Pipeline Fabrication


Pipeline Fabrication and Installation Activities includes pipe bending, welding, pipeline string, pipeline lowering etc. :

Welding of a Pipe Line

Welding of a Pipe Line


  1. Pipeline Dump Sites
  2. Pipeline Welding
  3. Pipeline Bending
  4. Pipeline Lowering
  5. Pipeline Stringing

Pipeline Dump Sites

Acquiring of land and development of dump site

  1. Grading of land.
  2. Providing temporary fencing, barrier gate, guard room and security.
  3. Providing internal roads (WBM) for trailer movement and area lighting with DG Set.
  4. Providing sand rows for stacking of coated pipes.

 Handling of Coated Pipes

  1. Adequate cranes with padded hooks for unloading / loading of coated pipes in trailers.
  2. Stacking of coated pipes on sand rows.
  3. Holiday check and visual check including gauge plate pull test before despatch to site.

Pipeline Welding

      1. Welding Procedure Specification (WPS) to be followed for the welding to be qualified and the Procedure qualification record (PQR) is approved before start of welding.
      2. Approved brand of electrodes are used for welding.
      3. Physical properties of the weld produced by an electrode shall not be less than minimum value of base metal.
      4. Electrode qualification and batch record are maintained.
      5. Each pipe shall be thoroughly checked internally & externally for visual defect/ damage and cleaned internally by compressed air blowing.
      6. Damaged end shall be cut and re-bevelled with beveling machine.
      7. All new bevels shall be 100% dye penetrant /MPI tested and Ultrasonically tested for any lamination.
      8. Use of internal clamp is mandatory for pipe dia.> 10” except tie in joints, fitting etc. In such case external clamps are used.
      9. Each joint shall bear an identification number which shall be followed for NDT.
      10. The number of welders, and welding sequence, speed etc. should be similar to that of adopted in approved welding procedure.
      11. Radiography examination of 100 % girth weld is carried out.
      12. Weld shall meet the requirement of API 1104.
      13. In addition 100% ultrasonic inspection is required for critical weld joints i.e. tie in, welding of valves etc. joints which have not undergone pressure testing i.e. GOLDEN TIE-Ins.
      14. Repair is limited to maximum 30% of the weld length.
      15. Weld containing cracks shall be cut and re-bevelled to make a joint.
      16. Destructive testing of weld joints are done for 0.1% of the total numbers of welds completed.

Pipeline Welding – Fill and Cap – Complete Setup :

Pipeline Welding – 42 Inch Tie-In :

Pipeline Welding – A Day On The Hot Pass :

Pipeline Bending

  1. For changes in vertical and horizontal alignment, pre-fabricated cold field bends are provided.
  2. Over bends are made in manner that centre of bend bears the highest point of trench bottom.
  3. Sag bends shall fit the bottom of the trench.
  4. Side bends shall have specified clearance to the outside wall of the trench.
  5. The radius of cold field bends shall not be more than 40 times the dia of the pipe (for 18” and above) and 30 times the dia of pie (for 18” below).
  6. Pipes with longitudinal welds are bent a way that weld lies in the plane passing through the neutral axis of bend.


Pipe Bending :

Pipe Bending Machine 6″- 24″ :

Pipe line Equipment and Bending Machinery :

Pipeline Lowering

  1. Lowering shall commence after inspection of trench.
  2. Trench bottom shall be free from pipe supports, stones, roots, debris, stakes, and rigid material.
  3. Padding shall be provided in rocky/ murram area.
  4. Lowering shall commence as soon as possible after completion of joint coating.
  5. Before lowering in, complete check by a full circle holiday detector for pipe coating and field joint coating at 15 KV is carried out (Speed 300mm /sec).
  6. Any damage shall be repaired.
  7. Support/ skid points shall be thoroughly checked.
  8. The pipeline must be laid without interruption for the whole or the length of section available.
  9. Ends of the lowered pipeline section shall be closed with night cap to prevent ingress of water, mud etc.

Laying Pipeline in Swamps

  1. Two methods may be considered for the installation of pipelines in swamps:
    1. The flotation method, where the pipeline is laid from a barge moving through a channel cut along the right of way.
    2. The push-pull method, where the ditch is dug by    a    lightweight    track-driven machine and the pipeline, fitted with buoyancy tanks if necessary, is pulled along the ditch and sunk. This method is preferred in environmentally sensitive areas.

 Offshore Pipeline Laying

  1. Several offshore installation methods can be envisaged, depending on the pipeline characteristics (diameter, length, waterdepth) and the availability of suitable equipment: conventional pipelaying (S-curve), reeling, towing following assembly onshore (on-bottom, off-botom, mid-depth and surface), J-laying.
  2. Conventional pipeline barges should have sufficient tensioner capacity to allow one tensioner to be kept on standby.
  3. Stingers should not be longer than 60 metres.
  4. Equipment shold be tested on mobilisation should include as a minimum the anchor wincher, the pipe tensioners, the abandonment and recovery winches, the pipe straighteners and all navigation/positioning equipment as applicable.

 Youtube Videos

lowering in nebraska- transcanada song –original :

Pipeline Welding – Lowering In :

Lowering In Pipe on the Pipeline :

hak lowering pipe 3 :

Pipeline Stringing

  1. Stringing shall be done after blasting and trenching when ROU is in rocky area.
  2. Coated pipes shall be strung on approved soft earth/sand filled bag and wedge in such a way that bottom of the coated pipe remain above ground.
  3. Pipes shall be supported at minimum two location.
  4. Pipe number, Heat Number, Coat number and length shall be transferred and recorded in serial order.

Youtube Videos

Stringing Pipeline :

Stringing Pipeline :

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