Ultrasonic technician performance test for boiler tube thickness measurement, Technical Information Paper TIP 0402-21 (2018)

This procedure has been developed by a TAPPI Task Group to offer a basis for evaluating the skills of technicians who measure the thickness of boiler tubes from the external surface using manual instruments. Use of this procedure is prudent when thickness testing recovery boiler tubes, where high reliability is important to avoid a potential smelt-water reaction and explosion from a water leak. The evaluation includes a background interview of each technician, as well as an operative test to objectively determine the technician's ability to accurately calibrate an ultrasonic thickness unit and measure a boiler tube test panel. This procedure is written for bare carbon steel tubes but can be applied to other materials if representative test panels are prepared (e.g. chromized, composite, weld overlaid). Specialized ultrasonic test equipment, such as semi-automated scanners, could be addressed by appropriate modifications to this procedure.