AUT General _ UT-06566_Rev.E

Number : UT-06566 GENERAL Revision : E AUTOMATED ULTRASONIC TESTING Date : 14.03.2007 (AUT) PROCEDURE Page : 1 of 27

Röntgen Technische Dienst bv

Copyright RTD Delftweg 144, 3046 NC ROTTERDAM, NL

Project : KGSSP project (QSTP to Khurais Seawater Supply

Pipelines and Ghawar Seawater Supply Pipelines Expansion.

Contractor : Saudi Arabian Saipem Ltd. Owner : Saudi Aramco AUT Contractor : Röntgen Technische Dienst b.v. Scope : General Automated Ultrasonic Testing (AUT)

Procedure of GMAW Pipeline Girth Welds including Repair welds.

Diameters : 42; 56 & 60 inch. Wall Thickness : 42 inch; 11,1 & 13,3mm Material X65 56 inch; 11,9 & 13,1mm Material X65 60 inch; 14,1 & 12,7mm Material X65 60 Inch; 14,0; 16,8; 17,2 & 20,7mm Material X70 Based on : API 1104 20th Edition, November 2005 Validity : This procedure is valid only for UT-examination of welds with a surface temperature up to 90°C.

UT-06-566-spec reference the Specific AUT set up configuration for each pipe size, wall thickness and weld configuration.

E

14.03.2007

D C

13.03.2007 07.03.2007

Rev.No. Date Approval Level III RTD

Approval Client

Approval Third Party




© 2006 Röntgen Technische Dienst b.v.

This document has been produced by Röntgen Technische Dienst b.v. (RTD)

With the exception of the use within the organizations of Contractor and Owner, but on this particular project only, no part of this publication may be reproduced, stored in a

retrieval system, or transmitted in any form or by any means without the prior permission of:

Röntgen Technische Dienst b.v.

Inquiries in The Netherlands can be directed to ; Company RTD Project Services Address Delftweg 144, 3046 NC Rotterdam Place P.O Box 10065, 3004 AB Rotterdam Country The Netherlands Phone +31(0)102088212 Fax +31(0)104158943 Internet www.rtd-group.com

Inquiries in the USA can be directed to ; Company RTD USA Address Suite 300,10540 Rockley Road Place Houston, TX 77099 Country United States of America Phone +1 8322955000 Fax +1 8322955001 Internet www.rtdquality.com

Inquiries in Australia can be directed to ; Company RTD Steeltest Address 2 Thorpe Way Kwinana Beach Place Perth, WA 6167 Country Australia Phone +61(0)894395656 Internet www.rtdsteeltest.com.au




CONTENT 1 PURPOSE.........................................................................................................................................5

2 SCOPE ..............................................................................................................................................5

3 REFERENCED DOCUMENTS ......................................................................................................6 3.1 RTD IN-HOUSE DOCUMENTS (AVAILABLE FOR REVIEW) ..........................................................6 3.2 NATIONAL CODES AND STANDARDS .........................................................................................6

4 DEFINITIONS ...................................................................................................................................6

5 PERSONNEL QUALIFICATIONS.................................................................................................7 5.1 AUT ROTOSCAN OPERATOR ....................................................................................................7 5.2 THE SCANNER TECHNICIANS ....................................................................................................7

6 MECHANIZED ROTOSCAN EQUIPMENT DESCRIPTION ( CONVENTIONAL ) ...............7 6.1 MULTI-CHANNEL ULTRASONIC EQUIPMENT .............................................................................7 6.2 RECORDING...............................................................................................................................8 6.3 SCANNER AND UMBILICAL .........................................................................................................8 6.4 CALIBRATION SET-UP................................................................................................................9

7 MECHANIZED ROTOSCAN EQUIPMENT SET-UP ( CONVENTIONAL ) ............................9 7.1 INSPECTION SET-UP CONFIGURATION......................................................................................9 7.2 PROBE CONFIGURATION ...........................................................................................................9 7.3 PROBE FRAME LAYOUTS ..........................................................................................................9 7.4 PARAMETERS OF ROTOSCAN INSPECTION PROGRAM .............................................................9 7.5 REFERENCE STANDARD..........................................................................................................10 7.6 ESSENTIAL VARIABLES............................................................................................................10

8 EQUIPMENT SET UP ...................................................................................................................11 8.1 GENERAL .................................................................................................................................11 8.2 SETTING OF INSPECTION GATES ............................................................................................11 8.3 SENSITIVITY SETTINGS ...........................................................................................................11 8.4 REFERENCE LEVEL .................................................................................................................12 8.5 SCANNING LEVEL ....................................................................................................................12 8.6 EVALUATION LEVEL (GO-NOGO LEVEL) .................................................................................12 8.7 PROBE SELECTION..................................................................................................................12 8.8 SIGNAL TO NOISE VALUES IN THE GATED AREA......................................................................12

9 SCANNING PREPARATION & SURFACE CONDITION .......................................................12

10 REFERENCE LINE........................................................................................................................13

11 ACOUSTIC COUPLING FLUID...................................................................................................13 11.1 COUPLING SET-UP ..................................................................................................................13

12 EXAMINATION ..............................................................................................................................13 12.1 DYNAMIC CALIBRATION CHECK ..............................................................................................13 12.2 CALIBRATION FREQUENCY......................................................................................................14 12.3 CIRCUMFERENTIAL SCANNING DIRECTION .............................................................................14




12.4 DATUM POINT..........................................................................................................................14 12.5 STEP BY STEP DESCRIPTION OF A ROTOSCAN EXAMINATION ...............................................15

13 INTERPRETATION OF RESULTS .............................................................................................15 13.1 GENERAL .................................................................................................................................15 13.2 IMPERFECTION LENGTH ..........................................................................................................16 13.3 IMPERFECTION HEIGHT ...........................................................................................................16 13.4 IMPERFECTION DEPTH ............................................................................................................16

14 DETERMINATION OF WELD ACCEPTABILITY .....................................................................16 14.1 DETERMINE WHETHER SECTION 9 OR APPENDIX A OF API 1104 IS APPLICABLE .................16 14.2 INDICATIONS (GENERAL).........................................................................................................17 14.3 IF IMPERFECTIONS EXIST DETERMINE HEIGHT, LENGTH, AND DEPTH ..................................17

15 ACCEPTANCE/REJECTION CRITERIA ...................................................................................20 15.1 API 1104 SECTION 9 CRITERIA..............................................................................................20

16 RULES FOR GMAW REPAIR (S)...............................................................................................21

17 REPORTING...................................................................................................................................21

18 STORAGE OF DATA ....................................................................................................................22 Attachment 1: Example of Probe Frame Configuration Attachment 2: Example Rotoscan Site-Report Attachment 3 Example Rotoscan Defect info print-out Attachment 4: Decision Flow Chart




1 Purpose The purpose of this procedure is to detail the methodology used for the Automatic Ultrasonic Testing (AUT) of circumferential GMAW Pipeline Girth Welds including Repair Welds during the KGSSP Project, following the requirements of API 1104 20th

Edition, November 2005. The Project ‘Specific AUT procedure UT-06566-Spec…. (relevant WPS no)’ is to complement this General AUT Procedure for the KGSSP Project. Each ‘Specific AUT Procedure’ addresses the actual system configuration, set-up parameters and (if applicable) additional acceptance criteria for each pipe size, wall thickness and weld configuration. 2 Scope This procedure details the process to be followed for AUT (via the RTD Rotoscan system) of the following diameter pipes and nominal wall thicknesses.

QSTP to Khurais Seawater Supply Pipelines

Ghawar Seawater Pipelines Capacity Increase

Girth Butt Weld Examination Details

Diameter Nominal Thickness Material Welding process

56 inch 11,9 mm API 5L GR X65 GMAW






Girth Butt Weld Examination Details

Diameter Nominal Thickness Material Welding process








3 Referenced Documents

3.1 RTD In-house Documents (available for review) • CP-31105 Calibration Check Procedure for Ultrasonic Multi Channel

Equipment. • CP-31108 Control Procedure of Calibration Blocks for the Rotoscan System. • A-512 “Written Practice” for the Training, Qualification, Certification and Authorisation of NDT Personnel. • UT-06-549-spec “Specific Automated Ultrasonic Testing Procedure for

the EWPL Project”

3.2 National Codes and Standards • API 1104 20th Edition, November 2005 • ASTM E 1961“Standard Practice for Mechanized Ultrasonic Examination of Girth Welds Using Zonal Discrimination and Focused Search Units”

4 Definitions

• “Scanner Technician” refers to the person responsible for maintaining and operating the AUT scanner. • “AUT Operator” refers to the person responsible for all ultrasonic

aspects of the inspection, recording and interpretation of results. • “Band Setter Technician” refers to the person responsible for adjusting the band to meet the scribe line or weld centre. • “Scribe Technician” refers to the person responsible for scribing the reference line on the pipe after the weld bevel has been machined. • “Length” of an indication will be defined if it has at least one amplitude value equal to or greater than the threshold amplitude. • “Through Wall Height” dimensions of the indication will be called the “Vertical Height” of the defect. • “Depth” of the indication is the through-wall distance to the bottom of the defect as measured from the outside diameter of the pipe • “Interzonal Imperfection” is one that occurs at the overlap of two adjacent ultrasonic zones. • “Stacked Imperfection” consists of multiple discrete imperfections in different weld passes occurring at the same circumferential location. • “Procedure” is a step-by-step description of the application of an NDT method. • “Instruction” is a description of the steps to be followed when performing an NDT procedure. • “UT Channel Convention” is the way UT channels are called from the inside out, i.e. From centre screen and are called Root, Hot Pass, Fill- channels, and Cap. • “AUT” is Automatic Ultrasonic Testing • “Rotoscan” RTD Brand name for our AUT System • “P.R.F” is Pulse Repetition Frequency • “MUT” is Manual Ultrasonic Testing • “Shall” is a mandatory term




• “FBH” is Flat Bottom Hole • “Should” is a recommended practice or action. • “Defect” is an imperfection of sufficient magnitude to warrant rejection based on the criteria referenced by this procedure. • “Imperfection” is a discontinuity or irregularity that is caused by the welding process and is not related to geometry indications. • “Indication” is evidence obtained by non-destructive testing. • “ECA” is an Engineering Critical Assessment.

5 Personnel Qualifications

5.1 AUT Rotoscan Operator Performs the interpretation and reporting of the Rotoscan DATA files. Be qualified in accordance with the requirements of ASNT CP-189. Only personnel qualified to Level II or Level III shall interpret the test

results. Has documented experience with multi-channel UT-equipment; Be trained and passed the RTD in-house testing for Automated Ultrasonic Inspection Shall attend a practical Manual UT examination by Saudi Aramco for

approval.

5.2 The Scanner Technicians • Performs the guiding band setting and attaches the scanner to the band • Be trained in using an AUT-scanner to the satisfaction of AUT Rotoscan Operator

6 Mechanized Rotoscan Equipment Description ( Conventional ) The Mechanized Rotoscan system is an automated ultrasonic inspection system for pipeline girth welds, based upon the ‘Pulse Echo Method’, enhanced with mapping images and ‘Time of Flight Diffraction’ (TOFD). The weld is divided into a number of depth zones, which are inspected by a set of probes. These probes are arranged such that the entire weld is examined from both sides in one single circumferential scan. The ultrasonic information is transferred to a computer for data presentation and analysis.

6.1 Multi-Channel Ultrasonic Equipment The multi-channel ultrasonic equipment used shall provide an adequate number of inspection channels (referred to as sequences) to ensure a complete volumetric examination of the weld through thickness in one circumferential scan. Each inspection channel will provide a linear “A” scan presentation, which can be individually selected.




The systems provide the following:

6.1.1 Gate Parameters In each sequence, the following parameters are selectable:

Transmitter and Receiver channel 1- 32 Gain 0 - 40 dB (1dB increments) Gate start and length. (minimum increment 0.1mm ) Delay (mm) Threshold level 5% - 100% Full Screen Height (FSH) Recordable output selection between; Amplitude and/or Transit Distance,

Mapping, TOFD and Coupling. Selection between First / Highest Amplitude detection within the gated

section

6.1.2 General The signal to noise ratio of each sequence during examination shall be at least ≥ 20dB for shear wave’s probes. Refer to chapter 8.8.

6.2 Recording Inspection results are presented on-line typically with a colour monitor. The screen layout and number of used sequences are configured to present the thickness of the weld to be examined. Distance delays are applied to the output channels to compensate for variable probe circumferential positioning. The presentation shows the following information;

• Amplitude and relevant transit distance (superimposed) • Mapping image sections • Go-Nogo image section • Coupling check section • ToFD image section • Circumferential position information • Header section to present job specific information • Time and Date of inspection • Indication mark up • Geometry mark up

6.3 Scanner and Umbilical The scanner /umbilical to be used provide the following:

Automated operation during examination, Easy and quick mounting to the guide band. Capable of taking a minimum of 12 individually spring loaded ultrasonic

probes for the Conventional, of which the distances to the weld centreline can individually be set. Coupling - controllable per probe, or per set. 15-45 meters of cable length.




The scanner is equipped with an encoder for accurate measurement of the scanner position within the pipeline circumference. The encoder

accuracy shall be +/- 10mm Minimum speed of 40 mm/sec Maximum speed of 80 mm/sec

6.4 Calibration Set-up The calibration set-up consists of a support of the same diameter as the project pipe. Within the support, there is a cut-out area, which is where the Reference Standard is mounted. The Reference Standard(s) to be used are made from uncoated project pipe. On the support, a guide band is mounted at the same distance from the Reference Standard centreline as the guide band on the weld to be tested. 7 Mechanized Rotoscan Equipment Set-up ( Conventional )

7.1 Inspection Set-up Configuration The Specific inspection set-up for each diameter and wall thickness are shown in UT-06566-spec. These include the probe angle(s) for the selected Pulse-Echo, Mapping & TOFD techniques within the zones to be examined and within the given weld bevel configuration.

7.2 Probe Configuration Specific AUT Procedures UT-06566-spec illustrates the selected probe configuration for each specific inspection set-up. All probes have a unique number for QA/QC purposes, which relate to the manufacturing process and tests conducted within the RTD probe-manufacturing department. These probe numbers are entered into the inspection parameter file held within the Rotoscan inspection program.

7.3 Probe Frame Layouts The probes used for inspection are positioned within a probe frame. The position of each probe in circumferential direction and its inspection function are illustrated in Attachment 1 (example).

7.4 Parameters of Rotoscan Inspection Program During inspection the parameter settings of the Rotoscan program are stored on the computer hard drives together with all inspection data. The settings for each inspection sequence are subject to adjustment within the defined essential variables. Refer to Section 7.6.




7.5 Reference Standard Reference standards shall be used to qualify the system for field inspection and to monitor ongoing system performance. Reference standards shall be manufactured from a section of project specific line-pipe of matching wall thickness supplied by the Company. Standards shall be designed such that the target reflectors simulate the bevel geometry to be inspected. The block shall be designed with sufficient surface area to enable the probe array to scan the target areas in one single pass. The principal calibration reflectors for fusion defects shall be 3 mm diameter flat bottom holes (FBH) and surface notches with a depth of 10% from the wall thickness. The principal reflectors for porosity detection shall be 1,5mm FBH's. The central axis of each FBH calibration reflector shall coincide with the central axis of the sound-beam interrogating it. The lateral position of each calibration reflector shall be such that there will be no interference from adjacent reflectors, or from the edges of the standard. The Reference Standard shall be manufactured and tested according to the applicable RTD in-house Control Procedure. The Reference Standard shall be identified with a hard stamped unique serial number. Specific AUT Procedure UT-06566-Spec refers to the Reference Standard(s) manufacturing drawings of each respective welding process, diameter and wall thickness. Note:

2mm φ through-holes at both ends of the Reference Standard at centreline are to locate the weld centre position only.

Cap/Root notches are to indicate the weld bevel position. TOFD notches are used to identify surface breaking indications.

7.6 Essential Variables A. Set-up Change resulting in beam angle of +/- 2° in steel. B. Conventional Probe Parameters Change in Frequency and Crystal size C. Software Version A change of software version (unless written permission is provided by the Company) D. Material (steel all grades) Change in nominal wall thickness; change in nominal pipe diameter. E. Gates Change in gate transit distance of >1.5 mm or raising threshold levels greater than 10% FSH.




8 Equipment Set up

8.1 General The multi-channel ultrasonic equipment shall be electronically calibrated at least once per 3-month period. This will be carried out according to the applicable RTD in-house Calibration Procedure.

8.2 Setting of Inspection Gates

8.2.1 Pulse Echo and Tandem Channels With each chosen probe (as applicable), positioned for the peak signal response (nominal 80% FSH) from their applicable calibration reflector, the detection gates are to be set. The gate shall start 3-8mm before the theoretical weld bevel preparation. The gate will end nominally 1mm past the weld centreline. The through holes are used to identify the correct end position of set gates. All gates will be programmed to record amplitude and/or transit distance information. The gate length of the transit distance in the root channel will be extended to enable root penetration registration. Gate thresholds levels shall be set below the 40% evaluation level.

8.2.2 Mapping Channels The mapping gates in the body of the weld start 3-5mm (allowance for width of heat affected zone) before the theoretical weld bevel preparation. The gate length will be extended to enable cap reinforcement registration. The chosen element group will be used for detection of porosity. The mapping gate(s) in the Root will be identical to those of the Root pulse-echo transit distance (TD) channel(s); this enables the registration of the Root penetration.

8.2.3 TOFD Channel The TOFD gate start will be set ±3mm before the arrival of the lateral wave and shall extend past the first back-wall echo, to achieve full volumetric examination of the through thickness of the weld. Note: The TOFD gate settings may be altered if geometry indications dictate.

8.3 Sensitivity Settings

8.3.1 Pulse Echo Sensitivity Settings With each chosen element group or conventional probe as applicable, positioned for the peak signal response from its applicable calibration reflector (FBH or notch) the reference sensitivity level shall be set. The reference sensitivity (echo amplitude) for all Pulse-Echo and Mapping channels shall be set at 80% FSH.




8.3.2 Mapping Sensitivity Settings Mapping channels in the body of the weld will be used to detect the presence of porosity and in addition to identify the position of the weld cap reinforcement for pattern recognition purposes. The sensitivity as a minimum is 80% FSH, increased typically with 4-14dB additional gain to ensure proper detection, but should not be so great as to cause interfering electrical or geometric noise that could be misinterpreted. Mapping channels for the Root are equal to the related pulse-echo channel increased typically with 4-14dB additional gain to ensure proper detection, but should not be so great as to cause interfering electrical or geometric noise that could be misinterpreted.

8.3.3 ToFD Sensitivity Settings The sensitivity of the lateral wave of the ToFD channel is set at a nominal 20% FSH (40% FSH un-rectified signal).

8.4 Reference Level Reference level is 80% FSH.

8.5 Scanning Level Scanning level is reference level.

8.6 Evaluation Level (Go-Nogo level) The evaluation level is 40% FSH.

8.7 Probe Selection Refer to specific procedure UT-06566-spec.

8.8 Signal to Noise values in the gated area. To determine the signal to noise value for each probe, the probe will be positioned to detect its calibration reflector at 80% FSH, the gain level will be recorded (initial gain setting).The probe will be moved to a point clear of any calibration reflectors. The ambient noise levels will then be increased to 80% FSH and the gain level recorded. The difference between the two gain settings will be the value recorded as the signal to noise level. 9 Scanning Preparation & Surface Condition Pipe ends should be examined for lamination at the pipe mill / by manual UT method prior to AUT. Spiral welds or long seams must be ground smooth over the scanning area for approximately 100 mm. The scanning area shall be free of weld spatter, FBE coating and other irregularities, which may interfere with the inspection.




When the surface condition prevents or interferes with scanning, the QC Dept and / or the Welding Representative shall be informed. 10 Reference Line After bevelling and prior to welding, a reference line shall be scribed on the pipe surface at a set distance from the centreline of the weld preparation, on the inspection band side. This reference line shall be used to ensure that the band is adjusted to the same distance from the weld centreline as to duplicate the calibration standard. In the event of the reference line being inaccurate or missing, the centre of the weld cap may be used until the problem is rectified. Scribing of the pipe is carried out by contractor (Saipem) personnel, scribe tools and instructions are provided by RTD. 11 Acoustic Coupling Fluid Potable fresh water shall be used as the acoustic coupling fluid and be able to test welds up to 90°C. The coupling is supplied between the probe contact surface and the pipe via supply channels incorporated in the probe housing. To enable good acoustical contact between the ultrasonic probes and the pipe surface, conditions as mentioned under Section 9.0 shall apply. Note: Cooling may be performed with water and the surface rinsed with potable fresh water prior to scanning.

11.1 Coupling Set-up Coupling is set up using the pitch catch technique. Using both Upstream & Downstream probes with identical zonal functions, the sensitivity is established by setting the amplitude height of the signal to 80% FSH with a nominal 12dB gain added. Note: The setting of the coupling sensitivity for each channel shall be completed with the probes placed on the weld to be inspected in the six o’clock position. Coupling Verification: A re-examination of the calibration standard with its surface wiped dry shall produce a record showing a lack of coupling, i.e. absence of recording signal. 12 Examination

12.1 Dynamic Calibration Check The calibration sensitivity shall be verified on the calibration reference piece. Re-calibration shall be carried out if any of the following exist:

• The reference sensitivity values fall outside 65% to 100% FSH. • The gate settings need to be adjusted by more than +/- 1.5 mm from the




previous calibration. • After equipment breakdown. • Before every weld repair scan.

In cases where the calibration differs from the initial setting, outside these given tolerances, the applicable probe(s) and coupling shall be checked. If the calibration has to be changed, the welds before this calibration up to the previous calibration will be re-evaluated taking the differences in the gain and/or gate adjustment into account. The result of each calibration scan shall be printed and stored on the hard drives, each calibration will have the same number as the next corresponding weld with the designation of “c” given as a postfix. Calibrations are performed in the same direction and at the same nominal speed as the weld.

12.2 Calibration Frequency During the first 10 welds a calibration scan shall be made for every inspected weld. Thereafter the frequency of calibration is reduced to a minimum of one calibration every ten welds or every 2 hours. In addition, a calibration shall be made after each shift end.

12.3 Circumferential Scanning Direction The circumferential scanning direction shall be clockwise when viewed from the upstream side of the pipe in the direction of construction. Reverse scanning may only be used where geometry or coating prohibits clockwise scanning. All reverse scans shall be clearly marked in the “comments” section of the Rotoscan program. The encoder accuracy is to be verified following the steps outlined below: 1. Physically measure the pipe circumference 2. Enter the measured circumference into the Rotoscan program. 3. Perform a scan and compare the stop position of the scanner in relation to the 0mm mark on the weld. The difference, if any, shall be within the specified tolerance of +/-10mm. Once verified, add in 100mm for the overlap. 4. During scanning, the functioning of the encoder shall be checked continuously at the end of each scan, checking the end position of the last probe related to the 0mm position.

12.4 Datum Point The zero reference point and the scanning direction shall also be clearly marked on the surface of the pipe and will correspond with the stop-start “top button.”




12.5 Step by Step Description of a Rotoscan Examination Before starting the step-by-step description, the AUT-system has already been calibrated and a calibration scan with a record has been made. 1. Adjust the guiding band on the pipe to the set distance from the scribe line (weld centreline) and parallel to the weld. 2. The Scanner technician will mark the zero reference point at the 12 ‘o clock position on the pipe. (“Top Button”) 3. Attach the scanner to the band. 4. Locate the scanner over the top of the pipe and make sure that all probes are past

the zero point and are in proper contact with the pipe surface. The leading probe, designated as “0mm delay”, will be set so that its probe holder centre hole is aligned with the zero point.

5. Switch on the coupling supply. 6. Switch on the system and automatically the weld will be scanned in clockwise direction. 7. The system and the coupling supply switches off automatically after a full scan with an overlap of 100mm. 8. Check the inspection results for imperfection indications and proper coupling. Use the transit distance recordings and mapping images for validation of imperfection indications within the Root area and proper alignment of the guiding band. In case that a lack of coupling exists exceeding the acceptable limits, refer to Section 11.1.1; a second scan will be necessary. 9. Remove the scanner from the band and attach it to the Reference Standard. 13 Interpretation of Results

13.1 General With the pulse echo transit distance measurements and with the information from the mapping and ToFD channels visible on the result presentation, indications shall be judged whether they are from the weld geometry or defects.

13.1.1 Coupling Criteria The coupling channels will be checked for coupling loss. Loss of coupling in any single pulse echo channel must be compensated for by supplementary inspection channels to maintain full volumetric inspection. “Supplementary inspection channels” include “TOFD” and “Mapping” channels, as well as adjacent pulse echo channels. The maximum length cannot exceed 25mm. Where non-supplemented coupling loss exceeds 12 mm, or lack of coupling occurs at the same circumferential position in two adjacent channels, a rescan shall be performed. This criteria also applies to any “missing data” lost or not recorded during a scan




13.1.2 Lamination Detection Lamination detection will be performed during the inspection scan by using data from the TOFD and coupling channels. Where laminations are suspected or detected a supplementary manual inspection shall be performed on the area and the result documented.

13.1.3 Axial Defect Detection Axially oriented defects are mainly being detected with the TOFD channel. In case of a disturbed back-wall or lateral wave of the TOFD, these should be further investigated to the extent of origin. This can be performed via the PE, Mapping and Coupling channels. If no clear judgement can be made with the AUT data, than other NDT means should be used;

- In case of Lateral wave distortion; MPI inspection should be performed on the outside pipe surface. In case of axial orientated imperfection open- or close to the outside surface should be detected.

- In case of Back-wall distortion; Manual UT should be performed, this should be performed with a 45° angle probe. Cap reinforcement should be ground flush at the applicable location, to the satisfaction of the NDT Operator, for axial scanning on half skip, in case of indications in both directions (CW & CCW) the indication should be treated as an axial orientated imperfection. Imperfection length is determined via the –6 dB drop method in relation to the applicable calibration sensitivity.

13.2 Imperfection Length “Imperfection Length” of an indication will be defined if it has at least one amplitude value equal to or greater than the threshold amplitude. The threshold level is 40% amplitude, i.e. the starting point of the imperfection is located where the signal crosses the 40% amplitude level, the defined imperfection length stops once the amplitude drops below the 40% amplitude.

13.3 Imperfection Height “Imperfection Height” is the vertical (through wall) dimension of the imperfection. The actual wall thickness can be measured with the TOFD. The accuracy of this measurement and/or imperfection height is ± 1mm. The accuracy of the wall thickness measurement shall be checked on the calibration block

13.4 Imperfection Depth “Imperfection Depth” is the through-wall distance to the bottom of the imperfection as measured from the outside surface of the pipe. 14 Determination of Weld Acceptability

14.1 Determine whether Section 9 or Appendix A of API 1104 is applicable Acceptance / Rejection criteria for pipeline girth weld discontinuities shall be to API 1104 20th edition November 2005, section 9.6. Refer to the applicable Specific AUT Procedure.




It shall be determined whether an imperfection is derived from a planar or a crack like type of defect. In case this can not clearly be defined by the Rotoscan DATA result than supplementary Manual Ultrasonic must be used for further evaluation.

14.2 Indications (General) Indications produced by ultrasonic testing may or may not be imperfections. Changes in the weld geometry due to alignment offset of abutting pipe ends; changes in weld reinforcement profile of ID. Root and OD Capping passes; internal chamfering; and ultrasonic wave mode conversion due to such conditions, may cause geometric indications that are similar to those caused by weld imperfections but that are not relevant to acceptability. Review the scan and assess the weld for geometry and imperfection signals.

14.3 If Imperfections Exist Determine Height, Length, and Depth

14.3.1 Imperfection Height Measurement Since API 1104 Section 9.6. is applicable, also imperfection accumulation must be considered as defined in API 1104 Figure A-6 Criteria (Refer to applicable Specific AUT Procedure). The following steps are to be undertaken:

• Imperfections in the near surface area (In this area TOFD is less accurate or not useful, therefore more value is given to the PE result);

- Locate the centre of the imperfection (defect can be present in more pulse echo

channels, use amplitude signature comparison). - Use the probe related sizing curve (pre-set in the software) to measure the

Pulse Echo defect height of the imperfection. - Determine the imperfection length. Use the related PE channel at the specified

Go-Nogo level. - Determine whether the measured imperfection dimension is acceptable to the

specified acceptance criteria. - When imperfection is evaluated to be acceptable, determine whether the

imperfection is interacting with adjacent channels (both circumferential and through wall direction)

- Define the final imperfection dimensions and determine acceptability against the specified acceptance criteria.

Refer to Attachment 4 for the “Decision Flow Chart”.

• Imperfections in the volume and root area; - Locate the centre of the imperfection (defect can be present in more pulse echo

channels, use amplitude signature comparison). - Use the probe related sizing curve (pre-set in the software) to measure the

Pulse Echo defect height of the imperfection.




- Determine whether there are resolvable TOFD diffraction signals available, if yes, determine the imperfection height.

- The TOFD height measurement may overrule the PE measurement. - Determine the imperfection length. Use the related PE channel at the specified

Go-Nogo level. - Determine whether the measured imperfection dimension is acceptable to the

specified acceptance criteria. - When imperfection is evaluated to be acceptable, determine whether the

imperfection is interacting with adjacent channels (both circumferential and through wall direction)

- Define the final imperfection dimensions and determine acceptability against the specified acceptance criteria.

Refer to Attachment 4 for the “Decision Flow Chart”. Height of Cluster porosity For cluster porosity, the TOFD response within the cluster will not return to the normal background grain response. The height of the cluster is determined by measuring the transit distance at the start and end of the cluster within the gate at 40% FSH (above white colour). Out of this distance, the height is calculated taking into account the applicable probe angle. Example ; - probe angle 45º - distance Td1= 5.7mm / Td2= 4.0mm Height is ( 5.7mm-4.0mm ) * Cos 45º = 1.2mm




14.3.2 Imperfection Length Measurement If Section 9 is applicable imperfection accumulation must be considered.

14.3.2.1 Beam Spread Correction Possible overestimating of imperfection length must be considered in interpreting allowable imperfection lengths. Imperfection length may be evaluated as shown in below figure.

14.3.3 Imperfection Depth Measurement Use TOFD, Amplitude or “Inherent pass height” as appropriate. Defect depth location can be pin pointed with TOFD. TOFD will be utilised for this by locating the defect depth (lower tip) and recording the depth from the OD surface. In the event that no signal is seen in the TOFD channel, the defect location will be defined by the reflections that appear in the relating pulse echo channels. The location within the gate will also be taken into account. “Interzonal” imperfections are evaluated differently than “Stacked” imperfections. An “Interzonal” imperfection is defined as a single flaw, which is seen by adjacent channels. To be considered “Interzonal”, the echo dynamics and the circumferential positioning should be the similar. In the case of “Interzonal” imperfections, only the imperfection and not the over-trace of the imperfection are to be sized. Where the echo dynamics differ, the imperfection will be considered larger than the beam or “Stacked” and reported as such.

14.3.4 Repair Marking and Repair Reporting Procedure All repairs shall be marked (start, stop and depth of defect) on the pipe by RTD personnel and a repair indication sheet shall be produced for each repair and handed over to the Saipem Welding Foreman or their delegate.




15 Acceptance/Rejection Criteria

15.1 API 1104 Section 9 Criteria Unless otherwise documented the following will apply : Indications determined to be Cracks (C) shall be considered defects. Imperfections with a vertical height > ¼ wall thickness shall be considered defects. Multiple imperfections at the same circumferential location with a summed vertical height dimension > ½ wall thickness shall be considered defects. Linear Surface (LS) indications (other than cracks) interpreted to be open to the I.D. or O.D. surface shall be considered defects should any of the following conditions exist: The aggregate length of LS indications in any continuous 300 mm length of weld exceeds 25 mm. The aggregate length of LS indications exceeds 8 % of the weld length. Linear Buried (LB) indications (other than cracks) interpreted to be subsurface within the weld and not I.D. or O.D. surface-connected shall be considered defects should any of the following conditions exist: The aggregate length of LB indications in any continuous 300 mm length of weld exceeds 50 mm. The aggregate length of LS indications exceeds 8 % of the weld length. Transverse (T) indications (other than cracks) shall be considered volumetric and evaluated using the criteria for volumetric indications. The letter T shall be used to designate all reported transverse indications. Volumetric Clusters (VC) indications shall be considered defects when the maximum dimension of VC indications exceeds 13 mm. Volumetric Individual (VI) indications shall be considered defects when the maximum dimension of VI indications exceeds 3 mm in both width and length. Volumetric Root (VR) indications interpreted to be open to the I.D. surface shall be considered a defect should any of the following conditions exist: The maximum dimensions of VR indications exceed 6 mm. The total length of VR indications exceeds 13 mm in any continuous 300 mm length of weld. Any accumulation of Relevant Indications (AR) shall be considered a defect when any of the following conditions exist: The aggregate length of indications above evaluation level exceeds 50 mm in any continuous 300 mm length of weld. The aggregate length of indications above evaluation level exceeds 8 % of the weld length. All Rejectable indications will be marked on the Rotoscan Site-Report.




16 Rules for GMAW Repair (s) The AUT scanner shall be used for repair inspection. The AUT scanner shall be calibrated with the applicable calibration standard i.e. wall thickness. No changes shall be made in any of the channel gain settings. Only the area of the originally identified defect shall be interpreted to the applicable Repair Acceptance Criteria. When Re-examination of the repaired weld takes place, the following shall apply:

• Comparison with the original scan to the repaired scan recognising the unique echo dynamic pattern(s), to ensure that the original defect has been removed. • A permanent electronic record is kept of the repaired weld.

17 Reporting The Rotoscan Site-Report will be used for reporting all test results with the following information; • Project and RTD Project Number • Client Name • Inspection Date • Weld No • Rotoscan Equipment Number • AUT Procedure Number • Acceptance Criteria • Diameter • Wall thickness • Material grade • Interpretation of Indication(s): location on circumference-length, depth and height • Accept or Reject • Technician Name and Signature • Any changes in the essential variables as per paragraph 7.6 of this procedure For all rejected weld imperfections as a minimum the circumferential start and stop points, “zonal” location, through wall height, depth & type shall be reported in the Rotoscan Site-Report. For a sample of the Rotoscan Site-Report, refer to Attachment 2. The following set-up for file names will be used during the pipeline project. Examples of file name for weld 1234 ; 1234C Calibration scan performed prior to Mainline weld 1234 Scan of Mainline weld 1234RC Calibration scan performed before scanning the weld repair 1234R Scan of weld 1234 after repair




The AUT Operator can produce a Rotoscan defect print-out highlighting all specific details of a reported imperfection of defect. He will produce such a print-out at request of QA/QC and/or the welder foreman. Refer to attachment 3 for an example Rotoscan Defect info print-out. 18 Storage of Data The raw data of each inspected weld will be stored on the main hard drive (C Drive). In addition, a back up will be made on a second hard drive (Removable D Drive). The Date and Time function will be used to insure that all welds scanned are accounted for. By selecting this function the date and time of each scan made becomes part of the file name, removing the chance of overwriting any file. Welds will be stored in daily directories, which will be created at 24:00 hrs each day. Operators are responsible for the daily directory on the main hard drive and shall insure that all welds are present and readable. Each shift will store scans and calibrations in a windows folder of that date e.g. 27112006 All calibration and weld inspection results will be printed in a compressed black-white image of the entire weld circumference after acceptable scan is completed. After completion of the pipeline project, all data will be stored on a DVD and presented to Saudi Arabian Saipem Ltd. The official record of inspection will be the Rotoscan Site Report and will bear the original signature of the AUT Rotoscan Operator.




Attachment 1 - Example of AUT Frame Configurations

Scanning direction

( DS – side )

Z4 HP DS

Z5 Root DS

Z2 Fill DS

Z3 Fill DS

ToFD

DS

Z1 Cap DS

Z4 HP US

Z5 Root US

Z2 Fill US

Z3 Fill US

ToFD

US

Z1 Cap US




Attachment 2 - Example Rotoscan Site Report







Attachment 3 - Example Rotoscan Defect info print-out




Attachment 4 - Decision Flow Chart