Mon, 11 May, 2026
TWI is holding a launch meeting for a new project concerned with the production of flawed butt fusion joints in polyethylene (PE) pipes for the evaluation and qualification of ultrasonic non-destructive testing (NDT) systems.
There is a growing interest in the use of ultrasonic NDT of butt fusion PE pipes, in part driven by the publication of ISO Technical Specifications ISO/TS 22499 and ISO/TS 24399, as well as the increasing number of companies providing such a service.
However, ultrasonic PE pipe inspection differs from the inspection of metallic pipe joints as the ultrasonic signal is much greater in PE than with metals, the ultrasound velocity is much slower and the types of flaw are different from those found in metal joints. This means that the ultrasonic probes, wedges, manipulators and procedures have to be designed specifically for non-metallic pipes.
The assessment of a given NDT provider can be difficult and costly for pipeline owners as the procedure for qualifying NDT procedures in ISO/TS 22499 and ISO/TS 24399 involves making 21 butt fusion joints for each of the four pipe wall thickness ranges. Of these, five joints should contain no flaws and are used to set up the equipment and procedures, while the remaining 16 joints are used for blind inspections. Eight of these contain no flaws, two contain embedded lack of fusion flaws and six contain fine particulate contamination.
The production of these joints is expensive, which makes it costly for individual companies to produce such a set of joints, especially if they need to cover the whole pipe wall thickness range from 8-100mm, which would require the manufacture of 84 joints. To save on costs, TWI has proposed the creation of a central library of flawed joints that companies can borrow as they need.
TWI is the perfect organisation to deliver this, given our history as a leader in the consistent insertion of flaws into welded PE pipe joints. Our experts also wrote the flaw insertion procedures given in the annexes of the ISO Technical Specifications, making us ideally placed to create and hold this library of flawed joints.
You can find out more about the launch meeting, taking place on 2 June 2026 and the project itself, here:
https://www.twi-global.com/media-and-events/events-diary/production-of-flawed-butt-fusion-joints-in-pe-pipes