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AS 2452.1—2004

Australian Standard™

Non-destructive testing—Determinationof thickness

Part 1: Determination of wall thicknessof pipe by the use of radiography

A S 2 4 5 2 .1 —2 0 0 4

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o n 2 7 M a r 2 0 1 3 ( D o c u m e n t c u r r e n c y n

o t g u a r a n t e e d w h e n p r i n t e d )



This Australian Standard was prepared by Committee MT-007, Non-DestructiveTesting of Metals and Materials. It was approved on behalf of the Council ofStandards Australia on 15 October 2004.This Standard was published on 1 November 2004.

The following are represented on Committee MT-007:

ANSTO

Australian Aerospace Non-Destructive Testing Committee

Australian Industry Group

Australian Institute for Non-Destructive Testing

Australian Pipeline Industry Association

Australian Railway Association

Bureau of Steel Manufacturers of AustraliaInstitution of Engineers Australia

National Association of Testing Authorit ies Australia

TestSafe Australia

Victoria Workcover Authority

Welding Technology Institute of Australia

Keeping Standards up-to-date

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Detailed information about Standards can be found by visiting the Standards WebShop at www.standards.com.au and looking up the relevant Standard in the on-linecatalogue.

Alternatively, the printed Catalogue provides information current at 1 January each year, and the monthly magazine, The Global Standard , has a full listing of revisionsand amendments published each month.

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and other products and services developed by StandardsAustralia are published and distributed under contract by SAI Global, whichoperates the Standards Web Shop.

We also welcome suggestions for improvement in our Standards, and especiallyencourage readers to notify us immediately of any apparent inaccuracies orambiguities. Contact us via email at [email protected], or write to the ChiefExecutive, Standards Australia International Ltd, GPO Box 5420, Sydney, NSW2001.

This Standard was issued in draft form for comment as DR 03553.

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AS 2452.1—2004

Australian Standard™

Non-destructive testing—Determinationof thickness

Part 1: Determination of wall thicknessof pipe by the use of radiography

Originated as AS 2452.1—1982.Second edition 2004

COPYRIGHT

© Standards Australia International

All rights are reserved. No part o f this work may be reproduced or copied in any form or by

any means, electronic or mechanical, including photocopying, without the written

permission of the publisher.

Published by Standards Australia International Ltd GPO Box 5420, Sydney, NSW 2001,

Australia

ISBN 0 7337 6343 X

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AS 2452.1—2004 2

PREFACE

This Standard was prepared by the Joint Standards Australia/Standards New Zealand

Committee MT-007, Non-Destructive Testing of Metals and Materials, at the request ofindustry. This Standard supersedes AS 2452.1 1982, Non-destructive testing

Determination of thickness, Part 1: Determination of wall thickness of pipe by the use of

radiography.

This Standard was prepared by the Australian members of the Joint Standards

Australia/Standards New Zealand Committee MT-007. After consultation with shareholders

in both countries, Standards Australia and Standards New Zealand decided to develop this

Standard as an Australian Standard rather than an Australian/New Zealand Standard.

The objective of this Standard is to specify methods for film radiography to determine wall

thickness of pipes and small fabricated vessels.

The objective of this revision is to expand the technology for the equipment and accessoriesused for radiography in determining wall thickness.

The methods in this Standard provide suitable bases for the testing of round pipe or other

small pressure vessels, including gas cylinders. The methods rely on the use of a source of

radiation, X-rays or gamma-rays, and require testing personnel to be experienced in the

handling and use of radiation equipment and materials.

This Standard is Part 1 of a series of Standards covering the radiography of ferrous

castings.

The series comprises the following parts:

AS

2452 Non-destructive testing

Determination of thickness2452.1 Part 1: Determination of the wall thickness of pipe by the use of radiography

2452.3 Part 3: Use of ultrasonic testing

The term ‘normative’ has been used in this Standard to define the application of the

appendix to which it applies. A ‘normative’ appendix is an integral part of a Standard.

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3 AS 2452.1 — 2004

CONTENTS

Page

1 SCOPE........................................................................................................................ 4

2 REFERENCED DOCUMENTS.................................................................................. 4

3 SAFETY PRECAUTIONS ......................................................................................... 4

4 DEFINITIONS............................................................................................................ 4

5 PRINCIPLE ................................................................................................................ 5

6 EQUIPMENT AND ACCESSORIES ......................................................................... 5

7 PROCEDURE............................................................................................................. 6

8 MEASUREMENTS AND CALCULATION .............................................................. 9

9 QUALIFICATION OF NON-DESTRUCTIVE EXAMINATION PERSONNEL....... 9

10 TEST REPORT........................................................................................................... 9

APPENDIX A APPROXIMATE CHORD LENGTHS FOR SOME TYPICAL

PIPE SIZES ...............................................................................................................16

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AS 2452.1 — 2004 4

© Standards Australia www.standards.com.au

STANDARDS AUSTRALIA

Australian Standard

Non-destructive testing—Determination of thickness

Part 1: Determination of wall thickness of pipe by the use of radiography

1 SCOPE

This Standard specifies the methods for the determination of the wall thickness of pipes and

small fabricated vessels using X-ray or gamma-ray radiography.

NOTES:

1 Under a given set of radiographic conditions, the accuracy of the methods specified herein is

reduced with decreasing wall thickness and with increasing pipe or vessel diameter.

2 The methods specified herein are more accurate when a pipe is empty.

2 REFERENCED DOCUMENTS

The following documents are referred to in this standard:

AS

1929 Non-destructive testing — Glossary of terms

2243 Safety in laboratories

2243.4 Part 4: Ionizing radiations

3998 Non-destructive testing — Qualification and certification of personnelCode of Practice for the Control and Safe Handling of Sealed Radioactive Sources Used in

Industrial Radiography*

NH and MRC Radiation Health Series No. 31, Code of Practice for the safe use of

Industrial Radiography Equipment

3 SAFETY PRECAUTIONS

Exposure of any part of the human body to ionizing radiation may be injurious. It is

therefore essential that when X-ray equipment or radioactive sources are being used

adequate precautions be taken to protect testing personnel and any other persons in the

vicinity. NOTE: The use of radioactive substances and irradiating apparatus is controlled by various

statutory regulations. Reference should also be made AS 2243.4, the ‘Code of Practice for the

Control and Safe Handling of Sealed Radioactive Sources used in Industrial Radiography’ and

NH and MRC Radiation Health Series No.31 ‘Code of Practice for the safe use of Industrial

Radiography Equipment’.

4 DEFINITIONS

For the purposes of this Standard, the terms and definitions given in AS 1929 apply.

* Issued by the National Health and Medical Research Council, Canberra. A c c e s s e d b

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5 AS 2452.1 — 2004

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5 PRINCIPLE

An image of the tangential section of a pipe produced on a radiographic film positioned

with its plane approximately normal to the path of the beam of radiation on the opposite

side. The wall thickness of the pipe at the point which is tangential to the beam is

determined from the resultant film images by the use of appropriate equations.

6 EQUIPMENT AND ACCESSORIES

6.1 General

The radiographic testing system shall be capable of delineating boundaries and contours,

determining wall thickness of pipes of small fabricated vessels, and of producing

satisfactory image quality in a radiograph.

6.2 X-ray equipment

X-ray equipment up to 450 kV shall be used. The exposure shall be carried out at the lowest

voltage consistent with a reasonable time.

6.3 Gamma-ray sources

Gamma-ray sources given in Table 6.1 may be used for penetrating the approximate

thickness of steel specifications.

NOTE: Methods using gamma-rays are usually less sensitive than methods using X-rays.

TABLE 6.1

GAMMA-RAY SOURCE FOR THE TESTING OF STEEL

Approximate thickness of steel*

mmGamma-ray source

min. max.

Cobalt 60 (Co60) 50 200

Iridium 192 (Ir192) 10 90

Ytterbium 169 (Yb169) 6 20

* Values of thickness are generally regarded as those values above which exposure times

will be unreasonably long and below which the required quality may not be readily

achieved.

6.4 Intensifying screens

Metal intensifying screens emit electrons under irradiation and the action of these electrons

on the film contributes to producing a chosen density of radiograph with a shorter exposuretime. Screens are used to minimize scatter radiation. The following recommendations apply

to screens:

(a) Screens shall be handled carefully to avoid dents, creases, scratches and

contamination by dirt and grease.

(b) Any damaged screens which produce a spurious image in the section under test on the

radiographic film shall not be used.

(c) Foreign material such as grease or lint shall be removed with care from the surface of

the screen.

6.5 Cassettes

Irrespective of the type of cassette used, adequate precautions shall be taken to ensure good

film-to-screen contact. Rigid cassettes may be necessary to maintain a fixed position in

relation to the beam, especially where it is difficult to obtain film/screen contact. A c c e s s e d b

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AS 2452.1 — 2004 6


6.6 Radiographs

All radiographs shall be free from mechanical, chemical, or other blemishes to the extent

that they cannot mask or be confused with the image of any wall thickness changes in the

test area.

7 PROCEDURE

7.1 General

7.1.1 Arrangement

The radiation source, the area of interest and the radiographic film shall be arranged in

accordance with the method chosen (see Figures 1 to 6).

NOTE: Vibration may effect the sharpness of the image.

7.1.2 Source-to-object distance

The distance of the radiation source to the edge of the area of interest shall be not less than

5 times the distance of the tangent point to the plane of the film. NOTE: This ratio should be increased proportionately with sources larger than 2 mm.

7.1.3 Exposure for steel

Exposure shall be selected to produce a film image of the area of interest which may be

satisfactorily measured. Consequently it is not necessary to achieve the radiographic density

levels used for the detection of discontinuities in normal radiography.

Dimensions of chord lengths for typical pipe sizes are given in Appendix A.

NOTE: Exposure charts (see Figures 7 and 8) are provided for steel using the following sources

of radiation:

(a) Ir192

.

(b) Co60.

These charts give exposures which have been found by experience for the various chord lengths

of a range of sizes of steel pipe. An alternative procedure involves the use of conventional

exposure charts (pipe thickness vs exposure) prepared for the type of radiation source it is

proposed to use.

7.1.4 Radiographic equivalence factors

Exposures for materials other than steel may be calculated by multiplying the section

thickness by the Radiographic Equivalence Factor (Table 7.1) and referring to the

appropriate exposure curve for steel.

7.1.5 Film processing

Normal film processing shall be carried out in accordance with the instructions of the film

manufacturer.

7.2 Method No.1

7.2.1 Application

This method is suitable for use on unlagged piping up to 300 mm in diameter where the

pipe axis can be aligned with the source.

7.2.2 Procedure

The procedure shall be as follows:

(a) Estimate minimum film size required from pipe diameter and source-to-film distance.

(b) Position the cassette so that axis of the beam of radiation is normal to the plane of the

cassette through the centre of the pipe (see Figure 1). A c c e s s e d b

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7 AS 2452.1 — 2004


(c) Make the exposure and measure the image of the wall thickness, m.

(d) Calculate wall thickness t according to the equation given in Figure 1.

7.3 Method No. 2

7.3.1 Application

This method is suitable for use on unlagged piping of all dimensions. In this method the

beam is normal to the film on one side but is offset from the pipe axis.

7.3.2 Procedure


(a) Estimate the minimum film size required from the pipe diameter and from the

estimated wall thickness.

(b) Arrange the source in the offset position so that the angle of the beam of radiation

approximately bisects the wall thickness t to be measured.

NOTE: The beam may be positioned on either side , as required.

(c) Position the cassette so that the angle of the beam of radiation is at right-angles to the

plane of the cassette (see Figure 2).

(d) Make the exposure and measure the image of the wall thickness, m.

(e) Calculate t according to the equation relevant to the beam angle in Figure 2.

7.4 Method No.3

7.4.1 Application

This method is suitable for use on lagged piping where the diameter of the pipe and its

position within the lagging is known.

NOTE: The method may also be used on unlagged piping.7.4.2 Procedure


(a) Estimate the minimum film size required from the pipe diameter and from the

thickness of the lagging.

(b) Arrange the source in the offset position. Let the distance from the centre-line

through the pipe equal h.

(c) Position the cassette so that the plane of the film is normal to the centre-line through

the pipe (see Figure 3).

(d) Make the exposure and measure the image of the wall thickness, m.

(e) Calculate wall thickness t according to formula (see Figure 3).

7.5 Method No. 4

7.5.1 Application

Suitable for use on lagged piping where the pipe diameter and its position within the

lagging is unknown.

7.5.2 Procedure


(a) Position the cassette so that it is held on a radius equivalent to the distance from thesource to the film b (see Figure 4).

(b) Measure b and outside diameter DL over the lagging. A c c e s s e d b

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AS 2452.1 — 2004 8


(c) Make the exposure and measure the image of the wall thickness, m.

(d) Calculate wall thickness t according to the equation in Figure 4.

7.6 Method No. 5

7.6.1 ApplicationThis method is suitable for use on small piping.

7.6.2 Procedure


(a) Measure outside diameter of pipe D.

(b) Position to cassette so that it is held on a suitable radius from the source (see

Figure 5).

(c) Make the exposure and measure the width of the diametral image D1 and the image of

the wall thickness, m.


TABLE 7.1

APPROXIMATE RADIOGRAPHIC EQUIVALENCE

FACTORS RELATIVE TO STEEL

X-rays Gam ma-rays

Material 100

kV

140

kV

220

kV

250

kVCo60 Ir192 Yb169

Aluminium (1100) 0.08 0.12 0.18 — 0.35 0.35 —

Aluminium (2024) 0.12 0.13 0.14 — 0.35 0.35 —

Carbon steel 1.0 1.0 1.0 1.0 1.0 1.0 1.0

Stainless steel (18-8) 1.0 1.0 1.0 1.0 1.0 1.0 1.0

Copper 1.5 1.5 1.4 1.4 1.1 1.2 1.3

Monel 1.7 1.5 1.2 — — — —

Lead — 14.0 11.0 — 2.3 4.0 7.0

Titanium — — 0.54 — 0.9 0.9 —

Concrete 0.09 — — 0.1 0.2 0.25 —

7.7 Method No. 67.7.1 Application

This method is suitable as a routine method where appropriate bar clamps may be fabricated

observing the constraints of the method.

7.7.2 Procedure

(a) Position cassettes in holders on ends of square bars. Slip over pipe as shown. Use

spring clamp to firmly hold device (see Figure 6).

NOTE: Posit ion clamp so as not to interfere with line of sight of the beam.

(b) Adjust the bar clamp so that both cassette holders are in contact with the pipe, and the

source holder is 5 times pipe diameter from films.(c) Make the exposure and measure the image of the wall thickness, m.

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9 AS 2452.1 — 2004



NOTE: In practice no correction is generally necessary.

8 MEASUREMENTS AND CALCULATION

8.1 Measurement

The image of the thickness of the area of interest shown on the radiograph shall be

measured using any means appropriate to the order of accuracy required.

8.2 Calculation

The actual wall thickness shall be calculated using the appropriate formula for the method

used (see Table 8.1).

TABLE 8.1

WALL THICKNESS FORMULAS

Figure number Equation

1 t = m × a/b sin θ

2 (LHS) t = m × a/b

2 (RHS) t = m1

R × (a1

R /b1

R ) × sin θ

3( ) ( )

H

Dhmt

θ θ θ tan2/sin/sin 2

+×

=

4 )/2

b DL

bmt

−=

5 t = m × D/D 1

6 t = m × a/b

9 QUALIFICATION OF NON-DESTRUCTIVE EXAMINATION PERSONNEL

Radiographic examination, interpretation, evaluation for compliance, and report shall be

made by personnel having qualifications and experience for their job function acceptable to

the testing body, the manufacturer and where required by the purchaser.

Operators shall have the qualifications detailed below or shall carry out their duties under

the supervision of persons responsible for the examination.

Qualifications normally acceptable for the examination of components include the

following:

(a) Certification by the Australian Institute of Non-Destructive Testing (AINDT) in

accordance with AS 3998 in the radiographic testing of ferrous castings.

(b) Equivalent qualifications.

10 TEST REPORT

The test report shall include the following information:

(a) Identification of the radiographic laboratory.

(b) Product identification or job description, including material and nominal pipe or

vessel diameter and location.

(c) Radiation source.

(d) Film type, exposure, and, if applicable, the relevant exposure-value.

(e) Source-to-object distance and source-to-film distance. A c c e s s e d b

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AS 2452.1 — 2004 10


(f) The method used.

(g) Chord length, in millimetres.

(h) Wall thickness, as measured on the radiographic film, in millimetres.

(i) Calculated wall thickness, in millimetres(j) Reference number of this Australian Standard, i.e. AS 2452.2.

(k) Report number and date.

FIGURE 1 ARRANGEMENT FOR METHOD 1

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AS 2452.1 — 2004 12




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AS 2452.1 — 2004 14


FIGURE 7 EXPOSURE CHART FOR IRIDIUM 192, FOR STEEL

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15 AS 2452.1 — 2004


NOTES:

1 The broken line shows theoretical exposure values. Exposure values found satisfactory in practice are

represented by the solid line.

2 For method of calculation of chord length see Figure 7.

FIGURE 8 EXPOSURE CHART FOR COBALT-60 FOR STEEL

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AS 2452.1 — 2004 16


APPENDIX A

APPROXIMATE CHORD LENGTHS FOR SOME TYPICAL PIPE SIZES

(Normative)

Standard (STD)

X-Strong (XS)

XX-Strong (XXS)

Nominal

pipe

size*

Outside

diameter

Wall

thickness

Approximate

chord

length†

mm mm

Pipe

schedule

or strength

mm mm

19.1

(3/4)

26.67 40, STD

80, XS

160 XXS

2.87

3.91

5.41

7.82

17

19

21

24

25

(1)

33.4 40, STD

80, XS

160 XXS

3.38

4.55

6.35

9.09

20

23

26

30

50.8

(2)

60.3 40, STD

80, XS

160 XXS

3.91

5.54

8.74

11.07

30

35

42

47

76.2

(3)

88.9 40, STD

80, XS

160 XXS

5.49

7.62

11.13

15.24

43

50

59

67

101.6

(4)

114.3 40, STD

80, XS

120

160 XXS

6.02

8.56

11.13

13.49

17.12

51

60

68

74

82

127

(5)

141.3 40, STD

80, XS

120

160 XXS

6.55

9.53

12.70

15.88

19.05

60

71

81

89

97

152.4

(6)

168.3 40, STD

80, XS120

160 XXS

7.11

10.9714.27

18.34

21.95

68

8394

105

113

203.2

(8)

219.1 30

40, STD

60

80, XS

XXS

7.04

8.18

10.31

12.70

22.23

77

83

93

102

132

(continued)

* Figures in brackets refer to imperial inch measurements; they have been

included for convenience of use of the table.

† Rounded to nearest millimetre.

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17 AS 2452.1 — 2004


Standard (STD)

X-Strong (XS)

XX-Strong (XXS)

Nominal

pipe

size*

Outside

diameter

Wall

thickness

Approximate

chord

length† mm mm

Pipe

schedule

or strengthmm mm

254

(10)

273.1 30

40, STD

60, XS

80

7.8

9.27

12.70

15.06

91

99

115

125

304.8

(12)

323.9 30

STD

40 XS

60

80

8.38

9.53

10.31

12.70

14.27

17.45

103

109

114

126

133

146

355.6(14)

355.6 2030, STD

40 XS

60

80

7.929.53

11.13

12.70

15.06

19.05

105115

124

132

143

160

406.4

(16)

406.4 20

30, STD

40, XS

60

80

7.92

9.53

12.70

16.66

21.41

112

123

141

161

182

457.2

(18)

457.2 20

STD30 XS

40

60

80

7.93

9.5211.13

12.70

14.27

19.05

23.82

119

131141

150

161

183

203

508

(20)

508 10

20, STD

30, XS

40

60

80

6.35

9.53

12.70

15.06

20.62

26.19

113

138

159

172

200

225

558.8

(22)

558.8 STD

XS

9.53

12.70

145

167

609.6

(24)

609.6 10

20, STD, XS

30

40

60

6.35

9.53

12.70

14.27

17.45

24.59

124

151

174

184

203

240

660.4

(26)

660.4 STD

XS

9.53

12.70

158

181

(continued)

* Figures in brackets refer to imperial inch measurements; they have been

included for convenience of use of the table.† Rounded to nearest millimetre.

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NOTES

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Determination of Thickness by RT