Piping Fabrication Procedure.pdf

Doc Ref : QCP-03

PIPING FABRICATION PROCEDURE

Date : 1st Janu ary 2009 Revisio n No : 0 Page 1 of 10

TABLE OF CONTENTS

SECTION

DESCRIPTION

1.0

PURPOSE

2

2.0

SCOPE

2

3.0

REFERENCE

2

4.0

DIFINITION

2

5.0

PROCEDURE 5.1 5.2 5.3 5.4 5.5 5.6 5.7

GENERAL FIT-UP PREHEATING REQUIREMENTS N.D.T POST WEALD HEAT TREATMENT (PWHT) PAINTING OF PIPE SPOOLS THREADED PIPE, FITTING AND SOCKET WELDS 5.8 PIPE SUPPORTS 5.9 FLANGE ALIGNMENT CHECKS 5.10 FLANGE ALIGNMENT TOLERANCES 5.11 SHAFT ALIGNMENT DISPLACEMENT LIMITS 5.12 HYDROSTATIC TEST 5.13 REINSTATEMENT 5.14 PIPING MAKE-UP CONDITION

PAGE

2-3 3-4 4 4 5 5 5 6 6-8 8-9 9 9 10 10

6.0

SPECIAL REQUIREMENT

10

7.0

RECORDS

10

Doc Ref : QCP-03



1.0

PURPOSE This procedure serves as a guideline in carrying-out Piping Fabrication to ensure systematic approach of work and the requirements are followed.

2.0

SCOPE This procedure covers the processes associated for the Piping Fabrication, such as mark , cutting, Fit-up, Weld-up, Testing, Painting etc.

3.0

4.0

REFERENCE ASME B31.3

Chemical Plant and Petroleum Refinery Piping

ASME 1X

Boiler & Pressure Vessel Code (Welding and Brazing Qualification)

DEFINITION WPS SMAW NDT DPI MPI RT UT PWHT NPS API TFE

5.0

-

Welding Procedure Specification Shielded Metal Arc Welding. Non-Destructive Testing Dye-Penetrant Inspection Magnetic Particle Inspection Radiographic Test. Ultrasonic Test. Post Weld Heat Treatment Nominal Pipe Size American Petroleum Institute, Poly-tetra-fluoroethylene

PROCEDURE 5.1

General 5.1.1

It is the responsibility of the Production Superintendent to ensure that key personnel involved in piping Fabrication understand fully the requirement mentioned in this procedure.

5.1.2

All storage, traceability, identification, tolerances, welding, Inspection and testing shall be carried out as stipulated within the specifications, procedures and codes.

Doc Ref : QCP-03



5.2

5.1.3

All materials shall have end caps inserts or plug fitted on pipes, valves, fitting etc. during or after blasting and painting activities.

5.1.4

Only qualified welders that have been approved by Client shall be used for any piping welding.

5.1.5

The electrodes or wire to be utilized for piping welding will be as stipulated in each W.P.S as approved by Client

5.1.6

All welding information for each specific operation shall be displayed at the working area. Welding consumable control, shall be as stipulated in QCP-06

5.1.7

The Quality Control Section shall develop and maintain a record of each welder’s performance. This record shall show the defect rate of each welder, based on linear weld length.

5.1.8

Prior to any fit-up or welding, all material i.e. pipe, fitting, valve etc. shall be recorded and documented as stipulated in Material Control Procedure

FIT-UP Pipe spool fit-up shall be carried out in a professional manner adhering to isometric drawings and tolerances. 5.2.1

Small bore pipe can be fit-up with the use of angle bar. Large bore pipe shall be fit-up with the use interior or exterior line up clamps HI-LO shall be kept within tolerances as stipulated in ASME B31.3i.e.,± 1.6 mm.

5.2.2

Snaking and distortion in pipe spools shall be limits 1.5 mm per meter length.

5.2.3

After marking the pipes as per the isometric drawing. The pipe shall be checked by QC Inspector. After mark-up has been checked by the piping Supervisor and the pipe should be cut as per mark-up.

5.2.4

5.2.5

Fit-up tack welds are allowable and if in the root shall be as per WPS electrode requirement and bridge tacks are also allowable using SMAW. All tack’s using SMAW electrodes shall be removed during the welding of the joint.

Doc Ref : QCP-03



5.3

5.2.6

The fit-up spool at this stage shall be submitted to QC Inspector for their approval and fit-up to be signed prior to any welding on the spool.

5.2.7

All pipe prior to fit-up, shall be internally and externally cleaned to a minimum of 5mm from the edge preparation and shall be free of rust and surface contamination.

5.2.8

The spool fit-up can now be welded as per the relevant WPS and preheating requirements as specified in the WPS and section 5.3 of this procedure.

5.2.9

The completely welded pipe spool shall be visual and the dimension inspected by the QC Inspector prior to NDT.

5.2.10

Welding Supervisor shall ensure that there is adequate ventilation at the work place prior to any purging of pipe works.

PRE-HEATING REQUIREMENTS 5.3.1 Pre- heating shall be accordance with Client specification, applicable codes, standards and administered in accordance with combined thickness and WPS pre-heating requirements. Pre-heating shall be carried out by electrical resistance or induction equipment or with gas acetylene /propane/butane burners and monitored by the used of tempilsticks. The preheating temperature shall be established over an area 75mm on each side of the joint configuration. Each welder shall be provided with a set of tempilstick to monitor the preheating requirement for the joint to be welded.

5.4

NDT 5.4.1 All non-destructive Testing (RT, MPI, DPI, and UT) shall be carried out after the spool has been visually accepted by the QC Inspector and documented. NDT requirement will be performed as per isometric drawing and NDT Procedure. All NDT results shall be documented. 5.4.2 Weld repairs shall be carried out as per the relevant WPS and in accordance to Client specification and welding repairs procedure.

Doc Ref : QCP-03



5.5

POST WELD HEAT TREATMENT (PWHT) Post Weld Heat Treatment (PWHT) shall be carried out as per QCP-7.

5.6

PAINTING OF PIPE SPOOL 5.6.1 Following satisfactory NDT and PWHT results, pipe spools can be released for painting. 5.6.2 Pipe spools shall be blasted to SA 2.5 or Clients requirement and primed as per the requirements of the painting procedure. All pipe spools intended for insulation and heat tracing shall be blasted and primed only. 5.6.3 Where possible all pipe spools will have it’s final coat completed prior to erection fit-up. Pipe spools with field welds will be spot blasted and primed and final coated in-situ.

5.7

THREADED PIPE, FITTINGS AND SOCKET WELDS 5.7.1 All treaded pipe and pipe fitting, shall be installed with the use an anaerobic pipe thread sealant with T.F.E. on the following which do not required seal welding. a) Plugs and cap for drain and vent valves. b) Thermowell c) Union ring threads and union bonnets of valves. d) Instrument tubing fittings. e) Union nut rings. 5.7.2 For service employing hydrocarbon, acid and toxic materials, threaded connection shall be seal welded. The threads are to be made up using no sealant and two threads maximum exposed followed by back welding. 5.7.3 Seal welding shall be done with electrode not to exceed 3.2mm in diameter using amperage in low range. 5.7.4 Prior to assembly, all cutting oil shall be removed. 5.7.5 All small bore fitting shall be arranged and storage at the rack between type threaded and non-threaded.

Doc Ref : QCP-03

PIPING FABRICATION

Date : 1st Janu ary 2009 Revisio n No : 0

PROCEDURE

Page 6 of 10

5.8

PIPE SUPPORTS 5.8.1 Ensure that pipe guide, anchor, sliding shoes, stoppers are Installed correctly where specified according to the IFC drawings 5.8.2 Field Engineer Inspect the spring hanger/ supports to ensure that the type (suspension, compression variable load of fixed load types) and capacity are correct and that the actual loading is within designed capacity. 5.8.3 For insulated piping, ensure that the load is transmitted directly from the piping to the supporting structure through the pipe support, and not through the insulation. 5.8.4 Ensure that correct type of flexible connections is installed where specified in the IFC drawing or by the machinery vendor. 5.8.5 Ensure the reinforced.

5.9

pipe

support’s

foundations

are

adequately

FLANGE ALIGNMENT CHECKS 5.9.1 The out-of parallel alignment check and out-of axial alignment check shall be performed to all flange connections between the piping and the machinery.

(A) Out- of Parallel Ali gnment Check

P2

P1

FIGURE 1

Doc Ref : QCP-03



5.9.2. The out-of parallel alignment shall be performed using a vernier caliper. The measurement shall be taken using the outer periphery of the inner flange face as the datum. Out-of parallel alignment will be the results of P1 minus P2 as shown in Figure 1. 4 set of measurements. Each 90° apart shall be taken. The points selected to measure shall be the point with maximum misalignment.

(B) Out-of Axial Alignment

FIGURE 2 The measurement shall be taken at the intersecting point of the flange radii and the bolt hole periphery nearest to the flange centre. (Refer figure 2 for typical point) In order to eliminate the manufacturing tolerances in the flange outside diameter, the average of the measurement at two points directly opposite each other will be considered the actual out-of axial alignment

Doc Ref : QCP-03

PIPING FABRICATION

Date : 1st Janu ary 2009 Revisio n No : 0

PROCEDURE

Page 8 of 10

(c) Out-of Radial Alignment (Bolt Hole Alig nment)

-Should not exceed 2mm

FIGURE 3 At least two sets of measurement, each 90° apart shall to be taken. The point selected to measure shall be the point with the maximum misalignment. Neither of the readings shall exceed the limits specified in Para 5.10

5.10

FLANGE ALIGNMENT TOLERANCES All flanges connection between the piping and rotating equipment shall be aligned to within the following tolerances. NORMAL SERVICE

SPECIAL SERVICE Design Temp. 454°C or Flange, Rating ANSI CL900

Out-of Parallel Alignment

3/32 in. per ft. (1:125) of nominal pipe diameter max. out of parallel alignment of flanges measured at any point on the flange circumference

1mm maximum, measured across any diameter

Out-of Axial Alignment Flange Face Separation

3mm maximum Space required for gasket ±1.5mm

3mm maximum Space required for gasket ±1.5mm

Ad di ti on al Requir ement fo r Pip in g Ov er 80mm NPS

Doc Ref : QCP-03



Equipment having pipes over 80mm NPS shall be checked for displacement of the drive shaft alignment due to the forces imposed from the pipes to the equipment. The shaft alignment displacement check shall be performed in the following sequence: i)

Align the driver and driven equipment drive shafts to vendor specified tolerances with piping disconnected.

ii) Install and tighten all hold-down/ anchor bolts and/ or dowel. iii) Recheck drive shafts alignment with the pipes connected and tightened, to determine the drive shaft displacement due to forces imposed by the pipes. All the drive shaft alignment data shall be recorded.

5.11

SHAFT AL IGNMENT DISPLACEMENT LIMITS a) Alignment for pipes over 80mm NPS connected to rotating equipments shall be acceptable if the resultant drive shaft displacement due to the forces imposed by the pipes are within the vendor specified allowable displacement. b) In case which vendor specified tolerances are not available, the following API standard shall be followed: API STD 610 For centrifugal pump, the maximum drive shaft displacement measured at the coupling on the installed pump is 127 micrometer (0.005 inch)in any direction. API STD 617 For centrifugal compressors, the maximum shaft displacement measured at the coupling on the installed compressor is 50 micrometers (0.002 inch) in any direction.

5.12

HYDROSTATIC TEST Hydrostatic Test shall be carried out as per QCP-10

Doc Ref : QCP-03



5.13

REINSTATEMENT Pipe spool and valves that has been removed for hydrotesting shall be reinstated. Reinstatement check of flange connection shall be as per para 5.9 and tolerances as per para 5.10

5.14

PIPING MAKE-UP CONDITION Prior to make-up of flange, flange faces shall be check for damages Flange faces shall be aligned to the design plane to within 1mm measured across any diameter. Flange bolt holes shall be aligned to within 2mm offset.

6.0

SPECIAL REQUIREMENT. NIL

7.0

RECORDS NIL

Piping Fabrication Procedure.pdf

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