SHELL CORROSION MAPPING TANK No: T1234

Report No: XXXX

Test Date: May 2009

Client: Client

Client order No.: Order No

PAL contract ref.: D0xxxx

Asset Location: Client site

Test Engineer: A. Engineer

UT Level II (PCN: 301xxx)

Reviewed by: B. Engineer

UT Level II (PCN: 301xxx)

Approved by: P T Cole

MHG Level III

Report No. FTxxxx Tank T1234

CONTENTS

1. INTRODUCTION AND BACKGROUND 2. TEST PROCEDURES 3. LIMITATIONS 4. RESULTS 5. SUMMARY TABLE OF RESULTS 6. THICKNESS DISTRIBUTIONS 7. FIGURES 8. TANK and TEST DATA

Report No. FTxxxx Tank T1234

1. INTRODUCTION AND BACKGROUND

This report describes work carried out on site and concerns the measurement of wall thickness using the Physical Acoustics LSI automated scanner. LSI is an automated ultrasonic mapping system with a 500mm wide bridge that is operated via an umbilical 20-50 metres long. LSI can climb tank walls by virtue of its magnetic tractors. The measurement result is shell thickness as a function of position for the areas scanned, and may be provided in pure numerical form (e.g. excel compatible files), as colour coded maps, or as a composite image comprising many scans. Unique benefits of the LSI system are its high speed, and its ability to obtain measurement data at critical points such as the weld heat affected zone, which is often subject to selective corrosion, and to obtain data on poor surfaces. The purpose of the measurement is to establish tank shell condition in order to help make decisions on tank maintenance timing and priority. 2. TEST PROCEDURES

All testing is carried out to standard Physical Acoustics Limited standard procedures, (ISO document number 652 current issue), the field worksheets (Doc.654) are kept as a quality control record together with the digital test data, plus an overall quality plan (Doc.653) for the individual tank, according to PAL ISO 9001:2000 procedures. Engineers are trained specifically in these procedures, as well as in operation of the LSI system. Data and measurement results for the tank are detailed in the results, figures and appendix. Typical tank shell corrosion mapping practice for smaller tanks is to carry out a scan at each of the four compass points, each scan being 250-600 mm wide and nearly the full height of the tank (subject to access). Larger tanks typically have an extra four scans in between those detailed above. Measurement position resolution used is typically 2-10 mm on the scan axis, and 5-10 mm on the index (forward) axis, though the system will work at 0.2-600 mm. Thickness measurement resolution is ~0.1mm. The exact specification for the measurements reported here was determined by the client based upon requirement and cost; the details are given in the test data section. 3. LIMITATIONS

The method is ultrasonic, and as such is limited by the probe used to a minimum thickness, typically 2-5mm depending upon probe, surface finish, and thickness range being measured. Depending upon surface, some measurement points may be missed. Measurement is not possible where the surface cannot be “wet” by the water jet coupling medium, for example if oil or other waxy deposits are present on the surface. Whilst average paint thickness may be used to correct the overall measurement data, on a point to point basis it is not practical to correct for the coating thickness. Plate lamination prevents thickness measurement at that point.

Report No. FTxxxx Tank T1234

4. RESULTS

4.1 Details of the measurements are given in the test data section. A summary of the results for each strake for each scan is given in the summary table. In the figures section the collection of all four scans for each strake are shown with the colour coded scale for thickness. Where full numerical results are provided in excel these are supplied separately on CD. Distribution analysis and composite images are extra cost analysis and reporting options.

4.2 General Measurement Observations: None

4.3 Erroneous data identified in the scans: On weld caps, loss of signal due to uneven surface. This is displayed in red and black dots. Black points can also be the result of bad paint (no signal transfer). All red points and lines are due to erroneous data. Poor water (couplant) quality resulted in erroneous results in other areas all well. These are shown in white.

4.4 Scan details:

Four (4) vertical scans were completed on Plate 1, 4, 6 and 9. Four (4) horizontal scans were completed at course 4 on Plate 1, 4, 6 and 9. One (1) horizontal scan was completed at course 5 on Plate 10 above ladder. These scans continued to the highest possible (accessible) level.

Scan on Plate 1 : Scan start : 2400m from right weld.

Scan on Plate 4 : Scan start : 8100m from right weld.

Scan on Plate 6 : Scan start : 8400m from right weld.

Scan on Plate 9 : Scan start : 8700m from right weld.

Report No. FTxxxx Tank T1234

5. SUMMARY TABLE OF RESULTS

Scan at

P1

P4

P6

P10

Course

Nominal 6.40 6.40 6.40 6.40

Average n/a n/a n/a 7.05

Minimum n/a n/a n/a 5.85 (0.22%)

6

Nominal 6.40 6.40 6.40 6.40

Average n/a n/a n/a 5.13

Minimum n/a n/a n/a 3.73 (1.37%)

5

*Course 5 & 6 scan at plate 10 above the stairway.

Scan at P1 P4 P6 P9 Course

Nominal 6.40 6.40 6.40 6.40

Average 5.12 4.90 4.76 4.96

Minimum 2.98 (0.53%) 2.79(0.36%) 2.95 (1.00%) 3.12 (1.67%)

4

Nominal 8.30 8.30 8.30 8.30

Average 7.02 7.27 6.97 6.76

Minimum 5.33 (0.22%) 5.45 (0.19%) 5.31 (0.91%) 5.25 (0.89%)

3

Nominal 10.60 10.60 10.60 10.60

Average 10.69 10.58 10.66 10.68

Minimum 9.57 (0.22%) 9.44 (1.34%) 9.32 (0.20%) 9.70 (1.57%)

2

Nominal 13.10 13.10 13.10 13.10

Average 13.73 13.67 13.54 13.62

Minimum 13.09 (1.96%) 12.91 (2.29%) 12.32 (0.20%) 12.80 (0.57%)

1

Corrosion allowance from general assembly drawing Drawing No is 0.8mm. Figures in red represent thicknesses below the corrosion allowance. The percentage of scan area at the minimum thickness is also shown.

Report No. FTxxxx Tank T1234

T7701 (P1)

(mm) (P4) (mm)

(P6) (mm)

(P9) (mm)

Course

Nominal 6.40 6.40 6.40 6.40

Average 4.58 4.73 4.67 4.72

Minimum 2.97 (1.00%) 3.30 (0.38%) 3.30 (0.20%) 2.94 (0.30%)

4

*Course 4 Horizontal Scans 5000mm at plate 1, 4, 6 and 9.

T7701 (P1) (mm)

(P4) (mm)

(P6) (mm)

(P10) (mm)

Course

Nominal 6.40 6.40 6.40 6.40

Average n/a n/a n/a 6.35

Minimum n/a n/a n/a 3.32 (0.48%)

5

*Course 5 Horizontal Scans 5000mm at plate10 above the stairway. Corrosion allowance from general assembly drawing Drawing No is 0.8mm. Figures in red represent thicknesses below the corrosion allowance. The percentage of scan area at the minimum thickness is also shown.

Report No. FTxxxx Tank T1234

6. Thickness Distributions

Plate 1, 4, 6 and 9 of course 1 scans.

Plate 1, 4, 6 and 9 of course 2 scans.

P1C1 P4C1

P6C1 P9C1

P2C1 P4C2

P6C2 P9C2

Report No. FTxxxx Tank T1234

Plate 1, 4, 6 and 9 of course 3 scans.

Plate 1, 4, 6 and 9 of course 4 scans.

P1C3 P4C3

P6C3 P9C3

P1C4 P4C4

P6C4 P9C4

Report No. FTxxxx Tank T1234

Plate 10 of course 5 scans. Plate 10 of course 6 scans.

P10C5 P10C6

Report No. FTxxxx Tank T1234

7. FIGURES

Collection of all four scans for each strake with the colour coded scale for thickness. All scans start from top to bottom.

Figure 1. Course 1 – All scans from left to right. Plate 1, 4, 6 and 9 respectively

Figure 2. Course 2 – All scans from left to right. Plate 1, 4, 6 and 9 respectively

Report No. FTxxxx Tank T1234

Figure 3. Course 3 – All scans from left to right. Plate 1, 4, 6 and 9 respectively

Figure 4. Course 4 – All scans from left to right. Plate 1, 4, 6 and 9 respectively

Report No. FTxxxx Tank T1234

Figure 5. Course 5 – Above ladder scan at plate 10.

Figure 6. Course 6 – Above ladder scan at plate 10.

Report No. FTxxxx Tank T1234

Figure 7. Course 4 – Horizontal scans 5000mm. Plate 1, 4, 6 and 9 respectively. All scans from right to left.

Plate 1, 4, 6 and 9 of course 4 horizontal scans.

P1C4H P4C4H

P6C4H P9C4H

Report No. FTxxxx Tank T1234

Figure 8. Course 5 – Horizontal scans 5000mm. Plate 10 above ladder. Scan from right to left. Plate 10 of course 5 horizontal scans

P10C5H

Report No. FTxxxx Tank T1234

8. TANK and TEST DATA

Tank No. : T1234 Diameter: : 29.02m

Contents: : Light Slop Height: : 13.67m

Date of test: : May 2009 Duration: : 1 day

Client: : Client

Client order No. : Order No

PAL contract ref: : D0xxxx

Asset location: : Client Site

Asset owner: : Client

Responsible test eng: : A.Engineer

Certification: : UT PCN Level II

Test system I.D.: : FSI-4

UT probe and SN: : Focussed Probe 5 MHz – 0111B1

Water path: : 1”

Index resolution: : 15 mm

Scan resolution: : 4 mm

Scan width: : 450 mm

Number of scans: : 4 locations – Plate 1, Plate 4, Plate 6 and Plate 9

Colour palette: : 16 colour

DAC details: : N/A

Gain: : 22 dB

MSPS: : 100

Filter: : 2.0 – 12.5 MHz

SET file name: : Course1.set, Course2.set, Course3.set, Course4.set

Course5.set and Course6.set

Calibration: : PAL Calibration Blocks 5mm and 10mm.