PTT Exploration and Production Public Company Limited PTTEP Engineering General Specification (Production Asset and Operation Support Group) Standard Radiographic Examination Specification Document No: 10012-STD-6-INT-003-R00 September 2017 Radiographic Examination Specification 10012-STD-6-INT-003-R00 Revision History Rev R00 Description of Revision New Document Date 10-Oct-17 September 2017, R00 History UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 TABLE OF CONTENTS 1.0 INTRODUCTION...................................................................................................... 1 2.0 PURPOSE ............................................................................................................... 1 3.0 SCOPE .................................................................................................................... 1 4.0 RESPONSIBLE ACTION PARTIES ......................................................................... 2 5.0 DEFINITIONS .......................................................................................................... 4 5.1 5.2 5.3 Language .................................................................................................................................. 4 Terminology .............................................................................................................................. 4 Common Acronyms .................................................................................................................. 4 6.0 REFERENCES......................................................................................................... 5 6.1 6.2 PTTEP Internal References ...................................................................................................... 5 External references ................................................................................................................... 5 7.0 REQUIREMENT....................................................................................................... 6 7.1 7.2 7.3 7.4 Written Procedure ..................................................................................................................... 6 Equipment ................................................................................................................................. 6 Execution .................................................................................................................................. 6 Safety ........................................................................................................................................ 7 8.0 INTERPRETATION .................................................................................................. 8 8.1 8.2 Evaluation ................................................................................................................................. 8 Acceptance Criteria .................................................................................................................10 9.0 DOCUMENTATION ............................................................................................... 11 9.1 9.2 Recording of Indications .........................................................................................................11 Reporting .................................................................................................................................12 10.0 APPENDICES ........................................................................................................ 14 Appendix 1. Appendix 2. Technique ....................................................................................................................14 Various Radiographic Technique .............................................................................32 September 2017, R00 TOC UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 1.0 10012-STD-6-INT-003-R00 INTRODUCTION This Standard (STD) details the Radiographic Testing (RT) which is a nondestructive test method based on the principle of preferential radiation transmission, or absorption. Areas of reduced thickness or lower density transmit more, and therefore absorb less, radiation. The radiation which passes through a test object will form a contrasting image on a film receiving the radiation. This method is used to inspect materials for hidden flaws by using the ability of short wavelength electromagnetic radiation to penetrate various materials. Either a high energy X-ray machine or a gamma radiation source (Ir-192, Co-60 or in rare cases Cs-137) can be used as a source of photons. There are other methods (e.g. neutron radiography) but this specification details the general principles for industrial X- and gamma radiography for flaw detection purposes using film techniques. It is only applicable to metallic products and materials. 2.0 PURPOSE The purpose of this document is to provide details of methodology for performing of implementation of "Radiographic Test" to detect the imperfection that open to surface of nonporous materials and welds (both metallic and non – metallic). All NDE personnel must perform his/her work by strictly complying with the detail in this document. This document has been written for the performing of Radiographic Test for platform structure, pipeline, process piping, facility equipment and etc. 3.0 SCOPE This document has been written to be the procedure to perform RT in role of Maintenance and Inspection for in-services upstream processing facilities. Radiographic Test is the NDE method which is selected to verify the integrity of equipment by detection of surface and subsurface discontinuities in all common engineering materials. A further advantage is that the developed film serves as an excellent permanent record of the test if the film is stored properly away from excessive heat and light. The disadvantage of radiographic testing is that it may not detect those flaws which are considered to be more critical (e.g., planner cracks and incomplete fusion) unless the radiation source is preferentially oriented with respect to the flaw direction. Further, certain test object configurations (e.g., branch or fillet welds) can make both the performance of the testing and interpretation of results more difficult. However, experienced test personnel can obtain radiographs of these more difficult geometries and interpret them with a high degree of accuracy. The limitation of this test method is the need for access to both sides of the test object (one side for the source and the opposite for the film). September 2017, R00 Page 1 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 4.0 10012-STD-6-INT-003-R00 RESPONSIBLE ACTION PARTIES 4.1 CUSTODIAN Keep this document updated as necessary and address regulatory changes and policy improvements. Ensure that effectiveness and efficiency of the procedures are assessed and audited on an annual basis, at minimum. Review and/or update this document when necessary, 3 years maximum interval. Provide technical recommendations and/or justifications in case of any deviations from the requirements of this document. 4.2 INSPECTION SUPERVISOR Control work quality by complying with approved written procedure. Review NDE report Perform his/her work in scope of TA1 at worksite. 4.3 TECHNICAL AUTHORITY 1 (TA1) Management of the standards and mandatory practices pertaining to his/her expertise under the scope of Maintenance and Inspection. Provision of technical advice to the ASSET Managers and Corporate functions under the scope of Maintenance and Inspection. Performing and/or Reviewing Risk Assessments that are performed under the scope of Maintenance and Inspection. Providing advice on proposed changes or deviations of practices under the scope of Maintenance and Inspection. Assessment and appointment of lower levels of TA under the scope of Maintenance and Inspection. Ensure provision of practices and knowledge share across ASSETs and Projects under the scope of Maintenance and Inspection. 4.4 TECHNICAL AUTHORITY 2 (TA2) Provision of technical advice to the ASSET Managers and Corporate functions. Performing and/or Reviewing Risk Assessments that are performed. Providing advice on proposed changes or deviations. To arbitrate technical disputes between TA1s and ASSET Manager. September 2017, R00 Page 2 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 Assessment and appointment of TA1. To act TA1 in case TA1 is not identified. To provide support and mentoring of TA1's. Maintain Standards and mandatory practices pertaining to their expertise. Ensure the best practices and knowledge sharing across ASSETs and Projects. To be a member of the audit team to assure ASSET and Project compliance with Company Standards. To perform verification activities for the Safety Critical Elements. Responsible for ensuring that Corporate-Level Codes, Standards and Recommended Practices are in place, approved, up-to-date and maintained. To act as ASSET/Project level (TA1) for an individual ASSET where and ASSET/Project level (TA1) is not justified, not available or where there is currently no individual suitable to fulfil the TA1 position within that asset. 4.5 NDE PERSONNEL All NDE personnel who perform his/her work for NDE shall be qualified by complying with minimum requirement of COMPANY standard (document no. 10008-STD-6-INT001-R00), ASNT Recommended Practice SNT-TC-1A and/or approved equivalent by the applicable code. The examination shall be performed by NDE personnel qualified to at least level II. However, NDE level I shall be qualified to assist NDE Level II in performing specific calibrations, specific tests and specific evaluations and record test results following specific written instructions provided under the direct supervision from NDE level II. All NDE personnel of CONTRACTOR who are provided to perform his/her work is required to show their resume and qualification certificates in advance to the TA1 and TA2 prior to mobilization. All NDE personnel of CONTRACTOR who are provided to perform his/her work must be approved before testing. His/her competency shall be reviewed and approved by demonstration competency under witness by TA1 and TA2 prior to mobilization. It is the objective of all NDE personnel to detect and report all significant flaws in accordance with the relevant codes and specifications. All NDE personnel shall perform his/her NDE work in accordance with approved written procedure. September 2017, R00 Page 3 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 5.0 10012-STD-6-INT-003-R00 DEFINITIONS A number of different terms are commonly used to describe the work stages, processes, and approvals which take place during the early stages of a development. This can often be a source of confusion so the following section is intended to show the PTTEP preferred terminology as used in this document. 5.1 LANGUAGE In this document, the words should and shall have the following meanings: May Indicates a possible course of action Must Indicates a mandatory and regulatory course of action. Shall Indicates a mandatory course of action. Should Indicates a preferred or logical course of action. 5.2 TERMINOLOGY Terminology Description Approval The authorization in writing given by the COMPANY to the Contractor to proceed the work without releasing in any way the Contractor from any of his obligations to conform with the technical specifications, requisitions, etc. The words “Approve”, “Approved” and “Approval” shall be construed accordingly Company PTT Exploration and Production Public Company Limited and affiliates. 5.3 COMMON ACRONYMS Set out below in alphabetical order are common acronyms as found within this document: NDE Nondestructive Examination RT Radiographic Testing September 2017, R00 Page 4 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 6.0 REFERENCES 6.1 PTTEP INTERNAL REFERENCES 10012-STD-6-INT-003-R00 Internal documents applicable to this document are indicated in the table below. Document Number 10008-STD-6-INT-001-R00 6.2 Document Title Inspection and Testing Requirements EXTERNAL REFERENCES Codes, standards and regional legislation applicable to this document are indicated in the table below. Document Number Document Title AWS D1.1 Structural Welding Code ASME B 31.3 Process Piping ASME B31.4 Pipeline Transportation Systems for Liquids and Slurries ASME B31.8 Gas Transmission and Distribution Piping Systems ASME V Nondestructive Examination Article 2 ASME VIII div. 1 and 2 Pressure Vessel Design Code ASTM E 94 Standard Guide for Radiographic Examination ASTM E 747 Standard Practice for Design, Manufacture and Material Grouping Classification of Wire Image Quality Indicators (IQI) Used for Radiology ASTM E 1025 Standard Practice for Design, Manufacture, and Material Grouping Classification of Hole-Type Image Quality Indicators (IQI) Used for Radiology ASTM E 1255 Standard Practice for Radioscopy ASTM E 1416 Standard Practice for Radioscopic Examination of Weldments API 1104 Welding of Pipelines and Related Facilities API 5L Specification for Line Pipe BS EN ISO 11699-1:2011 Non-destructive testing. Industrial radiographic film. Classification of film systems for industrial radiography September 2017, R00 Page 5 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 7.0 REQUIREMENT 7.1 WRITTEN PROCEDURE 10012-STD-6-INT-003-R00 Radiographic Test shall be performed in accordance with a written procedure which shall as a minimum, contain the requirements listed in “ASME section V, Article 2”, ASTM E 94, ASTM E 747 and ASTM E 1025 (with regards to type of construction codes and standards). Change of the essential variable shall require requalification of the written procedure by demonstration. All changes of essential or nonessential variables from those specified within the written procedure shall require revision of, or an addendum to, the written procedure. The testing shall be done by approved procedure, demonstration under witness by Company. 7.2 EQUIPMENT Radiographic Test materials are intended to include film, intensifying screens, Image Quality Indicator (IQI) design, facilities for viewing of radiographs and sources shall be complied with in ASME section V. 7.3 EXECUTION The execution of Radiographic Testing is comprised of test arrangement, surface preparation, identification of radiographs, marking, overlap of films, Image Quality Indicator, technique, calibration and examination shall be performed by strictly complying with approved written procedure. The conditions and types of imperfection that this NDE method is able to apply are shown as below; All or most standard techniques will detect this imperfection under all or most conditions; o Service-Induced Imperfections: Abrasive Wear (Localized), Corrosion – Pitting and Erosion o Welding Imperfections: Burn Through, Excessive / Inadequate Reinforcement, Inclusions (Slag / Tungsten), Incomplete Penetration, Misalignment, Porosity, Root Concavity and Undercut o Product Form Imperfections: Cold Shuts (Castings), Inclusions (All Product Forms) and Porosity (Castings) One or more standard technique(s) will detect this imperfection under certain conditions; o Service-Induced Imperfections: Corrosion – General / Uniform, Fatigue Cracks, Hot Cracking and Stress-Corrosion Cracks (Transgranular) o Welding Imperfections: Cracks and Incomplete Fusion September 2017, R00 Page 6 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification o 10012-STD-6-INT-003-R00 Product Form Imperfections: Bursts (Forgings), Cracks (All Product Forms), Hot Tear (Castings) and Laps (Forgings) 7.4 SAFETY All testing carried out in accordance with this procedure shall comply with the relevant safety documents regarding health and safety at work, fire hazards, electrical safety, toxic materials, safety and working in confined / restrictive compartments. Testing material shall be used in accordance with the manufacturer’s instructions. WARNING: Exposure of any part of the human body to X-rays or gamma-rays can be highly injurious to health. Wherever X-ray equipment or radioactive sources are in use, appropriate legal requirements must be applied. 7.4.1 GENERAL PRACTICES Personnel handling radioactive isotopes and/or X-ray equipment shall be licensed by the appropriate governmental competent authorities. Radio isotopes must never be carried on aircraft except in extreme emergency. The pilot must be made aware of the nature and strength of the cargo. Radio isotopes must be stored in flame proof shielded containers. The storage area must be marked with the UN “trefoil” I.D, and access limited to authorised personnel only. Relevant lifting certificate for the container such as third party visual inspection certificate, proof load test certificate and NDT reports are required. All radiography must be carried out under either a hot or cold work permit (depending on the technique) and additional complementary work permit. The permit will indicate (in addition to the normal precautions and etc.) the type and strength of the source (e.g. Iridium 192, 750 Gbq). Radiation strength must not exceed 925 Gbq (GigaBecquerels) or 25 Ci (Curie) per source. Barrier must be erected around the storage area at the point where the dose rate is equal to or less than 2.5 µSv/hr (micro Sievert / hour). Barricades must be erected to a safe distance as calculated by the radiographer using the strength and purpose of the equipment. The recognised safe distance is regarded as where the maximum allowable dose rate is 7.5 µSv/hr (micro Sievert / hour). The barrier should be black and yellow striped tape or flagging with trefoil sign. Warning signs must be posted, flashing lights are advisable, and an authorised stand by person in place. A PA announcement should be made before and after the job. September 2017, R00 Page 7 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 Film badges must be worn by all operatives. A radiation survey meter must be positioned. Dosimeter with valid calibration certificate must be available in event of suspected contamination. 7.4.2 TRANSPORTATION The following precautions must be taken: The source must be in its custom made inner container which is inside a metal locked box with the UN trefoil symbol clearly visible. The key for the box will be with the radiographer. Certification for the source giving type and strength will be carried with the load. A load recovery package will be attached. This will consist of a secure rope of strength sufficient for 3 x the load which will be at least 2 times (200%) the maximum depth of the sea around the jobsite and during transportation. A floating buoy with flashing light MUST be attached. 8.0 INTERPRETATION 8.1 EVALUATION Evaluation of Radiographic Testing is comprised of; 8.1.1 QUALITY OF RADIOGRAPHS All radiographs shall be free from mechanical, chemical, or other blemishes to the extent that they do not mask and are not confused with the image of any discontinuity in the area of interest of the object being radiographed. Such blemishes include, but are not limited to: Fogging; Processing defects such as streaks, watermarks, or chemical stains; Scratches, finger marks, crimps, dirtiness, static marks, smudges, or tears; False indications due to defective screens. 8.1.2 8.1.2.1 RADIOGRAPHIC DENSITY DENSITY LIMITATIONS The transmitted film density through the radiographic image of the body of the appropriate hole IQI or adjacent to the designated wire of a wire IQI and the area of interest shall be 1.8 minimum for single film viewing for radiographs made with an X-ray source and 2.0 minimum for radiographs made with a gamma ray source. For composite viewing of multiple film exposures, each film of the composite set September 2017, R00 Page 8 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 shall have a minimum density of 1.3. The maximum density shall be 4.0 for either single or composite viewing. A tolerance of 0.05 in density is allowed for variations between densitometer readings. 8.1.2.2 DENSITY VARIATION General. If the density of the radiograph anywhere through the area of interest varies by more than minus 15% or plus 30% from the density through the body of the hole IQI or adjacent to the designated wire of a wire IQI, within the minimum/maximum allowable density ranges specified in 8.1.2.1, then an additional IQI shall be used for each exceptional area or areas and the radiograph retaken. When calculating the allowable variation in density, the calculation may be rounded to the nearest 0.1 within the range specified in 8.1.2.1. With Shims. When shims are used with hole-type IQIs, the plus 30% density restriction of (a) above may be exceeded, and the minimum density requirements of 8.1.2.1 do not apply for the IQI, provided the required IQI sensitivity of 8.1.3.1 is met. 8.1.3 8.1.3.1 IQI SENSITIVITY REQUIRED SENSITIVITY Radiography shall be performed with a technique of sufficient sensitivity to display the designated hole IQI image and the 2T hole, or the essential wire of a wire IQI. The radiographs shall also display the IQI identifying numbers and letters. If the designated hole IQI image and 2T hole, or essential wire, do not show on any film in a multiple film technique, but do show in composite film viewing, interpretation shall be permitted only by composite film viewing. 8.1.3.2 EQUIVALENT HOLE-TYPE SENSITIVITY A thinner or thicker hole-type IQI than the required IQI may be substituted, provided an equivalent or better IQI sensitivity, as shown below, is achieved and all other requirements for radiography are met. Equivalent IQI sensitivity is shown in any row which contains the required IQI and hole. Better IQI sensitivity is shown in any row which is above the equivalent sensitivity row. If the required IQI and hole are not represented in the table, the next thinner IQI row may be used to establish equivalent IQI sensitivity. Hole-Type Designation 2T Hole Designation Equivalent Hole-Type Designations 1T Hole 4T Hole 10 15 5 12 17 7 15 20 10 17 25 12 20 30 15 25 35 17 30 40 20 35 50 25 September 2017, R00 Page 9 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 40 60 30 50 70 35 60 80 40 80 120 60 100 140 70 120 160 80 160 240 120 200 280 140 8.1.4 EXCESSIVE BACKSCATTER 8.1.4.1 BACKSCATTER RADIATION A lead symbol “B,” with minimum dimensions of 1⁄2 in. (13 mm) in height and 1⁄16 in. (1.5 mm) in thickness, shall be attached to the back of each film holder during each exposure to determine if backscatter radiation is exposing the film. 8.1.4.2 EXCESSIVE BACKSCATTER If a light image of the “B,” as described in 8.1.4.1 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. 8.1.5 EVALUATION TA1 and TA2 shall be responsible for the review, interpretation, evaluation, and acceptance of the completed radiographs to assure compliance with the requirements of approved written procedure and the referencing Code Section. As an aid to the review and evaluation, the radiographic technique documentation required by 9.1.3.1 shall be completed prior to the evaluation. The radiograph review form required by 9.1.3.2 shall be completed during the evaluation. The radiographic technique details and the radiograph review form documentation shall accompany the radiographs. Acceptance shall be completed prior to presentation of the radiographs and accompanying documentation to the Inspector. 8.2 ACCEPTANCE CRITERIA Acceptance standards are primarily based upon the length, width and size of the actual indication. Acceptance criteria shall be in accordance with the construction code. September 2017, R00 Page 10 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 9.0 DOCUMENTATION 9.1 RECORDING OF INDICATIONS 10012-STD-6-INT-003-R00 9.1.1 NONREJECTABLE INDICATIONS Nonrejectable indications shall be recorded as specified by the referencing Code Section for Company baseline and further reference. 9.1.2 REJECTABLE INDICATIONS Rejectable indications shall be recorded. As a minimum, the type of discontinuity, location and extent (length or diameter or aligned) shall be recorded. 9.1.3 EXAMINATION RECORDS 9.1.3.1 RADIOGRAPHIC TECHNIQUE DOCUMENTATION DETAILS The following information shall be provided as minimum; Identification as required for System of Identification. o The system shall be used to produce permanent identification on the radiograph traceable to the contract, component, weld or weld seam, or part numbers, as appropriate. In addition, the Manufacturer’s symbol or name and the date of the radiograph shall be plainly and permanently included on the radiograph. This identification system does not necessarily require that the information appear as radiographic images. In any case, this information shall not obscure the area of interest. The dimensional map (if used) of marker placement. Number of radiographs (exposures) X-ray voltage or isotope type used Source size Base material type and thickness, weld thickness, weld reinforcement thickness, as applicable Source-to-object distance Distance from source side of object to film 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 9.1.3.2 RADIOGRAPH REVIEW FORM The following information shall be provided as minimum; September 2017, R00 Page 11 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 List of each radiograph location The information required in 9.1.3.1, by inclusion or by reference Evaluation and disposition of the material(s) or weld(s) examined Identification (name) of the representative who performed the final acceptance of the radiographs 9.2 Date of evaluation REPORTING For each radiograph, or set of radiographs, a test report shall be made giving information on the radiographic technique used, and on any other special circumstances which would allow a better understanding of the results. Details concerning form and contents should be specified in special application standards or be agreed on by the contracting parties. If inspection is carried out exclusively to this standard then the test report shall contain at least the following information: Name of the testing company Unique report number Object Material Stage of manufacture Nominal thickness Radiographic technique and class System of marking used Test arrangement and film position plan, if required Radiation source, type and size of focal spot and equipment used Selected film systems, screens and filters Tube voltage and current or source activity Time of exposure and source-to-film distance Type and position of image quality indicator Reading of I.Q.I and minimum film density Conformance to this International Standard Any deviation from agreed standards Name, certification and signature of the responsible person(s) September 2017, R00 Page 12 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 Date of exposure and report The test report shall then contain the test results, including a detailed description and location of the indications (with a sketch where appropriate) and a statement as to whether they meet the acceptance criteria. September 2017, R00 Page 13 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 10.0 APPENDICES Appendix 1. 1) Technique Classification of Radiographic Techniques Radiographic techniques are divided into two classes: Class A: Basic Techniques. Class B: Improved Techniques. Class B technique will be used when Class A may be insufficiently sensitive. Better techniques, compared with Class B, are possible and may be agreed between the contracting parties by specification of all appropriate test parameters. The choice of radiographic technique shall be agreed between the parties concerned. If, for technical reasons, it is not possible to meet one of the conditions specified for the Class B, such as the type of radiation source or the source-to-object distance f, it may be agreed between the parties that the condition selected may be that specified for Class A. The loss of sensitivity shall be compensated by an increase of minimum density to 3.0 or by using a higher contrast film system. Because of the better sensitivity compared to Class A, the test sections may be regarded as examined within Class B. 2) General 2.1 Test Arrangement The test arrangement consists of the radiation source, test object and the film or film-screen combination in cassette and depends on the size and shape of the object and the accessibility of the area to be tested. Generally, one of the arrangements illustrated in Section 2.1.1 to Section 2.1.7 should be used. The beam of radiation shall be directed at the middle section under examination and shall be normal to the surface at that point, except when it is known that certain flaws are better revealed by a different alignment of the beam. When radiographs are taken in a direction other than normal to the surface, this shall be indicated in the test report. Double-wall techniques are acceptable only if single wall techniques are not practical. September 2017, R00 Page 14 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification September 2017, R00 t f 1 2 material thickness t b source-to-object distance f distance between the film and the surface of the object nearest the source film 2 b radiation source with an effective optical focus size d 1 Arrangement 1: Single-wall penetration – Object with plane walls KEY 2.1.1 10012-STD-6-INT-003-R00 Page 15 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 2.1.2 10012-STD-6-INT-003-R00 Arrangement 2: Single-wall penetration – Object with curved walls – Source off- September 2017, R00 t f 1 2 distance between the film and the surface of the object nearest the source b b material thickness t N.B. This arrangement is preferred to Arrangement 4 source-to-object distance film 2 f radiation source with an effective optical focus size d 1 KEY center on concave side – Film on convex side Page 16 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version September 2017, R00 UNCONTROLLED when printed, visit PTTEP Intranet for latest version radiation source with an effective optical focus size d film source-to-object distance material thickness distance between the film and the surface of the object nearest the source 2 f t b 2 b t f t 2 1 N.B. One advantage of this technique is that the whole circumference may be radiographed in one exposure. This arrangement is preferred to Arrangements 2, 4 or 5. f b 2.1.3 1 KEY 1 2 Radiographic Examination Specification 10012-STD-6-INT-003-R00 Arrangement 3: Single-wall penetration – Object with curved walls – Source located centrally Page 17 of 33 Radiographic Examination Specification 2.1.4 10012-STD-6-INT-003-R00 Arrangement 4: Single-wall penetration – Object with curved walls – Source on September 2017, R00 t f 1 2 material thickness t b source-to-object distance f distance between the film and the surface of the object nearest the source film 2 b radiation source with an effective optical focus size d 1 KEY convex side – Film on concave side Page 18 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version 1 2 radiation source with an effective optical focus size d film source-to-object distance material thickness distance between the film and the surface of the object nearest the source Because the source is close to the upper wall, flaws should not be evaluated in this wall. 1 2 f t b N.B. 2.1.5 f t KEY Radiographic Examination Specification 10012-STD-6-INT-003-R00 Arrangement 5: Double-wall penetration – Single-wall evaluation – Source and film outside September 2017, R00 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Page 19 of 33 b 1 2 N.B. Flaws in the upper wall may be evaluated. For some applications the radiation beam might be used at a different angle (i.e. not perpendicular to the centre of the film). distance between the film and the surface of the object nearest the source b source-to-object distance f material thickness film 2 t radiation source with an effective optical focus size d 1 KEY b 2.1.6 September 2017, R00 UNCONTROLLED when printed, visit PTTEP Intranet for latest version f t Radiographic Examination Specification 10012-STD-6-INT-003-R00 Arrangement 6: Double-wall penetration – Double-wall evaluation – Source and film outside Page 20 of 33 Radiographic Examination Specification 2.1.7 10012-STD-6-INT-003-R00 Arrangement 7: Single-wall penetration – Object with plane or curved walls of different thicknesses or materials – Two films with the same or material thickness distance between the film and the surface of the object nearest the source t b 2 source-to-object distance film 2 f radiation source with an effective optical focus size d 1 1 b KEY different speeds t f 2.2 Surface Preparation In general, surface preparation is not necessary, but where surface imperfections or coatings might cause difficulty in detecting defects, the surface shall be ground smooth or the coatings shall be removed. Unless otherwise specified radiography shall be carried out after the final stage of manufacture, e.g. after grinding or heat treatment. September 2017, R00 Page 21 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 2.3 Identification of Radiographs Symbols shall be affixed to each section of the object being radiographed. The images of these symbols shall appear in the radiograph outside the region of interest where possible and shall ensure unequivocal identification of the section. 2.4 Marking Permanent markings on the object to be examined shall be made in order to locate accurately the position of each radiograph. Where the nature of the material and / or its service conditions does not permit permanent marking, the location may be recorded by means of accurate sketches. 2.5 Overlap of Films When radiographing an area with two or more separate films, the films shall overlap sufficiently to ensure that the complete region of interest is radiographed. This shall be verified by a high-density marker, on the surface of the object which will appear on each image. 2.6 Image Quality Indicator Standard IQI Design: IQIs shall be either the hole type or the wire type. Hole-type IQIs shall be manufactured and identified in accordance with the requirements or alternates allowed in ASTM E 1025. Wire-type IQIs shall be manufactured and identified in accordance with the requirements or alternates allowed in ASTM E 747, except that the largest wire number or the identity number may be omitted. ASME standard IQIs shall consist of detail in ASME V, Article 2. those in ASME V, Table T233.1, for hole type and those in Table ASME V, T-233.2, for wire type. Alternative IQI Design: IQIs designed and manufactured in accordance with other national or international standards may be used provided the requirements of either (a) or (b) below, and the material requirements of ASME V, T-276.1, are met. (a) Hole Type IQIs. The calculated Equivalent IQI Sensitivity (EPS), per ASTM E 1025, Appendix X1, is equal to or better than the required standard hole type IQI. (b) Wire Type IQIs. The alternative wire IQI essential wire diameter is equal to or less than the required standard IQI essential wire. 3) Recommended Techniques 3.1 Choice of X-Ray Tube Voltage & Radiation Source 3.1.1 X-Ray Equipment To maintain good flaw detection sensitivity, the X-ray tube voltage should be as low as possible. The maximum values of tube voltage versus thickness are given in Figure 1. September 2017, R00 Page 22 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 Figure 1: Maximum X-ray voltage for X-ray devices up to 500 kV as function of penetrated wall thickness 3.1.2 Other Radiation Sources The permitted penetrated thickness ranges for gamma ray sources and X-ray equipment above 1 MeV are given in Table 1. Table 1: Penetrated thickness range for gamma ray sources and X-ray equipment with energy from 1 MeV and above for steel, copper and nickel-base alloys Radiation source 170 Penetrated thickness, w (mm) Test Class A Test Class B w5 w5 1 w 15 2 w 12 10 w 40 14 w 40 20 w 100 20 w 90 40 w 200 60 w 150 Tm Yb1) 75 Se2) 192 Ir 60 Co X-ray equipment with energy 30 w 200 50 w 180 from 1 MeV to 4 MeV X-ray equipment with energy 50 w 80 w from 4 MeV to12 MeV X-ray equipment with energy 80 w 100 w > 12 MeV 1) For aluminum and titanium the penetrated material thickness is 10mm w 70mm for Class A and 25 w 55 for class B 2) For aluminum and titanium the penetrated material thickness is 35mm w 120mm for Class A 169 September 2017, R00 Page 23 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 On thin steel specimens, gamma rays from 192Ir and 60Co will not produce radiographs having as good a defect detection sensitivity as X-rays used with appropriate technique parameters. However because of the advantages of gamma ray sources in handling and accessibility, Table 1 gives a range of thicknesses for which each of these gamma ray sources may be used when the use of X-rays is not practicable. For certain applications wider wall thickness ranges may be permitted, if sufficient image quality can be achieved. In cases where radiographs are produced using gamma rays, the set-up time required to position the source shall not exceed 10% of the total exposure time. 3.2 Film Systems and Screens For radiographic examination, film system classes shall be used in accordance with BS EN ISO 11699-1:2011. For different radiation sources the minimum film system classes are given in Tables 2 and 3. When using screens, good contact between film and screen is required. This may be achieved by using vacuum-packed films or by applying pressure. For different radiation sources, Tables 2 and 3 show the recommended screen materials and thicknesses. Other screen thicknesses maybe used provided it is agreed between the contracting parties provided the required image quality is achieved. September 2017, R00 Page 24 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification Table 2: 10012-STD-6-INT-003-R00 Film system classes and metal screens for the radiography of steel, Cu- and Ni-based alloys Penetrated wall Radiation source thickness w (mm) X-ray potentials ≤ 100 kV X-ray potentials > 100 kV to 150 kV X-ray potentials > 150 kV to 250 kV Film system class1) Class A Class B Class A Class B None or up to 0.03mm front and back screens of lead T3 169Yb w<5 170Tm w≥5 T3 X-ray potentials > 250 kV to 500 kV TYPE AND THICKNESS OF METAL SCREEN w ≤ 50 T2 T2 T2 T3 T3 w > 50 Up to 0.15mm front and back screens of lead 0.02mm to 0.15mm front and back screens of lead None or up to 0.03mm front and back screens of lead 0.02mm to 0.15mm front and back screens of lead 0.02mm to 0.3mm front and back screens of lead 0.1mm to 0.3mm front screen of lead2) 0.02mm to 0.3mm back screen of lead 0.1mm to 0.2mm front and back screens of lead2) 0.02mm to 0.2mm 0.1mm to 0.2mm front front screen of lead screen of lead2) 0.02mm to 0.2mm back screen of lead 75Se T3 T2 192Ir T3 T2 T3 T3 0.25mm to 0.7mm front and back Screens of steel or copper3) T3 T2 0.25mm to 0.7mm front and back screens of steel or copper3) T2 T2 T2 60Co X-ray equipment with energy from 1 MeV to 4 MeV w ≤ 100 w > 100 w ≤ 100 w > 100 w ≤ 100 X-ray equipment with energy above 4 MeV to 12 MeV 100 < w ≤ 300 w > 300 w ≤ 100 X-ray equipment with energy > 12 MeV T3 T2 100 < w ≤ 300 w > 300 T3 T3 Up to 1mm front screen of copper, steel or tantalum4) Back screen of copper or steel up to 1mm and tantalum4) up to 0.5mm T2 Up to 1mm front screen of tantalum5) No back screen T3 Up to 1mm front screen of tantalum5) Up to 0.5mm back screen of tantalum 1) Better film system classes may also be used 2) Ready packed films with a front screen up to 0.03mm may be used if an additional lead screen of 0.1mm is placed between the object and the film 3) In Class A also 0.5mm to 2mm screens of lead may be used 4) In Class A lead screens 0.5mm to 1mm may be used by agreement between Company and Contractor 5) Tungsten screens may be used by agreement September 2017, R00 Page 25 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification Table 3: 10012-STD-6-INT-003-R00 Film system classes and metal screens for aluminum and titanium Radiation source Film system class1) Class A Class B X-ray potentials ≤ 150 kV X-ray potentials > 150 kV to 250 kV X-ray potentials > 250 kV to 500 kV Type and thickness of intensifying screen None or up to 0.03mm front and up to 0.15mm back screens of lead 0.02mm to 0.15mm front and back screens of lead T3 T2 0.1mm to 0.2mm front and back screens of lead 0.02mm to 0.15mm front and back screens of lead 0.2mm front screens2) and 0.1mm to 0.2mm back screens of lead 169Yb 75Se 1) Better film system classes may also be used 2) Instead of 0.2mm lead, a 0.1mm screen with an additional filter of 0.1mm may be used 3.3 Alignment of Beam The beam of radiation shall be directed to the center of the area being inspected and shall be normal to the object surface at that point, except when it can be demonstrated that certain inspections are best revealed by a different alignment of the beam. In this case an appropriate alignment of the beam can be permitted. 3.4 Reduction of Scattered Radiation Scattered radiation reaching the film is an important cause of reduced image quality, particularly with X-rays between 150 kV and 400 kV. Scattered radiation can originate from both inside and outside the specimen. In order to minimize the effect of scattered radiation, the area of the field of radiation shall be masked, so that the beam is limited to the area of interest. This is normally done by masking the primary cone of the radiation beam, either with a physical cone or with a diaphragm on the tube head. The film shall also be shielded from radiation scattered from other parts of the specimen or from objects behind or beside the specimen. This can be done by using a back intensifying screen of extra thickness or by using a sheet of lead behind the film screen combination; this extra sheet may by used inside the cassette or placed immediately behind the cassette. Depending on the set-up, typical lead thicknesses are in the range of 1 mm. to 4 mm. If the upper edge of a thick specimen is within the radiation field, a method of reducing undercutting scatter is generally necessary. The following diagram shows two typical methods. September 2017, R00 Page 26 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Film 10012-STD-6-INT-003-R00 Lead sheet Radiographic Examination Specification Methods of reducing the effect of scattered radiation With 192Ir and 60Co radiation sources or in case of edge scatter, a sheet of lead can be used as a filter of low energy scattered radiation between the object and the cassette. The thickness of this sheet is 0.5 mm to 2 mm dependent on the penetrated thickness. With X-rays of 6 MV energy or more used without back intensifying screens, shielding against scattered radiation is not necessary, unless there is scattering material close behind the film. In general, with X-rays between 150 kV and 400 kV and with gamma rays, if a beam restrictor cannot be used, such as when panoramic exposures are being made, the exposures shall be made in as large a room as possible, so that extraneous scatter is attenuated by distance; the September 2017, R00 Page 27 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 specimens, whenever possible, shall be well above floor level and the floor near the specimen shall be covered with lead. The effect on scattered radiation shall be checked for each arrangement by a lead letter B (with a height of minimum 10 mm and a thickness of minimum 1.5 mm) placed immediately behind each cassette. If the image of this symbol appeared on the radiograph, it shall be rejected. If the symbol is invisible the radiograph is acceptable and sufficiently protected against scattered radiation. 3.5 Source-To-Object Distance The minimum source-to-object distance fmin depends on the source size d and on the objectto-film distance b. The distance f, shall, where practicable, be chosen so that the ratio of this distance to the source size d, i.e. -f/d, is not below the values given by the following equations: For Class A: f 7. 5 b 2 3 d (1) For Class B: f 15 b 2 3 d (2) If the distance b < 1.2 t the dimension b in equations (1) and (2) and Figure 2 shall be replaced by the nominal thickness t. For determination of the source-to-object distance, fmin, the nomogram in Figure 2 may be used. The nomogram below is based on equations (1) and (2). In Class A, if planar imperfections have to be detected the minimum distance fmin shall be the same as for Class B in order to reduce the geometric unsharpness by a factor of 2. In critical technical applications of crack-sensitive materials more sensitive radiographic techniques than Class B shall be used. If the radiation source could be placed centrally inside the object to be radiographed (Arrangement 3) to achieve a more suitable beam direction and to avoid a double wall technique (Arrangements 5 and 6), this method shall be preferred. The reduction in minimum source-to-object distance should not be greater than 50%. September 2017, R00 Page 28 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 Figure 2: Monogram for determination of minimum source-to-object distance fmin in relation to of object-to-film distance and the source size 3.6 Maximum Area for A Single Exposure The ratio of the penetrated thickness at the outer edge of an evaluated area of uniform thickness to that at the center beam shall not be more than 1.1 for Class B and 1.2 for Class A. The densities resulting from any variation of penetrated thickness should not be lower than those indicated in Section 3.7 and not higher than those allowed by the available illuminator, provided suitable masking is possible. 3.7 Density of Radiographs Exposure conditions should be such that the total density of the radiograph (including base and fog density) in the inspected area is greater than or equal to that given in Table 4. September 2017, R00 Page 29 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification Table 4: 10012-STD-6-INT-003-R00 Density of radiographs Class Density1) A ≥ 2.02) B ≥ 2.32) A measuring tolerance of ± 0.1 is permitted. May be reduced by special agreement between the contracting parties to 1.5. May be reduced by special agreement between the contracting parties to 2.0. High densities may be used with advantage where the viewing light is sufficiently bright in accordance with Section 3.9. In order to avoid unduly high fog densities arising from film ageing, development or temperature, the fog density shall be checked periodically on a non-exposed sample taken from the films being used, and handled and processed under the same conditions as the actual radiograph. The fog density shall not exceed 0.3. Fog density here is defined as the total density (emulsion and base) of a processed, unexposed film. When using a multi film technique with interpretation of single films the density of each film shall be in accordance with Table 4. If double film viewing is requested the density of one single film shall not be lower than 1.3. The acceptable geometric unsharpness shall be within the limitations given in the table 5 or applicable standard. Table 5: No Geometric Unsharpness Limitations Material Thickness, in (mm) Ug , Maximum, in. (mm) 1 Under 2 (50) 0.020 (0.51) 2 2 through 3(50-75) 0.030 (0.76) 3 Over 3 through 4 (75-100) 0.040 (1.02) 4 Greater than 4 (100) 0.070 (1.78) Note: Material thickness is thickness on which the IQI is based. The acceptable sensitivity for various thickness components and Number of IQI and placement location of the IQI shall be in accordance with applicable standard or code. September 2017, R00 Page 30 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 3.8 Processing Films are processed in accordance with the conditions recommended by the film and chemical manufacturer to obtain the selected film system class. Particular attention shall be paid to temperature, developing time and washing time. Residue Thiosulfate on radiographs shall be checked using Kodak Hypo Test Kit or other equivalent and approved test method. The amount of thiosulfate ion residue shall be less than 0.05 gm/m2. The radiographs should be free from imperfections due to processing or other causes which would interfere with interpretation. 3.9 Film Viewing Condition The radiographs should be examined in a darkened room (or other equivalent, approved specification) on a viewing screen with an adjustable luminance (or other equivalent, approved specification). The viewing screen should be masked from the area of interest. September 2017, R00 Page 31 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification Appendix 2. 10012-STD-6-INT-003-R00 Various Radiographic Technique These various radiographic techniques as shown in Appendix 2 shall be performed by complying with ASME V, Article 2 Mandatory Appendices. List of radiographic technique was presented as below; In-Motion Radiography In-motion radiography is a technique of radiography where the object being radiographed and/or the source of radiation is in motion during the exposure. In-motion radiography may be performed on weldments when the following modified provisions to those in ASME V, Article 2, are satisfied. Real-Time Radiographic Examination Real-time radioscopy provides immediate response imaging with the capability to follow motion of the inspected part. This includes radioscopy where the motion of the test object must be limited (commonly referred to as near real-time radioscopy). Realtime radioscopy may be performed on materials including castings and weldments when the modified provisions to ASME V, Article 2, as indicated herein are satisfied. ASTM E 1255 shall be used in conjunction with this Appendix as indicated by specific references in appropriate paragraphs. ASTM E 1416 provides additional information that may be used for radioscopic examination of welds. Digital Image Acquisition, Display, and Storage for Radiography and Radioscopy Digital image acquisition, display, and storage can be applied to radiography and radioscopy. Once the analog image is converted to digital format, the data can be displayed, processed, quantified, stored, retrieved, and converted back to the original analog format, for example, film or video presentation. Digital imaging of all radiographic and radioscopic examination test results shall be performed in accordance with the modified provisions to ASME V, Article 2, as indicated herein. September 2017, R00 Page 32 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version Radiographic Examination Specification 10012-STD-6-INT-003-R00 LAST PAGE – INTENTIONALLY BLANK September 2017, R00 Page 33 of 33 UNCONTROLLED when printed, visit PTTEP Intranet for latest version