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Ministry of Defence

Defence Standard 02-729 (NES 729)

Issue 1 Publication Date 01 April 2000

Incorporating NES 729 Category 2

Issue 2 Publication Date November 1991

Requirements For Non-Destructive

Examination Methods

Part 1Radiographic

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AMENDMENT RECORD

Amd No Date Text Affected Signature and Date

REVISION NOTE

This standard is raised to Issue 1 to update its content.

HISTORICAL RECORD

This standard supersedes the following:

Naval Engineering Standard (NES) 729 Part 1 Issue 2 dated November 1991.

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Ministry of Defence

Naval Engineering Standard

NES 729 Part 1 Issue 2 (Reformatted) November 1991

REQUIREMENTS FOR NON-DESTRUCTIVE

EXAMINATION METHODS

PART 1

RADIOGRAPHIC

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This NES Supersedes

NES 729 PART 1 ISSUE 1

Record of Amendments

AMDT INSERTED BY DATE

1

2

3

4

5

6

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8

9

10

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i

NAVAL ENGINEERING STANDARD 729

REQUIREMENTS FOR NON-DESTRUCTIVE EXAMINATION METHODS

PART 1

ISSUE 2 (REFORMATTED)

RADIOGRAPHIC

The issue and use of this Standard

is authorized for use in MOD contracts

by MOD(PE) Sea Systems and

the Naval Support Command

ECROWN COPYRIGHT

Published by:

Director of Naval Architecture

Procurement Executive, Ministry of Defence

Sea Systems, Foxhill, Bath BA1 5AB

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NES 729Part 1

Issue 2 (Reformatted)

iii

SCOPE

1. This part of NES 729 covers the minimum requirements for the radiographic examinationmethod used to detect internal discontinuities in welded joints and metallic materialsincluding casting, pipes and fabrication.

2. The NES applies to all items for which specifications, standards, drawings, or refit/repairinstructions require radiographic examination, by x-ray or gamma-ray techniques.

3. The NES also covers the Quality Assessment of Examining Authorities who performradiographic examination.

4. The extent to which radiographic examination is required is not included herein but will befound in the relevant Contract Documents.

5. It does not contain acceptance criteria for defects.

6. The NES does not apply to the examination of nuclear plant and machinery.

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NES 729Part 1Issue 2 (Reformatted)

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NES 729Part 1


v

FOREWORD

Sponsorship

1. This Naval Engineering Standard (NES) is sponsored by the Procurement Executive, Ministry

of Defence, Director Naval Architecture (Submarines) (DNA(SM)), Section NA 133.

2. It is to be applied as required by any Procurement Executive, Ministry of Defence contract forthe non-destructive examination of metals and is applicable to Surface Ships and Submarines.

3. This NES comprises:

Requirements for Non-destructive Examination Methods thus

Part 1 Radiographic

Part 2 Magnetic Particle

Part 3 Eddy Current

Part 4 Liquid Penetrant

Part 5 Ultrasonic

4. If it is found to be technically unsuitable for any particular requirement the Sponsor is to beinformed in writing of the circumstances with a copy to Director Naval Architecture SurfaceShips (DNA(SS)), NA 145.

5. Any user of this NES either within MOD or in industry may propose an amendment to it.Proposals for amendments which are:

a. not directly applicable to a particular contract are to be made to the Sponsor of the NES;

b. directly applicable to a particular contract are to be dealt with using existingdepartmental procedures or as specified in the contract.

6. No alteration is to be made to this NES except by the issue of an authorized amendment.

7. Unless otherwise stated, reference in this NES to approval, approved, authorized or similar

terms, means by the Procurement Executive, Ministry of Defence.

8. Any significant amendments that may be made to this NES at a later date will be indicatedby a vertical sideline. Deletions will be indicated by 000 appearing at the end of the lineinterval.

9. This NES has been reissued to reflect the changes in nomenclature and technicalrequirements in line with current policy.

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Conditions of Release

General

10. This Naval Engineering Standard (NES) has been prepared for the use of the Crown and ofits contractors in the execution of contracts for the Crown. The Crown hereby excludes all

liability (other than liability for death or personal injury) whatsoever and howsoever arising(including but without limitation, negligence on the part of the Crown, its servants or agents)for any loss or damage however caused where the NES is used for any other purpose.

11. This document is Crown Copyright and the information herein may be subject to Crown orthird party rights. It is not to be released, reproduced or published without written permissionof the MOD.

12. The Crown reserves the right to amend or modify the contents of this NES without consultingor informing any holder.

MOD Tender or Contract Process

13. This NES is the property of the Crown and unless otherwise authorized in writing by the MODmust be returned on completion of the contract, or submission of the tender, in connectionwith which it is issued.

14. When this NES is used in connection with a MOD tender or contract, the user is to ensure thathe is in possession of the appropriate version of each document, including related documents,relevant to each particular tender or contract. Enquiries in this connection may be made ofthe local MOD(PE) Quality Assurance Representative or the Authority named in the tenderor contract.

15. When NES are incorporated into MOD contracts, users are responsible for their correctapplication and for complying with contracts and any other statutory requirements.

Compliance with an NES does not of itself confer immunity from legal obligations.

Related Documents

16. In the tender and procurement processes the related documents listed in each section andAnnex A can be obtained as follows:

a. British Standards British Standards Institution,389 Chiswick High Road,London W4 4AL

b. Defence Standards Directorate of Standardization and Safety Policy,Stan 1, Kentigern House, 65 Brown Street,Glasgow G2 8EX

c. Naval Engineering Standards CSE3a, CSE Llangennech, Llanelli,Dyfed SA14 8YP

d. Other documents Tender or Contract Sponsor to advise.

Note: Tender or Contract Sponsor can advise in cases of difficulty.

17. All applications to Ministry Establishments for related documents are to quote the relevantMOD Invitation to Tender or Contract Number and date, together with the sponsoringDirectorate and the Tender or Contract Sponsor.

18. Prime Contractors are responsible for supplying their subcontractors with relevantdocumentation, including specifications, standards and drawings.

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Health and Safety

Warning

19. This NES may call for the use of processes, substances and/or procedures that may be injuriousto health if adequate precautions are not taken. It refers only to technical suitability and in

no way absolves either the supplier or the user from statutory obligations relating to healthand safety at any stage of manufacture or use. Where attention is drawn to hazards, thosequoted may not necessarily be exhaustive.

Safety

20. Radiographic exposures are to be made under protected conditions in accordance withstatutory requirements.

21. All equipment involving the use of main electrical supply is to conform to the relevantstatutory requirements and safety regulations.

22. All examinations referred to in this NES are to be carried out with due regard to applicablestatutory requirements, safety regulations and Codes of Practice.

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ix

CONTENTS

Page No

TITLE PAGE i. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SCOPE iii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FOREWORD v. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sponsorship v. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Conditions of Release vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MOD Tender or Contract Process vi. . . . . . . . . . . . . . . . . . . . . . . . . .

Related Documents vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Health and Safety vii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Warning vii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Safety vii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CONTENTS ix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 1. ACCEPTANCE STANDARDS 1.1. . . . . . . . . . . . . . . . .

SECTION 2. INSPECTION 2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 3. APPROVAL REQUIREMENTS 3.1. . . . . . . . . . . . . . . .

3.1 Personnel Qualification 3.1. . . . . . . . . . . . . . . . . . . . . . .

3.2 Radiographic Procedures 3.1. . . . . . . . . . . . . . . . . . . . . .

TABLE 3.1 MATERIAL GROUPING FORRADIOGRAPHIC PROCEDURES 3.1. . . . . . . . . . . . .

3.3 Radiographic Equipment Qualification 3.3. . . . . . . . . .

FIGURE 3.1 TYPICAL STANDARDRADIOGRAPHIC REPORT 3.4. . . . . . . . . . . . . . . . . . .

FIGURE 3.2 MINIMUM FOCUS ORSOURCE-TO-FILM DISTANCE v EFFECTIVESOURCE SIZE 3.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FIGURE 3.3 RECOMMENDED X-RAYVOLTAGES AND RADIO-ISOTOPE SOURCESFOR USE WITH VARIOUS STEELS ANDSIMILAR ALLOYS 2% SENSITIVITY LEVEL 3.6. .

FIGURE 3.4 RECOMMENDED X-RAY

VOLTAGES AND RADIO-ISOTOPE SOURCESFOR USE WITH COPPER BASE ANDSIMILAR ALLOYS 2% SENSITIVITY LEVEL 3.7. .

SECTION 4. SURFACE PREPARATION 4.1. . . . . . . . . . . . . . . . . . .

SECTION 5. RADIATION SOURCES 5.1. . . . . . . . . . . . . . . . . . . . . .

5.1 Thickness Limitations 5.1. . . . . . . . . . . . . . . . . . . . . . . .

5.2 Source Dimensions 5.1. . . . . . . . . . . . . . . . . . . . . . . . . . .

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SECTION 6. PRODUCTION RADIOGRAPHY 6.1. . . . . . . . . . . . . .

6.1 Direction of Radiation 6.1. . . . . . . . . . . . . . . . . . . . . . . .

6.2 Image Quality Level 6.1. . . . . . . . . . . . . . . . . . . . . . . . . .

6.3 Screens and Filters 6.1. . . . . . . . . . . . . . . . . . . . . . . . . . .

6.4 Film 6.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.5 Film Quality 6.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .FIGURE 6.1 SELECTION OF IQI WIRENUMBER FOR PERCENTAGE SENSITIVITY:WIRE TYPE BS 3971 6.2. . . . . . . . . . . . . . . . . . . . . . . . .

FIGURE 6.2 SELECTION OF IQI WIRE NUMBERFOR PERCENTAGE SENSITIVITY: WIRETYPEDIN 54109 6.3. . . . . . . . . . . . . . . . . . . . . . . . . . .

TABLE 6.1 SCREENS AND FILTERS 6.4. . . . . . . . . .

6.6 Cassettes 6.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.7 Film Density 6.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.8 Multiple-Film Technique 6.5. . . . . . . . . . . . . . . . . . . . . .

6.9 Filmless Techniques 6.5. . . . . . . . . . . . . . . . . . . . . . . . . .6.10 Focus/Source to Film Distance 6.5. . . . . . . . . . . . . . . . .

TABLE 6.2 SOURCE-TO-FILM DISTANCEFOR THE RADIOGRAPHY OF PIPE WELDSUSING GAMMA RAYS AND DOUBLE-WALLDOUBLE-IMAGE TECHNIQUE 6.5. . . . . . . . . . . . . . .

6.11 Diagnostic Film Length 6.6. . . . . . . . . . . . . . . . . . . . . . .

6.12 Radiograph Location Markers 6.7. . . . . . . . . . . . . . . . .

6.13 Film Identification 6.7. . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 7. STORAGE OF RADIOGRAPHS AND

RADIOGRAPHIC RECORDS 7.1. . . . . . . . . . . . . . . . .

SECTION 8. DARKROOM FACILITIES 8.1. . . . . . . . . . . . . . . . . . .

SECTION 9. FILM VIEWING FACILITIES 9.1. . . . . . . . . . . . . . . . .

SECTION 10. INTERPRETATION OF RADIOGRAPHS 10.1. . . . . . .

FIGURE 10.1 METHOD OF MARKING WELDSFOR RADIOGRAPHY 10.2. . . . . . . . . . . . . . . . . . . . . . .

SECTION 11. IMAGE QUALITY INDICATORS 11.1. . . . . . . . . . . . . .

11.1 General 11.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11.2 IQI Materials 11.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11.3 Wire Type IQI DIN 54109 11.1. . . . . . . . . . . . . . . . . . . . .

11.4 Wire Type IQI BS 3971 11.1. . . . . . . . . . . . . . . . . . . . . . .

11.5 IQI Identification 11.2. . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 12. IQI LOCATION 12.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TABLE 12.1 IQI LOCATION FORCIRCUMFERENTIAL WELDS 12.2. . . . . . . . . . . . . . . .

SECTION 13. RADIOGRAPHY OF PIPE WELDS 13.1. . . . . . . . . . . .

13.1 Single-Wall Technique 13.1. . . . . . . . . . . . . . . . . . . . . . . .

13.2 Double-Wall Single-Image Technique 13.1. . . . . . . . . . .

13.3 Double-Wall Double-Image Technique 13.1. . . . . . . . . . .

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SECTION 14. WELDS WITH OVERLAY CLADDING 14.1. . . . . . . .

SECTION 15. SIMULTANEOUS EXPOSURES 15.1. . . . . . . . . . . . . . .

SECTION 16. RADIOGRAPHY OF SMALL PARTS 16.1. . . . . . . . . .

SECTION 17. RADIOGRAPHY OF REPAIR WELDS 17.1. . . . . . . . .

SECTION 18. RADIOGRAPHY OF CASTINGS 18.1. . . . . . . . . . . . . .

18.1 Techniques 18.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18.2 Technique Shot Films 18.1. . . . . . . . . . . . . . . . . . . . . . . . .

ANNEX A. RELATED DOCUMENTS A.1. . . . . . . . . . . . . . . . . . . .

ANNEX B. DEFINITIONS AND ABBREVIATIONS B.1. . . . . . . .

ANNEX C. PROCUREMENT CHECK LIST C.1. . . . . . . . . . . . . . .

ALPHABETICAL INDEX

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1.1

1. ACCEPTANCE STANDARDS

a. The standards for acceptance of defect indications detected by radiographicexamination are to be specified in the Contract; where not specified therein,DG Ships/G/10000B or NES 745 Parts 1 and 2 is to apply as appropriate.

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1.2

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2.1

2. INSPECTION

a. It is not the intent of this part of NES 729 to exclude proven radiographicinspection procedures which can be demonstrated to meet the qualityrequirements. However prior MOD(PE) approval is to be obtained before suchprocedures are used.

b. Unless otherwise specified in the Contract, acceptance radiography is to beperformed after final heat treatment.

c. The material thickness at final acceptance radiography is not to exceed thefinished thickness of the section under examination by more than 20% or 6mmwhichever is the greater.

d. The extent of radiographic examination is to be included in the Contractdetailed in SCOPE 4. and is to include the number of areas and items to beradiographed, the stage in fabrication when this is to be performed (if differentfrom that stated in Clause 2.b.), the quality level of inspection and the

acceptance standard to be applied.

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2.2

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3.1

3. APPROVAL REQUIREMENTS

3.1 Personnel Qualification

a. The Examining Authority is to ensure that all personnel associated withradiographic examination have been trained and certificated to the levelsappropriate to their responsibilities. This certification is to relate to a Nationalor International accreditation scheme, eg Personnel Certification inNon-Destructive Testing (PCN).

b. A register of approved personnel shall be kept by the Examining Authority.

3.2 Radiographic Procedures

a. MOD(PE) approval of radiographic procedures is to be obtained prior toradiographic examination of production items. Radiographic and filmprocessing procedures are to form a part of the standard procedure approval.

b. Separate procedures are to cover the requirements for the radiographicexamination of structural welding, castings, forgings and pipe welds.

c. The relevant contract documents are to define the extent of the radiographicexamination and the appropriate acceptance standards to be applied.

d. Inspections to radiographic procedures are to be carried out by approvedpersonnel qualified in accordance with Clause 3.1a.

e. Materials are to be grouped in accordance with TABLE 3.1. For materialshaving substantially different radiographic absorption characteristics fromthose in Groups 1, 2 and 3 (see TABLE 3.1) procedure approval is to be relatedto reference samples simulating production requirements.

GROUP NO TYPICAL METALS/ALLOYS

1 Carbon: low alloy, high alloy steels, including stainless steels:nickel chromium iron alloys; nickel aluminium bronze

2 Copper; copper nickel alloys; gun metal; nickel copper alloys

3 Light metals; eg aluminium, magnesium, titanium alloys

TABLE 3.1 MATERIAL GROUPING FOR RADIOGRAPHIC PROCEDURES

f. Radiographic procedures are to reference all relevant documents, specificationsand acceptance standards. The procedures are to be recorded and maintainedby the Examining Authority for audit purposes.

g. Radiographic procedures are to cover all pre-requisites and technical

requirements associated with the relevant application and are to containspecific guidance information including the following:

(1) type of production item, eg welds, castings etc;

(2) material group;

(3) material;

(4) method of marking radiographic and production items;

(5) x-ray equipment information:

(a) focal spot size,

(b) tube voltage (expressed as kV),

(c) tube current (expressed as mA);

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3.2

(6) isotope information:

(a) type of isotope;

(b) source dimensions;

(7) type of film cassettes and type of film;(8) type and thickness of intensifying screens;

(9) type of IQI, location and required film sensitivity;

(10) object to film distance FSD or FFD;

(11) radiation direction and film disposition;

(12) film image density;

(13) film processing technique;

(14) film viewing facilities.

A suitable format for radiographic report is shown in FIGURE 3.1.

h. The radiographic procedure is to be reapproved in accordance withClauses 3.2a.!3.2i. when:

(1) the MOD(PE) has reason to believe that the Examining Authority cannotmeet the required radiographic quality levels in production radiographyusing the previously approved procedure;

(2) an isotope of larger physical size, or X-ray tube of larger focal spot size,

than that used in the approved procedure is to be used, unless thesource-to-film distance (SFD) or focus-to-film distance (FFD) ismaintained within the limits of FIGURE 3.2;

(3) there is a change in the type of isotope source used;

(4) there is a change in the type of X-ray equipment used;

(5) the X-ray equipment voltage is greater than that used during initialqualification and greater than the maximum value permissible inFIGURE 3.3 and FIGURE 3.4 for the material thickness underexamination;

(6) there is a change in the type of film;

(7) there is a reduction of the SFD or FFD below the minimum shown inFIGURE 3.2 unless inaccessibility prevents compliance (in the latter case,the Examining Authority is to verify that the greatest possible SFD/FFDis used and that the radiographic record shows that accessibility limits theSFD or FFD);

(8) there is an increase in the thickness of intensifying screens beyond thethickness qualified and beyond the maximum permitted by TABLE 6.1;

(9) there is a change in the type of intensifying screen material used.

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3.3

i. All radiographic examinations are to be recorded in a radiographic report inwhich the following information is to be recorded:

(1) relevant radiographic procedure;

(2) name(s) of qualified operators;

(3) description of the component, location, material and thickness;

(4) contractual details;

(5) radiographic technical details;

(6) film coverage;

(7) date, place and time of examination.

NOTE: A specimen radiographic report showing the minimum information to berecorded is at FIGURE 3.1.

3.3 Radiographic EquipmentQualification

a. Radiographic test equipment is to be capable of consistently producingradiographs to the required quality in accordance with this NES and anapproved written procedure.

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3.4

Procedure No . . . . . . . . . . . . . . . . . Issue No . . . . . . . . . . . . . . . . . . Date . . . . . . . . . .

Company . . . . . . . . . . . . . . . . . . . Procedure drafted by . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . Approved by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . .

Radiographed by . . . . . . . . . . . . . Radiographic Report No . . . . . . . . . . . . . . . . . . . . . . . .

COMPONENT DESCRIPTION

Title . . . . . . . . . . . . . . . . . . . . . . . MOD Contract Order No . . . . . . . . . . . . . . . . . . . . . . .

Drg No . . . . . . . . . . . . . . . . . . . . . Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Material Spec No . . . . . . . . . . . . . Casting/Forging/Weld/Other . . . . . . . . . . . . . . . . . . . .

Location . . . . . . . . . . . . . . . . . . . . Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TECHNIQUE DETAILS

1. Radiation Source

X-ray . . . . . . . . . . . . . . . . . Gamma-ray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Kilovoltage . . . . . . . . . . . . Isotope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Anode current . . . . . . . . . mA/Source strength . . . . . . . . . . . . . . . . . . . . . . . . . .

Effective source-size . . . . mm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mm

Exposure time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Equipment manufacturer . . . . . . . . . . . . . . . . . . . Model or type . . . . . . . . . . . . . . . .

2. Geometry

Source film distance . . . . . . . . . . . . . . . mm

Principal beam angulation . . . . . . . . . . . . . . . . . to normal

Area examinedsize . . . . . . . . . . . . . . mm . . . . . . . . . . mm

IQI-Type . . . . . . . . . . . . . . . . . . . Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Required sensitivity . . . . . . . . %

Sensitivity achieved . . . . . . . . . %

3. Photographic Details

Film: Make . . . . . . . . . . . . . . . . . Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Size . . . . . . . . . . . . . . . . . . . . . . . mm . . . . . . . . . . . . . . . . . . . mm

ScreensType . . . . . . . . . . . . . . Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Backscatter control . . . . . . . . . . . Block medium . . . . . . . . . . . . . . . . . . . . . . . . . . .

Processing: Type . . . . . . . . . . . . . Time . . . . . . . . . . . . . . . . Temp . . . . . . . . . . .

Density required . . . . . . . . . . . . .

Density achieved . . . . . . . . . . . . .

4. Coverage

No of films . . . . . . . . . . . . . . . . .

Marking system etc, shown separately in attached sketch . . . . . . . . . . . . . . . . . . . . .

5. Acceptance Standard Specification . . . . . . . . . . . . . .

6. Other information

7. Results of examination

Shooting sketches to be added as necessary

FIGURE 3.1 TYPICAL STANDARD RADIOGRAPHIC REPORT

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3.5

FIGURE 3.2 MINIMUM FOCUS OR SOURCE-TO-FILM DISTANCE v EFFECTIVE

SOURCE SIZE

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3.6

FIGURE 3.3 RECOMMENDED X-RAY VOLTAGES AND RADIO-ISOTOPE SOURCES FOR

USE WITH VARIOUS STEELS AND SIMILAR ALLOYS.2% SENSITIVITY LEVEL

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3.7

FIGURE 3.4 RECOMMENDED X-RAY VOLTAGES AND RADIO-ISOTOPE SOURCES FOR

USE WITH COPPER BASE AND SIMILAR ALLOYS.2% SENSITIVITY LEVEL

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3.8

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4.1

4. SURFACE PREPARATION

a. Accessible surfaces of castings and welds to be radiographed are to be dressedas necessary to prevent the occurrence of indications on the radiographsresulting from weld beads, ripples, slag, scale and other surface irregularitieswhich could interfere with the interpretation of the radiographs. Such dressing

is to be in accordance with limitations in NES 745 Parts 1 and 2 for castingsurfaces and DGS/G/10000B for weld surfaces.

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4.2

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5.1

5. RADIATION SOURCES

a. Gamma-R ay I sotopes

The following gamma-ray isotopes may be used.

Thulium (Tm) 170

Iridium (Ir) 192

Caesium (Cs) 137

Cobalt (Co) 60

Ytterbium (Yb) 169

The use of any other gamma radiation sources requires specific MOD(PE)approval.

b. X-R ay Sour ces

X-ray sources may be used providing the values of the kilovoltage againstmaterial type and thickness complies with those recommended in FIGURE 3.3and FIGURE 3.4.

5.1 Thickness Limitations

a. Guidance regarding X-ray voltage and gamma-ray sources to be used withvarious specimen thicknesses for optimum radiographic results (given inFIGURE 3.3 and FIGURE 3.4) is not to be taken to imply that on thesethicknesses the flaw sensitivity with gamma-rays is equivalent to that with

X-rays. In general, any gamma-ray technique will be less sensitive than an X-raytechnique on material thicknesses of less than 50mm. On material thickness50mm and greater the difference in sensitivity is less marked and is dependentupon the actual gamma-ray technique used.

5.2 Source Dimensions

a. A cylindrical isotope source whose length is greater than its diameter will havea greater effective radiation sources dimension when oriented coaxially in thecentre of a pipe for a panoramic exposure than when the axis of the source ispositioned at right angles to the pipe. For a focal spot projected asa square imagethe diagonal of the square is to be used for calculation.

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5.2

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6.1

6. PRODUCTION RADIOGRAPHY

6.1 Direction of Radiation

a. Whenever appropriate, the radiation beam is to be directed perpendicularly tothe external surface and/or axis of the section under examination. Beam angling

is, however, permissible where required to determine the type, location and/ordimensions of a defect.

6.2 Image Quality Level

a. Radiography is to be performed with a technique which will distinguish theacceptable Image Quality Indicator (IQI), (see Section 10.). Radiography qualitylevel is to be determined by using one or more of the IQIs referred to inFIGURE 6.1 and FIGURE 6.2. Unless otherwise specified, 2% IQI sensitivity isto be used as a standard for evaluating radiography quality for materials up toand including 50mm thick, and 1X above this thickness.

NOTE: For a particular thickness the IQI sensitivity provides a means bywhich the quality of radiographic techniques may be compared.

6.3 Screens and Filters

a. Radiographic procedures which use either a gamma source or an X-ray sourceof 120kV or greater are to include front and back screens in accordance withTABLE 6.1 and the notes applicable. Screen surfaces are to be free of blemisheswhich may produce spurious indications in the resultant radiograph.

6.4 Film

a. Whenever gamma radiography is used radiographs are to be made on fine grain

or ultra-fine grain, high contrast, safety base film.

6.5 FilmQuality

a. Radiographs presented for interpretation are to be free from blemishes or filmdefects which might mask, or be confused with, defects in the material beingexamined. If doubt exists concerning the true nature of an indication on thefilm, the radiograph is to be rejected. Typical blemishes are as follows:

(1) fogging caused by light leaks in the processing room or cassettes or bydefective safelights or marks caused by improper processing or by use ofold film;

(2) mechanical processing defects such as streaking, air bubbles or watermarks or chemical stains;

(3) pressure or lead marks, scratches, gouges, finger marks, crimp marks orstatic electricity marks;

(4) loss of detail caused by poor film-to-screen contact in localized areas.

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6.2

FIGURE 6.1 SELECTION OF IQI WIRE NUMBER FOR PERCENTAGE SENSITIVITY:

WIRE TYPE BS 3971

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6.3

FIGURE 6.2 SELECTION OF IQI WIRE NUMBER FOR PERCENTAGE SENSITIVITY: WIRE

TYPEDIN 54109

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6.4

SCREEN SCREEN THICKNESS

MATERIAL FRONT (MM) BACK (MM)

X-rays below 120kV Lead none 0.1 minimum

X-rays 120 to 250kV Lead 0.025 to 0.125 0.1 minimum

X-rays 250 to 400kV Lead 0.05 to 0.16 0.1 minimum

X-rays 1 to 8 MeV Lead or

Copper1 to 1.6 1 to 1.6

X-rays above 8 MeV Lead,Tantalum or

Tungsten

1 to 1.6 None

Gamma-rays Ir 192 and Cs 137 Lead 0.05 to 0.16 0.15 minimum

Gamma-rays Co 60 Lead, Steel or

Copper0.5 to 2.0 0.25 to 1.0

Gamma-rays Yb 169 and

Tm 170

Lead 0.05 to 0.16 0.1 minimum

Gamma-rays Yb 169 Lead 0.02 0.02

TABLE 6.1 SCREENS AND FILTERS

NOTES 1. I ntensif ying Scr eens.Intimate contact between the screens andthe film is to be maintained during exposure. The use of fluorescentscreens requires specific approval of the MOD(PE).

2. Back F il ters.Lead filters are to be used behind the film holder toprevent scattered radiation from the floor, walls, air or surroundingobjects from fogging the film. Each film holder is to have a lead letter

B, a minimum of 12mm high and a minimum of 1.5mm thick,fastened to the back of the film holder within the area of film to beread. An image of the lead letter, appearing on the film, indicatesthat additional back filter thickness is required and is to be cause forrejection of the radiograph.

3. For Cobalt 60 the use of copper or steel screens produces the bestflawsensitivity but a longer exposure time is required than with leadscreens (in the order of 2 to 1).

4. Below 5mm material thickness, image quality is improved by theomission of lead screens.

6.6 Cassettes

a. Cassettes may be rigid or flexible types with the exception of Ytterbium 169technique. They are to be light tight and able to maintain close film-to-screencontact.

b. For Ytterbium 169 radio-isotope sources only plastic cassettes/ film holders areto be used. Vacuum loading techniques are preferred to ensure positive screento film contact.

6.7 Film Density

a. The optical density of individual films is normally to be between 2.0 and 3.0 inthe area being examined. Densities in excess of 3.0 may be accepted for viewingonly if adequate high intensity viewing facilities are available.

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6.5

6.8 Multiple-Film Technique

a. When the thickness of the part varies considerably in the area underexamination, two or more films, of either equal or different speeds as employedduring procedure qualification, may be exposed simultaneously in the same filmholder and the resultant radiographs submitted for interpretation as single

films. This technique is to employ the use of a centre screen placed between thefilms to be exposed in addition to the required front and back screens.

6.9 Filmless Techniques

a. The use of filmless techniques is to be limited to in process inspection and isto be subject to the prior approval of the MOD(PE).

6.10 Focus/Source to Film Distance

a. The minimum focus or source-to-film distance (FFD or SFD) is to be inaccordance with FIGURE 3.2 which is applicable to all techniques exceptdouble-wall double-image radiography of pipe welds using gamma-rays to

which TABLE 6.2 applies.

b. The geometric image unsharpness (Ug) assumes greater importance as thedistance between defect and film increases and therefore this distance is to bekept at a minimum for optimum assessment of defect. Further exposures mayalso be required for this purpose. The use of longer SFD may improve definition.The Ug value is not to exceed the inherent unsharpness of the film-screencombination for the type of radiation used, as defined in BS 2600 Part 1.

c. The FFD or SFD is to be compatible with the minimum sharpness valueobtainable and any practical limitations that prevent the latter being achievedare to be indicated in the radiographic procedure as submitted for approval.

OUTSIDE

SOURCE-TO-FILM DISTANCE AS A MULTIPLE OF THE OUTSIDEDIAMETER OF PIPE

DIAM OF CYLINDRICAL SOURCE SIZE AND ORIENTATION USED

MM 0.5mm 0.5mm 1mm 1mm 1.3mm 1.3mm 2mm 2mm

End on Side on End on Side on End on Side on End on Side on

10 3 to 4 3.8!5.5 5!7 6.6!9 6.2!8.6 8.2!11.5 9.13 12.2!17

20 3!4 3.8!5.5 5!7 6.6!9 6.2!8.6 8.2!11.5 9!12.5 12.2!17.5

30 3!4 3.8!5.3 5!7 6.6!9 6.2!8.6 8.2!11.6 9!12.5 12.2!17.5

40 3!4 3.8!5.3 5!6.8 6.6!9 6.2!8.6 8.2!11.6 9!12.5 12.2!17.5

50 3!

4 3.8!

5.2 5!

6.8 6.6!

9 6.2!

8.6 8.2!

11.7 9!

12.5 12.2!

1760 3!4 3.8!5.2 5!6.8 6.6!9 6.2!8.6 8.2!11.7 9!12 12.2!17

70 3!4 3.8!5.1 5!6.7 6.6!9 6.2!8.6 8.2!11.7 9!12 12.2!15.5

80 3!4 3.8!5.1 5!6.7 6.6!9 6.2!8.6 8.2!11.7 9!12 12.2!15

90 3!4 3.8!5.1 5!6.7 6.6!9 6.2!8.6 8.2!11.7 9!11 12.2!15

Cut-off point for double-wall double-image technique

NOTE The figures in the above table are based on geometric unsharpness values notexceeding 0.25mm.

Wherever possible the longer source-to-film distance is used.

TABLE 6.2 SOURCE-TO-FILM DISTANCE FOR THE RADIOGRAPHY OF PIPE

WELDS USING GAMMA RAYS AND DOUBLE-WALL DOUBLE-IMAGE TECHNIQUE

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6.6

d. The following factors are also to be taken into account in SFD calculations:

(1) the film is to be located as close to the item being examined as possible;

(2) where a gap unavoidably exists between the film and the item themaximum gap width is to be added to the specimen thickness for thecalculation of the SFD;

(3) all calculations are to be based on the maximum effective sourcedimensions. For a focal spot or source projected as a rectangle the effectivedimensions is the length of the diagonal of the rectangle, ie effective

dimension = X2 !Y2" mm where X and Y are lengths of rectangle

sides;

(4) the effective dimension for a focal spot projection consisting of dividedimages is the diameter of the smallest circle circumscribing both images;

(5) the effective size of the focal spot for each X-ray tube is to be establishedusing the pinhole method and checked at least once per year throughoutits working life;

(6) for double-wall single-image radiography the material thickness to beused for the calculation of the minimum SFD is the thickness of the wallto be examined plus the thickness of the backing strip if featured;

(7) for double-wall double-image radiography the material thickness to beused for the calculation of the minimum SFD is the maximum dimensionsbetween the specimen surface and the film, ie the outside diameter of thepipe irrespective of the pipe wall thickness;

(8) for steel greater than 50mm in thickness reference is to be made toBS 2600 (Part 2).

6.11 Diagnostic Film Length

a. The diagnostic film length of the weld or part under examination is to be suchthat the thickness of the material at the extremities of the exposed areameasured in the direction of the incident beam at that point, does not exceedthe actual thickness (T) at that point by more than the relevant value statedbelow:

(1) X-ray techniques with ultra-fine grain and fine grain high contrastdirect-type film

max incident thickness = T ! 6%

(2) X-ray techniques with medium speed, direct-type film


(3) Gamma-ray techniques with ultra-fine grain and fine grain high contrastdirect-type film


b. The diagnostic film length for pipe welds, pipes and castings of small radius andwith thickness variation will generally determine the number of exposuresrequired for full coverage of the weld examined.

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6.7

6.12 Radiograph Location Markers

a. The images of the location markers used to correlate the part with the film areto confirm complete coverage without interfering with the interpretation.Marker positions are to be marked on the part and maintained on the partthroughout radiography. When radiographing a weld, the edge of the marker

image is to be approximately 3mm from the edge of the weld wherever possible.

6.13 Film Identification

a. A system of positive identification of the film and the IQI type used is to beprovided.

(1) The following information is to appear on each radiograph:

(a) identification of the organization making the radiograph;

(b) identification code letters related to Clause 6.13a.(1) where spacepermits;

(c) a unique identification number;

(d) a suffix letter R to denote a repair radiograph where applicable,followed by the number of the repair, eg R2, R3 etc.

(2) The above information is also to appear in the records that accompanyeach radiograph together with:

(a) identification of the item, part, component or system, and whereapplicable, the weld joint;

(b) details of the radiographic technique used and date of exposure.

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6.8

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7.1

7. STORAGE OF RADIOGRAPHS AND RADIOGRAPHIC RECORDS

a. Radiographs and radiographic records are to be retained for seven years fromcompletion of a fixed term contract. Where work is performed under continuingcontract, or on other than a contractual basis, these are to be retained for seven

years from the date on which the work was performed. Technique details,

including radiographic inspection location sketches, evaluation and dispositionsheets are to be included in the records retained. At the end of the seven-yearperiod, the Organization is to ask MOD(PE) whether the records are to bedestroyed, forwarded to MOD(PE) or retained by the Organization for a furtherperiod.

b. When radiography is performed by a subcontractor, he is to provide the PrimeContractor with all radiographs and radiographic records required for retentionin accordance with Clause 7.a.

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7.2

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8.1

8. DARKROOM FACILITIES

a. Darkroom facilities, including equipment and materials, are to be capable ofproducing uniform, blemish-free radiographs and of controlling film processingprocedures in accordance with the recommendations of the manufacturers.Records are to be maintained for the purpose of assuring control of the life and

quality of the photographic solutions and the effectiveness of the safelightconditions.

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8.2

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9.1

9. FILM VIEWING FACILITIES

a. Radiographs are to be examined by diffused light in a darkened room or cubiclethat is suitable for this purpose.

b. Viewing facilities and background lighting are to minimize reflection on the

radiographs.

c. Equipment used for radiographic interpretation is to include the followingminimum requirements:

(1) a controllable light source of sufficient maximum intensity to allow theselection of optimum intensities for viewing the ranges of film densitiesspecified in Clause 6.7a. The light enclosure is to be so designed as toprovide a uniform level of illumination over the entire viewing surface.The required light intensity for viewing film densities over 3.0 may beprovided by the use of a separate high intensity viewing port. Filmdamaged owing to exposure to heat is to be rejected and repeat

radiography carried out;

(2) the provision of a suitable fan or blower or other cooling device, andlimitation of the time of contact of the film with the viewing port in orderto avoid film damage caused by excess heat at the viewing port of highintensity viewers;

(3) masking facilities to suit the sizes of radiographs to be viewed;

(4) densitometers to ensure compliance with the film density requirementsof Clause 6.7a.

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9.2

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10.1

10. INTERPRETATION OF RADIOGRAPHS

a. To assist in the proper interpretation of radiographs, a sketch or drawing andwritten technique or equivalent record, as per Clause 3.2i., is to be prepared toshow the arrangement used to make each radiograph. This information is toaccompany each relevant radiograph, or group of radiographs. Reference to a

standard arrangement is to be acceptable if details of the standardarrangements are made available. The required information is to include, whereapplicable:

(1) number of films;

(2) location of each film on the radiographed item. The film position is to berecorded relative to the film centre marker and some fixed datum;

(3) orientation of location markers. The preferred arrangement forweldments is shown in FIGURE 10.1;

(4) location of radiation source, including source-to-film distance and angleof beam;

(5) type of weld and weld history;

(6) whether original weld or repair;

(7) part and drawing number;

(8) details of visible surface imperfections.

b. Interpretation of radiographs is to be carried out only by personnel with thenecessary qualifications and experience to do so (see Clause 3.1a.). Radiographs

are to be examined and interpreted by the Examining Authority to assurecompliance with the requirements of this NES. The terminology used in thereport of interpretation of weld defects is to be that recommended in BS 499Part 1. The terminology for internal defects in castings is to be thatrecommended in BS 2737.

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10.2

FIGURE 10.1 METHOD OF MARKING WELDS FOR RADIOGRAPHY

NOTES 1. The IQI is to be placed at one or both ends of each section to be radiographed.The wires are to lie transversely across the weld with the thinest wire remotefrom the centre of the radiation beam.

2. Marker arrows that denote the length of weld under examination may alsobe used to point to the appropriate IQI wire corresponding to the sensitivityvalue required.

3. Wherever possible the minimum overlap of radiographs is to be 35mm.For pipe welds adequate coverage is to be demonstrated.

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11.1

11. IMAGE QUALITY INDICATORS

11.1 General

a. Wire complying with BS 3971 or DIN 54109 IQI are to be used to assist indetermining the quality level of all radiographs (see FIGURE 6.1 and

FIGURE 6.2).

11.2 IQI Materials

a. Selection of IQI material is to be made as follows:

(1) materials are grouped as shown in TABLE 3.1. The correct IQI series foreach material group under examination is given below and is to be usedwherever possible. If the correct IQI is not available, then an IQI of a lowerabsorption coefficient, at the lowest energy level to be used, may besubstituted provided the same measured quality level is attained;

Material Group IQI Series

1 FE

2 CU

3 AL

(2) for radiography of a material not covered by TABLE 3.1, an IQI may beused which is either manufactured from the same material or fromanother material whose radiographic absorption coefficient, at the lowestenergy level to be used, is within 15% of that of the material underexamination;

(3) for welds made between dissimilar metals in a single group perTABLE 3.1, the IQI for that group is to be used as in (1) above;

(4) for welds made between dissimilar metals not of the same group perTABLE 3.1, one IQI corresponding to the relevant group or of a lowerabsorption coefficient as in (1) is placed on each side of the joint;

(5) for welds with weld metal of a different group for the base material(s), anadditional IQI corresponding to the weld metal composition or of a lowerabsorption coefficient as in (1) is to be used.

11.3 Wire Type IQI DIN 54109

a. Each material group is covered by three IQI models which together contain aseries of 16 wires. Each IQI model contains seven wires numbered respectively1!7, 6!12 and 10!16. Wire diameters range from 1mm (wire No 1) to 0.1mm(wire No 16).

11.4 Wire Type IQI BS 3971

a. Each material group is covered by four IQI models which together contain aseries of 21 wires. Each IQI model contains seven wires numbered respectively

1!

7, 4!

10, 9!

15 and 15!

21. An additional model is included in the BS rangewhich contains all 21 wires. Wire diameters range from 0.032mm (wire No 1)to 3.2mm (wire No 21).

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11.2

11.5 IQI Identification

a. IQIs are identified by a combination of symbols which appear in the radiographeg

For DIN type IQI: DIN!62!Fe or Cu or Al

1 ISO 7 or 6 ISO 12 or 10 ISO 16For BS type IQI: Fe or Cu or Al or Mg

1!7 or 4!10 or 9!15 or 15!21 or 1!21

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12.1

12. IQI LOCATION

a. One IQI is to represent an area within which radiographic densities do not varymore than from +30% to!15% from the density measured adjacent to the IQI.

At least one IQI per radiograph is to be used except as specified in Clause 11.5g.When the film density variation is more than above, two IQIs used as follows

will be satisfactory; if one IQI shows an acceptable sensitivity at the most denseportion of the radiograph and the second IQI, placed in accordance with theother requirements of this NES, shows an acceptable sensitivity at the leastdense portion of the radiograph, these two IQIs are to serve to qualify theradiograph within these density limits.

b. The IQI is to be located on the source side of the section being examinedwherever possible.

c. For weld examination the IQI is to be placed at one or both ends of each lengthto be radiographed. The wires are to lie transversely across the weld with thethinnest wire remote from the centre beam.

d. For double-wall, double-image exposures (eg on pipe welds) the IQI is, wherepracticable, to be placed on the outside of the pipe across the weld nearest to thesource of radiation. The selected wire is to be placed over the centre line of theweld.

e. For double-wall, single-image exposures in which only the portion of the weldnext to the film is viewed, the radiographic technique is to be demonstrated ona similar test section with the applicable IQI placed on the inside compared withan IQI placed on the film side. The demonstrated radiographs are to beidentified and included with the production radiographs when these arepresented for interpretation.

f. Where a gap necessarily exists between the item under examination and thefilm, the IQI is to be placed on that part of the item furthest from the film.

g. For circumferential pipe welds, the number and location of IQIs are to be inaccordance with TABLE 12.1.

h. For longitudinal pipe welds, one IQI is to be placed ateach extremity of each filmalong the weld, and only the weld image that appears between the thinnestvisible wires of the IQIs is to be assessed.

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12.2

RADIATION PASSES THROUGH ONE WALL ONLY

PIPEDIAMETER

NUMBER OFWALLS VIEWED

FOR ACCEPTANCENUMBER AND LOCATION OF IQIs

100mm up to but

not including250mm

1 One IQI on the outside surface of the

pipe on the source side, along thecentre line of the pipe.

250mm and over 1 If the length to be inspected is lessthan 125mm, one IQI. If over125mm, two IQIs one at eachextremity of the area to be inspectedor one at the centre of the radiationbeam and one at an extremity of thearea to be inspected.

RADIATION PASSES THROUGH TWO WALLS

Under 100mm 1 or 2 One IQI on the outside surface of the

pipe on the source side along thecentre line of the pipe.

100mm up to butnot including250mm

1 See Clause 2.d. The IQI is to lie along the centre line of the pipe.

250mm and over 1 Two IQIs, one at each extremity of the area to be inspected or one at thecentre of the radiation beam and oneat an extremity of the area to beinspected.

TABLE 12.1 IQI LOCATION FOR CIRCUMFERENTIAL WELDS

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13.1

13. RADIOGRAPHY OF PIPE WELDS

13.1 Single-Wall Technique

a. Exposures are to be made through a single-wall wherever practicable. Theradiation beam is to be directed at the centre of the weld and normal to the pipe

surface at that point. Additional beam directions may, however, be necessary todetect weld fusion face defects. The SFD is to be based on the single-wallthickness in accordance with FIGURE 3.2.

13.2 Double-Wall Single-Image Technique

a. Exposures are made for the examination of the weld closest to the film. Theradiation beam is to be directed through the centre of the section beingexamined and offset from the plane through the weld by the minimum distancenecessary to avoid superimposing images. The film is to be placed diametricallyopposite the radiation source in close contact with the weld. The SFD is to bein accordance with Clause 6.10d. and FIGURE 3.2. The IQI sensitivity is to be

calculated relative to the single-wall thickness.

13.3 Double-Wall Double-Image Technique

a. Exposures are made for the examination of both walls when double-wallsingle-image exposures are not practicable. The centre line of the radiationbeam is to be directed through the centre of the pipe in the plane of the weld.The source of radiation is to be offset only by the minimum amount necessaryto avoid superimposing images. The SFD is to be in accordance withClause 6.10d.(6) and TABLE 6.2. The IQI sensitivity is to be calculated relativeto the double-wall thickness. At least three exposures will be required to covera pipe butt joint in normal practice by this method.

b. Offset is not to be employed in the radiography of consumable root inserts.

c. Generally, for pipework radiography, the recommendations in BS 2910 are toapply. Double-wall double-image exposures are to be restricted to pipes notexceeding 90mm outside diameter unless otherwise specifically approved byMOD(PE).

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13.2

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14.1

14. WELDS WITH OVERLAY CLADDING

a. Radiography is to be performed on the completed base metal weld prior tocladding.

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15.1

15. SIMULTANEOUS EXPOSURES

a. When a single film or series of films is exposed in a 360 degree radiation beamon a single component, a minimum of one IQI is to be located in each quadrant.If multiple components or parts are exposed simultaneously, at least one IQI isto be required on each film plus, where relevant, additional IQIs as required by

Clause 11.5g.

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15.2

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16.1

16. RADIOGRAPHY OF SMALL PARTS

a. At the discretion of the MOD(PE) IQIs may not be required on each film whenradiographing small parts, or limited areas of larger parts, when location of theIQI on the part would obscure part or all of the area of interest and where itwould not be practicable to place the IQI on a test section adjacent to the part.

However, an initial technique, shot, with the applicable IQI on the part, is todemonstrate the specified IQI sensitivity. Subsequent exposure without an IQIis to be made only if exposed in the same manner as the technique shot.

Whenever the arrangement is changed, additional technique shots are to bemade in proper sequence to ensure that the process is being properly controlled.The technique shots are to accompany the subsequently exposed film whenpresented for interpretation.

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17.1

17. RADIOGRAPHY OF REPAIR WELDS

a. When weld repairs to welded joints and metallic materials including castings orforgings have been made, weld repair details are to accompany the radiographswhen offered for review. The original radiographs of the previously defectivearea are also to be made available for review with the final acceptance

radiographs.

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18.1

18. RADIOGRAPHY OF CASTINGS

a. In addition to the information required in Clause 3.2i. and FIGURE 3.1, castingradiographic reports are to include a suitable sketch or drawing which includesthe following information:

(1) the classification of the casting and its unique identification;

(2) Critical Test Regions and Test Regions in accordance with NES 745Parts 1 and 2;

(3) number of films and type;

(4) location of each film on the casting;

(5) location of markers;

(6) location of radiation source including angle and source-to-film distancesrelative to each film position;

(7) voltage or isotope type and strength;

(8) details of visible surface imperfections.

18.1 Techniques

a. Radiography of Critical Test Regions is to be limited to single-wall techniquesunless this is demonstrated to be impracticable and a double-wall technique isnecessary. Test Regions may be examined by double-wall single-image anddouble-wall double-image techniques. Defects shown by double-wall exposuresmay require additional radiography to establish the severity of the defects

relative to single-wall thickness. For further guidance BS 4080 is to beconsulted.

18.2 Technique Shot Films

a. The production of films on the first casting are to be used to demonstrate theadequacy of the radiographic technique. The MOD(PE) or contractor as agreedis to approve the procedure when satisfactory quality is obtained on all filmsandthe extent of coverage required by the applicable specification or drawings hasbeen obtained.

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18.2

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A.1 ANNEX A.

ANNEX A.

RELATED DOCUMENTS

A.1 The following documents and publications are referred to in this NES:

See ClauseBS 499 Welding terms and symbols 10.b.

Part 1: Glossary for welding, brazing andthermal cutting

BS 2600 Radiographic examination of fusion weldedbutt joints in steel

6.10b., 6.10d.

Part 1: Methods for steel 2mm up to andincluding 50mm thick

Part 2: Methods for steel over 50mm upto and including 200mm thick

BS 2737 Terminology of internal defects in castingsas revealed by radiography

10.b.

BS 2910 Methods for radiographic examination offusion welded circumferential butt joints insteel pipes

13.3c.

BS 3683 Glossary of terms used in non-destructivetesting

B.1

Part 3: Radiological flaw detection

BS 3971 Specification for image quality indicatorsfor industrial radiography (includingguidance on their use)

11.1a., 11.4a.

BS 4080 Methods for non-destructive testing of steelcastings

18.1a.

DIN 54109 Image Quality Indicators of X-ray andGamma ray

11.1a., 11.3a.

NES 745 Classification, Inspection Requirementsand Acceptance Standards for Castings

1.a., 4.a.,18.a.

Part 1: Copper and Nickel Alloy Castings

Part 2: Steel Castings

DG Ships/G/10000B(NES 773*)

Minimum Acceptance Standards for Weldsin HM Ships and Submarines

1.a., 4.a.

*In course of preparation. When published will supersede stated document.

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A.2ANNEX A.

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B.1 ANNEX B.

ANNEX B.

DEFINITIONS AND ABBREVIATIONS

B.1 Definitions contained in BS 499 Part 1 and BS 3683 Part 3 are to apply to the relevantteems used in this NES. The following additional definitions are also to apply:

Maximum Effective RadiationSource Dimension

The maximum source or focal dimensionprojected on the centre of the radiographicfilm.

Multiple Film Technique A procedure in which two or more films ofthe same or different speed with therelevant intensifying screens are used inthe same film holder.

Material Thickness The thickness of the material presented forradiographic examination.

Examination Authority The Company, Organization, Establishment

or Naval Base that carries out theradiographic examination within the scopeof this Part.

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B.2ANNEX B.

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C.1 ANNEX C.

ANNEX C.

PROCUREMENT CHECK LIST

Notes:

1. This Check List is to ensure that certain aspects of this Naval EngineeringStandard are consulted when preparing a Statement of TechnicalRequirements for a particular application.

2. Clauses where a preference for an option is to be used or where specific data iso e a e are nc u e n e ec s .

3. Each item is to be marked either

! = included

NA = not applicable

CHECKNo

CHECK CLAUSE No !or NA

1 Extent of radiographic examination SCOPE 4.

2 Standards for acceptance of defect indications B.1

3 Heat treatment condition 0502

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C.2ANNEX C.

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INDEXINDEX.1

ALPHABETICAL INDEX

A

Acceptance standards, 1.1

Approval requirements

equipment, 3.3

personnel, 3.1

Audit, 3.1

C

Cassettes, 6.2

Castings, 4.1, 17.1

Conditions of issue, vi

Consumable root inserts, 12.1

Contents, ix

Co ntractual documents, 3.1

Critical test regions, 17.1

D

Darkroom facilities, 8.1

Definitions, B.1

Densitometers, 9.1

Diagnostic film length, 6.4

Direction of radiation, 6.1

D ouble-wall, d ouble-ima ge r ad iogra phy, 6.3, 6.4, 11.2, 12.1

D ouble-wall, single-image ra diogr aphy, 6.4, 11.2, 12.1

E

E ffective source dimensions, 6.4

Eq uipment q ualification, 3.3

Eq uipment used for radiographic interpretation, 9.1

Examination, extent of, iii, 2.1

Examining Authority, 3.1, B.1

E xposures, vii, 12.1, 14.1

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INDEX INDEX.2

F

Film

density, 6.2

identification, 6.5

quality, 6.1

type, 6.1viewing, 9.1

Filmless techniques, 6.3

Films, technique shot, 17.1

Filters, 6.1, 6.2

Focus to film distance, 3.5, 6.3

Fogging, 6.1

G

G amma-ray isotopes, 5.1

G amma -rays, 3.6, 3.7, 6.1

G eometric image unsharpness (U G ), 6.3

H

Hea lth and safety, ii, vii

I

Ima ge q uality indicato rs (IQ I), 6.1, 6.2, 6.3, 11.1, 11.2

Image quality level, 6.1

Inspection, 2.1, 3.1

Interpretation, 10.1

IQ I location, 11.2

Isotopes, 5.1

L

Location markers, 6.5

M

Marking welds, method, 10.2

Ma sking, 9.1

Material absorption, 3.1

Material grouping, qualification, 3.1

Material thickness, definition, B.1

Maximum effective radiation source dimension, B.1

Multiple-film techniques, 6.3, B .1

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INDEXINDEX.3

P

Personnel, qualification, 3.1

Pipe welds, 11.2, 12.1

Procedures, approval, 3.1

Procedure, standard radiographic, 3.4

Procurement check list, C.1

Q

Quality level, 6.1

R

Radiation, direction of, 6.1Radiation sources, 5.1

R adiographic absorption, 3.1

R adiographic procedure, standard, 3.4

Radiographic records, 3.1

Radiographic sketch or drawing, 17.1

R adiographs, retention period, 7.1

R adiography of small parts, 15.1

Reapproval o f radiographic procedure, 3.2

Register, 3.1

Related documents, A.1

Repa ir welds, 16.1

S

Safety, vii

Scope, iii

Screens, 6.1

Simultaneous exposures, 14.1

Single-wall, pipe welds, 12.1

Sketches, 10.1, 17.1

Small parts, 15.1

Source dimensions, 5.1

Source to film distance, 3.5, 6.3

Sources, gamma-ray, 5.1, 3.6, 3.7

Standards, acceptance, 1.1

Storage of radiographs and records, 7.1

Sub-contractor records, 7.1

Surface preparation, 4.1

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INDEX INDEX.4

T

Terminolo gy, defects, 10.1

Test regio ns, 17.1

Thickness limitations, gamma-ray sources, 5.1

W

Welds

method of marking, 10.1, 10.2

pipe, 11.2, 12.1

repair, 16.1

with overlay cladding, 13.1

X

X-ray sources, 5.1

X-ray voltage, 3.6, 3.7, 5.1

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Inside Rear Cover

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