the is.us.319.22 tofd certification scheme rev1 _rev1_12-1… · the is.us.319.22 tofd...

The IS.US.319.22 TOFD certification scheme Rev1

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Requirements for TOFD certification

The IS.US.319.22 certification scheme

Date: 12 October 2010 Revision: 1


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Members of the reviewer committee:

GRTgaz

Arnaud FROISSARD Jean-Pierre LEGRANDAIS Institut de Soudure

Sylvie BITTENDIEBEL Didier FLOTTE Institut de Soudure Industrie

Eli ABITAN Jérôme BEIGE Alain BLAYA Jean-Pierre BOURDEAUD’HUI Christian BRACQUART Michel CENCE Daniel CHAUVEAU Serge DEMONTE Eric GOYHENECHE Bruno KOWALSKI Pascal ROUSSEL

Technip

Séverin CHAPUIS Michel DUSCH Etienne SOUTIF Total EP/TDO/TEC

Jean-Michel AUBERT Sébastien BARROIS Isabelle BOUGET Henri GODINOT Jean-Christophe GUELY Jean-Michel RIVEREAU Henri ROMAZZOTTI Total EP/TDO/EXP/MIN

Olivier GILLIERON

Total RM/RAF/TEC

Charles LENEVE TIGF

Pascal LLEBOT

Contact : Daniel CHAUVEAU - Tél. +33 1 49 90 37 32 – [email protected]


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CONTENT

2 - MINIMUM REQUIREMENTS 5

2.1 - Training 5

2.2 - TOFD Experience 5

3- EXAMINATION CONTENT FOR LEVEL 2 6

3.1 - General content for UT-TOFD level 2 6

3.2 - Complementary certification content for specific component inspection 7

4 - EXAMINATION CONTENT FOR UT-TOFD LEVEL 3 7

4.1 “Grand fathering” period 7

4.2 Level 3 examination further to the transition period 7

5 - RE-EXAMINATION 8

6 - RENEWAL 9

7 - RECERTIFICATION 9

8 – EXAMINATION ORGANISATION 9

REFERENCES 10

MANDATORY APPENDIX 1: DEFINITION OF TEST SAMPLES FOR THE GENERAL UT-TOFD CERTIFICATION (G-MODULE) 11

MANDATORY APPENDIX 2: DEFINITION OF TEST SAMPLES FOR COMPLEMENTARY CERTIFICATION ON SPECIFIC COMPONENT 12

MANDATORY APPENDIX 3: DEFINITION OF TEST SAMPLES FOR THE P MODULE 13

MANDATORY APPENDIX 4: DEFINITION OF TEST SAMPLE FOR THE T MODULE 14


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1 - Scope This document prescribes the specific requirements and procedures whereby Institut de Soudure recommends to set-up an Ultrasonic Time of Flight Diffraction (TOFD) certification for testing ferritic steel butt welds on Pressure Vessel and Tubular Components.

The certification scheme (Figure 1) described in this document is available only to holders of current, valid ultrasonic testing certification (according to EN 473 [1] or equivalent). This scheme is in accordance with the TOFDPROOF requirements as mentioned in [2] & [3] and satisfy the request made in the frame of the ALTERX project [4]

Candidates will be required to demonstrate that they meet the following minimum supplementary training and certification requirements before being allowed to take TOFD examinations.

The general UT-TOFD certification (called G module) for level 2 is only valid for the inspection of butt welds on flat components (15 mm ≤ t ≤ 50 mm) or having a great curvature radius (OD ≥ 1 000 mm). The G module is satisfactory to inspect common butt welds as met on pressure vessels in the specified range of thicknesses and to detect and size corrosion in parent metal of these components.

When specific components have to be examined, complementary certification content shall be added. They are called:

C module for detection and sizing of corrosion on parent metal and welds in component having complex geometry,

H module for butt weld inspection having heterogeneous material such as clad components,

P module for butt weld inspection on tubular components such as girth or longitudinal welds on pipelines, piping systems…

T module for butt weld inspection on thick components (t > 50 mm), Xi … Xn possible modules for other specific components or applications to be

defined.

Figure 1: Certification scheme

EN473 or equivalent

G module

C H P T Xi Xn


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The required complementary module shall be specified by end user in their specification. Examples of recommended modules association are given here after.

Example of component to inspect Module Butt welds on pressure vessel 15 mm ≤ t ≤ 50 mm G Girth welds on pipe 6 mm ≤ t < 15 mm G & P Butt welds on thick (t > 50 mm) clad welds on pressure vessels G & H & T Detect and size corrosion in component having complex geometry G & C

2 - Minimum Requirements

2.1 - Training The minimum training duration is in accordance with the following:

Level 2 5 Days (35 Hours)

Level 3 3 Days (24 Hours)

From one to three more days per complementary module are recommended.

2.2 - TOFD Experience Before attempting TOFD certification, the minimum TOFD experience duration shall be in accordance with the following:

Level 2 6 Months

Level 3 3 Months

Level 3 (direct) 9 Months


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3- Examination Content for level 2 3.1 - General content for UT-TOFD level 2 All candidates attempting this examination must hold level 2 certification in ultrasonic weld testing according to EN 473 or equivalent. All candidates are required to attempt an examination comprising the following parts: Part 1: Theory This part deals with the application of the Ultrasonic Time of Flight Diffraction technique for testing welds on the given specific sector. Fifteen multiple-choice questions shall be answered in 45 minutes and five questions with a narrative answer (50 minutes maximum). The minimum pass mark is 70%. Part 2: Practical examination This part comprises:

a) Assembly and calibration of TOFD data acquisition equipment. This part of the examination involves the setting up of the equipment followed by a calibration exercise to check the test system performances. At the discretion of the examiner, this part may include oral questions. Candidates shall then be required to demonstrate that they are familiar with the data display, computer and data handling and storage methods used by the TOFD system in use. If this part of the examination is satisfactory, the candidate may proceed to the remainder. If not, he may repeat the exercise once. If it is still unsatisfactory, the examination will be discontinued.

b) Collecting and storing test data on 2 flat samples as defined in Appendix 1.

NDT instructions, including information and test parameters will be provided to all candidates.

c) Interpreting and reporting the recorded scan file(s). Display the results in an indicated format, showing the location and size of flaws present in the weld and applying acceptance levels (appropriate documentation shall be provided to the candidate, especially for corrosion defect criteria).

The total time allowed for the practical examination is 4 hours (2 hours per sample including calibration, interpretation and reporting). The minimum pass mark for the practical part is 70% per sample tested (failure to detect and report a non acceptable discontinuity in any sample will result in failing this part of the examination). Part 3: Image interpretation from files Five TOFD files shall be interpreted and sentenced according to recognised standards or specifications (appropriate documentation shall be provided to the candidate).


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The maximum time allowed is two hours. The minimum pass mark for the image interpretation is 70% (failure to interpret a non-acceptable indication will result in failing this part of the examination).

3.2 - Complementary certification content for specific component inspection When specific components have to be examined, complementary certification content shall be added on the following principles:

- one or two supplementary samples representative of the specific component to examine shall be added to the practical examination (see Appendix 2 to 4)

- five TOFD images representative of the specific features that can be met on the specific component, seven multiple-choice questions and 3 questions with a narrative answer concerning the specific component shall be added.

- writing a detailed TOFD instruction to be applied by a field level 2 in accordance with a provided code, standard or specification. The maximum time allowed is one hour and 30 minutes. The minimum pass mark for the NDT instruction is 70% (failure to produce an acceptable NDT instruction, will result in failing this part of the examination).

4 - Examination content for UT-TOFD level 3

4.1 “Grand fathering” period Before organising a UT TOFD level 3 examination, a transition period during which candidates can be named by the employer is possible, provided that all the following criteria are met:

the duration of the transition period shall not exceed 3 years from the first date of examination organised for a UT TOFD level 2.

the candidate shall have a UT level 3 according to EN 473 or equivalent, the candidate shall have proven and documented experience (theoretical and

practical) of TOFD application on welds. Further to the 3 years period, the candidate shall pass the UT TOFD level 3 exam.

4.2 Level 3 examination further to the transition period All candidates attempting this examination must hold level 3 certification in ultrasonic testing in accordance with EN 473. The certification is valid whatever the type of component to be examined.


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All candidates will be required to attempt an examination comprising the following parts: Part 1: Theory Ten multiple-choice questions (30 mn) and ten questions (100 mn) with a narrative answer or with TOFD images interpretation covering: the theory of Ultrasonic Time of Flight Diffraction testing of welds, pressure vessels, pipes, clad component, and in service damaged component shall be answered within 130 minutes. The minimum pass mark is 70%. Part 2: Practical examination UT-TOFD level 3 candidates who do not hold, or have not held UT-TOFD level 2 will be required to successfully complete the general practical examination described in 3.1 above. Part 3: Images interpretation UT-TOFD level 3 candidates who do not hold, or have not held, UT-TOFD level 2 will be required to successfully complete, in addition of the following, the general practical examination described in 3.1 above. The maximum time allowed is 2 hours. The minimum pass mark for the NDT instruction is 70% (failure to interpret a non-acceptable indication, will result in failing this part of the examination). Part 4: Preparing a detailed TOFD procedure The candidate will be required to produce a comprehensive Ultrasonic Time of Flight Diffraction test procedure embodying an NDT instruction for a specific weld configuration to a provided specification, standard or code. The maximum time allowed is 4 hours (appropriate documentation shall be provided to the candidate). The minimum pass mark is 70%.

5 - Re-examination

A candidate failing for reasons of unethical behaviour shall wait at least 12 months before reapplying. A candidate who fails to obtain the pass grade for any examination part (part 1 to 4 for level 2 and 3), may be re-examined twice in the failed part(s), provided that the re-examination takes place not sooner than one month, unless further training acceptable to this certification scheme is satisfactorily completed, nor later than twelve months after the original examination. A candidate failing all permitted re-examination shall apply for and take the examination in accordance with the procedure established for new candidates.


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6 - Renewal

UT-TOFD level 2 and level 3 certification is initially valid for a period of 5 years. Renewal is examined based on the candidate file as described in EN 473.

7 - Recertification

Upon completion of each second period of validity (every ten years), the certified individual may be recertified for a new period of five years, on the basis of the following requirements:

UT-TOFD level 2 certificate holders seeking re-certification will be required to undertake only the practical examination detailed in clause 3.1 for G-module and 3.2 for the complementary module.

The minimum pass mark for re-certification is 70% for each sample. Only one retest of failed re-certification examinations is permitted. For complementary module UT-TOFD level 2 candidates must pass the NDT instruction writing part in order to re-certify.

UT-TOFD level 3 certificate holders seeking re-certification either:

- successfully complete a written examination including twenty questions as a minimum on the application of a wide range of components (at least five questions of which shall require narrative answers which demonstrate an understanding of TOFD techniques and related codes and standards (appropriate documentation shall be provided to the candidate). The minimum pass mark is 70%

- meet the requirements of a structured credit system (as per Annex C EN 473)

8 – Examination organisation

The examination is organised under the responsibility of a UT-TOFD level 3 examiner. The examiner shall not have trained the candidate during the last 5 past years. The candidate is allowed to bring his TOFD equipment after agreement from the level 3 examiner. During the certification examination, if several candidates are examined at the same time, each candidate shall have a different sample available. Each sample shall have different types and numbers of discontinuities.


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References [1] EN 473 Non Destructive Testing – Qualification and certification of NDT personnel – General principles [2] TOFDPROOF European project (contract n° G6RD-01-00626., 2002 - 2005) - “Effective application of TOFD method for weld inspection at the manufacturing stage of pressure vessels” [3] Main issues of the European TOFDPROOF project – D.CHAUVEAU, D.FLOTTE, C.BOUCHER – ECNDT 2006 http://www.ndt.net/article/ecndt2006/doc/Tu.3.3.1.pdf [4] Projet ALTERX - Contrôle en fabrication des soudures de tuyauteries : guide des alternatives à la gammagraphie à l’Ir 192.


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Mandatory Appendix 1: Definition of test samples for the general UT-TOFD certification (G-Module) Two flat samples shall be tested:

the first one is a plate having a corrosion or a simulated corrosion (15 mm ≤ thickness (*) ≤ 50 mm),

the second one is a welded flat sample (15 mm ≤ thickness ≤ 50 mm).

The welded sample shall contain at least one non acceptable discontinuity according to acceptance level standard such as EN 15617.

(*) Thicker component can be used provided the examination is limited to one slice of the total thickness


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Mandatory Appendix 2: Definition of test samples for complementary certification on specific component

A sample representative of the specific component for which the certification is required shall be provided.


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Mandatory Appendix 3: Definition of test samples for the P module

For butt weld inspection on pipelines, the following is mandatory:

a flat sample with a V bevel (10 mm ≤ thickness ≤ 12 mm). The sample shall contain at least five discontinuities (acceptable and non acceptable according to acceptance level standard such as EN 15617). Three different types of discontinuities according to EN 14751 (EN ISO 10863) shall be implemented. (at minimum a non acceptable discontinuity shall be implemented in HAZ and at a depth less than 5 mm from the face opposite the scanning face

a section of pipe with a full girth weld (6 mm ≤ thickness ≤ 10 mm) shall be tested. This sample shall contain at least five discontinuities (acceptable and non acceptable according to a recognised acceptance level standard or specification). At least, two areas with geometrical imperfections shall also be implemented.


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Mandatory Appendix 4: Definition of test sample for the T module A flat sample shall be tested (thickness ≥ 55 mm).

Each sample shall contain at least five discontinuities (acceptable and non acceptable according to acceptance level standard such as EN 15617). The discontinuities shall be located at different levels in depth in order to verify the capability of the operator to use the appropriate set-up and checking without having the “support” from the lateral wave. Three different types of discontinuities according to EN 14751 (EN ISO 10863) shall be implemented. (at minimum a non acceptable discontinuity shall be implemented in HAZ and at a depth less than 5 mm from the face opposite the scanning face)

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