To evaluate the condition of the carbon-steel annular ring of a storage tank from the outside using an automated long-range ultrasonic test.

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1 Page 1 of 5_ ISO 9002 Document Doc. No _572 1 PURPOSE To evaluate the condition of the carbon-steel annular ring of a storage tank from the outside using an automated long-range ultrasonic test. 2 LIMITATIONS The method uses a long-range ultrasonic technique to evaluate corrosion damage to the annular ring/floor extension and tank floor within 0.5metre of the tank wall. This method is qualitative, and gives indications and their plan position, it does not provide quantitative information. Indications are compared with a test plate in order to evaluate their severity. The standard test plate has 50% through slots at 100mm, 200mm, and 400mm from the probe, and indications are normalised and graded relative to this (i.e. above/below that amplitude level). It should be noted that the method is most sensitive to rapid change in section, and is insensitive to slow changes in section The scanning device used runs on the tank wall adjacent to the annular ring; this requires the lower 0.5 metre of the tank to be free of obstructions. This requires lagging to be removed from insulated tanks. Note, the maximum shell temperature of heated tanks must be <80 0 C A minimum of 50mm protruding plate (chime) is required for the ultrasonic probe to make contact. The probe side surface (upper surface of the annular ring plate) must be prepared, heavy rust deposits, loose scale and nonadherent coatings to be removed. Poor surface results in loss of signal and may reduce sensitivity to zero Circumferential scan speed is ~5mm per second at 1mm resolution. Productivity of 40 metres per day has been achieved.

2 Page 2 of 5_ ISO 9002 Document Doc. No _572 3 PROCEDURE 3.1 Preparation Return completed information form to PAL (see Appendix 1) indicating the number, location and length of scans Prepare annular ring as described (in paragraph 2.1.2) and remove obstructions from lower 0.5 metre of tank wall in area of inspection. This includes removing any insulation from the lower 0.5 metre of tank wall in the area of inspection. 3.2 Test Electrical supply to the instrumentation (220/240V, 16A) is provided by generator or mains supply. (PAL by prior request) Water supply for ultrasonic scanning system, either storage drums (45 litre) or mains supply. (PAL by prior request) Suitable vehicle (van or pick-up) required to carry water drum, instrumentation and tow portable generator. This is especially needed for round-tank inspections as standard umbilical cable is only 20 metres. (PAL by prior request) PAL may require help to run cables and move generator/equipment. (PAL usually provides one engineer only).

3 Page 3 of 5_ ISO 9002 Document Doc. No _ Reporting A brief site report will be issued highlighting the areas where there are indications Any deviation from standard procedure that is required is discussed with the customer and this discussion must be acknowledged by signature on the quality plan. Action: PAL/client The final report, with test results on compact disc (CD) in the form of images and/or Excel spreadsheets approved by a PAL level III Engineer, is issued within 4 weeks. Where a written report is requested, this will normally contain only the details of the test and images of those scans showing indications. Where printed images are required for all scans there will be an extra charge dependent upon the extent of work. Action: PAL Shell: 100mm 200mm 400mm Plan view scan of calibration plate showing slots at 100, 200, and 400 mm.

4 Page 4 of 5_ ISO 9002 Document Doc. No _572 4 QUALITY CONTROL 4.1 Work is carried out to standard documented procedures, using field worksheets as a test record, and a quality plan, signed by the engineer and customer, at the appropriate stages, according to PAL ISO 9002 procedures. The digital images act as a further quality record and are archived accordingly. The raw rf inspection data will be retained long term only upon customer request due to the large file sizes involved (~25MB/metre). 4.2 PAL engineers are certified to level II or higher in ultrasonic testing (UT), according to ASNT-TC-1A (or equivalent) and PAC written practice. This certification involves theory and practical examinations. Other certification schemes by request. 4.3 All work is reviewed at PAL, and approved by a PAC level III experienced in the procedure. Level III support is available as required.

5 Page 5 of 5_ ISO 9002 Document Doc. No _572 Appendix 1 TA-LRUT BACKGROUND INFORMATION REQUEST Customer: Location: Contact: Telephone: Fax: Tank N o : Diameter: Year Built: Insulated: Yes / No (see paragraph limitations) Contents of tank: dry / product / cleaned External coating type: Internal coating type: Annular Plate nominal thickness (mm): If product, type: Thickness of coating: Thickness of coating: Areas to be Inspected: Please annotate areas to be inspected on diagram. Show any pipelines, man-ways etc. this will help accurate location, show length of each scan. Special Notes, Repairs and Concerns: On-Site Requirements and Limitations: Signature: Detailed in paragraphs 2 & 3 of this Method Statement. Digital images are archived long-term, raw rf data saved long-term only on request: yes/no