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Plastic pipe inspection in New Caledonia with PolyTest™

TWI carried out a two-phase project – first delivering plastic welding training, then providing plastic pipe inspection – for a pipeline and geomembrane specialist on an island in the South Pacific.

Eau & Environment (E&E) is a company specialising in plastic pipeline and geomembrane installation on New Caledonia, a French overseas territory located 750 miles off the eastern coast of Australia.

A TWI welding trainer first travelled to the island in 2014, to provide plastic welding training to E&E’s technicians. The following year E&E won a contract to install 3.6km of 800mm-diameter polyethylene (PE) pipeline, to serve as a production water marine outfall for a local ore refining company. The company contacted TWI to commission plastic pipeline inspection services. TWI made the 10,000-mile journey, equipped with its PolyTest plastic pipe inspection system.

PolyTest™ is a new field inspection system for volumetric non-destructive testing (NDT) of electrofusion and butt fusion joints in PE pipes. It combines phased array ultrasonic testing (PAUT) technology with novel hardware solutions to meet the challenges presented by in-situ inspection of plastic pipe joints.

Work programme

The inspection was carried out over six weeks and covered ten pipe strings, each containing between 14 and 18 butt fusion welds.

The E&E welding team worked in conjunction with a second sub-contracted weld team to increase weld production rates. The welding took place on the island’s coastline. As welds were completed, each string was incrementally moved toward the water’s edge, where concrete ballast blocks were fitted before the pipeline was floated out to sea. TWI used PolyTest to carry out NDT on the welds as they were completed. Unpredictable weather led to highly variable weld production rates, ranging from three to 18 welds per day.

Despite the challenging conditions, with temperatures of around 30°C and intermittent heavy rain, PolyTest performed excellently. It provided invaluable data, providing assurance of the pipeline’s integrity before it was deployed.

Noumea work site
Noumea work site
PolyTest scanner system
PolyTest scanner system
Phased Array scan data
Phased Array scan data
Pipe strings ready for movement to installation site
Pipe strings ready for movement to installation site

PolyTest’s multi-link scanner enables the system to accommodate a variety of pipe diameters while maintaining a simple manual movement that is easily controlled by the operator under varying conditions, providing consistent phased array scan data.

The scale of the project can be seen in this video on the website of the main contractor, Canstruct.

To find out more about PolyTest and TWI’s plastic pipe inspection services, please email contactus@twi.co.uk.

Avatar Doug Wylie Team Manager – NDT Products

Following a 23-year career in the RAF, Doug joined TWI in January 2008 as NDT Programme Manager, Training and Examination Services, responsible for the delivery of the non-destructive testing (NDT) training across four venues in the UK. In October 2011, after completion of a BEng (Hons) degree through the Open University, he transferred to the NDT Section.

Doug, an Incorporated Engineer and multi-method NDT Level 2/3, has experience across a variety of industry sectors. He has been involved in NDT application both on- and offshore, third-party inspection witnessing, procedure development and review, collaborative projects and single-client project support. As a team manager he is now responsible for developing the delivery of NDT products in TWI’s Integrity Management Group, and is also leading the innovation project ‘PolyTest’, a new system for inspecting welded joints in HDPE piping.

Away from TWI he is chair of the BINDT Membership, Qualification & Education Committee and sits on BINDT Council.

For more information please email:


contactus@twi.co.uk