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Guided Ultrasonics Ltd.

Wavemaker G3TM

Procedure Based Inspector Training Manual

Copyright c©1999-2007 by Guided Ultrasonics Ltd.All Rights Reserved.

No part of this document except for the Appendices may be reproduced or transmitted in any from orby any means electronic or mechanical, including photocopy, recording, or any information storage and

retrieval system, without permission in writing fromGuided Ultrasonics Ltd.

Guided Ultrasonics Ltd.17 Dover Beck Close

RavensheadNottingham, UK

NG15 9ER

+44 (0) 1623 491 [email protected]

www.guided-ultrasonics.com

Document created using LATEX on May 31, 2007

Wavemaker is a registered trademark of Guided Ultrasonics Ltd.All other trademarks are owned by their respective owners.

Warning: The procedure outlined in this document is only to be used as an example thatwill give guidance to operators when constructing their own procedures. Following thisprocedure in no way ensures that corrosion / defects / problems / etc. will be found in

the pipes that are screened. Procedures need to be adjusted for conditions that areexperienced on site.

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Contents

1 Introduction 11.1 Intended Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Overview of the method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3 How the test is performed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.3.1 Equipment preparation prior to inspection . . . . . . . . . . . . . . . . . . . . . . . 31.3.2 Pipe preparation prior to inspection . . . . . . . . . . . . . . . . . . . . . . . . . . 31.3.3 Dead zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3.4 Configuration of test parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3.5 Reproducibility of the test result . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3.6 View of Processed Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3.7 Interpretation of the results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.4 Formatting Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.5 Basic navigation - G3 instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2 Initial Setup 72.1 System requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72.2 Installing WaveProG3 software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.2.1 Installation from the G3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.2.2 Installation via CD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.2.3 Installation via the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.3 Running WaveProG3 without an instrument . . . . . . . . . . . . . . . . . . . . . . . . . . 92.4 Upgrades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.4.1 Licence upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102.4.2 WaveProG3 upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3 Preparing for a Job 113.1 Assessing the job . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.2 Frequency regime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.3 Selection of transducer rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.3.1 Solid Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133.3.2 Inflatable Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.4 Test ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183.4.1 End of Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3.5 Packing for the job . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193.6 Wavemaker G3 instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

3.6.1 Charging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203.6.2 Turning On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223.6.3 Turning Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233.6.4 Logging On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233.6.5 Basic Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243.6.6 Open Box Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243.6.7 Desiccant Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253.6.8 USB Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3.7 Ring cable checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273.8 Transducer rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

3.8.1 Physical checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

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3.8.2 Electrical checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

4 Preparing Location 354.1 Select test location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354.2 Clean pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364.3 Check location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

4.3.1 Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374.3.2 Thickness check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

4.4 Apply transducer rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394.4.1 When using solid rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394.4.2 For inflatable rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404.4.3 For combined inflatable rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

4.5 Connecting to the G3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424.5.1 G3/Ring connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424.5.2 Initial Coupling Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

5 Collecting Data 445.1 Checking parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

5.1.1 Ring parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445.1.2 Battery and Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445.1.3 Capacitance and Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

5.2 Collection protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455.3 Starting a test from the PC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465.4 Starting a test from the Wavemaker G3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475.5 Check transducer ring operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

5.5.1 Raw Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495.5.2 Ambient Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495.5.3 Calibration data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

6 Analysis Tools 536.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536.2 Reflected Amplitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

6.2.1 DAC Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536.2.2 Manually Adjusting DAC Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566.2.3 Cross sectional area change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6.3 Symmetry / Circumferential Extent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 586.4 Shape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 606.5 Orientation / Unrolled Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 616.6 Frequency Dependence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

6.6.1 Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 636.7 Phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

7 Level 1 Data Analysis 657.1 Interpretation overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

7.1.1 Basic presentation of the data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 667.2 Identify welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 687.3 Mark any embedded sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 687.4 Set the DAC curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

7.4.1 Automatic DAC Fit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 697.4.2 Feature Dependent Decay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 707.4.3 Determining end of test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 717.4.4 Save results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

7.5 Classify other reflections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 717.5.1 Examine other features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 727.5.2 Check for False Echoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

7.6 Perform test from other side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 777.7 Classification of echoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

7.7.1 Corrosion classifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

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7.7.2 Review of terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787.8 Make overall notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797.9 Identify any required follow up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797.10 Move to next test location and repeat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

8 Reporting Results 818.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 818.2 The report screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

8.2.1 Print options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 828.2.2 View Preferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

8.3 The images screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 888.4 The summary screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 888.5 Backing up results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 908.6 Printing and exporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

8.6.1 Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 918.6.2 Exporting to PDF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 918.6.3 Exporting to Word processors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

9 Maintenance 939.1 End of day servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

9.1.1 Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 939.1.2 Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 939.1.3 Wavemaker G3 Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 949.1.4 Wavemaker WaveProG3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 949.1.5 Short Term Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

9.2 Monthly maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 949.2.1 Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 949.2.2 Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 959.2.3 Wavemaker G3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 959.2.4 Wavemaker WaveProG3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

9.3 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 959.4 Shipping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

A Specifications 97A.1 General Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97A.2 CE Compliance Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99A.3 FCC and FDA Notices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

A.3.1 Federal Communication Commission . . . . . . . . . . . . . . . . . . . . . . . . . . 100A.3.2 Food and Drug Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

B Safety Summary 101B.1 Plant issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101B.2 Personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

C Glossary 103

D Training Scheme 106D.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106D.2 GUL qualification levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107D.3 Viewing an operator’s qualification level . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

E Application Levels 108

F Index 111

iv

List of Tables

3.1 Example questions to ask during a pipe survey. . . . . . . . . . . . . . . . . . . . . . . . . 123.2 Recommended frequency regimes for various application areas. The regimes are labeled as

low(< 0), standard(0-6), high(6-12), and v.high(> 12). . . . . . . . . . . . . . . . . . . . . 163.3 The design dimensions and frequency regimes of various configurations of solid transducer

rings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.4 Types of modules used in inflatable rings. . . . . . . . . . . . . . . . . . . . . . . . . . . . 173.5 The frequency regimes for various module width configurations and various pipe diameters.

(Please note that the 70 spacing is not recommended.) . . . . . . . . . . . . . . . . . . . . 183.6 Average lengths of pipes that can be inspected from one location (in either direction) in the

standard frequency regime. Associated average attenuations are also given for reference(assuming a typical 40 dB of usable scale with the Wavemaker R©G3). . . . . . . . . . . . . 19

3.7 A packing list of items that typically required on site. . . . . . . . . . . . . . . . . . . . . 213.8 Physical checks to perform on Solid rings (see figure 3.2 for location information). . . . . 293.9 Physical checks to be performed on an inflatable ring (please refer to figure 3.3 for a

diagram showing the layout of an inflatable ring). . . . . . . . . . . . . . . . . . . . . . . . 30

4.1 Maximum warranty temperatures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

6.1 Summary of Interpretation Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

7.1 Example of how the interpretation skills apply to welds and flanges. . . . . . . . . . . . . 68

8.1 Descriptions of the feature information columns. . . . . . . . . . . . . . . . . . . . . . . . 838.2 Descriptions of the logo formatting fields. . . . . . . . . . . . . . . . . . . . . . . . . . . . 858.3 Descriptions of the report formatting fields. . . . . . . . . . . . . . . . . . . . . . . . . . . 858.4 Descriptions of the report option fields. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 868.5 Descriptions of the report graph formats. . . . . . . . . . . . . . . . . . . . . . . . . . . . 868.6 Descriptions of the summary information columns. . . . . . . . . . . . . . . . . . . . . . . 91

v

List of Figures

1.1 Schematic diagram showing the major components of the Wavemaker G3 system in atypical test configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2 Schematic diagram showing the clearance that is normally required around a pipe. . . . . 31.3 Overview of the front panel of the Wavemaker R©G3. . . . . . . . . . . . . . . . . . . . . . 6

2.1 The WaveProG3 installation dialog. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.1 Effect of changing the frequency regime. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143.2 Schematic diagram of a solid ring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153.3 Schematic diagram of an inflatable ring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173.4 The ’ID:Logon’ screen on the Wavemaker R©G3. . . . . . . . . . . . . . . . . . . . . . . . . 233.5 The (a) ’Info:Stats’ and (b) ’Info:Versions’ screens on the Wavemaker R©G3. . . . . . . . . 243.6 The ’Check:Cards’ screen on the Wavemaker R©G3. . . . . . . . . . . . . . . . . . . . . . . 253.7 The position of the desiccant container within the Wavemaker R©G3 box. . . . . . . . . . . 263.8 Correct a) insertion and b) removal techniques for the main ring cables. . . . . . . . . . . 273.9 How the cable should be connected to perform a cable check. . . . . . . . . . . . . . . . . 283.10 The ’Check:Cables’ screen on the Wavemaker R©G3. In this case, there is a major problem

with channel 3 of the cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283.11 Schematic diagram of how the modules are fitted onto an inflatable ring. . . . . . . . . . . 313.12 The ’Ring:Ring ID’ screen on the Wavemaker R©G3. . . . . . . . . . . . . . . . . . . . . . . 323.13 The ’Ring:Impedance’ screen on the Wavemaker R©G3. . . . . . . . . . . . . . . . . . . . . 323.14 Relationship between the pins in the 24 pin Lemo R© connectors (as view from the outside)

and the segments to which they direct signals. . . . . . . . . . . . . . . . . . . . . . . . . . 333.15 The ’Ring:Coupling’ screen on the Wavemaker R©G3 when an individual transducer is being

rubbed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.1 (a) Preparation of test location and (b) necessary clearance required around pipe at testlocation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

4.2 Fitting a solid ring to a pipe. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404.3 The ’Ring:Coupling’ screen on the Wavemaker R©G3 when the pipe is being rubbed with a

metal object. In this example, there is a fault on the first channel of the ring. . . . . . . . 43

5.1 An example ’Collect’ screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455.2 The ’Go’ screens that are used to start a collection from the Wavemaker R©G3 instrument. 485.3 The sequence complete screen on the G3. . . . . . . . . . . . . . . . . . . . . . . . . . . . 485.4 Example of the plot of the raw data traces. . . . . . . . . . . . . . . . . . . . . . . . . . . 505.5 The effect of having poor data from one channel. . . . . . . . . . . . . . . . . . . . . . . . 505.6 An example of the plot of the calibration data (in the time domain) when there is little

ambient noise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 525.7 An example plot of the calibration data when there is high ambient noise in the pipe. . . 52

6.1 The Configure:DAC Levels dialog. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566.2 Display with the Horizontal and Vertical components separated. . . . . . . . . . . . . . . 586.3 How circumferential extent is estimated. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 596.4 An example trace highlighting various feature characteristics. . . . . . . . . . . . . . . . . 606.5 Example of the unrolled pipe display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

vi

7.1 An example ’Analysis’ screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 667.2 Pipe diagram, showing features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 677.3 Pipe features toolbar. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 677.4 An example trace highlighting feature characteristics. . . . . . . . . . . . . . . . . . . . . 697.5 The Feature Properties dialog. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 707.6 An example of how the end of test range (for a given sensitivity) is determined. . . . . . . 727.7 An example of stacked plot helping to identify a mirror. . . . . . . . . . . . . . . . . . . . 747.8 A diagram showing the wave paths for a reverberation and how it is processed in the results. 757.9 An example trace that shows multiple equally spaced reverberations (r1, r2, and r3) as

well as a small mirror (equally spaced around the origin as a real feature (m1=m2). . . . 767.10 An example trace that shows the effects of severe modal noise. . . . . . . . . . . . . . . . 77

8.1 An example ’Report’ screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 828.2 The File:Print Options dialog. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 848.3 The View:Preferences dialog in Wavemaker R© WaveProG3

TM. . . . . . . . . . . . . . . . 87

8.4 An example ’Images’ screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 898.5 Wavemaker R© WaveProG3

TMdirectory structure. . . . . . . . . . . . . . . . . . . . . . . . 89

8.6 An example ’Summary Screen’. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

C.1 Naming convention for the axial and circumferential directions. . . . . . . . . . . . . . . . 104C.2 Definition of circumferential extent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104C.3 Examples of cross section loss versus wall loss. . . . . . . . . . . . . . . . . . . . . . . . . 105

vii

Chapter 1

Introduction

1.1 Intended Audience

This manual for the Wavemaker R©G3 Pipe Screening System is structured to resemble a generic testingprocedure that is used by Level 1 inspectors.

The chapters follow the order of actions that are typically performed by a Level 1 inspector to performa long range guided wave inspection using the Wavemaker R©G3. Each chapter gives detailed informationabout how each step of the general procedure is to be carried out. Since the manual is structured tofollow the sequential order of a test, it may be necessary for a trainee to jump forward and backward toaccess definitions of various terms. Links to forward sections are provided to help with this operation. Itis assumed that the reader has a good grasp of using the Microsoft Windows R©operating system.

Whenever possible, the authors have tried to cite the best practices for the use of this guided waveequipment. The generic procedure discussed in this manual should be adapted for specific site conditionsand expected defect types. Some of the variations are mentioned within this text. However, many testscenarios are beyond the scope of this procedure and beyond the scope of a level 1 operator. Appendix Elists what testing situations are suitable for a level 1 operator and which require an operator with level2 training (or specific training for a particular test situation).

Warning: Following this procedure in no way ensures that corrosion / defects / problems/ etc. will be found in the pipes that are screened.

This procedure has been configured for the Wavemaker R©G3 instrument, software, and training package.The same level of operation will not be possible if any of these core components are missing.

The following sections of this chapter provide an overview of how the Wavemaker R©G3 operates (section1.2), a glossary of definitions (section C), and the basic instructions for navigating around the instrument(section 1.5). A reader who is anxious to get started, can proceed directly to chapter 2.

1.2 Overview of the method

The Wavemaker R©G3 Pipe Screening System uses guided waves to screen long lengths of pipes for corrosionor cracks. Conventional ultrasonic testing such as thickness gauging uses bulk waves and only tests theregion of structure immediately below the transducer. Therefore, it is an extremely slow process to scana large structure and it is frequently necessary to resort to testing at a grid of points and hoping thatthey are representative of the whole structure.

Copyright c©1999-2007. Guided Ultrasonics Ltd. All rights reserved. The information contained within this manual is considered confidential and subject to confidentialityagreements between GUL and other parties. It may not be reproduced or distributed without prior approval from GUL.

(WavemakerR©G3 Procedural User Manual Rev 3 - May 31, 2007)

1.2 Overview of the method 2

Bend

Welds

Wavemaker transducer

ring

Wavemaker instrument

Weld

Weld

Corrosion

Support

Corrosion

Computer

(a)

(b)

Am

plit

ud

eDistance

Welds at bend

Weld Weld

Corrosion CorrosionSupport

Ringposition

Deadzone

Figure 1.1: Schematic diagram showing the major components of the Wavemaker G3 system in a typicaltest configuration.

However, even this strategy breaks down when part of the structure is inaccessible because it is eitherburied or covered in insulation. It is much more attractive to be able to screen a large area of structurefrom a single transducer location, and this is possible using guided waves which propagate along thestructure. The Wavemaker R©G3 Pipe Screening System uses special arrays of transducer elements, referredto as rings, which fit around the pipe under test. After a ring has been fitted around a pipe, the operatoruses the Wavemaker system to perform a single test that screens a number of meters of pipe on eitherside of the test location.

The length of pipe that can be effectively screened on either side of the test location in a single testdepends on numerous factors and typically ranges from several tens of meters for pipes in good conditiondown to a few meters for pipes in poor condition or with certain types of coatings. In order to understandhow the Wavemaker system works, the whole ring of transducer elements may be regarded as behavinglike a conventional ultrasonic transducer operating in pulse-echo mode. The ring sends out a burst ofultrasonic waves. These waves are guided by the boundaries of the pipe so that there is no beam spread.Whenever there is a change in cross section or stiffness of the pipe, some of the energy is reflected back.These reflected signals are detected and used to determine where any changes occur.

Figure 1.1(a) shows a schematic diagram of the ring of the Wavemaker system operating on a typicalpipe that contains an assortment of features around the test location. A schematic of the correspondingresults are shown in figure 1.1(b).

The Wavemaker system is composed of three primary components, labelled in 1.1(a) as the transducerring, the Wavemaker instrument, and the controlling computer. The transducer rings are specific to acertain pipe size. They use either springs or air pressure to dry couple piezoelectric transducer elements tothe pipe being inspected. Internal circuitry allows each transducer ring (and therefore the diameter of thepipe being tested) to be automatically detected by the electronics. All of the signal generation and detec-tion is housed in the Wavemaker R©G3 instrument, which operates from an internal rechargeable batteryand is connected to a standard laptop PC via a USB connection. The control of the instrument as well asthe signal processing and report sheet generation is done via the Wavemaker R© WaveProG3

TMsoftware

(although when access is limited, the Wavemaker R©G3 instrument can collect data independently).



1.3 How the test is performed 3

Figure 1.2: Schematic diagram showing the clearance that is normally required around a pipe.

1.3 How the test is performed

1.3.1 Equipment preparation prior to inspection

The configuration of the equipment and the choice of transducer rings varies depending on items such asthe pipe diameter, pipe condition, coatings, type of supports, and suspected type of defect. In order toobtain optimum results, the GUL operator will usually complete a test preparation sheet in co-operationwith the customers before starting the inspection.

1.3.2 Pipe preparation prior to inspection

In general very little surface preparation is required for testing using this technique because the operatingfrequency is quite low. The transducers are able to couple directly through paint, thin layers of epoxy,or a small amount of general corrosion. However, if there is any flaking paint or corrosion, this shouldbe scraped or filed off. In addition, if there is any thick (greater than 1mm (40 thou)) coating, thisneeds to be removed from the portion of the pipe where the transducer ring will be mounted, which isapproximately 300 mm (1 foot) long.

In order to inspect the pipes that are insulated, the insulation must be removed over a small area, whichis typically one meter long. The areas where the insulation should be removed is usually marked on thepipe by GUL operators at a (pre-inspection) site visit. The transducer rings must be able to contactthe pipe wall around the entire circumference of the pipe. Therefore, any heat tracing or wire that isattached to the pipe should be released, leaving a minimum of 200mm (8 inches) between the pipe walland the wire. See figure 1.2 for a diagram of the required clearance.

In order to test pipes that are buried (for example cased road crossings), access to the bare pipe wall will



1.3 How the test is performed 4

be needed at several locations. How many locations to expose and where these locations are is typicallydecided as part of a risk based analysis program.

1.3.3 Dead zone

There is a small area (typically 0.5 meters (18 inches) long) on either side of the transducer ring that isnot inspected during the tests. In order to obtain complete coverage of the pipe, a test from a secondlocation (which overlaps the previous test position) must be performed. Alternatively, a complementarynon-destructive inspection technique can be used to inspect this area for defects.

1.3.4 Configuration of test parameters

The Wavemaker R©system allows for a wide variety of test parameters to be adjusted. These adjustmentsare designed to allow the operator to optimise the system depending on the local conditions. Some ofthe compromises that need to be made include:

• should the system try to inspect as close to the transducer rings as possible or as far as possible

• should the sensitivity be increased, which will reduce the distance that can be inspected in eachtest

• should the system try to minimize the influence of noise vibrations or try to maximize the axialresolution

1.3.5 Reproducibility of the test result

In general, the Wavemaker R© system is only sensitive to changes that occupy a significant portion of thecross section. This amount varies greatly depending on the pipe condition and can range from less thanone percent to 10 percent of the cross section. However, if an inspection result is compared to a previousresult at the same location, changes in cross section much smaller than this level (about 12 dB lower) canbe detected. In order to use the system to track suspected areas, the Wavemaker automatically saves thetests configuration as well as information about the identified features. The software also stores manuallyentered information (and/or GPS data) about the location where the test was performed. With thisinformation, current results can be compared to future ones to look for changes. The file size for eachtest position (which inspects many meters) is usually only a few megabytes, so the information can berelatively easily archived and provided to the plant operator. GUL offers the option for permanentlyattached rings that can be left on a pipe (and possibly reburied) in order to facilitate continued monitoringof a section of pipe with high sensitivity.

1.3.6 View of Processed Data

Typically, the processed results are presented as a trace that is similar to an A-scan, as shown in figure7.1 on page 66. The x axis is the distance away from the test position and the y-axis represents theamplitude of the reflection. At each change in cross section (or impedance) there is a reflection of theultrasonic energy that appears as a peak in the trace. In order to help the classification of the observedechoes, DAC curves are shown as dotted lines. In addition, there are two traces shown on the graph,one black and one red. The black trace represents echoes from features that are symmetric around thecircumference of the pipe (such as welds and flanges) and the red line represents echoes from non-axi-symmetric features such as corrosion and supports. The ratio of the red and black traces can be used toapproximate the circumferential extent of the observed feature. This information is used in conjunction



1.4 Formatting Conventions 5

with the Estimated Cross-Sectional Change (CSC) to classify the type of feature (and its severity if it iscorrosion).

The results can also be presented in several other formats, such as the estimated cross sectional areachange as a function of distance. If the wall loss in the areas identified have been measured and verified,the results can be also be shown as a function of wall loss versus distance.

Newer versions of the software can present the data in an ’unrolled pipe display’, that resembles a C-scan,showing the axial and circumferential position of any reflections.

1.3.7 Interpretation of the results

The interpretation of the results is the most difficult part of using guided ultrasonic waves to screenpipes. In order to evaluate the features that are present in the processed trace, various tools/techniquesare available to the operator of the system. Using these tools, a well-trained operator can classify thesource of observed reflections. However, this technique is a screening tool that can not be used to giveprecise ’sizing’ of defects or accurate estimations of remaining wall thickness.

The Wavemaker R©G3 Pipe Screening System is best used in conjunction with other techniques that canprovide a detailed measurement of the wall thickness over a localized area. The long range guided waveresults provide 100 percent coverage and identify the areas where corrosion exists. Time consuming andaccurate methods can then focus on this identified area to provide the exact wall loss information that isoften required.

1.4 Formatting Conventions

We use different formatting for various items throughout this manual.

Menus will look like Actions:Special. Actions is the main menu, Special is a sub menu.

Filenames will look like C:\WaveMkr\

Short-cuts to certain commands will look like F5

Display Screens will be referred to as ’Info:Stats’. On the Wavemaker R©G3 instrument, the first Itemrefers to the keypad button that must be pressed, the second button refers to the tab that shouldbe selected for that button. Keep pressing the keypad button until the correct tab appears.

Buttons in Wavemaker R© WaveProG3TM

or on the Wavemaker R©G3 instrument that always have thesame function will appear as ’Go’.

Soft Buttons that change actions depending on the text that appears beside them will appear as ”Lo-gon”.

1.5 Basic navigation - G3 instrument

Figure 1.3 shows a sketch of the front panel of the Wavemaker R©G3 instrument. The important controlfunctions are:

Keypad The twelve keys on the left are used to control the user interface on the instrument. Theirfunctions are described in later sections. By default, the keys have icons on them. However, this



1.5 Basic navigation - G3 instrument 6

ID Charge Host USB

A B C D

Transducer connections (A-D)

Digital InterfacesPower Check

Ring

Menu Stop

'Soft' buttons

Config

GPS Antenna

Info

Figure 1.3: Overview of the front panel of the Wavemaker R©G3.

document will refer to them as names such as ’Ring’. Figure 1.3 shows the position of some of theless obvious buttons.

Soft buttons/keys The three buttons with trianglar icons will be referred to as soft keys. The actionthat they cause is determined by the text that appears to the right of them on the screen.

Screen Displays output from the device. In order to save power, the screen will turn off if no keys havebeen pressed within the last few minutes. When in screen saver mode, the power light stays lit andthe Operator ID LED will flash. Press any key (except the ’Power’ key) to turn the screen backon.

GPS Antenna The antenna for the internal GPS is inside the box of the G3. In early G3s, the antennawas behind the plaque on the front panel. Newer versions have the antenna on the ’top’ of theinstrument above the keypad.

ID This round connection permits the reading of the operator ID keys. Simply hold the key againstthe reader (when the ’Logon’ screen is showing) until the display signals that it is complete. It isimportant that the iButton makes good contact with both the center of the reader and the edgefor a period of about 2 seconds. The green LED in the center of the ID button is used to indicateactivity when the screen is not on.

Charge The supplied 19 volt (100 Watt) charger should be attached to this connection to charge the in-strument or run from external power. This connection is also used for some advanced configurations(for example connecting two instruments together to record the transmitted wave amplitude).

Host This is a standard USB Host, such as the one that you find on the back of a PC. It is meantto provide a means of having external storage for data files that have been collected with theWavemaker R©G3. The host connection can also be used to attach certain external GPS units.Future software upgrades will expand the type of USB devices that are recognized.

USB This is the USB connection that goes to the PC. (See section 3.6.8.)

Transducer connections These are used to connect the Wavemaker R©G3 to the transducer rings.Please refer to section 3.7 for advice on how to properly handle these large cables).

All connectors are supplied with covers that should be screwed on when the connector is not in use. Thewill protect the electronics from moisture and dust ingress. However, please note that on early models(before G3-38), the ’Charge’ cap should not be in place when the instrument is shipped, since the chargesocket is used to equalize pressure inside and outside of the box.



Chapter 2

Initial Setup

2.1 System requirements

In order to use the Wavemaker R©G3 Pipe Screening System you will need a computer that is runningMicrosoft Windows R©2000 or XP and that contains at least one spare USB port. It is recommended thatthe computer has at least 512MB of RAM. (Please note that in most situations, the speed of executionof the WaveProG3 software is more limited by the available memory that a computer has than by thespeed of the processor.)

It is recommended that the computer is purchased in the region in which it will be used. Doing so usuallyfacilitates having the correct operating system for the local language, warranty repairs, and reducing totalsystem costs.

Our past experience has indicated that Panasonic Toughbook CF19 works well for data collection. (Seewww.toughbook.com for a list of suppliers.) This computer can be configured as either a notebook oras a tablet. It is relatively light, has good battery life, and is ruggedized. However, the screen and thekeyboard are relatively small. Therefore, many operators like to have a second (non-ruggedized, cheaper)notebook with a large screen onto which they download the results for final analysis and report writingin an office environment. An single computer alternative is the Panasonic Toughbook CF30. It has agood size screen and keypad, but is quite heavy.

2.2 Installing WaveProG3 software

WaveProG3 can be installed from either from the G3 itself, the original system CD or via the internet(if the G3 instrument is connected).

The first step in all of the installation procedures is to connect the the Wavemaker R©G3 to a spare USBport on the computer. After a few minutes the Wavemaker should appear as a disk drive on your computer(It uses class drivers that are built into the Windows operating system).

The installation routine (which can be seen in figure 2.1) is started using one of the three methods listedin the sub-sections below. The operation of the routine is very simple,

• The destination directory, which defaults to c:\WaveMkr, can be changed by clicking on the buttoninside the box marked ’Install Location’. However, we recommend that it is installed to the defaultdirectory to avoid filename paths getting too long.



2.2 Installing WaveProG3 software 8

Figure 2.1: The WaveProG3 installation dialog.

• The source for the installation is chosen from the choices on the left. The source (which is frequentlyautomatically chosen) will depend on the method that the routine was started.

• Clicking on OK starts the installation. The progress and any errors are shown in the bottomWindow. Both the application software and some supplementary drivers are installed. If Windowssays that a driver is not digitally signed, it is important that you click on the ’Continue Anyway’button. If cancel is pressed, the drivers that allow the iButton inspector operator keys to be readwill not be loaded.

• Clicking on Close exits the application.

Note 1. In order to install the software, the setup program must be run from a user account that hasAdministrator privileges.

Note 2. In order for the WavemakerR©G3 to be detected by the installation routine, it must appear asa drive letter D to M. If it appears as any other drive, then it will not be found. Therefore,please ensure that there are no other USB mass storage devices (such as USB keys) attachedto the computer when the WavemakerR©G3 is first connected.

Note 3. Windows 95 and Windows 98 do not support USB Mass Storage devices. Therefore, theWavemakerR©G3 will not be recognized when using these operating systems. The WaveProG3reader software can be used, but the full version will not work.

Note 4. The WaveProG3 software can safely co-exist with the WavePro software that is used tocontrol the previous generation of WavemakerR©SE16 instrument.

2.2.1 Installation from the G3

The core software can be installed directly from the Wavemaker R©G3 instrument. Once the G3 instrumenthas been recognized by the operating system and appears as a pair of disk drives, open the disk drivewith the lower letter (the drive should be called G3 on XP) and run the program called G3setup.exe.Choose the radio button marked ’Install WaveProG3 software from the Wavemaker G3’ and click on OK.

Note 1. Installing the software from the G3 only installs the core software. The help files, examplefiles, and logo files are not included and must be installed from a CD.

Note 2. Installing from the G3 will install the version of WaveProG3 that was current when theinstrument firmware was last updated. This version will frequently be out of date.



2.3 Running WaveProG3 without an instrument 9

2.2.2 Installation via CD

If installing from a CD, simply insert the CD. After a while, the setup routine should automatically run.If it does not, then run setup.exe in the root directory of the CD.

Choose the radio button marked ’Install WaveProG3 from CD Disk’ and press the OK button.

Please note that for the installation routine to work a Wavemaker R©G3 will need to be connectedto the computer and the current user will need to have Administrator privileges.

2.2.3 Installation via the Internet

If the original CD is not available, the WaveProG3 software can be installed on a computer that hasinternet access provided that the G3 instrument is also available and the Wavemaker R©G3 is still licencedfor upgrades. Although this is a longer procedure, it is frequently required in order to get the mostcurrent release of software.

1. Connect the Wavemaker R©G3, which should appear as a disk drive on the computer.

2. Run G3setup.exe which should appear in the root of the drive.

3. Select the button marked ’Download newest version from the internet’ and press ’OK’.

4. Wait for the (large) download to complete. This will create an ’upgrade file’ on your local computer.

5. Copy the downloaded file onto the computer on which you want to install the software and run it(or press the ”Run Now” button if you want to install the software onto the current computer).

6. Click on the ’Setup’ button to expand the archive and run the installation routine.

7. Select the ’Install WaveProG3 from CD/Disk’ button (which should already be selected) and pressOK.

2.3 Running WaveProG3 without an instrument

Typically, the WaveProG3 software looks for a Wavemaker R©G3 when it is started and the licence isextracted from the instrument itself.

However, for analyzing data, the WaveProG3 software can also be run using the licences in the iButtonsthat are used as the operator ID keys. The iButton looks like a watch battery and can be insertedinto a USB iButton reader (Maxim part DS9490B). The drivers for this reader should be installedalong with the Wavemaker R© WaveProG3

TMsoftware. Alternatively, they can be found on the web page

www.ibutton.com or on the installation CD that was supplied with the system.

If the iButton reader is connected and its drivers are correctly installed and your inspector ID keyis inserted, Wavemaker R© WaveProG3

TMshould run without the G3 instrument being attached. This

functionality is designed to allows previously collected data to be analyzed.

If the inspector ID key is not recognized, it is recommended that you

• Try unplugging and replugging the USB iButton reader and then restarting the software

• Ensure that the newest iButton drivers are correctly installed on your system (they can be down-loaded from www.ibutton.com).



2.4 Upgrades 10

2.4 Upgrades

2.4.1 Licence upgrade

On initial delivery, the Wavemaker R©G3 is normally loaded with a 50 working day pre-payment licence.After full payment has been received, a licence update will be sent (typically extending it perpetually).

This update can take two forms:

An iButton The iButtons are the same format as the operator ID keys and are described above. Se-lecting ’ID’ and ’Logon’ on the Wavemaker R©G3 and then holding the iButton to the ID connectorwill cause the internal licence to be updated.

A G3 key code A 30 digit key code may be sent by e-mail. In order to use this code, turn on theWavemaker R©G3 and run Wavemaker R© WaveProG3

TM(once the installation has been completed).

Choose the menu option Actions:Enter G3 Licence Key, enter in the 30 digit code that wassent, and press OK.

If the new licence code is accepted, the Wavemaker R©G3 will switch to the ’ID:Licence’ screen so thatthe updated licence can be viewed.

Note 1. The G3 key code is not case or space sensitive. It does not contain the letters ’O’, ’I’, or ’Z’,but can contain the digits ’0’, ’1’, or ’2’.

Note 2. The G3 key code can be pasted into the dialog by right clicking on the entry box and choosingpaste.

Note 3. If the key code was already on the clipboard when the menu option was chosen, the value isautomatically pasted and you only need to press OK to accept the value.

2.4.2 WaveProG3 upgrade

Upgrades of the Wavemaker R© WaveProG3TM

software will typically be released every 6 months. Eachsystem will be eligible for free upgrades for the first year after it has been purchased. After the first year,the system will only permit upgrades if the software upgrade package has been purchased from GUL.

The upgrades will be made available over the internet. In order to access them, simply follow theinstructions in section 2.2.3 for installing via the Internet. You may also request a CD be sent bye-mailing [email protected].

Note 1. When the WavemakerR© WaveProG3TM

software is upgraded, the previous version is renamedto WPG3-xxsx.exe, where xxxx is the date code of the build (in hexadecimal). Previous ver-sion can be run by double clicking on these files (which are typically in c:\WaveMkr\WavePro1directory.

Note 2. To get the build number and build date of the version of WavemakerR© WaveProG3TM

thatyou are running, chose the menu option Help:About.

The software built into the Wavemaker R©G3 instrument will also be upgraded using the same procedure.Specific instructions for upgrading the Wavemaker R©G3 are included with the upgrade CD. It is recom-mended that these firmware upgrades are performed by a GUL technician who has been trained on whatto do if the upgrade fails and the instrument is left in an unusable state.



Chapter 3

Preparing for a Job

3.1 Assessing the job

There are many items that should be assessed before an inspection is planned. Several questions shouldbe asked to ensure that the proper equipment is available and that there are realistic expectations ofwhat results can be provided. A list of example questions and the implications of these questions arepresented in table 3.1; further explanations can be found in later sections of this manual.

3.2 Frequency regime

Because of the nature of the waves that propagate in a pipe, the behavior of the guided waves varieswith the pipe dimensions. In order to normalize this effect, we tend to refer to frequency regimes insteadof actual frequencies of operation. The frequency regime is a logarithmic (dB) scale (a change of 6represents a doubling of the true frequency). Standard (Level 1) testing is performed in the positivefrequency regime. The interpretation of low frequency (negative frequency regime) results can be muchmore complicated and requires additional training.



3.2 Frequency regime 12

Table 3.1: Example questions to ask during a pipe survey.Question See ReasonWhat are the pipe diam-eters

3.3 Are all required pipe rings available? Does the pipe diametermatch one of our standard pipe rings? Beware of German orRussian standards that do not match the American ones.

Pipe support system(welded axially or cir-cumferentially, clampedor simply supported)

3.2 It is easiest to test under simple supports using standard config-uration. When there are welded supports, higher frequency ringsmay be preferred. The dimensions of welded supports should beprovided.

What coatings are on theline (Bitumen, coal tar,epoxy, mineral wool) andwhat condition are theyin

3.4 The coating type, thickness and condition will all affect the re-sults. Bitumen-like coatings reduce the test range significantlyand will therefore require many more test locations. Fusion bondepoxy lines normally need to be tested using the Wavemaker R©G3(the SE16 usually provides poor results). When the pipe is in-sulated, access locations must be preplanned.

What deposits are in theline

3.4 Bitumen deposits or well adhered scale inside the pipe will affectthe results as strongly as bitumen coating on the outside of thepipe.

What clearance is avail-able around the line

4.4 Three inches (75mm) clearance is usually required around theline. This can include heat tracing.

At what temperature isthe line running

4.3.1 The maximum temperatures (covered under warranty) are 70Cfor inflatable rings and 120C for solid rings.

Is the pipe buried? E Access locations will need to be planned. Please note that inter-preting buried pipe results is considered an advanced techniqueand is only recommended for Level 2 operators.

Access requirements - What sort of safety gear will be required? Will it be easy toperform complementary follow up measurements? How muchtime needs to be scheduled for permits and accessing the site?

General level of corrosion 3.2,3.4 On heavily corroded pipes the guided wave results will normallyindicate that the entire section is corroded, however, they willnot be able to tell you what the maximum wall loss is so in-tensive follow-up may be necessary. If testing heavily corrodedpipes, lower frequencies may be chosen to ’ignore’ smaller de-fects. Certain lines can be so heavily corroded that the screeninginspection is not commercially effective.

Expected defect type 3.3 Axial defects such as erosion require lower frequencies than cor-rosion type defects. Small pin holes are more difficult to detectthan patches of corrosion and will require a tighter spacing oftest positions.

What is the layout 4.1 Flanges, T’s and bends will strongly control where test positionswill be located.

What reporting require-ments are there

8 The level of reporting will significantly affect the total time re-quired for a job.

Drawings Line drawings provide an easy way to keep track of test locations.History Any history of previous corrosion on the line can be beneficial

for choosing test parameters.



3.3 Selection of transducer rings 13

As the frequency regime is changed, there are several effects on the guided waves. Some of these changesare illustrated in figure 3.1. They include:

Sensitivity changes For most types of defects, the higher the frequency regime the more sensitive thetest is to small defects. The defects in the corroded section (starting at feature +F4) of figure 3.1(a)are more visible at the higher frequency regime. However, the lower frequencies are often better atdetecting the worse areas in a generally corroded pipe.

Range changes Because lower frequency regimes are less sensitive to small defects, they tend to propa-gate further through corroded or attenuating pipes. The flange echo in figure 3.1 grows much largeras the frequency regime decreases.

Changes in the guided wave modes When the frequency regime becomes negative, the ’red’ trace,which is typically used to help judge the severity of defects is no longer an accurate measure ofthe circumferential extent (and therefore changes color to yellow). This effect can be easily seen inreflection from the +F1 defect in figure 3.1.

Differences in support reflections Although not shown in figure 3.1, the higher the frequency regime,the easier it is to test through clamped or welded supports.

Because of the strong effect that the frequency regime has on the performance of the system, the selectionof rings is quite important.

3.3 Selection of transducer rings

Depending on the requirements of any given inspection, the optimum style of ring may be different. Thereasoning behind choosing different types of rings is considered a level 2 skill. This document gives somegeneral guidelines for some simple cases in table 3.2. Please consult application specific procedures, yourown level 2 operator, or GUL support for suggestions on more esoteric cases.

Level 1 operators can use a variety of different styles of rings. The different rings styles are designed tocover different frequency regimes (that were discussed in section 3.2).

3.3.1 Solid Rings

The transducer rings are classified as either Solid rings (typically used for the smaller diameters) orInflatable rings (typically used for the larger diameters).

The overall design of the solid rings can be seen in figure 3.2. These rings are typically used for pipesbetween two and six inches in diameter. Six and eight inch diameter rings are made in both solid andinflatable styles. Typically, the solid rings work better for in-plant work (where there is a lot of acousticnoise and the features are closely spaced), but the inflatable rings are less expensive, can be adapted tooperate over a wider range of frequency regimes, and require less clearance around the pipe.

The solid rings come in two different width configurations, 18 and 24mm. The frequency regime ranges foreach size are given below in table 3.3. The outer diameters (and schedule 10, 40, and 160 wall thicknesses)that the rings are designed to accommodate are given in tables 3.3 and 3.5. In general, the solid ringscan inspect pipes that are 2mm larger in radius (usually due to coatings) or 3-4 mm smaller in radiusthan the stated design size. There is usually no difficulty using the same ring to test from schedule 10 toschedule 160 pipe. Contact GUL for advice on very thin or very thick pipes. For certain unusual pipesizes, such as 5 inches, GUL has special transducers that can be rented to adapt a conventional ring sizeto a slightly smaller diameter.




-5.0-5.0 0.00.0 5.05.0 10.010.0 15.015.00.00.0

0.50.5

1.01.0

1.51.5

2.02.0

2.52.5

Distance (m)Distance (m)

Amp (mV)Am

p (m

V)+F2+F

2+F1+F1 +F3+F3 +F4+F4 +F5+F5 FlangeFl

ange

-F1-F1-F2-F2-F3-F3

-5.0-5.0 0.00.0 5.05.0 10.010.0 15.015.00.00.0

2.02.0

4.04.0

6.06.0

8.08.0


Amp (mV)Am

p (m

V)

+F2+F2+F1+F1 +F3+F3 +F4+F4 +F5+F5 FlangeFl

ange

-F1-F1-F2-F2-F3-F3

-5.0-5.0 0.00.0 5.05.0 10.010.0 15.015.00.00.0

5.05.0

10.010.0

15.015.0


Amp (mV)Am

p (m

V)

+F2+F2+F1+F1 +F3+F3 +F4+F4 +F5+F5 FlangeFl

ange

-F1-F1-F2-F2-F3-F3

a) Frequency regime = +3.0

b) Frequency regime = 0.0

c) Frequency regime = -3.0

Figure 3.1: Changing the frequency regime of the test can have a dramatic effect. The results from thesame position on a pipe loop at a frequency regime of (a) +3.0, (b) 0.0, and (c) -3.0 are shown. The sizeof reflections and attenuation in the generally corroded section change dramatically.




Transducerelement

Hinge screw

Figure 3.2: (a) and (b) show two views of a solid ring; (c) schematic diagram of transducer elementsloading mechanism. Please note the orientation angles on view (b) that correspond to the positions inthe unrolled pipe display.




Table 3.2: Recommended frequency regimes for various application areas. The regimes are labeled aslow(< 0), standard(0-6), high(6-12), and v.high(> 12).Application Frequency

RegimeNotes

Generic pipe Stnd-High This is the defaultWelded supports HighTesting under supports on clean pipe HighTypical pipe rack Stnd-HighCUI Stnd-HighNeed to minimize dead zone (Very)HighGenerally corroded pipe Stnd-LowErosion or Axial defects Low-Stnd Requires special training module (part

of level 2 training)Concrete lined Pipe Low-Stnd Requires special training module (part

of level 2 training)Sleeved road crossing Stnd-High Requires special training module (part

of level 2 training)Road crossing soil-interfaces Stnd-High Requires special training module (part

of level 2 training)Buried Road crossing sections Stnd-Low Requires special training module (part

of level 2 training)Continuously buried pipe All Requires special training module (part

of level 2 training)

Table 3.3: The design dimensions and frequency regimes of various configurations of solid transducerrings.Style OD(in(mm)) Schd

10/40/160Wall(mm)

Width18

Regime

Width 24Regime

Notes

2 Inch 2.375” (60.3) 2.77/3.91/8.74 -6 to 2 -8 to -1 Size 18 recommended3 Inch 3.5” (88.9) 3.05/5.49/11.13 -2 to 5 -5 to +3 Size 24 recommended4 Inch 4.5” (114.3) 3.05/6.02/13.49 N/A -3 to +5 Only 24 available6 Inch 6.625” (168.3) 3.4/7.11/18.26 N/A +0.5 to +8 Only 24 available8 Inch 8.625” (219.1) 3.76/8.18/23.01 N/A +3 to +10 Only 24 available

From mid-2007 onwards, most solid rings are produced in an EFC variety. EFC stands for ’EnhancedFocussing and Circumferential resolution’. Using this variety improves the signal to noise and sizingcapabilities of the unrolled pipe display. However, this variety creates larger file sizes and cannot be usedwith the older SE16 electronics.

3.3.2 Inflatable Rings

The inflatable rings have been designed to provide a light weight method of testing large diameter pipes.As shown in figure 3.3, the inflatable rings themselves contain the required wiring and electronics for agiven pipe size. ’Modules’, which can be moved from one ring to another, are attached to the ring fortesting. Inflatable rings are produced to test pipes between 6 and 36 inches in diameter. It is possibleto test large pipes (26-110 inches in diameter) by combining multiple rings together. Combining ringstogether is discussed is section 4.4.3.

Different types and configurations of modules can be used to adjust the frequency regime of testing.There are two standard types of modules that are listed in table 3.4. Please note that the two types ofmodules should not be mixed together even when they are configured for the same width.




Positive direction

Curved arms

Clamping screws

Lemo housing

Inflate to 1.5 Bar(2.6 Bar (35 psi) max)

0o

180o

270o

90o

Figure 3.3: A schematic diagram of how the inflatable transducers rings are used. The angle orientationsrepresent the angles displayed on the unrolled pipe display. The positive direction is defined as towardsthe right when the clamp is on the side of the pipe towards you and the filler valve and connector housingare on the top half of the pipe.

Table 3.4: Types of modules used in inflatable rings.Name Width

ConfigurationsNotes

Standard Modules 20, 35 (Dft) These are used for the majority of applications. Itis relatively time consuming to change between thetwo configurations.

Wide bandwidth, variablespacing modules

20,35,50,70 These modules are designed to handle all situationsthat a Level 2 operator will likely be presented with.They have been designed to simplify changing widthconfigurations.



3.4 Test ranges 18

Table 3.5: The frequency regimes for various module width configurations and various pipe diameters.(Please note that the 70 spacing is not recommended.)

Size(in) OD(mm) Schd 40Wall

Num.Mods.

20Regime

35Regime

50Regime

70Regime

6.625” 168.3mm 7.11mm 20 +2 to 10 -3 to +5 -6 to +2 -9 to -18.625” 219.1mm 8.18mm 24 +4 to 12 0 to +7 -3 to 4 -6 to +110.75” 273mm 9.27mm 24 +6 to 14 +1 to +9 -1 to 6 -5 to +312.75” 324mm 9.53mm 28 +8 to 16 +3 to 10 0 to 7 -3 to +514” 356mm 11.13mm 28 +9 to 16 +4 to 11 0 to 8 -2 to +516” 406mm 12.7mm 32 10 to 17 +5 to 12 +2 to +9 -1 to +618” 457mm 14.27mm 36 11 to 19 +6 to 13 +3 to 10 0 to +720” 508mm 15.09mm 40 12 to 19 +7 to 14 +4 to 11 0 to +824” 610mm 17.46mm 48 14 to 21 +8 to 16 +6 to 13 +2 to 1030” 762mm - 54 16 to 23 11 to 18 +8 to 15 +5 to 1236” 914mm 19.05mm 54 17 to 24 12 to 19 +9 to 16 +6 to 1648” 1219mm - - 20 to 27 15 to 22 12 to 19 +9 to 16

The frequency regimes for various module width configurations are given in table 3.5. The table also liststhe number of modules that will be required for each ring. It is always recommended that a few extramodules are packed when preparing for site since they are susceptible to damage.

Note 1. In general, it is beneficial to work in the high frequency regime (≥ 6) on quite large diameterpipes. By doing so, the sensitivity is increased. Smaller defects (as a proportion of the totalcross sectional area of the wall) generally need to be detected because a small percentage ofa large cross section is still a physically large defect. For example, a two percent loss of crosssection in a 36 inch diameter pipe corresponds to a 2 inch through-hole.

Note 2. Interpretation in the low frequency regime (≤ 0) varies significantly from standard inter-pretation. It should not be attempted without attending the special low frequency trainingmodule (that forms part of the level 2 training). For this reason, the software restricts certainwide width configurations for some operator levels.

Inflatable rings some in both standard and EFC styles. The EFC style is usually recommended for usewith the Wavemaker R©G3 and the standard style for compatibility with the SE16.

3.4 Test ranges

It is difficult to predict the range of a single guided wave test without having a very large amount ofinformation about the pipe. Frequently, an effective inspection range of test is not known until afterthe data has been collected. This is because local corrosion or deposits can dramatically reduce the testrange.

There is a very simple method of getting a quick (very rough) estimation of the expected propagationdistance. Tap the pipe with a metal object such as a key. If it rings with a clear high pitch, then theguided wave propagation distance should be large. If it is a highly damped, dull thud, the guided waveswill likely not travel very far. The effect that is absorbing the acoustic sound waves produced by tappingwill also absorb the guided waves that the Wavemaker R©G3 Pipe Screening System uses.

Levels of corrosion, deposits, embedding material, support conditions, and coating properties all affectthe range. Table 3.6 indicates some typical test ranges that have been experienced in the past for certaincases. However, they are only indicative.



3.5 Packing for the job 19

Table 3.6: Average lengths of pipes that can be inspected from one location (in either direction) inthe standard frequency regime. Associated average attenuations are also given for reference (assuming atypical 40 dB of usable scale with the Wavemaker R©G3).Condition Typical range Attenuation (dB/m)Straight line, simple support, little corrosion 50-200m 0.8-0.2Typical clean, 30 year old pipe 20-50m 2.0-0.8Typical generally corroded, 30 year old pipe 15-30m 2.6-1.3With factory applied foam 10-20m 4-2With thin, hard bitumen 5-25m 8-1.6With thick, soft bitumen 2-8m 20-5Grout lined pipe 10-30m 4-0.75Poorly adhered concrete wall 2-8m 20-5Well adhered concrete wall 1-2m 40-20

3.4.1 End of Test

It is important to recognize that the end of a guided wave test is usually not a distinct event. Fartheraway from the ring position, the signal to noise ratio deceases. It will eventually reach a point where therefection from the size of defect that must be found will be smaller than the noise floor. An inspectortypically declares the end of test as the point when the reflection from a defect of declared minimumsensitivity level would be twice as large as the noise floor (to give a 95% POD). However, large defectscan often be found after this declared end of test.

The geometry of the pipe being tested also enforces certain ends of diagnostic tests.

Flanges Not enough energy propagates through flanges for any meaningful analysis of the data after-wards. The usually happens for large welded annular rings.

Bends With additional processing, it is usually possible to work through one sharp bend. However, thesignal to noise is degraded. By the time that the signal has gone through two bends, it is usuallynot possible to detect many critical defect sizes, unless the bends are very gradual.

T Pieces It is usually possible to test through one T piece. However, the area of the actual T (and thelikely erosion location) as well as a short distance beyond the T will not be inspected. In addition,signal to noise ratio will be poorer in the section after the T. Therefore, when possible, avoid testingthrough T pieces. The section of the T that is perpendicular to the original propagation directioncannot be inspected.

Welded supports Depending on the and size size (in relation to the pipe size) of support and thefrequency regime of testing, welded supports can dramatically reduce test distances. In the worstcases, the pipe can realistically only be tested between the supports. In the best cases, there islittle effect.

3.5 Packing for the job

To increase the reliability of the system, there are several actions that should be taken before the beginningof each job (and ideally at the beginning of each day). These actions reinforce the automatic checks thatare made during each test and help ensure that no major systematic errors are introduced into the results(which may invalidate all of the data).

Note 1. Suggested maintenance regimes are listed in Chapter 9.

Note 2. The WavemakerR©G3 has much more sophisticated error checking than the previous gener-ation SE16, which should help reduce on-site failures.



3.6 Wavemaker G3 instrument 20

Note 3. Data should not be collected with equipment that is showing error warnings. The G3 in-strument will block analysis if serious errors are detected. If minor errors are detected, theinterpretation will be much more difficult.

Some suggested materials are listed in table 3.7. This can be used as a base for a packing list whenpreparing the equipment for a job. The checks that should be performed on each item can be found inthe later sections that are referred to in the table.

GUL packs the rental equipment into PeliTM

(or PelicanTM

) cases, which have proven durable and wa-tertight. Most of the equipment fits well into the 1620 case (that has integral wheels and handle). Themain disadvantage of these cases are their weight.

3.6 Wavemaker G3 instrument

When preparing for a job the Wavemaker R©G3 instrument can be checked to see if it functions correctlyand if the battery is fully charged. The following checks require that the operator is familiar withnavigating around the G3 user interface (described in section 1.5) and the layout of the front panel(shown in figure 1.3).

3.6.1 Charging

The Wavemaker G3 contains two internal Li-Ion batteries that are designed to provide enough power torun the instrument for over eight hours. The batteries should only be charged by attaching the supplied19VDC (100W) charger to the ’Charge’ connection of the front panel of the instrument. The batteriesshould only be charged when the temperature inside the case (which is reported on the ’Info:Stats’ screen- see figure 3.5(a)) is between 15C and 50C. In order to prolong the life of the batteries, it is best to onlycharge them when the instrument is between 20C and 35C.

When the batteries are being charged the ’Info’ button on the keypad will light green. The pattern offlashing will indicated the current state

• A long period on followed by a short period off indicates normal charging.

• A very fast flashing light indicates some sort of error. The ’Info’ screen on the instrument willprovide more detailed information about the error code. Please note that during a normal chargingcycle (slow blinking) there may be short (20 second) periods during which the light flashes quickly;this is normal behavior.

• When the batteries are fully charged, the green info light should turn off.

It is possible to both charge and run the Wavemaker R©G3 at the same time. This functionality is de-signed to allow data stored on the instrument to be downloaded or functional checks performed whilein an office that has a relatively clean mains power supply. For best signal to noise performance, it isnot recommended that either the Wavemaker R©G3 or the controlling laptop are run from invertors (forexample from a car cigarette lighter) while test data is being collected. Please disconnect them for theshort duration of the test.

The Wavemaker R©G3 must not be run directly from a car battery (as could be done with the earlierSE16). A separate car charger can be purchased from GUL to charge the Wavemaker R©G3 from yourcar. However, this charger should be disconnected during data collection and should not be used as anexternal power supply for running the instrument.




Table 3.7: A packing list of items that typically required on site.Item See section NotesWavemaker G3 3.6.1 The battery should be fully charged for the start

of each day of operation.Charger 3.6.1Ring cables 3.7 Typically, two cables will be required. At least

one spare is recommended.Rings 3.8 Check all ring diameters and ensure the correct

frequencies are chosen. Enough modules for thelargest inflatable along with a few spares mustbe packed.

USB Cables 3.6.8 A USB connection is required between the G3and the laptop

Laptop With charged spare batteriesBicycle pump The pump must have a pressure gaugeMeasuring tape 5m and 30m tapes are recommended4mm Allen key For adjusting the offsets of solid ringsPaint scrapper, file, and stiffwire brush

For cleaning the pipe

Notebook / pens / pencilMirror / flashlight Especially when testing sleeved road crossingsUT set For follow-up testing and checking nominal

thicknessCompass For documenting the positions from where the

test is conductedMulti-meter that can measurecapacitance with 0.1 nF accu-racy (optional)

3.8 Used to manually test rings

Spares / repair kit (Optional) Metric sized Allen keys and a Phillips headscrewdriver are very useful

Needle nose pliers 3.8 If switching transducer orientations or moduleswill be necessary

Pit gauge For measuring external wall lossPaint Marker For marking test location on the pipe (Tape can

also be used)Digital camera For documenting external corrosion (if allowed

on site)PPE Personal safety gear minimum requirements are

gloves, protective glasses, and protective boots(on top of requirements of the site where theequipment will be used).

Plastic sheeting To protect the equipment from heavy rainReflective sheeting To protect the equipment from direct sun in

desert environments.Tool belt or box (optional) To carry everything




For optimum battery life, it is recommended that the Li-Ion batteries are not allowed be discharged toofully, nor charged too frequently. It is recommended that they are recharged when they reach 40 percentfull (or 14 V) or when the instrument will be required to do a lot of work the next day. It is also best tocharge Li-Ion batteries in a cool environment.

Safety Note Only use the supplied charger indoors in a dry environment.

Safety Note Use a 3 pin plug (that contains a ground connection) with the charger in order to avoidstatic charge build up on the front panel of the instrument during charging.

Safety Note Do not charge the batteries if the internal temperature of the instrument is greater than50◦C. (Below 35◦C is recommended)

Safety Note Never expose the batteries to a naked flame or temperatures greater than 60◦C in order toavoid the risk of explosion.

Safety Note Never put the Li-Ion batteries in the trash. They must be disposed of properly.

Safety Note When charging using the standard charger, the WavemakerR©G3 is considered a Class I ap-pliance. An alternative Class II charger can be produced if required for a certain application.

3.6.2 Turning On

Pressing the power button in the top left corner of the keypad on the Wavemaker R©G3 instrument switchesthe instrument on. The button must be held down until the buzzer stops, which is normally about asecond. The initialization process takes a while because the instrument carries out several self checks;please be patient. When turning on, the following sequence can be expected. The ’LED’ column refersto the green LED that is marked as ID on the front panel.

Item LED NotesMemory tests On Initial tests take about 2 seconds (during which

time the instrument does not respond)Boot Loader Flashes This loads the main application. It should take

about 1 second. If the system enters a continuousloop of a quickly flashing LED then the applicationhas been corrupted and it must be sent back to theGUL for servicing.

Main App. Load On The main peripherals are initializedMain App. Start - After a few seconds the ELD screen will turn on

providing detailed information about what is hap-pening. If the screen does not come on within 10seconds, the cable has likely come loose or a fatalerror has occurred. Please refer to troubleshooting.

Logon Screen Flash The Wavemaker R©G3 expects an operator to logonat least once a day. If no one has logged on, thenthe logon screen appears (see section 3.6.4

Ready - If the instrument licence has not expired, then theinstrument is ready to use. Otherwise, a messagewill be displayed.

Note 1. Some early G3’s can be turned on by pressing any button on the keypad.

Note 2. The WavemakerR©G3 will refuse to turn on if the battery voltage is below 12.5V.

Note 3. After shipping the instrument, check to make sure that the instrument is sufficiently charged.If it is shipped with a sealing cap covering the ’Charge’ connection, early versions of theWavemakerR©G3 (before G3-38) can turn themselves on when the atmospheric pressure in-creases significantly.




Figure 3.4: The ’ID:Logon’ screen on the Wavemaker R©G3.

3.6.3 Turning Off

Once the initialization procedure has completed, the instrument can be turned off by simply pressing the’power’ button on the top left corner of the keypad.

In the unlikely event that pressing the ’power’ button does not turn off the instrument (or if theinstrument is still performing initialization), then press and hold the ’power’ button for 7 seconds. TheID LED will start to flash quickly and the buzzer will make short beeps. At this point, release the’power’ button and the instrument should turn off.

In the extremely unlikely event of a software corruption error, the procedures above will not work. Inthat case, the instrument will need to be sent back to GUL for repair. To turn it off, open the case,remove the electrical shielding plates, do not touch anything but the battery connectors, and disconnectthe batteries from the mainboard.

Note 1. The WavemakerR©G3 instrument will automatically switch itself off when the battery voltagereaches 12V. This is to protect the Li-Ion batteries.

Note 2. If no keys are pressed for a while, the screen will be turned off to conserve power. Pressingany key (other than the power key) will turn the screen back on.

Note 3. After a long period of no activity the WavemakerR©G3 will automatically turn itself off. Theperiod before it shuts down depends on whether it is running from battery or external powerand whether or not it is connected to a PC at the time.

3.6.4 Logging On

At the beginning of each day, the Wavemaker R©G3 requests that an operator logs on. The logged onoperator is used for various purposes, such as customizing logos, logging the tests for operator revalidation,and assigning the ’Tested by’ field in the report.

The ’Logon’ screen looks like the screen shot in figure 3.4. When this screen appears, simply attach youroperator ID button to the reader that is labeled ’ID’. It is important that good contact is made withboth the center and the edge of the socket. The information should be read and test log informationshould be updated in the button within a few seconds. The progress is shown on the left side of thescreen. If you wish to skip operator logon and thereby run in a mode that is non-compliant with theGUL operator training scheme, press any keypad button and the logon operation will be aborted.

If you wish to change operator mid-day, or ’credit’ your operator key with the tests you have performedit is possible to access the logon by going to the ’ID:Operator’ and pressing the ”Logon” button. Thisoperation should be performed whenever you will be changing which G3 you are using; failure to do sowill mean that the test days and count displayed when you log on are not updated correctly.

Choosing the ”Logoff” button causes the Wavemaker R©G3 to forget which operator is logged onto theinstrument and asks for a new operator to logon whenever the instrument is next turned on.




a) b)

Figure 3.5: The (a) ’Info:Stats’ and (b) ’Info:Versions’ screens on the Wavemaker R©G3.

3.6.5 Basic Checks

When the Wavemaker R©G3 instrument is powered up, it runs through a series of basic checks, theseinclude checking the basic digital circuits of the main component boards. If there is a failure of one ofthese items a large message will appear on the screen and the instrument will turn off automatically aftera few seconds. In these situations, the unit must be sent back to GUL for repair.

The results of the test (and the relative versions of the boards and accompanying software) can be seen bypressing the ’Info’ button on the keypad. The first screen (see figure 3.5(a)) shows general informationand the second tab (see figure 3.5(b)) lists the versions of the various cards in the instrument. Thisinformation is used in the troubleshooting routines; it includes individual serial numbers for each of theboards as well as revision and production date information.

The analog section of the boards can be tested by selecting the ’Check:Cards’ screen and pressing the”Card Check” or ”Full Check” button. This test should be started when there are no cables connectedto the Wavemaker R©G3. An example plot of the results appears in figure 3.6. Two values are checked:

Phase The top graph shows the phase variation between the channels. In the example shown in figure3.6, all of the channels have the same phase (within 0.5 percent). The maximum permitted variationis 5 percent; variations typically are caused by slight differences in the components (which may varyover time and temperature).

Amplitude The bottom plot shows the amplitude variation between the channels. The software isable to automatically compensate for amplitude variations. Therefore, the maximum permitteddeviation should be 25 percent.

The ”Card Check” option is quite fast and only checks the most commonly used components on theboard. The ”Full Check” option takes much longer. However, it checks all of the filter and gain settingcombinations, it is should be able to detect the failure of even a single component.

In general, if there is only one channel that is showing problems, it is possible to select connector optionscarefully to avoid this channel. Connectors A and B are routed to the channels that appear on the firsthalf of the display; connectors C and D appear on the second half of the display. By avoiding a singlebad channel, it should be possible to complete the rest of the tests for that day. However, the instrumentshould be sent back to GUL for repair as soon as practical. If multiple channels are showing errors,the instrument usually cannot be used to collect data until it has been repaired. (The Wavemaker R©

WaveProG3TM

software automatically blocks analysis of data that it thinks is corrupted.)

3.6.6 Open Box Checks

Significant effort has been placed into preventing the need for the box to be opened. However, there area few cases that may require inspection of the internal connections. First, the desiccant may need tobe examined (see the next section for details). Second, if any of the faults below are encountered, the




Figure 3.6: The ’Check:Cards’ screen on the Wavemaker R©G3.

instrument should be checked for any loose connections. This may require removing the shielding plates.Symptoms of this type of fault include:

• The instrument does not turn on when a keypad button is pressed;

• The screen does not come on or it flashes wide vertical bars;

• The USB device or USB host do not connect;

• The same channels always fail card checks (see section 3.6.5) or the cable checks (see section 3.7);

• The ID LED does not turn on;

• A loose screw or nut can be heard moving around in the box when the instrument is tilted (gently)in different directions.

Safety Note When the G3 is running, high voltages can be present on the back of the ELD screen as wellas on the side of the main-board that is marked with the high voltage warning triangle.

3.6.7 Desiccant Checks

If a silicone desiccant has been placed within the instrument (because it is destined for a humid environ-ment), it should be checked every month to ensure that it has not saturated with moisture. The desiccantwill likely need to be replaced every 6 to 12 months.

On early instruments (before G3-35), 30g silicone desiccant containers are attached to the internal bodywork. These holders have indicators that start out blue (when they are dry) and turn pink (when theyare saturated). They can be reactivated by removing them from the G3, placing in a ventilated ovenat 125◦C (250◦F) for 4 hours and then cooling in a sealed container. See figure 3.7 for the location of thecontainer. Alternatively, a new desiccant canister can be inserted.

More recent instruments use a 100g desiccant bag that is attached to the inside of the top metal workcover. A humidity indicating strip should be present on the outside of the metal work (but inside theblack plastic outer case). When it is indicating greater than 40% humidity, the desiccant should bereplaced. To do so:

• Remove the 8 M4x16mm screws from the front panel (#2 Posidrive). Ensure that the red fibrewashers are not lost.

• Pull the G3 out from its outer case

• Remove the numerous M3 screws (with integral lock washers) from the top metal work cover (theside with the GPS antenna) using an #1 Posidrive screwdriver.

• Flip the cover over and remove the 4 M3 nuts (5.5mm A/F) that are holding the desiccant bracketin place.

• Replace the desiccant and reassemble.




Figure 3.7: The position of the desiccant container within the Wavemaker R©G3 box.

3.6.8 USB Cable

The USB cable between the instrument and the laptop can be checked by simply connecting the devicestogether (with both devices on) and seeing if the Wavemaker R©G3 is correctly connected as a disk drive.A file such as status.txt can be opened on the Wavemaker R©G3. Moving the cable around should notcause the disk drive to disappear or the connection signal in the status bar of the Wavemaker R©G3 tochange.

Note 1. Only one copy of WavemakerR© WaveProG3TM

can access the instrument at one time. Ifadditional copies are opened, they will not be able to control the instrument.

Note 2. While WavemakerR© WaveProG3TM

is running, it will not be possible to access the device

as a disk drive. WindowsTM

will report an ”Access denied” error.

If the USB cable has a fault, a standard USB A-B cable that can be purchased in any computer storecan be used. Please contact GUL or a Bulgin Connector distributor to obtain a cable with an integralseal that was supplied with the instrument.

Under no circumstances should the cable be ’extended’ by cutting it and splicing in another 5 meter cable.If more than five meters (15 feet) distance is required between the Wavemaker R©G3 and the laptop, thenpurchase an (inexpensive) active extension cable that is available from many computer suppliers. Upto 5 active extension cables can be combined together to obtain a total range of 30 meters (90 feet).If more than 30 meters is required, it is recommended that you simply allow the instrument to collecton its own (see section 5.4) and download the data later. Alternatively, GUL can provide an RS485adaptor box that allows control of the instrument from up to 1000m. However, collection via this linktakes significantly longer.

The USB connections on the instrument and the laptop may wear out after a few years of use. Keeping theconnectors clean helps prevent this from happening too quickly. The connection on the front panel of theWavemaker R©G3 has been designed for easy replacement and can be changed during periodic servicing.



3.7 Ring cable checks 27

a) Correct insertion carefully aligns the connectors and avoids twisting the connection between the cableand the connector.

b) Correct removal only pulls on the knurled sleeve, not on the cable.

Figure 3.8: Correct a) insertion and b) removal techniques for the main ring cables.

3.7 Ring cable checks

The 8 channel ring cables are the most likely element of the system to be damaged. Most of the problemsare caused by twisting the connectors relative to the cable, pulling on the cables, or stepping on thecables. Careful handling of the connectors can avoid most of these problems.

When connecting or disconnecting the transducer cable from the transducer ring or the electronics, alwayspull squarely gripping the knurled sleeve of the plug as shown in figure 3.8. It can be difficult to removenew cables from new instruments or rings. If this happens, try pushing the cable in as far as possiblewhile pulling back on the knurled portion of the connector. This operation causes the sprung retainingfingers to be retracted as far as possible.

The connectors on the ends of the cables should be regularly inspected for damage.

Item NotesPins All of the pins should be straight and gold colored. They should all pro-

trude by about the same amount.Clean The inside of the connector must be free of dirt or grit. Clean with com-

pressed air or speciality solvents (the material is PEEK).Nicks Check to make sure that there are no large dents or nicks on the end of

the connector. Any damage in this location makes the cables very difficultto insert or remove.

Roundness The ends of the connectors should always be round.



3.7 Ring cable checks 28

ID Charge Host USB

A B C D

For the cable check, loop the cable from A connector to the C connectorCheck

Figure 3.9: How the cable should be connected to perform a cable check.

Figure 3.10: The ’Check:Cables’ screen on the Wavemaker R©G3. In this case, there is a major problemwith channel 3 of the cable.

Any electrical faults with the cable can have very serious affects on the results. The most commonappearance is a major degradation of signal to noise. The faults can usually be easily seen as a corruptionof the raw data pulse-echo traces.

The best way to check a cable is to connect a fully populated ring and perform the ring checks describedin section 3.8. However, it is also possible to test the continuity of some of the connections on thecable using just the Wavemaker R©G3. To engage the test method, select the ’Check:Cables’ screen onthe Wavemaker R©G3 instrument. Then insert one side of the cable into the A connector and one intothe C connector, as shown in figure 3.9. Press the soft button ”Check”. The instrument will sendan attenuated signal down each of the eight channels. The result will look like figure 3.10, where eachbar represents a transducer channel. If there is an open channel or a short of the center of the coaxialconnection, the corresponding bar on the graph will be affected. It is recommended that the test isrepeated several times with the cable being gently bent in different directions. This will help pick upsome problems that appear as intermittent. However, it will not pick up problems with the shield of thecoaxial connections.

Note 1. The built in cable check is not capable of detecting a problem with the logic lines that areused to detect and uniquely identify a ring. In addition, faults that affect only the shieldcan be missed with this check. However, these two items will be checked along with the ringitself in section 3.8.

Note 2. Repairing the cables (especially the old style) requires some special tools and quite a bit ofpractice. GUL discourages field repairs and recommends that any damaged cables are sentback to us for repair

Note 3. One common problem with the cables is that one of the pins gets pushed back into theconnector body (usually because the socket on a ring is something in it). This problem canbe seen by looking into the end of the cable. All 24 pins should protrude the same amount.



3.8 Transducer rings 29

Table 3.8: Physical checks to perform on Solid rings (see figure 3.2 for location information).Item NotesThe hand knobs on the rings The large M10 hand knobs should turn easily. Check that the

threads are not damagedCondition of load plates The hand knobs should bear down on stainless plates. Ensure

that these are present and in good order.M5 adjustment capscrews All of the M5 transducer height capscrews should turn easily

when the ring is on a pipe. If they do not, then they arescrewed in too far, they need to be greased, or the transduceris not oriented correctly.

M6 Hinge Bolts The bolts holding the hinge arms in place tend to loosen overtime. Ensure that these are (at least) finger tight.

24 Pin Lemo R© connector The socket for the 24 pin Lemo R© connector should be firmlyanchored in its housing. It should not be able to spin or pullout. It should be free of debris.

Transducer elements All of the transducer elements should be present. If any fallout during shipping, please ensure that they are replaced inthe correct orientation. One of the two small holes in the topof the transducer should align with a pin on the transducerload block. (When shipping the rings, cover them in cling filmor stuff the inside of the ring to prevent the transducers fromfalling out.)

Transducer alignment All of the transducer elements should be facing the same way.In almost all cases, this should be around the circumferenceof the pipe (as indicated in figure 3.2).

If one is farther back then all of the others, then it will need to be pushed back into placeby disassembling the connector and using an appropriate tool to reposition the pin.

3.8 Transducer rings

The transducer rings can develop several problems that would cause serious errors in the results. There-fore, there are several things that should be checked. These items include both physical and electricalchecks.

3.8.1 Physical checks

Table 3.8 lists what checks should be performed on the physical condition of the solid rings before packingfor site. Similarly, table 3.9 lists the checks for an inflatable ring.

If inflatable rings are going to be used on site, it is recommended that at least the first size of ring thatwill be used is fully populated with modules before packing for site so that the electrical checks describedin section 3.8.2 can be performed. In addition, it is much easier to pack the modules when they areattached to a ring.

The process of attaching modules to an inflatable ring can be described in the following steps (which arealso outlined in figure 3.11):

• Inspect the module to be attached. Both transducer elements should be present and undamaged.Check the right angle MCX connectors that are embedded in the module to ensure that they areintact and straight.




Table 3.9: Physical checks to be performed on an inflatable ring (please refer to figure 3.3 for a diagramshowing the layout of an inflatable ring).Item NotesClamping screws The M5 (or M8 depending on rings style) clamp screws should

turn freely. If they have been bent, they will need to be re-placed. It is always recommended that the knobs are fullyscrewed down when the rings are packed in order to avoidbending them.

M3 Clamp locks The four M3 screws holding each curved clamp arm should befully tight. (Non-EFC rings only)

MCX Connectors All of the MCX connectors in the module pins should bepresent and clean. (See figure 3.11 for their location.) Pleasebe aware that a damaged pin here can damage modules, whichcould then damage other ring pins.

24 Pin Lemo connector(s) The socket for the 24 pin lemo connector should be firmlyanchored in its housing. It should not be able to spin or pullout. It should be free of debris.

Clamp operation It should be relatively easy to insert and detach the clamp.Modules All of the modules should be of the same type and set at the

same spacing.

• Check width configuration. Ensure that the width configuration is the width that has been selectedfor the next test and that it matches the other modules. The width can be changed by removing thewidth locking U-pins (see figure 3.11), sliding the transducers to the correct position and replacingthe U-pins. The width configuration numbers represent the spacing (in mm) between the center ofthe two face plates.

• Pull the retaining U-pins (the ones half way up the modules) out from the side of the module farenough so that they are no longer blocking the pin locating hole in the module.

• Check the pins on the ring. The pins on the inflatable ring (and the MCX sockets within them)should be intact and clean. The M10 fine half nuts holding the pins to the bag should be at leastfinger tight.

• Place the module over the pins on the inflatable and squeeze gently until the module sits correctly.

• Insert the U-pins until they sit correctly. The U-pins can be stiff when the modules are new, butthey should become easier over time. Do not force the U-pins in. If too much force is required itusually means that the MCX connector in the module is misaligned or the M10 fine half nut is notfully tight.

• If the U-pins are loose and fall out easily, remove the offending pin, spread its legs slightly using apair of pliers and reinsert it.

3.8.2 Electrical checks

The rings are designed to house an array of individual transducer elements. The presence and correctoperation of the vast majority of these elements is required in order to maximize the signal to noise ratioof the processed results. There are several levels to these checks.

Ring identification

Each ring has simple electronics buried into it to allow the software to recognize it and configure thecollection correctly. If there is a cable or ring fault, this information can be lost and a test will not be




M10 half nuts must be fully tight

Width locking Pins

Retaining U-pinsOrientation Marker

MCX connector (on ring)

Figure 3.11: Schematic diagram of how the modules are fitted onto an inflatable ring.




Figure 3.12: The ’Ring:Ring ID’ screen on the Wavemaker R©G3.

Figure 3.13: The ’Ring:Impedance’ screen on the Wavemaker R©G3.

able to be performed.

To test to make sure that a ring can be identified, turn on the Wavemaker R©G3 and go to the ’Ring:RingID’ screen shown in figure 3.12. Connect the ring to any of the front panel connectors and after a fewseconds the ring definition code should appear in the correct connector line. If it does not appear, youcan try:

• Pressing the ”Read Rings” or ”Force Redetect” button to force the instrument to re-read thering.

• Using different cables.

• Cooling the ring down (so that it is less than 60C).

• Send the ring (and the cable) back to GUL for investigation and repair.

The displayed ring ID (and pipe size) should match those on the brass plaque that is mounted on therings. Rings with two Lemo connectors should appear twice (once for each connector). The ’primary’connector will show the actual ring code (usually starting R2B or R2F); the ’companion’ connector willhave the same serial number, but the ring code will show up as ’R2C’.

Capacitance

The primary check of the transducer elements involves an impedance (capacitance) check of a wholegroup of transducer elements to detect if there is a problem affecting the entire group. These tests will beautomatically repeated every time that a test is performed. If any major errors are detected, the analysisof data will be blocked. Therefore, it is important to check the rings before leaving for site so that thereis enough time to repair any problems.

The easiest way to perform this check is to connect the ring to the Wavemaker R©G3 instrument. Go tothe ’Ring:Impedance’ screen and click on the ”Check Z” button. After about 10 seconds, a bar graphshould appear showing the received capacitance for each of the channels of the ring. These should all beroughly the same. Warnings are given if values are out of certain bounds. An example of the output fora correctly functioning ring is shown in figure 3.13.




CH 1

CH 2

CH 3

CH 4

CH 5

CH 6

CH 7

CH 8

Figure 3.14: Relationship between the pins in the 24 pin Lemo R© connectors (as view from the outside)and the segments to which they direct signals.

Note 1. The values that the instrument reports for the capacitance will likely be different from thevalues reported by a multi-meter because the two types of instruments use different methodsto measure the capacitance.

Note 2. We typically expect that capacitance will be about 1 nF for each transducer that is connectedto the segment (plus a little more for the cable).

If a problem is detected with the capacitance, it is usually best to repeat the measurement with a differentcable. If the problem persists, use the wiring layout diagrams in figure 3.14 to determine which sectionof the ring is affected. Individual modules (or transducers) within that segment can be replaced andthe capacitance check repeated until the problem hopefully disappears. If a bad module (or transducerelement) is found, please clearly mark it as defective. Wrapping the connector in tape usually proveseffective. Failures in the internal wiring of the ring can also strongly affect the capacitance of a wholesegment. These errors can be intermittent (for example only appearing when a ring is clamped or inflatedonto a pipe). These sort of errors must be repaired by sending the ring back to GUL.

It is also possible to test the capacitance of the channels using a standard multi-meter. It is recommendedthat a capacitance meter with at least 20 pF resolution is used. In order to check the capacitance of asegment, attach the meter across the two pins that correspond to the shield and conductor of the segment.Figure 3.14 shows how the pins in the 24 pin Lemo R© connectors relate to the various segments in thering.

Each transducer should contribute about 1 nF of capacitance to the segment. All segments should bewithin 1 nF of each other. Therefore, if you are testing a 6 inch ring that has 5 transducers per quadrant(a total of 20 transducers around the circumference), the capacitance should measure between 4.5 and5.5 nF (nano-Farads). Various error conditions include:

• Zero capacitance indicates an electrical short circuit. This could be caused by pinched wires in thering or by a transducer that has failed.

• Very low capacitance (� 1 nF) usually indicates an open circuit. This usually happens because ofbroken wiring in the ring cables.

• A capacitance of one nF below the expected value indicates that one transducer has failed. All ofthe transducers in the given segment should be removed and checked individually.

• Very high capacitance usually indicates a failed transducer. All of the transducers in the givensegment should be removed and checked individually. If a faulty transducer is found, it should bereplaced.




Figure 3.15: The ’Ring:Coupling’ screen on the Wavemaker R©G3 when an individual transducer is beingrubbed.

Transducer element function

Each of the transducer elements should first be visually inspected. The white faceplate should not becracked. It should be centered in the transducer body. There should be no signs of corrosion product onthe transducer.

With the Wavemaker R©G3 instrument, it is possible to quickly perform a functional check of each of thetransducer elements. It is recommended that this operation is performed whenever there is a variation inthe capacitance of a segment, an inflatable ring has been populated, a big job is about to start, or everyweek of usage. To perform the function check, do the following:

• Connect the ring to the Wavemaker R©G3.

• Go to the ’Ring:Coupling’ screen on the instrument. A schematic drawing of the ring (as shownin figure 3.15) should appear if the ring is a standard design. Each labeled square represents onesegment with the labels indicating the connector channel that it is mapped to.

• Adjust the gain up and down using the soft buttons so that the noise level can just be seen on thesquares. A gain level of 70 dB usually works well.

• Rub the transducer along the length of the white faceplate. The corresponding square (representingthe channel that the transducer is connected to) should rise. In the example shown in figure 3.15,the channel connected to ’A5’ is being rubbed.

• Repeat the last step for each of the transducers in the ring. Any transducers which do not have anoutput should be replaced.

Note 1. The ’Ring:Coupling’ screen drains the batteries very quickly. If many rings are going to betested, then it is recommended that you run this test with the WavemakerR©G3 poweredfrom its AC adaptor.

Note 2. If the battery is low, the updating of the noise bars may be slower than usual.

Note 3. Ensure that all of the transducers appear on the correct side of the ring. The wiring inthe module is crossed over; if a transducer in a module had been replaced and put in theincorrect position, it will very strongly degrade the results.

Note 4. It is possible to test the wiring of an unpopulated inflatable rings by touching one end of ashort un-insulated length of wire to the center of the MCX connector in the pins and holdingthe other end of the wire in your hand. (Holding the wire injects noise into the channel whichis picked up the by instrument.) However, please note that when an unpopulated inflatablering is tested in this manner, the forward and backward rows will be swapped in comparisonto how they appear on the display. This swap appears because the wiring in the modules iscrossed over.



Chapter 4

Preparing Location

Once the initial checks of the equipment have verified its fitness for operation (see sections 3.6, 3.7, and3.8) and permits have been arranged, the following steps can be taken to prepare the test location andattach the transducer ring.

4.1 Select test location

Test locations should be chosen in order to minimize the number of non-symmetric features (such as bends)that need to be traversed by the ultrasonic waves before they reach the area that is to be inspected.

Preferably, at least 1.5 meters should be left between the transducer ring and the beginning of the areathat needs to be inspected.

In order to aid fault-finding later, do not place the ring exactly between two features. It is usually bestto place the ring so that the distance to the closest feature on one side of the ring is twice the distanceto the closest feature on the other side of the ring.

If there is a very large reflector (such as a flange) in the test range, it is usually best to place the ringeither

• as close as possible to the feature (so that the reflection is within the dead zone), or

• as far away as possible (so that the reflection is near the end of the test range).

If performing multiple tests on the same pipe, the distance between tests should be arranged so thatthere is some overlap between subsequent tests. The expected range will vary greatly depending onfactors such as the pipe condition, type of supports, wrappings, etc. Twenty meters is a normal value fornon-wrapped pipes. The range can also be limited by the number of welds through which the sound hasto pass. A general rule of thumb is that the maximum test range is limited to only 6 butt welds in thehigh frequency regime and 12 in the standard frequency regime. More examples of predicted ranges aregiven in section 3.4.

If the pipe is very heavily corroded at the intended test location, it is recommended that a new testlocation be identified. The heavy corrosion will greatly reduce range because of it increases signal loss.In addition, if the pipe is extremely corroded, it is possible that applying the rings could damage thepipe.



4.2 Clean pipe 36

Figure 4.1: (a) Preparation of test location and (b) necessary clearance required around pipe at testlocation.

4.2 Clean pipe

At the selected location:

• Remove any insulation / thick coating / earth that is blocking access to the area where the ringswill be applied. If there is heat tracing on the line, this will need to be pulled away so that thering can fit between the tracing and the pipe. In such a case, the tracing will normally need to beturned off and a larger section of insulation will normally need to be removed. (See figure 4.1).

• Remove any large paint beads on the bottom of the pipe. On some horizontal painted pipes, anaxial bead of dry paint may have formed on the bottom. If this protrudes significantly it must befiled down in order for the ring to be correctly fitted to the pipe.

– For the inflatable rings, 210 mm will be needed along the length of the pipe and about 60 mmin the radial direction.

– For the fixed rings, about 300 mm will be needed along the length of the pipe and about 75mmin the radial direction.

• Scrape away any loose material such as flaking paint, mud, or corrosion. It is suggested thatsomething like a 1 inch paint scrapper is used to remove coatings and a stiff wire brush or fileis used to remove loose corrosion. If there is external corrosion present at the test location, it isimportant to try to estimate its depth and document it in the report.

Safety Note Suitable gloves should be worn while preparing the pipe surface.

Safety Note Be careful when scrapping heavily corroded pipes to ensure that no leaks are created.

Safety Note Turn off heat tracing before working on the pipes.



4.3 Check location 37

Table 4.1: Maximum warranty temperatures.Type of Ring Max Temp (C) Max Temp (F)Solid ring 125C 250FInflatable ring 70C 150FG3 Instrument 50C 120FCables 70C 150F

Safety Note Accessing the test location usually presents several hazards, ranging from animal bites tovehicle traffic; ensure that you are aware of what site specific hazards exist.

In general, most hard coatings (such as paint or fusion bonded epoxy) can be left on the pipe. Whilethe results using the older SE16 instrument may not be satisfactory with some pipe coatings, theWavemaker R©G3 provides much better penetrating power. During trials, it was possible to test directlythrough 4 mm thick epoxy coatings, however the signal to noise was decreased. Thick or disbondedcoatings can prevent energy from getting into the steel wall of the pipe. These cases can be detected bygetting very low transmission values from the collected calibration data (and the reported S/N ratio onthe status screen). In such cases, the results may be improved by removing the paint surface so that thetransducers make contact with bare metal.

4.3 Check location

4.3.1 Temperature

The equipment has certain temperature limits that should not be exceeded. The maximum temperaturescovered under the equipment warranty are listed in table 4.1. When near hot pipes, check the temperatureyourself. Quoted line temperatures may be lower than what is experienced on site. The multi-meterssupplied with the spares kit have a temperature function. If these are not available, you can touch theside of a previously damaged module to the pipe, if it melts within 30 seconds the pipe is too hot.

High temperature

The equipment has been used on pipes that are hotter than these limits (removing its warranty). Ifusing the equipment on hot pipes, please be aware that temperatures above 170◦C (340◦F) can quicklycause irreversible damage to the expensive standard transducers. (The glue can melt at 180◦C; the PZTcrystals de-polarize at 250C.) Temperatures between 70◦C and 170◦C mainly damage the rings, modules,and internal cables. In these situations, the following precautions must be taken.

• Agree that any heat damage caused to the rings will not be covered by the warranty of the ringand your company will be charged for any heat damage caused to rental rings.

• Ensure that the ambient temperature around the pipe is sufficiently low for your own personalsafety.

• Wear suitable gloves.

• Check the temperature yourself.

• Wrap the pipe in several (3-4) layers of aluminum foil to act as a heat shield over at least 2 feet(600 mm) of the pipe.

• Also wrap inflatable rings in layers of (thick) aluminum foil.



4.3 Check location 38

• Spend as little time as possible on the pipe.

• Have information such as site already entered into the laptop so that a test can started as soon asthe ring is inflated.

• Remove the ring as soon as data is collected.

• Allow time for the rings to cool between tests.

• Always check the received signals for evidence of faults.

• Have thermal protection wrapped around the cables.

Low temperature

The transducers themselves work fine in cold temperatures (although the modules do get bittle). Themain problem with testing cold pipes is that there must not be any ice formed between the transducerface plates and the pipe. Chemical ice removal agents will usually work best (giving the most amount oftime to get the ring on before the ice reforms). We have generally found that if the pipe temperature islower than about -20C, it is not possible to get the ring on quickly.

Please note that compressed corrosion often occurs on cold service pipes between the pipe and theinsulation. It typically appears like little barnacles and usually highly attenuates the signal. In this case,it is necessary to completely remove the corrosion at the test location (under the ring) and it may benecessary to test in the low frequency regime.

Safety Note Many plants do not permit certain cold service lines (for example ammonia lines) to bedisturbed while they are in operation.

Ambient temperature

If the ambient temperature is quite high (> 40C, > 100F ), it may be necessary to take precautionsprevent the Wavemaker R©G3 instrument from overheating. Some suggestions are:

Shade - Keep out of direct sunlight, covering with a reflective tarp when appropriate.

Cool - Long transducer cables are available that allow the instrument to remain in a cool place (such asan air-conditioned car) while testing is performed in a hot enviroment.

Insulate - Standard plastic food coolers can usually be modified to encase the Wavemaker R©G3 and stillallow the cables to exit.

When the ambient temperature is very low (below freezing), there are several precautions that should betaken.

• The batteries in the Wavemaker R©G3 drain much faster when they are cold. Therefore, the instru-ment should not be left outside for long periods of time. It certainly should not be left overnightin an unheated vehicle.

• The instrument should be allowed to warm up before starting to charge the batteries.

• The modules and the transducer retaining screws become brittle in cold temperatures. Please becareful to avoid any ’shock’ loads on the inflatable rings.



4.4 Apply transducer rings 39

4.3.2 Thickness check

A standard UT set or a good quality thickness gauge should always be available on site. The Wavemaker R©G3Pipe Screening System can only detect changes in the cross section of the pipe. Therefore, it is importantto know the condition of the pipe at the test location in case there is a problem that extends unchangedfor the entire length of the pipe (for example a groove on the bottom of the pipe). Knowing the localcondition significantly aids future reporting requirements and frequently saves overall time. Manual UTis also recommended later for immediate follow-up checking.

When performing the thickness check, it is advised that one

• Scans to look for evidence of internal corrosion or pitting. When generalized corrosion or pitting ispresent it appears as large attenuation in the processed trace. However, from this processed tracethe nature and the severity of the general corrosion is very difficult to determine. Therefore, thiscomplementary scan can be very useful. (Please ensure that a high enough resolution probe is usedto find small pits.)

• Adjusts the overall test range according to overall observed corrosion. If some generalized corrosionis found, the test range will be reduced and the spacing between test locations will probably needto be reduced.

There is a box on the front collection dialog (described later in section 5.3) for recording the measuredpipe wall thickness.

4.4 Apply transducer rings

4.4.1 When using solid rings

The procedure for fitting a solid ring onto a pipe is shown in figure 4.2 and can be described by thefollowing steps.

• Check the pipe temperature to ensure that it is below 125◦C.

• First the top half of the ring (the half with the spring clip and the button) should be clipped ontothe top of the pipe under test at the test location (figure 4.2(a)). The split between the two halvesof the ring should be placed horizontally if you want to be able to use the orientation analysis tooldiscussed in later sections.

• Next the bottom half of the ring should be positioned below the top half, making sure that theLemo R© connectors on both halves are pointing in the same direction as shown in figure4.2(b).

• The clamps should then be swung inwards into position and tightened. The clamps are tightenedcorrectly when the two halves of the ring contact each other on both sides of the pipe. Care shouldbe taken to ensure that the ends of the clamping bolts locate in the dimples provided on the twostainless steel plates on the top half of the ring.

• Ensure that all transducers are in contact with the pipe. To do this, put the ring on the pipe andloosen the capscrews on the outside of the ring with a 4mm Allen key until they lift off 1 to 2mm (a sixteenth of an inch) from the milled part of the ring and become loose. At this point, thetransducers should be pressed against the pipe by the internal springs. It is very important thatall transducers are in good contact with the pipe. If any of the capscrews appear to be raised bymore than 2mm, they should be tightened until finger tight and then loosened a single turn. Thisis especially important for the transducers closest to the divide between the two halves. Leaving




Figure 4.2: Fitting a solid ring to a pipe.

the transducers extended can damage them as they are dragged across the surface of the pipe. Inaddition, having the initial size properly adjusted will reduce the effort required to clamp the ringonto the pipe in subsequent tests.

The ring-cables do not need to be disconnected from the ring during the fitting process, although in somesituations it may make fitting easier. If the cables are attached to the ring halves while the ring is beingfitted, be very careful not to ever pull on the cables.

Some new instruments are supplied with cables that have right angle connectors on one end and straightconnectors on the other end. New (mid-2007) solid rings allow either end to be connected to the ring.However, on older solid rings, the right angle side must be connected to the instrument and the straightend connected to the ring.

4.4.2 For inflatable rings

When attaching inflatable rings, the following steps should be followed

• Make sure the temperature of the pipe is less than 70◦C.

• Make sure that the ring is completely deflated (from it previous use).

• Wrap the ring around the pipe and attach the two ends of the clamp in one of the three settings.The clamping thumb screws should fit squarely within the holes in the sliding part of the clamp.If they do not penetrate into the provided holes, the ring could come apart when it is inflated andinjure the operator. The smallest feasible setting should be used, however the transducers do notneed to be pulled tight against the pipe at this point.

• Rotate the ring so that the clamp where it joins is precisely on the side of the pipe and the Lemo R©

connector is on the top half of the pipe. Following this convention allows the orientation analysistool to be used when examining the results. (Please note that the orientation is not set by the




position of the connector housing; it is set by the divide in the ring). The correct orientation wasshown in figure 3.3.

• Straighten the ring so that it is perpendicular to the axis of the pipe (to an accuracy of better thanone third of the spacing between the transducer in the module). This adjustment must be donecarefully because a 10 mm mis-alignment can cause noticeable differences. (The symmetry infor-mation is lost.) When testing with large diameter pipes that are not horizontal, it is recommendedthat a jig is created to help alignment. The jig may either hold the ring aligned on the pipe whileit is being inflated. Or the jig could allow a reference line to be drawn around the circumference ofthe pipe. This line can be used to help confirm that the ring was inflated at the correct orientation.

• Inflate to a few psi (so that the transducers just touch the pipe).

• Make sure that all of the transducer modules are straight (not tilted). All tilted modules should bestraightened by hand.

• Inflate to 20 psi (1.5 bar) for testing. The ring should be able to maintain this pressure during theentire test. Checking the pressure at the end of the test will allow slow leaks to be identified. Ifthere is a major leak, the ring will need to be returned to GUL for repair. If the coupling is poor(as identified later in section 5.1.3) the pressure can be increased to 35 psi (2.5 bar) to get a largersignal. However, the rings should never be inflated over this pressure.

Note 1. Do not inflate the rings unless they are wrapped around a pipe. Inflating an empty ring maydamage the internal wiring.

Note 2. In order to aid comparison between results (during reporting), it is important that thepressure is consistent between subsequent inflations of the ring. If the pressure is consistent(within 5 percent), then the amplitude will generally be consistent (within 5 percent).

Note 3. If it is raining, cover the ring with a plastic sheet to minimize any water ingress.

Note 4. Avoid dipping the ring through any puddles

Note 5. Ensure the main Lemo connector and the inflator valve are kept clean. Covering them withtape may sometimes be necessary.

Safety Note Ensure that the thumb screws in the clamps of the inflatables are well seated in their dimplesbefore inflating the ring.

Safety Note Never inflate inflatable rings over 35 psi (2.5 bar). The pump that is used must always havea pressure gauge.

Safety Note Be careful not to trap fingers when straightening modules or clamping the ring.

4.4.3 For combined inflatable rings

Combining inflatable rings together to make a larger ring is very prone to operator error. In addition, thebalancing between the segments is never as good as it is for a single ring. Therefore, it is recommendedthat exact size rings are used for all common sizes when possible. However, in some situations, ringsmust be joined together.

Note 1. Extra long curved arms are available for several sizes of large rings that allow them to testa pipe that is 2 inches larger in diameter than their nominal size. For example, long armson a 24 inch ring will allow it to test a 26 inch pipe.

Note 2. Small rings (6-18 inch) generally cannot be extended because the resulting gap would occupytoo large of a proportion of the circumference of the pipe.

When joining rings, there are two important limitations:



4.5 Connecting to the G3 42

• The total ring size must be appropriate for the pipe. In general, the sum of the diameters of thetwo component ring sizes should usually be 4 inches smaller than the pipe being tested. In otherwords, a 42 inch pipe could be tested using a 20 inch and an 18 inch ring.

• There should not be more than 4 inches or 25 percent difference (in diameter) between the tworings. For example, a 36 ring could be made from two 16 inch rings. It should not be made from a8 and 24 inch ring.

Combining two rings is physically quite easy. Simply connect the ends together. If you want to optimizethe system, the curved clamp arms should be replaced by ones of a radius to match the pipe beingscreened. However, this may not always be necessary. Contact GUL for advice.

One or two 24 pin Lemo R© cable(s) should extend from the instrument to each individual ring. Pleasebe extra careful with the cables, since they are very easy to damage in this configuration. The curvedarms on the ends of the clamps should NOT be reversed from their original orientation (or the wiringconfiguration will be wrong). It is important to check that the direction of both rings (the side of theconnection box that the Lemo R© connectors is on) is the same for the two rings.

When inflating the rings, it is quite important that both rings are inflated to the same pressure. A suremethod of achieving even pressure is to make a Y arrangement so that both rings are pumped at thesame time. A Y arrangement can be created by removing the valve inserts and attaching M5 pneumaticfittings to the inflation valve housings. However, a more common method to equalize the pressure is to:

• Inflate one ring to just over half of the operating pressure

• Inflate the second ring to the operating pressure

• Inflate the first ring to the operating pressure (Please note that if you inflate one ring fully, andthen the second ring fully, the first ring will end up at too high of a pressure)

The new Wavemaker R© WaveProG3TM

software should automatically recognize the combined ring andadjust parameters appropriately (the old SE16 implementation does not and requires that the rings aredeclared in the software).

4.5 Connecting to the G3

4.5.1 G3/Ring connections

When connecting the ring to the G3 instrument it is relatively easy to damage the large ring cables.Therefore, please observe the instructions in section 3.7 and figure 3.8 about how to handle the cables.The Wavemaker R©G3 instrument can cope with the rings being connected to any of the connectors onthe front panel. However, when two connectors are to be used (for example with two inflatable rings),it is recommended that that the two connectors that are used are not adjacent. Using non-adjacentconnectors (for example, A and C) maximizes the signal to noise ratio and minimizes the time requiredfor collection.

Safety Note Always ensure that the cables are routed so that they do not present a trip hazard.

4.5.2 Initial Coupling Check

It is important that all transducer ring segments are well coupled to the pipe. Section 5.1.3 describesa way that the coupling balance can be quickly checked when Wavemaker R© WaveProG3

TMsoftware is



4.5 Connecting to the G3 43

Figure 4.3: The ’Ring:Coupling’ screen on the Wavemaker R©G3 when the pipe is being rubbed with ametal object. In this example, there is a fault on the first channel of the ring.

running.

It is also possible to perform a quick coupling check from the Wavemaker R©G3 instrument alone.

• Select the ’Ring:Coupling’ screen.

• Adjust the gain so that the squares representing the signal received at the transducers are ’dancing’.

• Use a metallic object (such as wire brush or the tip of steel capped boots) to scrap the surface ofthe pipe about a meter away from the position of the transducer ring.

• Observe the squares.

If all of the transducer segments are well coupled, all of the squares should enlarge to about the same size.If one of the segments is much lower than the others (as shown in figure 4.3), then there is a problem.Ensure that the ring is well seated, has no tilted modules, has all transducers touching, is not stuck ondifferent thicknesses of paint, and has no failed segments.



Chapter 5

Collecting Data

There are two different ways to collect a test sequence when using the Wavemaker R©G3. Either thesequence can be controlled by an attached laptop (this is the default) or a sequence can be triggeredindependently by the user interface on the Wavemaker R©G3 instrument.

This chapter discusses some common terms for the collection of data and then describes how data canbe collected using either the PC or the Wavemaker R©G3 interface.

It is assumed that at this point in the procedure the operator has already performed all checks required(see section 3.8), has logged on to the instrument (see section 3.6.4) and has attached the ring to the pipe(see chapter 4). It also assumes that an appropriate ring configuration (or multiple ring configurations)has been chosen (section 3.3) for the application.

5.1 Checking parameters

5.1.1 Ring parameters

Before beginning a collection, it is important to check that the correct ring parameters have been detectedby the software.

The ring information is displayed on the Collect tab of the WaveProG3 software (as shown in figure 5.1).On this tab, the ring definition code is shown and the module width configuration (if relevant) can beselected. These must match the actual ring configuration (the module width setting is a measurement ofthe distance between the center of the two transducers in a module). If the correct ring is not indicated,please choose the menu option Actions:Redetect Ring to refresh the ring information.

On the Wavemaker R©G3 instrument, the detected ring type can be seen on the ’Ring:Info’ screen.

5.1.2 Battery and Temperature

The beginning of the test is also a good time to check the battery level and temperature of the instrument.The battery level is shown on the status bar (of both the software and the instrument display). Thetemperature inside the case can be seen on the status tab of the Wavemaker R© WaveProG3

TMsoftware

and the ’Info:Main’ screen on the instrument. The instrument should be able to operate between 0◦C and60◦C, however, temperature warnings will begin appearing at 48◦C. At this point, the measures outlined



5.2 Collection protocol 45

Site

Info

Not

esC

apac

itanc

ere

sults

Couplingresults

Ring and Module configurationPipe wall information

Protocol Selection

Figure 5.1: An example ’Collect’ screen.

in section 4.3.1 to control the temperature of the Wavemaker R©G3 should be taken.

5.1.3 Capacitance and Coupling

For the first test at each location, it is recommended that the capacitance of the ring and the couplingis checked. The capacitance check provides a quick method of detecting faults that will later corruptthe data. The coupling tests to see whether significant energy is traveling through the pipe and whetherall of the different segments of the ring are equally coupled to the pipe. When running from a PC,these can be checked by clicking on the appropriate buttons on the collect tab. When running from theWavemaker R©G3 instrument, the capacitance can be shown on the ’Ring:Impedance’ screen (as describedin section 3.8). The coupling can be shown on the ’Ring:Coupling’ screen that shows the receivedamplitude of all active channels. Rubbing the pipe with a metal object should cause the received signalamplitude (represented by the height of the bars) to increase roughly equally for all of the channels.

If the coupling is low for any particular channels, try removing the ring, cleaning the pipe, and reattachingthe ring. If the coupling is low for all channels, any coating on the pipe may need to be removed. If thereare very heavy deposits on the inside of the pipe, then the only other option may be to try a differentring location (for example not at the bottom of a dip).

5.2 Collection protocol

The collection using the Wavemaker R©G3 is based on collection protocols, a series of parameters thatdescribe how the collection should be configured and when data should be gathered. Depending on thering that is attached and the module configuration that is selected, a list of protocols will be presentedeither on the PC or on the instrument. These protocols fall into the following four general categories.



5.3 Starting a test from the PC 46

Standard This protocol uses the configuration that has proven to be consistently good over a wide rangeof test scenarios. It is optimized to make the processing routines as robust as possible.

High Noise Filter This protocol performs a standard collection routine, however it forces the high passfilter to be set at its highest setting and increases the number of averages. This can lead to somephase distortion but frequently gives better results on short pipes that have a lot of ambient noise.Its dead-zone is the same length as for the Standard collection protocol.

Short Range Screening This protocol is optimized to reduce the dead zone as much as possible. How-ever, it is very susceptible to ambient noise and therefore cannot be used in all situations.

Extended Frequencies This option is only available to Level 2 operators, it collects data that is outsideof the region that has proven to be stable. Therefore, extreme caution is required when interpretingthe results. (Please note that the range of frequencies that are displayed for a standard collectionare smaller than the full range that was collected. A level 2 operator can select View:ProcessedData:Extend Frequency Range to view the full range.)

High Ambient Noise - Avoid This protocol is optimized to improve performance when there is anextreme amount of random ambient noise in the test location (for example off-shore). However,the results show more processing noise and the dead zone performance is very poor. False echoesare also very common when using this protocol. Therefore, it is usually recommended that if acollection is done with this protocol, one is also done with the standard and High Noise Filterprotocols.

5.3 Starting a test from the PC

In order start a test from a controlling computer, you must ensure that

• The user that is currently logged onto the computer has Administrator privileges (if the firmwareon the Wavemaker R©G3 instrument is older than 10 August 2005).

• Wavemaker R© WaveProG3TM

has been installed on the computer and that the version is compatiblewith the current Wavemaker R©G3. (The software will display a message box if it is not compatible.)

• Wavemaker R© WaveProG3TM

is started (via the icon on the desktop or the Start Menu) and iscurrently displaying the ’Collect’ tab.

• The status bar is indicating that the software has connected to the instrument and has recognizedthe ring.

Before starting a test from a PC, it is important to confirm that the correct pipe and module type areselected.

In addition, there are 5 boxes on the collect tab (shown in figure 5.1) that must be completed. Theseinclude:

• Site This is the highest level of tracking that of the test location. The contents of this box usuallyform the name of the directory in which the test file will be stored.

• Pipe This is meant to help a track and individual pipe that is being tested. By using a uniquename, it is easier to group several tests on the same pipe together. The contents of this box (andthe Datum and Distance boxes) usually help form the filename that the test is stored under.

• Datum This is meant to help locate a test on the pipe. It is usually meant to be used withDistance to specify a feature on the pipe and the distance away from that feature that the test wasperformed. However, other naming conventions can be used.



5.4 Starting a test from the Wavemaker G3 47

• Distance See the explanation for ’Datum’.

• Range This is the test range over which data will be collected. However, it may not be the rangeover which the data will be meaningful. It is always recommended that more data is sampled thanis thought necessary. For example, if testing a 13m spool piece, it recommended that the range isset to 20m. (Note: to change the input units, select View:Preferences

At this point a collection can be started by clicking on the ”Collect” button or pressing F7.

While the collection is being performed, the remaining boxes on the Collect tab can be completed.

• Report Notes These are notes that will appear on the completed report.

• Operator Notes These notes will be saved with the file, but will not appear on the final report.

• Measure Pipe Wall The measured wall thickness of the pipe wall should be entered in here. Anultrasonic scan of at least several points around the circumference of the pipe should be performed.

• Extra Info Extra information about the pipe, such as the coating and the types of supports canbe entered via the dialog that opens by clicking on the extra info button.

As the collection sequence is being performed, the capacitance and coupling graphs will be updated withthe most up-to-date information. On the coupling graph, the green bars represent the amplitude of thedirectly transmitted signal and the red bars are a rough estimate of the level of ambient noise.

When the collection is finished, the data is automatically uploaded from the Wavemaker R©G3 instrument,analyzed, and saved on the local computer. The format of the filename that is automatically created canbe controlled by the View:Preferences dialog.

5.4 Starting a test from the Wavemaker G3

In situations when it is not feasible to connect the Wavemaker R©G3 instrument to a computer duringdata collection, the Wavemaker R©G3 can collect data independently. To do so

• Press the ’Go’ button.

• Select the range using the ”Range Up” and ”Range Down” buttons

• Select the module width configuration (if using an inflatable with variable width modules)

• Select which protocol to use

• Click on the ”Start” button

These steps are shown in figure 5.2.

The instrument runs through the collection sequence showing a selection of received data traces as thedata is collected. The collection can be stopped at any time by pressing the ’Esc’ button.

Once the collection is complete the sequence complete screen (shown in figure 5.3) is displayed. This filewill remain on the device until the Wavemaker R©G3 is turned off. If you want to preserve the file so thatit will be present after the instrument is turned off, then you will need to click on the ”Save to Flash”button to save the result file on the internal compact flash memory, or ”Save to USB” if a USB storagedevice is connected to the Host connector on the front panel. There is only a limited amount of space



5.4 Starting a test from the Wavemaker G3 48

a) b)

c) d)

Figure 5.2: The ’Go’ screens that are used to start a collection from the Wavemaker R©G3 instrument.

Figure 5.3: The ’Sequence complete’ screen on the Wavemaker R©G3. This screen displays the filenamecontaining the results and provides options for permanently saving it.



5.5 Check transducer ring operation 49

on the internal flash (typically 256 MB), so files will need to be frequently deleted via the ’Device:Files’screen.

The raw data file (with a .G3R extension) can be transferred to a PC for analysis in one of two ways:

• The file can be copied from its disk to a temporary location on the PC and it can be opened fromWaveProG3 (with the standard File:Open command), or

• If the file was stored in the system flash memory or the file is still on the disk drive represent-ing the Wavemaker R©G3, the operator can run Wavemaker R© WaveProG3

TMand wait for the

Wavemaker R©G3 to connect. Selecting Actions:Upload from G3 will present a list of files thatare available for uploading and processing.

Once a raw data file has been opened, it may need to be processed in WaveProG3 by selecting Ac-tions:Reanalyze. The raw data file (with a G3R extension) will be automatically converted into aprocessed file (with a WG3 extension). The site information that is usually entered from the PC will beset to be unassigned.

5.5 Check transducer ring operation

As part of the analysis procedure, the software checks the raw data for faults. Major errors are flagged andprevent further processing steps. A minor error such as one channel having a slightly smaller amplitudethan the others is shown as a warning. It is important to ensure that the data is valid before moving onto the next stage of data analysis. This section describes way of examining the data for faults.

5.5.1 Raw Data

The results of the automatic raw data tests can be seen on the ’Status’ tab. The plot on the right allowsseveral items to be checked.

Amplitude Balance The amplitude compensation for all of the segments should be between 0.5 and1.5. If any segments are outside of this range, the ring may need to be reattached taking more carethat all of the transducers in all of the segments are in good contact with the pipe.

Raw Data This view shows an example of the raw data obtained from each of the segments. Manysubtle faults can be detected by examining this output. Therefore it is very helpful to look at thisdisplay frequently and become accustomed to what the data should look like. An example is shownin figure 5.4.

Capacitance This view shows the result of the capacitance test that is automatically performed as partof the Wavemaker R©G3 sampling sequence.

The importance of ensuring that all of the data is good can be seen in figure 5.5. There was a fault thatcaused very poor data to be collected on one of eight channels. As a result of this fault the data in parta) is quite noisy. Repairing the fault allowed the result shown in part b) to be achieved.

5.5.2 Ambient Noise

Several of the warnings are triggered when the signal to noise ratio is considered too low or the amplitudeof the unwanted frequencies is larger than the amplitude of the desired frequencies. These problems




0.0 1.0 2.0 3.0

00

200200

400400

600600

Time (ms)

Am

p (

mV

)

Pulse Echo Traces

Flat area (during transmission)

Erratic area (amplifier saturation recovery)

Real signal

'Modal' and transducer ringing

Noise level, amplutide, and pattern should be similar on all channels

Figure 5.4: An example of the plot of the raw data traces. When the data is valid, All of the channelsshould have approximately the same noise performance. Typically, there is a flat section (correspondingto the length of the outgoing signal), an erratic section (amplifier recovery), a slowly decaying ringing,and then real signal. There should not be any sharp spikes.

-100-100 -50-50 00 50500.00.0

0.20.2

0.40.4

0.60.6

0.80.8

1.01.0

Amp (mV)Am

p (

mV

)

+F1+F

1 +F2+F

2 +F3+F

3 +F4+F

4-F1-F

1-F2-F

2-F3-F

3-F4-F

4-F5-F

5-F6-F

6

Distance (ft)Distance (ft)

a)b)

-100-100 -50-50 00 50500.000.00

0.100.10

0.200.20

0.300.30

0.400.40

0.500.50

Amp (mV)Am

p (

mV

)

+F1+F

1 +F2+F

2 +F3+F

3 +F4+F

4-F1-F

1-F2-F

2-F3-F

3-F4-F

4-F5-F

5-F6-F

6

Distance (ft)

Figure 5.5: An example of the effect of having very poor data from one channel. When one channel wasnot working the result shown in a) was achieved. When all channels were working the result shown in b)was achieved.




normally occur when there is a large amount of ambient noise present. The ambient noise can be easilyseen by switching to the ’Analyze’ tab and choosing View:Raw Data:Frequency:Single Unfiltered.This view shows the raw data before the digital filters have been applied. In some situations, it ispossible to identify a range of frequencies where there is a lot of noise. By switching the frequency regime(by changing ring types), it may be possible to avoid the frequencies where outside noise is affectingthe results. If it is not possible to avoid frequency of the noise, then it is recommended that the datacollection is repeated with the ’High Noise Filter’ collection protocol selected.

In very rare circumstances, the ambient noise may swamp the electronics even when they are runningat their lowest gain. This condition can be detected by observing that the gain level remains at 10 dBfor the entire collection and that the raw data signals have square tops for their entire duration. If thishappens, it is recommended that the pipe is wrapped in one or two layers of electrical or duct tape andthat the ring is placed over the electrical tape.

5.5.3 Calibration data

The Wavemaker R©G3 automatically samples three calibration signals with each data collection. Thesesignals can be seen in the time domain by choosing View:Raw Data:Time:Calibration Data, or inthe frequency domain by choosingView:Raw Data:Frequency:Calibration Data. This data allowsvarious parameters, such as the true signal to ambient noise ratio, to be determined. An example of thetime display is shown in figures 5.6 and 5.7.

The three types of collected data include

Direct transmission - Green . This is the signal as transmitted from one row of transducers to thenext row. It is used to measure how efficiently energy is coupled into the pipe. The softwareautomatically processes this data to draw the small DAC prediction crosses discussed in a latersection.

Ambient noise - Red . This signal was received by the transducers when the Wavemaker R©G3 was nottransmitting. It represents the noise in the pipe that is created by other sources. Its amplitude incomparison to the directly transmitted signal is reported on the status screen.

Crosstalk - Blue . This signal is used to determine the amount of error expected in the measurement ofthe directly transmitted signal. It is gathered by transmitting and receiving on two unused channelsthat have similar wiring configurations to those used for the direct transmission. The amplitude ofthis signal is usually caused by electrical cross talk (as opposed to real data).

In the figure with noise (figure 5.7), notice the noise present on the red noise trace compared to the signalsize on the green trace. Further note the noise on the green trace that occurs before time zero that doesnot appear on a quiet pipe shown in figure 5.6. The ratio of the amplitude of the signal shown in thedirect transmission to the amplitude of the noise is reported on the status screen in dB. It is recommendedthat you achieve a minimum of 40 dB S/N ratio. The signal to noise can often be improved by

• Increasing the number of averages

• Improving the coupling of the transducers onto the pipe wall

• Testing at a higher frequency when there is a lot of nearby ambient noise.




0.00.0 1.01.0 2.02.0 3.03.0 4.04.0

-20-20

00

2020

4040

Time (ms)

Am

p (

mV

)

Figure 5.6: An example of the plot of the calibration data (in the time domain) when there is littleambient noise.

0.00.0 1.01.0 2.02.0 3.03.0 4.04.0

-10-10

00

1010

2020

Figure 5.7: An example of the plot of the calibration data (in the time domain) when there is highambient noise. Notice the noise present on the red noise trace compared to the signal size on the greentrace.



Chapter 6

Analysis Tools

This chapter discusses some of the fundamental tools that can be used to interpret the data. These basetools will be used in the next chapter (Chapter 7) that outlines an example analysis procedure.

6.1 Overview

Table 6.1 lists the basic interpretation tools that are typically applied to Wavemaker R© results.

The first tools (common sense and visual identification) are common across most inspection techniques.They are especially important in guided wave testing as they dictate how the inspection is configuredand what the inspector expects to see in the results. Deviations from the expected result (as revealed bythe later tools) can often reveal defect types that are not otherwise detectable.

Each of the later tools is discussed in detail in the remaining sections of this chapter.

6.2 Reflected Amplitude

The propagating guided waves reflect from any change in stiffness of the pipe. In the standard frequencyregime, this change is normally due to changes in the cross section of the pipe. Therefore, Wavemaker R©

WaveProG3TM

reports all changes as this.

For through wall defects, the relationship between reflected amplitude and cross sectional change islinear. If 25 percent of the circumference of the pipe is removed, nearly 25 percent of the transmittedwave is reflected back. The exact reflected amplitude from a change in cross section that does not extendentirely through the wall depends on many factors, including the axial length of the feature and theexact percentage of wall thickness. However, for the purposes of screening pipe, these small effects canbe ignored and a simple linear relationship can be assumed for all defect depths.

6.2.1 DAC Surfaces

As you move farther away from the transducer the amplitude of the transmitted pulse decreases. TheWavemaker R© WaveProG3

TMsoftware uses a DAC (Distance Amplitude Correction) surface to track how

the signal amplitude decreases as the position from the ring is increased and the frequency is increased.By predicting the signal amplitude at different locations, the relative size of reflections can be better



6.2 Reflected Amplitude 54

Table 6.1: Summary of Interpretation Tools.Primary Tools Used for any type of inspectionCommon Sense What would you expect to find? A good history of the line and prediction

of expected defect types allows time and energy to be concentrated on theareas of most interest.

Visual inspection What did you find? It is extremely important to correlate the guidedwave data with what can be observed visually. Do not ignore valuableinformation such as which supports are touching, where are the corrosionstains, is the pipe well bonded as it enters a wall.

Fundamental Tools Used for all analysis of the guided wave dataReflected amplitude How much of the guided wave energy is reflected from the feature and

how much is transmitted through. Comparing the amplitudes of both thecurrent and subsequent features to the DAC curves is important for bothclassification and sizing.

Symmetric / non-symmetric nature

By observing the relative amplitudes of different guided wave modes (shownas red and black on the result trace), it is possible to determine if a feature isevenly distributed around the circumference of the pipe (such as a weld) orwhether it is concentrated in a certain portion of the pipe (as most corrosionis). Figure 6.3 shows how the circumferential extent can be estimated.

Shape of the reflectedpulse

If the feature is relatively short along the axis of the pipe (such as a weld)the reflected pulse will be quite clean and even. If the feature has a signif-icant axial length (as many corrosion patches do) then the reflection willbe irregular and change with frequency.

Additional Tools Used to extract more information from certain reflectionsOrientation (C-Scan) It is possible to determine the approximate circumferential orientation of an

isolated defect. Combined with the expectations and visual observations,this information can help classify various defects as well as focus any follow-up investigations.

Behavior at different fre-quencies

The behavior of the reflections as the frequency regime is changed canreveal a lot of information about a reflection, especially if the reflection iscaused by the overlapping of multiple features at the same axial position.

Phase of reflection On clean echoes, it is possible to extract the phase of the reflection, whichindicates whether the reflection is from an increase or a decrease in theimpedance of the pipe.




judged. There are many ways of determining the signal amplitude at a point away from the transducerrings. Many of these are only covered as a part of Level 2 operator training. In normal operation, themost common method of determining the decay is to match the decay of consistent features such as welds.It is this method that is described in section 7.4.1.

The decay of the transmitted signal is due to several effects:

• The attenuation of waves propagating in the (steel) pipe (which on its own is quite small for metalpipes at our operating frequencies).

• The energy absorbed (and converted to heat) by the visco-elastic nature of most coatings andlinings. This type of attenuation is also referred to as damping in other parts of this document. Itbehaves in similar ways to material damping in conventional high frequency UT (higher frequenciesare attenuated more)

• The leakage of energy from the pipe into the surrounding environment (for example earth the pipeis embedded in). This attenuation effect can be compared to beam spread in conventional UT(lower frequencies spread faster (for a fixed probe size)).

• The loss in transmitted amplitude when some of the energy is reflected back to the transducer ring(for example from welds and general corrosion). This effect can be compared to scattering from acoarse grain structure that occurs in high frequency UT (higher frequencies are scattered more).

The amount of decay that is experienced can depend heavily on the frequency of excitation. This effectmust be accounted for when later attempting to compare the size of a reflection to the 100 percent trans-mitted amplitude. Wavemaker R© WaveProG3

TMcan accommodate all of the these decay types and allows

them to be frequency dependent. Instead of calculating a single decay at a single frequency, Wavemaker R©

WaveProG3TM

calculates a DAC surface that maps the estimated amplitude of the transmitted signalin both the distance and frequency domains. When displaying any given frequency, a slice through thissurface is extracted to calibrate the displayed results.

From the estimated transmitted amplitude, up to four DAC curves can be displayed. These are set torepresent the expected amplitudes for various features, however, their values can be changed as describedin section 6.2.2. The four default levels are:

Flange DAC representing the expected amplitude of a reflection from a flange (roughly 100% of theamplitude).

Weld DAC (defaults to 14 dB below flange DAC curve) which roughly corresponds to a 25 percentchange in cross section. This is the predicted size of a weld reflection in the standard to highfrequency regime in an average size pipe. By convention, this DAC curve is usually adjusted toalways be at the height of the weld echoes, even if they are not true 25 percent reflectors. Thisconvention means that the cross sectional loss on large diameter pipes are likely over-estimated. Amethod of setting this DAC level more accurately is discussed in section 6.2.2.

Call DAC (defaults to 26 dB below flange DAC curve) which roughly corresponds to a 10 percentchange in cross section. It is typically used as threshold level for classifying the severity of anydefects that are found.

Noise DAC By default, this level (initially set at 32 dB below flange DAC curve) corresponds to abouta 5 percent change in cross section of the pipe. It is commonly used as a estimation of the coherent(processing based) noise. It can also be used as a convenient classification size. It is possible toadjust the relative height of the Noise DAC curve in the Configure:DAC Levels dialog. (seefigure 6.1).

The different DAC curves can be turned on and off by selecting View : DAC Curves and then theappropriate curve from the pop-up menu.




Figure 6.1: The Configure:DAC Levels dialog.

In addition to the dashed lines that are drawn to indicate the DAC levels, a small colored cross is drawnat the ring position (on the ’Analyze’ screen) to indicate the height that Wavemaker R© WaveProG3

TM

predicted for the transmitted amplitude (based on the calibration data). This cross has the same coloras the DAC level that it is associated with; it will not be drawn if Wavemaker R© WaveProG3

TMdetects

collection errors or its predicted error margin is more than 50 percent of its value. These calibrationvalues can be useful when there are not many easily classified features. An example of the ’call’ cross canbe seen in figure 7.4.

6.2.2 Manually Adjusting DAC Levels

The parameters that are used for the DAC surfaces can be adjusted manually via the Configure:DACLevel menu option, which displays the dialog shown in figure 6.1.

The first section, which is labeled ’DAC Modifications caused by features’, allows the inspector to changethe default DAC modifications that are automatically applied for certain feature types. For example, bydefault, there is a frequency dependent drop that is applied at every weld. If this drop is too large or toosmall, it can be changed (for all welds at the same time), but adjusting the value from ’Default Values’to something like ’Half Size’ or ’Twice size’. The default drops can also be disabled by selecting ’Do notinclude’. Features other welds that have drops associated with them (for example bends), are adjustedby modifying the pull-down beside ’Other Feature Drops’. Similarly, the extra decays that are associatedwith coatings, embedded sections, and corrosion (that has a length associated with it) can be globallychanged via the ’Base Feature Decays’ setting. In addition to this global setting, the drops and decaysassociated with a particular feature can be adjusted via the ’Feature Detail’ dialog shown later in figure7.5. This option allows for fine adjustment of the DAC curves to represent the real effects of attenuation.

The next section specifies four parameters that are used to define the actual DAC surface.

• mV represents the amplitude of the outgoing signal (at the ring position) at 30 kHz. This shouldroughly correspond to the level at which the flange DAC crosses the zero axis.

• dB/kHz defines how the outgoing amplitude (specified under mV) changes as the frequency




changes. Specify zero for this value if the same outgoing signal height should be used for allfrequencies.

• dB/m specifies how the amplitude signal decays with distance (for a 30 kHz) signal. This valuerepresents the base decay (it is further modified by any feature decays along the propagation path).

• (dB/m)/kHz defines how the decay rate (specified under dB/m) changes as the frequencychanges.

The bottom section of the dialog is used to determine at what reflection amplitudes, the DAC curvesshould be drawn. There are several options.

Use Legacy Defaults, which matches the values used for the SE16 software. All welds are assumed tobe -14dB reflectors (roughly 28% changes in cross section).

User Override Values, which set the DAC levels to whatever values have been manually entered belowfor the Noise, Call, and Weld values. These can be defined as either dB drops or ECL (cross sectionchanges) by selecting either the ’dB’ or ’ECL’ radio button.

Calculate From Weld, which uses the measurements specified under ’Base Pipe’ and ’Weld Cap Di-mensions’ to calculate the theoretical reflection ratio for a weld of those dimensions at the frequencycurrently being displayed. The weld DAC is then set to match this level and the Call and NoiseDAC levels are set as proportions of this calculated weld DAC level. When this options is selected,it should be noted that

• The units default to the default wall thickness units defined in View : Preferences.

• The Weld cap height should be the height of the weld cap above the outer wall of the pipe.(It is not the total thickness of the weld).

• If this option is selected and the weld dimensions are not set, then default DAC levels areused. There is a different selection (’Default to Legacy or ’Default to User’) for when it shoulddefault the Legacy values or the User Override values.

• As the frequency is changed, the actual DAC levels will change with it.

• When using this option, the reported changes in cross section (when using the pointer tool) willmatch measured changes in cross section much more accurately. This is especially importantfor certain inspections when there is limited access for follow up inspection (such as casedcrossings).

6.2.3 Cross sectional area change

Provided that the DAC curves are set correctly (as described in section 6.2.1) for the entire range ofthe test, it is possible to estimate the approximate cross sectional area change of any feature. To do so,compare the maximum height of its reflected signal to the height of the various DAC curves at the samedistance. For example, if the maximum peak for a reflection is midway between the call (10 percent) andweld (25 percent) reflections, the cross sectional area change can be roughly estimated as between 15-20percent. The percentage change can be distributed in any pattern around circumference (see the nextsection for information about how to estimate the distribution). Please remember that the displayedreflection represents the sum of all features within the axial resolution of the test (see section for 6.6.1,on how to change the resolution of the test.)

A quick way of getting a more accurate estimate of the cross sectional area change is to click on thepeak in the ’analyze’ screen and read the predicted cross sectional area change on the status bar. Pleasenote that the cross sectional area change is usually abbreviated as CSC. However, another abbreviation(ECL) for Estimated Cross-sectional area Loss is often used interchangeably.



6.3 Symmetry / Circumferential Extent 58

'H-V' Tool 'Sum' Tool

Figure 6.2: Display with the Horizontal and Vertical components separated.

In addition, there is a display type (selected by View:Processed Data:Feature ECL or the pull-downdisplay type) that shows a bar graph of estimated ECL/CSC for each of the defined features. Once again,it is important to emphasis that the DAC curves must be correctly defined for the ECL/CSC estimateto be accurate. The ECL/CSC value can also be displayed in the table on the ’Report’ screen.

6.3 Symmetry / Circumferential Extent

The Wavemaker R©G3 Pipe Screening System always transmits waves that have the same phase andangular displacement direction at any point around the circumference of the pipe. We refer to thesewaves as symmetric. If a symmetric wave interacts with a feature (such as a weld) that is also symmetric(the same at all points around the circumference) only a symmetric wave is reflected. This symmetricreflected wave is detected by the system and shown on the processed trace as a black curve.

If the symmetric wave interacts with a feature that is not symmetric (is not the same at all points aroundthe circumference) and the system is operating in a positive frequency regime, there are several typesof waves that are reflected. One of these is the symmetric wave that is presented in the results as theblack trace. Two other waves are called flexural waves; they are not symmetric around the circumferenceof the pipe. By detecting the relative amplitude of these waves, it is possible to estimate the degree ofnon-symmetry. There are two ways to display the non-symmetric waves.

Sum This default displays the maximum non-symmetry at any orientation as a single red trace.

Horizontal/Vertical This view splits the non-symmetric waves into two different curves:

Red The red trace represents the amount non-symmetry between the top and the bottom ofthe pipe (provided that the ring is placed on the pipe correctly).

Magenta The magenta(purple) trace represents the non-symmetry between the two sides of thepipe.

The orientation display can be changed by clicking on the ’Horz-Vert’ toolbar button as shown in figure6.2. This ’splits’ orientations. Pressing the ’Sum’ toolbar button reverts back to a single red curve thatis the sum of all of the non-symmetric components.



6.3 Symmetry / Circumferential Extent 59

0%0

Red

/bla

ckR

atio

Circumferential Extent

1

50% 100

When the feature does not Extend

very far around the circumference

RED ~ BLACK

When the feature extends significantly around the circumference,RED << BLACK

%

Less SeriousMore Serious

100%50%~20%

Figure 6.3: The circumferential distribution of a defect can be estimated by the ratio of black and redtraces. Dividing the difference in heights of the red and black traces (shown in blue above) by the totalheight of the black trace (shown in green above) and multiplying by 100 gives an approximation of thereported circumferential extent in percent.

By measuring the relative heights of the black and the red traces it is possible to predict what portionof the circumference is affected (for most common defect types). Figure 6.3 shows how the ratio betweenthe two traces changes as the circumferential distribution of the wall loss changes. This figure also showsa quick way of reporting the circumferential extent as a percentage of the pipe that is affected (by thechange in cross section that was discussed in the previous section on Amplitude).

The relative ratios of the black (symmetric) and red (non-symmetric) traces can be summarized as

• If the Black trace is much greater than the red, the feature is symmetric around the circumference(similar to a weld).

• If the red trace is half of the size of the black trace, the effect of the feature extends roughly halfway around the circumference.

• If the red trace is the same size as the black trace, the effect of the feature is very localized aroundthe circumference of the pipe or the feature is very unevenly distributed around the circumference.

• If the red trace is bigger than the black trace, then there is either something wrong with the data,the guided wave has had to go around a bend, or there is a combination of features at the samelocation (for example corrosion at a support or within a weld). Further investigation of such echoesshould always be performed.

Note 1. When this document refers to symmetry it is always referring to axi-symmetry (symmetryaround the axis of the pipe); no other types or planes of symmetry are implied.

Note 2. When operating in a negative frequency regime, the circumferential extent of a feature cannotbe estimated.

Note 3. On longitudinally or spiral welded pipes, all weld reflections will contain some non-symmetriccomponents (red).

Note 4. If the ring was not mounted squarely on the pipe, all of the welds will appear red.



6.4 Shape 60

-10.0-10.0 -5.0-5.0 0.00.0 5.05.0

1.01.0

2.02.0

3.03.0

Distance (m)

Amp (mV)Am

p (m

V)

+F1+F1 +F2+F2 +F3+F3 +F4+F4-F1-F1-F2-F2-F3-F3-F4-F4

Too much redto be a weld

Many welds together(a pair of welded bends)

Irregular shape(welded support)

Irregular shape,Large amplitude

(Flange)

Regular shape,symmetric

regular size(classic welds)

Figure 6.4: An example trace highlighting various feature characteristics.

Note 5. Some operators attempt to predict wall loss by dividing the CSC by the extent. GUL dis-courages this practice since there is an extremely large error margin for small circumferentialextents. Even if the error margin were small, the result would only provide the average wallloss (which is usually not the critical parameter), the technique assumes an unrealistic flatbottom hole profile, the length of the defect can influence the result. Targeted complimentaryinspection is far superior.

6.4 Shape

The appearance or shape of a echo on the processed trace provides information on the axial length afeature. If the axial length is less than a quarter wavelength (the typical spacing between the two rows oftransducers), the reflected peak is usually quite ’clean’. If the features is longer than this, the reflectedpeak tends to look irregular (’rough’).

The roughness of the peak is caused by the complicated interference of the reflections from the beginningand the end of the feature. Since the interference changes as the frequency changes, the appearance offeatures with a significant axial length will tend to change as the frequency is changed (see section 6.6 onfrequency dependence). However, axially short features (less than a quarter wavelength at the the highestfrequency), should maintain a clean, smooth appearance as the frequency is changed. The example tracein figure 6.4 shows the difference between clean weld echoes and the irregular echo from a axially longwelded support.

Many (but certainly not all) forms of corrosion have significant axial length to them and therefore appearirregular. In contrast, many intended pipe features (such as welds and point contact supports) have verydistinct start and ends that are normally quite close together, which results in clean reflected signals.

Please note that when testing at low frequencies, certain features that are typically rough (such as flanges)can start to appear clean. This effect is due to the increase in wavelength as the frequency decreases.

Whenever a reflection is irregular, the inspector must be cautious when estimating amplitude. The inter-ference between the beginning and end of the feature may have reduced the maximum peak amplitude.When there are any irregular reflections, it is recommended that a large frequency range is examined andthat the CSC is estimated from the largest amplitude at any frequency.



6.5 Orientation / Unrolled Pipe 61

Figure 6.5: Display using unrolled pipe display to determine the orientation of a defect. The black radialplot on the right shows the orientation of the cross sectional change at the cursor location (current onfeature -F3). The arrow indicates the angle at which the maximum response was obtained.

6.5 Orientation / Unrolled Pipe

Provided that you are operating in a positive frequency regime, the circumferential orientation of anyreflected features can be determined. One way of determining the circumferential location of any defectis to separate the non-symmetric waves into their two orientations as described above in section 6.3.

A much more powerful method is to use the ’Unrolled Pipe Display’ analysis method that presents thecross sectional changes in a C-Scan style contour plot.

An example of this plot style is shown in figure 6.5. It was selected by changing the analysis protocol(shown in the ’Frequency Control’ box) to ’Unrolled Pipe Display’. Selecting this option causesWavemaker R© WaveProG3

TMto recalculate the processed data trace and change the top plot on the

display to be a contour plot showing the amplitude of the reflection as a function of linear distance andcircumferential angle.

To match the convention of displays of other types of inspection data, the bottom of the pipe (angle 180)is shown in the middle of the contour and the top of the pipe (angle 0) is shown at the top and bottomof the contour plot. Intermediate angles should be measured in a counter-clockwise direction if you arefacing in a positive direction and a clockwise direction if you are facing the negative direction. This angleconvention is shown for inflatable rings in figure 3.3 (page 17) and for solid rings in figure 4.2 (page 40).

Clicking on a point on the C-scan plot or on the main result trace shows a radial plot to right of theC-scan that represents the orientation and distribution of the cross section change at the selected axialdistance. This radial loss plot is shown as if you are facing in the positive direction. In figure 6.5, feature-F3 has been selected; the radial plot shows that the change is on the left hand side of the pipe (if wewere at the end of the pipe facing the ’positive’ direction of the ring). Feature, -F1 is on the bottom ofthe pipe, since it is in the middle of the contour plot.

Clicking on the contour plot also causes the main display trace (on the bottom) to show a cross sectionalong the length of the pipe at the selected circumferential orientation. This cross section results fromfocussing the energy at each position. Defects that are isolated around the circumference should appearlarger in this cross section view (as compared to welds and certain types of noise) than they do in the



6.6 Frequency Dependence 62

normal result trace (provided that the correct point around the circumference has been selected).

The display of the contour plot is affected by both the DAC curves and the contour options in theActions:Special:Adjust Contour Options menu dialog. Typically 18 dB of dynamic range is usedfor the color scale in the contour plot (this can be adjusted in the dialog). The top of the scale is alwaysset to match the height of the largest DAC that is currently active (usually the weld DAC). Therefore,adjusting the DAC curves (including feature dependent decays) is important to have a usable unrolledpipe display.

The analysis routine that is used to create the data for the unrolled pipe display is based on a focussingalgorithm. It combines information from several wave modes that are propagating in the pipe. A sidebenefit of this processing algorithm is that the signal to noise ratio of isolated defects is improved in somecircumstances.

The precision of the circumferential orientation of the feature will depend on the frequency regime ofthe inspection as well as the configuration of the ring. Higher frequency regimes are generally better.The circumferential resolution also improves at higher frequency regimes. However, the circumferentialresolution can never be smaller than size of one wiring segment in a ring. It is for this reason thatthe EFC style rings have more segments around the circumference. Their circumferential resolution istypically twice as good as a standard ring (resolving 45◦ circumferential extents as opposed to 90◦).However, features with circumferential extents much below this resolution value will typically look thesame in the unrolled pipe display.

Changing the analysis protocol back to another value (for example the default ’Interpolated Frequency’protocol) removes the contour (or C-Scan) plot.

Note 1. The unrolled pipe display uses significantly more memory and processing power than thenormal display; it will cause features such as the ’animated frequency display’ to updatemore slowly.

Note 2. The reported orientation of a defect is actually in relation to the ring. Therefore, it isimportant to ensure that the ring has been mounted on the ring in the correct manner toensure that the interpretation of the orientation is correct. The correct orientation is shownin figures 3.3 and 4.2.

Note 3. Double peaks appear in the orientation profile if there is a discrepancy on opposite sides ofthe pipe, for example if a weld is mis-aligned.

Note 4. Bends display an interesting pattern in this view; the paths through the ID and the OD ofthe bend tend to separate.

Note 5. The signal to noise of the reflection must be reasonably good for the orientation value to beaccurate.

Note 6. Early versions of WavemakerR© WaveProG3TM

did not have this ’focussing’ enabled. It isrecommended that you run at least release 93m.

6.6 Frequency Dependence

The behavior of suspicious echoes at different frequencies can help classify different pipe conditions (andespecially help identify supports). An efficient way of looking at the frequency effects is by clicking on the’Animate’ button on the ’Analysis’ tab. This button causes the results to continually sweep throughthe range of frequencies that were collected. The following guidelines can be given for how to interpretthe frequency changes:

• Reflections from good welds should change gradually and be visible at all frequencies for which theyare above the noise floor. Their shape should remain clean over the entire frequency range.



6.7 Phase 63

• Reflections from corrosion patches tend to vary in amplitude and shape as the frequency is variedif their length is greater than the transducer spacing.

• Increased amplitude of reflection (in comparison to a weld) as the frequency increases generallyindicates a

– defect that is localized along the length of the pipe (its predominant length is around thecircumference of the pipe), or a

– support that may have some corrosion associated with it.

• Decreased amplitude of reflection (in comparison to a weld) as the frequency increases generallyindicates a

– clamped or welded support,

– axial crack,

– area or heavy general corrosion before the location of the echo, or a

– wall loss for which the transition from a non-corroded pipe is spread over a long (greater than0.3m) length.

• Large attenuation change of subsequent echoes (i.e. subsequent echoes are much larger at lowfrequencies than at high frequencies) usually indicates

– heavy general wall loss with gradual change.

6.6.1 Bandwidth

In addition to changing the frequency regime of the displayed data, it is possible to change the bandwidthof the excitation signal by adjusting the slider near the ’bw:’ label. This adjustment has several uses:

Resolution Increasing the bandwidth improves the axial resolution of the displayed trace. This canoften help resolve closely spaced reflectors.

Unwanted Noise Ambient and modal noise often has distinct frequency bands that are best avoidedto make the data easier to interpret. By reducing the bandwidth (and adjusting the frequencyregime), it is often possible to avoid these bands.

Frequency Variation Decreasing the bandwidth makes the frequency dependence discussed above moreobvious.

Advanced Interpretation In many challenging applications, adjusting the bandwidth and frequencyregime can enhance the amplitude of the desired reflections as compared to the background noise.In some cases (when the attenuation is constant across a wide frequency range), increasing thebandwidth helps. In other cases (when there is highly frequency dependent attenuation caused byvisco-elastic coating or embedding media), decreasing the bandwidth helps.

Nice Looking Reports Often certain frequency/bandwidth combinations ’look better’ than others forreporting.

6.7 Phase

The phase of the reflected signal is different depending on whether the reflection is caused by an increaseor decrease in impedance (in our case, the impedance change is usually due to a change in the crosssection of the pipe).



6.7 Phase 64

Wavemaker R© WaveProG3TM

attempts to detect the phase of the reflected signal; it is displayed as a smallarrow on top of the ’feature icon’ bar. The actual phase that is displayed is not important, because itcan change depending on ’unimportant’ factors such as the type of coating. However, the relative phasebetween features is important. If several features have the same phase (their arrows point in roughlythe same direction), then it is very likely that they are all primarily either increases or decreases incross section. If all of the features except one are in the same direction, it is likely that the exception isdifferent.

This information can be very useful when examining echoes from interfaces. However, it is important tonote that there are some very serious limitations that mean that this information must never be usedalone (without collaborating information). The major limitations are that

Signal to Noise - The signal must be well clear of the noise floor (12 dB). Otherwise the phase can becorrupted.

Single Peak - The signal must be comprised of a single reflection. If there are multiple reflections withthe axial resolution of the analysis routines, they normally corrupt each other. (In other words, thepeak normally must be clean.)

Wide Bandwidth - The signal must be visible across a wide range of frequency bandwidths.

Straight Path - When the signal goes around a bend, its phase is changed. Therefore, all comparisonsmust be performed between reflection on the same straight length of pipe. (Some coating can alsoaffect the phase, but these are rare.)



Chapter 7

Level 1 Data Analysis

Interpretation of the data is most demanding portion of the guided wave testing. Diligent analysis andfeedback from follow up inspections is required for an operator to become more competent. It is importantthat the analysis is performed on site, so that follow up observations can be performed immediately.

Because the knowledge of the guided wave behavior used for interpreting the results can be quicklyforgotten, the GUL certified training scheme requires that the operators use the equipment frequentlyenough to keep their skills fresh.

This chapter gives an example process of how the analysis procedure could be carried out for a generic in-spection situation. Many specialized application areas, such as buried pipes, require special interpretationskills, which are beyond the scope of this document and are reserved for Level 2 inspector training.

This procedure is meant to give a basis from which specific (application specific) procedures can bederived.

Before starting interpretation, it is important that the data to be interpreted is of a good quality. Theequipment and data checks discussed in previous chapters are vital.

7.1 Interpretation overview

The rest of this chapter describes one possible strategy for analyzing results. It breaks the typical analysisprocedure of guided wave data into a series of steps:

• Identify weld and flange reflections

• Mark any embedded or coated sections

• Set the DAC curves

• Classify other reflections

• Determine the next required guided wave inspection locations or required retests using differentconfigurations

• Identify any required follow up

Many of these steps rely on a few basic interpretation principles that have been discussed in detail inchapter 6.



7.1 Interpretation overview 66

Control of displayed frequency bandwidthControl of displayed frequency regime

Adding Features

Mai

n R

esul

t Gra

phAu

xilia

ryG

raph

Dead zone in greenNear field in grey

DACCurves

Feature icons

Figure 7.1: An example ’Analysis’ screen.

7.1.1 Basic presentation of the data

An example of the ’Analyze’ screen can be seen in figure 7.1. The main portion of the screen is usuallyoccupied by a picture of the result trace. In this trace, the x-axis represents the distance away from thering. Positive directions represent items on the positive side of the ring (see figures 3.3 and 4.2). Thegreen and grey areas near zero distance represent the dead zone (where there is no valid data) and thenear field(where the data is corrupted). Reflections from within the near field can be analyzed, however,special care must be taken since amplitudes are artificially low and false echoes can appear.

The controls on the upper right determine how the processed data is shown. The default for theWavemaker R© WaveProG3

TMsoftware is ’Interpolated Frequency Analysis’, which allows the user to

dynamically change both the center frequency of the excitation and the bandwidth of the excitationby adjusting the scroll bars. The advantages of using different bandwidths and center frequencies arediscussed in section 6.6.


allows the user to mark the location of identified features with an appropriatesymbol on the pipe diagram that is displayed above the main graph. An example of this display in figure7.2.

Additional features can be added to this display by either

• Clicking on the feature toolbar (shown in figure 7.3) and then clicking on the pipe display or on apeak on the result trace.

• Choosing a type of feature from the feature pull-down, entering a distance, and clicking on the Add



7.1 Interpretation overview 67

Figure 7.2: Pipe diagram, showing features.

Figure 7.3: Pipe features toolbar.

button.

Features can be deleted by left clicking on the feature on the pipe diagram and choosing delete. Detailedparameters about a feature can also be set (as described in section 7.4.2).


makes use of various graphs to communicate information to the user. Thegraphs have a standard interface to permit the user to zoom into specific areas, make measurements etc.These features are accessed by positioning the mouse pointer over a graph and then right-clicking, whichwill cause a pop-up menu to appear. An item on the pop-up menu can be selected by clicking the mousepointer on it. All the items on the pop-up menu can also be accessed from the main menu and somemay be activated by pressing a particular shortcut key combination. The items on the pop-up menu areexplained below. If applicable, the shortcut key is given in parentheses.

• Zoom (F2) - this enables the user to zoom-in on a particular area of the graph. When this itemis selected, the mouse cursor will change to a magnifying glass. Click and drag the mouse to forma box around the area to zoom in on and then release the mouse button.

• Pointer (F5) - this enables the user to get details of a particular point on a graph. To do this,position the mouse pointer near the point of interest and click. The pointer will change to a crossand move to the nearest point a the graph. Details about this point will then be displayed in thestatus bar of the main Wavemaker R© WaveProG3

TMwindow and also above the graph. Moving the

mouse with button held down will move the cursor along the graph.

• Measure (F11) - this enables the distance between two points on a graph (in terms of the x andy co-ordinates) to be measured quickly. To use Measure, click and hold on the first point and thendrag the mouse to the second point. The measurement is displayed above the graph and in thestatus bar of the main Wavemaker R© WaveProG3

TMwindow.



7.2 Identify welds 68

Table 7.1: Example of how the interpretation skills apply to welds and flanges.Tool Weld FlangeExpectations Usually regularly spaced; Not

more than 13m apartNormally not buried; insula-tion usually must change shapearound a flange

Visual Likely visible if not insulated,ground off, or buried

Should be visible

Amplitude Should be above noise floor Often largest reflectionSymmetry Symmetric SymmetricShape Single, clean echo Typically, a rough, irregular

echoFrequency Should be consistent in shape

and amplitude across a wide fre-quency bandwidth

Shape and amplitude maychange with frequency

Phase Should be same as other ’welds’

• Actions - clicking on this item brings up a sub-menu with various options relating to copying thedata in the graph onto the clipboard to transfer them to another application.

• Autoscale (F4) - clicking on this item re-scales the graph so that all the data points are displayed.Shift-F4 causes only the Y axis to be automatically scaled.

A zoom feature that is only accessible from the main menu enables a precise area (as specified by itsco-ordinates) to be viewed. This feature is accessed by selecting View:Custom Zoom.

7.2 Identify welds

The initial portion of the interpretation of the processed data concentrates on identifying the echoesfrom known (i.e. visible) features and easily interpreted, expected features. At this point, we are notinterested in classifying corrosion. The main goal is to identify reflections that allow us to estimate therate of attenuation of the signal as it propagates down the pipe. The following steps should be followed

Identify visually observable features such as flanges, bends, and welds. Mark these as features.Some welds may have been automatically marked by the software, if these are not welds then thefeature marks should be deleted or changed to represent what the features actually are.

Identify (non-visible) welds and flanges Table 7.1 describes how the basic interpretation tools re-late to weld and flange reflections. Figure 7.4 shows the reflection from some typical weld and flangeechoes.

Note 1. On longitudinally or spiral welded pipe all weld reflections will contain some non-symmetriccomponents.

Note 2. Defects may be found at welds; in this case, two features should be placed at the samelocation, one for the weld and one for the defect.

7.3 Mark any embedded sections

This inspection technique is often used to screen the condition of a pipe as it passes through a buriedsection. These locations should be accurately marked on the iconic drawing so that the relative locationof identified features can be easily extracted.



7.4 Set the DAC curves 69

-10.0-10.0 -5.0-5.0 0.00.0 5.05.0

1.01.0

2.02.0

3.03.0

Distance (m)

Amp (mV)Am

p (m

V)

+F1+F1 +F2+F2 +F3+F3 +F4+F4-F1-F1-F2-F2-F3-F3-F4-F4

Too much redto be a weld

Many welds together(a pair of welded bends)

Irregular shape(welded support)

Irregular shape,Large amplitude

(Flange)

Regular shape,symmetric

regular size(classic welds)

Figure 7.4: An example trace highlighting feature characteristics.

If the pipe is wrapped in a thick coating such as bitumen or denso tape, the ultrasonic signal will beheavily damped within this wrapped section. Therefore, the beginning and end of the wrapped sectionsshould be marked on the trace so that the DAC curves can be adjusted to compensate for the extraattenuation that will be experienced. It is important to enter in what type of coating the entrance isdefined for (by clicking on the feature and choosing the type of coating from the drop down menu).

The best way to specify the length of embedded or coated section is to open the feature properties dialog(left click on the icon of the feature and choose Properties) and directly enter the feature length in theto space marked ’length’. Alternatively, the end of an embedded section can be specified by inserting anexit feature at the end of the section (in some releases of software). The feature properties dialog alsoallows the inspector to adjust the decay levels associated with a given feature (as described in section7.4.2).

Multiple embedded or coated sections can be defined for the same trace. Therefore, it is possible tospecify both a wrapping start as well as the entrance into another feature (such as a wall).

7.4 Set the DAC curves

In order to be able to compare the amplitude of any reflections and use certain interpretation tools, it isnecessary to set the DAC (Distance Amplitude Correction) surfaces. Periodic reference reflectors, suchas welds, are typically used to determining this decay, however more complicated methods are availablewhen weld reflections are not available. More detail about the DAC curves is given in section 6.2.1 onpage 53.

7.4.1 Automatic DAC Fit

The easiest way to set the DAC surfaces is to Choose Configure:Auto-Fit DAC:To Welds once aseries of welds has been identified and marked on the pipe diagram. If there are less than 2 welds in thetrace, then the option Configure:Auto-Fit DAC:To Features or Configure:Auto-Fit DAC:FromCalibration should be used. This operation should calculate a best fit surface across a wide frequencyrange. The results of the fit can be observed over this range by moving the interpolated frequency scrollbar (shown in figure 7.1).



7.4 Set the DAC curves 70

Figure 7.5: The Feature Properties dialog.

Note 1. The weld positions must be marked accurately on the peaks for accurate results.

If the automatic fit of DAC curves does not appear to be correct, the effects of the different types ofdecay can be separately adjusted in the Configure:DAC Levels dialog. This dialog, shown in figure6.1, allows the default drop due to welds or other features to be adjusted to better match the particularpipe being tested. Once these overall levels have been adjusted, the DACs can be refitted.

7.4.2 Feature Dependent Decay

In addition to adjusting the overall decay for a type of feature, it is possible to adjust the drop or decaylevel of any single feature. This option appears in the ’Feature Detail’ dialog shown in figure 7.5. It isaccessed by clicking on the feature and selecting Properties from the drop down menu or by doubleclicking on a feature entry in the ’Report’ tab. The four attenuation levels control the decay. All of thevalues that you enter for a specific feature are added to the default value for that type of feature (which isshown to the right, if it is not zero). Entering a negative number increases the decay; a positive numberincreases the amplitude. These levels can be described as

• dB This is a straight drop (in dB) that is applied at all frequencies.

• dB/m If a length is defined for the feature, this amount of decay will be applied for the length ofthe feature. There will typically be a default value defined for coating type features.

• dB/kHz This is a frequency drop that is frequency dependent. For example, the default value forthis parameter for a weld is -0.05. This means that there will be a 0.5 dB drop in amplitude for a10 kHz signal and a 2 dB drop for a 40 kHz signal.

• dB/(kHz-m) This is a frequency dependent rate of decay. It sets how the distance decay rate (fora feature with a length) will increase as the frequency increases.

The overall decay can be manually adjusted via a mouse action by selecting the Edit:Stretch DACsmenu item. Clicking and dragging a DAC curve will cause it to change position. This action will needto be repeated at one other frequency in order to adjust the entire DAC surface.



7.5 Classify other reflections 71

Other methods

There are several other methods that can be used to set DAC curves when several feature echoes are notavailable. These methods (which are covered in level 2 training), include:

Remote ring - Using a second, remotely located, ring (potentially connected to a second G3 unit) asan additional receiver. By observing the amplitude of the outgoing wave at a remote location, theheight of the DAC at that remote location can be determined.

Reference reflector - If there are no reflectors that can be used for reference, a pipe clamp can beplaced on the pipe to provide a reflection. The size of reflection generated needs to be calibratedon a similar, section of pipe on which the DAC curves are known (for all frequency regimes thatwill be used).

Copy and paste - If solid rings are used or inflatable rings are always used at the same pressure,the initial transmitted amplitude can often be assumed, based on the output amplitude from adifferent location (provided that all of the conditions (such as paint type) and configuration (suchas frequency) are the same.

7.4.3 Determining end of test

The height of the DAC curves in relation to the random (ambient and electrical) noise floor allows therange of the test to be evaluated. The reported range of the test will depend on the required sensitivity.A realistic example case is shown in figure 7.6. The result is shown on a log scale because it is oftennecessary to show more dynamic range than can be viewed on a linear scale. A horizontal line has beendrawn across the tops of the peaks of the random noise. This ’noise floor’ is compared to the DAC curves(which appear as straight lines on a log scale). Using the principle that a peak must be 6 dB greaterthan the noise floor to be reliably detected, one is able to determine at which points certain defects arelikely to be detected. For example, the noise DAC (representing 5 percent amplitude) crosses the noisefloor at -15m. Therefore, beyond this point a 10 percent defect could be missed, however, a 20 percentdefect should be reliably picked up. In this example, the weld at -17m (about a 20 percent reflector) canbe identified easily, however the confidence of detecting the small defect at -16m is low. Beyond about-19m, the detection of a 20 percent CSC defect is no longer likely.

7.4.4 Save results

It is recommended that the results are saved frequently, just in case the software crashes.

7.5 Classify other reflections

The end of the inspected test range can be set once the DAC curves have been adjusted. In general, theend of the test range corresponds with the point where the total noise floor is more than half the heightfrom zero to the call DAC. However, the declared position of the end of the test range depends on therequired minimum level of defect that must be detected.

Many performance related parameters are heavily dependent on the general condition of the pipe. Theseinclude items such as the overall test range that can be expected as well as the call level. On a pipethat is very clean, corrosion or any other type of defect much smaller than 10 percent of the pipe wallcross sectional area could be identified. However, on a pipe that generally corroded, it may be difficult tolocate areas of more severe corrosion unless they correspond to a much higher percentage loss then thenormal call level of 10 percent.




-30-30 -20-20 -10-10 00

1.21.211

0.50.5

0.250.25

0.10.1

0.050.05

0.0250.025

0.010.01

0.0050.005

0.00250.0025

Distance (m)

Amp (mV)Am

p (L

og s

cale

)

Electrical noise flooris linear

Once the noise 'Noise'DAC reaches theelectrical noise floor,a call size defect can notbe reliably detected.However, larger defectscan still be detected

10%

det

ecta

bilit

y lim

itFigure 7.6: An example of how the end of test range (for a given sensitivity) is determined.

Once the general condition of the pipe is noted, the reportable levels may need to be adjusted accordingly(to avoid classifying the entire pipe as defective). The exact actions to take depend on the reportingprocedures that are in place.

7.5.1 Examine other features

At this point, reflections from features such as welds and flanges should have already been identified. Itis now time to begin classifying the other features that appear on the processed trace. For each of thereflections that is above the reporting level (or 3db above the general noise floor), the following stepsshould be completed.

Attempt initial classification of support / minor / severe. This classification should take account ofall of the tools that were listed in table 6.1, including expectations, size, shape, and symmetry. Mostof the features that need to be classified at this point in the analysis procedure should have havelarge non-symmetric components (if operating in a positive frequency regime). A more detaileddescription of how to categorize the circumferential extent of reflections is given in section 6.3.

Mark all these suspicious features with a ? mark (an unknown feature).

Attempt to match supports with ISO drawing or observations to see if these echoes correspond withsupports. If the supports are welded to the pipe, echoes at the weld call level should be inspected.If the supports are clamped, the size of the echo will depend on the tightness of the clamp. If thepipe simply rests on supports, the echo from the supports is usually below the call DAC if thereare no defects present. The frequency behavior of all supports should be examined as described insection 6.6.

Apply Analysis Tools Chapter 6 lists a series of tools that can be applied to analyze specific reflections.These should be applied to all suspicious echoes to aid classification.




7.5.2 Check for False Echoes

When screening a pipe, the most important consideration is that no areas of reportable corrosion aremissed. However, from a commercial point of view, it is also very important that false calls are minimized(especially when access to the pipe for follow-up inspection is difficult).

When analyzing the results, the operator should always be mindful of the possibility of false echoes.There are four main types of false echoes of concern.

Noise spikes - Ambient noise in the pipe or noise injected through invertors can often show up in theprocessed results. It is important to use the tools mentioned in previous sections to separate signalsfrom noise and set the test range appropriately.

Mirroring - When the direction of the transmitted and received wave is not adequately controlledleading to a small ’echo’ in the ’wrong’ directions.

Reverberation - When the energy reverberates between two large features making it appear that thereis a small third feature beyond the second feature.

Modal noise - When the ring is not able to control all of the wave modes that are propagating in thepipe.

Mirroring

When the direction of the transmitted and received wave is not adequately controlled, a small copy of areflection can appear in the ’wrong’ direction. This normally only happens:

• Within the near field

• If there is a major fault with the system

• If the reflection is ’noise’ (either incoherent or modal)

• If the wrong module spacing is chosen

The easiest way to detect mirroring is to use the ’Stacked’ plot option (View:Processed Data:Stacked),which separates the positive and negative direction into two different plots. If there is a large feature inone direction and a small feature at the exact same distance from the ring but in the other direction,then the operator should suspect that a mirror could be possible.

An example of a mirrored reflection is shown in figure 7.7. The reflection in the near field at 0.8m fromthe ring is at the same location as the first part of the main flange reflection at -0.8m. Since this reflectionis within the near field and at the same absolute distance, a false mirrored reflection is suspected.

The best way to determine if a reflection is a mirror is to change the position of ring by at least 0.6m(2 feet) and retest with the same parameters. If the reflection is a mirror, the corresponding position onthe pipe where the false echo appears will change as the test position changes.

Many of the guidelines for choosing test positions are recommended to reduce mirroring. GUL recom-mends that you do not test from a position in the middle of two large features, in order to ensure that nomirroring is taking place. In addition, GUL recommend that whenever possible the test position shouldbe well away from (or very close to) large features. If a large feature is within the near field (but outsidethe dead zone), a small copy will falsely appear on the ’wrong’ side of the ring. This can lead to false callsor unnecessary follow-up inspection. Please note that the dead zone and near field are usually shown onthe processed data trace as green and grey sections. If they do not appear, they can be turned on viathe File:Print Options dialog.




0.00.0 1.01.0 2.02.0 3.03.0 4.04.00.00.02.02.04.04.06.06.08.08.010.010.012.012.0


Backward (mV)Bac

kwar

d (m

V)

0.00.0 1.01.0 2.02.0 3.03.0 4.04.00.00.02.02.04.04.06.06.08.08.010.010.012.012.0

Forward (mV)Forw

ard

(mV)

+F1+F1 +F2+F2-F1-F1

Figure 7.7: An example of stacked plot helping to identify a mirror.

Reverberations

Whenever a wave is reflected back to the ring, it does not stop at the ring, but continues under the ring.It is free to reflect from features in the other direction and return back to the ring (where it can bedetected). These multiple echoes are referred to as reverberations and are very similar to seeing multipleback wall echoes in conventional UT inspection. Figure 7.8 shows the wave paths and how they appearin the results. The positive direction that is displayed in Wavemaker R© WaveProG3

TMcorresponds to

any waves that leave the ring traveling to the right and return to the ring from the right (Other directioncombinations are either ignored or appear as ’negative’). In the example in figure 7.8a, the main signalgoes out to the right reflects from the weld, passes back under the ring, reflects off a flange in the oppositedirection, passes back under the ring, reflects off the weld on the right for a second time, comes back tothe ring, reflects off of the flange, passes back under the ring, and so on for infinity. Any of time that thewave is coming from the right, the software will display the echo in the positive direction. Therefore, afalse echo will appear in the results at the location specified in figure 7.8b.

These reverberations are normally too small to be seen in the guided wave results. This is best illustratedby a numerical example. If both the left and right features are 25 percent amplitude (6.25 percentenergy) reflectors, the amplitude of the first reverberation signal would correspond to about a 1.5 percentreflector. This size signal is usually lost in the noise (especially because many welds are actually 10percent amplitude reflectors, which means that the reverberation amplitude would only be 0.1 percent).

The situations when the reverberations become important is when there are large features (that reflectmore than 25 percent of the amplitude) on either side of the ring. This is the case in the example shownin figure 7.9. On the left there is a flange and on the right both a weld and a welded annular ring (whichis a large reflector - about 50 percent amplitude). The wave reverberates between these two features andthe first two reverberation echoes can easily be seen on the trace. The distances r1, r2, and r3 are allthe same and correspond to the distance between the two features.




Flange

Flange

Weld

Weld

Ring

Ring?

ImaginaryFeature

Flange

Flange

Weld

Weld

Ring

Ring?

ImaginaryFeature

a) What actually happens

b) What it appears like in the result

c) What happens when the ring position is moved slightly

Figure 7.8: A diagram showing the wave paths for a reverberation and how it is processed in the results.




-5.0-5.0 0.00.0 5.05.0 10.010.00.00.0

1.01.0

2.02.0

3.03.0

Distance (m)

Amp (mV)Am

p (m

V)

+F1+F1 +F2+F2 +F3

+F4+F4-F1-F1

Mirror

Firs

t rev

erbe

ratio

n

Seco

nd re

verb

erat

ion

Reflection from largeannular ring

r1 r2

m1 m2

r3

Figure 7.9: An example trace that shows multiple equally spaced reverberations (r1, r2, and r3) as wellas a small mirror (equally spaced around the origin as a real feature (m1=m2).

The shape of the reverberation signal depends on the reflection shapes of the two features. If both of thefeatures were clean welds, the reverberation would also look like a clean weld. However, in the case oneof the features is actually a double feature (a weld and the welded ring) so the two peaks become 4 peaksfor the first reverberation and 6 peaks for the second reverberation.

In order to confirm that an echo is a reverberation, it is best to change the test position so that ring isno longer between the two large features. In this example, the best location would be to the right of theannular ring. If it is not possible to move to a such a location, then a configuration should be chosen thatminimizes the size of the reflection from the features. This is often done by either raising or lowering thefrequency (depending on what type of feature it is). In extreme cases, a visco-elastic wrapping could beadded to the pipe on one side of the ring to help reduce the amplitude of the reverberations.

Please note that the procedure of moving the ring a few feet but still within the same length of pipe (thathelps distinguish mirrors) will not help distinguish reverberations. A graphical explanation of why thisis true can be seen if figure 7.8c.

Modal noise

The Wavemaker screening system has been designed to operate over a wide range of frequencies and pipewall thicknesses. However, there are some extreme cases that exceed the default parameters. Many ofthese cases relate to the physics of what wave modes can exist in the pipe. The most common cases are

• Very thin pipes (the thickness less than 1 percent of the radius)

• Very thick pipes (the thickness greater than 30 percent of the radius)

• Testing on top of a delamination



7.6 Perform test from other side 77

-20-20 -10-10 00 1010 20200.00.0

0.20.2

0.40.4

0.60.6

0.80.8

1.01.0


Amp (mV)Am

p (m

V)

Figure 7.10: An example trace that shows the effects of severe modal noise.

• Testing beyond the normal frequency ranges

When these modal problems occur, the results often look like the result shown in figure 7.10. In someother cases, one of the traces (either black or red) can ’lift’ off from the zero axis. Reducing the frequencyand bandwidth and adjusting the frequency regime can often hide these problems.

7.6 Perform test from other side

Whenever possible, inspections should be conducted from both sides of suspicious areas. This helpscorrectly estimate the severity of the reflection if the corrosion patch is shaped so that the transitionfrom good pipe is very sharp on one side (i.e. easy to find) and very gradual on the other side (i.e. muchmore difficult to find). If a difference is found between the tests from the two directions, the worst case(i.e. most corrosion) should always be taken.

Examining the pipe from both sides is especially important when inspecting road crossings or whenexamining a feature that appears in a bend (which may look different from the two sides, dependingwhere the feature lies in relation to the two welds on either side of the bend).

The overlay capabilities of the Wavemaker R© WaveProG3TM

software facilitate the comparison of datafrom different test locations.



7.7 Classification of echoes 78

7.7 Classification of echoes

After examining the circumferential symmetry and the frequency effects of the suspicious echoes a clas-sification should be assigned by placing the appropriate icon at the corresponding position on the pipediagram that appears above the processed trace.

7.7.1 Corrosion classifications

Suspected corrosion can be classified as one of three categories

Category 3 - Minor (below reporting threashold) . This level of corrosion is appropriate whenboth the black (symmetric) trace and the red (non-symmetric) trace are below the call DAC. Itshould correlate with corrosion for which less than 10 percent of the cross sectional area has beenlost. These indications are usually marked for information on pipes in good general condition.

Category 2 - Minor/Medium corrosion . This level of corrosion is appropriate when the black traceis between the call DAC and the weld DAC, but the red trace remains below the call DAC. It shouldcorrelate with greater than 10 percent cross sectional area loss that is distributed in a manner thatwill typically remove less than 50% of the wall thickness.

Category 1 - Severe corrosion . This level of corrosion is appropriate when both the black and redtraces are above the call DAC. It should correlate with a defect that has a strong possibility ofpenetrating more than 50% of the pipe wall thickness.

Notes that are specific to a certain feature (for example their estimated depth) can be added in the reporttab screen. Whenever possible, it is recommended that immediate follow-up inspection of these suspectareas is conducted. The results can be added into the notes. There are also specified fields in the featureproperties for items such as the measured wall loss. If you are not sure about the classification of afeature, please document this in the notes.

7.7.2 Review of terms

The past analysis steps discussed several terms that are used to describe a reflection and help classify it.A summary of these terms follows.

CSC - Cross-Sectional area Change. What percentage of the total cross section of the pipe has changedat any given axial position.

ECL - Estimated Cross sectional Loss. An estimate of what percentage of the cross section has beenlost. (Frequently used inter-changeably with CSC).

Circumferential Extent - refers to how the change in cross section is distributed around the pipe’scircumference. Is it evenly distributed or clumped together? This is normally expressed as apercentage of the total circumference. Small extents are localized patches; large extents are generalchanges.

Symmetry - Is the change in cross section section symmetrically distributed are around the circumfer-ence of the pipe. Echoes with a large circumferential extent are considered to be symmetric, thosewith a small extent are considered non-symmetric. Note that the symmetry has no implicationabout the shape of the corrosion in the axial direction.

Orientation - At what circumferential orientation is the center of average cross sectional change.



7.8 Make overall notes 79

Shape - Does the reflection have a clean shape (indicating that it is short axially) or is it irregular(indicating that is has some length along the axis of the pipe).

Wall Loss - The percentage of the pipe wall that has been affected by a feature. This parameter cannotbe directly measured by this screening technique; ranges of wall loss could be estimated, but therewould be large error margins. Therefore, complementary techniques are typically used to providethis information.

7.8 Make overall notes

General notes about the specific features of the pipe can be added on the ’Report’ tab screen. It is oftenimportant to note items such as,

• Condition and type of pipe, coating, and supports

• Action that should be taken (OK, minor concern, major concern, monitor regularly),

• Confidence in results (High / medium / low / invalid data),

• Where the pipe is.

Much of the general information about the location and surface condition of the pipe can be enteredinto the appropriate space on the collect screen while the raw data is being collected. Please rememberthat this information is essential for the correct interpretation of the results. The taking of notes anddocumenting the interpretation must be undertaken with care and due diligence. Unless the resultsare written down, interpretation results that are clear at the time are soon forgotten as other tests areperformed.

Reporting, which is discussed in the next chapter, often takes as long as data collection and analysis.

7.9 Identify any required follow up

The guided wave results on their own will never be able to robustly provide a reliable measurementof wall loss. Therefore it is important to plan follow-up inspections on any suspect areas. It is highlyrecommended that the follow-up inspection is performed immediately by the same team that is performingthe guided wave inspection. This immediate follow up helps reinforce the interpretation skills of theoperator. In addition, it provides motivation for a detailed search to find the defects associated withsuspicious areas. On many occasions the guided wave results have shown indications in areas thatinitially appeared clean with manual UT inspection. However, increasing the frequency of the UT probeand decreasing its diameter allowed a detailed follow-up scan to reveal sharp irregularly shaped corrosionareas typical of bacterial attack.

7.10 Move to next test location and repeat

The length of pipe that was reliably inspected should be known from examining the DAC curves. Thisinformation, along with the layout of the pipe, can be used to determine an appropriate location for thenext test.

Please ensure that you save the result file before moving onto the next test location and entering newsite information.



7.10 Move to next test location and repeat 80

Each inspector should keep a log of what tests they perform. These logs are used for revalidation in theGUL compliant training scheme that is described in Appendix D. Some example logs are given in theLevel 1 inspector training pack. The procedure for updating the count of tests performed by an inspector(that is held on the inspector key) is given in section 3.6.4.



Chapter 8

Reporting Results

Accurate reporting of guided wave results is extremely important. Often overlooked when schedulinga job, the reporting process usually takes as long as the data collection and analysis. (Any specialreporting requirements should be identified at the time that the scope of the work is being established).It is important that good follow-up inspections, photographs (if allowed on site), and observations aremade throughout the inspection progress.

Reporting the results often involves skills that are separate from the analysis of the guided wave data.Ideally, the guided wave results are combined with follow-up inspections, structural analysis, and historiesof the line, to provide an end-client with a full assessment of the condition of the area inspected.

This chapter presents an overview of how the Wavemaker R© WaveProG3TM

software can be used to helporganize and present the guided wave data.

8.1 Overview

The reporting functions are divided among three tabs in the Wavemaker R© WaveProG3TM

software:

’Report’ Used to record analysis information from a test and control how a single test will print.

’Images’ Used to attach JPEG images from other sources to supplement the guided wave data.

’Summary’ Used to organize a series of tests, decide which tests to include in a report, and searchresults.

8.2 The report screen

A screen shot of the ’Report’ tab can be seen in figure 8.1. The screen is divided into several sections.From the top to the bottom of the page:

• Summary Information As part of the data analysis procedure, the operator should assign ageneral classification to the result as well as a confidence level of that classification (and the defectcalls that were made). Once the analysis has been completed, the ’Operator Verified’ buttonshould be clicked to approve the results for reporting.



8.2 The report screen 82

Figure 8.1: An example ’Report’ screen.

• General Information This information reflects the collection parameters that were defined at thetime of the test. (Changes to these items are made by changing the relevant fields on the ’Collect’tab and then clicking on the ’Change Saved Site’ button.)

• Report Notes These notes will appear as ’General Notes’ on the printed report page. A copy ofthe same notes appears on the ’Collect’ tab.

• Feature List A table is created summarizing information about each of the features that havebeen defined for the test result. This table allows the values to be manipulated and modified.Clicking once to highlight a feature and then a second time on a specific item will allow mostitems to be changed. Alternatively, double clicking (quickly) on a feature row will bring up theFeature Detail dialog that allows most values to be changed. Table 8.1 describes the meaningof the various columns. The choice of which columns to print on the final report is made in theActions:Summary:Choose Report Columns dialog.

• Result graph The graph that will appear on the final report is shown on the bottom of the screen.The format of this graph will depend on which File:Print Options are selected. The frequencyand range that are displayed match those that were last displayed on the ’Analyze’ tab screen.

8.2.1 Print options

How the report will be printed is mainly controlled by the File:Print Options dialog. A view of thisdialog is shown in figure 8.2. This dialog has several areas, including

Summary , which affects how the ’Summary’ tab prints; it will be discussed in section 8.4.

Logo , which affects if and how the logo will be printed; each of the items is described in table 8.2.




Table 8.1: Descriptions of the feature information columns.Item DescriptionP This determines whether or not a feature will be printed on the report. If there is a

P in this box then the details of the feature will be printed on the report. If P is notshown, then although the feature will still be marked on the pipe diagram, it willnot be labeled or identified. To change this option, click once on the box to togglewhether or not P is displayed in it.

Feature The feature label. The features are automatically named depending on their positionfrom the ring. However, the label for the feature can be manually changed in theFeature Detail dialog.

Location The distance of the feature from the transducer ring (positive values represent thepositive side of the ring). This value can be adjusted by clicking on the box and thentyping a new value. The icon on the pipe diagram will move appropriately. Pleasenote that if the zero point has been moved to a fixed datum (via Actions:CalibrateDistance), the values printed here have that fixed datum value added.

Size The amplitude of the signal from the feature in mV. This value is automaticallyextracted from the signal trace.

ECL (esti-mated crosssectional loss)

This is the estimated change in cross section of the feature. This value is calculated bycomparing the amplitude of the signal from the feature to a reference level obtainedfrom the DAC curves and then using a look-up table to relate this to the loss ofcross sectional area. The values in the look-up table have been computed using finiteelement (FE) analysis. The value can be overridden if an experienced operator wouldlike to enter the worst case scenario (across all frequencies) instead of the value atthe currently displayed frequency.

Length This is the length associated with a feature. This value is mainly used for coatings,embedded sections, and corrosion patches. It can affect how the DAC surfaces areadapted for local attenuations.

M This flag should be used to mark whether the Wall (in the next column) has beenmeasured directly using another technique ((M) present) or whether it has beenguessed to help clarify the results (M not present).

Wall This column allows the measured wall at a defect location to be entered. It isused to help record the results of follow-up inspections and to perform advancedplotting functions. (Please note that the units for this value are controlled by theView:Preferences dialog.)

Extent This is the estimated circumferential extent of a feature. It is automatically cal-culated by comparing the amplitude of the reflections of the different guided wavemodes. The value will only be valid if the results are for a positive frequency regime.

Class this is the classification of the feature. To change a classification, click on it andselect a new classification from the pull-down box which will appear.

Longitude The Feature Detail dialog allows the position of specific features to be entered (ifan external differential GPS unit is connected). If the position is defined, it can beprinted with the report (although it will not appear on the ’Report’ tab).

Latitude Please see the description for Longitude.Phase This is the approximate phase of the reflected signal at the feature (reported in

degrees).Notes This column contains any notes that the user wishes to enter concerning that feature,

as described below. To enter notes, click on the appropriate box. The box will becomehighlighted and text may be entered or edited.




Figure 8.2: The File:Print Options dialog.

Reports , which controls the exact formatting of the reports. Please refer to tables 8.3 and 8.4 for adescription of each parameter.

Header/Footers , which add text to the top and the bottom of the printed or exported pages. In theheader / footer strings there are three pairs of brackets. Any text entered in the first set will be leftjustified, that entered in the middle set will be centered, and that entered in the right set will beright justified on the page. Special codes, such as <Page >can be inserted via the ’Insert’ pull-downbox. The ’Initial page number’ is used to provide a page offset for all of the page numbers that areprinted by Wavemaker R© WaveProG3

TM.

Note 1. The font that is used for printing is controlled by the View:Preferences dialog.

Note 2. Usually only a portion of the collected data range will contain meaningful data. An efficientway of truncating the remaining data is to choose Actions:Special:Truncate Data, whichallows the positive and negative distance limits to be set.

8.2.2 View Preferences

Several other display options are controlled by the View:Preferences dialog box. These include itemssuch as the units, language, and fonts used for displaying and reporting data. An example of the dialogis shown in figure 8.3.

Some items that may not be clear as described below

Input Length Units This is the default unit that will be used in fields that require axial lengths alongthe pipe.

Input Wall Units This is the default unit that will be used for wall thicknesses (in the report tableand for the default pipe thickness on the collect screen).




Table 8.2: Descriptions of the logo formatting fields.Item DescriptionPrint Logo If checked, a logo will be printed on all report printed pages.Leave Space If a logo is not being printed (see above), checking leave space will force Wavemaker R©

WaveProG3TM

to leave enough space at the top of the page for the pages to be printedon most company letterhead.

Import File If not checked, Wavemaker R© WaveProG3TM

will print its own internal logos (Thecurrently attached licence key will control which logo will be selected). If checked,Wavemaker R© WaveProG3

TMtry to import the file that is specified in ’Browse Import’

Alignment When a logo is being imported, this pull-down specifies where the logo should beplaced on the page.

Size When a logo is being imported, this pull-down specifies whether the default spaceinto which the logo is scaled should be expanded or reduced.

Browse Import Click on this button to specify which logo to import. It is recommended that a highquality JPEG image is used. (Please note that the JPEG2000 lossless image formatis not currently supported). An enhanced metafile (*.emf) can also be specified,however, emf files will only affect printing (not exporting the data).

Table 8.3: Descriptions of the report formatting fields.Item DescriptionUse Alt Defect Name Use names such as Cat1, Cat 2, and Cat 3 instead of minor, medium, and

severe.Do not print pipe condi-tion

Do not include the extra pipe information fields such as coating, type ofsupport, observed corrosion, when printing the report.

Do not print Verified by Skip printing the signature line on the bottom of the report.Do not print Warnings Skip printing General Warnings on the report screen.Include File in Header Prints the filename when printing the report.Include Test ID inHeader

Prints the psuedo-unique test ID in the header of the report.

Include Result in Header Prints the operator assigned overall result in the header of the printedresult.

Print report as two pages When checked, divides the printed report into two pages. The first pageincludes the header and the result graph; the second pages contains thefeature information table.

Show Near Field Controls whether the Green and grey shaded areas indicating the deadzone and near field of the test are shown on the result plots.

Rotate Labels Rotates and shrinks the feature labels on the result graph to allow longerfeature names to be used.




Table 8.4: Descriptions of the report option fields.Item DescriptionScale Operators can choose to print the result on either a linear or log scale.Range When printing on a log scale, the Range box controls the dynamic range

that will be displayed.Units Controls what units are used for the X-axis scale.Language Which language’s labels should be used for the printed report. Please note

that changing the language (for example to American) can automaticallychange the Units and export paper size when the dialog is closed.

Export Paper Size When exporting to a pdf document, what size of paper should be used?(Please note that the paper size for printing is controlled by the File:PrintSetup dialog.

Graph Style (Normal) This field determines how the result will be printed before it has beenverified by the operator performing the analysis.

Graph Style (Verified) This field determines how the result will be printed after it has been verifiedby the operator performing the analysis. A description of the possibleformats is provided in table 8.5.

Table 8.5: Descriptions of the report graph formats.Item DescriptionResult trace This is the default, it shows a pseudo A-Scan view of the results. The X

axis is the distance from the ring (or defined datum) and the Y axis is theamplitude of the reflection.

Cross Section Change This option uses the currently defined DAC curves and the current selecteddisplay frequency to calculate the estimated cross sectional area change.The cross sectional area change is then plotted as an increase for certaintypes of features or a decrease for other types of defects. The cross sectionalarea change that is used for each feature (as well as the length of thatfeature) can be controlled by the ’Feature Detail’ dialog. This displaymethod will be automatically blocked if the software thinks that theremay be a problem with the raw data or the DAC curves.

Measured Wall This display option will plot a wall thickness as a function of distance.Since the guided wave results cannot provide wall thickness measurements,these wall thicknesses must be provided for every defect like feature (viathe M and Wall columns of the feature information.) In addition, thenominal pipe wall thickness must be specified in the ’Collect’ tab. Thisoption should only be used if extensive follow-up has been performed. Itwill be blocked by the software if any collection faults are reported. Itwill be removed from future releases of the software if it is being usedincorrectly.

Leave Blank Do not print any graph on the report pages.Images Print any attached images in the space (on the report page) that is normally

used for the result graph.




Figure 8.3: The View:Preferences dialog in Wavemaker R© WaveProG3TM

.

Report Language This is the language that is used for the headers and feature names in the report(as well as the menu items for some languages). If you would like to request a language that isnot currently included, please contact [email protected]. This field is also used toset certain hidden defaults like the default paper size and the format of the date. These differencesrequire the separation between ’British’, ’American’, and ’Neutral’ (the built in English defaults).

Report Units These are the units that should be used for drawing the graphs of the results. Thesefrequently match the Input Length Units, however, they can be different.

GPS Display This field describes how the GPS position (if defined) should be displayed. Both angular(WGS84) and cartesian (UTM) coordinate systems are supported.

Save client name as a directory level When checked, this field causes Wavemaker R© WaveProG3TM

to create an additional level of directories between Results and the name of the Site. The currentclient name can be changed by choosing Configure:Operator.

Filename Format The automatically generated filename for a test can have different formats. Thedefault is to use the pipe, datum, and distance fields from the ’Collect’ screen. However, a shortversion that only includes the serial number of the instrument and the test ID number can also beused.

File Optimization This field control how the data is stored to disk. Two choices are available, optimizefor fast processing (so that frequency sweeping can be performed more quickly) or optimize for size(which then requires more recalculation before the frequency regime can be changed).

Display Font This is the font used for displaying the data on the ’Report’ screen.

Printing Font This is the font that used when the report is printed when the characters fall into thestandard western Europe character set.

Japan Font The font used if Hiragana or Katakana characters are detected.



8.3 The images screen 88

Other Font The font used if Kanjii or unrecognized characters are found.

8.3 The images screen

Photographs can often significantly help make the report more clear and interesting to read. They canalso be used to help document external corrosion or test locations. For these reasons, the new versionsof Wavemaker R© WaveProG3

TMallow JPEG images to be easily imported, embedded, and printed. In

order to add an image to the result, use Windows Explorer to click and drag the image file into theWavemaker R© WaveProG3

TMwindow. Upon doing so, a dialog will appear requesting a caption for the

picture. This dialog also contains a check box marked Link File.

• If checked, only a link to the file will be saved. This option will minimize the file size, but willmean that the photographs will always need to be sent along with result file. (And the two fileswill always need to have the same relative path).

• if not checked, the data from the picture will be embedded into the WavePro result file. This willincrease the size of the file, but will make sure that the picture is always available.

Multiple images can be added to a file. The buttons shown in figure 8.4 allow the images to be manipulatedand the caption to be changed.

• The Scroll Bar chooses which image will be shown at the top left of the display screen (if more thanone image is defined). It has no effect on how the images are printed.

• The ’V and H’ buttons control whether the images are displayed left to right or top to bottom.

• The ’Remove’ button will delete from memory the image that is currently in the upper left cornerof the display.

• The ’Set→’ button changes the caption of the upper left image to the value in the box beside it.

8.4 The summary screen

The ’Summary’ tab is designed to help the operator coordinate a large number of guided wave results andprepare a report from them. Before discussing how the summary screen works, it is helpful to understandthe directory and filename structure that Wavemaker R© WaveProG3

TMuses to organize files.

The Wavemaker R© WaveProG3TM

software uses a variety of subdirectories to store its configuration in-formation and test results. The structure of the directory tree is shown below in figure 8.5. The mostimportant of the subdirectories is the Results subdirectory, which will receive the test results. In orderto keep all of the results well organized, directories will automatically be created for each of the sites atwhich test results were obtained. In addition, a new subdirectory is created for each day of testing. Adate code consisting of the year, month, and day is used for the names of these directories.

Note 1. Depending on the options in the View:Preferences dialog, an additional subdirectory levelof client may be inserted between the main Results subdirectory and the Site subdirectory.

An example of the summary screen can be seen in figure 8.6. At the top there are two pull-down boxes.The first controls how the previous test results will be sorted. It can be either



8.4 The summary screen 89

Caption (Click set to store new value)Click remove to delete the picture from memory

Scro

ll ba

r con

trols

whi

ch p

ictu

re is

act

ive

V an

d H

con

trol t

he o

rient

atio

n of

the

pict

ures

Click and drag jpeg pictures into this window to attach them to a result

Figure 8.4: An example ’Images’ screen.

WavePro1 (contains executable and configuration files) Pipes (contains information about special pipe sizes)

Protocol (contains user defined protocols) [Date of Test 1]

[Date of Test 2]

[Client/Site Name1]

[Date of Test 3]

Base Installation Directory

C:\WaveMkr defaults to:

Results

[Client/Site Name2] [Date of Test 1]

Figure 8.5: Wavemaker R© WaveProG3TM

directory structure.



8.5 Backing up results 90

Figure 8.6: An example ’Summary Screen’.

• By Directory All of the results under a result subdirectory (listed in the second pull-down box)are shown. These results could be from multiple sites depending on the save options or if files havebeen collected together manually.

• By Site Name All of the results with the same site name entered into the ’Site’ box on the’Collect’ tab at the time of collection are shown. The second pull-down box controls what siteshould be shown.

The main portion of the ’Summary’ screen lists details of tests that were performed. Each row representsone test; each column represents a certain type of data. Descriptions of some of the columns is given intable 8.6. Which columns to display (and print) are selected (and reordered) from the self-explanatoryActions:Summary:Choose Summary Columns dialog. The tests can be sorted by a given columnby clicking on the column name. Right click on a row to be presented with a list of actions that can beperformed on that test. The menu option Edit:Find can be used to quickly search the stored tests fora specific string.

8.5 Backing up results

The directory structure described in section 8.4 has been designed to allow results to be easily identifiedand easily copied onto another computer for backup and report generation. Many operators choose tohave one ruggedized computer that is used for the on-site collection and a second computer for the reportgeneration.

The list of which tests exist on a computer is kept separately for each main subdirectory under theResults subdirectory in a file called testlog.iss. If any files are manually inserted (or removed), this filewill become out of date and the summary table that is shown may have incorrect entries. In that case,



8.6 Printing and exporting 91

Table 8.6: Descriptions of the summary information columns.Item DescriptionP Toggles whether a particular test result should be included in the list of test results

to print.ID The is a pseudo-unique ID number that is assigned to each test. It is comprised of

the instrument serial number and a test count.Site, Pipe The site information that was entered when the test was collected.Location This a combination of the Datum and Distance fields.Latitude,Longitude,Altitude,GPSZone

The GPS position that was known at the time of collection. The format of these val-ues can be changed on the View:Preferences dialog. Both ellipsoid and transversemercator projections are supported.

Time The time stamp of when the test was performed. It cannot be changed after thetest has been performed. Therefore, make sure that the computers system time iscorrect.

Features Provides a count of how many features are defined. The small letters provide info-mation about what type of features are defined. A ’c’ or a ’C’ indicates corrosion,’B’ indicates a bend, ’S’ is a support, ’U’ is unknown.

Corrosion Counts the number of corrosion features that have been defined.Page Is the page number that the result was last printed on.

the menu options Actions:Summary:Update Log (current site) should be selected. This will causethe currently active directory to be scanned for files. The entire Results subdirectory tree can be scannedif Actions:Summary:Recreate Log File is selected. This operation can take quite a while if there area lot of files on the computer.

Note 1. If copying files from backup CD to a computer, please ensure that the directories that arecreated are not Read Only. If they are, WavePro will need to recreate the log file each timeit opens, which is very time consuming.

Note 2. When switching from WavePro version 1 to WaveProG3 it is recommended that you performa full log file recreation.

8.6 Printing and exporting

8.6.1 Printing

Most screens can be printed by simply selecting File:Print from the menu.

In order to aid report generation, when the ’Summary’ screen is printed, all of the selected individualtests can also be printed. The File:Print Options dialog controls which of the display screens areprinted. This dialog (see figure 8.2) allows the operator to decide whether to print the summary table(listing a short summary of all of the results), the report pages for each test, the analysis pages for eachtest (with a large copy of the report page), and/or the image page with any attached JPEG images.

8.6.2 Exporting to PDF

The most common export option is File:Export:PDF which creates a PDF file of the currently activescreen (or all printable tests if the summary screen is active). The print options that are active for theformatting or the report are also used for the PDF export.



8.6 Printing and exporting 92

Note 1. The PDF file that is created is not compressed. Opening the file in Adobe AcrobatR©andre-saving the file will significantly reduce its size.

Note 2. The File:Export:PDF-JIS should be used if Japanese letters are used with the reportpages. This adjusts which fonts are embedded into the document and sets the charactermapping to be correct. Similarly, the File:Export:PDF-Chinese options should be usedif the report is written in Chinese. If either of these options are used, the resulting PDF filewill only be compatible with Adobe Acrobat versions 5 and above.

8.6.3 Exporting to Word processors

It is often convenient to incorporate the Wavemaker R© WaveProG3TM

guided wave results into anotherreport document. The Edit:Copy Report menu options are designed to facilitate this operation. Se-lecting Edit:Copy Report copies either the ’Report’, ’Summary’ or ’Images’ screen to the clipboard ina format that is acceptable for pasting into most versions of Microsoft Word R©.

Choosing Edit:Copy from the ’Report’ screen will place all of the summary information on the clipboardin a format that is suitable for pasting int Microsoft Excel R©.



Chapter 9

Maintenance

In order to keep the components of the Wavemaker R©G3 Pipe Screening System functioning well, it isimportant to provide them with routine service and to perform regular maintenance checks. This chapterlists some of the activities that are required. Please refer to section 3.5 for information on checks of theequipment that should be performed before it is used.

9.1 End of day servicing

At the end of each day of testing it is important to identify any faults that may have occurred duringthe day, prepare to store the equipment until the next use and clean the moving the parts so that theywill continue to function freely.

9.1.1 Cables

The cables are one of the most vulnerable components of the system. Therefore, it is important thatthey are checked daily to see if any damage has occurred (for example they were stepped on or cut). It isrecommended that the outside of the cables connecting the electronics to the rings is wiped off with a ragand checked for damage at the same time. The connectors on either end should be carefully examinedfor any foreign items that may have entered them. If soil or sand is trapped in the connectors it shouldbe removed using high pressure air. If pressurised air is not available, the connectors can be cleaned byusing a small brush. However, one must be careful not to bend any of the pins in the Lemo R© connectors.Similarly, the connectors on the USB cable should be checked for dirt that may have collected in them.

9.1.2 Rings

If the transducer rings have been exposed to wet or muddy conditions, they should be wiped off witha dry rag at the end of the day. If the adjustment screws collected debris, they should be cleaned andit should be checked that they move freely. The connection sockets for the cables should be examinedfor dirt and cleaned if required. The inside of the ring should be examined for any missing transducerprobes.



9.2 Monthly maintenance 94

9.1.3 Wavemaker G3 Electronics

The connection sockets on the instrument should be examined for debris that may have collected in themand cleaned if required. If the unit was used in damp or wet conditions during the day, the electronicspackage should be pulled out of its outer box and allowed to dry. The silicone desiccant (if fitted) shouldalso be checked at this point. The internal battery in the instrument should be charged at the end ofeach day of testing (see section 3.6.1). This should be performed indoors.

9.1.4 Wavemaker WaveProG3

At the end of each day, it is recommended that the results collected that day are copied from the harddrive of the computer to another form of storage. This is to ensure that past results will not be lost ifthe computer becomes irreparably damaged. It is possible to find a file on the computer by going to itsentry in the ’Summary’ tab, right clicking on the entry, and selecting Open Folder. This folder canthen be copied to another computer for report writing.

It is also recommended that any notes that have been taken on site, but not already transferred to thereport facilities of the WavePro software, are entered into the software and saved with the test results.With the Wavemaker R©G3 Pipe Screening System, a large number of test results can accumulate quicklyand become confused in an inspector’s memory.

9.1.5 Short Term Storage

When storing the equipment overnight, it should be kept in a dry unsealed environment. If storing theequipment in a packing box, the box lid should be kept open if the instrument has been exposed to waterduring the day or if the batteries are in the process of being charged.

If it is cold or hot outside, the instrument should not be left in a vehicle overnight, but should be broughtindoors.

9.2 Monthly maintenance

After every couple months of use, or when preparing for the start of a new job, the components of theWavemaker R©G3 Pipe Screening System should undergo a more thorough maintenance procedure. All ofthe checks that are listed in sections 3.5, 3.6, 3.7, and 3.8 should be performed.

9.2.1 Cables

The cables should be given a good clean. The connectors should be checked for smooth operation shouldhave any grit blown free with compressed air. Any cuts in the outer coating should be investigated tomake sure they do not damage any of the internal data cables (in which case the cable should be replaced).Any serious cuts in the outer coating of the cables should be patched. Continuity should be checked asdescribed in section 3.7.



9.3 Storage 95

9.2.2 Rings

The rings should be given a though clean to remove and transferred coatings or debris. Then the checksin section 3.8 can be performed.

The overall performance of the ring should be periodically checked by testing a known pipe (that has beenpreviously tested) and comparing the test results. If the inspection job lasts over a month, a locationthat was tested earlier is usually the most practical reference specimen. The results from the two testsshould be nearly identical (except for slight changes in the noise and overall amplitude). If using adedicated test specimen, the ring should be attached one meter from the end of a straight length of newpipe approximately 3 meters long that has nothing welded to it. A test should be performed with thering attached and the results analysed. The reflections from the ends of the pipe should consist almostentirely of symmetric (black) reflections.

A one percent CSC through hole can be added 0.7m from one end as a calibration and comparison target.

9.2.3 Wavemaker G3

The regular Wavemaker R©G3 maintenance consists of

• Checking / replacing the silicone desiccant (if fitted). This procedure is described in section 3.6.7.

• Tightening any mounting screws that may have come loose. The electronic package of the Wavemaker R©G3should be pulled free of its outer box and all of the mounting screws should be checked to makesure that have not vibrated loose in recent journeys. If they have, they should be re-tightened.

• Confirming all self-checks are working. These are described in section 3.6.

9.2.4 Wavemaker WaveProG3

If a software maintenance agreement is in place, regular updates will be placed on the GUL updatewebsite. These updates should be installed on the controlling computers using the procedures as listedon the webpage.

The data should be backed up to a semi-permanent media (such as CD’s) monthly. This data should bestored in a physically separate location from the computer.

9.3 Storage

Before storing the equipment for a prolonged period of time, it is essential that it is allowed to completelydry. This includes internal components in the rings and the instrument that may have been exposed tomoisture. Therefore, it is recommended that the equipment is left unpacked in a dry environment for atleast one day before it is stored in a sealed box. If the inflatable rings are exposed to very wet conditions,it may take them weeks to fully dry.

A log should be kept of any intermittent faults that were experienced with the equipment.

Before storing the Wavemaker R©G3 for a long time (more than 2 weeks), the battery should be fullycharged.



9.4 Shipping 96

9.4 Shipping

The Wavemaker R©G3 instrument should always be well padded and well protected (inside a hard case)when it is being shipped. Many operators choose to hand carry the instrument whenever they fly. If theserial number of the instrument is less than G3-38, then the cover should not be placed on the ’Charge’connection to allow for pressure equalization.

The solid rings should be wrapped in plastic wrap or stuffed with padding in order to avoid having thetransducers fall out (and be lost) when they are being shipped.

The inflatable rings should always have their clamp screws fully tightened down to avoid bending themduring shipping.

Attaching modules to an inflatable ring is usually the most convenient method of shipping them.



Appendix A

Specifications

A.1 General Specification

The following specifications are provided for general information about the Wavemaker R©G3 instrumentand are all subject to change. Please note that the Wavemaker R©G3 Pipe Screening System automaticallycontrols all of the sampling parameters. There is no method for a user to directly control them.

Power Ratings

External power supply voltage to instrument 19 VDC (18-24 VDC) at 100 WattsInternal battery (Li-Ion) capacity 2 off 2200 mAh nominalTypical (new) battery life 50 test sequences (with 10 hours idle time)

Transmitter

Output drive voltage (hardware limited to a 3 msoutput burst every 100 ms)

400 Vpp (140 Vrms) Maximum, 150 Vpp (50 Vrms)Typical

Pulse Shape Arbitrary function generatorMax duty cycle (software limited) 1%

Sampling performance

Sampling frequency 200 kHzConverter resolution 24 bitsMaximum number of averages unlimitedMaximum number of sample points 128000 (Corresponds to test range of 950m)Operating center frequency range 4-75 kHz (15-50 kHz typical)Receiving gain range 10 to 120 dBMaximum number of transducer channels 32Number of independent sampling channels 16Analog high pass filters (switchable) 5,10,20,40 kHz (minimum 4 pole)Analog low pass filters 98 kHz (minimum 8 pole)

A.1 General Specification 98

Physical characteristics

Weight Approx 8 kgDimensions Approx 44x14x40cm

User Interface

Screen 240 by 128 pixel electro-luminescent displayButtons 12 key keypad, iButton

TMreader (Allows data to

be collected without PC attached)

Computer Interface

Communication protocols USB (Appears as a mass storage device)Supported Operating Systems Windows

TM2000,XP

Control Software Supplied Wavemaker R© WaveProG3TM

Other Interfaces

Ring recognition Via integrated IC recording size, geometry, wiringconfiguration, and serial number

Ring capacitance check Can automatically check ring capacitance with 0.1nF precision

GPS Built in non-differential GPS module (typically20m accuracy)

A.2 CE Compliance Notice 99

A.2 CE Compliance Notice

GUL declares that the WavemakerG3 Pipe Screening System conforms to the requirements of the Eu-ropean Council Directive 1999/5/EC, specifically,

• 89/336/EEC (EMC directive with amendments)

• 72/23/EEC (Low voltage directive with amendments)

based upon compliance of the product to the following standards

• Emissions: EN61000-6-4:2001

– EN55011:1998+A1:1999 + A2:2002

– EN61000-3-2:2000

– EN61000-3-3:1995+A1:2001

• Immunity: EN61000-6-2:2001

– EN61000-4-2:1995+A1:1998+A2:2001

– EN61000-4-3:2002+A1:2002

– EN61000-4-4:1995+A1:2001+A2:2002

– EN61000-4-5:1995+A1:2001

– EN61000-4-6:1996+A1:2001

– EN61000-4-11:1994+A1:2001

– EN61000-4-8:1993+A1:2001

Copies of the original Declaration of Compliance can be obtained by e-mailing our support team [email protected]

A.3 FCC and FDA Notices 100

A.3 FCC and FDA Notices

The following information relates to the use of the Wavemaker R©G3 in the United States of America.

A.3.1 Federal Communication Commission

The Wavemaker G3 Pipe Screening System has been test tested for emissions and found to comply withpart 15 of the FCC rules. Operation is subject to the following two conditions:

1. This device may not cause harmful interference

2. This device must accept any interference received, including interference that may cause undesiredoperation.

A.3.2 Food and Drug Administration

Pursuant to section 1002.12 of the regulations for the administration and enforcement of the RadiationControl for Health and Safety Act (Title 21, CFR, Subchapter J) as they pertain to non-medical ultra-sonic equipment, an abbreviated report (initial) has been filed with the FDA and has been assigned theAccession number 0780463.

Appendix B

Safety Summary

Various safety issues are mentioned in this document at the appropriate places for their application. ThisAppendix repeats the issues that have been raised, collecting them together in one place.

B.1 Plant issues

Many of the safety issues that are raised by using the Wavemaker R©G3 Pipe Screening System are verysimilar to those that are raised by the use of conventional manual ultrasonics sets.

All of the components of the Wavemaker R©G3 Pipe Screening System are battery operated. However,they are not intrinsically safe and will therefore require a hot work permit at most locations. Most siteswill require readings of the level of explosive gases before the equipment is turned on at each test location.If required, this should be made part of the work permit. Please note that maximum battery voltage is16.8 volts (when fully charged). The maximum voltage seen at the piezo-electric ultrasonic transducersis 400 Vpp (150 Vrms). However, in normal operation, the Wavemaker R©G3 runs with a peak output of150 Vpp (50 Vrms).

The system is electrically isolated from the pipe under test and there are no couplants used, so no residuewill be left on the pipe.

A small amount of the paint on the pipe may be scraped off during the test. This usually occurswhen loose, flaking, material is removed to get good contact with the pipe wall. It may also occur atsmall locations directly beneath each transducer. If the paint is a very important part of the corrosionprotection, the paint surface may need to be touched up after the test.

If the pipe is very heavily corroded, extra care must be taken when applying the transducer rings. Eachtransducer applies the equivalent of 20 kilos of force to the pipe. Therefore, if the pipe wall has beengreatly reduced by corrosion (for example to less than 0.5 mm remaining wall), applying the transducerscould damage the pipe. If there is very heavy corrosion at the test location, it is recommended thatthis technique is not used, since in addition to the risk that the pipe may be damaged, the range willbe greatly reduced by the heavy attenuation caused by severe corrosion. In this case, complementarytechniques such as manual ultrasonics or radiography may be more effective.

B.2 Personnel 102

B.2 Personnel

In addition to the standard personal protective equipment (PPE) that will be required for the site, glovesshould always be worn when applying and removing the rings and when connecting the cables to therings.

When working on pipes at elevated temperatures, gloves are imperative. In addition, heat tracing shouldbe turned off whenever feasible.

When using an inflatable ring it is especially important that the thumbs screws on the clamp fit into thedimples on the other half of the clamp. If the screws are not inserted into the proper holes, the ring maycome off when it is inflated, which could harm the operator. In addition to ensuring that the clamp iswell seated, it is recommended that the operator stands to the side of the inflatable ring when inflatingit.

The inflatable rings should never be inflated above 35 psi (2.5 bar). The pump that is used must alwayshave a pressure gauge.

In most cases, the most risky portion of performing the test will be accessing the test point, which ofteninvolves climbing over pipes or up scaffolding. Some of the rings weigh over 10 kilos and could causesignificant harm if they were to hit someone after being dropped from a high location. Therefore, therings should be raised to and lowered from scaffolding using ropes. The equipment should be arrangedto minimise trip hazards. The site should always be kept tidy.

The Wavemaker R©G3 instrument should always be charged indoors. The batteries must remain dry, notbe short-circuited, and never be burnt.

Appendix C

Glossary

The following list summarizes some abbreviations and terms that will be used in this document.

Axial Direction - The direction along the axis of the pipe (see figure C.1)

Axial Length - The length of a pipe feature in the axial direction.

Circumferential - The direction along the around the axis of the pipe (see figure C.1)

Cross Section - Imagine the pipe cut open in a plane perpendicular (= at a right angle) to the mainaxis. The cross-section is the entire area between the inner and the outer radius of the pipe. It isthe gray area in figure C.1. In a simple pipe without features the cross-section is constant alongthe main axis.

CSC - Cross-Sectional area Change. A change in cross-section is either a decrease (removal of wallmaterial) or an increase (addition of material) in cross-section area. A decrease in cross-section canbe caused, for example, by material loss due to corrosion. A weld, for example, increases the cross-section. The change in cross-section is commonly given as a percentage of the normal cross-section.The WPSS measures changes in cross-section.

Circumferential Extent - refers to how the change in cross section in distributed around the pipe’scircumference. Is it evenly distributed or clumped together? This is normally expressed as apercentage of the total circumference. A weld has a circumferential extent of 100%. Figure C.2demonstrates this concept.

ECL - Estimated Cross sectional Loss. An estimate of what percentage of the cross section has beenlost. (Frequently used inter-changeably with CSC.

Feature A pipe feature defined as any prominent part of installed pipe-work apart from the pipe itself.

GUL - Guided Ultrasonics Limited.

GW - guided waves. Waves that are constrained by the boundaries of the system in which they arepropagating are said to be ’guided’.

GWUT - guided wave ultrasonics. A term that GUL usually uses to refer to screening pipes withguided waves (such as those performed by the Wavemaker R©G3.)

LRUT - long range ultrasonics. A term that some competitors prefer to use instead of GWUT for thesame type of inspection.

Mode - in guided wave testing, the boundaries of the system (the pipe) limit what speeds at whichwaves can travel. Each type (and speed) of wave that can exist is called a mode.

Orientation - At what circumferential orientation is the center of average cross sectional change.

104

pipe axis pipe axis

Axial direction Circumferential Direction

Figure C.1: Naming convention for the axial and circumferential directions.

25% 100%75%50%

Figure C.2: Definition of circumferential extent.

Symmetry - A pipe itself is axisymmetric (or axially symmetric, symmetric about the axis). Thatmeans that every point on a circle around the pipe axis as the centre looks the same. Similarly, apipe feature is axisymmetric if it looks the same all around the pipe. For example, a good weld islargely, apart from small variations, axisymmetric.

Non-axisymmetric means that the axisymmetry is broken. For example if there is a hole in thepipe, the pipe does not look the same all around the circumference. Even if there is the same holeon exactly the opposite side, the pipe is not axisymmetric because it must look the same at everypoint.

When this document discusses about symmetry, it is always referring to axisymmetry; there is noimplication about the shape along the axis of the pipe.

Wall Loss Unlike cross-section change, which is a change in total pipe wall area, wall loss is simply achange in the pipe wall thickness. The WPSS does not measure absolute wall loss. See figure C.3for an illustration.

WPSS - Wavemaker Pipe Screening System

Echoes - Used interchangeably with reflections to indicate the processed wave that has been reflectedfrom a feature.

105

Definition of cross-section; 0%change

Approximately 15% change incross section

An exact 25% change in crosssection

0% wall loss. Approximately 90% maximumwall loss and 60% average wall

loss

100% wall loss

Figure C.3: Examples of cross section loss versus wall loss.

Appendix D

Training Scheme

The following information is an overview of the Guided Ultrasonics Ltd. (GUL) operator training schemeas it was defined at the time that this manual was written. It is included in this manual because operatortraining and qualification are considered to be a integral part of the operation of the Wavemaker R©G3Pipe Screening System.

The newest full version of the training scheme can be found on the GUL web site, www.guided-ultrasonics.com.

D.1 Introduction

The GUL WPSS uses guided wave technology as a screening technique for pipes. Respected peoplewithin the NDT industry have described this technique one of the few genuinely new techniques to beintroduced in the last 20 years. This in itself presents a whole new set of challenges to ensure that alloperators are trained and competent to use the equipment, to gather data and interpret the results.

The introduction of any new technology is never easy and is very dependent on the reputation it gainson every job undertaken using it. This technique like most other NDT techniques is highly dependent onthe quality of the operators that use it.

GUL has designed the WPSS equipment such that the data collection under default parameters is fullyautomated allowing the operators to concentrate on interpretation. The ability of the operators is crucialto the successful implementation of this technique.

With this in mind GUL has adopted the policy that the first equipment purchase by any user organisationmust always include a training and support package. This package consists of both classroom trainingand field support for the newly trained operators. Purchasers have also entered into an agreement at thetime of purchase only to use qualified technicians as the lead inspector in any screening team. Evidenceof continual use of the equipment is required for revalidation of an operator’s qualification.

GUL is conscious that:

1. The reputation of the technique is inextricably linked to the ability of the operators.

2. At present no other organisation is sufficiently experienced in this technology to undertake eitherthe training or develop training courses. As the technique becomes more widely available however,it is anticipated that a Training Scheme may be accredited and carried by one or more of therecognised independent training/qualification bodies.



D.2 GUL qualification levels 107

3. In compiling this training scheme, similarities to ASNT and PCN training schemes have beenadopted as they are recognised industry standards. The primary difference is that GUL level 1 isgenerally higher than the equivalent ASNT or PCN when it comes to recommended applicationsthat can performed. General similarities can be drawn as to how it is used and maintained as anoverall scheme.

4. There are other types of guided wave equipment on the market so GUL recognises that althoughthe physics governing the operation of all the systems is very similar, the method of application isvery different and that GUL training refers only to competence in operating the WPSS.

5. All training qualifications are authorised by the GUL Chairman in order to ensure compliance withthis scheme.

D.2 GUL qualification levels

The GUL training scheme defines 3 levels of qualifications.

Level 1 The primary practitioner level. Is trained to perform data collection and analysis of simpleinspection situations.

Level 2 Advanced practitioner level. Has extensive site experience and is trained to collect and analyzedata for a wide variety of challenging application areas. Has a basis practicaly knowledge of thetheory behind the inspection.

Level 3 Theoretical understanding. Has been heavily trained on the theory behind the inspection tech-nique and how to extend application areas. However, does not necessarily have much site experience.

GUL recommends that certain inspection situations are only performed by a Level 2 operator or a Level1 operator who has had supplemental training the specialist area. A list of these areas can be found inthe next appendix..

D.3 Viewing an operator’s qualification level

There are several ways to determine an operator’s qualification level:

G3 Instrument Information about the operator such as their qualification levels, supplementary courses,and test number log can be obtained, by going to the ’ID!Operator’ screen on the G3 instrument,pressing the ”Logon” button, and holding the operator ID key to ID reader.

Operator certificate and cards All GUL operators should be issued with a paper certificate and acredit card sized qualification card after they have successfully completed a qualification level.

Contact GUL GUL keeps a record of all qualifications that have been issued. Contact [email protected], to validate any operator’s qualification level. Please quote the operators nameand employer.

GUL qualifications are only given for a limited period of time. In order to renew the qualification,evidence of having been using the equipment in a frequent and correct way must be presented to GUL.Alternatively, a refresher training course will be required.

Appendix E

Application Levels

The following tables list the application levels that are appropriate for various types of inspection appli-cations.

For training applications, the qualification levels are mandatory; for all other applications, they arerecommended. Certain qualification levels may be required by the end-client for particular inspectionjobs.

The code Level 2 (1S)should be read as ”Level 2 or a Level 1 who has attended the appropriate sup-plementary course or who is working under direct Level 2 supervision”. Certain application areas arecovered by specific supplementary courses that instruct Level 1 operators in the interpretation of a tar-geted advanced inspection area. In some of the other cases, the work can be started by a Level 1 operatorin consultation with a Level 2 operator. Ideally, a Level 2 operator should also review a large proportionof the result (certainly the first few).

Application description Type Qualification Level

TrainingLevel 1 training course (lead trainer) Advanced Level 3Level 1 training course (second trainer) Advanced Level 2Level 1 Examination and issue of qualification Advanced GUL onlyLevel 2 training Advanced D. Alleyne or B

Pavlakovic onlyLevel 3 training Advanced GUL OnlyProcedure development Advanced Level 2/3Written practice for applications Advanced Level 2/3Auditing reports Advanced Level 2/3Auditing field activities Basix Any attendee of GUL

appreciation or train-ing course

Auditing of results/findings Intermediate Level 2/3

Straight above ground runsLong lengths of simply supported pipe in pipe rack Basic Level 1

MonitoringSimple sample monitoring (in place of random thicknesschecks)

Basic Level 1

Monitoring after period using ”repeat shot” and ”overlay”features

Intermediate Level 2 (1S)

109

Buried pipe applicationsRoad crossings in sleeves painted (no special coatings norwelded supports)

Basic Level 1

Road crossings in sleeves painted (no special coatings) withcentering lugs


Buried pipe in sand/earth painted (no special coatings) Advanced Level 2 (1S)Buried pipe with attenuative coatings Intermediate Level 2 (1S)Short transitions through bund walls etc Intermediate Level 2 (1S)

Different materialsStainless steel Basic Level 1Plastic to check welds Advanced (GUL only) Level 3

Testing pipes with different contentsGas-low velocity Basic Level 1Gas-high velocity Basic Level 1Low viscosity (thin) liquids Basic Level 1High viscosity (thick) liquids Basic Level 1Very high viscosity liquids Intermediate Level 2 (1S)Liquids that leave attenuating internal deposits Intermediate Level 2 (1S)Minor internal scale up to 2mm thick Basic Level 1Internal Scale over 2mm thick Intermediate Level 2 (1S)

Identification of specific defectsErosion Advanced Level 2Defects in bends Advanced Level 2Defect in weld Advanced Level 2Identifying corrosion under simple supports Basic Level 1Identifying corrosion under welded/clamp supports Advanced Level 2

Testing pipes with coatingsPaint Basic Level 1Mineral wool insulation Basic Level 1Polyeurathane foam Basic Level 1Polyethylene coating Basic Level 1Spun epoxy coating Basic Level 1Epoxy hand applied Splash zone coating Advanced Level 2 (1S)Bitumen wrapped pipe (in interface zone (< 2m)) Advanced Level 2Bitumen wrapped pipe (maximum range) Advanced Level 2Concrete lined Advanced Level 2 (1S)Denso wrapped Advanced Level 2 (1S)Corrosion scale removalable by wire brush Basic Level 1Severe corrosion with layers of scale that have to be removedby chipping off


Specific applicationsTesting of sphere legs under concrete fireproofing Advanced Level 2Risers Advanced Level 2Very noisy environments Advanced Level 2Tubular lamp posts Intermediate Level 2 (1S)

Sub-seaAll sub-sea activities are considered advanced Advanced Level 2

110

The following example can help illustrate how the table above is to be used.

Where a pipe requires testing appears in good condition and is supported it would, according to theabove list be a basic application carried out by a level 1 inspector. If this same pipe is wrapped in densotape then the application becomes Level 2 (1S), requiring a more experienced level 2 inspector or a level1 inspector with specialist training.

Generally several parameters apply to any pipe so the most severe operator requirement is the one thatgoverns the recommended qualification level.

Appendix F

Index

’Unrolled Pipe Display’, 61

Accession Number, 100Actions, 5, 68

Calibrate Distance, 83Reanalyze, 49Special:Truncate Data, 84Summary:Choose Report Columns, 82Summary:Choose Summary Columns, 90Summary:Recreate Log File, 91Summary:Update Log (current site), 91Upload from G3, 49

Actions:Enter G3 Licence Key, 10Actions:Redetect Ring, 44Actions:Special:Adjust Contour Options, 62Administrator, 8Analysis, 62, 66Analyze, 51, 56, 66, 82analyze, 57Animate, 62Appliance

class, 22Applications

Frequency choice, 16Assessing job, 11Attachments, 88Attenuation, 55Autoscale, 68Axial

direction, 103length, 103

BandwidthFrequency, 63

Batteries, 20By Directory, 90By Site Name, 90

C-Scan, 16, 61Cables

Checks, 27Removal, 27USB, 26

Call DAC, 55Capacitance

Check, 32Card Check, 24CE, 99Change Saved Site, 82Charge, 20Charging

G3 batteries, 20Check, 28Check Z, 32Check:Cables, 28Check:Cards, 24, 25Checks

G3, 20Inflatable, 30Rings, 29Solid, 29

Circumferentialdirection, 103

Circumferential extent, 58Clamping

Solid rings, 39Class, 83Class I, 22Classification, 78coating, 45Coatings

Removal, 37Cold, 38Collect, 45, 46, 82, 86, 87, 90

G3, 47PC, 46

Configure:Auto-Fit DAC:From Calibration, 69Configure:Auto-Fit DAC:To Features, 69Configure:Auto-Fit DAC:To Welds, 69Configure:DAC Level, 56Configure:DAC Levels, 55, 56, 70Configure:Operator, 87Cross section, 103CSC, 57, 60, 78, 103

DAC, 53, 69Autofit, 69Dialog, 56Levels, 55Surface, 55

Wavemaker G3 User Manual Index

DAC surface, 55Datum, 46Dead zone, 66Device:Files, 49Directories, 88Distance, 47

Echoes, 104ECL, 57, 78, 83, 103Edit:Copy, 92Edit:Copy Report, 92Edit:Find, 90Edit:Stretch DACs, 70EFC, 16, 18, 62End of Test, 19End of test, 71Esc, 47Extending

USB Cable, 26Extent, 58, 83Extra Info, 47

F11, 67F2, 67F4, 68F5, 5, 67F7, 47False echoes, 73FCC, 100FDA, 100Feature, 83, 103Feature Columns, 83Feature Detail, 56, 70, 82, 83, 86Feature List, 82Feature Properties, 70File:Export:PDF, 91File:Export:PDF-Chinese, 92File:Export:PDF-JIS, 92File:Open, 49File:Print, 91File:Print Options, 73, 82, 84, 91File:Print Setup, 86Filename

format, 47Flange DAC, 55Focussing, 61, 62Force Redetect, 32Freezing, 38Frequency

Bandwidth, 63behaviour, 62

Frequency regime, 11Full Check, 24

General Information, 82Go, 5, 47, 48GPS, 87GW, 103

GWUT, 103

Header/Footers, 84Help:About, 10High Ambient Noise, 46High Noise Filter, 46Hot, 37

ID, 23Operator, 107

ID:Licence, 10ID:Logon, 23ID:Operator, 23Images, 81, 89, 92Impedance

Check, 32Inflatable Rings, 16Info, 20, 24Info:Main, 44Info:Stats, 5, 20, 24Info:Versions, 24Install

Software, 7Interpretation, 54

Welds, 68

JPEG, 85, 88

Latitude, 83leakage, 55Length, 83Licence, 9Link File, 88Location, 83Logo, 82

Options, 85Logoff, 23Logon, 5, 6, 23, 107Longitude, 83LRUT, 103

M, 83, 86Maintenance, 94Measure, 67Measure Pipe Wall, 47Mirroring, 73Modal noise, 76mode, 103Modules, 16

Frequency regime, 18Types, 17

Near field, 66Noise DAC, 55Notes, 83

Open Folder, 94Operator Notes, 47Operator Verified, 81

Wavemaker G3 User Manual Index

Orientation, 78, 103

P, 83Packing List, 21Packing list, 19Phase, 54, 63, 83Photos, 88Pipe, 46Pipe schedules, 16Pointer, 67Power, 6power, 23Properties, 69, 70Protocols, 45

Questions, 12

Radial loss, 61Rain, 41Range, 13, 18, 19, 47, 71Range Down, 47Range Up, 47Read Rings, 32Regime, frequency, 11Remove, 88Report, 58, 70, 79, 81–83, 87, 92

Formatting, 85Graph formats, 86Options, 86

Report Notes, 47, 82Reports, 84Result graph, 82Reverberations, 74Ring, 6Ring:Coupling, 34, 43, 45Ring:Impedance, 32, 45Ring:Info, 44Ring:Ring ID, 32Rings

Checks, 29Inflatable, 16Selecting, 13Solid, 13

Safety issues, 101Save to Flash, 47Save to USB, 47Schedules, 13, 16Sensitivity, 13Sequence complete, 48Servicing, 93Set→, 88Shape, 60, 79Shift-F4, 68Short Range Screening, 46Site, 46, 90Size, 83Solid rings

Frequency regime, 16Special, 5Specifications, 97Start, 47Status, 49Storage, 94, 95Summary, 81, 82, 88, 90–92, 94

Columns, 91Summary Information, 81Summary Screen, 90Support

frequency, 62Surface

DAC, 55Survey, 12Symmetry, 59, 78, 104

Temperature, 37Case, 44Charging, 20Limits, 37Low, 38

Test range, 18Thick pipes, 13, 76Thin pipes, 13, 76Tools

Interpretation, 54

Unrolled, 16pipe, 61

Upgrades, 10USB, 26UTM, 87

V and H, 88View : DAC Curves, 55View : Preferences, 57View:Custom Zoom, 68View:Preferences, 47, 83, 84, 87, 88, 91View:Processed Data:Extend Frequency Range, 46View:Processed Data:Feature ECL, 58View:Processed Data:Stacked, 73View:Raw Data:Frequency:Calibration Data, 51View:Raw Data:Frequency:Single Unfiltered, 51View:Raw Data:Time:Calibration Data, 51Visco-elastic, 55

Wall, 83, 86Wall Loss, 104WavePro

Directories, 88Weld DAC, 55WGS84, 87WPSS, 104

Zoom, 67

Wavemaker G3 User Manual Notes

gul wavemaker g3, procedure based training manual

Documents

test location

test result

test ranges

end of test

basic checks

wavemaker g3 instrument

ring cable checks

writing fromguided ultrasonics