Peter Postma & Hermkens René
# 2012 Barcelona
The suitability of non destructive techniques for testing polyethylene pipe joints are
investigated in a GERG (European Gas Research Group, www.gerg.eu) project. The
results show that :
• Both Ultrasonic and Microwave techniques have developed to a mature level.
• For electrofusion joints good results are obtained with Ultrasonic Phased Array techniques. These techniques are ready for practice, and in some cases already applied as such.
• For butt fusion joints CHORD Ultrasonic testing is showing good results, but this method is only tested to a limited extent in this project. Both Ultrasonic TOFD and Microwave techniques show some indication on the joint quality but both techniques need further development.
• The Bead Bend Back test that is used in the UK to examine butt fusion joints shows good results. This technique is quite simple and can be considered as an NDT technique as well The different techniques have been assessed on their maturity and suitability to be used in practice. The techniques have been tested on both laboratory made joints and excavated joints, about 180 different joints in total. The laboratory joints are a mix of good joints and joints with certain type of errors introduced deliberately. The joints have been sent to NDT companies for blind testing (without any knowledge about the introduced errors). Afterwards the joints have been destructively tested in accordance with ISO standards. The results of the Non Destructive Techniques have been compared with the introduced errors and the results of destructive tests . This GERG investigation shows the possibilities and performance of current techniques, and what further steps need be to taken to use the techniques in practice.