, B2A2BZ, B2A2LT, B2A2NN, B4A2NN, C1A2BD, C1A2SO, C1A4SO, C2A2SO, C2E4SO, E4A2NN, M1A0AM, M1A0NN, M2A20NN, M4A0NN, PR33, PR 43S, T1A2RT, T2A2RT in such case all threaded shall be covered by weld metal.

10.18 When is necessary to weld galvanized materials, galvanizing coating shall be removed prior to welding on groove joints plus 25mm on base material (both sides), galvanizing coating shall be replaced in accordance to painting specifications.

10.19 Special requirements for steel piping lines in HYDROGEN H2 SERVICE (carbon steel classes B1E2HY, B2E2HY, B4E2HY and low alloy steel classes E2E1HY, E2E2HY, E4E2HY)

All butt welds in contact with process fluid shall be full penetration (GTAW process is required for root pass). Hardness test is required for all production butt joints on weld metal, the values for carbon steel shall not exceed 200HB. In case of hardness exceed the specified limits the PWHT is required. For low alloy steel, PWHT is always requested and HB shall not exceed 225. All socket welds (if any) shall be submitted to PWHT regardless of any hardness measurement. Additional PQR shall be performed with base and welding materials belonging to supply and hardness test on weld metal (WM) and heat affected zone (HAZ) as per annex 7 shall be provided. Maximum allowable HAZ hardness shall be ≤ 237HB/248HV and WM hardness shall be ≤ 200HB/210HV for carbon steel and ≤ 237HB/248HV - 225HB / 214HV for low alloy steel, PQR shall include both measurement of hardness by Brinell (HB) and Vickers (HV). Existing PQR are also acceptable provided that they are supplemented by additional hardness test carried out on separate test coupon.

Welding consumables for carbon steel piping shall be of type E/ER 70 and shall not contain alloying element such as Ni (to be less than 1%). Chemistry of welding materials shall be certified by Manufacturer through a material report type 3.1/3.1.b. Welded joints shall be radiographed as indicated by para 14.7, and as detailed in line list and isometrics (see also para 14 for other NDE tests).

Lack of fusion or severe under cuts are not accepted.

Welding of support to piping lines is not permitted. Special cases, when provided by applicable project specifications, shall be evaluated with Head Office.

Acceptance criteria are those specified by ASME B31.3 for severe cyclic condition.

10.20 Special requirements for carbon steel piping lines in SOUR SERVICE NACE (classes C1A2BD, C1A2SO, C1A4SO) and SOUR SERVICE + HYDROGEN H2 SERVICE(classes C1E2SO, C2A2SO, C2E2SO, C2E4SO, C4E2SO)

All butt welds in contact with process fluid shall be full penetration (GTAW process is required for root pass).

Hardness test is required for all production butt joints on weld metal, the values shall not exceed 200HB. In case of exceeding this value PWHT is required.

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




T

The Consortium of

&

Additionally, all socket welds (if any) shall be submitted to PWHT regardless of any hardness measurements..

Additional PQR shall be performed with base and welding materials belonging to supply and hardness test on weld metal (WM) and heat affected zone (HAZ) as per annex 7 shall be provided. Maximum allowable HAZ hardness shall be ≤ 237HB/248HV and WM hardness shall be 200HB/210HV for SOUR SERVICE + HYDROGEN and 237HB/248HV with average not exceeding 200HB/210HV for SOUR SERVICE, both hardness measurements by Brinell (HB) and Vickers (HV) shall be reported in PQR. Existing PQR are also acceptable provided that they are supplemented by additional hardness test carried out on separate test coupon.

Welding consumables for carbon steel piping shall be of type E/ER 70 and shall not contain alloying element such as Ni (to be less than 1%). Chemistry of welding materials shall be certified by Manufacturer through a material report type 3.1/3.1.b. All production butt joints shall be submitted to hardness test on W.M.. Hardness shall result not higher than 200HB. Welding of support to piping lines is not permitted. Special cases, when provided by applicable project specifications, shall be evaluated with Head Office.

Welded joints shall be radiographed as indicated by para 14.7, and as detailed in line list and isometrics (see also para 14 for other NDE tests). Acceptance criteria are those specified by ASME B31.3 for severe cyclic condition.


10.21 Special requirements for carbon steel piping lines in SOUR SERVICE NACE (classes ES12, ES13)

All butt welds in contact with process fluid shall be full penetration (GTAW process is required for root pass).

All joints shall be stress relieved (PWHT) regardless of thickness. Time and temperature of PWHT shall be as requested by ASME B 31.3, but not less than 1 hour and 620ºC respectively. Additional PQR shall be performed with base and welding materials belonging to supply and hardness test on weld metal (WM) and heat affected zone (HAZ) as per annex 7 shall be provided. Hardness shall be 237HB/248HV with average not exceeding 200HB/210HV for SOUR SERVICE, both hardness measurements by Brinell (HB) and Vickers (HV) shall be reported in PQR. Existing PQR are also acceptable provided that they are supplemented by additional hardness test carried out on separate test coupon.

Welding consumables for carbon steel piping shall be of type E/ER 70 and shall not contain alloying element such as Ni (to be less than 1%). Chemistry of welding materials shall be certified by Manufacturer through a material report type 3.1/3.1.b. All production butt joints shall be submitted to hardness test on W.M.. After PWHT hardness shall result not higher than 200HB.


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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




T

The Consortium of

&

Welded joints shall be radiographed as indicated by para 14.7, and as detailed in line list and isometrics (see also para 14 for other NDE tests). Acceptance criteria are those specified by ASME B31.3 for severe cyclic condition.


Welding is not permitted after Post Weld Heat Treatment.

10.22 Special requirements for piping when used in PAREX process unit (classes B1A2BD, B1A2NN, B2A2NN, HC35, M2A0NN, PU02, PU04, PU09, PU41, PU51 and PU86)

Root pass shall be made by using GTAW process to assure a residue free inside weld without mill scale, slag and coating or other foreign matter.

10.23 Special requirements for carbon steel piping in AMINE service (class B1A2AM)

All butt welds in contact with process fluid shall be full penetration (GTAW process is required for root pass). All carbon steel joints shall be stress relieved regardless of thickness, according to ASME B31.3. The holding time at temperature shall be not less than one hour. Welding consumables for carbon steel piping shall be of type E/ER 70 and shall not contain alloying element such as Ni (to be less than 1%). Chemistry of welding materials shall be certified by Manufacturer through a material report type 3.1/3.1.b.


Welded joints shall be radiographed as indicated by para 14.7, and as detailed in line list and isometrics (see also para 14 for other NDE tests).

Acceptance criteria are those specified by ASME B31.3 for severe cyclic condition.


Welding is not permitted after Post Weld Heat Treatment.

11 HEAT TREATMENT

11.1 The heat treatment after welding, is to be performed when required by the criteria indicated by ASME B31.3 par. 331. (see ANNEX 2) or ASME B 31.1 par.132 (see ANNEX 2a) and according to relevant PQR.

Additionally, Post Weld Heat Treatment is to be performed for piping lines in special corrosive service as specified in para 10.19 to 10.23. In the case of repair of defective joints by welding, heat treatment will be repeated. The thickness to be considered to estimate whether heat treatment is required as well as the heating time involved in the affirmative, will be the greatest thickness in the welded joint, taking into account the further provisions contained in ASME B 31.3, par. 331.1.3 or ASME B 31.1 par. 132.4.

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




T

The Consortium of

&

Starting from about 300 °C the heating rate shall not exceed 5.500/t °C/h (where "t" is the thickness of the welded parts quoted in mm) with a maximum of 200 °C/h. In the case of induction heating, the heating rate can be doubled. For localized heat treatments, the joint shall be cooled down slowly from the treatment temperature. It is recommended to reduce the cooling rate by covering the joint with insulating material (mineral wool) and cool it down in the air to a temperature of about 300 °C at which temperature the mineral fibre can be removed. In any case, for thicknesses exceeding 25 mm, the cooling rate (°C/h) shall be lower than 7.500/t (where "t" is the thickness quoted in mm) down to the temperature of about 300 °C. To estimate the heating and cooling rates involved, the greatest among the thicknesses of all parts subjected to heat treatment shall be considered, irrespective of whether they are located in the welded joint or not. Wherever PWHT is required for special corrosive service (i.e. at para 10.19 to 10.23), all thicknesses shall be subjected to heat treatment and the heating temperature will be the maximum value within the prescribed range (if not otherwise specified). In the case of induction heating for the joining of pipes, heating velocities may be double.

11.2 The heat treatment may take place within an oven or through heating of a pipe length including the welded joint (resistance or induction heaters).

The pipe length to be heated at the specified temperature shall correspond to 2 times at least the pipe wall thickness on both sides of the welded joint, with a minimum of 25 mm. The heat treatment shall be conducted by heating the entire joint uniformly. Temperature will be measured by means of thermocouple connected to recorder. In principle, temperature will be measured in 2 points at least for every joint, on the highest and on the lowest ones. Throughout heating, the maximum difference among the temperatures measured by the various thermocouple shall not exceed 60 °C. In steady state, the difference among the measurements performed by the various thermo-couple shall not exceed 30 °C. A recorded chart will be obtained for every heat treatment. Any deviation from this rule shall be previously authorized by the Customer in writing. No strict provisions are given insofar as concern heat treatment equipment. Proper equipment ought however to be made available such as to ensure reasonably uniform heating throughout pipe circumferences and thicknesses. Pipes ends shall be ascertained to be duly closed prior to performing any heat treatment, with a view to avoiding the occurrence of draughts within the pipe and the absence of external constraints liable to reduce the possibility of pipe axial expansions shall also be verified.

11.3 deleted

12 HARDNESS TESTS AFTER PWHT

In all cases where PWHT is required for reasons other than corrosive service, a minimum of 10% of welds in each heat treatment batch which are furnace heat treated, and 100% of those which are locally heat treated shall be hardness tested. The hardness limit applies to the weld and the heat affected zone.

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




T

The Consortium of

&

Hardness tests of production welds are intended as a check to determine if heat treatment has been performed satisfactorily. Hardness tests of the heat affected zone shall be made at a point as near as practicable to the edge of the weld. Brinell hardness shall not exceed 200 BHN for normal carbon steel, if not otherwise indicated in this specification. Brinell hardness shall not exceed 225 BHN for low alloy steel, if not otherwise indicated. For carbon and low alloy steel piping in special corrosive services see para 10.19 to 10.23. Hardness test shall comply with requirements of NACE RP 0472 standard.

13 P.M.I.

Positive Material Identification (P.M.I.) test shall be used to assure that specified alloy materials are properly supplied and installed PMI shall be performed on either base material as welded joints when required by project specification 3282 XZ SG 500.

14 WELD EXAMINATION AND INSPECTION

14.1 General

Weld examination and inspection shall be made in conformity with the provisions of ASME B 31.3, chapter VI and with the further provisions contained in paragraphs 14.3, 14.4, 14.5, 14.6 for piping classes ASME B4 and ASME E4 the code ASME B 31.1 chapter VI and with the further provisions contained in paragraph 136 shall be applied. A welding map will be maintained of pressure piping welds made on the plant selected for non destructive examination. The Welding Inspector shall verify that the Fabricator keeps a weld map with the above mentioned information constantly up to date (see a suggested welding map form in ANNEX 3). The QUALITY ASSURANCE Department of OWNER shall have the right to audit the Fabricator to verify that the requirements of this specification are complied with. Welds which are deposited by procedures other than those properly qualified and approved shall be rejected and completely removed. The acceptable value limits of examination and inspection test are those listed in ASME B 31.3 par. 341.3.2 (a) for severe cyclic conditions for welds required to be 100% radiographed or when requested in para 10.19, 10.20, 10.21 and 10.23, normal fluid service for other welds. Table 136.4.1 of ASME B 31.1 shall be applied for piping classes ASME B4 and ASME E4.

14.2 Qualification of NDT Personnel

Radiographic, ultrasonic, magnetic particle and liquid penetrant examinations shall be performed by operators qualified according to A.S.N.T. TC 1A Level II or equivalent.

14.3 Welding inspector

The WELDING INSPECTOR (WI) is entrusted to verify that all required examinations and testing have been completed and to inspect the piping to the extent necessary to be satisfied that it conforms to all applicable examination requirements of this specification.

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




T

The Consortium of

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The inspection performed by WI does not relieve the Fabricator of responsibility for providing materials, components and workmanship in accordance with requirements of this specifications, performing all required examinations and tests, preparing suitable records of examinations and tests for the welding inspector's use. The WI shall have access to any place where work concerned with the piping welding is being performed; this includes manufacture, fabrication, heat treatment, assembly, erection, examination and testing of the piping. He shall have the right to audit any examination method specified by this specification and to review all certifications and records necessary to satisfy the Owner's responsibility. The WI shall verify that all information about welds have been re-corded by the Fabricator on welding reports.

The WI shall be designated by the Owner or Contractor. The WI shall not represent nor be an employee of the Fabricator. The WI shall have a minimum of five years experience in the design, fabrication, or inspection of industrial pressure piping and he shall be qualified according to ASME B 31.3 par. 340.4 or to an equivalent standard.

14.4 Visual Examination

All welds shall be subjected to visual examination, according to the provisions contained in ASME B 31.3 par. 344.2. (or ASME B 31.1 par. 136.4.2 for piping classes ASME B4 and ASME E4) as well as to the following provisions. The Fabricator shall present welds accurately cleaned of any slag residue and brushed to remove the scale; in case of stainless steel, if brushing is not effective to remove the scale, the outside surface of welded joints shall be pickled and care at Fabricator charge). The bead outer surface shall be regular with regard to lattice, allowance height and joining to the base metal. Corner beads shall have dimensions as indicated in the relevant drawing. In the case of socket weld joints, the corner of the edge where the bead rests shall not have melted as much as possible.

14.5 Liquid Penetrant Examination

Liquid penetrant tests will be conducted in conformity with ASME B 31.3, par. 344.4 or ASME B 31.1 par. 16.4.4 and will be carried out on 10% of non radiographable joints and heterogeneous (butt or socket) joints: the extension will be increased up to 100% for non-radiographable joints on lines for which 100 % radiographic examination is specified. Non radiographable joints are considered the branching joints with NPS < 2", socket joints and joints of special components such as weldolets and coupling. See also examinations prescribed in table 1.

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




T

The Consortium of

&

14.5.1 Should tests conducted with penetrant liquids reveal the systematic presence of defects in welds or of defects imputable to misassembly and/or misremoval of assembling brackets, penetrant liquid testing shall be extended to 100% of welds. The extension of the test shall be at Fabricator's charge.

14.6 Magnetic particle Examination

Magnetic particle examination will be conducted in conformity with the provisions of ASME B 31.3 par. 344.3 or ASME B 31.1 par. 136.4.3. Magnetic particle examination may be required by WI to check the presence of possible cracks in the areas adjacent to the assembling brackets. Said examination may be replaced by penetrant liquid testing. See also examinations prescribed in table 1.

14.7 Radiographic Examination

The radiographic examination will be carried out according to provisions of ASME B 31.3 par. 344.5 or ASME B 31.1 par. 136.4.5. Radiographic examination will be performed with the extent required by radiographic classes indicated on isometrics and line list. If not otherwise specified, radiographic classes are represented by code letters A, B, C, etc, which define the percentage. Letter “5A” in line list = 5% Rx spot examination in accordance to ASME B 31.3 Letter “5B” in line list = 5% Rx random examination in accordance to ASME B 31.3 10% Rx examination 20% Rx examination 100% Rx examination The indicated radiographic percentage on Table 1 are the minimum required for related piping class higher percentage will be indicated in isometric and line list when deemed necessary on the basis of the criticallity of the service. This table shall be filled in by Fabricator with all data and submitted to inspector for approval. Required radiography shall be performed after PWHT. Exceptions will be evaluate case by case and approved in writing by TCM/SK Consortium, in such cases UT examination after PWHT are required (in addition to RT before PWHT).

14.7.1 Selection of joints to be radiographed When statistic examination is to be performed, the joints to be subjected to testing will be selected by WI in conformity with the following principles: a) Groups of homogeneous joints with regard to diameter and thickness will be considered separately. The specified percentage shall be radiographed for each group. b) The joints to be subjected to examination shall include weld of all welders with particular reference to the ones having supplied the lowest performances. c) Within the scope of every homogeneous group, the joints to be selected for radiographic examination shall include non back welded joints, those showing an irregular surface, those exhibiting a lower quality edge preparation or under conditions of low accessibility.

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




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The Consortium of

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d) The percentage of joints to be subjected to examination cannot be exhausted prior to the completion of all welds. For each homogeneous group the number of joints subjected to examination shall in no fabrication phase exceed the percentage provided for the joints executed. The maximum extent of defects revealed by radiographic inspection is indicated by ASME B 31.3 table 341.3.2. with the additional requirement of full penetration of the welds. If unacceptable defects are revealed, radiographic examination shall be extended to other joints according to the progression principles provided for by ASME B 31.3 under par. 341.3.4. Such additional radiographic examination shall be at Fabricator's charge.

14.7.2 X and Gamma ray selection 14.7.2.1 X-ray examination is admitted without limitation both on shop and field

executed joints. The use of gamma-ray will be admitted as an exception (in the case of impossibility to perform X-ray) previous comparison test respect to X-ray in order to maintain the same sensitivity and written consent from the Consortium.

Gamma-ray examination is admitted for field executed joints: however the thickness limitations as indicated for shop executes joints are recommended.

14.7.2.2 It shall be guaranteed by Fabricator (and verified by Welding Inspector) that the radiographic sensitivity level meet the requirements of ASME Sec.V Class 2-1T or 2-2T.

For wire penetrameter, the sensitivity shall be 2% as a minimum. 14.7.3 Films

Plates of type Gevaert D7, Kodak AA, Du Pont NDT.75 or similar film type will be employed for X-ray examination. Plates of type Gevaert D 4, kodak M, Du Pont NDT.55 or similar film will be employed for gamma-ray examination. The use of the same film type as envisaged for X-ray examination will however be admitted for gamma-ray examination with pipe thickness exceeding 40 mm.

15 CERTIFICATIONS

Fabricator will be required to keep record of all welders qualification results with full documentation of each welder working on project. This will include (but is not limited to) code recommended qualification records, reports indicating any defective welds and tests results for each welder. Up to date Welding Procedure Specification (WPS) and welding Procedure Qualification Records (PQR), in accordance with accepted specification, will be obtained for all welding works.

OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




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The Consortium of

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15.1 A welding map record will be maintained for all pressure piping welds indicating the type of weld, welder, material welding procedure, heat treatment (if any) and tests (see a suggested FORM in ANNEX 3).

The basic identification of all piping should be referenced to construction drawings (isometrics). Where isometrics are not available (i.e. piping having NPS below 2"), it will be made reference to Piping Routing or drawings or other maps suitable for such purpose. All information relating to a specific weld, including the radiographic examination, must be readily traceable.

15.2 All nondestructive examinations shall be certified by testing reports issued by Fabricator and signed also by W.I. when witness is performed.

16 WELDING OF PIPING SUPPORT

16.1 Welding of piping support to piping line, when they are permitted by design, shall meet the requirements of this specification, when applicable.

16.2 Welding to be performed for fabrication of supports shall meet the provisions of AWS D1.1 "STRUCTURAL WELDING CODE" or in accordance to ASME IX code.

16.3 Welding of support to piping lines, shall be performed by SMAW PROCESS (other process can be accepted) with covered electrodes. Covered electrodes shall be of type E 7016, E 7016.1, E7018, E7018.1 for carbon to carbon steel and type E 308L for stainless steel to stainless steel.

16.4 Dissimilar welding for pipe support directly attached to process pipe is not permitted under any circumstances. Particular cases shall be evaluated case by case by Engineering and necessary welding procedures shall be provided.

16.5 Preheating and stress relieving shall be provided if required for welded joints indicated in isometric. In case of Hydrogen (if any) PWHT for all fillet welds shall be provided.

16.6 For low alloy materials welded joints between supports and piping lines (i.e. reinforcing pad, pressure parts to no-pressure parts) shall be examined by 100% liquid penetrant tests.

Test method shall comply with requirements of par. 14.5 (acceptance criteria are those state by ASME B 31.3 par. 341.3.2.a for "NORMAL SERVICE CONDITION").

16.7 Welded joints used for fabrication of piping supports shall be examined by visual examination. If not otherwise required by support design specifications and drawings.

16.8 When the welding of support directly to stainless steel piping is permitted by TCM/SK Consortium design specification, backing gas protection is required at the inside of pipes having thk of 4 mm and lower, Nitrogen is a acceptable alternative for stainless steel.

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




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The Consortium of

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Figure 1 - Drying procedure

Drying procedure for ordinary low-hydrogen electrodes

packing not intact

torch

max 3 circulations

100°C to 120°C max 2 h

400°C to 420°C 2h

120°C to 150°C

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Figure 2/3 - distance between joints

d

fig.2

joint1 joint 2

joint 1

joint 2 d

fig.3

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Annex 1 – ASME B 31.3 Preheat temperature

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Annex 1a – ASME B 31.1 Preheat temperature

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Annex 2 – ASME B 31.3 Post Weld Heat Treatment temperature

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Annex 2a – ASME B 31.1 Post Weld Heat Treatment temperature

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Annex 3 – welding & NDE summary list

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Annex 4 – edges preparation

Edge preparation for prefabrication and erection of piping Edge preparation for butt welding shall conform to the provisions of ASME B 31.3 of para 328.4.2 or ASME B 31.1 para. 127.3 or applicable WPS. Component having nominal wall thickness of 3mm and less shall have square cut ends or slightly chamfered. In case of components having unequal thickness, the thicker end shall be tapered as shown in ANNEX 6.

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Annex 5 – fig. 328.4.4, 328.5.2A, 328.5.2B

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Annex 5 cont’d– fig. 328.5.2C, 328.5.4A/D

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Annex 5 cont’d– fig. 328.5.4E, 328.5.5

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Annex 5a – fig. 127.4.4, 127.4.8

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Annex 5a cont’d– fig. 127.4.8

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Annex 5a cont’d– fig. 127.4.8

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Annex 6 – buttwelding ends ASME B16.25

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Annex 7- figure for hardness tests

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Table 1 – Summary for field welding book preparation <2>

<3>

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The Consortium of

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Table 1 cont’d – Summary for field welding book preparation

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KUWAIT PARAXYLENE

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The Consortium of

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OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




T

The Consortium of

&


OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




T

The Consortium of

&


OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




T

The Consortium of

&


OWNER ID. CODE

KUWAIT PARAXYLENE

PRODUCTION COMPANY


CONTRACTOR ID. CODE

3282-XH-SW-T004




T

The Consortium of

&

Table 2

Documents

Piping Welding General Specification Consortium) Rev-3