Ms-mech-10, Ms Fabrication of Piping (1)

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FABRICATION OF PIPING

MS//MECH/10 Revision 01 Page 1 of 13

METHOD STATEMENT FOR FABRICATION OF PIPING

01 Rev. Comments

10, Jan. 2013
Date

M.ADNAN
Prepared by

SAM
Checked by

FI
Checked By PDIL

NAK
Approved by

THIS DOCUMENT IS THE INTELLECTUAL PROPERTY OF DESCON ENGINEERING LIMITED. ANY UNAUTHORIZED USE, INCLUDING THE MODIFICATION AND REPRODUCTION OF THE CONTENT IS STRICTLY PROHIBITED. © COPYRIGHTS ORDINANCE 2002-2008, ALL RIGHTS RESERVED

FABRICATION OF PIPING

MS//MECH/10 Revision 01 Page 2 of 13

INDEX

1. 2. 3. 4. 5. 6. 7. 8. 9.

PURPOSE SCOPE REFERENCES DEFINITIONS RESPONSIBILITIES PROCEDURE TOOLS AND EQUIPMENTS SAFETY INSTRUCTIONS ATTACHMENTS

THIS DOCUMENT IS THE INTELLECTUAL PROPERTY OF DESCON ENGINEERING LIMITED. ANY UNAUTHORIZED USE, INCLUDING THE MODIFICATION AND REPRODUCTION OF THE CONTENT IS STRICTLY PROHIBITED. © COPYRIGHTS ORDINANCE 2002-2008, ALL RIGHTS RESERVED

FABRICATION OF PIPING

MS//MECH/10 Revision 01 Page 3 of 13

1.

PURPOSE
The purpose of this generic method statement is to define the procedure for fabrication of above ground piping under the MAKORI GPF project specification. .

2.

SCOPE
Scope of this method statement covers the following activities.      Material handling Fabrication Welding NDE Inspection

3.

REFERENCES
3.1    3.2    PROJECT DRAWINGS Applicable Project Piping Isometrics . Project Piping Layout drawings. Others. PROJECT SPECIFICATION Piping Specification Approved WPS. Other related Specifications.

3.3  3.4

PROJECT QUALITY PLAN (PQP) Project Quality plan for above ground piping CODES AND STANDARDS ASME B31.3 Pressure Piping ASME B31.1 Power Piping ASME Section V ASME 16.25 Butt Welded Ends ASME 16.5 Pipe Flanges and Flanged Fittings SNT-TC-1A Guidelines of American Society of NDT

THIS DOCUMENT IS THE INTELLECTUAL PROPERTY OF DESCON ENGINEERING LIMITED. ANY UNAUTHORIZED USE, INCLUDING THE MODIFICATION AND REPRODUCTION OF THE CONTENT IS STRICTLY PROHIBITED. © COPYRIGHTS ORDINANCE 2002-2008, ALL RIGHTS RESERVED

FABRICATION OF PIPING

MS//MECH/10 Revision 01 Page 4 of 13

4.

DEFINITIONS
CL PM SM CM DE ITP QC QCI PQP PPE HSE PLAN PM I NCR Client Project Manager Site Manager Construction Manager Discipline Engineer Inspection and Test Plan Quality Control Quality Control Inspector Project Quality Plan Personal Protection Equipment Health Safety & Environment Plan Positive Material Identification. Non Conformance Report.

5.

RESPONSIBILITIES
 It is overall responsibility of PM/SM to organize resources to perform construction activities as per project specification, in compliance with quality, schedule & safety requirements. It is the responsibility of CM that construction activities are executed according to the relevant project specifications, in compliance with quality, schedule & safety requirements. DE will ensure that all the works are performed safely as per latest Approved For Construction (IFC) drawings & specifications. The relevant DE and Supervisor will ensure that all the piping work is conducted in accordance with this method statement and project specifications The QCI will ensure that all work is executed according to PQP and that requirements of quality dossier are full filled. Safety and construction supervision will be carried out under responsibility of Client wherever required.



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6.
6.1

PROCEDURES – METHOD OF WORKS – INSTRUCTIONS
RECEIPT & STORAGE OF PIPE RAW MATERIALS  The piping raw material received from client shall be offloaded in designated lay down yard.
3

THIS DOCUMENT IS THE INTELLECTUAL PROPERTY OF DESCON ENGINEERING LIMITED. ANY UNAUTHORIZED USE, INCLUDING THE MODIFICATION AND REPRODUCTION OF THE CONTENT IS STRICTLY PROHIBITED. © COPYRIGHTS ORDINANCE 2002-2008, ALL RIGHTS RESERVED

FABRICATION OF PIPING

MS//MECH/10 Revision 01 Page 5 of 13



During offloading, pipes shall not be dropped off the transport. A crane and suitable certified slings shall be used. Nylon slings will be used to handle SS and coated piping & fittings. The pipes shall be placed on concrete blocks with wooden packing in between. They shall be adequately supported to minimize sagging. The piping end covers shall be kept in place to prevent foreign particle entry into the pipes. All material shall come with color-coding as per size, material & schedule. The piping material shall be segregated accordingly to facilitate location of the items. Alloy. SS, NACE, Low Temperature CS, CS and Galvanized pipe & fittings to be stored separately.

3

   

6.2 PAINTING



Painting shall be done according to project specifications spec No. PC12002-39505-SP-003

6.3 SPOOL BREAKDOWN    The piping isometrics shall be marked into number of spools to facilitate the fabrication & erection work. Each spool shall be marked with a unique number. Each joint on the isometric will be given a unique number preparing a welding map for traceability. Separate numbering system will be followed for butt welds, fillet welds, threaded joints etc. The details of piping isometric breakdown into spools and joints will be recorded for reference.



6.4 PIPING FABRICATION   Material will be shifted from lay down area to work shop as per relevant piping isometric drawings Carbon steel, low temperature carbon steel, NACE and stainless steel pipe fabrication work will be done in separate areas. Tools & equipment compatible with the material in fabrication shall be used. The piping material is to be used in appropriate and economical way. All cuttings should be collected separately as per material code and place in order to make best use of these. Cuttings of other then alloyed material may be considered as waste up to maximum 1000mm, and should be stored separately.





THIS DOCUMENT IS THE INTELLECTUAL PROPERTY OF DESCON ENGINEERING LIMITED. ANY UNAUTHORIZED USE, INCLUDING THE MODIFICATION AND REPRODUCTION OF THE CONTENT IS STRICTLY PROHIBITED. © COPYRIGHTS ORDINANCE 2002-2008, ALL RIGHTS RESERVED

FABRICATION OF PIPING

MS//MECH/10 Revision 01 Page 6 of 13



Pipes for socket weld joints shall be cut square

6.4.1

CUTTING AND BEVELING

6.4.1.1 BUTT JOINT  The pipes shall be cut as per dimensions mentioned in the isometric and all pipe length shall be marked with the relevant spool No, as given in the isometric. Material traceability shall be maintained as per relevant agreed QIP. Based on spool break down of piping isometrics, pipe lengths shall be cut 150mm extra length for pipe will be provided in spools for field adjustment. The pipe ends for 2 inch & above shall be beveled as per approved WPS for the piping class. The cutting and beveling of pipes shall be done by mechanical means cold cutting beveling machine/ lathe machine, flame cutting or plasma/ arc cutting, cutting shall be acceptable provided that the edges are smooth. When torch cutting or arc cutting are used for alloy steel or stainless steel, after grinding to sound metal a dye penetrate examination shall be performed to eliminate the possibility of surface cracks. The fit up of pipe ends, fittings & weld neck flanges shall be done to obtain uniform root opening. The criterion given in related WPS shall be followed. The joint should be free of grease, oil, scales, rust or other foreign material. The primer paint coat on pipe & fitting ends shall be removed prior to bevel end preparation. The pipes shall be tack welded by a qualified welder. If the pipes are of different thickness, the larger thickness will be tapered in compliance with standard to match the smaller thickness. The adjacent section of longitudinally welded pipes that are to be joined by buttwelds shall have longitudinal weld seams positioned such that they are at least 30 apart from horizontal center line. The fabricator will also not locate longitudinal weld seams on top or bottom of the pipe so that branch connections are not located on the seam. Reinforcement pads shall be fabricated only if required in the isometric. The material for reinforcement pad shall be same as that for the pipe unless otherwise authorized by Client. The size & thickness of pad will be as specified in the







   





THIS DOCUMENT IS THE INTELLECTUAL PROPERTY OF DESCON ENGINEERING LIMITED. ANY UNAUTHORIZED USE, INCLUDING THE MODIFICATION AND REPRODUCTION OF THE CONTENT IS STRICTLY PROHIBITED. © COPYRIGHTS ORDINANCE 2002-2008, ALL RIGHTS RESERVED

FABRICATION OF PIPING

MS//MECH/10 Revision 01 Page 7 of 13

isometric. It is preferable that the pad shape is circular, however, the pad size may be altered provided equivalent cross sectioned area is maintained as per ASME requirement. The pad shall have a 1/8” NPT vent hole, drilled & tapped to NPT prior to installation of reinforcement pad. 

The Flanges indicated on isometric to be supplied loose shall be tack welded with the pipe. Full welding shall be made after site checking.

6.4.1.2 SOCKET JOINT  The pipe for welded sockets joint shall be ground to remove burrs due to cutting. A gap between end of pipe & bottom of socket will be maintained as per Project Specifications.

6.4.1.3 THREADED JOINT  In case of threaded pipes (for utilities piping only) screw threads shall be concentric with axis of pipes with no burrs or stripping. The threading dies shall be sharp & properly designated for the piping material.

6.4.1.4 GALVANIZED PIPES  The pipe work 3 inch & larger shall be fabricated in flanged spools as per design. The size of spools shall conform to dimensions of hot dip galvanizing bath. The same shall be galvanized from both inside and outside. The threaded joints of galvanized pipes shall not be seal welded. Tape/ sealant will be used as per project specification.



6.4.2

MATERIAL TRACEABILITY  Material traceability No.MS/MECH/02. shall be accordance to the Method Statement

6.5 WELDING.    All welding work will be according to approved WPS and B31.3 and only qualified welders shall be employed. Heat treatment will be indicated on WPS, where required. The welding work piece will be shielded against high winds and rain. The wind speed exceeding 10 m/sec and 3 m/sec for SMAW & GTAW respectively.

THIS DOCUMENT IS THE INTELLECTUAL PROPERTY OF DESCON ENGINEERING LIMITED. ANY UNAUTHORIZED USE, INCLUDING THE MODIFICATION AND REPRODUCTION OF THE CONTENT IS STRICTLY PROHIBITED. © COPYRIGHTS ORDINANCE 2002-2008, ALL RIGHTS RESERVED

FABRICATION OF PIPING

MS//MECH/10 Revision 01 Page 8 of 13

    

The weld surface shall be cleaned with wire brush or grinding prior to welding operations to give a surface free from rust, scale or mill coating. Between each layer of welding any cracks, pores or welding spatters shall be removed by grinding the surface before application of next layer. The appearance of finished welds shall conform to ASME B31.3 code & WPS and shall exclude any under cuts, spatters, and cracks. All branch connections shall be joined to headers with full penetration welding. The bore side shall be ground smooth, free from cracks. For flange to pipe connections if welding shrinkages can lead to misalignment, two similar flanges shall be joined by inserting a temporary gasket and then welded. The distance between centrelines of adjacent grith butt welds and staggering of longitudinally welded pipe for making butt weld shall be according to project specification. Preheating shall be done in accordance with the welding requirement related to each class of piping base metal material. Welding shall be performed to ensure complete fusion of the weld deposit and the base metal in order to obtain homogeneous bound over the entire cross section area of the weld. Welding current and polarities shall comply with the approved WPS. And or instruction given by the manufactures of the filler metal. Number of layers shall never be less then two.



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 

6.6 POST WELD HEAT TREATMENT (PWHT) 6.6.1   GENERAL Before starting any heat treatment process, it will be checked that welding has been completed. The temperature can be checked with the aid of thermochrome crayons or thermocouples.  The preheating temperature shall be maintained throughout the welding cycle and it should be done over sufficient width on either side of welds.  If ambient temperature of 00C or below preheating is mandatory even if not specified. No heat treatment is required for austentic stainless steel.

THIS DOCUMENT IS THE INTELLECTUAL PROPERTY OF DESCON ENGINEERING LIMITED. ANY UNAUTHORIZED USE, INCLUDING THE MODIFICATION AND REPRODUCTION OF THE CONTENT IS STRICTLY PROHIBITED. © COPYRIGHTS ORDINANCE 2002-2008, ALL RIGHTS RESERVED

FABRICATION OF PIPING

MS//MECH/10 Revision 01 Page 9 of 13

  6.6.2  

Thermocouples and their location on the job to be heat reated shall be checked. Calibration certificates of the heat treating equipment shall be checked. POSTWELD HEAT TREATMENT PROCEDURE Stress relieving shall be performed as per project specification when specified for relieving residual stresses caused by welding, cold working etc. Stress relieving shall be performed when specified to obtain softer, more ductile material than is obtained by stress relieving. Normalising is the usual commercial annealing operation for low carbon steels. It shall be formed as follows: A Heat material up to 16500F B Hold at temperature one hour per inch of thickness (but not less than 1/2 hour). C Air cool at room temperature.

 

Normally austentic stainless steel is not stress relieved, If relief of stress is mentioned in the project specification, then a full anneal shall be specified. Full annealing of austentic stainless steel shall be performed when specified to obtain solution of carbides and maximum softness and ductility with adequate corrosion resistance. It shall be performed as follows: A Heat material to 20000F). B Hold at temperature one hour per inch. of thickness (but not less than 1/2 hour). C Water steam or air blast quenched to room temperature. (If distortion is excessive rapid air cool may be used, although this will result in decreased corrosion resistance).



Annealing shall be performed when specified to obtain maximum softness and ductility. Full annealing is used on low carbon steels only where maximum formability is needed but is used on medium carbon and low alloy steels where normalising may not produce the desired properties. It shall be performed as follows: A Heat material to 17500F B Hold at temperature for one hour Slow furnace cool to 10000 F. C Air cools from 10000 F to room temperature.

  

When local annealing is applied the zone to be heated to annealing temperature shall be at least four times as wide as the weld. No further heating or welding shall be done after annealing. For welding sensitive materials a hardness test shall be performed to evidence that annealing was carried out perfectly.

THIS DOCUMENT IS THE INTELLECTUAL PROPERTY OF DESCON ENGINEERING LIMITED. ANY UNAUTHORIZED USE, INCLUDING THE MODIFICATION AND REPRODUCTION OF THE CONTENT IS STRICTLY PROHIBITED. © COPYRIGHTS ORDINANCE 2002-2008, ALL RIGHTS RESERVED

FABRICATION OF PIPING

MS//MECH/10 Revision 01 Page 10 of 13

   6.6.3 

After heat treatment hardness of weld will be checked as per specification (if required) and hardness test report shall be prepared. A record of temperature levels and period of treatment should be maintained for reference. After completion of process resultant graph of time and temperature will be verified and heat treatment sheet shall be prepared. PRECAUTIONS Heat treatment operations involve electrical heating up to 2000°F bringing hazards of burning & electrocution due to a lot of cables & other electric equipment. Following precautions shall be taken. A Appropriate visual & physical barrication of area to avoid unauthorized personnel's entry B To avoid physical hindrance due to other nearby activities. C Warning signs / boards shall be installed on barrications,

D Proper dressing up of cables through appropriate routes to avoid entangling with other activities. E ELCB’s shall be installed on power supplies. 6.7 INSPECTION   The fabricated pipe spool shall be checked against project drawings to verify its compliance. The dimensions, angle and direction of spool and allowances for field welding shall be according to the IFC isometrics & project specification. (ASME B.31.3 (chapter “V”) NDE shall be performed as per ASME section “V” after PWHT if specified on isometric drawings or project specifications. The acceptance criteria for visual inspection shall be done according to the ASME B.31.3. (Chapter VI). Visible small transverse cracks & star cracks of limited thickness shall be removed by grinding & repaired by welding. However circumferential cracks shall result in weld rejection. The defective material will be cut out & rewelding preformed. NDE tests shall be performed & recorded as per Piping Class, relevant Code and Project (Welding) Specifications. The NDE result shall be interpreted by qualified inspectors (level II)

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THIS DOCUMENT IS THE INTELLECTUAL PROPERTY OF DESCON ENGINEERING LIMITED. ANY UNAUTHORIZED USE, INCLUDING THE MODIFICATION AND REPRODUCTION OF THE CONTENT IS STRICTLY PROHIBITED. © COPYRIGHTS ORDINANCE 2002-2008, ALL RIGHTS RESERVED

FABRICATION OF PIPING

MS//MECH/10 Revision 01 Page 11 of 13

  

Branch connections shall be examined by dye penetration or magnetic particle or ultrasonic methods or as per Project Specification & relevant Code. All welding records for each joint shall be maintained throughout the fabrication work. CS, SS and Low temperature carbon steel material tracibility shall be maintained through out the fabrication work such that location & heat numbers of all welded pressure retaining pipe component is maintained. The heat number will be transferred by permanent marker to all pieces cut from main pipe.

6.8 IDENTIFICATION 

Each fabricated spool shall be clearly marked with a number. This number shall include line number & spool number as shown on the piping isometric. (For piping up to diameter 6 inch) it will be hard marked on to a steel plate 2x 3x 1/16 inch which shall be securely wired to the pipe. (However for piping greater than 6 inch diameter the number will mark on inside of the pipe using a permanent marker.)

6.9 STORAGE     

The pipe spool complete in all respect shall be stored separately. All spools shall have their identification/piece number clearly designated on each spool. The spool will be cleaned in an inclined position by tapping so that all foreign materials are removed. The spool shall be placed on wooden baton to avoid direct contact with soil. The open ends shall be covered by polyethene sheets or end caps. In case of flanged spools the same shall be covered by securely tied wooden blanks to avoid foreign material entering the pipes. The spool shall be handled using nylon lifting slings. Alloy / SS to be stored separate form CS.

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6.10 PIPE SUPPORTS, FABRICATION.  Pipe support as specified on isometrics & general arrangement drawings shall be fabricated according to pipe support detail drawings.

THIS DOCUMENT IS THE INTELLECTUAL PROPERTY OF DESCON ENGINEERING LIMITED. ANY UNAUTHORIZED USE, INCLUDING THE MODIFICATION AND REPRODUCTION OF THE CONTENT IS STRICTLY PROHIBITED. © COPYRIGHTS ORDINANCE 2002-2008, ALL RIGHTS RESERVED

FABRICATION OF PIPING

MS//MECH/10 Revision 01 Page 12 of 13

  

The fabricated support shall be painted after surface preparation as per project specifications. The procedure of welding pipe support attachments to pipe work shall be generally similar as that for pipe work and qualified welders shall be employed. Pipe support welding on piping requiring PWHT shall be done prior to the heat treatment.

7.

TOOLS & EQUIPMENTS

7.1         

EXECUTION

Hand Tools Cutting, Beveling & Grinding Machines Cranes (Mobile) Cranes (Tower) if required Lathe Machine Hack Saw Trailer Stress Relieving Equipment Welding Machine

7.2       

SAFETY Safety helmet Safety Goggles Gloves Safety Shoes Welders Helmet Ear Plugs/Muffs (if required) Dust mask (If required)

7.3    

TESTING Radiography Ultrasonic Testing Mage Particle Testing Dye Penatrant

THIS DOCUMENT IS THE INTELLECTUAL PROPERTY OF DESCON ENGINEERING LIMITED. ANY UNAUTHORIZED USE, INCLUDING THE MODIFICATION AND REPRODUCTION OF THE CONTENT IS STRICTLY PROHIBITED. © COPYRIGHTS ORDINANCE 2002-2008, ALL RIGHTS RESERVED

FABRICATION OF PIPING

MS//MECH/10 Revision 01 Page 13 of 13

8.

SAFETY INSTRUCTIONS
During execution of the job all measure shall be adopted to ensure safe working. DE will ensure that, PTW system shall be implemented as per client requirements in CPF and GPF areas.              DESCON site management system (latest revision) will be implemented. All personnel involved will use necessary PPE as required. The workers will be made aware of safety requirements related to this activity through daily, weekly and monthly toolbox and safety talks. Safety notice board will be installed. All equipment will be inspected by E&P (DESCON) as per routine while execution supervisor should inspect it prior to use. During transportation of pipes and other fittings, the material shall be properly supported and tied on the Trailer. Ensure that pipes are properly wedged or blocked to avoid rolling. Correct rigging procedure should be observed. Access and good housekeeping should be maintained in all fabrication areas. Fire extinguisher should be available in all working areas. Proper storage, handling and use of gas cylinders will be observed. All cylinders shall be kept in trolleys and in an upright position. Welding sets should be checked and maintained regularly for wear and tear. Waste Management should be strictly followed to keep the job site neat and clean. HSE shall provide due support to the execution team in the fulfillment of HSE requirements.





9.

ATTACHMENTS.
 Nil.

THIS DOCUMENT IS THE INTELLECTUAL PROPERTY OF DESCON ENGINEERING LIMITED. ANY UNAUTHORIZED USE, INCLUDING THE MODIFICATION AND REPRODUCTION OF THE CONTENT IS STRICTLY PROHIBITED. © COPYRIGHTS ORDINANCE 2002-2008, ALL RIGHTS RESERVED

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