Summary on Technology

In-service robotic tank inspection is a proven technology incorporated in American Petroleum Institute Standards (API 653 , API RP 575)

API 653 Reference (Section 6.4.1.2)

6.4.1.2 All tanks shall have a formal internal inspection conducted at the intervals defined by 6.4.2. The authorized inspector shall supervise or conduct a visual examination and assure the quality and completeness of the nondestructive examination (NDE) results. If the internal inspection is required solely for the purpose of determining the condition and integrity of the tank bottom, the internal inspection may be accomplished with the tank in-service utilizing various ultrasonic robotic thickness measurement and other on-stream inspection methods capable of assessing the thickness of the tank bottom, in combination with methods capable of assessing tank bottom integrity as described in 4.4.1

API 575 Reference

As Per API Recommended practice 575 section 6 It is stated that “API Std 653 recognizes the proper use of alternative inspection methodologies. For example, robotic inspection is one possible approach to achieve an assessment of the tank bottom and other internal members without personnel entry.” Further in API RP 575 Appendix A (Selected Non-Destructive Examination Methods) part A.5 it is mentioned that Robotic inspection is one of the recommended practises for storage tank inspection. In API RP 575 Section 7.4.4 the number of measurements taken for a statistical sampling will depend on the size of the tank and the degree of soil-side corrosion found. Typically, 0.2% to 10% of the bottom should be scanned randomly. The collection of thickness data is required to assess the remaining bottom thickness.