Detection and quantification of detrimental conditions in HDPE using ultrasonic phased array [PE]

For over thirty years, the gas distribution industry has installed High-Density Polyethylene (HDPE) piping. More recently, the nuclear power industry has also installed HDPE in both safety-related and non-safety-related systems. Both industries have recognized the benefits of HDPE such as extended service life with minimal maintenance, and cost savings over other materials such as carbon steel for the same application. Due to recent nuclear installations, volumetric examination techniques to ensure butt-fusion joint integrity have been evaluated. This paper investigates development efforts to date using ultrasonic Phased Array to detect and quantify flaws and detrimental conditions in butt-fusion joints throughout the applicable pipe diameters and wall-thicknesses. This technology can be applied to both gas distribution and nuclear power applications. Factors addressed will include pipe diameter, wall-thickness, fusing temperature, interfacial pressure, dwell (open/close) time, and destructive correlation with ultrasonic data.