As the surfaces of the Chimneys are usually will be having thick scaling and unevenness, it may not be suitable to carryout direct Ultrasonic thickness gauging and may require to be grinded /polished with emery for better even surface to get consistent and reliable thickness measurement results before thickness measurement.Calibrated Ultrasonic thickness gauging shall be used for all the applications.
ASTM E797 - Procedure for Measuring Thickness by Manual Ultrasonic Pulse-Echo Contact Method can be used for this application. Ultrasonic thickness gauge shall be calibrated every time before use and after use with the master block provided by the Ultrasonic equipment supplier.
Probes are available for room temperature and elevated (high) temperature application similar measuring the wall thickness of boiler pipes and tubes. Its a mandatory requirement by the statutory bodies to ensure that the pressure vessels, boilers and other critical assemblies needs in-service inspection to find the extent of corrosion.
The personnel qualified and certified to ASNT SNT TC 1A Level I, II requirements can be suitable to perform this NDT inspection technique (Ultrasonic thickness gauging).
Read more about Trinity NDT Ultrasonic thickness gauging facilities, NDT training and certification at our webpage: http://www.trinityndt.com/services_ut.php