Pipeline NDT Inspections

Hunua 4 Watermain Project


This large infrastructure project includes the installation of a 12m underground steel pipeline through the Newmarket area in Auckland. The pipes are welded together on site and NDT testing is required for the 300 expected welds.

Technics and technology used

Phased Array (PAUT) scanning is used to inspect butt welded pipe from inside of pipe. This technique is particularly well suited for comprehensive and time-efficient inspection.

The biggest challenge is to provide the service when needed, keeping up with the weld production (several per day) as the pipeline can only progress when the pipe welds have been successfully inspected and cleared.

To achieve this, inspections are carried inside the pipe, after travelling underground to the latest sections welded, and results of the scan are indicated on the spot for clearance or for remediation of defects.


So far up to 75 joints/welds have been inspected from late July to late September 2019. The technology choice has been vindicated and delivered as per expectations.

We will be working side-by-side with site managers through the different stages of this project till July 2020.