006-ms for purging of stainless steel.pdf

Pearl GTL Project

LINDE ENGINEERING

Contractor Project No : 5887 Shell Project No: HP-3000-QAT

Project Document Number: T- 4.250.901 Project Rev.: A Page 2 of 17

Purchase Order Number: 2MH127

N/A Tag/Item Number(s):

ASU Unit(s):

Z PCWBS:

QATAR SHELL GTL PROJECT (PEARL) C2 AIR SEPARATION UNITS CONSTRUCTION

D A 21.04.2008 Ready For Construction BR UA ZG RFC

C O 23.12.2007 Issued for Company comments BR AU/MC ZG ICC

B 05.12.2007 Issued for Review BR AU/MC ZG IFR

A 22.11.2007 Issued for Internal Review BR AU/MC ZG IIR

Approved By

GAMA Project Rev Rev. Date Description

Prepared By

Checked By Status

No. No. ORIGINATOR

Document Title:

LINDE ENGINEERING AG

METHOD STATEMENT FOR PURGING OF STAINLESS STEEL

Document No.

GAM MTS MEC GTL 006 D LOC470

Contractor

Gama Qatar Co. W. L. L. Org.

Code Doc. Type

Disc. Code

Geogr. Area

Seq. No

Rev. No Vendor Code

Project Document Number: T-4.250.901 Rev No: A

Doc. Title : METHOD STATEMENT FOR PURGING OF STAINLESS STEEL

Doc. No. : GAM-MTS-MEC-GTL-006 Rev. D Date: 21.04.2008

T-4.250.901 Rev. A Page 4 of 17

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TABLE OF CONTENTS 1. SCOPE ________________________________________________________________________5 2. PURPOSE _____________________________________________________________________5 3. HSSE _________________________________________________________________________5 4. REFERENCE __________________________________________________________________5 5. DEFINITIONS _________________________________________________________________6 6. RESPONSIBILITY ______________________________________________________________7

Welding Supervisor __________________________________________________________________7 Welding Inspector____________________________________________________________________7

7. METHOD______________________________________________________________________7 Welding preparation__________________________________________________________________7 Purge dams types ____________________________________________________________________7 Purging_____________________________________________________________________________7 Measurement of gas flow rate __________________________________________________________8 Welding ____________________________________________________________________________8 Oxygen level measurement_____________________________________________________________9

8. INSTALLATION - CYLINDER METHOD ___________________________________________9 9. PROTECTION OF LARGE DIAMETER WELDS (NPS equal to or more than 14) ________10 10. CLOSURE WELDS ___________________________________________________________10 11. TGX WELDING______________________________________________________________10 12. SAFETY REQUIREMENTS____________________________________________________10 13. WITNESSING AND REPORTING ______________________________________________10 14. FIGURES___________________________________________________________________11 15. ATTACHMENT______________________________________________________________14



T-4.250.901 Rev. A Page 5 of 17

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1. SCOPE This method statement describes the modalities established by GAMA for gas backing protection of stainless steel piping butt welds for C2 ASU Pearl GTL Project.

2. PURPOSE Purpose of this Method Statement is to ensure that all gas backing protection activities are carried out correctly, with minimal risk of injury or damage.

3. HSSE All works shall be in compliance with the State of Qatar laws and regulations, Ras Laffan Industrial City and International standards, codes, LINDE ENGINEERING AG & QSGTL and/or its PMC requirements and instructions.

In addition all employees and GAMA subcontractor employees on site will have through LINDE ENGINEERING AG Site Safety Induction and GAMA Qatar Safety induction for site safety, health, environmental and security prior to work activities. Other training courses will be attended as required by LINDE ENGINEERING AG or QSGTL and/or its PMC as required.

4. REFERENCE ASME B31.3 Process Piping

AWS-D 10.4 Recommended Practice for Welding Austenitic Chromium Nickel Stainless Steel piping and Tubing

T-4.234.542 Project Quality Plan T-4.250.938 General Welding Procedure T-13.377.441 Quality Control Requirements of Welding DEP 30.10.60.31 Oxidation of Stainless Steel Weldments

T.4.250.931 Welding Consumable control DEP 30.10.60.18 Welding of metal (Amendments/supplements to API RP 582)

DEP 31.38.01.11 Piping - General Requirements DEP 31.38.01.31 Shop & Field Fabrication of Steel Piping Amendement T.13.376.796E



T-4.250.901 Rev. A Page 6 of 17

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T-4.250.938 General welding procedure T-4.250.939 Welders performance qualification T-4.250.920 ITP fabrication of Piping A/G & U/G

5. DEFINITIONS Company : QSGTL or its PMC Contractor : LINDE ENGINEERING AG Sub Contractor : GAMA QATAR Contract : QSGTL Pearl Plant - C2 ASU Project WSD : LINDEs (welding supervision & documentation system) ITP : Inspection and Test Plan QCP : Quality Control Procedure QCR : Quality Control Record WPS : Welding Procedure Specification PQR : Procedure Qualification Record WPQT : Welding Procedure Qualification Test NDT : Non Destructive Testing WQT : Welding Qualification Test GTAW : Gas Tungsten Arc Welding NDE : Non Destructive Examinations

WPS : Welding Procedure Specification GTAW : Gas Tungsten Arc Welding Ppm : Parts per million



T-4.250.901 Rev. A Page 7 of 17

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6. RESPONSIBILITY

WELDING SUPERVISOR The Welding Supervisor is responsible but not limited to: assure the correct observance of this procedure; assure the correct position of purge dams and the right purging time; assure the total removal of purge dams; Certify the purge dam installing and removing.

WELDING INSPECTOR

The Welding Inspector is responsible but not limited to: verify the correct observance of this procedure; Check the purity of gas as indicated in Para 7

7. METHOD

WELDING PREPARATION Welding preparation shall be made in accordance with GAMA General Welding Procedure (T-4.250.938) For diameter 3 and above, temporary tack welds shall be normally made on the groove with bridging. Bridging material shall be of same specification of the base material. For diameters equal to or less than 2, permanent tack welds in the root shall be made, according to the applicable WPS, using gas backing. In case that the tack welds on the root have been made without gas backing, they shall be removed by grinding and the ground area shall be checked with penetrant test.

PURGE DAMS TYPES The following types of purge dams can be used: soluble paper, when it can be removed by hand or by brushing, or blowing, or

flushing (where permitted), etc.; removable foam rubber plugs or internal rings, having an open section suitable

to be filled with gas, along the weld root (see details in the Para 9) Cylinder method (see details in the Para 8).

PURGING Argon 99.99% shall be used for backing purging. Before starting welding, an adequate purging shall be made in order to eliminate the oxidizing atmosphere inside the pipe.



T-4.250.901 Rev. A Page 8 of 17

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The operations for a proper purging are as follows: tape seal the weld joint; assure that the gas venting orifice has a flow capacity equal to or greater than

that of input side, for assurance of a near zero interior purge gas pressure (a purge gas pressure buildup during welding will result in excessive root bead concavity);

input argon at a flow rate of 24 liters per minute; minimum gas flowing time prior to commencing the welding/tacking to achieve

complete purging shall be as per the following table:

Midis

nimum purging time (minutes) according to the tance between purge dams (see notes 1 and 2) Nominal Pipe size 150 mm 300 mm 450 mm 600 mm

4 1 1 2 2 6 10 2 4 6 8 12 16 5 9 14 18 18 22 10 19 29 38 24 28 12 23 35 46 30 34 14 27 41 54

(*1) The above table has been calculated on the basis of AWS D10.4

Recommended Practices for Welding Austenitic Chromium Nickel Stainless Steel piping and Tubing.

(*2) For lengths more than 600 mm (for example, in case of closure welds where purge dams cannot be installed) refer to figure A.

MEASUREMENT OF GAS FLOW RATE All gas bottles shall be equipped with proper pressure gauges and flow meters, in order to allow the regulation of the pressure of gas and to check the actual flow rate.

WELDING After purging, and before starting welding operation (GTAW), the gas flow-rate shall be reduced to the value established in the applicable WPS. During welding, the seal-tape shall be removed just in advance of welding progression around the joint, in order to minimize purge gas loss and atmospheric contamination through the root opening. The backing gas purge shall be maintained until at least two layers of weld deposit have been made.



T-4.250.901 Rev. A Page 9 of 17

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OXYGEN LEVEL MEASUREMENT The permissible level of oxygen shall be less than 1%. Measurement shall be carried out by welding-gas oxygen analyzer SGI-2 (Dansensor) and shall be recorded in the purge dam tracking record. At the beginning of each method of protection, oxygen measurement shall be made on the first production joints having the following diameters, in order to confirm the minimum purging time established in the table shown in Para 7 (the reference distance between dams shall be 300 mm) and qualify the Argon gas protection/capability and arrangement. 4 10 16 22 28 32

When the values of the table have been confirmed, the times established in the table must be strictly observed by the Welding Supervisors or established time shall be maintained. The Welding Inspectors shall check on a random basis (minimum one joint every day) the oxygen level during surveillance of welding activities, using the calibrated instrument. If any of the joint found with an unacceptable limit of oxygen content, flow rate and flushing time shall be increased and checking shall be repeated. Minimum next five joints shall be checked for each failure of purging noticed during random inspection in order to monitor the correctness of purging system. In case of high level of oxygen content, the oxygen measurement shall be performed also on the argon contained in the bottle. If the measurement exceeds the maximum permissible oxygen content, the bottle shall be removed and segregated in the stock area separately from the other Argon bottles. A red card indicating, REJECTED shall be attached to the bottle.

8. INSTALLATION - CYLINDER METHOD This method is applicable in particular when soluble paper plugging cannot be adopted (e.g. for absence of line flushing operations). This system allows the weld protection with low gas consumption. The method consist of sealing discs with double packing washer made out of silicon, heat resistant up to 280C / 330C, placed directly next to the welding joint. The minimum distance between the sealing disc and weld joint is 60 mm. Flexible packing washers are adjustable to the corresponding pipe diameter.



T-4.250.901 Rev. A Page 10 of 17

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For complex spool configurations (e.g. elbows) it is recommended to test the cylinder pulling out, before joint clamping or tack welding. The cylinder remains in the pipe until the completion of the welding joint (see figure B). Then the cylinder shall be pulled out, through the next pipe end, using a release cable.

9. PROTECTION OF LARGE DIAMETER WELDS (NPS EQUAL TO OR MORE THAN 14)

In order to reduce the gas consumption, removable foam rubber plugs can be used or internal rings, having an open section suitable to be filled with gas, along the weld root. Minimum distance from plug to weld joint shall be 150 mm. Removal shall be made by means of cable fixed to the plugs.

10. CLOSURE WELDS Closure joints during piping installation, where purging dams cannot be applied, shall be protected by filling the line with backing gas; in order to reduce the gas consumption, advantage from line valves interceptions, when available, can be taken. The minimum time of purging shall be calculated according to (see Figure A).

11. TGX WELDING TGX welding shall be used only with LINDE approval. Separate WPS and PQR shall be done; TGX Wire can be used without purging. TGX can be used where the internal slag can be properly cleaned without affecting FSI.

12. SAFETY REQUIREMENTS Personnel are not permitted to enter confined spaces for the purpose of installation or removal of purge dams without a work permit.

13. WITNESSING AND REPORTING The Welding Supervisors shall maintain a log of all purge dams, recording date of installation and removal using GAM-QCR-QAC-GTL-090.

The LINDE shall witness the removal of all purge dams and initial the purge dam log accordingly. A copy of the purge dam log shall be forwarded to LINDE weekly.



T-4.250.901 Rev. A Page 11 of 17

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14. FIGURES A Purge evacuation of oxidizing atmosphere B Cylinder method


Doc. No. : GAM-MTS-MEC-GTL-006 Rev. D Date: 21.04.2008 QQQ AAA TTT AAA RRR

T-4.250.901 Rev. A Page 12 of 17


Doc. No. : GAM-MTS-MEC-GTL-006 Rev. D Date: 21.04.2008 QQQ AAA TTT AAA RRR

T-4.250.901 Rev. A Page 13 of 17

FIGURE B Cylinder method

Legend:

(1) Protective gas entry with attachment for cable release. (2) protective gas exit (3) heat resistant sealing discs (4) nuts (5) supporting discs (6) porous stainless steel core (7) pipe for porous stainless core (8) Flexible arms. (9) nozzle (10) rigid pipes (11) spring safety hook with release cable (12) Dividing filter. (13) Protective gas pass



T-4.250.901 Rev. A Page 14 of 17

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15. ATTACHMENT

GAM-QCR-QAC-GTL-090 O2 PURGE MONITER IS USING SAME EQUIPMENT SIMILAR (OR)

ACCURACY

C2 ASU PEARL GTL PROJECT

RAS LAFFAN INDUSTRIAL CITY PURGE DAM TRACKING RECORD

ITP NO: REPORT NO:

TEST CODE: DATE:

PURGE DAM INSTALLATION PURGE DAM REMOVAL

ISO NO WELD

NO

GAS FLOW RATE

OXYGENLEVEL

DATE GAMA LINDE DATE GAMA LINDE

NOTES:

GAM-QCR-QAC-GTL-090

ORGANIZATIONS DATE NAME SIGNATURE

GAMA QATAR REP

LINDE REP

QSGTL REP

ARGWELD

WELD PURGE MONITOR MKV

Measures the content of Oxygen in the purge gas to indicatewhen it is safe to carry out a weld

Keeps waiting time to a minimumThe monitor can tell the operator exactly when the Oxygen level is low enough to commence welding. No estimating or guesswork is involved, so no time or gas is wasted waiting for the correct Oxygen level to be reached.

Saves on excessive use of inert gasThe exact Oxygen content is shown on the monitor so no more inert gas than necessary has to be used to ensure that the weld will be free of oxidation.

Prevents weld failuresPremature starts on welds are avoided, high quality welding is ensured. Coked porous and discoloured welds can be prevented.

Highly portableIts small size makes is easy and very convenient to use in all weld purging situations. Battery operation allows it to be carried anywhere.

Titanium / Duplex / Stainless SteelThe MKV monitor can be used to weld Titanium, Duplex and Stainless Steels.

Low costThe monitor is available at a low relative cost and is a perfect accessory for use with any pipe weld purging system or argon welding enclosure.

Continuous monitoring of oxygen levelsA continuous read out of the Oxygen level is given, even when welding is taking place. This can avoid unforeseen purging problems that could cause quality failures after the weld has started.

Calibration and CertificationOur instrument is supplied calibrated and certificates for Industry Standards are included. Re-calibration is available to operators at any time. Continuous calibration on the front of the instrument is provided.

Extra RangeThe MKV monitor indicates Oxygen levels down to 100 parts per million (PPM) 0.01% and measures accurately down to 0.1%.

Huntingdon Fusion Techniques Limited, Stukeley Meadow, Burry Port, Carms SA16 0BU United KingdomTelephone: +44 (0) 1554 836 836 Facsimile: +44 (0) 1554 836 837 Email: [email protected] http://www.huntingdonfusion.com

Copyright 2001-2004 All rights reserved. This publication may not be reproduced by any means without the written permission of Huntingdon Fusion Techniques

Argweld Inflatable Pipe Purging Systems are also available from Huntingdon Fusion Techniques. These are used to dam the volume inside pipework where gas purging is to be carried out.

For pipework where the inflatable systems cannot be removed, we manufacture purge film kits for making water soluble dams.

Argweld Flexible Enclosures have been designed for welding Titanium and other reactive metal components.

These are in wide use for welding of Titanium components for the aerospace, medical and racing car industries and for the welding of stainless steel components to eliminate the expensive cleaning of oxide discoloration.

Special enclosures can be designed and manufactured to suit all applications.

SpecificationsMeasuring Range 0.01% - 20.9 % Oxygen (100 ppm to atmosphere)Accuracy At 20% 0.2% At 2% 0.02%Size in mm 155 x 81 x 38Power Battery type PP3 9vScale LCD (Liquid crystal display)Weight kg 0.210

Shipping Weights and Dimensions

Size in mm 310 x 260 x 80Weight Kg 0.870

With Tungsten inert gas welding, before commencing the weld, it is essential to know that the Oxygen content in the welding volume has been reduced to a satisfactorily low level. The Argweld Weld Purge Monitor is specifically designed to measure Oxygen content down to 0.1% with a high degree of accuracy and to indicate levels down to 0.01% ( 100 ppm).

The Argweld Weld Purge Monitor can be used as a continuous measuring device throughout the weld process or as a sampling instrument for spot checks. Visible demonstrations and routine inspections for quality control are made simple. The monitor can be used with any pipe weld purging system or argon welding enclosure.

Small, portable and very simple to use

The Argweld Weld Purge Monitor is supplied in a robust housing. It comes complete with a stainless steel probe, a 2 metre length of rubber tube, a rubber vacuum bulb and a carrying strap. The instrument can be stored in the plastic foam lined case in which the unit is shipped. Our operating instructions and calibration & test certificates are supplied in the case along with the instrument.

It can be used in a continuous monitoring mode by connecting the rubber tube to the exhaust port on the purging device or enclosure and allowing the exhausted gas to flow free over the sensoraway to the atmosphere.

Alternatively, the monitor can be used in the sampling mode. The stainless steel probe is inserted either through the weld joint gap into the volume being purged or the exhaust port of the purge device. The rubber bulb is then used to draw a sample of the gas across the sensor.

The LCD scale displays the Oxygen level in 13 mm high figures which can easily be read from a distance of several metres.

Once the desired Oxygen level is achieved, welding can begin.

Nothing could be simpler!

We also manufacture a wide range of other products for pipework fabrication and welding. Ask for details about: Trailing shields Weld Backing tape Water Soluble Weld Purge Film Pipe Purging Plugs Titanium Weld Purge Monitor Tungsten Electrode Grinders Multi-Strike Tungsten Electrodes (thoria-free)

(AD05 LT APM MKV GE JUL04)

MS FOR SS .pdf Cylinder method

MS FOR SS PURGING.pdfMS FOR SS PURGING.doc Cylinder method

090-Purge dam tracking record.docISO NOGAS FLOW RATEOXYGEN LEVELPURGE DAM INSTALLATIONDATEGAMALINDEDATEGAMALINDE

MKV O 2 monitor.pdf

006-ms for purging of stainless steel.pdf

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