Ultrasonic Testing (UT) is to be carried out according to a procedure based on ISO 17640 (testing procedure), ISO 23279 (characterisation) and ISO 11666 (acceptance levels) or other accepted standards, and specific requirements in this chapter. When ultrasonic inspection is to be used as an inspection method at a shipyard, the Surveyor is to be satisfied with the yard’s capability with this method. Several important considerations which are to be investigated are the yard’s operator training and qualifying practices, reliability and reproducibility of results and the proper application of approved procedures, and acceptance standards. Where a yard desires to use ultrasonic inspection as the primary inspection method, such testing, at the Surveyor’s discretion, is to be initially and periodically supplemented or complemented with random radiographic inspections to verify the adequacy of the quality control system.