Formal Internal Inspection Guidelines Amendment 0003.docx

Formal Internal Inspection Guidelines

1.1 General

1.1.1 FII are to be performed by Certified Inspectors per STI SP001 requirements.

1.1.2 The following paragraphs describe bare minimum inspection guidelines. There are numerous AST configurations and components; it is the responsibility of the Certified Inspector to identify and properly inspect them to conform to the owner’s requirements and/or industry standards. The inspector or the inspection company shall develop detailed checklists that identify, record, and document all aspects of each inspection.

1.1.3 An FII includes the requirements of an FEI with the addition of the requirements described below.

1.1.4 For elevated ASTs where all external surfaces are accessible, the internal inspection requirements may be satisfied with an examination from the exterior by using such methods as UTS. For all other situations, entry into the interior of the AST is necessary to assess the condition of all surfaces.

1.2 Horizontal AST Internal Inspection

1.2.1 Identify, measure, inspect, and record all AST internal appurtenances. Inspect for mechanical damage, corrosion, cracking, ect. Inspect for deteriorating or corroding internal attachments or piping. Take thickness readings of internal structures and record the readings.

1.2.2 Inspect the welds for cracking by visual inspection or, if necessary, by magnetic particle (MT) inspection or equivalent method.

1.2.3 Internal NDT Inspection

1.2.3.1 Ultrasonic testing equipment that is capable of scanning the tank (UTS) rather than measuring only individual points (UTT), is the preferred method of testing. Personnel performing UTS are to be qualified per STI SP001 requirements. If ultrasonic testing equipment that is capable of scanning the tank is not practical, use equipment that tests individual points. In this case, take UTT measurements of at least 15 points per each 12”x12” (0.3x0.3 meters) square area of the shell that is in contact with the ground. Any questionable areas are to be assessed by UTS.

1.2.3.2 Perform a vacuum box (VB) examination of questionable welds to check for leaks.

1.2.3.3 Refer to STI SP001 criteria for suitability for continued service.

1.3 Vertical and Rectangular AST Internal Inspection

1.3.1 Identify, record, inspect, and measure all AST internal surfaces and appurtenances. Inspect AST internals to check for mechanical damage, corrosion, cracking, ect. Check for deteriorating or corroding internal attachments and piping. Take thickness readings of internal structures and record the readings.

1.3.2 Inspect the welds for cracking, corrosion, or incomplete fusion which may result in a leak by visual inspection. If additional investigation is needed, the weld may be tested using vacuum box (VB) or if necessary magnetic particle (MT) or liquid dye penetrant (DPT) inspection or equivalent method.

1.3.3 Internal NDT Inspection

1.3.3.1 AST floor thickness assessments is required as follows:

Complete coverage of the AST floor is recommended, due to random corrosion characteristics of metal in contact with the ground. Inspection of the AST floor is recommended using inspection methods capable of determining the underside floor condition, such as UTS, MFL followed by UTS of questionable areas, or other equivalent methods.

If ultrasonic testing equipment that is capable of scanning the tank is not practical, use equipment that tests individual points. In this case, take UTT measurements of at least 15 points per each 12”x12” (0.3x0.3 meters) square area of the shell that is in contact with the ground. Any questionable areas are to be assessed by UTS.

1.3.3.2 Perform a vacuum box (VB) examination of questionable welds to check for leaks.

1.3.4 Refer to STI SP001 criteria for suitability for continued service.

1.4 Additional requirements for field-erected ATSs are included in Appendix B.

1.5 Report – in the final report; include field data, measurements, pictures, drawings, tables, and an inspection summary. Identify in the summary unacceptable conditions and recommended and/or mandatory corrective actions. Determine the suitability for continued service of the AST per Section 10.0 and document this in the final report. Include the date of the next scheduled Formal External and or FII, as applicable. Include the inspector’s name and certification number in the report.