PGI-CND-010 a SICIM Radiographic Examination Procedure.pdf

CONGO S.A.U

RADIOGRAPHIC EXAMINATION PROCEDURE

Congo marine XII Block Litchendjili Gas

Development LITCHENDJILI ONSHORE PLANT – WP5

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Bureau Veritas - Confidentiel - Toute reproduction interdite rév. 0 page 1/32

BUREAU VERITAS CONGO

B.P 687 Pointe Noire

Siège social: Immeuble EPB

Zone industrielle, Foire

Tél: (00242) 05 713 94 64/06 653 30 06

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Ind Writer Checker Approving Name Function Visa Name Function Visa Name Function Visa a

S. MBEZELE

F. WENGER

H. MADACI

EVOLUTION OF DOCUMENT Ind Date Modifications a 27/08/2014 Creation

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TABLE OF CONTENT 1. PURPOSE .......................................................................................................... 5

2. SCOPE .............................................................................................................. 5

3. DEFINITIONS & ABBREVIATIONS .................................................................... 5

3.1 Définitions ........................................................................................................ 5

3.2 Abreviations ...................................................................................................... 6

4. REFERENCE DOCUMENTS ................................................................................. 6

4.1 Bureau veritas documents .................................................................................. 6

4.2 Company general specifications .......................................................................... 6

(you can replace or add the specifications recommended) .............................................. 6

4.3 International code and standards ....................................................................... 7

4.4 Project documents............................................................................................. 7

5. RESPONSIBILITIES .......................................................................................... 8

5.1 The Quality Control Manager .............................................................................. 8

5.2 The NDT QC Supervisor ..................................................................................... 8

5.3 Operator ........................................................................................................... 8

5.4 Extent of inspection ........................................................................................... 8

6. QUALIFICATION ............................................................................................... 9

6.1 Personnel qualification ....................................................................................... 9

6.2 Procedure qualification ...................................................................................... 9

7. EQUIPMENTS ................................................................................................. 10

7.1 Source of radiation .......................................................................................... 10

7.2 Film viewer ..................................................................................................... 10

7.3 Densitometer .................................................................................................. 10

7.4 Radioprotection equipment .............................................................................. 10

8. Radiograph quality ......................................................................................... 10

8.1 Geometric unsharpness.................................................................................... 10

8.2 Density ........................................................................................................... 11

8.2.1 Blushing Density ....................................................................................... 11

8.2.2 Radiograph Density ................................................................................... 11

8.3 Image quality.................................................................................................. 11

8.4 Choice of IQI (see table below) ........................................................................ 12

8.5 Radiation source ............................................................................................. 13

8.6 Gamma ray source .......................................................................................... 13

8.7 X-ray equipment ............................................................................................. 13

9. INSTRUCTIONS .............................................................................................. 13

9.1 Surface preparation ......................................................................................... 13

9.2 Test Conditions ............................................................................................... 14

9.3 Post Weld Heat Treatment ............................................................................... 14

9.4 Number and location of radiographs ................................................................. 14

9.4.1 For vertical joints ...................................................................................... 14

9.5 Marking of weld to be radiographed .................................................................. 17

9.6 Marking films .................................................................................................. 17

9.7 Composition of the Film Cartridges ................................................................... 18

Single Film .......................................................................................................... 19

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Double Film ........................................................................................................ 19

9.8 Film quality ..................................................................................................... 19

9.9 Film size ......................................................................................................... 19

10. EXAMINATION ............................................................................................ 19

10.1 Putting the Films in Place ................................................................................. 20

10.2 Positioning of the Image Quality Indicator ......................................................... 20

10.3 Number of IQI to be kept in a radiograph .......................................................... 20

10.4 Positioning of the Equipment ............................................................................ 21

10.5 Radiation ........................................................................................................ 21

11. PROCESSING THE FILMS ............................................................................ 21

11.1 Manual Processing ........................................................................................... 21

11.2 Automatic Processing....................................................................................... 22

11.3 Positioning of the Equipment ............................................................................ 22

12. RADIOGRAPHIC EXAMINATION RECORDS ................................................. 23

13. ACCEPTANCE CRITERIA .............................................................................. 23

14. FILMS COVER MARKING ............................................................................. 24

15. REPORT ....................................................................................................... 25

16. Repair of rework ......................................................................................... 25

Appendix A – Marking of welds to be radiographed ............................................. 29

Appendix B – Marking of radiographic films ......................................................... 30

Appendix C – Composition of the cartridge .......................................................... 31

Appendix D: Image Quality Indicators ................................................................. 31

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1. PURPOSE

This procedure defines the provisions to be implemented for radiographic inspection of Congo marine XII Block Litchendjili Gas Development.

A radiographic examination is a Non Destructive examination used to find defects in compactness in the metal elements of a structure. This procedure is applied for piping work.

The principle objective of this procedure is the detection, location and evaluation of volumetric defects within the weld and the heat affected zone.

2. SCOPE

This procedure will be applied to all clients workshops and sites dedicated to the project. The inspection will cover the percentage defined in the contract.

Volumetric defaults within the weld and the heat affected zone shall be detected by Radiographic Testing.

This procedure shall be used for all butt welds, as well as branch welds having a nominal diameter not lower than 50mm. The welds of half –couplings, weldolets, etc are not required to be radiographed, being this test poorly effective on such connections.

All NDT shall also be performed after completion of all cold forming and heat treatment.

3. DEFINITIONS & ABBREVIATIONS

3.1 DEFINITIONS

COMPANY : ENI E&P

CONTRACTOR :( Enter the name of client) SICIM

SUBCONTRACTOR: BUREAU VERITAS CONGO

NDT Non Destructive Testing VT Visual Inspection RT Radiographic Testing PWHT Post Weld Heat Treatment T Thickness of the material to be checked DWSI Double Wall Single Image I.Q.I. Image Quality Indicator NDT NDT Non Destructive Testing SWSI Single Wall Single Image

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DWE Double wall exposure SWV Single wall View SWE Single wall exposure

3.2 ABREVIATIONS

Following abbreviation will be used during any calculation: • Nominal Thickness – t • Penetrated thickness – w • Object-to-film distance – b • Source size – d • Source-to-film distance – SFD • Source-to-object distance – f • Diameter - De

4. REFERENCE DOCUMENTS

4.1 BUREAU VERITAS DOCUMENTS

(Inser the contractual documents in the table)

Reference Title

PGI-CND-008 Radiographic Examination Procedure

PGI-CND-007 Piping Examination Report

4.2 COMPANY GENERAL SPECIFICATIONS

(you can replace or add the specifications recommended)

Reference Title

20377.PIP.MEC.FUN Piping Weld Examination General Requirements

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4.3 INTERNATIONAL CODE AND STANDARDS

(Add or remove the appropriate code)

Reference Title

API 650 : 11th edition, June 2007

Process Piping : Welded steel tanks for oil storage

ASME Section V Article 2 :2004 + Errata 2006

ASME Boiler and Pressure Vessel Code - NondestructiveExamination : Radiographic Examination

ASTM E94:2004

(replaced E142 in year 2000)

Standard Guide for Radiographic Examination

EN ISO 9712 Non-destructive testing - Qualification and certification of NDT personnel

ASNT –TC -1A Non-destructive testing - Qualification and certification of NDT personnel

EN 462:1994 Non-destructive testing. Image quality of radiographs. Image quality indicators (wire type). Determination of image quality value

EN 584-1:1994 Industrial Radiographic Film Classification

ASTM E1032:2006 Radiographic Examination of Weldments

ASTM E747:2004 Standard Practice for Design, Manufacture and Material Grouping Classification of Wire Image Quality Indicators (IQI) Used for Radiography

EN 462.1 Image quality of radiographs – Part 1 : Concept, Image Quality Indicators (wire type), determination of image quality value

ISO 2504 Radiography of welds and viewing conditions for films - utilization of recommended patterns of image quality indicators (IQI)

ISO 17636-1 Non-destructive testing of welds —Radiographic testing —Part 1:

X- and gamma-ray techniques with film

4.4 PROJECT DOCUMENTS

(Add specific client project documents)

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Reference Title

01303610CBQB02624 Quality Control Requirements for Construction Contractor

01303610CJPC02755 Work Method statement for fixed roof tank erection

5. RESPONSIBILITIES

5.1 THE QUALITY CONTROL MANAGER

The Quality Control Manager is responsible for verifying that the present procedure is correctly implemented. He makes sure that all of the inspection equipment are always calibrated and verified. He makes sure that the consumables are stored according to supplier or manufacturer instructions.

5.2 THE NDT QC SUPERVISOR

The NDT QC Supervisor is responsible for coordination of NDT activities on site in compliance with approved procedures, codes and standards in order to establish confidence of the quality of the inspection, the welding fabrication and its reliable performance in service. He makes sure that all of the inspection equipment are always calibrated and verified. He makes sure that the consumables are stored according to supplier instructions.

5.3 OPERATOR

The nondestructive examination technician is a competent person having been authorized to carry out this magnetic particle examination. He makes sure that all of the inspection equipment are maintained in proper working order. He makes sure that the consumables have a use-by-date compatible with the planned examinations.

5.4 EXTENT OF INSPECTION

If client doesn’t choose welds, Bureau Veritas shall have the right to select the welds to be inspected. All weld joints shall be 100% visually accepted (and documented) prior to proceed for radiographic testing. Radiographic examination shall be done as shown at the table below.

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Step of construction

Piping Class ENI E&P

All welds joints

Circumferential Joints

Branch Connections

Socket welds (fillet welds)

Seal welds (fillet welds)

VT Surface PT/MT

Volumetric RT/UT

Surface PT/MT

Volumetric RT/UT b)

Surface PT/MT

Volumetric RT a)

Shop Fabrication

4 100% 5% 5% 0 0 0 0 0 3 100%

10%

5% 10% 10%

25% 10%

10% 2 100% 25% 100%

100% 100%

1 100% 100% 100% Site assembly 4 100% 5% 5% 0 0 0 0 0

3 100% 10% 25% 100% 10% 100%

100%

100% 2 100% 100% 25% 1 100% 100% 100%

a) For operating temperatures T≥100°C, to verify the minimum gap at the socket end. b) For branches DN≥100mm and Thickness ≥15mm

6. QUALIFICATION

6.1 PERSONNEL QUALIFICATION

The Inspection will be performed and results will be evaluated by NDT inspectors qualified and certified as Level I or Level-II for the applicable method, in accordance with EN ISO 9712 EN473/CSWIP, ISO9712 or ASNT TC 1A. Radiographs will be interpreted and evaluated only by NDT Inspectors qualified and certified as Level-II (or higher) for the applicable method, in accordance with EN473/CSWIP or ISO9712.

6.2 PROCEDURE QUALIFICATION

RT Procedure Qualification shall be performed for each Technique which has to be used, with the same or similar material considering the range of dimensions, (Thickness – Diameter), to be checked. A minimum of two exposures for each configuration have to be done. Note: The radiographic Procedure shall be qualified using both, “Film Side IQI” and “Source Side IQI”. Image quality indicators shall be of the wire type as recommended by IIW/IIS 62-60 or ISO Standard and are to be placed on the source side. In case that the source side is inaccessible during production radiography, only film side penetrometers are required, but shall be marked with an "F" and the procedure shall be qualified to demonstrate that the minimum required sensitivity is achieved all through the wall thickness including the two opposite surfaces. The image quality indicators are to be clearly identified, and the sensitivity of the source side indicator is to be equal to or better than the requirements given in for "single wall technique". For "double wall technique" the IQI sensitivity shall be calculated putting the total weld thickness penetrated, i.e. two times the plate thickness plus the two weld reinforcements, at the denominator of the formula. In this case the permissible IQI values

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shall be double of those indicated (ref. EN 462). The image density corresponding to the sound weld metal shall not be less than 2.2 and not greater than 3.5, unless adequate viewing and satisfactory interpretation of higher density film are permitted by the viewing equipment.

7. EQUIPMENTS

7.1 SOURCE OF RADIATION

Gamma-rays produced by iridium 192 or maximum X-ray voltage used. The dimensions of the source shall permit the respect of the geometric unsharpness.

7.2 FILM VIEWER

The viewer must have a strong enough source of light to allow reading of the films given the required densities. The luminance of light radiographs should not be less than 30 candelas/m² with a minimum average of 100 candelas/m².

7.3 DENSITOMETER

The optic density of radiographs is measured using a calibrated densitometer.

7.4 RADIOPROTECTION EQUIPMENT

Depending on the exposure technique used, the right radioprotection equipment is installed, such as radiometer light or sound indicators, audiovisual detectors, etc. The dark room can be located on client yard. The radioactive source is stored in the BUREAU VERITAS base.

The transportation and the use of a radioactive gamma source is describe in the PGI-CND-004-a: Transport of radioactive sources by road and maritime

8. Radiograph quality

8.1 GEOMETRIC UNSHARPNESS

The following formula is used to calculate the geometric unsharpness:

��

�

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where: fg: geometric unsharpness in mm, d: distance from source side of weld or object being radiographed to the film D: Distance from source of radiation to weld or object being radiographed F: source size in mm. D and d shall be determined at the approximate center of the area of interest. The recommended maximum values of geometric unsharpness are as specified in the table below: Material Thickness, in. (mm) Ug Maximum, in.(mm) Under 2 (50) 0.020 (0.51) 2 through 3 (50-75) 0.030 (0.76) Over 3 through 4 (75-100) 0.040 (1.02) Greater than 4 (100) 0.070 (1.78) Note: Material thickness is the thickness on which the IQI is based

8.2 DENSITY

8.2.1 Blushing Density

The blushing densities must be verified on a sample of each lot on non-exposed films, then developed under the same conditions as the radiographs. Verifications should be made at regular intervals and each time a lot of films is changed. Blushing density must not exceed 0.3.

8.2.2 Radiograph Density

Optic densities measured on a radiograph taken with single film must be from 2.5 to 3.5. If a double film is exposed, the gross densities fall between 2 to 3.5 for each of the two films, the minimum density is 2. For pieces with varying thickness, when using double film, the parts of film whose density is greater than 4 are interpreted using single film. The density of the latter is between 2 and 4. Radiographic densities up to 4 may be acceptable if adequate viewing and satisfactory interpretation of itch density film are permitted by the viewing equipment.

8.3 IMAGE QUALITY

The image quality must provide good visibility of the hole or wire whose diameter is specified in the table 1 below:

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WALL THICKNESS OF WELDED ASSEMBLY (in mm)

MINIMUM PERCEPTIBLE HOLE DIAMETER (in mm)

MINIMUM PERCEPTIBLE WIRE DIAMETER (in mm)

e< 3

3 < e < 6

6 < e < 10

10 < e < 16

16 < e < 25

25 < e < 32

32 < e < 40

40 < e < 80

0.25

0.32

0.4

0.5

0.63

0.8

1

1.25

0.12

0.16

0.2

0.25

0.32

0.4

0.5

0.63

Image quality indicator sensitivity

Specimen thickness

(mm)

IQI sensitivity

(% maximum value)

3 4.0

6 3.0

12.5 2.4

25 1.7

40 1.5

50 1.3

75 1.1

100 1.0

150 0.9

When using the wire image quality indicator, the wire must at least be seen over the whole width of the weld bead. When selecting the image quality indicator, the thickness used is that of the wall of the welded element and the excess thickness on either side of the weld to be radiographed. For elliptical double wall exposure, the image quality indicator is determined by using the front and back wall thickness. In the case of a butt welded joint of two different thicknesses, and when double film is exposed, two image quality indicators, adapted respectively to each thickness, are placed on each part of joint.

8.4 CHOICE OF IQI (SEE TABLE BELOW)

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8.5 RADIATION SOURCE

RT in shop are to be preferably executed by X ray equipment. Gamma rays may be applied on yard only or on large prefabricated items. Following isotopes do not require Client’s approval: See for thin wall welds; Ir for thickness from 10mm to 19mm with qualification of the procedure test: Ir up to t=38mm; X rays for thickness above 38mm. The use of Co 60 is generally not acceptable.

WARNING – Exposure of any part of the human body to “X” or “Gamma” rays can be highly injurious to health. Wherever X-ray equipment or radioactive sources are in use, appropriate legal requirements shall be applied. National or international safety regulation(s) as well as safety instruction PGI-CND-001-a“NOTE TO RADIOLOGISTS EXPOSED TO RADIATION” shall be strictly applied when using ionizing radiation. Note: The Radiation Source will be either X-ray or Gamma-ray

RADIOPROTECTION: please refer Contingency radiographic Plan PGI-CND-006-a which match with client Ionizing Radiation Protection procedure

8.6 GAMMA RAY SOURCE

Material: Gamma-ray apparatus, with Remote control and collimator.

Radiography shall be made using a single source of gamma radiation: Iridium 192 or Se 75

Maximum current permissible Activity is 50 Ci.

The minimum wall thickness to be tested may be 10mm for Ir 192 and 5mm for Se 75, provided that an image quality conforming to minimum requirements established by the reference standard and acceptable for the company or for the Company’s Representative is obtained.

Note: For special cases, the use of a source with more than 50 Ci could be considered with prior acceptation of HSE department.

8.7 X-RAY EQUIPMENT

Material: Panoramic X-ray tube ERESCO or BALTEAU maxi 300KV and control unit or equivalent or Directional Tube X-ray Tube ERESCO or BALTEAU maxi 300 KV and control unit or equivalent.

9. INSTRUCTIONS

9.1 SURFACE PREPARATION

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The surface to be inspected shall be 100% visually inspected according to the “Visual Examination Procedure” prior to proceed with the radiographic examination.

The surface shall be free of contaminants (slag, oil, grease, scale, dirt, welding flux, spatter or other extraneous matter that may interfere with the examination) on the weld and up to at least 50 mm on each side of the weld.

9.2 TEST CONDITIONS

The final NDT tests may be performed sooner than 48 hours after completion of welding if all the following conditions are fully applied, to the satisfaction of COMPANY representative on SITE: extra low hydrogen consumables are used and proper procedures for consumables (procurement, storage, handling, baking, flux dryness, etc.) and drying of joint before welding are implemented to ensure that diffusible hydrogen is less than 5ml/100g at the welding stage. If the above requirements are not achieved to the satisfaction of COMPANY representative, no derogation shall be accepted.

9.3 POST WELD HEAT TREATMENT

Depends on weld class for P N° 3, 4 and 5 materials, RT examination shall be performed after completion of any Post Weld Heat Treatment.

9.4 NUMBER AND LOCATION OF RADIOGRAPHS

9.4.1 For vertical joints

a. For butt-welded joints in which the thinner shell plate is less than or equal to 10 mm (3/8

in.) thick, one spot radiograph shall be taken in the first 3 m (10 ft) of completed vertical joint of each type and thickness welded by each welder or welding operator. The spot radiographs taken in the vertical joints of the lowest course may be used to meet the requirements of Note 3 in Figure 8-1 for individual joints. Thereafter, without regard to the number of welders or welding operators, one additional spot radiograph shall be taken in each additional 30 m (100 ft) (approximately) and any remaining major fraction of vertical joint of the same type and thickness. At least 25% of the selected spots shall be at junctions of vertical and horizontal joints, with a minimum of two such intersections per tank. In addition to the foregoing requirements, one random spot radiograph shall be taken in each vertical joint in the lowest course (see the top panel of Figure 8-1 of API 650 code).

b. For butt-welded joints in which the thinner shell plate is greater than 10 mm (3/8 in.) but

less than or equal to 25 mm (1 in.) in thickness, spot radiographs shall be taken according to Item a. In addition, all junctions of vertical and horizontal joints in plates in this thickness range shall be radiographed; each film shall clearly show not less than 75 mm (3 in.) of vertical weld and 50 mm(2 in.) of weld length on each side of the vertical

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intersection. In the lowest course, two spot radiographs shall be taken in each vertical joint: one of the radiographs shall be as close to the bottom as is practicable, and the other shall be taken at random (see the center panel of Figure 8-1).

c. Vertical joints in which the shell plates are greater than 25 mm (1 in.) thick shall be fully

radiographed. All junctions of vertical and horizontal joints in this thickness range shall be radiographed; each film shall clearly show not less than 75 mm (3 in.) of vertical weld and 50 mm (2 in.) of weld length on each side of the vertical intersection (see the bottom panel of Figure 8-1).

d. The butt-weld around the periphery of an insert manhole or nozzle shall be completely radiographed.

9.4.2 One spot radiograph shall be taken in the first 3 m (10 ft) of completed horizontal butt joint of the same type and thickness (based on the thickness of the thinner plate at the joint) without regard to the number of welders or welding operators. Thereafter, one radiograph shall be taken in each additional 60 m (200 ft) (approximately) and any remaining major fraction of horizontal joint of the same type and thickness. These radiographs are in addition to the radiographs of junctions of vertical joints required by Item c of 8.1.2.2 (see Fig 8-1).

9.4.3 The number of spot radiographs required herein shall be applicable on a per tank basis, irrespective of the number of tanks being erected concurrently or continuously at any location.

9.4.4 It is recognized that in many cases the same welder or welding operator does not weld both sides of a butt joint. If two welders or welding operators weld opposite sides of a butt joint it is permissible to inspect their work with one spot radiograph. If the radiograph is rejected, additional spot radiographs shall be taken to determine whether one or both of the welders or welding operators are at fault.

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9.4.5 An equal number of spot radiographs shall be taken from the work of each welder or welding operator in proportion to the length of joints welded.

9.4.6 As welding progresses, radiographs shall be taken as soon as it is practicable. The locations where spot radiographs are to be taken may be determined by the Purchaser’s inspector.

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9.4.7 Each radiograph shall clearly show a minimum of 150 mm (6 in.) of weld length. The film shall be centered on the weld and shall be of sufficient width to permit adequate space for the location of identification marks and an image quality indicator (IQI) penetrameter.

9.4.8 When bottom annular plates are required by 5.5.1, or by M.4.1, the radial joints shall be radiographed as follows: (a) For double-welded butt joints, one spot radiograph shall be taken on 10% of the radial joints; (b) For single-welded butt joints with permanent or removable back-up bar, one spot radiograph shall be taken on 50% of the radial joints. Extra care must be exercised in the interpretation of radiographs of single-welded joints that have a permanent back-up bar. In some cases, additional exposures taken at an angle may determine whether questionable indications are acceptable. The minimum radiographic length of each radial joint shall be 150 mm (6 in.). Locations of radiographs shall preferably be at the outer edge of the joint where the shell plate and annular plate join.

9.4.9 The finished surface of the weld reinforcement at the location of the radiograph shall either be flush with the plate or have a reasonably uniform crown not to exceed the following values:

9.4.10 Submission of Radiographs Before any welds are repaired, the radiographs shall be submitted to the inspector with any information requested by the inspector regarding the radiographic technique used.

9.4.11 Radiographic Standards Welds examined by radiography shall be judged as acceptable or unacceptable by the standards of Paragraph UW-51(b) in Section VIII of the ASME Code.

9.5 MARKING OF WELD TO BE RADIOGRAPHED

Marking is made by the constructor on the edges of the weld to be radiographed, and it must at least include:

• The weld identification mark.

The mark defining the localization of the films according to the recommendations of client.

9.6 MARKING FILMS

Films are identified using lead numbers and letters placed on the film so as to appear on the radiograph, as indicated in Appendix B.

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Marking must comply with the requirements of the customer specifications. It must at least include the following information to ensure traceability of the welded joint :

� The RT company name

� The project name or number, the line number and weld identification number.

� The localization marks.

� The exposure positioning marks (graduated strip or marking strip enabling perfect correspondence between the radiographs and the inspected area).

� In the event of a repair, the letter ″ R″ followed by a sequential digital prefix, if required.

� In the event of a weld that was cut then repaired, the letter ″C″ followed by a sequential digital prefix, if required.

The identification system should never hinder the interpretation of the area under examination

9.7 COMPOSITION OF THE FILM CARTRIDGES

The films used are fine grain with a low or average rapidity coefficient in order to obtain good radiographic image definition. Films category shall be as per table 5 below.

Film type EN 584-1 category recognised by the Company

Type of radiographic examination related

Industrex MX 125 C3 X-Ray only

AGFA D4 C3 X-Ray only

FUJI IX80 C3 X-Ray only

INDUSTREX M C2 Gamma rays or X-Rays

AGFA D3 C2 Gamma rays or X-Rays

FUJI IX50 C2 Gamma rays or X-Rays

Nota: The film treatment shall be in accordance with the film supplier recommendations to fulfill the EN 584.1 category requirements. Sensitivity of films shall be verified by the use of wire-type Image Quality Indicator (IQI)

placed transversely to the weld on the source side, for each exposure.

In order to improve image quality, front and back lead intensifying screens are used.

The thickness ranges from 0.02 to 0.25 mm according to the type of radiation as indicated in Appendix A. The screens must be handled with care to avoid smudges, scratches or bends which could produce parasite images on the developed film.

A sufficiently thick backscatter lead screen is placed behind the cartridge to prevent backscatter radiation from reaching the film during exposure. The filtering efficiency is checked by placing, at the back of the cartridge, a lead letter ″B″, 13 mm high and 1.6 mm

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thick. The thickness of the screen (at least 2 mm) is chosen so that the image of the letter does not appear on the radiograph.

If a light image of the “B,” appears on a darker background of the radiograph, protection from backscatter is insufficient and the radiograph shall be considered unacceptable. A dark image of the “B” on a lighter background is not cause for rejection

Films used: KODAK M ‘vacupac’.

Single Film

A flexible or rigid cartridge is loaded with a film placed between two intensifying screens, the sensitive side of the screen being in perfect contact with the emulsion as indicated in Appendix A. The ensemble is placed in a light proof plastic protective sleeve. The film identification system is applied to the outside surface of the sleeve on the side of the piece to be radiographed.

Double Film

An intermediate, double sided lead screen, thickness from 0.02 to 0.10 mm, is placed between the two films according to Appendix A.

9.8 FILM QUALITY

The weld image and adjacent HAZ areas shall be free from mechanical, chemical, or other blemishes such as:

� Fogging

� Processing defect such as streaks, chemical stain or water mark

� Scratches, finger marks, crimps, dirt, static mark, tear

� Loss of detail due to poor screen / film contact

� False indication due to defective screens.

Only ultra fine grain films of a quality equal or finer than Agfa Gevaert "D4", or Kodak "M", shall be used for radiographic inspection of piping welds.

9.9 FILM SIZE

Films size shall generally be 10 x 40 cm. Smaller width films for welds without intersections may be used provided a minimum width of 15 mm of base metal appears on each side of the weld on the radiograph.

10. EXAMINATION

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10.1 PUTTING THE FILMS IN PLACE

The film must be placed in contact with the weld, on the side opposite the radiation, so that the entire area to be examined is projected on the film.

Film shall have sufficient length and shall be placed to provide at least ½ in. 13 mm of film beyond the projected edge of the weld.

Film widths shall be sufficient to depict all portion of the weld joint, including the heat affected zones, and shall provide sufficient additional space for the required penetrameter and film identification without infringing upon the area of interest in the radiograph.

The cartridges are held steady and in position during exposure by different types of supports (adhesive tape, magnets, rubber straps or wood supports, etc.) compatible with the exposure time and the shape of the piece.

Generally, the axis of the beam is directed toward the centre of the area to be examined.

If the event of an elliptical double wall exposure, for small diameter pipes, the cartridge rests on a plane in contact with the pipe opposite from the radiation (see exposure technique).

10.2 POSITIONING OF THE IMAGE QUALITY INDICATOR

The image quality of radiographs is determined by using an image quality indicator as presented in according to ASME V (Appendix D)

The image quality indicator is one way of verifying that the choice of radiographic parameters is correct. It should not be used to evaluate the dimensions of defects.

The image quality indicator must be placed on the surface of the piece on the side of the source of radiation and as close as possible to the weld.

When the wire image quality indicator is used, the wire must be placed across the weld.

When this is not technically possible, the image quality indicator is placed on the film side along with an ″F″. In this case, a comparative test must be performed on a representative piece on which an image quality indicator can be placed on the film side and another on the source of radiation side in order to determine a correspondence between the indications given by these two image quality indicators.

IQIs shall be selected and placed on the weldment in the area of interest positioning the thinnest wire toward the edge of radiograph.

10.3 NUMBER OF IQI TO BE KEPT IN A RADIOGRAPH

As per ASME B31 3:

When one or more film holders are used for an exposure, at least one IQI image shall appear on each radiograph except as outlined:

1. Tubular - single wall single image - source centred inside - 3 IQI at 120° apart under the following conditions:

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a) When the complete circumference is radiographed using one or more film holders, or;

b) When a section or sections of the circumference, where the length between the ends of the outermost sections span 240 or more deg, is radiographed using one or more film holders. Additional film locations may be required to obtain necessary IQI spacing.

2. Tubular - single wall single image - source centred inside - 3 IQI are required under the following conditions:

a) When a section of the circumference, the length of which is greater than 120 deg and less than 240 deg, is radiographed using just one film holder, or;

b) When a section or sections of the circumference, where the length between the ends of the outermost sections span less than 240 deg, is radiographed using more than one film holder.

3. In (1) and (2) above, where sections of longitudinal welds adjoining the circumferential weld are radiographed simultaneously with the circumferential weld, an additional IQI shall be placed on each longitudinal weld at the end of the section most remote from the junction with the circumferential weld being radiographed.

10.4 POSITIONING OF THE EQUIPMENT

The equipment is positioned as per to the exposure technique determined according to the position described below in 9.4.

10.5 RADIATION

The exposure time is determined by the exposure technique, the type and thickness of the materials to penetrate, and the type of film.

11. PROCESSING THE FILMS

Films are developed and processed manually or by automatic machine according to the instructions from equipment and development product suppliers. In priority, we use the automatic processing. But in case we have different problems with the automatic processor (electricity, water…), for the advancement of the project, we can use the manual processing.

11.1 MANUAL PROCESSING

Successive operations must include:

� Development in a developer bath at 20°C + 1°C, 5mn + or – 30s. � Intermediate rinsing in a water bath, or water. � Fixing in a fixing bath at a minimum of 19°C for at least 10 minutes. � Washing in running water at a minimum of 15°C for 20 to 30 minutes.

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NOTE: A wetting agent can be used to obtain uniform drying and prevent forming of water droplets on the film.

• Drying of the film in a dust-free environment.

NOTE: Drying can be sped up by placing in the films in a drying cabinet.

Baths must be changed after processing about 0.5 m2 of films per liter of developer or fixer, and at the latest two months after first use, under normal utilization and conservation conditions.

The water used for all processing operations must be clean, and may even be filtered.

11.2 AUTOMATIC PROCESSING

Processing machine used KODAK. Manufacturer instructions for the automatic machine must be followed. However, the developer temperature and time must not exceed 28°C and 3 minutes respectively.

11.3 POSITIONING OF THE EQUIPMENT

Radiographs must be read in a dark room with a suitable variable intensity viewer with spot review or masked spot review capability. The viewer shall incorporate a means for adjusting the size of the spot under examination. The viewer shall have sufficient capacity to properly illuminate radiographs with an H & D density of 4.0.

The first stage of this reading consists of checking:

� For no equivocal images resulting from handling, defective exposure, processing or other causes.

� The conformity of the image quality and the density.

Radiographs are grouped per weld, their identification marks must comply with the previously mentioned requirements.

The filming technique, the overlap between films and the length of the areas to be interpreted must provide assurance that the entire area to be examined has been radiographed.

The following parameters are incorporated in the examination and in the interpretation of compactness defects recorded when reading radiographs:

� Type of metal

� Welding process

� Type of chamfer

� Welding position.

� Geometry of the piece and dimensions.

� Exposure conditions.

A distinction should be made between real indications and accidental indications

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12. RADIOGRAPHIC EXAMINATION RECORDS

The judgements of radiographs shall be expressed by symbols having the following meaning:

A - Acceptable

NR – Weld to be repaired

NT – Weld to be cut-out

NX – Radiograph to be repeated due to film quality

RX – Radiograph to be repeated for doubts about its interpretation

EX – The examination is to be extended at the side.

13. ACCEPTANCE CRITERIA

The acceptance criteria’s complies with the specific requirements of the project. Without specific requirements, the acceptance criteria are those described on table below:

Indications shown on the radiographs of welds and characterized as imperfections are unacceptable under the following conditions, and the repair radiographed to UW-51 or, at the option of the Manufacturer, ultrasonically examined in accordance with and the standards specified in this paragraph, provided the defect has been confirmed by the ultrasonic examination to the satisfaction of the Authorized Inspector prior to making the repair. For material thicknesses in excess of 1 in. (25 mm), the concurrence of the user shall be obtained. This ultrasonic examination shall be noted under remarks on the Manufacturer’s Data Report Form: (1) any indication characterized as a crack or zone of incomplete fusion or penetration; (2) any other elongated indication on the radiograph which has length greater than:

� 1⁄4 in. (6 mm) for t up to 3⁄4 in. (19 mm) � 1⁄3t for t from 3⁄4 in. (19 mm) to 21⁄4 in. (57 mm) � 3⁄4 in. (19 mm) for t over 21⁄4 in. (57 mm)

Where t = the thickness of the weld excluding any allowable reinforcement. For a butt weld joining two members having different thicknesses at the weld, t is the thinner of these two thicknesses. If a full penetration weld includes a fillet weld, the thickness of the throat of the fillet shall be included in t. (3) any group of aligned indications that have an aggregate length greater than t in a length of 12t, except when the distance between the successive imperfections exceeds 6L where L is the length of the longest imperfection in the group; (4) Rounded Indications. Indications with a maximum length of three times the width or less on the radiograph are defined as rounded indications. These indications may be circular, elliptical, conical, or irregular in shape and may have tails. When evaluating the size of an

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indication, the tail shall be included. The indication may be from any imperfection in the weld, such as porosity, slag, or tungsten.

W= Width of defect (mm)

H= Height of defect (mm)

l = Length of defect (mm)

T= The thinnest wall thickness at the joint (mm)

L= Length of 150mm from one of the defects considered

S= Reinforcement or protrusion

Փ= Diameter of an individual defect or its greatest dimension (mm)

∑= Sum

Notes:

(1) Provided the distance from other defects is greater than 50mm (2) Provided it does not show any tails (3) Provided it is gently connected, concavity of root surface shall not reduce the

thickness of the joint, including reinforcement, to less than the thickness of the thinnest of the components being joined (T).

(4) Adjacent defects spaced less than 3 times the length of the greatest, shall be considered as a single defect with a length equal to the sum of the length of the above defects.

(5) Porosity shall not exceed that shown as acceptable in BPV Code, section VIII, division 1 appendix 4.

(6) T≤5mm: surface porosity and exposed slag inclusion are not permitted T>5mm what is specified in this table

T(mm) S(mm)

≤6.4 ≤1.6

>6.4; ≤12.7 ≤3.2

>12.7; ≤25.4 ≤4.0

>25.4 ≤4.8

14. FILMS COVER MARKING

For each radiographed weld, the relevant films shall be kept in the same cover, on which we will indicate the following:

� Name of the contractor performing the welds � Weld number � Progressive number of the films contained in the cover � Film location on the joint, for single exposure � Drawing number of the piping

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� Welder stamp � Piping Class � Pipe material, except in the case of carbon steel � Pipe diameter � Previous judgement, if any (for repeated radiographs) � Date of forwarding to the company’s Representative for the judgement.

15. REPORT

Each examination must be written up in a radiographic test report.

Any defect revealed during the interpretation must be recorded by specifying the position, type, and dimensions, as well as the decisions resulting from their evaluation with regard to the acceptance criteria.

The report shall include at least the following information, as applicable and the top of the report will be as presented in Annex F: inspection and test template in the procedure “quality Control Requirements for Construction Contractor”

� Identification (Weld N°, Manufacturer’s symbol or name, date of radiograph,…) � the dimensional map (if used) of marker placement � number of radiographs (exposures) � source size (F) � base material type and thickness, weld thickness, weld reinforcement thickness, as

applicable � source-to-object distance (D) � distance from source side of object to film (d) � film manufacturer and Manufacturer’s type/designation � number of film in each film holder/cassette � single- or double-wall exposure � single- or double-wall viewing � isotope or maximum X-ray voltage used � film brand and designation � screens used

See example report in annex 02

16. Repair of rework

All NDT required for the original weld shall be repeated and perform again

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Annex 02: Example of Report

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Appendix A – Marking of welds to be radiographed

The marks are materialized as follows: . Linear radiographs in contact or panoramic: mark ″O ″specifying the origin and an arrow indicating the positioning direction of the films. BUTT WELD OF PIPES ≥ 3″ (contact or panoramic)

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Appendix B – Marking of radiographic films

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Appendix C – Composition of the cartridge

1 - CHOICE OF INTENSIFYING SCREENS • The intensifying wall thickness screens are those integrated by the

manufacturer in the preloaded films • KODAK M 0,025 mm

2 - SINGLE FILM TECHNIQUE

3 - DOUBLE FILM TECHNIQUE

Appendix D: Image Quality Indicators

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Nom du document : ~7007852 Répertoire : C:\Users\fwenger\Documents Modèle : C:\Users\fwenger\AppData\Roaming\Microsoft\Templates\Normal.dotm Titre : CALCULATION NOTE Sujet : Auteur : [email protected] Mots clés : Commentaires : Date de création : 13/09/2014 15:35:00 N° de révision : 18 Dernier enregistr. le : 03/12/2014 18:45:00 Dernier enregistrement par : Claudine Sandrine MBEZELE Temps total d'édition : 1 199 Minutes Dernière impression sur : 08/12/2014 10:32:00 Tel qu'à la dernière impression Nombre de pages : 32 Nombre de mots : 6 720 (approx.) Nombre de caractères : 36 963 (approx.)