Fabrication

SHOP DRAWING / PIPING SHOP FABRICATION SPECIFICATION

  1. The shop fabricator (fabrication shop engineering) shall prepare the necessary detailed shop spool drawings for fabrication from piping drawings on-site under the shop engineer’s direction. Shop spool drawings must show the details of field welds, spool number, materials, dimensions, fabrication and the applicable code and procedures.

    Shop spool drawings must identify all equipment, lines or spools connecting to that spool. The arrangement or isometric drawing must be shown as a reference.
  2. All piping drawings are dimensioned and shown in normal assembly and operating position. When specifically required, thermal expansion requirements and cold springing will be shown on drawings. Cold spring (CoS) and pre-spring (PS) are indicated on the spools with the amount added or deducted. This amount is added or deducted from the dimension, and the pipe shall be fabricated to the dimension.
  3. Pipe detail pieces shall be fabricated in accordance with the piece marks shown on the drawings, unless otherwise required for handling and/or shipping. Changes from the piece mark arrangement shown on the drawings shall require approval of the consultant.
  4. Preparation of isometric drawings by the shop fabricator is not required.

    5. 18 Handbook of oil and gas piping

  5. Piping drawings show the limits of field run piping and the locations of any field welds required between spool pieces. The shop fabricator is not to supply or fabricate that portion of the field runs.
  6. Spool piece numbers shall consist of the isometric line number followed by suffix letters, A, B, C, etc.
  7. Except for ring joint flanges, dimensions are to the centerline of the pipe and the contact face of flanges. This includes the contact face of male and female tongue and groove flanges. Ring joint flanges are dimensioned to the centerline of pipe and to the extreme face of flange and not to the contact surface of the groove.
  8. The shop fabricator (fabrication shop engineering) shall verify all spool drawings and list of materials for accuracy and compliance with the project specifications:
    1. Quantity of materials correct for the spool
    2. Description of materials correct as per project specification
    3. Pipe cut lengths
    4. All welds numbered for identification on the shop spool drawings and the documents concerned