Non Destructive Pipeline Condition Assessment - Hutt Valley Outfall pipeline

A key feature of the Hutt Valley wastewater system is an 18.3 kilometre land based outfall pipeline. The condition of this pipeline, which was commissioned in 1962 is a major consideration in planning for renovation or replacement by Hutt City Council. 

Investigations of pipe condition inspection options led MWH to a patented electromagnetic technology (PureEM™) developed by Pure Technologies. The Australasian branch of Pure Technologies was engaged to undertake a survey using their proprietary equipmentin May 2013. 

Following the data analysis, physical validation testing was undertaken on selected pipes by excavating and confirming the amount of distress that was reported from the PureEM survey. The correlation was very high, confirming the accuracy of the use of this technology for this pipeline. 

In order to detect leaks, Pure Technologies were also commissioned to undertake a survey using their patented SmartBall® inspection technology in November 2013. This in-line tool is “free floating” and locates leaks and gas pockets in pressurised pipes by measurement of acoustic activity. 

This paper describes the investigations undertaken during these condition surveys, the challenges of planning and completing the inspections and the modern non destructive condition inspection plus assessment options which are now available.