Marine Terminal Wastewater HDPE Joint Welding Testing
Marine Terminal Wastewater HDPE Joint Welding Testing | San Diego, California
DPSI performed Nondestructive Examinations (NDE) of High-Density Polyethylene (HDPE) piping fusion welds located at maritime docks in San Diego, California. Due to the high levels of risk and safety concerns using radiographic testing, the client requested we provide an alternate ultrasonic method. The method DPSI provided was Time-Of-Flight-Diffraction (TOFD).
The HDPE piping is being used to replace old cast iron lines that remove sewage from large ships and freighters at the docks. The piping is being introduced to sea water and sewage wastewater which make for a highly corrosive combination, internally and externally. HDPE was chosen for its high resistivity to this corrosive environment. Ultrasonic TOFD examination of fusion joints is an easily employed NDE tool that is used to provide assurance of fusion-joint integrity. Lack-of-fusion, cold fusion (partial bond), inclusions (embedded) and voids are the typical flaws that occur and are detected in the HDPE fusion weld process.
Before the TOFD examination process, the client planted a practical test coupon in a batch of 10 identical coupons to verify detection of non-fusion. TOFD was able to detect 7 of 7 drilled holes that were placed within a single fusion face.
All permanent joints were tested with no flaws detected for repair. This ultrasonic method allowed for all neighboring construction crews to continue their tasks without downtime and enabled the contractors to finish the project before the deadline.