JOINT DEFECT

Joint Defect (Radiography Test)

POROSITY

: is the result of gas entrapment in the solidifying metal. 

SLAG INCLUSIONS

: are nonmetallic solid material entrapped in weld metal or between weld and base metal 

 

INCOMPLETE PENETRATION (IP) or lack of penetration (LOP)

: occurs when the weld metal fails to penetrate the joint. 

INCOMPLETE FUSION

: is a condition where the weld filler metal does not properly fuse with the base metal 

 

INTERNAL OR ROOT UNDERCUT

: is an erosion of the base metal next to the root of the weld.

EXTERNAL OR CROWN UNDERCUT

: is an erosion of the base metal next to the crown of the weld. 

 

EXCESS WELD REINFORCEMENT

: is an area of a weld that has weld metal added in excess of that specified by engineering drawings and codes 

 

CRACKS

: can be detected in a radiograph only when they are propagating in a direction that produces a change in thickness that is parallel to the x-ray beam

WELDING JOINT DEFECTS (RT)

Joint Defect (Radiography Test)

POROSITY

: is the result of gas entrapment in the solidifying metal.

Ciri: Tampak dalam radiography bayangan bulat hitam dengan pinggiran rata / jelas.

Standard:

1.      ANSI B31.1                                   

      Diameter max 1/3 T atau 1/8 in. (Setiap diameternya) porosity yang diizinkan adalah 3 x besar max.  pada luas 1 in. dari las.                                      

2.      ASME IX & I                                 

      Diameter max. 0.06 T untuk setiap panjang 6 in. atau 20% T atau 1/8 in. Porosity yang ada pada tebal material 1 in. besarnya tidak lebih dari 30% T atau  ¼ in. atau 5/32 in. Untuk T > 2 in. besar porosity tidak lebih besar dari 3/8 in.  

3.      API 1104                                            

      Besar bulatan porosity max. 1/8 in. atau 25% T. Cluster (lokasi porosity atau porosity terkumpul) luas max. tidak lebih dari ½ in. dan besar tiap porosity tidak lebih dari 1.6 mm pada lasan sepanjang 12 in.

      Hollow Bead :

      Pada setiap hollow bead besarnya tidak lebih dari ½ in. pada las sepanjang 12 in.

4.      API 850                                         

      Sama dengan standard ASME Sect. IX

SLAG INCLUSIONS

: are nonmetallic solid material entrapped in weld metal or between weld and base metal

Ciri: Tampak dalam radiography bayangan hitam dengan garis pinggir yang tidak beraturan

Standard:

1.   ANSI B31.1        

      Besar/panjang  max.                         ® 1/3 T                                                   

      Lebar max.                                      ® 1/3 T  (2.4mm)

      Panjang las 12 in. panjang tidak lebih 1 in.                                                         

2.   ASME IX & I                                 

      T mat.  £ 19.05 mm                         ® 6.3 mm

      T mat. 19.05 – 57.15 mm                ® 1/3 T

      T mat. ³ 57.15 mm                          ® 19 mm

3.      API 1104             

      Pada pengelasan  sepanjang 12 in.

      panjangnya tidak lebih dari 2 in. dan lebar 1.6 mm.

4.   API 850               

      Sama dengan API 1104.

INCOMPLETE PENETRATION (IP) or lack of penetration (LOP)

: occurs when the weld metal fails to penetrate the joint.

Ciri: Tampak dalam radiography jalur hitam ditengah-tengah las secara kon      tinyu atau terputus-putus dan pinggirannya lurus atau tajam

Standard:

1.      ANSI B31.1         : Tidak mengizinkan

2.      ASME IX & I      : Tidak mengizinkan

3.      API 1104             : Tidak mengizinkan

4.      API 850               : Tidak mengizinkan

INCOMPLETE FUSION

: is a condition where the weld filler metal does not properly fuse with the base metal

Ciri: Tampak dalam radiography gambar bayangan hitam bulat dan tergantung dari arah datangnya sinar.

Standard:

1.      ANSI B31.1         : No Allowable

2.      ASME IX & I      : No Allowable

3.      API 1104              : Las sepanjang 12” IF tidak lebih dari 1” (8 % dari 12 in.)                 

4.      API 850               : No Allowable

INTERNAL OR ROOT UNDERCUT

: is an erosion of the base metal next to the root of the weld.

Ciri: Tampak dalam radiography jalur hitam sepanjang las

Standard:

1.      ANSI B31.1         

Kedalaman concavity tidak lebih dari 1.6 mm atau 0.2 T. Bila pada film negatif warna concavity sama dengan base metal diijinkan.

2.      ASME I & IX                                 

      Tidak diijinkan.

3.      API 1104                                       

Maksimum 6.35 mm dengan dia luar. lebih kecil sama 69.85 mm dan dia. luar lebih besar sama dengan 60.32 mm.

4.      API 850                                         

      Tidak diijinkan.

EXTERNAL OR CROWN UNDERCUT

: is an erosion of the base metal next to the crown of the weld.

Ciri: Tampak dalam radiography bayangan hitam dikedua pinggiran las

Standard:

1.            ANSI B31.1       :       

Pada pengelasan  sepanjang 12 in. panjangnya tidak lebih dari 2 in. dan kedalamannya 0.8 mm atau 25% dari tebal metal.

2.            ASME I & IX     :       

Pada pengelasan  sepanjang 12 in. panjangnya tidak lebih dari 2 in. dan kedalamannya 0.8 mm atau 10% dari tebal metal.

3.            API 1104    :      

Pada pengelasan  sepanjang 12 in. panjangnya tidak lebih dari 2 in. atau 1/6T dan kedalamannya 0.8 mm atau 12.5% dari tebal metal.

4.            ANSI B.31.1      :       

Pada pengelasan  sepanjang 12 in. panjangnya tidak lebih dari 2 in. dan kedalamannya 0.8 mm atau 12.5% dari tebal metal.

EXCESS WELD REINFORCEMENT

: is an area of a weld that has weld metal added in excess of that specified by engineering drawings and codes

Ciri: Tampak dalam radiography jalur putih yang kontinyu atau putus-putus dalam bayangan las.

Standard:

1.                  ANSI B31.1                             

            T mat. £ 6.35 mm                      ® 1.6 mm

            T mat. 6.35 mm – 12.7 mm        ® 3.2 mm

            T mat. 12.7 mm – 25.4 mm        ® 4.0 mm

            T mat. ³ 25.4 mm                      ® 4.8 mm                                                 

2.                  ASME IX & I                           

            T mat. 1.6 mm – 2.4 mm            ® 0.8 mm

            T mat. 2.4 mm – 4.8 mm            ® 1.6 mm

            T mat. 4.8 mm – 25.4 mm          ® 2.4 mm

            T mat. 25.4 mm – 50.8 mm        ® 3.2 mm

            T mat. 50.8 mm – 76.2 mm        ® 4.0 mm

            T mat. 76.2 mm – 101.6 mm      ® 5.5 mm

            T mat. 101.6 mm – 127 mm       ® 6.3 mm

            T mat. ³ 127 mm                       ® 7.9 mm

3.                  API 1104                                 

            Sama dengan ASME Sect. IX

4.                  API 850                                   

            T mat. £ 12.7 mm                     ® Ep. Ver.2.4 mm             ®  Ep.Hor.3.2 mm

            T mat.  12.7 – 25.4 mm            ® Ep. Ver.3.2 mm             ®  Ep.Hor.4.8 mm

            T mat. ³ 25.4 mm                     ® Ep. Ver.4.8 mm             ® Ep.Hor.6.3 mm

CRACKS

: can be detected in a radiograph only when they are propagating in a direction that produces a change in thickness that is parallel to the x-ray beam

Ciri: Tampak dalam radiography seperti rambut memanjang lancip, berwarna hitam.

Standard:

1.                  ANSI B31.1   :               No Allowable

2.                  ASME IX & I:                No Allowable

3.                  API 1104       :               No Allowable

4.                  API 850         :               No Allowable

INSPECTION AND TEST PLAN (ITP)

Inspection & Test Plan (ITP)

ITP is the minimum requirement of the activities for quality control and inspection of the field construction work. This Inspection and Testing Plan outline the extent of witness inspection and its reporting.

CONFLICTING REQUIREMENTS

Should conflicts exist between this specification and other documents, the following order of precedence shall govern:

1. Scope of Work
2. Data Sheets
3. This Specification
4. Other Company Specification
5. Other Referenced Publications
6. Approved for Construction Drawings
7. Vendor’s Code

INSPECTION AND TEST PLAN REQUIREMENT

1. CONTRACTOR and/or its Vendor/Subcontractors shall prepare and execute all inspection and test. They shall conform to the above mentioned codes, standards, and project specifications.

2. CONTRACTOR and/or its Vendor/Subcontractors shall provide all inspection equipment for inspection activitie s. These activities are to assure themselves that adequate inspection personnel and back up equipment are in place in order to expedite their activities speedily so as not to impact on the construction schedule.

3. CONTRACTOR and/or its Vendor/Subcontractors shall prepare check sheets and inspection reports for carrying out the required quality control checks according to particular discipline work activities. All inspection and test reports forms shall be specific to the activity and items inspected.

4. CONTRACTOR shall also prepare a detailed inspection and test plan indicating inspection levels (spot witness, witness, hold point, etc), based on COMPANY definitions herein. The test inspection plan shall include witness/attendance requirements by COMPANY/MIGAS and/or THIRD PARTY.

5. Vendor or Subcontractor shall submit their inspection and test plan based on the CONTRACTOR’s inspection and test plan document for CONTRACTOR/COMPANY review and approval.

6.  CONTRACTOR shall generate, maintain, documented, and collate the inspection records, which is done by them or by its Vendor/Subcontractors. The system employed shall insure full tractability of records including back up in accordance to COMPANY requirements. CONTRACTOR shall submit the originals of all inspection data and other related documents to COMPANY, as required by the contract terms.

7. CONTRACTOR and its Third Party shall establish the inspection and test which are required for obtaining the SKPP (Sertifikat Kelayakan Penggunaan Peralatan) or Certificate of Worthiness to Utilize Equipment and SKPI (Sertifikat Kelayakan Penggunaan Instalasi) or Certificate of Worthiness to Utilize the Installation.

  

INSPECTION LEVEL DEFINITION

Spot Witness (SW)

Spot witness inspection is a point during construction activities where measurement, witnessing of work or inspection normally takes places. Formal written notification is not required, although oral or informal memo will normally be given. If the discipline inspector does not inspect the work at this point, the work may continue. However inspection data must be recorded, and the CONTRACTOR / Subcontractor is fully responsible to ensure that this is done before continuing the next work step.

Witness Point (W)

A witness point is a point in a construction activity where inspection must take place.  ONTRACTOR/COMPANY QC Group shall be formally notified in writing of the inspection  24 hours in advance notice is for most accurate schedule) and will normally attend the inspection. Nevertheless, CONTRACTOR needs to include schedule of inspections in weekly meetings. On a case by case basis, the inspection witnessing may be waived. In this case, inspection may proceed without attendance. However, inspection data must be recorded and submitted for review and approval. All waivers will be given in writing prior to inspection execution (jointly approved by CONTRACTOR and COMPANY).

Hold Point (H)

A Hold Point is a point in a construction activity where formal written notification is given of an inspection (24 hours in advance notice is for most accurate schedule) and work shall not proceed until the inspection is performed. Nevertheless, CONTRACTOR needs to include schedule of inspections in weekly meetings. Mandatory attendance is required.

Approval (A)

A document or drawing, which is to be submitted for approval prior to proceed the activity.

Review and Comment ( R )

A document or drawing, which is to be submitted for review/ comments.

Verification (D)

A document or drawing, which shall be submitted to COMPANY/CONTRACTOR for report/ comments.

COORDINATION

Quality Control and Inspection by CONTRACTOR

For the items marked with “ SW “ and “ W “ under column “CONTRACTOR”, the quality control and inspection will be conducted by CONTRACTOR at their own responsibility. However, COMPANY shall have the right to inspect any works done by CONTRACTOR or Vendor at any time (except for “ W ”, a written notification from CONTRACTOR is required).

Inspection Hold Point

For item marked with “ H “ under column of COMPANY and CONTRACTOR, CONTRACTOR shall notify COMPANY in writing of the inspection scheduled date and time. Witnessing shall be jointly performed by CONTRACTOR and COMPANY. CONTRACTOR can not proceed the next work step activity until the inspection and measurement or test has been witnessed and approved by all attending parties.

Notification of Inspection

CONTRACTOR shall give a written notification to COMPANY for attending the inspection/testing.

Document Approval

For item marked with “ A “ under column “COMPANY”, CONTRACTOR shall submit documents, drawing, etc. to COMPANY. For item marked with “ A “ under column “CONTRACTOR”, Vendor shall submit documents, drawing, etc. to CONTRACTOR for approval. Inspection shall not be conducted before COMPANY approves the required documents.

Document Review

For item marked with “ R “ under column “COMPANY”, CONTRACTOR will submit documents, drawing, etc. to COMPANY for review / comment. For item marked with “ R “ under column “CONTRACTOR”, Vendor shall submit documents, drawing, etc. to CONTRACTOR for review / comment.

Document Verification

For item marked with “ D “ under column “COMPANY”, CONTRACTOR shall submit documents, drawing, etc. to COMPANY for a report and/ or comments (if required). CONTRACTOR shall accommodate COMPANY’s comments (if any). For item marked with “ D “ under column “CONTRACTOR”, Vendor shall submit documents, drawing, etc. to CONTRACTOR for verification and review and or report.

STORAGE TANK (API 650)

Storage Tank (API 650)

Shop Fabrication Inspection

1        Material Receiving Inspection Report

Ø      Check visual (free of lamination & damage).

Ø      Check certificate (keaslian, Heat No & Plate No).

Ø      Check dimensional (Length, Thickness, Width & Diameter).

2        Marking

Ø      Check dimensional marking.

Ø      Check transfer heat no.

3        After Cutting

Ø      Check dimensional.

Ø      Check traceability (Heat No & Plate No).

Ø      Check Stamp Marking.

4        Rolling

Ø      Check visual (free of damage).

Ø      Check edge preparation.

Ø      Check Rolling radius.

5        Painting

Ø      Check material painting (batch no, self life, brand).

Ø      Check Ambient Condition (surface & whether).

Ø      Check DFT.

Field Erection Inspection

6        Dimensional Inspection

1        Peaking banding

Peaking measured using a horizontal sweep board 36 inch (900 mm) long. Tolerance of peaking shall not exceed ½ inch (12.7 mm).

Banding measured using a straight edge vertical sweep board 36 inch (900 mm) long. Tolerance of peaking shall not exceed ½ inch (12.7 mm).

2        Roundness

Ø      Check roundness at 0°, 45°, 90°, 135°, 180°, 225°, 270°, 325°

Ø      Radius measured at 1 foot above the bottom corner weld shall not exceed the following tolerance:

Diameter	Tolerance
< 40	±½”
40 – 150	±¾”
150 – 250	±1”
≥250	±1¼”

3        Plumbness

Ø      Check at 0°, 45°, 90°, 135°, 180, 225°, 270°

Ø      The plumbness of the top of shell relative to the bottom of the shell not exceed 1/200 of the total tank height.

Ø      The out of plumbness in one shell plate (single course) shall not exceed 1/250 of the course height.

7        Visual

      Visual examinations shall be carried out during all stages of fabrication to ensure that the completed fabrication meets COMPANY satisfaction and approval with particular attention being paid to the following:

A weld shall be acceptable by this kind of inspection if the conditions are fulfilled :

Ø      The weld has no crater cracks or other surface cracks.

Ø      The maximum acceptable undercutting is 1/64 inches of the base  metal for vertical joints, and 1/32 inches maximum for horizontal joints. For the welds that attach nozzles, manholes, clean-out opening, and permanent attachments, no undercutting exceeds 1/64 inches.

Ø      The frequency of surface porosity in the weld does not exceed one  cluster (one or more pores) in any 4 inches of length, and the diameter of each cluster does not exceed 3/32 inches.

Welds that fail to meet the criteria given in paragraph above, shall be reworked prior to hydrostatic testing as follows :

Ø      Defects shall be removed by mechanical means or thermal  gouging  processes.

Ø      If the resulting thickness is less than minimum required as per hydrostatic test design conditions, re-welding is required.

Ø       The repair weld shall be visually examined for defects prior to reexamined by radiography.

8        NDT

1        Oil leak test

media solar, method spray, temperature ambient, holding period 4 hours.

2        Vacuum box test

            Vacuum testing shall conduct as follows:

Ø      Vacuum testing is conveniently performed by means of a metal testing box, 6 inches wide x 30 inches long, with a glass window in the top. The open bottom is sealed against the tank surface by a sponge-rubber gasket. Suitable connections, valves, and gauges should be provided.

Ø      Approximately 30 inches of the seam under test is brushed with a soap solution or linseed oil. The vacuum box is placed over the coated section of the seam,  and a vacuum is applied to the box. Bubbles or foam produced by air sucked through the welded seam will indicate the presence of porosity in the seam.

Ø      A vacuum can be drawn on the box by any convenient method, such as connection to a gasoline or diesel-motor intake manifold or to an air ejector or special vacuum pump.

Ø      Vacuum box tested using a test pressure at least 3 psi gauge or as specified on Company specification.

3        Radiography test

Ø      Radiographic examination method shall be in accordance with the ASME  section V, Article 2.

Ø      Radiographic inspection is required for shell butt weld, annular-plate butt welds, and flush-type connection with butt welds.

Ø      Inspection by radiographic method is not required for roof-plate or bottom-plate welds, for welds joining roof plates to top angle, the top angle to the shell plates, shell plates to bottom plates, or appurtenances to tanks.

Ø      Number and location of radiographic shall minimum as specified on API Standard 650, Section 6. Vendor shall submit proposal of number and location of radiographic to CONTRACTOR/COMPANY for review and approval.

Ø      The radiographers shall be certified by the manufacturer meeting the requirement as outlined by ASNT Recommended Practice SNT-TC-1A and its supplement.

Ø      Vendor shall submit the radiography test result to CONTRACTOR/COMPANY for review and approval. The penetrameter image as result of radiography shall clearly enough for visual examination on a radiograph viewer. The acceptance criteria of radiographs result shall be judged as specified on ASME Section VIII Div. 1, par. UW-51 (b).

Ø       Repairing defective welds shall be done by chipping or melting out the defects from one or both side of joint, as required, and proceed with re-welding. All repaired welds are subject to be re-tested as specified above.

4        Penetrant test

Ø      Liquid penetrant examination shall be performed in accordance to ASME Section V, Article 6.

Ø      Magnetic particle examiner shall meet the requirements on API Standard 650 par. 6.4.3.

Ø       The acceptance criteria and repair of defects shall be per ASME Section VIII, Division 1, Appendix 8, Par. 8-3, 8-4, and 8-5.

5        Ultrasonic test

Ø      Ultrasonic examination method shall be in accordance with ASME Section V,  article 5.

Ø      Ultrasonic examiner shall be qualified in accordance with as specified on API Standard 650 par. 6.3.3.

Ø       The acceptance criteria and repair of defects shall be per ASME Section VIII, Division 1, Appendix 12, Par. 12-3 and 12-4.