APPROVAL AND REJECTION CRITERIA FOR PHASED ARRAY ULTRASONIC TESTING ON PE ELECTROFUSION JOINTS

Speaker:
Roelofs, Bart; Alliander NV; Netherlands

Authors:
Roelofs, B.; Liandon; Netherlands
Kuiphof, J.; Liandon; Netherlands

ID: ECNDT-0064-2018
Download: PDF
Session: Civil Infrastructure 2
Room: J1
Date: 2018-06-11
Time: 15:40 - 16:00

Polyethylene (PE) is a commonly used material for the construction of new gas grids. The construction of new gas grids inevitably involves making many joints. For PE pipe systems, electrofusion is a common technique to create joints. Due to human and machine errors, it’s possible that joints contain errors. In order to ensure that new gas grids are of good quality, sufficient testing of joints is essential. At the moment in the Netherlands, approximately 10% of newly installed joints are being removed in order to test them destructively.

Over the last three years, Alliander researched the applicability of Phased Array Ultrasonic Technique (PAUT) on PE electrofusion joints. Meanwhile, more than 200 joints have been randomly chosen and investigated by using this technique. This research has led to the following conclusions:
1. PAUT is applicable on PE joints in the trench;
2. It’s possible to detect deviations in the PE joints;
3. By giving direct feedback to the welder, the quality of the joints improve.

Moreover, the experience gained during these last three years led to a set of rejection and approval criteria. The criteria are based on previous research, standards and Dutch regulations. This paper describes and explains the rejection and approval criteria for testing PE electrofusion joints by using PAUT.

Project partners: Liander, Liandon