Production of Flawed Butt Fusion Joints in PE Pipes for the Evaluation and Qualification of Ultrasonic NDT Systems
Status: Project
Date Announced: November, 2025
Project reference: 313463
Summary
The industrial interest and use of ultrasonic non-destructive testing (NDT) of butt fusion (BF) joints in polyethylene (PE) pipes is rapidly gaining momentum, due to the publication of the ISO Technical Specifications ISO/TS 22499 and ISO/TS 24399, and the increasing number of companies providing such as service.
However, the ultrasonic inspection of PE pipe joints is very different to the inspection of metallic pipe joints. The attenuation of the ultrasonic signal is much greater in PE than in metals, the velocity of the ultrasound is much slower and the types of flaws are very different to those found in metal joints. This means that ultrasonic NDT systems used to inspect metallic pipe welds will not work on PE pipes; the ultrasonic probes, wedges, manipulators and procedures have to be designed specifically for non-metallic pipes.
For the pipeline owners, it can be difficult, and costly, to assess the performance of any particular NDT provider. The procedure for qualifying NDT procedures in ISO/TS 22499 and ISO/TS 24399 involves making 21 BF joints for each of four pipe wall thicknesses ranges. Five joints should contain no flaws and are used by the NDT provider to set up their equipment and procedures. 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 cost-ineffective 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. It is therefore more efficient for there to be a central library of flawed joints that companies can borrow as and when they need.
TWI is a world leader in the insertion of flaws into welded joints in PE pipes in a consistent manner and wrote the flaw insertion procedures given in the annexes of the ISO Technical Specifications. TWI is therefore ideally placed to create and hold this library of flawed joints.
Objective
Produce a library of flawed BF joints in PE pipes, according to the procedures given in ISO/TS 22499 and ISO/TS 24399, for use by the Sponsors to assess ultrasonic NDT systems.
Benefits
The most cost-effective way for the PE pipe industry (pipe manufacturers, pipeline installers and end users) to assess and qualify any ultrasonic NDT system.
Can be used by NDT companies to assess their own ultrasonic inspection systems.
If you are interested in finding out more, download the PDF Summary Outline using the following link.