6-44-0503-Rev0

STANDARD SPECIFICATION FOR PIPING FABRICATION AND

INSTALLATION FOR OFFSHORE APPLICATION

STANDARD SPECIFICATION No.

6-44-0503 Rev. 0 Page 2 of 13

Format No. 8-00-0001-F1 Rev. 0 Copyright EIL – All rights reserved

Abbreviations: GAD : General Arrangement Drawing NB : Nominal Bore P & ID : Piping & Instrumentation Diagram ASME : American society of Mechanical Engineers ASTM : American society for Testing and Materials NACE : National Association of Corrosion Engineers WPS : Welding Procedure Specification PQR : Procedure Quality Record Piping Standards Committee Convenor : Mr S Chanda Members : Mr V K Bhatli Mr AT Dharmik Mr P K Bali Mr R Nanda Mr L B Ajwani Mr D Khare(HMTD) Mr PP Lahiri/S Ghosal(SMMS) Mr GK Iyer(const.) Mr R K Bhandari(Proj.)




6-44-0503 Rev. 0 Page 3 of 13


CONTENTS

1.0 SCOPE………………………………………………………………..........4

2.0 CODES AND STANDARDS……………………..……………………….4

3.0 FABRICATION………………………………………………..…………..4 4.0 WELDING……………………………………………………….……..….5

5.0 EXAMINATION, INSPECTION AND TESTING……………………….6

6.0 INSTALLATION………………………………………………………….9

7.0 REQUIREMENT OF BOLT TENSIONING

AND BOLT TORQUING………………………………………………..10

8.0 PROTECTIVE COATING……………………………………………….11

9.0 INSULATION……………………………………………………………11

10.0 SHIPPING AND HANDLING…………………………………………..11

11.0 FIG-1 DIMENSIONAL TOLERANCES………………………………..13




6-44-0503 Rev. 0 Page 4 of 13


1.0 SCOPE

This specification covers the requirements governing the fabrication, installation, inspection & testing of piping assemblies in shop or field. This specification is to be used with the individual specification and/or drawings, if furnished. In case of conflict, the individual specification and /or drawings shall govern.

2.0 CODES AND STANDARDS

All piping shall be designed, fabricated and installed as per codes & standards as mentioned in Piping Design Criteria except as modified by this specification.

3.0 FABRICATION

3.1 Carbon steel pipes shall be cut by mechanical or thermal cutting depending upon

thickness and size however thermal cutting shall not be employed for galvanized and stainless steel materials.

3.2 Bevel end preparation shall be done by bevel cutting machines and suitably grinded. 3.3 For pipes up to 2 Inch NB, the internal burrs shall be removed by suitable grinding. 3.4 Dimensional tolerances: In addition to the tolerances contained within specified

codes and standards, dimensional tolerances for finished fabricated piping shall conform to those shown in Figure-1 attached herewith.

3.5 Care shall be taken during cutting & welding such that the final dimensions of

spools are within the applicable tolerances. 3.6 Minimum spacing of circumferential welds between centerlines shall not be less

than four times the pipe wall thickness or 100 mm, whichever is greater. 3.7 Threaded, Socket Weld & Brazed Piping

3.7.1 Threads shall be clean cut with no burrs or stripping and shall be according to ASME B1.20.1, tapered. Dies shall be new, sharp and properly designed for the piping material. Ends shall be reamed to remove burrs.

3.7.2 Immediately before erecting the piping all threads of pipe and fittings shall

be thoroughly cleaned of cuttings, dirt, oil or other foreign matter. The male threads shall be coated with thread sealant and the piping made up sufficiently for the threads to seize. Sealant shall be Teflon tape.

3.7.3 Threaded connections shall be gauge checked or chased after welding or heat

treatment.

3.7.4 When socket weld/brazed fittings or valves are used, pipe shall be spaced approximately 1/16-inch to avoid “bottoming” which could result in excessive weld stresses.

3.7.5 The inside of the brazed fitting and outside of the tube shall be cleaned with sand paper. Flux paste to be evenly applied to the joint.

3.7.6 Brazing temperature shall be achieved as quickly as possible using a suitably sized torch.




6-44-0503 Rev. 0 Page 5 of 13


3.7.7 Seal welding of threaded connections when specified shall include the first

block valve, cover all threads and be done with electrodes not to exceed 1/8 inch in diameter. The joint shall be cleaned of all cutting oil & other foreign material and made up of dry to full thread engagement. Thermo wells shall not be seal welded.

3.8 Branch connections

3.8.1 All branch connections shall be joined to the header with full penetration

welds.

3.8.2 Reinforcing pads shall be added only after external and internal visual inspection of the attachment. Reinforcing pads shall be provided with ¼” tapped weep hole. Weep holes shall be plugged after completion of welding.

3.9 Exposed machined and threaded surfaces shall be protected from oxidation during

heat treatment. 3.10 Flange bolt holes shall straddle the established horizontal and vertical centerlines of

the pipe except where connection to equipment dictates otherwise. 3.11 Cleaning of the piping after fabrication and heat treatment shall be performed

externally and internally to remove all loose scale, weld spatter, sand and other foreign materials.

3.12 All piping supports shall be fabricated and installed as per approved

drawings/standards.

4.0 WELDING 4.1 Welders and welding procedure shall be qualified per ASME B 31.3, latest

edition.

4.2 For 90-10 Cu-Ni piping, welders and welding procedures shall be qualified as per ASME Code Section IX.

4.3 Welding shall be performed as per approved WPS and PQR.

4.4 No chill rings or backup rings are to be used.

4.5 The joints to be field welded shall be beveled as per ASME B 16.25

4.6 The deposited filler metal shall match the chemistry and minimum physical properties when similar metals are welded.

4.7 Stress relieving shall be as per ASME B 31.3.

4.8 Welding of low sulphur NACE carbon steel and duplex stainless steel shall be as per 6-79-0012 and 6-79-0016 as applicable.




6-44-0503 Rev. 0 Page 6 of 13


5.0 EXAMINATION, INSPECTION & TESTING

5.1 Random radiography shall be performed on one weld in each 10 welds for each

welder on the following: a) Water (in case of Carbon steel) b) Air c) Chemicals d) Diesel e) Closed drain f) Relief g) Hydraulic oil h) Oily water i) Slops

5.2 25% Radiography shall be performed on the following: a) Glycol & Therminol b) Vent gas c) Lube oil & seal oil

5.3 100% Radiography shall be performed on size 2” and above and 25% on sizes below 2” for the following: a) Crude oil b) Jet fuel c) Fuel gas / Instrument gas d) Process gas e) Production flow lines (Well fluid) f) Injection water g) Hydrocarbons (process) h) HP & LP flare lines

5.4 For fillet welds and brazed joints where carrying out radiography is not possible, magnetic particle or dye penetrant test shall be carried out. The extent of inspection shall remain same as for radiography.

5.5 All the lines, which are stress relieved or have design pressure more than 50 kg/cm2 shall be fully radio graphed (100%) even if not required as per clause 5.1 to 5.3.

5.6 Radiographic procedure shall be as per ASME B 31.3.

5.7 Acceptance criteria based on visual, radiography and other types of examination shall be as per ASME B 31.3 with the following modifications. 5.7.1 The internal weld protrusion on ‘pigged lines’ shall not exceed 1.6 mm

(1/16 inch). 5.7.2 Orifice flange butt welds shall be internally ground smooth and flush. 5.7.3 For 90-10 Cu-Ni piping, radiographic examination of welds shall be as

per ASME Section VIII, UW 51.

5.8 Hydrostatic testing is not required for shop-fabricated piping where the pipe is to be field-tested. Hydrostatic testing is required on skid-mounted




6-44-0503 Rev. 0 Page 7 of 13


assemblies. Pressure test shall be performed as per ASME B 31.3 and the appropriate specification class chart.

5.9 All instruments shall be excluded during hydro test.

5.10 All piping shall be flushed prior to hydro testing.

5.11 Those field weld joints, which cannot be leak tested due to unavoidable reasons, shall always be 100% radiographed. Requirements as given above in clause 5.1 to 5.11 are general however in case of any conflict with welding and weld inspection specification, the welding specification shall govern.

5.12 TESTING Pressure test shall be performed as per ASME B31.3, latest edition. 5.12.1 The following items coming in line with piping shall not be subjected

to field pressure testing: a) Strainers and Filter elements. b) Pressure relieving devices such as rupture discs and

pressure relief valves. c) Locally mounted pressure gauges. d) Control valves, shutdown valves etc. e) Vessel and equipment like pumps, compressors etc. vessel

may be tested along with a piping system, provided the vessel test pressure is not less than the piping system test pressure.

f) Any other equipment designated by the Company.

5.12.1.1 All the elements which are not to be tested along with the piping shall either be blanked off during testing or spool pieces inserted during testing.

5.12.1.2 Any temporary corrosion protection coating given on

piping at manufacture’s shop / fabrication yard is to be removed at all inspection points, before final testing.

5.12.1.3 Prior to hydrotesting, vessels & piping are to be flushed

by high pressure, high Volume fresh water or inhibited sea water. However for using Inhibited sea water company approval shall be required.

5.12.1.4 All piping shall be supported as per approved drawing

before pressure testing, spring and other variable type supports shall be locked to prevent movement.

5.12.2 Following are the general requirements for testing of piping.

5.12.2.1 Test pressure shall be maintained for a sufficient length of time to permit thorough inspection of all the joints for leakage or sign of failure. The duration shall in no case be less than four (4) hours.




6-44-0503 Rev. 0 Page 8 of 13


5.12.2.2 Instrument take-off piping up to the first block valve shall be tested with the connected piping.

5.12.2.3 Lines open directly to atmosphere such as vents, drains,

safety valve discharge etc. shall be leak tested and all the joints shall be visually inspected.

5.12.2.4 Maximum allowable valve test pressure:

Seats of all valves shall not be subjected to a pressure in excess of maximum cold working pressure of the valve. Test pressure applied to valves shall not be greater than the manufacturer’s recommendation nor less than required by applicable code. Where the test pressure is greater than the allowable seat pressure, test shall be made through the open valve. 5.12.3 Hydrostatic test fluid

5.12.3.1 Fresh potable water shall be used as the testing medium for hydrostatic testing of piping in fabrication yard and at offshore, if available.

5.12.3.2 For Austenitic Stainless Steel piping, water with pH-valve not over 7 and chlorides less than 350 ppm shall only be used for hydrostatic testing. The lines shall be completely drained and dried by air immediately after the successful completion of testing.

5.12.3.3 Salt water may be permitted for testing non austenitic piping, provided the Contractor’s test procedures are approved by the Company and that they include the following:

5.12.3.4 Chemical treatment (inhibition, oxygen scavenger) to mitigate corrosion if salt water is used.

5.12.3.5 Method of isolating austenitic piping and connected equipment from contact with salt water.

5.12.3.6 Adequate steps are taken to ensure complete removal of salt water from the system after testing.

5.12.3.7 A strainer shall be installed in the line to minimize the possibility of foreign matter being introduced into the system during the pressure test and flushing operations.

5.12.3.8 Test medium shall be hydraulic oil for hydraulic service. 5.12.4 Pneumatic Testing

5.12.4.1 Pneumatic testing of instrument air, utility air, starting air and instrument gas piping shall be performed with compressed air. The test pressure shall be 110 percent of design pressure. Test duration shall be as given in 5.12.2.1.




6-44-0503 Rev. 0 Page 9 of 13


5.12.4.2 Pneumatic testing of other piping is acceptable if the test

procedure and test pressures have been approved by the Company.

5.12.4.3 When pneumatic testing at over 25 psi, a preliminary test at 25 psi shall be made to locate major leaks. Then the pressure shall be increased gradually to test pressure.

5.12.5 Test Procedure

5.12.5.1 All vents and other connections, which serve as vents, shall be open during filling so that all air is vented prior to applying test pressure to the system.

5.12.5.2 At least two nos. gauges will be installed for testing as close as possible to the highest point of the piping system & will be caliberated and checked for accuracy.

5.12.5.3 Care shall be exercised to avoid increase in pressure due to temperature variation during the test.

5.12.5.4 After completion of hydrostatic test, the pressure shall be released gradually in steps. All the vents and drains shall be kept open till the lines are fully drained. The contractor shall then dry the system by blowing compressed dry air and reinstall items removed during hydrotesting.

5.12.5.5 All testing and calibration of gauges, instrument etc. will be carried out in presence of company or its authorised representative. Record shall be made of each piping system during the testing. These records shall be prepared in tabulated forms and shall include a) Date of Test b) Identification of piping and equipment tested with

medium.

c) Test medium. d) Test Pressure.

e) Test Duration.

f) Acceptance of Test result by Company.

5.12.5.6 Testing shall be deemed as complete only after defects

noticed during testing have been rectified and retesting of the system/line has been done to the satisfaction of the company’s representative.

5.12.5.7 Temporary supports shall be provided wherever required during testing.




6-44-0503 Rev. 0 Page 10 of 13


6.0 INSTALLATION

6.1 Piping shall be installed in accordance with the approved piping drawings.

6.2 Piping installation shall include the supply and installation of supports shown in the drawing.

6.3 All lines shall be installed true and plumb except where specifically noted on the drawing.

6.4 Installation of piping shall be scheduled so that no undue strain shall be inflicted on equipment due to lack of support, dead weight or misalignment.

6.5 Piping shall be removed after installation at all rotating equipment connecting points to check the alignment with and without piping to ensure that the piping does not affect the alignment of the equipment. After checking the alignment, piping shall be re-installed.

6.6 Flange bolts shall be tightened evenly and sequentially to avoid distortion or overstressing of equipments.

6.7 During installation/fabrication, care shall be taken at all times to protect the entry of foreign materials by providing protector caps and covers or other suitable means.

6.8 Before installing prefabricated piping, the inside of the pipe shall be inspected by the contractor to ensure that all foreign mater is removed.

6.9 Stainless steel materials shall be lifted with nylon or other approved slings, which are free from dirt or ferritic particles. Under no circumstances, chain or wire ropes shall be used.

6.10 To prevent damage to valve seal and seat surfaces, valves when installed shall be left in following open/close positions:

Ball and plug valves - Fully open

Globe and gate valves - Fully closed.

7.0 REQUIREMENT OF BOLT TENSIONING & BOLT TORQUING

7.1 Hydraulic Bolt Tensioning shall be used for all flange joints in class 900# and above with bolt diameter ≥ 25 mm

7.2 Stud bolt shall be longer by one diameter to suit the length of the bolt tensioner for all sizes. Excess threads shall be protected by a threaded cap with a grease nipple.

7.3 Bolt Torquing - For all other bolts not falling in the range of hydraulic bolt tensioning.

7.4 Bolt torquing shall be applied to all the flange joints of the above said parameters.

7.5 Torque wrenches shall be used with specific value, reviewed/approved by the company.




6-44-0503 Rev. 0 Page 11 of 13


7.6 Mechanical integrity of all flange joints has to be ensured. A standard checklist for the activity along with post box-up checkup should be developed & practiced. The checklist shall include the following:

a) i) Alignment of flanges

ii) Inspection of gasket surface for possible defects such as bends or greases.

iii) Inspection of mating flanges for dirt, mechanical damage and corrosion. Use suitable solvent to clean the surface. The contact area of flanges shall be free from excess pitting and radial scratches.

iv) Ensuring the gasket is properly seated

v) Ensuring that fasteners are tightened as per tightening procedures and using specific values with well maintained tools and torque wrenches.

b) Each joint shall be boxed up and tightened by only skilled technician.

c) Ensuring right type of gaskets & fasteners etc confirming to the specifications.

d) Ensuring that the stud & nuts are free of dirt and corrosion. The studs should be straight and threads free from nicks, burr and chips etc.

e) Checking of individual joint for any leak during commissioning/ pressure testing by special tapes, soap solution or as per relevant code.

QUALITY ASSURANCE: Tool Calibration: 1. The calibration of the torque wrench and tensioner shall be

checked against manufacturer’s specifications upon receipt. Any tool that is out of calibration shall be rejected.

2. A recheck of calibration shall be made on regular basis. Any

tool found to be out of calibration shall be immediately be taken out of service for repair.

3. All flange joints secured with tool found to be defective shall

be rechecked with a properly functioning and calibrated tool.

A complete specification shall be developed for bolt tensioning and bolt torque values, line wise and size wise, stud/bolt tightening pattern, lubricants to be used and all other requirements.

8.0 PROTECTIVE COATING

Protective coating shall be applied as stated in the Specification for Protective coating.

9.0 INSULATION

Insulation shall be provided as per Specification for Insulation (6-44-0507).

10.0 SHIPPING AND HANDLING

10.1 All openings shall be protected after inspection as follows:




6-44-0503 Rev. 0 Page 12 of 13


10.1.1 Flange faces (gasket contact surfaces) shall be adequately protected by coating with a removable rust preventive and attaching a bolted or steel strapped 20 mm thick wood/plastic or metal blank. Unpainted steel blanks shall not be used where rust would discolor the coated surface of skid-assembled components. Gasket contact surfaces shall not be painted. If the surface is painted, it shall be restored to original specification condition before installation.

10.1.2 Threaded connections shall be closed with a steel/plastic pipe plug. 10.1.3 Plain or bevelled ends shall be closed with metal or a plastic cover to

protect the inside of the pipe.

10.2 Each spool piece shall be clearly marked on both ends with the line number. Marking shall not be done by stenciling the pipe. Marking shall be done by a method which will ensure that it will withstand exposure to the hazards during shipping to the job site.

10.3 Small diameter branches shall have ¼”x 1” steel plate tack welded to branch and header to prevent bending of branch pipe during transportation.

10.4 Extra caution shall be exercised when handling Cu-Ni pipe to prevent damage.

10.5 Piping materials to be shipped shall be made dry, clean and free from moisture, dirt and loose foreign material of any kind.

10.6 Piping materials shall be protected from rust, corrosion and mechanical damage during transportation, shipment and storage.

10.7 Rust preventive used on machined surfaces shall be easily removable with a petroleum solvent and the same shall not be harmful to welding.

10.8 Both ends of pipes, valves & flanges shall be protected securely with the following material

Plain end : Plastic cap Bevel end : Wood, metal or plastic cover Threaded end : Metal or plastic threaded cap Flange face : Wood or Plastic cover




6-44-0503 Rev. 0 Page 13 of 13


FIGURE-1

DIMENSIONAL TOLERANCES

Documents

6-44-0503-Rev0