A number of Non-Destructive Testing (NDT) techniques have been investigated over the years for inspecting electrofusion (EF) joints, including radiography, thermography and ultrasound. Radiography has been demonstrated in the laboratory as having potential, but it is not well suited for use in the field and thermography has only been capable of detecting gross flaws.
The state-of-the art for volumetric inspection of EF joints is by using Phased Array Ultrasound Testing (PAUT). This technique has been shown to be capable of detecting all common defects in EF joints, including lack of fusion, particulate contamination, pipe under-penetration and cold welds. TWI is a world-leader in PAUT of electrofusion welds in PE pipes and has developed the PolyTest system, specifically for inspecting welded joints in PE pipes.